Дисертації з теми "Transition voltage"
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Choi, Jae-Young. "Analysis of Inductor-Coupled Zero-Voltage-Transition Converters." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/28537.
Повний текст джерелаPh. D.
Ambatipudi, Ravindra. "Modeling and control of zero-voltage transition three-phase PWM boost rectifier." Thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-06162009-063557/.
Повний текст джерелаNose, Masafumi. "Studies on Sodium-containing Transition Metal Phosphates for Sodium-ion Batteries." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215565.
Повний текст джерелаSpitzig, Alyson. "The importance of Joule heating on the voltage-triggered insulator-to-metal transition in VO₂." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/62808.
Повний текст джерелаScience, Faculty of
Physics and Astronomy, Department of
Graduate
Cuadros, O. Carlos E. "Modified Space Vector Modulation for a Zero-Voltage Transition Three-Phase to DC Bi-directional Converter." Thesis, Virginia Tech, 1995. http://hdl.handle.net/10919/36712.
Повний текст джерелаMaster of Science
Wu, T. H. "Optimising cell voltage and understanding charge storage mechanism of transition metal oxides and hydroxides for aqueous supercapacitors." Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3002214/.
Повний текст джерелаPowers, Alex D. "A Study of Constant Voltage Anemometry Frequency Response." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1570.
Повний текст джерелаRicoeur, Guillaume. "Caractérisations électriques et analyse de la méthode "Transition Voltage Spectroscopy" sur les jonctions moléculaires à base de molécules alkyles." Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10091/document.
Повний текст джерелаWe assess the performances of the transition voltage spectroscopy (TVS) method to determine the energies of the molecular orbitals involved in the electronic transport (barrier height) through molecular junctions (electrode-molecule-electrode). For this, we made a large number of molecular junctions with electrodes of various shapes (drop, tip, layer) and various metals (gold, aluminum, mercury, gallium-indium). We use for the molecule part of the molecular jonctions self-assembled monolayers (SAMs) made with various alkyl molecules. We show that the transition voltages obtained by TVS for molecular junctions without oxide at the interfaces electrode / molecule correspond to the tail of the density of states of the molecular orbitals, and not to the top of the density of states. This result was obtained by comparing the TVS results with UPS and IPES measurements performed on the same SAM. