Dissertations / Theses on the topic 'CONVERSION GAIN'

Emerging applications driven by low voltage level power sources, such as photovoltaics, batteries and fuel cells require static power converters for appropriate energy conversion and conditioning to supply the requirements of the load system. Increasingly, for applications such as grid connected inverters, uninterruptible power supplies (UPS), and electric vehicles (EV), the performance of a high efficiency high static gain power converter is of critical importance to the overall system. Theoretically, the conventional boost and buck-boost converters are the simplest non-isolated topologies for voltage step-up. However, these converters typically operate under extreme duty ratio, and severe output diode reverse recovery related losses to achieve high voltage gain. This thesis presents derivation, analysis and design issues of advanced high step-up topologies with coupled inductor and voltage gain extension cell. The proposed innovative solution can achieve significant performance improvement compared to the recently proposed state of the art topologies. Two unique topologies employing coupled inductor and voltage gain extension cell are proposed. Power converters utilising coupled inductors traditionally require a clamp circuit to limit the switch voltage excursion. Firstly, a simple low-cost, high step-up converters employing active and passive clamp scheme is proposed. Performance comparison of the clamps circuits shows that the active clamp solution can achieve higher efficiency over the passive solution. Secondly, the primary detriment of increasing the power level of a coupled inductor based converters is high current ripple due to coupled inductor operation. It is normal to interleaved DC-DC converters to share the input current, minimize the current ripple and increase the power density. This thesis presents an input parallel output series converter integrating coupled inductors and switched capacitor demonstrating high static gain. Steady state analysis of the converter is presented to determine the power flow equations. Dynamic analysis is performed to design a closed loop controller to regulate the output voltage of the interleaved converter. The design procedure of the high step-up converters is explained, simulation and experimental results of the laboratory prototypes are presented. The experimental results obtained via a 250 W single phase converter and that of a 500 W interleaved converter prototypes; validate both the theory and operational characteristics of each power converter.

COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
A conversão de comprimento de onda de sinais por meio de técnicas totalmente ópticas é um assunto inovador e de extrema necessidade para as redes com roteamento de comprimento de onda; a técnica de conversão de comprimentos de onda por modulação de ganho cruzado é uma das mais simples, em princípio, que atinge este objetivo. Duas modalidades são apresentadas neste trabalho: a clássica, também conhecida por pump & probe, e uma nova, a de modulação de ganho cruzado do espectro da ASE em um SOA. A técnica pump e probe é apresentada, assim como um experimento baseado nesta. A técnica de modulação de ganho cruzado da ASE é explorada como alternativa à técnicas de conversão de comprimento de onda que necessitam de outra fonte de luz, para a qual o sinal deve ser convertido. Na modulação de ganho cruzado da ASE, o sinal é convertido de luz coerente para incoerente; e, uma vez modulado o espectro da ASE do SOA, este é filtrado no comprimento de onda que se deseja obter a conversão. Assim, este conversor pode ser sintonizável, já que não é um parâmetro de entrada que define o comprimento de onda convertido, e sim um filtro passa-faixa ao fim do dispositivo. Para se avaliar os tempos de resposta da técnica, a conversão é feita utilizando-se pulsos elétricos ultracurtos (50 ps), o que não havia sido feito até então.
Wavelength conversion of optical signals by all-optical techniques is an innovative and necessary technology for wavelength routed networks in the near future; the cross-gain modulation method is one of the simplest, in form, to attain this goal. Two categories of the main technique are presented: the classic, also known as pump and probe, and a novel one, named cross- gain modulation of the ASE spectrum of a SOA. The cross-gain modulation of the ASE spectrum is explored here as an alternative to previous all-optical wavelength conversion techniques that require another light source, to which the incoming signal is to be converted; the signal is converted from coherent to incoherent light; and, once modulated throughout the SOA`s ASE spectrum, the signal is then filtered at the central wavelength it is desired to be converted. Thus, this particular wavelength converter can be tunable, in the sense that it is reconfigurable, since a band pass filter located at the end of the device selects what wavelength the signal will be converted to. In order to assess the response times of the technique, the conversion is made for ultra short electrical pulses (50 ps), a feature unknown until now.

L’amplificateur optique à semi-conducteurs (SOA) est désormais un composant multifonctiormel capable d’intégrer une liaison opto-hyperfréquence et de réaliser des fonctions tout-optiques. Dans cette étude, nous utilisons le SOA comme convertisseur de signaux hyperfréquences (HP) en exploitant la modulation croisée de son gain (XGM). Deux architectures ont été étudiées : tout d’abord le SOA a été utilisé comme mélangeur tout-optique et ensuite comme mélangeur électro-optique. Cette étude est réalisée à la fois expérimentalement sur un banc de mesures, théoriquement à partir d’équations petit-signal, et par simulation à l’aide d’un modèle développé sous le logiciel ADS-d’Agilent Technologies. Les résultats théoriques et les simulations ont été validés suite à leur confrontation aux résultats expérimentaux. Ils ont été ensuite utilisés tout au long de cette étude. Nous avons mesuré les performances statiques et dynamiques ainsi que la linéarité du mélangeur tout-optique. Le gain de conversion a été étudié en fonction des différents paramètres du mélange et nous avons montré qu’il est directement lié au gain optique du SOA et qu’il lui est toujours inférieur. L’émission spontanée amplifiée (ASE) générée par le SOA a été étudiée comme une source optique modulée participant au phénomène du mélange et le bruit de phase du signal converti a aussi été analysé. Les deux mélangeurs ont réalisé la conversion de signaux codés selon différents formats de modulation numérique complexes (QPSK, 16 et 64 QAM). Une conversion efficace avec un gain de conversion positif, sans distorsion ni dégradation significative sur les données numériques converties, a pu être réalisée, prouvant la capacité de nos mélangeurs à être insérés dans un système de communication complet
The Semiconductor Optical Amplifier (SOA) is a multifunctional device that can be integrated into a Radiofrequency-optical link and carry out all-optical functions. In this study, the SOA is used as a hyperfrequency (HP) converter based on Cross Gain Modulation (XGM). Two architectures have been studied: an SOA is firstly used as an all-optical microwave mixer and secondly as an electro-optical mixer. This study is realized both experimentally and theoretically both with small-signal modelling and a model developed under ADS software (Agilent Technologies). The theoretical results have been compared to the simulation results obtained with the aid of ADS and to the experimental results. All the obtained results are in good agreernent and the SOA model developed under ADS has been validated and uses throughout this study. We have measured the static and dynamic performances and the linearity of the all-optical mixer. The conversion gain has been studied with different parameters of the mixer and we have proved that it is directly related to the optical gain of SOA. The Amplified Spontaneous Emission (ASE) generated by the SOA acts as an optical modulated source participing in mixing phenomenon. The phase noise of the converted signal has been also analyzed. The two mixers allow the conversion of digital signals with complex modulation formats (QPSK, 16 and 64 QAM). An effective conversion with a positive conversion gain, without significant distortion or degradation of the converted numerical data, has been found, proving the ability of our mixers to be used as a part of a complete communication system

Mestrado em Engenharia Zootécnica - Produção Animal - Instituto Superior de Agronomia / Faculdade de Medicina Veterinária
The effect of different standardized ileal digestible tryptophan:lysine ratios, in diets with low crude protein on the zootechnical performances of pigs between 20 and 40 kg, was studied using 120 pigs in a five week trial. The 120 pigs were allotted to four experimental diets, 30 animals per diet and placed in cages in groups of 3 pigs per cage. Diet 1 was the control diet, with a level of 16,5% crude protein and standardized ileal digestible tryptophan:lysine ratio of 20,7%; diets 2, 3 and 4 were diets with a low crude protein level (14,5%) and the standardized ileal digestible tryptophan:lysine ratios were 17,4%, 20,5% and 23,5%, respectively. The average daily feed intake and the average daily gain decreased in pigs fed diet 2 compared to pigs fed diet 1 (P=0,0432; P=0,0187, respectively). The average daily feed intake, average daily gain and feed conversion ratio were not significantly different between diets 1 and 3 and between diets 3 and 4. These results suggest that it is possible to reduce the level of crude protein in two percentage points, as long as balance is maintained in the standardized ileal digestible tryptophan:lysine ratio at 20,5%

O experimento foi conduzido na FZEA/USP, com objetivo de comparar a utilização de fontes orgânicas de enxofre com a flor de enxofre na dieta de bovinos, com base no ganho de peso, conversão alimentar, concentração de enxofre e cobre no sangue, fígado e rim, e características da carcaça (experimento I), além de parâmetros ruminais (experimento II). No experimento I, 32 novilhos Nelore foram confinados e receberam ração total pelo sistema ?calan gate?, sendo divididos nos tratamentos: controle; flor de enxofre; metionina e carboquelatado. A cada 28 dias foram pesados, e foram colhidas amostras de sangue para posterior análise. Após 84 dias, foram abatidos e foram colhidas amostras de fígado e rim. No experimento II, oito novilhos foram canulados e divididos nos mesmos tratamentos já descritos. Durante cinco dias foi amostrado líquido ruminal para contagem de protozoários e análise de pH. Também foram incubados saquinhos de náilon para determinação da degradabilidade da matéria seca, proteína bruta e fibras em detergente neutro e ácido das dietas. Os tratamentos não influenciaram o ganho de peso e a conversão alimentar no período total de confinamento, porém, o carboquelatado proporcionou ganho de peso 11% maior que a flor de enxofre nos primeiros 28 dias de confinamento. Não foram encontradas diferenças entre as fontes para concentração de enxofre e cobre no sangue, porém, no fígado, as fontes orgânicas proporcionaram as menores concentrações de enxofre e a metionina, as menores concentrações de cobre. Não houve efeito das fontes estudadas na concentração de enxofre e cobre no rim, no rendimento de carcaça a na maciez da carne, bem como na degradabilidade e no pH ruminal. Entretanto, o carboquelatado aumentou a quantidade total de protozoários ciliados, sendo uma alternativa interessante para suplementação de bovinos no inicio do período de confinamento.
This research was carried out at FZEA/USP to compare the utilization of organic sulphur sources to elemental sulphur in bovines? diet, through analyses of weight gain, feed conversion, liver and kidney sulphur and copper concentrations and carcass characteristics (experiment I), and ruminal parameters (experiment II). During experiment I, 32 Nellore steers were confined and were fed a total ration through ?calan gate? system. They were divided into the treatments: control; elemental sulphur; methionine and carboquelated. Each 28 days, they were weighted and blood samples were taken to posterior analysis. After 84 days, they were slaughtered and samples of liver and kidney were taken. During experiment II, eight steers were cannuladed and divided into the same described treatments. During five days, ruminal liquid was sampled to protozoa count and pH determination. Also, nylon bags were incubated to determinate the degradability of dietary dry matter, crude protein and acid and neutral detergent fiber. Treatments did not affect weight gain and feed conversion during whole feedlot period, however, carboquelated provided weight gain 11% higher than the elemental sulphur during the first 28 days of feedlot. There were no differences of sulphursources on sulphur and copper blood concentrations, however, in the liver, the organic sources provided lower sulphur concentrations and methionine provided lower copper concentration. The studied sources did not affect kidney sulphur and copper concentration, carcass yield, shear force, ruminal degradability and pH. However, carboquelated increased total amount of ciliate protozoa, and it is an interesting alternative to supplement bovines during the beginning of a feedlot period.

Ce travail de thèse concerne les circuits ultra-rapides pour la conversion analogique numérique performante en technologie bipolaire à hétérojonctions sur substrat Indium Phosphore (TBDH/InP). L'étude s'intéresse à la fonction principale qui est l'échantillonnage blocage. Elle a été menée par simulation de l'ensemble des blocs composant cette fonction. En particulier une étude extensive des cœurs des circuits Echantillonneurs/Bloqueurs a été effectuée pour différents paramètres électriques pour aboutir à des valeurs optimales réalisant un compromis entre la bande passante la résolution et la linéarité.Des architectures de circuits Echantillonneurs/Bloqueurs (E/B) avec ou sans l'étage d'amplification à gain variable ont été conçues, optimisées, réalisées et caractérisées et des performances à l'état de l'art ont été obtenues : des circuits E/B de bande passante supérieure à 50 GHz et cadencées à 70 Gs/s ont été réalisés pour les applications de communications optiques et des circuits de bande passante supérieure à 16 GHz cadencés à (2-8) Gs/s ont été réalisés pour la transposition de fréquence
This thesis concerns the design of high speed circuits in Indium phosphide heterojunction Bipolar technology for High performance analog to digital conversion (ADC).The study focuses on the Track and Hold block (THA) which is the main function of the ADC. The study was conducted by simulating all blocks of the THA circuit. In particular, an extensive study of the THA main block was performed for various electrical parameters to achieve optimal conditions in order to obtain a good tradeoff between resolution bandwidth and linearity. THA architectures circuits with or without Voltage Gain Amplifier stage were designed, optimized and characterized. High THA performances were achieved: THA circuit with a bandwidth greater than 50 GHz at 70 Gs/s were achieved for optical communications and circuits of bandwidth more than16 GHz at (2-8 GS /s) have been realized for down conversion operation

Dissertação de mestrado em Engenharia Zootécnica/Produção Animal
O objectivo deste trabalho foi comparar as performances zootécnicas de leitões submetidos a duas idades de desmame diferentes (21 vs 28 dias), as performances reprodutivas das porcas que originaram esses leitões e, posteriormente, analisar qual destas opções é a mais rentável, nas condições da exploração onde foi realizado o ensaio. Foram constituídos dois grupos: um com 5 porcas e os respectivos leitões (60) que foram desmamados aos 21 dias (D21) e outro com 6 porcas e os respectivos leitões (67) que foram desmamados aos 28 dias (D28). A partir do desmame, os leitões foram divididos em 4 grupos por critérios de idade ao desmame e sexo e alojados em 4 parques. Os leitões foram pesados ao nascimento e aos 7, 14, 21 e, no caso dos desmamados mais tarde, aos 28 dias. A partir do desmame, os porcos foram pesados uma vez por mês até aos 6 meses de vida, idade de abate. O alimento distribuído aos animais durante todo o período de ensaio foi pesado e, em cada mês, durante 5 dias consecutivos, foi também pesado o refugo a fim de avaliar a ingestão de alimento por parque. Verificou-se que não houve diferenças entre tratamentos em relação aos produtos dos partos, nos quais tiveram origem os leitões utilizados neste ensaio, bem como nos produtos da parição seguinte. Observou-se também que todas as porcas de ambos os tratamentos ficaram gestantes, apresentando um intervalo desmame-cobrição fecundante de 4 dias. Verificou-se que o PV dos leitões do tratamento D21 até ao desmame foi superior (P<0,05) a partir do 17º dia de idade. Desde o desmame até ao abate os PV dos porcos do tratamento D21 foram sempre superiores (P<0,05). Ao nível da ingestão de alimento, observou-se que os valores para os dois tratamentos não diferiram, apesar de os animais desmamados mais cedo terem apresentado uma tendência para uma maior ingestão. Verificou-se também que, aparentemente, o IC foi melhor nos animais do tratamento D28. Economicamente, verificou-se um acréscimo de +0,96€/porco a favor do desmame aos 21 dias. Conclui-se, então, que, não tendo havido diferenças significativas entre os dois desmames no crescimento dos leitões/porcos e na eficiência reprodutiva das porcas, o desmame aos 21 dias poderá ser mais vantajoso dado que permitirá que as porcas produzam mais leitões na sua vida útil.
ABSTRACT - The aim of this study was to compare the zootechnical performances of piglets subjected to two different weaning ages (21 vs 28 days), the reproductive performance of their sows and analyze which of these options is the most profitable in the conditions of the farm where the trial was performed. Sows and their piglets were randomly assigned to two groups: one with 5 sows and their piglets (60), weaned at 21 days (D21) and the other with 6 sows and their piglets (67), weaned at 28 days (D28). After weaning, the piglets were divided in 4 groups by criteria of weaning age and sex and housed in 4 pens. Piglets were weighed at birth and at 7, 14, 21 and, in the case of those weaned later, at 28 days. After weaning, pigs were weighed once a month until 6 months of age, when they were slaughtered. All food distributed to animals during the trial was weighed and, in each month for 5 consecutive days, leftovers was also weighed to assess the intake per pen. There weren´t any differences between the two groups in what refers to the prolificacy of sows in the farrowing where those piglets were born that as well as in the following farrowing. It was also observed that all sows of both treatments became pregnant after weaning, showing a weaning-mating interval of 4 days. It has been found that the D21 piglets weight was higher (P <0.05) from day 17 of age to weaning. From weaning to slaughter, the D21 pigs weight were also always higher (P <0.05). In terms of food intake, we observed that the values for the two treatments didn´t differ, although the animals early weaned presented a trend ford a higher intake. It was also found an apparent better feed conversion in D28 animals. Economically, there was an increase of +0.96€/pig in favor of 21 days weaning. Given the absence of substantial differences between the two weaning ages in the growth of piglets/pigs and in the reproductive efficiency of sows, it was concluded that weaning at 21 days may be more beneficial since it will allow sows to produce more piglets in their productive life.

Conselho Nacional de Desenvolvimento Científico e Tecnológico
Aimed to evaluate the performance and ingestive behavior of cattle finished in feedlot with whole grains based on corn, white oat or rice with hulls. Forty- five animals from double-cross cross breeding involving Charolais and Nellore races belonging to the Beef Cattle Department, with initial average weight and age of 310 kg and 20 months for the steers and 350 kg and 32 months for the heifers were used. The animals were randomly distributed in the treatments, blocked according the category (8 steers and 7 heifers), totaling 15 animals per treatment placed in individual stalls. The diets were calculated in order to be isonitrogenous, being the treatments composed by: Rice (85% of rice + 15% core protein); Oat (85% oat + 15% core protein) and Corn (85% corn + core protein), besides limestone and urea in order to balance the demands of calcium and nitrogen, respectively. The daily dry matter and crude protein intake did not differ among the different tested grains. The intake of ether extract, neutral detergent fiber and hemicellulose were superior for the animals that consumed oat grain, presenting values of 0.09; 0.65 and 0.34 % LW, respectively. Regarding the cellulose intake, the treatments oat (0.22% LW) and rice (0.18% LW) were superior to the corn treatment (0.06% LW). Regarding the intake of total digestible nutrients, non- fiber carbohydrates and total carbohydrates, there were no significant difference. For the variable final weight the animals of corn and oat treatment were superior to the rice treatment. Regarding the daily average gain, the animals fed with corn were superior to the oat treatment, being this one superior to the animals fed with rice, presenting values of 1.30; 1.07 and 0.71 kg, respectively. The animals of rice treatment obtained worse feed conversion compared to the corn and oat treatment that were better and similar, being 11.15; 6.07 and 7.99 kg LW/ kg DM, respectively. The animals that received the diet based on corn remained more time in idle (19.87 hours) compared to the animals fed with rice (18.58 hours), and these ones remained more time in idle in relation to the ones fed with oat (15.64 hours). Regarding the rumination time, the animals that consumed the diet based on oat, spent more time ruminating (6.38 hours) than the animals of rice treatment (3.23 hours) and these ones spent more time ruminating than the animals of the corn based diet (1.90 hours). The animals fed with corn remained less time eating and presented higher number of daily meals when compared to the other treatments. The use of diets with whole grain on feedlot cattle finishing is a viable alternative, wherein corn or oat presented better animal response in relation to rice with hulls. In this type of diet, the NDF level influence the time spent by the animals with rumination and idle, however, for the feeding time, there is no variation.
Objetivou-se avaliar o desempenho e comportamento ingestivo de bovinos terminados em confinamento com grãos inteiros a base de milho, aveia branca ou arroz com casca. Foram utilizados 45 animais oriundos do cruzamento bicross envolvendo as raças charolês e nelore pertencentes ao Laboratório de Bovinocultura de Corte, com peso e idade média inicial de 310 kg e 20 meses para os novilhos e 350 kg e 30 meses para as novilhas. Os animais foram distribuídos ao acaso nos tratamentos, bloqueados conforme a categoria (8 novilhos e 7 novilhas), totalizando 15 animais por tratamento e alocados em baias individuais. As dietas foram calculadas para serem isonitrogenadas, sendo os tratamentos compostos por: Arroz (85% de arroz + 15% de núcleo proteico); Aveia branca (85% aveia + 15% núcleo proteico) e Milho (85% milho + 15% núcleo proteico), além de calcário calcítico e ureia para equilibrar as exigências de cálcio e nitrogênio, respectivamente. Os consumos diários de matéria seca e proteína bruta não diferiram entre os diferentes grãos testados. Para os consumos de extrato etéreo, fibra em detergente neutro e hemicelulose foram superiores para os animais que consumiram grão de aveia, apresentando valores de 0,09; 0,65 e 0,34 % PV, respectivamente. Já para o consumo de celulose, os tratamentos aveia (0,22 % PV) e arroz (0,18 % PV) foram superiores ao tratamento milho (0,06 % PV). Em relação aos consumos de nutrientes digestíveis totais, carboidratos não fibrosos e carboidratos totais, não obtiveram diferenças significativas. Para a variável peso final os animais dos tratamentos milho e aveia foram superiores ao tratamento arroz. Já para o ganho médio diário, os animais alimentados com milho foram superiores ao tratamento aveia que foi superior aos animais alimentados com arroz, apresentando valores de 1,30; 1,07 e 0,71 kg, respectivamente. Os animais do tratamento arroz obtiveram pior conversão alimentar em comparação aos tratamentos milho e aveia que foram melhores e semelhantes, sendo 11,15; 6,07 e 7,99 kg PV/kg MS, respectivamente. Os animais que receberam dieta à base de milho permaneceram maior tempo em ócio (19,87 horas) comparado aos animais alimentados com arroz (18,58 horas), que por sua vez permaneceram mais tempo em ócio em relação aos alimentados com aveia (15,64 horas). Em relação ao tempo de ruminação, observa-se que os animais que consumiram dieta à base de aveia ruminaram mais tempo (6,38 horas) que os animais do tratamento com arroz (3,23 horas) e estes por sua vez, mais tempo que os animais da dieta à base de milho (1,90 horas). Para os animais alimentados com milho, estes permaneceram menos tempo se alimentado e apresentaram maior número de refeições diárias, quando comparado aos demais tratamentos. O uso de dietas com grãos inteiros na terminação de bovinos confinados é uma alternativa viável, sendo que o milho ou aveia apresentam melhor resposta animal em relação ao arroz em casca. Nesse tipo de dieta, o nível de FDN exerce influência sobre os tempos despendidos pelos animais em ruminação e ócio, no entanto, para o tempo de alimentação estes não sofreram alterações.

Mestrado em Engenharia Zootécnica - Produção Animal - Instituto Superior de Agronomia / Faculdade de Medicina Veterinária
The effect of different digestive ileal standart of valine:lysine ratios on low crude protein content, on the zootecnic performances of 12 to 30 kg piglets was studied using 180 piglets, on a 4 week trial. Those 180 piglets were distributed on 5 different experimental diets, with 36 animals each and installed on a 3 piglets per cage. The diets were elaborated with a 15, 5% crude protein content with a digestive ileal standart of valine:lysine ratio of 60, 65, 70, 75 and 80%, diets 1, 2, 3, 4 and 5 respectively. The average daily gain was higher on the piglets with a 70% ratio (diet 3), comparatively with diets 2, 4 and 5 (P=0, 0597). The final weight, average daily intake and feed convertion ratio were not significantly different a mong diets. These results show that the best digestive ileal standart ratio of valine:lysine is the 70% for piglests with live weight of 12 to 30 kg

Ces dernières années, un intérêt croissant pour les systèmes électroniques de puissance a été motivé par l'émergence de sources d'énergie distribuées et renouvelables raccordées aux réseaux électriques. Dans ce contexte, la nécessité de topologies de faibles puissances alimentées par quelques modules photovoltaïques, en évitant l'utilisation de transformateurs, a ouvert l'étude de convertisseurs spéciaux et l’étude des stratégies de commande associées afin d’assurer la stabilité, la fiabilité et un rendement élevé du dispositif. Une possible solution est d’utiliser un dispositif générique connu dans la littérature scientifique et commerciale comme « micro-onduleur » ou «convertisseur intégré au module » qui avec le module photovoltaïque définit un produit « plug and play » appelé "module AC".Ce travail est consacré à l'étude d'un micro-onduleur monophasé avec deux étapes sans transformateur raccordée au réseau. La topologie proposée est composé d’un convertisseur DC-DC non isolé élévateur avec un gain quadratique et un onduleur réducteur lié au réseau connectés en cascade. Le convertisseur DC-DC extrait en permanence la puissance maximale du module photovoltaïque malgré les changements dans les conditions environnementales. L'étape DC-AC injecte la puissance extraite par l'étape DC-DC dans le réseau et assure un niveau élevé de qualité de l’énergie. Les efforts de recherche de ce travail sont concentrés sur la mise au point de commandes utilisant comment base, la théorie de contrôle par mode de glissement, qui conduit à une mise en œuvre simple avec une description théorique complète validée á partir de simulations et expérimentations.Après avoir décrit l'état de l’art dans le premier chapitre, le manuscrit est divisé en quatre chapitres, qui sont dédiés respectivement à l’algorithme de recherche du point de puissance maximale (MPPT), á l’étape de conversion DC-DC, á l'étape de conversion DC-AC et finalement au micro-onduleur complet. Un nouvel algorithme de recherche extrémal du point de puissance maximale est développé (SM-ESC). Pour la étape DC-DC, le convertisseur élévateur quadratique avec seulement un interrupteur contrôlé est étudié utilisant le concept de résistance sans perte par mode de glissement (de l’acronyme anglais : Sliding-Mode Loss-Free-Resistor – SM-LFR) afin d’obtenir un gain de tension élevé avec un fonctionnement sûr et compatible avec l’algorithme MPPT. Pour la étape DC-AC, le convertisseur de pont complet est contrôlé comme un onduleur de source de puissance (de l’acronyme anglais : Power Source Inverter - PSI) en utilisant une commande par mode de glissement qui poursuit une référence sinusoïdale de courant de sortie. Cette commande est complétée par une boucle de régulation de la tension du bus DC qui assure une haute qualité d’énergie injectée dans le réseau. Enfin, les trois étapes constitutives sont fusionnées pour obtenir un micro-onduleur complètement contrôlé par la technique de mode de glissement, ce qui constitue le principal résultat et contribution de cette thèse
These last years, a growing interest in power electronic systems has been motivated by the emergence of distributed renewable energy resources and their interconnection with the grid. In this context, the need of low power topologies fed by a few photovoltaic modules avoiding the use of transformers opens the study of special converters and the associated control strategies ensuring stability, reliability and high efficiency. A resulted generic device known in the commercial and scientific literature as “microinverter” or “module integrated converter” performs a plug and play product together with the PV module called an “AC module”.This work is devoted to the study of a transformer-less single-phase double-stage grid-connected microinverter. The proposed topology has a non-isolated high-gain boost type DC-DC converter and a non-isolated buck type DC-AC converter connected in cascade through a DC bus. The DC-DC converter permanently extracts the maximum power of the PV module ensuring at the same time a good performance coping with power changes introduced by the change in the environmental conditions. The DC-AC stage injects the power extracted by the DC-DC stage into the grid ensuring a high level of power quality. The research efforts focus on the involved control functions based on the sliding mode control theory, which leads to a simple implementation with a comprehensive theoretical description validated through simulation and experimental results.After giving the state-of-the-art in the first chapter, the manuscript is divided into four chapters, which are dedicated to the Maximum Power Point Tracking (MPPT), the DC-DC stage and its control, the DC-AC stage and its control and the complete microinverter. A new Extremum Seeking Control (ESC) MPPT algorithm is proposed. The single-switch quadratic boost converter is studied operating as a Loss-Free-Resistor (LFR) obtaining a high DC output voltage level with a safe operation. The full-bridge converter is controlled as a Power Source Inverter (PSI) using a simple sliding-mode based tracking law, regulating the voltage of the DC bus and then ensuring a high power quality level in the grid connection. Finally, the three building blocks are merged to obtain a sliding mode controlled microinverter constituting the main result and contribution of the work

Thesis (M.S.)--School of Computing and Engineering. University of Missouri--Kansas City, 2005.
"A thesis in computer science." Typescript. Advisor: Deep Medhi. Vita. Title from "catalog record" of the print edition Description based on contents viewed June 23, 2006. Includes bibliographical references (leaves 68-71). Online version of the print edition.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Universidade Estadual Paulista (UNESP)
Foram utilizados 43 animais de três grupos raciais (GR), sendo 13 Alpino (8 machos e 5 fêmeas), 9 u Boer + u Alpino (4 machos e 5 fêmeas) e 21 Boer + o Alpino (11 machos e 10 fêmeas), dos quais 21 receberam rbST (4 machos e 3 fêmeas do grupo Alpino (A); 2 machos e 2 fêmeas do u BA e 6 machos e 4 fêmeas do BA) e 22 placebo (4 machos e 2 fêmeas A; 2 machos e 3 fêmeas u BA e 5 machos e 6 fêmeas BA). O hormônio de crescimento utilizado foi a somatotropina recombinante bovina (rbST) e os animais do tratamento 1 receberam o hormônio na quantidade de 0,3 mg/kg de peso vivo, a partir dos 45 dias, ajustada em intervalos de 14 dias. Os animais do tratamento 2 (controle) receberam solução salina na mesma dosagem e intervalo. Não foi observada nenhuma influência da somatotropina bovina recombinante nas características de desempenho avaliadas. Os machos foram superiores às fêmeas no ganho em peso do início da aplicação do hormônio aos 120 dias de idade, assim como no ganho médio diário de peso dos 60 aos 90, 90 aos 120 e do início da aplicação aos 120 dias de idade. O peso aos 90 e 120 dias de idade das fêmeas foram inferiores em relação aos machos. As fêmeas BA apresentaram maiores ganho em peso e ganho médio diário de peso dos 150 aos 180 dias em relação às demais. Não foi observada influência do hormônio de crescimento e do grupo racial para o peso ao cio, idade ao cio e idade para atingir 30 kg de peso vivo.
It was used 43 animals of three breed groups, wich 13 Alpine (8 males and 5 females), 9 u Boer + u Alpine (4 males and 5 females) e 21 Boer + o Alpine (11 males and 10 females), wich 21 received rbST (4 males and 3 females of Alpine group (A); 2 males and 2 females of u BA and 6 males and 4 females of BA) and 22 control (4 males and 2 females of A; 2 males and 3 females of u BA and 5 males and 6 females of BA).The growth hormone used was the bovine recombinant somatotropin (rbST) and the animals of treatment 1 received the hormone in the adjusted amount from 0,3 mg/kg of live weight in intervals of 14 days. The animals of treatment 2 (control) had received saline solution in the same dosage and interval. There was no influence of the recombinant bovine somatotropin in the evaluated characteristics of performance. The males had been bigger to the females in the weight gain of the application of the hormone to the 120 days of age, as well as in the daily average weight gain of the 60 to the 90, 90 to the 120 and of the application to the 120 days of age. The weight to the 90 and 120 days of age of the females had been smaler in relation to the males. The females BA had presented bigger weight gain and daily average weight gain of the 150 to the 180 days in relation to others. It was not observed influence of growth hormone and the breed group for weight to oestrus, age to oestrus and age to reach 30 kg live weight.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The creation of beef cattle in Brazil is growing every year we move forward due to improved production rates. One of the maids to the increase of these indices is the feedlot technologies. For animal feed are used with alternative energy foods market availability, as the shell of soybean and oat grain. This study was conducted to evaluate the shell of soybean and oat grain as a sole source or associated in concentrate on performance and feeding behavior of feedlot finished steers fraction. 36 steers with initial age of 20 months and average weight of 226 kg. The treatments were: soybean hull (concentrated fraction formed basically by shell soybean), oat grain (concentrate fraction formed primarily by grain oat) and mixture (concentrated fraction formed by pieces of husk from the grain equal soy beans and oat). The diet was composed of 50 % sorghum silage and 50 % concentrate on dry matter. The experimental design was completely randomized with the animal performance data were subjected to analysis of variance and F test using PROC GLM and means were compared by Student's ``t´´ test, α = 0.05 probability. Have animal data feeding behavior were compared using the PROC MIXED procedure with repeated measures on time and the means were compared by least significant difference test. Animals fed soybean hull consumed 1.597 % of body weight in neutral detergent fiber. Have animal treatment oat grain consumed in ether extract 0.085 % of live weight. The daily live weight gain of the animals did not differ (mean 0.984 kg/day), and the bark treatment of soybean obtained this result by best rumination efficiency of neutral detergent fiber (655.61 g/h), different treatment of oat grain that obtained by the total lipids. The dry matter intake was not altered by neutral detergent fiber content in this work. Both the bark of soybean as the oat grain provides similar performance in finishing beef cattle feedlot. Animals of the mixture showed higher feeding time (264 minutes), increased number of daily meals, less time ruminating (447.12 minutes), less time spent chewing (477.67 minutes), number of chewed by day and cake (59.59 and 28.667). Resulting in improved efficiency of rumination as dry matter, neutral detergent fiber.
A criação de bovinos de corte no Brasil vem crescendo a cada ano que avançamos, devido a melhora de índices produtivos. Uma das tecnologias empregadas para o incremento destes índices é o confinamento. Para a alimentação dos animais utilizam-se alimentos energéticos alternativos com disponibilidade de mercado, como a casca do grão de soja e a aveia branca. Este estudo foi conduzido com o objetivo de avaliar a casca do grão de soja e a aveia branca como única fonte ou associadas na fração concentrado sobre o desempenho e comportamento ingestivo de novilhos terminados em confinamento. Foram utilizados 36 novilhos com idade inicial de 20 meses e peso médio inicial de 226 kg. Os tratamentos foram: casca do grão de soja (fração concentrada formada basicamente por casca do grão de soja), grão de aveia branca (fração concentrada formada basicamente por grãos de aveia branca) e mistura (fração concentrada formada por partes iguais de casca do grão de soja e grãos de aveia branca). A dieta foi composta de 50% de silagem de sorgo e 50% de concentrado com base na matéria seca. O delineamento experimental utilizado foi o inteiramente casualizado sendo os dados referentes ao desempenho animal foram submetidos à análise de variância e teste F, pelo PROC GLM e as médias comparadas através do teste ``t´´ de Student, a α=0,05 de probabilidade. Já os dados do comportamento ingestivo animal foram comparados pelo procedimento PROC MIXED com avaliações repetidas no tempo e as médias, comparadas pelo teste de diferença mínima significativa. Animais alimentados com casca do grão de soja consumiram 1,597% do peso vivo em fibra em detergente neutro. Já animais do tratamento grão de aveia branca consumiram em extrato etéreo 0,085% do peso vivo. O ganho peso vivo diário dos animais não diferiu (média de 0,984 kg/dia), sendo que o tratamento casca do grão de soja obteve este resultado pela melhor eficiência de ruminação da fibra em detergente neutro (655,61 g/h), diferente do tratamento grão de aveia branca que obteve pela fração lipídica da dieta. O consumo de matéria seca não foi alterado pelo teor de fibra em detergente neutro neste trabalho. Tanto a casca do grão de soja como o grão de aveia branca proporcionam desempenho similar na terminação de novilhos em confinamento. Animais do tratamento mistura apresentaram maior tempo de alimentação (264 minutos), maior número de refeições diárias, menor tempo de ruminação (447,12 minutos), menor tempo despendido para mastigação (477,67 minutos), número de mastigadas por bolo e dia (59,59 e 28.667). Resultando em melhor eficiência de ruminação de matéria seca como de fibra em detergente neutro.

This thesis describes an investigation into the suitability of complementary metal oxide semiconductor (CMOS) active pixel sensor (APS) devices for scientific imaging applications. CMOS APS offer a number of advantages over the established charge-coupled device (CCD) technology, primarily in the areas of low power consumption, high-speed parallel readout and random (X-Y) addressing, increased system integration and improved radiation hardness. The investigation used a range of newly designed Test Structures in conjunction with a range of custom developed test equipment to characterise device performance. Initial experimental work highlighted the significant non-linearity in the charge conversion gain (responsivity) and found the read noise to be limited by the kTC component due to resetting of the pixel capacitance. The major experimental study investigated the contribution to dark signal due to hot-carrier injection effects from the in-pixel transistors during read-out and highlighted the importance of the contribution at low signal levels. The quantum efficiency (QE) and cross-talk were also investigated and found to be limited by the pixel fill factor and shallow depletion depth of the photodiode. The work has highlighted the need to design devices to explore the effects of individual components rather than stand-alone imaging devices and indicated further developments are required for APS technology to compete with the CCD for high-end scientific imaging applications. The main areas requiring development are in achieving backside illuminated, deep depletion devices with low dark signal and low noise sampling techniques.

Emerging technologies such as Bluetooth and 802.11b (Wi-Fi) have fuelled the growth of the short-range communication industry. Bluetooth, the leading WPAN (wireless personal area network) technology, was designed primarily for cable replacement applications. The first generation Bluetooth products are focused on providing low-cost radio connections among personal electronic devices. In the WLAN (wireless local area network) arena, Wi-Fi appears to be the superior product. Wi-Fi is designed for high speed internet access, with higher radio power and longer distances. Both technologies use the same 2.4GHz ISM band. The differences between Bluetooth and Wi-Fi standard features lead to a natural partitioning of applications. Nowadays, many electronics devices such as laptops and PDAs, support both Bluetooth and Wi-Fi standards to cover a wider range of applications. The cost of supporting both standards, however, is a major concern. Therefore, a dual-mode transceiver is essential to keep the size and cost of such system transceivers at a minimum. A fully integrated low-IF Bluetooth receiver is designed and implemented in a low cost, main stream 0.35um CMOS technology. The system includes the RF front end, frequency synthesizer and baseband blocks. It has -82dBm sensitivity and draws 65mA current. This project involved 6 Ph.D. students and I was in charge of the design of the channel selection complex filter is designed. In the Bluetooth transmitter, a frequency modulator with fine frequency steps is needed to generate the GFSK signal that has +/-160kHz frequency deviation. A low power ROM-less direct digital frequency synthesizer (DDFS) is designed to implement the frequency modulation. The DDFS can be used for any frequency or phase modulation communication systems that require fast frequency switching with fine frequency steps. Another contribution is the implementation of a dual-mode 802.11b/Bluetooth receiver in IBM 0.25um BiCMOS process. Direct-conversion architecture was used for both standards to achieve maximum level of integration and block sharing. I was honored to lead the efforts of 7 Ph.D. students in this project. I was responsible for system level design as well as the design of the variable gain amplifier. The receiver chip consumes 45.6/41.3mA and the sensitivity is -86/-91dBm.

Orientador: Heraldo César Gonçalves
Banca: André Mendes Jorge
Banca: Francisco de Assis Fonseca de Macedo
Resumo: Foram utilizados 43 animais de três grupos raciais (GR), sendo 13 Alpino (8 machos e 5 fêmeas), 9 u Boer + u Alpino (4 machos e 5 fêmeas) e 21 Boer + o Alpino (11 machos e 10 fêmeas), dos quais 21 receberam rbST (4 machos e 3 fêmeas do grupo Alpino (A); 2 machos e 2 fêmeas do u BA e 6 machos e 4 fêmeas do BA) e 22 placebo (4 machos e 2 fêmeas A; 2 machos e 3 fêmeas u BA e 5 machos e 6 fêmeas BA). O hormônio de crescimento utilizado foi a somatotropina recombinante bovina (rbST) e os animais do tratamento 1 receberam o hormônio na quantidade de 0,3 mg/kg de peso vivo, a partir dos 45 dias, ajustada em intervalos de 14 dias. Os animais do tratamento 2 (controle) receberam solução salina na mesma dosagem e intervalo. Não foi observada nenhuma influência da somatotropina bovina recombinante nas características de desempenho avaliadas. Os machos foram superiores às fêmeas no ganho em peso do início da aplicação do hormônio aos 120 dias de idade, assim como no ganho médio diário de peso dos 60 aos 90, 90 aos 120 e do início da aplicação aos 120 dias de idade. O peso aos 90 e 120 dias de idade das fêmeas foram inferiores em relação aos machos. As fêmeas BA apresentaram maiores ganho em peso e ganho médio diário de peso dos 150 aos 180 dias em relação às demais. Não foi observada influência do hormônio de crescimento e do grupo racial para o peso ao cio, idade ao cio e idade para atingir 30 kg de peso vivo.
Abstract: It was used 43 animals of three breed groups, wich 13 Alpine (8 males and 5 females), 9 u Boer + u Alpine (4 males and 5 females) e 21 Boer + o Alpine (11 males and 10 females), wich 21 received rbST (4 males and 3 females of Alpine group (A); 2 males and 2 females of u BA and 6 males and 4 females of BA) and 22 control (4 males and 2 females of A; 2 males and 3 females of u BA and 5 males and 6 females of BA).The growth hormone used was the bovine recombinant somatotropin (rbST) and the animals of treatment 1 received the hormone in the adjusted amount from 0,3 mg/kg of live weight in intervals of 14 days. The animals of treatment 2 (control) had received saline solution in the same dosage and interval. There was no influence of the recombinant bovine somatotropin in the evaluated characteristics of performance. The males had been bigger to the females in the weight gain of the application of the hormone to the 120 days of age, as well as in the daily average weight gain of the 60 to the 90, 90 to the 120 and of the application to the 120 days of age. The weight to the 90 and 120 days of age of the females had been smaler in relation to the males. The females BA had presented bigger weight gain and daily average weight gain of the 150 to the 180 days in relation to others. It was not observed influence of growth hormone and the breed group for weight to oestrus, age to oestrus and age to reach 30 kg live weight.
Mestre

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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
We studied the effect of substitution of 0, 33, 66 and 100% of ground corn (GC) by soybean hulls (SH) in diet’s concentrate portion of 144 Nellore heifers of 24 to 30 months of age and 263.40 + 13.90 kg of body weight in beginning of feedlot and slaughtered at different weights (<340, 340-370, 370-400 and >400 kg). There was no significant interaction between levels of substitution of GC by SH and slaughter weight classes being these effects studied separately. Diets were composed of 90 % concentrate and 10 % corn silage. The experimental period was 112 days, including the period of adaptation. The dry matter intake was not altered by substitution of GC by SH with mean values of 2.51 % of body weight. The substitution level of GC by SH resulted in a linear increase in NDF intake (1.08, 2.03, 2.92 and 3.78 kg/day) and reduced consumption of NDT (5.78, 5 16, 5.03 and 5.12 kg/day) with the addition of 0, 33, 66 and 100 % of GC by SH substitution, respectively. The average daily weight gain decreased linearly (1.24, 1.11, 1.02 and 0.89 kg / day), while feed conversion increased (6.20, 7.08, 7.77 and 8.67 kg DM intake/kg ADG) for the levels of 0, 33, 66 and 100% SH in the diet, respectively. The body condition score was not influenced by levels of substitution of GC by SH presenting mean values of 3.51 points. The body measurements were not affected by treatments, both on the back as the withers, with mean values of 138.5 and 133.25 cm, respectively. Measures of thorax perimeter and body length decreased linearly with the inclusion of SH levels. The slaughter weight decreased linearly with values of 383.52, 374.71, 363.25 and 366.27 kg for levels of 0, 33, 66 and 100 % replacement of GC for SH, respectively, however the hot carcass weight or cold were not affected by the replacement of GC by SH and showed average values of 203.52 and 199.25 kg, respectively. There was no effect of dietary treatment on hot carcass yield showing mean values of 54.92 %. The conformation of the carcasses was not affected by the replacement of GC by SH, with average values of 9.16 points. The subcutaneous fat thickness and loin eye area were not affected by dietary treatments and showed mean values of 5.3 mm and 53.08 cm2, respectively. The yields of primary carcass cut (front, special needle and side cut) were not affected by SH inclusion levels and showed average values of 36.52, 51.72 and 11.55%, respectively. The objective measurements of carcass were not affected by replacement levels of GC by SH. It was found linear effect of treatments on the compactness of carcasses showing average values of 1.56, 1.57, 1.51 and 1.45 cm/kg of cold carcass, to replacing levels of 0, 33, 66 and 100% of SH, respectively. The color and texture of meat were not influenced by dietary treatments and showed average values of 3.30 and 3.19 points, respectively. The marbling of the meat was not influenced by the substitution of GC by SH presenting mean values 8.56 points, with amplitude values between 2 and 17 points. The elevation of slaughter weight resulted in increased weights of hot and cold carcass. Animals slaughtered with weight >400kg had hot carcass yield of 52.76 %, lower than the group of 370-400 kg (56.55 %). The subcutaneous fat thickness was not affected by slaughter weight in any of the expression forms of this variable, with mean values of 5.26 mm and 2.67% of the cold carcass weight. The loin eye area increased with the increase of slaughter weight, and the correlation between these variables was 0.62 (P=0.001), however, when this variable was expressed to 100 kg cold carcass this difference disappeared, with average scores of 26,72 cm2 for each 100 kg of cold carcass. The animals slaughtered with weight >400kg showed better conformation (9.79 points) compared to the other weight classes did not differ among themselves. There was a significant effect of slaughter weight on the carcasses length, arm perimeter and cushion thickness which increased 5.9, 2.3 and 3.12 cm, respectively, amounted to slaughter weight of <340 to >400 kg. Animals slaughtered with weight >400kg had higher carcass compactness compared to the other treatments (1.65 cm long/ kg of cold carcass weight). The absolute weights of primary cuts of the carcass increased with the slaughter weight, however to adjust the weights of the front and rear to 100 kg of cold carcass, this difference disappeared, with values of 36.59 and 51.99%, respectively. The color and texture of the meat were not influenced by slaughter weights showing average values of 3.28 and 3.19 points, respectively. The marbling of the meat was lower in the group of animals slaughtered weighing less than 340 kg compared to the other weight classes did not differ among themselves. It was concluded which although not influence the main carcass characteristics, the replace of ground corn by soybean hulls in high concentrate diets is not efficient because has depressing effect on the productive performance, notably weight gain and feed conversion. Feedlot Nellore heifers must not be slaughtered weighing less than 340 kg because they have lower carcass weight and less marbling of the meat.
Foram estudados os efeitos da substituição de 0, 33, 66 e 100% do milho moído (MM) por casca do grão de soja (CS), na porção concentrada da dieta, de 144 novilhas de descarte da raça Nelore com 24 a 30 meses de idade e 263,40 + 13,90 kg de peso vivo médio inicial, terminadas em confinamento e abatidas com diferentes pesos (<340; 340-370; 370-400 e >400 kg). Não foi constatada interação significativa entre os níveis de substituição do MM pela CS e classes de peso ao abate sendo estes efeitos estudados separadamente. As dietas foram constituídas de 90% de concentrado e 10% de silagem de milho. O período experimental foi de 112 dias, incluindo o período de adaptação. O consumo de matéria seca não foi alterado pelos níveis de CS na dieta com valores médios de 2,51% do peso corporal. A elevação do nível de CS em substituição ao MM resultou em aumento linear do consumo de FDN (1,08; 2,03; 2,92 e 3,78 kg/dia) e redução do consumo de NDT (5,78; 5,16; 5,03 e 5,12 kg/dia) com a inclusão de 0, 33, 66 e 100% de CS em substituição ao MM, respectivamente. O ganho de peso médio diário reduziu linearmente (1,24; 1,11; 1,02 e 0,89 kg/dia), enquanto a conversão alimentar aumentou (6,20; 7,08; 7,77 e 8,67 kg de MS ingerida/kg de GMD) para os níveis de 0, 33, 66 e 100% de CS na dieta, respectivamente. O escore de condição corporal não foi alterado pelos níveis de substituição do MM por CS apresentando valores médios de 3,51 pontos. As medidas corporais de altura não foram influenciadas pelos tratamentos, tanto na garupa quanto na cernelha, apresentando valores médios de 138,5 e 133,25 cm, respectivamente. As medidas de perímetro torácico e comprimento corporal reduziram linearmente, conforme aumentou a inclusão de CS. O peso de abate (PAB) reduziu linearmente apresentando valores de 383,52; 374,71; 363,25 e 366,27 kg para os níveis de 0, 33, 66 e 100% de substituição do MM por CS, respectivamente, entretanto os pesos de carcaça quente (PCQ) ou fria (PCF) não foram alterados pela substituição do MM por CS e apresentaram valores médios de 203,52 e 199,25 kg, respectivamente. Não foi constatado efeito dos tratamentos alimentares sobre o rendimento de carcaça quente que apresentou valores médios de 54,92%. A conformação das carcaças não foi influenciada pela substituição do MM por CS, apresentando valores médios de 9,16 pontos. A espessura de gordura subcutânea (EGS) e a área de olho de lombo (AOL) não foram influenciadas pelos tratamentos alimentares e apresentaram valores médios de 5,3 mm e 53,08 cm2, respectivamente. O rendimento dos cortes primários da carcaça dianteiro, traseiro especial e ponta de agulha não foram alterados pela inclusão de CS e apresentaram valores médios de 36,52; 51,72 e 11,55% da carcaça fria, respectivamente. As medidas objetivas da carcaça não foram influenciadas pelos níveis de substituição do MM por CS. Constatou-se efeito linear decrescente dos tratamentos sobre a compacidade das carcaças apresentando valores médios de 1,56; 1,57; 1,51e 1,45 cm/kg de carcaça fria, para os níveis de 0, 33, 66 e 100% de substituição do MM por CS, respectivamente. A cor e a textura da carne não foram influenciadas pelos tratamentos alimentares e apresentaram valores médios de 3,30 e 3,19 pontos, respectivamente. O marmoreio da carne não foi alterado pela substituição do MM por CS apresentando valores médios 8,56 pontos, com valores de amplitude entre 2 e 17 pontos. A elevação dos pesos de abate resultou em aumento dos pesos da carcaça quente e fria. Animais abatidos com peso superior à 400 kg apresentaram rendimento de carcaça quente de 52,76%, inferior ao grupo de 370-400 kg (56,55%). A EGS não foi influenciada pelos pesos de abate em nenhuma das formas de expressão desta variável, apresentando valores médios de 5,26 mm e 2,67% em relação ao peso da carcaça fria. A AOL aumentou com a elevação dos pesos de abate, sendo a correlação entre estas variáveis de 0,62 (P=0,001) entretanto quando esta variável foi ajustada para 100 kg de carcaça fria esta diferença deixou de existir, apresentando resultados médios de 26,72 cm2 para cada 100 kg de carcaça fria. Os animais abatidos com peso superior a 400 kg apresentaram melhor conformação (9,79 pontos) que os demais grupos experimentais que não diferiram entre si. Verificou-se efeito significativo dos pesos de abate sobre o comprimento das carcaças, perímetro de braço e espessura de coxão que aumentaram 5,9; 2,3 e 3,12 cm, respectivamente, quando elevou-se o peso de abate de <340 à >400 kg. Animais abatidos com peso superior à 400 kg apresentaram maior compacidade das carcaças em relação aos demais tratamentos (1,65 cm de comprimento/kg de carcaça fria). Os pesos absolutos dos cortes primários da carcaça aumentaram conforme elevou-se o peso de abate, entretanto ao ajustar os pesos do dianteiro e do traseiro em relação à 100 kg de carcaça fria, esta diferença deixou de existir, apresentando valores de 36,59 e 51,99%, respectivamente. A cor e textura da carne não foram influenciadas pelos pesos de abate apresentando valores médios de 3,28 e 3,19 pontos, respectivamente. O marmoreio da carne, foi menor no grupo de animais abatidos com peso inferior à 340 kg em comparação ás demais classes de peso que não diferiram entre si. Concluiu-se que apesar de não influenciar as principais características da carcaça, a casca de soja não é eficiente para substituir o milho moído em dietas de alta inclusão de concentrado para novilhas confinadas, pois tem efeito depressivo sobre as principais variáveis de desempenho produtivo, notadamente o ganho em peso e a conversão alimentar. Novilhas de descarte da raça Nelore terminadas em confinamento não devem ser abatidas com peso inferior à 340 kg pois apresentam menor peso de carcaça e menor grau de marmoreio da carne.

A high-precision mixed-signal mismatch measurement technique for metal-oxide metal (MoM) capacitors as well as the design of a 13-GHz 5-bit 360-degree phase shifter are presented. This thesis presents a high-precision, mixed-signal mismatch measurement technique for metal-oxide–metal capacitors. The proposed technique incorporates a switched-capacitor op amp within the measurement circuit to significantly improve the measurement precision while relaxing the resolution requirement on the backend analog-to-digital converter (ADC). The proposed technique is also robust against multiple types of errors. A detailed analysis is presented to quantify the sensitivity improvement of the proposed technique over the conventional one. In addition, this thesis proposes a multiplexing technique to measure a large number of capacitors in a single chip and a new layout to improve matching. A prototype fabricated in 180 nm CMOS technology demonstrates the ability to sense capacitor mismatch standard deviation as low as 0.045% with excellent repeatability, all without the need of a high-resolution ADC. The 13-GHz 5-bit 360-degree phase shifter consists of 2 stages. The first stage utilizes a delay line for 4-bit 180-degree phase shift. A second stage provides 1-bit 180-degree phase shift. The phase shifter includes gain tuning so as to allow a gain variation of less than 1 dB. The design has been fabricated in 180 nm CMOS technology and measurement results show a complete 360◦ phase shift with an average step size of 10.7◦ at 13-GHz. After calibration the phase shifter presented an output gain S21 of 0.5 dB with a gain variation of less than 1 dB across all codes at 13-GHz. The remaining s-parameter testing showed a S22 and S11 below -11 dB and a S12 below -49 dB at 13 GHz.

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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
Two experiments were conducted in Federal Rural University of Pernambuco, the first aimed to evaluate the following parameters: animal performance, intestinal morphology and litter quality of broilers fed diets containing sugar cane yeast (Saccharomyces cerevisiae) dried by "spray-dry" method as prebiotic agent. 350 Cobb 500 male broiler chicks were used, divided into 25 plots (five treatments and five replicates) with 14 birds per plot in a randomized design, from 1 to 42 days old, reared on reused litter, with five treatments: diet without yeast and without antimicrobial growth promoter (AGP), diet without yeast and with 0.04% of AGP (based on zinc bacitracin), diet containing 0.5% yeast and without AGP, diet containing 1.0% yeast without AGP and diet with 1.5% yeast and without AGP. The variables evaluated were: feed intake, body weight, weight gain, feed conversion, villous height, litter depth, ammonia production and poultry litter pH. The intestinal morphology parameters were evaluated at 7 days old and the litter quality parameters were evaluated at 21 and 42 days old. There were no treatment effects observed on animal performance over the periods from 01 to 07 days, from 01 to 21 days and from 01 to 35 days. There were no treatment effects observed on parameters of growth performance in periods of one to seven days, from one to 21 days and up to 35 days. In the period of one to 42 days old, only body weight and weight gain were higher in birds fed diet with 1.5% yeast and without AGP, differing from the diet without yeast and without APC. The height of the villi in theduodenum and jejunum was not affected. The crypt depth was higher in birds that did not receive AGP and yeast and lower for those birds that consumed AGP and yeast and only yeast. The litter quality did not provide data that may represent improvements in the comfort of the animals. On the other hand, the second experimental study had the aim to evaluate the animal performance and carcass yield of broilers fed with diets containing different levels of inclusion of sugar cane yeast (Saccharomyces cerevisiae) by dry rolling. 350 Cobb 500 male broiler chicks were used, divided into 25 plots, with 14 birds per plot, from 1 to 42 days old reared on reused litter. Five treatments were used with 0%, 5%, 10%, 15% and 20% of sugar cane yeast inclusion with five replications in an entirely randomized design. Variables analyzed were: feed intake, body weight, weight gain and feed conversion for the periods from one to seven days, from one to 21 days, from one to 35 days and from one to 42 days old. At 42 days ofxv age, two birds per pen were sacrificed for carcass evaluation on the variables of carcass weight and weight of the cuts: breast, thighs and drumsticks, wings and back. The addition of yeast is not recommended in the diets of broiler chickens in the newly hatched, one to seven days of age, because it had a negative impact on the performance of chicks, showing a decreasing linear behavior for body weight and weight gain variables, as well as an increased linear behavior for feed conversion. Over the period from one to 21 days and from one to 35 days, the diet with 20% yeast showed inferior results than those of diet without yeast while the others did not differ. The level of 20% of yeast inclusion did not affect the animal performance and carcass performance of broiler chickens when the entire rearing period (from one to 42 days old) was considered. The yeast did not affect carcass yield of broilers slaughtered at 42 days old.
Na Universidade Federal Rural de Pernambuco foram conduzidos dois experimentos, o primeiro objetivou avaliar os parâmetros de desempenho zootécnico, da morfologia intestinal e da qualidade da cama de frangos de corte alimentados com ração contendo levedura de cana-de-açúcar (Saccharomyces cerevisiae) seca pelo método “spray-dry”, como agente prebiótico. Utilizou-se 350 pintainhos de corte, machos, da linhagem cobb 500, distribuídos em 25 parcelas (cinco tratamentos e cinco repetições), com 14 animais por parcela, em delineamento inteiramente casualizado, no período de 1 a 42 dias de idade criados em cama reutilizada, com cinco tratamentos: ração sem levedura e sem antimicrobiano promotor de crescimento (APC), ração sem levedura e com 0,04% de APC (à base de bacitracina de zinco), ração com 0,5% de levedura e sem APC, ração com 1,0% de levedura e sem APC e ração com 1,5% de levedura e sem APC. As variáveis de avaliadas foram:consumo de ração, peso corporal, ganho de peso, conversão alimentar, altura dos vilos, profundidade da cama, produção de amônia e pH da cama. Os parâmetros da morfologia intestinal foram avaliados aos sete dias de idade e os de qualidade da cama aos 21 e 42 dias. Não foi observado nenhum efeito dos tratamentos sobre os parâmetros de desempenho zootécnico nos períodos de um a sete dias, de um a 21 dias e de um a 35 dias. No período de um a 42 dias de idade, apenas o peso corporal e o ganho de peso foram maiores nas aves que consumiram ração com1,5% de levedura e sem APC, diferindo da ração sem levedura e sem APC. A altura da vilosidade no duodeno e jejuno não foi influenciada. A profundidade de cripta foi maior nas aves que não receberam APC e levedura e menor para aquelas aves que consumiram APC e levedura e só levedura. A qualidade da cama não apresentou dados que possam representar melhoras no conforto dos animais. Por sua vez, o segundo trabalho experimental teve como objetivo avaliar o desempenho zootécnico e o rendimento de carcaça de frangos de corte alimentados com ração contendo diferentes níveis de inclusão da levedura de cana-de-açúcar (Saccharomyces cerevisiae) seca por rolagem. Foram utilizados 350 pintainhos machos, da linhagem cobb 500, distribuídos em 25 parcelas, com 14 animais por parcela, no período de 1 a 42 dias de idade criados em cama reutilizada. Foram utilizados cinco tratamentos: 0, 5, 10, 15 e 20% de inclusão de levedura de cana-de-açúcar com cinco repetições, num delineamento inteiramente casualizado. Foram analisadas variáveis zootécnicas de consumo de ração, pesocorporal, ganho de peso e conversão alimentar para os períodos de um a sete dias, de um a 21 dias, de um a 35 dias e de um a 42 dias de idade. Aos 42 dias de idade, duas aves de cada parcela foram sacrificadas para avaliação da carcaça, sobre as variáveis de peso da carcaça e peso dos cortes: peito, coxa e sobrecoxa, asa e dorso. A inclusão de levedura não é recomendada nas rações de frangos de corte na fase pré-inicial, de um a sete dias, pois impactou negativamente no desempenho dos pintainhos, com comportamento linear decrescente para as variáveis peso corporal e ganho de peso, bem como, comportamento linear crescente para conversão alimentar. No período de um a 21 dias e de um a 35 dias, a ração com 20% de levedura apresentou resultados inferiores ao da ração sem levedura enquanto que as outras não diferiram. O nível de 20% de inclusão da levedura não afetou o desempenho zootécnico e da carcaça de frangos de corte quando foi considerado o período total de criação, de um a 42 dias de idade. A levedura não afetou o rendimento de carcaça dos frangos de corte abatidos aos 42 dias de idade.

La presente tesis estudia, propone y realiza sus principales aportaciones en el campo del control para el convertidor CC/CA de tres niveles, sobre la topología denominada Neutral-Point-Clamped, aunque se puede extender a otras topologías y/o número de niveles. Se presenta una metodología de modelado que emplea funciones de conmutación de fase, el operador de promediado y la transformación D-Q, tal que los modelos obtenidos en el dominio D-Q contienen una información completa sobre la dinámica del sistema. La estrategia de conmutación se puede entender como una extensión de la estrategia PWM senoidal de dos a tres niveles. Esta estrategia es simple y no realiza el control de ninguna de las variables del sistema. En esta tesis, el controlador se encarga de regular todas las variables del sistema, incluido el equilibrio del bus de continua. Este es un enfoque diferente del convencional, donde el equilibrio del bus de continua se consigue mediante la elección adecuada de los estados redundantes del convertidor en la estrategia de conmutación, mientras que el resto de variables se regulan a través del controlador. Para la realización del controlador, se propone la técnica de control lineal multivariable LQR (Linear Quadratic Regulator), complementada con la técnica de control no lineal adaptativo denominada programación de ganancia (Gain Scheduling). Se presenta, además, una metodología de cálculo del controlador. Este control es versátil, abierto y adaptable. En cualquier caso, el controlador se puede adaptar a las necesidades concretas de cada aplicación. El cálculo del controlador se realiza mediante simulación con MatLab-Simulink. Los modelos matemáticos que emplean las funciones de conmutación del convertidor son aquellos que ofrecen un mejor compromiso entre velocidad de simulación y precisión. Para validar el control propuesto, se ha diseñado y construido un equipo experimental donde el controlador se ha mostrado aplicable, útil y eficaz en la regulación de las distintas cargas y aplicaciones experimentadas, incluso con carga no lineal, bajo diferentes condiciones de trabajo y variables a controlar, tanto en régimen permanente como en procesos transitorios. La rapidez y calidad de la respuesta transitoria es comparable a la de otros sistemas de control publicados. Es especialmente interesante el excelente control conseguido del equilibrio del bus de continua. Además, la robustez del control permite cancelar el error estacionario aunque diferentes parámetros del sistema presenten desviaciones significativas respecto los valores esperados. El uso de la programación de ganancia junto con la técnica LQR se ha mostrado muy efectivo, puesto que permite realizar diferentes tipos de control. Se ha comprobado la congruencia entre simulaciones y resultados experimentales obtenidos, lo que valida los modelos de simulación empleados y el proceso de diseño del controlador mediante simulación.
This dissertation study, propose and carry out the main contributions in the field of three-level inverter control, using the topology Neutral-Point-Clamped, although results can be extended to other topologies and/or number of levels. A procedure for modelling is presented, based on line-switching functions, moving average operator and D-Q transformation. Then, the obtained models in D-Q frame contain complete information about system dynamics. Switching strategy is simple and can be considered as an extension of two-level sinusoidal PWM to three level. The system variables are not controlled by the switching strategy. In this work, all the system variables are controlled by the regulator, including DC-link balance. This control approach is different than the conventional one, where DC-link balance is achieved by means of a proper selection of redundant states in the switching strategy, and the other variables are controlled by the regulator. The regulator is based on the multivariable linear control technique LQR (Linear Quadratic Regulator), in combination with the non-linear adaptive control technique Gain Scheduling. Moreover, a methodology for the calculation of the controller is presented. This controller is versatile, open and adaptable. However, the controller can be built depending on the concrete specifications of each application. The controller is calculated by means of simulation using MatLab-Simulink. The mathematical models based on the switching functions of the converter give the best trade-off between simulation speed and precision. In order to validate the proposed controller, an experimental prototype has been designed and implemented. Experimental results show that the controller is useful and effective for the regulation of different loads and applications, even with non-linear loads, different operation points and variables to control, in steady-state and transitory operation. Dynamic response speed and quality are similar to other control systems in the literature. The DC-link balance control achieved is specially interesting. Furthermore, steady-state error is cancelled due to the robustness of the controller, even though significant deviation of different system parameters are present. The use of Gain-Scheduling in combination with LQR is effective, allowing the calculation of regulators with different control strategies. Good agreement between simulations and experimental results has been found. This result validates simulation models and the design method for the controller, based on simulations.

La presente tesis estudia, propone y realiza sus principales aportaciones en el campo del control para el convertidor CC/CA de tres niveles, sobre la topología denominada Neutral-Point-Clamped, aunque se puede extender a otras topologías y/o número de niveles. Se presenta una metodología de modelado que emplea funciones de conmutación de fase, el operador de promediado y la transformación D-Q, tal que los modelos obtenidos en el dominio D-Q contienen una información completa sobre la dinámica del sistema. La estrategia de conmutación se puede entender como una extensión de la estrategia PWM senoidal de dos a tres niveles. Esta estrategia es simple y no realiza el control de ninguna de las variables del sistema. En esta tesis, el controlador se encarga de regular todas las variables del sistema, incluido el equilibrio del bus de continua. Este es un enfoque diferente del convencional, donde el equilibrio del bus de continua se consigue mediante la elección adecuada de los estados redundantes del convertidor en la estrategia de conmutación, mientras que el resto de variables se regulan a través del controlador. Para la realización del controlador, se propone la técnica de control lineal multivariable LQR (Linear Quadratic Regulator), complementada con la técnica de control no lineal adaptativo denominada programación de ganancia (Gain Scheduling). Se presenta, además, una metodología de cálculo del controlador. Este control es versátil, abierto y adaptable. En cualquier caso, el controlador se puede adaptar a las necesidades concretas de cada aplicación. El cálculo del controlador se realiza mediante simulación con MatLab-Simulink. Los modelos matemáticos que emplean las funciones de conmutación del convertidor son aquellos que ofrecen un mejor compromiso entre velocidad de simulación y precisión. Para validar el control propuesto, se ha diseñado y construido un equipo experimental donde el controlador se ha mostrado aplicable, útil y eficaz en la regulación de las distintas cargas y aplicaciones experimentadas, incluso con carga no lineal, bajo diferentes condiciones de trabajo y variables a controlar, tanto en régimen permanente como en procesos transitorios. La rapidez y calidad de la respuesta transitoria es comparable a la de otros sistemas de control publicados. Es especialmente interesante el excelente control conseguido del equilibrio del bus de continua. Además, la robustez del control permite cancelar el error estacionario aunque diferentes parámetros del sistema presenten desviaciones significativas respecto los valores esperados. El uso de la programación de ganancia junto con la técnica LQR se ha mostrado muy efectivo, puesto que permite realizar diferentes tipos de control. Se ha comprobado la congruencia entre simulaciones y resultados experimentales obtenidos, lo que valida los modelos de simulación empleados y el proceso de diseño del controlador mediante simulación.
This dissertation study, propose and carry out the main contributions in the field of three-level inverter control, using the topology Neutral-Point-Clamped, although results can be extended to other topologies and/or number of levels. A procedure for modelling is presented, based on line-switching functions, moving average operator and D-Q transformation. Then, the obtained models in D-Q frame contain complete information about system dynamics. Switching strategy is simple and can be considered as an extension of two-level sinusoidal PWM to three level. The system variables are not controlled by the switching strategy. In this work, all the system variables are controlled by the regulator, including DC-link balance. This control approach is different than the conventional one, where DC-link balance is achieved by means of a proper selection of redundant states in the switching strategy, and the other variables are controlled by the regulator. The regulator is based on the multivariable linear control technique LQR (Linear Quadratic Regulator), in combination with the non-linear adaptive control technique Gain Scheduling. Moreover, a methodology for the calculation of the controller is presented. This controller is versatile, open and adaptable. However, the controller can be built depending on the concrete specifications of each application. The controller is calculated by means of simulation using MatLab-Simulink. The mathematical models based on the switching functions of the converter give the best trade-off between simulation speed and precision. In order to validate the proposed controller, an experimental prototype has been designed and implemented. Experimental results show that the controller is useful and effective for the regulation of different loads and applications, even with non-linear loads, different operation points and variables to control, in steady-state and transitory operation. Dynamic response speed and quality are similar to other control systems in the literature. The DC-link balance control achieved is specially interesting. Furthermore, steady-state error is cancelled due to the robustness of the controller, even though significant deviation of different system parameters are present. The use of Gain-Scheduling in combination with LQR is effective, allowing the calculation of regulators with different control strategies. Good agreement between simulations and experimental results has been found. This result validates simulation models and the design method for the controller, based on simulations.

Le dé cit cognitif est une cause majeure de handicap de la personne âgée. Du fait de l’augmentation de la durée de vie, le nombre de personnes âgées qui pourraient béné cier d’une prise en charge spécialisée dans le but de ralentir leur perte fonctionnelle va croitre. En dépit de traitement validé qui stoppe le processus neurodégénératif, des interventions spéci ques peuvent en ralentir les manifestations. De nombreuses études expérimentales, neuroscienti ques et comportementales ont démontré la relation étroite entre cognition en motricité.Ce travail doctoral propose d’explorer si certaines caractéristiques de la marche sont des biomarqueurs non-invasifs d’un trouble cognitif et des chutes, et de mieux comprendre les relations entre la cognition et le contrôle de la marche. Le cadre théorique était l’hypothèse de la « Perte de Complexité ». Des analyses multivariées ont été appliquées aux critères de jugement dynamiques de marche en relation avec le statut cognitif-et-chute (Le Chapitre 1).Le Chapitre 2 est une revue systématique de la littérature. Nous avons recensé 20 études longitudinales de prédiction de trouble de la marche et de dé cit cognitif. La vitesse de marche était associée à la cognition, son ralentissement était un prédicteur de la perte cognitive. Cette revue a aussi mis en évidence la nécessité d’améliorer la mesure des phénomènes concernésL’objectif du Chapitre 3 était de déterminer ce qu’apportait l’évaluation cognitive (MMSE, mémoire et fonctions exécutives) et des paramètres dynamiques précis de la marche, au bilan habituel du risque de chute. La précision de la classi cation entre chuteurs et non- chuteurs a augmenté avec l’ajout de la cognition et des paramètres de marche de AUC=0.86 à AUC=0.93. La spéci cité du modèle de classi cation a, quant à elle, augmenté de 60% à 72% avec l’ajout des mesures cognitives, et de 72% à 80% avec l’ajout des paramètres dynamiques de la marche. Dans leur ensemble, ces résultats montrent l’intérêt d’une approche multidimensionnelle incluant l’évaluation des fonctions cognitives et de la marche, dans la prédiction du risque de chute chez la personne âgée.Le Chapitre 4 détermine les paramètres de marche les plus associés au déclin cognitif. La vitesse de marche, la régularité, la prévisibilité et la stabilité ont montré que les simples et doubles-tâches étaient les plus discriminantes (score VIP moyen de 1.12). La marche des patients avec troubles cognitifs est plus lente, moins régulière et moins stable que celle de personnes âgées saines. Cependant, les résultats montrent également que la discrimination des patients âgés avec et sans dé cit cognitif, fondée sur l’exploitation des paramètres de marche uniquement, est faible, avec 57% (simple tâche) et 64% (double-tâche) des patients classés de manière erronée.Le Chapitre 5 présente une étude pilote prospective dans laquelle les paramètres de marche les plus discriminants du Chapitre 4 ont été étudiés. Les résultats ont montré qu’un déclin cognitif signi catif observé après 14.4 mois en moyenne était corrélé avec une marche plus régulière (ρ=0.579*) et plus prévisible (ρ=0.486*) mesurée pendent les mesures de ligne de base, mais pas avec la vitesse de marche de la ligne de base (ρ=0.073). Une augmentationde la régularité et de la prévisibilité de la marche est le re et d’une perte de la complexité de la marche, témoin d’une détérioration future des fonctions cognitives chez les patients âgés.Les résultats de ce travail doctoral sont résumés et discutés dans le Chapitre 6
The rising life expectancy will result in an increased number of ‘older old adults’ who will need specialized geriatric care to slow functional decline. Cognitive impairment is a major cause of disability in geriatric patients. Even though there is no cure yet to reverse neurodegeneration, tailored interventions can slow disease progression and reduce symptoms. Because of the abundant evidence from experimental, neuroscienti c, and behavioral studies that underscored the close link between motor- and cognitive function, the present thesis proposed to use gait characteristics as non-invasive indicators of cognitive impairment and falls in geriatric patients. The main objective therefore was to increase our understanding of the relationship between gait and cognition in this vulnerable population, in which gait outcomes were calculated from 3D-acceleration signals of the lower trunk that were collected with an iPod Touch 4G. The ‘Loss of Complexity’ hypothesis provided a theoretical framework. Multivariate analyses were applied to dynamic gait outcomes in relation to cognitive- and fall-status (Chapter 1).Chapter 2 presents a systematic literature review including 20 longitudinal studies that examined associations between baseline gait function and future cognitive decline. A slow gait speed was associated with future decline in global cognition and in speci c cognitive functions, and with an increased risk for Mild Cognitive Impairment (MCI) and dementia (maximal odds and hazard ratios of 10.4 and 11.1, respectively) in 4.5 years on average. The review projected that future research could increase the speci city of the gait-cognition link by indexing gait and cognition in more detail.From this perspective, Chapter 3 examined whether an extensive cognitive evaluation (global cognition, memory, and executive functioning) and ne-grained, dynamic gait outcomes could add to a usual fall-risk screening. The overall classi cation accuracy of fallers and non-fallers increased from Area Under the Curve (AUC) =0.86 to AUC=0.93. The speci city of the fall-classi cation model increased from 60% to 72% when cognitive outcomes were added, and from 72% up to 80% when gait dynamics were added to the model. The results underscored the need for a multifactorial approach in fall risk assessment in geriatric patients, including a detailed evaluation of cognitive- and gait function.Chapter 4 explored what gait outcomes are most susceptible to change with cognitive decline, and examined multiple gait outcomes in relation to cognitive impairment. Outcomes related to gait speed, regularity, predictability, and stability revealed with the highest discriminative power, indicated by the Variable Importance in Projection (VIP)-values for single- and dual-tasking (average VIP-score of 1.12, with a VIP-score>1 indicating a high discriminative power). Geriatric patients walked slower, less regular, and less stable than healthy old controls. However, the discrimination of geriatric patients with- and without cognitive impairment based on gait outcomes alone was poor, with 57% (single-task) and 64% (dual-task) of the patients being misclassi ed.In Chapter 5, the gait outcomes with the highest discriminative power in chapter 4 were studied in a prospective pilot study. Signi cant cognitive decline (in global cognition, memory, and executive functioning) over 14.4 months on average correlated with a moreregular (ρ=0.579*) and more predictable (ρ=0.486*) gait at baseline, but not with baseline gait speed (ρ=0.073). The increased gait regularity and predictability re ected a loss of gait complexity and this loss of gait complexity may thus predict future cognitive decline in geriatric patients.The results are summarized and discussed in Chapter 6 of this thesis

L’industrie des transports aéronautique et terrestre voit une augmentation constante de l’électrification de ses fonctions. Les actionneurs mécaniques ou hydrauliques sont au fil des évolutions technologiques remplacés par des actionneurs électriques.Les composants qui dominent le marché actuellement ne semblent plus capables de suivre la tendance. En effet, les composants de puissance à base de silicium règnent toujours sur le marché actuel, grâce à leur faible coût. Ce matériau commence par contre à atteindre ses limites théoriques en termes de performances. Dans ce contexte, différentes structures en semi-conducteurs à large bande interdite sont en train d’émerger afin de succéder au silicium.Cette étude a pour objectif d’évaluer la fiabilité des transistors de puissance à base de Nitrure de Gallium. Ces composants semblent être très prometteurs pour des applications moyennes puissances. Cependant, les mécanismes de défaillance dont peuvent souffrir ces composants ne sont pas encore suffisamment étudiés. L’étude consiste en l’application de vieillissements alliant contraintes thermiques et électriques. Ces vieillissements sont effectués à différentes conditions de tension et de température. L’objectif de cette méthode est, dans un premier temps, d’isoler l’effet de chaque facteur de stress sur l’état des composants, et dans un second temps, d’identifier les mécanismes de défaillances activés en fonction des conditions de vieillissement.Ce travail a permis d’identifier l’existence de différents mécanismes de défaillance pouvant être activés selon les conditions de vieillissement. En effet, il est apparu que la gamme de température de vieillissement utilisée influe grandement sur la prédominance des mécanismes de défaillance activés. Les résultats obtenus remettent en question les normes de qualification actuellement appliquées aux composants en Nitrure de Gallium. Ces normes devraient revoir à la hausse les températures de vieillissement utilisées afin de couvrir des gammes plus proches des températures d’utilisation pour ce type de composants
The aeronautical and terrestrial transport industries know a steady increase in the electrification of their functions. In fact, the mechanical or hydraulic actuators are gradually replaced by electric ones.The components dominating the market today seem unable to follow the trend anymore. In fact, silicon-based power components still prevail in the current market, thanks to their low cost. However, this material begins to reach its theoretical limits in terms of performance. In this context, different wide bandgap semiconductor structures are emerging to take on from silicon.The aim of this study is to assess the reliability of power transistors based on Gallium Nitride. These components are very promising for medium power applications. However, the failure mechanisms of these components are not yet sufficiently studied. The study consists in the application of aging tests combining thermal and electrical stresses. These agings are carried out under different conditions of tension and temperature. The objective of this method is, firstly, to isolate the effect of each stressor on the state of the components, and secondly, to identify the failure mechanisms activated according to the aging conditions.This work made it possible to identify the existence of different failure mechanisms that can be activated according to the aging conditions. Indeed, it has emerged that the aging temperature range used influences the predominance of activated failure mechanisms. The results challenge the adequacy of current qualification standards for Gallium Nitride components. These standards should revise upwards the aging temperatures used to cover ranges closer to the operating temperatures of this kind of components

Dans le but de gérer la consommation et ainsi que la production efficace des énergies renouvelables, l’utilisation et augmentation de l’efficacité des systèmes de conversion d’énergie est devenue indispensable. Dans ce contexte, les transistors en nitrure de gallium (GaN HFETs) pour une densité de puissance commutée très importante, offrent des nouvelles possibilités et ils tirent vers le haut la gestion efficace des énergies renouvelables. Toutefois, cette nouvelle possibilité passe par un pilotage efficace des composants et une encapsulation et des interconnexions optimales. Ces travaux de thèse étudient et analyse les avantages et inconvénients d'une nouvelle structure de conversion multi cellulaire et ceux d’un driver spécifique multivoies monolithique et synchronisé pour les composants GaN, appliqué dans ce contexte précis. Ce manuscrit de thèse est composé de quatre chapitres. Après une étude bibliographique, le positionnement du convertisseur DAB (Dual Active Bridge) parmi les autres structures de conversion DC à l’aide d’une nouvelle méthodologie de comparaison (FOM topologique – Figure de Mérite) est présenté dans le premier chapitre. Afin de diminuer les contraintes de conversion d’énergie, une étude est amenée dans le chapitre 2 sur les principaux défis et enjeux d’une solution générique à travers de réalisation d’un réseau de convertisseurs. Le chapitre 3 présente la partie importante d’expérimentation et d’optimisation de la cellule élémentaire à base de convertisseurs DAB des points de vue fonctionnels mais aussi et surtout structurels. L’étude de l’isolation galvanique de la structure de conversion DAB reste l'objectif principal à développer pour démontrer le potentiel de remplacer le transformateur par une isolation capacitive. La conception de la puce de commande dédiée aux nouveaux transistors GaNs, les résultats pratiques des performances sont présentés dans le dernier chapitre. Certaines comparaisons du driver QGD (Quad Gate Driver) avec les autres solutions de transfert d’ordres de commande sont également discutées. La mise en œuvre du circuit de commande dans un convertisseur DAB afin de valider le fonctionnement de QGD est introduite dans les perspectives
In order to improve the management and the production efficiency in renewable energy, power electronics systems have become important contributors. In this context, gallium nitride transistors (GaN HFETs) provide new opportunities for high power density, high switching speed and they pull up the effective management of renewable energies. However, this new opportunity requires effective gate drivers and optimal packaging and assembly. This thesis will introduce the general approach of a new architecture for multi cellular conversion and a monolithic multichannel and synchronized drive for GaN components, which are applicable in our specific context. This thesis is composed of four chapters. A bibliographic section is presented in first chapter. A new comparative methodology has been developed in this chapter in order to benchmark the DAB (Dual Active Bridge) converter with respect to other DC converters. In the second chapter, a generic solution (converter grid) has been explained in order to reduce the energy conversion constraints. Chapter 3 presents the important parts of the experimentation and the optimization of DAB converter. High frequency transformer replacing by capacitors is the main objective of this section. The design of the Quad Gate Driver (QGD) IC dedicated to GaNs transistors control in H bridge configuration and the results of their performances are presented in the last chapter. Some comparisons of this approach with other signal transfer solutions are also discussed. The implementation of the QGD in a full bridge transistor converter is introduced into the perspective section

Ce memoire de these presente une etude theorique et experimentale d'une configuration originale pour la generation de second harmonique et l'amplification parametrique optique dans des guides d'ondes. Nous avons imagine et realise une structure planaire hybride organique/inorganique qui nous permet de realiser l'accord de phase entre des modes guidees d'ordres differents sans qu'il soit necessaire d'introduire une quelconque modulation periodique comme c'est souvent le cas. La structure est donc simple a realiser et de bonne qualite optique. Un polymere non lineaire est depose sur un substrat de verre prealablement modifie en surface par la technique de l'echange d'ions. L'accord de phase intermodal est obtenu entre le mode tm 0 fondamental et un mode tm 1 ou tm 2 harmonique. Nous avons obtenu une efficacite de conversion dans le deuxieme harmonique de = 4. 510 5%/w/cm. La longueur d'onde peut etre accordee sur une large plage en ajustant le temps de diffusion et l'epaisseur de la couche de polymere. L'amplification parametrique optique effective a ete experimentalement obtenue pour une pompe a 532 nm et un signal a 0. 814m. Un gain optique interne de 1db a ete obtenu apres propagation sur 5mm, avec une puissance de pompe de 15kw/mm. Il s'agit la d'un resultat marquant - c'est la premiere fois que l'amplification parametrique optique est observee experimentalement dans un guide polymere - qui montre l'interet de ce type de structure.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
O setor fotovoltaico, devido ao seu grande crescimento nos Ãltimos anos, vem destacando-se significativamente diante de todas as outras fontes de energia renovÃveis e, por isso, tornou-se a terceira maior fonte limpa de geraÃÃo de energia elÃtrica do mundo. No Brasil, esse setor ainda nÃo possui uma relevÃncia na matriz energÃtica devido à tecnologia de conversores e de painÃis ser, na maioria das vezes, toda importada. Considerando a necessidade do desenvolvimento dessa tecnologia, este trabalho vem propor a pesquisa e a implementaÃÃo de um conversor CC/CC de alto ganho aplicado a sistemas fotovoltaicos, que tem como objetivo principal retirar a energia de um mÃdulo fotovoltaico e injetÃ-la em um barramento constante de corrente contÃnua. Um mÃdulo fotovoltaico à conectado na entrada do conversor de alto ganho com tensÃo de saÃda igual a 17 Vcc. Esse conversor eleva a sua tensÃo de entrada e injeta sua corrente de saÃda em um barramento constante de 311 Vcc, utilizando a busca do ponto de mÃxima potÃncia (MPPT). O protÃtipo implementado em laboratÃrio foi desenvolvido para uma potÃncia nominal de 100 W e nÃo possui capacitores eletrolÃticos, aumentando assim o tempo de vida Ãtil do conversor e permitindo incorporar o conversor ao mÃdulo fotovoltaico. O protÃtipo se mostrou robusto e de baixo custo, caracterÃsticas necessÃrias para um conversor aplicado a fontes renovÃveis de energia. O desempenho do protÃtipo, na busca do ponto de mÃxima potÃncia, superou as expectativas do autor, mostrando que um algoritmo bastante simples pode ser extremamente confiÃvel quando se opta pela configuraÃÃo de um conversor por mÃdulo.
The photovoltaic sector has been distinguishing itself from all other renewable energy sources, due to its large growth through the last years. For this reason, it has become the third major clean source of power generation worldwide. In Brazil, this sector still doesnât have great pertinence in the energy matrix, given the imported technology of converters and panels. Considering the demand to develop this technology, this paper propounds the research and implementation of a high gain DC/ DC converter applied to photovoltaic systems, which aims mainly to remove energy from a photovoltaic module and inject it into a DC constant bus. A photovoltaic module is connected to the input of the high gain converter, with an output voltage equals to 17 Vdc. This converter raises its input voltage and injects its output current at a constant 311 Vdc bus, using the maximum power point tracking (MPPT). The laboratory implemented prototype was designed for a rated power of 100W and it doesnât have electrolytic capacitors, thereby increasing the lifetime of the converter and also allowing the incorporation the converter to the photovoltaic module. The prototype had a strong and low cost performance, necessary characteristics for a converter applied to renewable energy sources. The prototype performance exceeded the authorâs expectations, in relation to the maximum power point tracking. Thus, a quite simple algorithm can be extremely reliable when choosing to configure a converter through a module.

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The feed conversion is one of the more indexes monitored by poultry agroindustry, in order to keep their production costs within bounds economically viable. The present study was conducted in order to identify which variables productive have the greatest impact on feed conversion of broilers. Was used production data of poultry agroindustry in the central-west of Brazil. The field results were collected from January 2012 to September 2013, a total of 2,978 broilers flocks. The sample is composed of lots of commercial strains Cobb and Hubbard, not sexed. Was made analysis of variance with Tukey Test (P> 0.05), and analysis of variance in mixed model for the following qualitatives variables: year period, commercial strains, hatchery, incubator type, type of poultry house, homogeneity of flock weight at birth. The correlation and regression polynomial for the following quantitative variables: birth weight, weight to 7, 14, 21, 28, 35, 42 days, weight slaughter, slaughter age, mortality, average daily gain and time interval between flocks on the field. Statistical analysis was made through the statistical program R. The sum of squares in the mixed model, the variables that presented the greatest impact on feed conversion were: period of the year with 39.90%, type of poultry house with 35.70% and lineage with 17.80%. Between quantitative variables that had a greater correlation with the feed conversion ratio is the average daily gain,-0.57 (P < 0.01). Each gram in average daily gain results in nine grams in feed conversion. Flocks that showed lower mortality rate, showed greater correlation between average daily gain and feed conversion. Thus, in the present study, the variables that presented the greatest impact on feed conversion were: average daily gain and period of the year.
O presente trabalho foi realizado com o objetivo de identificar quais variáveis produtivas apresenta maior impacto na conversão alimentar de frangos de corte. Foram utilizados dados de produção de uma agroindústria do centro-oeste do Brasil. Foram coletados resultados de campo no período de janeiro de 2012 a setembro de 2013, totalizando 2.978 lotes de frangos de corte. A amostra era composta de lotes da linhagem Cobb e Hubbard, não sexados. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey (5%). Foi realizada a análise de variância em modelo misto para as seguintes variáveis qualitativas: ano, período do ano, linhagem, incubatório, tipo de incubadora, tipo de aviário e homogeneidade de peso dos lotes ao nascimento. Os dados das variáveis quantitativas: peso ao nascimento, peso aos 7, 14, 21, 28, 35 e 42 dias, peso ao abate, idade de abate, mortalidade, ganho médio diário e tempo de intervalo de lotes foram submetidos à análise de correlação e regressão polinomial. Na soma de quadrados no modelo misto, as variáveis que apresentaram maior impacto na conversão alimentar foram: período do ano com 39,90%, tipo de aviário com 35,70% e linhagem com 17,80%. Entre as variáveis quantitativas a que apresentou maior correlação com a conversão alimentar foi o ganho médio diário, - 0,57 (P<0,01). Cada grama a mais no ganho médio diário resulta em nove gramas a menos na conversão alimentar. Lotes que apresentaram menor taxa de mortalidade, mostraram maior correlação entre ganho médio diário e conversão alimentar. Assim, no presente estudo, as variáveis que apresentaram maior impacto na conversão alimentar foram: ganho médio diário e período do ano.

This paper presents the study and development of a topology of nonisolated converter operating at high frequency, which is suitable for the integration of battery banks, photovoltaic panels, and a high voltage dc link in a single conversion stage. The topology is based on the bidirectional version of the three-state switching cell and is recommended for battery charging, while a 200V dc link can be obtained in a single conversion stage using photovoltaic (PV) panels. The presented converter is able to supply a 200V dc link using a battery bank and a PV array and, depending on the solar irradiance level, it is also possible to charge the batteries by using a single conversion stage. Moreover, all the switches of the converter are able to operate under zero voltage switching (ZVS) condition over a wide operation range. The experimental results are obtained from a 500W laboratory prototype, which has been developed and tested in three situations: energy flow from the battery bank to the load, energy flow from the PV panel to the load; and energy flow from the panel to the battery bank, achieving the efficiency of 94,18%, 96,09% e 94,67% respectively. The high gain afforded by this topology and the excellent performance obtained in all operations mode, shows as a solution where the requirement of increasing the voltage to 200V or 400V from low input voltage energy sources, typically 12V, 24V or 48V, provided by batteries, solar panels or others sources of energy, for Uninterruptable Power Supply (UPS), or a DC link, for example.
Este trabalho tem por escopo apresentar o estudo e desenvolvimento de um conversor CC-CC nÃo isolado de trÃs portas, adequado à integraÃÃo em um Ãnico estÃgio de conversÃo: um banco de baterias, um conjunto de painÃis fotovoltaicos e o link CC. A topologia proposta apresenta um conversor boost de alto ganho baseado na versÃo bidirecional da cÃlula de comutaÃÃo de trÃs estados na qual se tem integrado um banco de baterias e um conjunto de painÃis fotovoltaicos com capacidade para gerar um barramento CC de 200V em um Ãnico estÃgio de processamento. A caracterÃstica bidirecional da topologia permite aos painÃis fotovoltaicos carregar as bateiras e alimentar a carga dependendo da incidÃncia solar. No caso de ausÃncia de sol, o banco de baterias supre a carga. Outra importante caracterÃstica deste conversor à a comutaÃÃo suave em modo ZVS para todas as chaves. Foi desenvolvido um protÃtipo experimental com potÃncia nominal de 500W de forma a validar todo o embasamento teÃrico e de simulaÃÃo apresentados. O conversor desenvolvido foi submetido a trÃs condiÃÃes: o fluxo de energia da bateria para a carga, do painel fotovoltaico para a carga e do painel para o banco de baterias, sendo obtido o rendimento de 94,18%, 96,09% e 94,67% respectivamente para cada condiÃÃo. AlÃm disso, as formas de ondas experimentais e de simulaÃÃo para cada condiÃÃo e o comparativo de rendimento de topologias, tambÃm sÃo apresentados. O alto ganho e o rendimento alcanÃado nesta topologia, a torna uma forte soluÃÃo quando hà necessidade de elevar a tensÃo a partir de baterias ou painÃis fotovoltaicos, quando os valores fornecidos por estes geralmente sÃo de 12V, 24V ou 48V. Ressalte-se que este trabalho contribui cientificamente na Ãrea da eletrÃnica de potÃncia, mais especificamente, no que concerne ao estudo e desenvolvimento de novas topologias de conversores CC-CC nÃo isolados de trÃs portas para aplicaÃÃes em energias renovÃveis.

Dois ensaios experimentais foram conduzidos com o objetivo de determinar o efeito dietético da suplementação de acidificantes sobre o desempenho, incidência de diarréia (ensaio 1) e na digestibilidade aparente de nutrientes (ensaio 2). No ensaio 1, com duração de 42 dias, 120 leitões desmamados aos 21 dias foram distribuídos em 8 blocos experimentais com três leitões por baia,foram aplicados cinco tratamentos. Os tratamentos foram: ração sem acidificante, com 1,0% de diformiato de potássio, com 1,0% de ácido fumárico, com 1,0% de ácido cítrico ou com 1,0% de ácido benzóico. No ensaio 2, 10 leitões com peso médio inicial de 16,4 kg foram distribuídos em dois blocos experimentais, cada um com cinco repetições, sob dois tratamentos (ração sem acidificante ou com 1,0% de ácido fumárico). No estudo de desempenho, a adição de ácido fumárico nas rações determinou aumentos (P<0,05) no consumo de ração nos períodos de 0 aos 15 dias, 0 aos 32 dias e ganho de peso de 0 aos 42 dias, quando comparado ao tratamento controle. Não foi observada a ocorrência de diarréia nos leitões nos primeiros 14 dias pós-desmame. No ensaio 2, a adição de 1,0% de ácido fumárico na ração não alterou (P>0,05) os coeficientes de digestibilidade aparente da matéria seca, proteína bruta e fibra bruta, os valores de energia digestível e metabolizável das rações e a taxa de absorção e retenção de nitrogênio. A ausência de diferenças nos coeficientes de digestibilidade aparente dos nutrientes dietéticos com a inclusão do acidificante, provavelmente, deveu-se ao curto período de avaliação. A inclusão de ácido fumárico nas rações de leitões desmamados favoreceu o desempenho dos leitões.
Two experimental assays were conducted in order to evaluate the effect of supplementation of acidifiers in the diets both on performance traits and incidence of diarrhea (assay 1) and on nutrient digestibility (assay 2). In assay 1, which lasted for 42 d, it was used 120 21-days old weaned piglets, distributed in 8 blocks of 3 pigs per pen. There were five evaluated treatments, which consisted of: ration without acidifier, with 1,0% of K-diformate, 1,0% of fumaric acid, 1,0% of citric acid or 1,0% of benzoic acid. In assay 2, 10 pigs with an average weight of 16,4 kg were allocated in two treatments (ration without acidifier or supplemented with 1,0% of fumaric acid) with five replicates each; experimental design was ramdomized complete blocks. In comparison with the control treatment, the addition of fumaric acid in the ration led to an increase in the following parameters: daily feed intake from day 0 to 15 (P< 0,05); daily feed intake and body weight gain from day 0 to 32 (P< 0,05) and from day 0 to 42 d (P< 0,05). There was not treatment effect (P> 0,05) upon feed conversion over the experimental period, and it was not observed the occurrence of diarrhea over the first 14 days after weaning. In assay 2, the addition of 1,0% of fumaric acid in the ration did not modify (P>0,05) the coefficients of apparent fecal digestibility of dry matter, crude protein and crude fiber, the values of digestible and metabolizable energy of the rations and the rates of nitrogen absorption and retention. The absence of differences in the coefficients of the dietary nutrient s apparent digestibilidade with the inclusion of the acidifier, probably, was due to the short evaluation period. The inclusion of fumaric acid in the rations of weaned pigs improved performance of piglets; however, it did not modify the coefficients of apparent fecal digestibility of the nutrients.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
FundaÃÃo de Amparo à Pesquisa do Estado do CearÃ
A geraÃÃo de energia elÃtrica que combina o desenvolvimento humano com menos impactos ambientais e menos poluiÃÃo à um item fundamental no inÃcio deste sÃculo. Assim, a principal motivaÃÃo da caminhada atual à o desenvolvimento de novas topologias de sistemas descentralizados de fornecimento de energia. O objetivo à desenvolver um conversor bidirecional com alto ganho tensÃo, que à projetado para operar em dois modos: boost e buck. A topologia apresentada permite a transferÃncia bidirecional de energia, o que em algumas situaÃÃes, à transferida para o barramento CC, ou para um banco de baterias. O conversor à projetado para um potÃncia de 2 kW. à apresentado o desenvolvimento teÃrico e experimental do projeto para os dois modos de operaÃÃo. A fim de validar a proposta, sÃo apresentados resultados experimentais, para uma potÃncia de 1 kW. Os resultados foram satisfatÃrios e seu rendimento global de 93%. O protÃtipo foi testado em condiÃÃes diferentes que podem ser encontradas no dia-a-dia.
The achievement of energy generation which combines human development with less environment pollution impact is a key item in the premises of this century. Thus the main motivation of the present walk is the development of new topologies for decentralized supply systems. The objective is to develop a bidirectional converter with high voltage gain, which is designed to operate in two modes: step-up (boost) and step down (buck). The presented topology enables to bidirectional energy transfer, which in some situations it is returned to the load DC bus, formed by a back of batteries. The converter is designed for 2 kW linear load power. If is presented theoretical development and experimental designs for the two operation modes. In order to validate the proposal, it is presented experimental results, from 1 kW laboratory prototype are presented as well and 93% overall efficiency. The prototype was tested in different conditions that may be found daily.

Les lasers à fibre de haute puissance constituent depuis une dizaine d’année un outil pertinent pour un nombre croissant d’applications. Dans le cadre d’un contrat CIFRE entre la société Eolite Systems et le laboratoire Xlim (UMR 7252 du CNRS et de l’Université de Limoges), mon projet de thèse a consisté à développer les briques technologiques de futures sources lasers
High-power fiber lasers adress an increasing number of applications since ten years. In the frame of a CIFRE contract between the company Eolite Systems and Xlim (joint laboratory between CNRS and the University of Limoges), the goal of this PhD project was to develop the technological blocs to achieve all-fibre high-power lasers emiting out of the conventional spectral band covered by existing lasers.Modal instabilities in large mode area (LMA) fibers are currently the main limitation of the fiber lasers power scaling. We have experimentally demonstrated the relevance of inner cladding aperiodic structures to efficiently delocalize higher order modes outside the gain region. A systematic study of passive fibers based on such structures has shown the single propagation of the fundamental mode over a wide wavelength range from 1 to 2 µm for dimension of core up to 85 µm. This effective mode delocalization even extends up to a core dimension of 140 µm at a 2 µm wavelength.The combination of high power picosecond fiber laser with an average power of 22.7 W and a hydrogen-filled inhibited coupling Kagome fiber allowed us to generate two Raman combs over five frequency octaves from 321 nm to 12.5 µm. These two combs are controlled by the laser pump polarization and generated an average power of 10.1 W displayed over 70 laser lines for circular pump polarization and 8.6 W over 30 lines for linear polarization. Some laser lines within these combs have been generated for the first time from high-power fiber source in the mid-infrared range. We have also demonstrated the generation of high-power line by optimizing the first vibrational Stokes at 1.8 µm with an average power of 9.3 W and a quantum efficiency of the frequency conversion stage close to 80%

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Foi conduzido um experimento utilizando-se 630 pintos com um dia de idade com o objetivo de avaliar os efeitos de ácidos orgânicos, frente à inoculação experimental de Salmonella Typhimurium sobre a saúde intestinal, desempenho, bacteriologia de órgãos e função hepática. As aves foram distribuídas em delineamento inteiramente ao acaso com seis tratamentos e sete repetições com 15 pintos cada. O desafio experimental com a bactéria ocorreu por duas vias de administração: via inglúvio, ao primeiro dia após eclosão, e via ração durante o período de sete a 14 dias de idade. Estes grupos foram tratados ou não com ácidos orgânicos, definindo-se desta forma, um esquema fatorial de 3x2 (agente versus ácidos orgânicos). Os pintos dos tratamentos preconizados para inoculação no primeiro dia de vida receberam via inglúvio, a dose de 5,0 x 102 /0,5mL unidades formadoras de colônias (UFC) de Salmonella Typhimurium. Os tratamentos com contaminação via ração, receberam o desafio na dosagem de 5,0 x 102 UFC de Salmonella Typhimurium/ kg de ração. O teste de Tukey (5%) foi utilizado para análises das variáveis. Os grupos tratados com ácidos orgânicos apresentaram melhores de ganho de peso, peso médio e conversão alimentar (p<0,05) aos 14, 21 e de ganho de peso e peso médio (p<0,05) aos 28 dias de idade. Os grupos inoculados com Salmonella Typhimurium apresentaram piores índices de desempenho (p<0,05) aos sete, 14 e 28 dias. O peso do intestino delgado foi maior (p<0,05) para os grupos inoculados quando comparado ao grupo controle, entretanto com comprimento menor para o mesmo fragmento intestinal. O tratamento inoculado via inglúvio e tratado com ácidos orgânicos apresentou menores valores (p<0,05) de unidades formadoras de colônia/g de Escherichia coli em excretas do que os grupos que foi comparado. O pH do conteúdo do conteúdo cecal e do intestino delgado não foi afetado (p>0,05) pela adição de ácido, enquanto o pH do intestino delgado dos grupos inoculados foi menor (p<0,05) quando comparado ao grupo controle negativo durante todo o período experimental. Também foi verificado menor peso (p<0,05) de fígado para os grupos controle negativo aos 21 e 28 dias. Os grupos tratados com ácido, independente da via de administração com Salmonella Typhimurium, obtiveram menores freqüências de isolamento em todos os órgãos analisados. Foram também observadas alterações (p<0,05) na bioquímica sérica hepática e na análise histopatológica do fígado pela atuação da Salmonella. Pode-se concluir que o ácido utilizado na dosagem de 0,4% potencializou o desempenho, foi eficaz no controle de Salmonella Typhimurium e não promoveu lesões hepáticas, quando da inoculação experimental de Salmonella Typhimurium ácido nalidíxico resistente.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This Master Thesis proposes a high gain non-isolated DC-DC converter applied on the processing of PV energy. The proposed converter is a boost converter with quadratic characteristic and with central point at its output. Basic operations and electric characteristics of a PV cell are described, including the procedures to determine its parameters. A model for numeric simulation is presented. A review of the high gain non-isolated DC-DC converters topologies is presented. Shows the converter´s transfer functions and the control strategy adopted as well as the design of control circuits. The control system is consisting of three loops, an internal loop of input current control, an external loop of total output voltage control and an additional loop of voltage unbalance control. The simulation and experimental results are shown to validate the analysis developed and demonstrate the performance of the control system adopted.
Esta Dissertação de Mestrado propõe um conversor CC-CC não isolado de elevado ganho para aplicação no processamento de energia solar fotovoltaica. O conversor proposto é um boost com característica quadrática e com ponto médio na sua saída. Descrevem-se o funcionamento básico e as características elétricas de uma célula fotovoltaica, incluindo-se o procedimento da determinação dos parâmetros e da modelagem dos módulos fotovoltaicos, apresentando-se um modelo para simulação numérica. Apresenta-se uma revisão de topologias de conversores CC-CC não isolados com elevado ganho estáticos. Apresentam-se as funções de transferência do conversor e a estratégia de controle adotada bem como o projeto dos circuitos de controle. O sistema de controle composto por três malhas de controle, uma malha interna de corrente de entrada, uma malha externa de tensão total e uma malha adicional de equalização de tensão. Resultados de simulação e experimentais são apresentados para validar as análises desenvolvidas e demonstrar o desempenho do sistema de controle adotado.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
Este trabalho visa a aplicaÃÃo dos controles robustos D-LQI e D-AlocaÃÃo de polos otimizados via LMIs em um conversor boost de alto ganho de tensÃo com cÃlula de comutaÃÃo de trÃs estados. Este conversor consiste numa topologia moderna derivada do conversor boost clÃssico. O boost à considerado um elevador de tensÃo, o qual converte uma entrada na faixa de 42-54V à 400 V. O conversor boost proposto à reduzido ao modelo de um conversor equivalente e à modelado no espaÃo de estados mÃdio, em que à observado que a matriz D diferente de zero, sendo entÃo uma modelagem que apresenta uma peculiaridade de acordo com a literatura, pois a soluÃÃo de controle à mais complexa. As estratÃgias de controle aplicadas usam de procedimentos matemÃticos denominados de Desigualdades Matriciais Lineares (LMIs-Linear Matrix Inequalities), que podem ser resolvidos por otimizaÃÃo convexa ou programaÃÃo semidefinida positiva (SDP procedures). As ferramentas matemÃticas utilizadas para resoluÃÃo das LMIs neste trabalho sÃo o Yalmip e Sedumi, que sÃo inseridas no MATLAB . AlÃm disso sÃo analisadas as incertezas presentes no processo, bem como a robustez do modelo em malha fechada. SÃo obtidos os resultados de simulaÃÃo via MATLAB -PSIM e sÃo feitas as anÃlises referentes a estes resultados, alÃm da anÃlise dos resultados experimentais e a conclusÃo do estudo, alÃm das propostas de trabalhos futuros. O ApÃndice mostra os procedimentos de instalaÃÃo dos resolvedores alÃm do uso correto com base nas equaÃÃes descritas na teoria sobre LMIs.
This work involves the application of robust controls D-LQI and D-pole placement via LMIs in a high-gain boost with three states switching cell. This converter consists of a modern topology derived the classic boost converter . This boost converter is considered a step-up converter, which a range of 42-54V voltage input to 400V voltage output. The proposed boost converter is reduced to equivalent model and is modeled at space state avarage, in which is observed that the matrix D not equal nought, being then a modeling that presents a peculiarity according to literature, thus the control solution is more complex. The control strategies applied use mathematical procedures called Linear Matrix Inequalities (LMIs), which can be solved by convex optimization or positive semidefinite procedures (SDP). The mathematical tools used to solve the LMIs this work are Yalmip and Sedumi, which are inserted in MATLAB. Further analyzes the uncertainties present in the process, as well as the robustness of closed loop model. The simulation results are obtained via MATLAB and PSIM and analyzes made regarding these results, besides the analysis of experimental results and conclusion of study, in addition to proposals for future work. The Appendix shows the installation procedures and use correct solvers based on the equations described in LMI theory.

Ce travail de thèse a eu pour but de développer des nouvelles sources lasers, oscillateurs et ampli?cateurs, construites autour des ?bres dopées aux ions ytterbium. Ces systèmes lasers génèrent des fortes puissances moyennes. L’oscillateur réalisé délivre des impulsions courtes (<10 ns) avec des énergies de l’ordre du milliJoule. Le système fonctionne à des cadences variables (10-100 kHz) avec un faisceau polarisé, monomode dont la largeur spectrale est inférieure à 0.1 nm. A?n d’avoir de plus fortes puissances crêtes et des impulsions courtes, deux types d’ampli?- cateurs ont été étudiés. Les résultats expérimentaux que nous avons obtenus sont en accord avec le modèle numérique développé. Le premier système ampli?e un microlaser émettant à 1064 nm dans une ?bre dopée ytterbium. Des puissances crêtes supérieures à 500 kW ont été obtenues avec des impulsions de l’ordre de la nanoseconde et une cadence comprise entre 1 kHz et 30 kHz. Le second ampli?cateur est construit autour d’un oscillateur à ?bre dopée ytterbium déclenché injecté dans une deuxième ?bre qui constitue l’ampli?cateur. L’originalité de ce système réside dans le cou- plage de deux cavités. Nous avons alors en sortie deux faisceaux cohérents, polarisés, monomode, indépendamment ajustables en énergie. En?n, nous avons utilisé les sources lasers développées, qui présentent des caractéristiques spec- trales, modales, énergétiques adéquats pour effectuer la conversion de fréquence. Des ef?cacités de l’ordre de 64 % et 38 % ont été atteintes respectivement en doublage et en triplage. Les faisceaux en sortie de ces systèmes possèdent des remarquables caractéristiques spatiales et temporelles
This work presents the development of oscillators and ampli?ers build around new ytterbium rod type ?ber. These ?ber systems generate high average power generation. The oscillator makes it possible to deliver well linearly polarized, almost TEM 00 mode, and millijoule-level nanosecond pulses at a tunable repetition rate (10-100 kHz). The spectral bandwidth was shown to be less than 0.1 nm. To achieve higher peak power and shorter pulses, two types of ampli?ers have been developed and characterized. The experimental results we obtain, do well agree with the numerical simulations we developped. The ?rst system ampli?es in a rod type ?ber the nanosecond pulses yielded by a microlaser working at 1064 nm wavelength injected . Its provides pulses with a high peak power system (500 kW). Its repetition rate was tuned from 1 kHz to 30 kHz. The second ampli?er was built using a Q-switched ytterbium doped ?ber oscillator injected in a second ?ber which acts as ampli?er. In this original system the two cavities are coupled. It delivers two nanosecond pulses that are coherent, polarized, almost TEM00 single mode beams and that can have independently tunable pulse energies. We have shown that these oscillators and ampli?ers can be easily doubled and tripled in fre- quency. Very high ef?ciency of about 64 % and 38 % have been achieved respectively at 2? and 3?. These outputs have been to have remarquable spatial and temporal characteristics

Face aux enjeux énergétiques d’aujourd’hui et de demain, le développement des énergies renouvelables semble inéluctable. Cependant, la production électrique de sources renouvelables prometteuses comme le photovoltaïque ou l’éolien est intermittente et difficilement prévisible du fait de la dépendance de ces sources aux conditions météorologiques. Afin de s’affranchir du caractère discontinu de la production d’électricité et de l’inadéquation de la production avec la consommation, un moyen de stockage de l’énergie électrique est nécessaire. Dans ce contexte, la batterie hydrogène est une des solutions envisagées. Lors de périodes de surproduction d’énergie renouvelable, un électrolyseur produit de l’hydrogène par électrolyse de l’eau. Lorsque cela est nécessaire, une pile à combustible fournit de l’électricité à partir du gaz stocké. Couplé avec des sources d’énergie renouvelable, la batterie hydrogène produit de l’énergie électrique non carbonée, c’est-à-dire non émettrice de gaz à effet de serre. L’intérêt majeur de cette technologie est le découplage entre l’énergie et la puissance du système. Tant que la pile à combustible est alimentée en gaz, elle fournit de l’électricité, l’énergie dépend des réservoirs de gaz. La puissance, quant à elle, dépend des caractéristiques des composants électrochimiques et du dimensionnement des chaînes de conversions de puissance. Les chaînes de conversion de puissance relient les composants électrochimiques au réseau électrique. Dans le cas de la chaîne de conversion sans transformateur qui est ici envisagée, la présence d’un convertisseur DC-DC à haut rendement à fort ratio de conversion est rendue nécessaire de par la caractéristique basse tension fort courant des composants électrochimiques. Avec pour but principal l’optimisation du rendement, deux axes de recherche sont développés. Le premier axe développe un convertisseur multicellulaire innovant à haut rendement à fort ratio de conversion. Les résultats expérimentaux du convertisseur appelé « miroir » obtenus dans deux expérimentations ont démontré la supériorité de cette topologie en terme d’efficacité énergétique par rapport aux convertisseurs conventionnels. Le deuxième axe porte sur de nouveaux composants de puissance en nitrure de gallium (GaN) annoncés comme une rupture technologique. Un convertisseur buck multi-phases illustre les défis technologiques et scientifiques de cette technologie et montre le fort potentiel de ces composants.

Le photovoltaïque terrestre est actuellement largement dominé par des dispositifs à base de Silicium. La limite théorique d’efficacité de photoconversion pour les cellules solaires en silicium est de l’ordre de 29%. Avec des modules photovoltaïques ayant une efficacité de 26.3% sur le marché, la filière Si est à un niveau de maturité avancée et exploite déjà la quasi-totalité du potentiel de ce genre de cellule solaires. Le travail exposé ici traite d’une autre voie d’amélioration de l’efficacité de conversion des dispositifs photovoltaïques. En effet, les cellules solaires tandem, assemblées en empilant plusieurs cellules permettent de dépasser les limites associées aux cellules Si. La complémentarité importante des cellules solaire III-V avec les cellules Si permettrai en théorie d’atteindre plus de 40% d’efficacité. Cette thèse vise à l’élaboration de cellule III-V performante et compatible avec un usage en tandem. Dans un premier temps, l’épitaxie d’alliages phosphures a été étudiée et en particulier l’influence des conditions de croissance sur le GaInP. Une réduction de la pression en phosphore durant la croissance provoque des modulations de composition au sein de l’alliage. La température a un impact significatif sur la valeur de bande interdite qui diminue en augmentant la température. Des caractérisations de photoluminescence ont permis de définir les conditions optimales de croissance en maximisant le signal de luminescence de l’alliage. L’étude a notamment révélé que cru dans les conditions choisies, le GaInP présente moins de défaut et d’états profonds qu’à plus faibles températures de croissance. Enfin la capacité à atteindre des niveaux de dopages élevés dans l’alliage AlGaInP et l’impact de sa composition sur le dopage ont étés étudié. Dans un second temps, la structure des cellules solaires simple jonction GaInP a été optimisée. Nous illustrons l’impact de la passivation de la surface des cellules par AlInP et AlGaInP, ainsi que l’amélioration du photo-courant par l’amincissement de l’émetteur dopé n. L’introduction de couche non-dopée dans la structure ne permit pas de remédier au problème de collection des porteurs constaté dans les cellules. La couche limitant l’efficacité des cellules est composée de p-GaInP. Des caractérisations par Cathodoluminescence et Fluorescence résolue en temps d’échantillons identiques à cette couche ont été menées. Elles ont mis en avant une faible longueur de diffusion des porteurs générés dans le matériau. La comparaison de ces propriétés avec la littérature et celle mesurées pour GaInP épitaxié par MOCVD, indique que l’amélioration de l’efficacité des cellules passe par une augmentation de la mobilité des porteurs au sein du GaInP. Une solution pratique, combinant GaInP et AlGaAs dans une cellule à hétérojonction a été mise en œuvre. Ce type de structure est une autre perspective intéressante à l’avenir puisque des efficacités à l’état de l’art ont été mesurées. Enfin nous avons développé un procédé permettant d’adapter les cellules pour un usage tandem. Les structures sont crues en inversé puis transférées sur verre ou wafer de silicium sans endommager leur performance. Toutefois, des améliorations sont toujours nécessaires pour permettre l’assemblage d’une cellule tandem fonctionnelle. En effet, la non-planéité introduite par les contacts arrières de la cellule III-V cause actuellement des problèmes de collage
Terrestrial photovoltaic is dominated by Silicon based devices. For this type of solar cells, the theory predicts an efficiency limit of 29%. With photovoltaic modules showing 26.6% efficiency already, Silicon-based modules is a mature technology and harvest almost their full potential. In this work, we intend to explore another path toward the enhancement of photovoltaic conversion efficiency. Tandem solar cells that consist in stacking sub-cells, allow to overcome the Si efficiency limit. Since solar cells made of III-V semiconductors are complementary to Silicon solar cells, theory predicts that efficiency above 40% is attainable when combining those types of cells. Here we focus on the elaboration of a performant III-V solar cell, compatible for a tandem use. The first stage of the PhD was to build know-how on phosphide alloys epitaxy with MBE. The influence of the growth conditions on GaInP properties was studied. We noted that composition modulations appear in the alloy when grown with low phosphorus pressure. The growth temperature also impacts the material bandgap, which reduces while increasing the temperature. Photoluminescence characterization served to select the best growth conditions by maximizing the photoluminescence efficiency. We could also highlight that in the conditions chosen, the GaInP exhibits less defect states. AlGaInP alloys are used for passivation purposes in the cells, the influence of the composition of the alloy on the Beryllium doping efficiency was studied. Then GaInP single junction solar cells were fabricated. The different layers composing the cells were optimized. The impact of the front surface passivation with AlGaInP and AlInP was emphasized; improvement of the cell photocurrent by the thinning of the n-doped GaInP layer was also demonstrated. The introduction of a non-intentionally-doped layer in the structure was tested in order to remedy the limits encountered with photocurrent collection. The p-GaInP composing the cells was eventually identified as the limiting factor. In depth characterization of samples mimicking the limiting layer was performed with cathodoluminescence and time-resolved fluorescence. A small diffusion length of the generated carriers was evidenced. Comparison with MOVPE and with literature values suggests that improving the carrier mobility in this layer is the main route to follow for improving of the GaInP cell efficiency. A practical solution was proposed and implemented: we designed a cell combining GaInP and AlGaAs in a heterojunction cell. This structure proves to be very relevant for the project since state of the art photoconversion efficiency of 18.7% was obtained. Finally a process was developed to adapt the III-V solar cells to the tandem configuration. Inverted PV cells structures were grown and transferred on glass or Silicon hosts without degradation of their efficiency. Further improvement of the process is needed to build a full tandem device, in particular the back metallization of the III-V cells must be compatible with the bonding of the cells on the host substrate

Face aux enjeux énergétiques d'aujourd'hui et de demain, le développement des énergies renouvelables semble inéluctable. Cependant, la production électrique de sources renouvelables prometteuses comme le photovoltaïque ou l'éolien est intermittente et difficilement prévisible du fait de la dépendance de ces sources aux conditions météorologiques. Afin de s'affranchir du caractère discontinu de la production d'électricité et de l'inadéquation de la production avec la consommation, un moyen de stockage de l'énergie électrique est nécessaire. Dans ce contexte, la batterie hydrogène est une des solutions envisagées. Lors de périodes de surproduction d'énergie renouvelable, un électrolyseur produit de l'hydrogène par électrolyse de l'eau. Lorsque cela est nécessaire, une pile à combustible fournit de l'électricité à partir du gaz stocké. Couplé avec des sources d'énergie renouvelable, la batterie produit de l'énergie électrique non carbonée, c'est-à-dire non émettrice de gaz à effet de serre. L'intérêt majeur de cette technologie est le découplage entre l'énergie et la puissance du système. Tant que la pile est alimentée en gaz, elle fournit de l'électricité, l'énergie dépend des réservoirs de gaz. La puissance quant à elle, dépend des caractéristiques des composants électrochimiques et du dimensionnement des chaînes de conversions de puissance. Les chaînes de conversions de puissance relient les composants électrochimiques au réseau électrique. Dans le cas de la chaîne de conversion sans transformateur qui est envisagée ici, la présence d'un convertisseur DC-DC à haut rendement est rendue nécessaire de par la caractéristique basse tension fort courant des composants électrochimiques. Avec pour but principal l'optimisation du rendement, deux axes de recherches sont développés. Le premier axe de recherche développe un convertisseur multicellulaire innovant à haut rendement à fort ratio de conversion. Les résultats expérimentaux du convertisseur appelé 'miroir' obtenu dans deux expérimentations ont démontré la supériorité de cette topologie en terme d'efficacité énergétique par rapport aux convertisseurs conventionnels. Le deuxième axe de recherche porte sur de nouveaux composants de puissance au nitrure de gallium (GaN) annoncés comme une rupture technologique. Un convertisseur buck multi-phases illustre les défis technologique et scientifique de cette technologie et montre le fort potentiel de ces composants.

Ces dernières années, la consommation énergétique n’a cessé de s’accroitre. Pour contrer cela, les systèmes de conversion électrique se doivent d’être plus performants, d’améliorer les rendements tout en limitant l’encombrement des systèmes, réduisant ainsi les matières premières utilisées. Parmi les systèmes de conversion efficaces, le correcteur du facteur de puissance et sa diode "boost" assurent un rendement de conversion d’environ 95 %. Ces travaux de thèse s’intéressent à la réalisation de ce type de diode en utilisant un matériau différent du traditionnel silicium, le nitrure de gallium (GaN), ce qui pourrait permettre d’atteindre des rendements de conversion supérieurs à 98 %. Le GaN est épitaxié sur Si et des diodes Schottky sont réalisées à sa surface. Des protocoles expérimentaux ont été mis en place en vue d’optimiser leurs performances, notamment la réduction des densités de courant de fuite
These past few years, energy consumption has continued to increase. To counter this, the power conversion systems need to be more efficient, to improve yields while limiting systems volume, which reduce raw materials. Among efficient conversion systems, the power factor corrector and its "boost diode" provide a conversion efficiency of about 95%. This work concerned with the realization of this type of diode using a different material from the traditional silicon, the gallium nitride (GaN), which could allow higher conversion efficiencies of 98% to be achieved. GaN is grown up on Si and Schottky diodes are made on its surface. Experimental protocols were implemented in order to optimize their performance, especially the reduction of leakage current densities. Two research areas were defined: surface treatments and the realization of the guard ring. Our results showed that the different surface preparations either by wet or plasma can reduce leakage current

In this thesis I present a study of nanowires, and, in particular, I apply EBIC microscopy for investigation of their electro-optical properties. First, I describe details of the EBIC analytical technique together with a brief historical overview of the electron microscopy, the physical principles of the EBIC, its space resolution, parameters defining the signal amplitude, and the information we can acquire concerning defects, electric fields, etc. Then I focus on the characterization of LEDs based on GaN nanowires, which were analyzed in a cross-section and in a top view configurations. The EBIC measurements were correlated with micro-electroluminescence mapping. Further, I address the fabrication and measurement of nanowire-based InGaN/GaN LEDs detached from their original substrate. I present the EBIC measurements of individual nanowires either cut from their substrate and contacted in a planar geometry or kept standing on supphire substrate and cleaved to reveal the horizontal cross-section.The next part of this thesis is dedicated to an EBIC study of irregular Si nanowire array-based solar cells, and then of the regular nanowire array devices. The current generation was analyzed on a submicrometer scale. Finally, I discuss the fabrication and EBIC measurements of GaN nanowires grown on Si substrate. In particular, I show that the p-n junction was induced in the Si substrate by Al atom diffusion during the nanowire growth
Dans cette thèse je me propose d’étudier des nano-fils, et en particulier d’utiliser la technique EBIC pour explorer leurs propriétés électro-optiques. Je décris d’abord les détails de la technique d’analyse EBIC avec un bref retour historique sur la microscopie électronique, le principe physique de l’EBIC, sa résolution spatiale, les paramètres conditionnant l’amplitude du signal, et les informations que l’on peut en tirer sur le matériau en termes de défauts, champ électrique, etc. Je m’intéresse ensuite à la caractérisation de LEDs à nano-fils à base de GaN, qui ont été observés par EBIC, soit en coupe soit en vue plane (depuis le haut des fils). Les mesures EBIC sont comparées à celles de micro-électroluminescence. Plus loin j’adresse la fabrication et la mesure de nano-fils à base de GaN séparés de leur substrat d’origine. Je présente les mesures EBIC de nano-fils uniques entiers, puis de nano-fils en coupe horizontale.La partie suivante de la thèse traite d’étude EBIC des cellules solaires à base de nano-fils Si ayant d’abord une géométrie aléatoire, puis une géométrie régulière. La génération de courant dans ces cellules solaires est analysée à l’échelle submicronique. A la fin du manuscrit je discute la fabrication et les mesures EBIC de fils GaN épitaxiés sur Si. Je montre en particulier qu’une jonction p-n est enduite dans le substrat Si par la diffusion d’Al lors de la croissance de nanofils

碩士
國立彰化師範大學
積體電路設計研究所
97
In this thesis designed two chips, a highly integrate dual-band mixer for WiMAX/UWB receiver systems and a mixer for UWB receiver systems are designed. The first chip is high conversion gain mixer with active balun for UWB and WiMAX system. We employ the current injection technique and dynamic current to increase conversion gain. Then we use LC filter to decrease noise figure. In order to CIC measure systems not provide output 20MHz balun, hence IF port used active balun to differentials signal conversion single signal. The chip achieved 16.9 ~ 19.7 dB measured conversion gain for 1.8 V supply voltage. The total power consumption is 25.2mW. The second chip is a folded mixer that can cover 2 ~ 11GHz WiMAX system. In order to obtain wide-band input property, we use a RLC matching network. We also use folded topology to achieve low noise figure. Finally, we use Source Buffer to let IF’s return loss be less then －10 dB. The mixers is simulated by Agilgent EDA (Electronic Design Automatic) - ADS (Advance Design System) with TSMC 0.18 μm RF CMOS technology.

碩士
長庚大學
電機工程學研究所
96
In this thesis, a gain scheduling perturbation and observation (P&O) algorithm is proposed to realize the dynamic and rapid maximum power point tracking (MPPT) for a grid-connected photovoltaic energy conversion system (PECS). The hardware implementation of the PECS consists of a 1.5kW (at 500V) monocrystalline silicon photovoltaic (PV) array and a voltage-sourced inverter (VSI) whereby an IGBT-based intelligent power module is applied. In order to reach MPPT, the reference DC-link voltage of the VSI is generated by a command generator based on conventional P&O algorithm. To further improve the performance of the PECS under various daylight irradiations, the control gains for command generator are scheduled according to the gradient of electrical characteristic of the PV array exposed to a daylight irradiation. In contrast to the use of the MPPT algorithm in electrical power conversion, the reactive power compensation is also feasible to improve the power factor for the grid utility under low daylight irradiation and thus increases the facility utilization significantly. The experimental results show that the proposed PECS with gain scheduling P&O algorithm is capable of tracking maximum power point and compensating the reactive power for the grid utility.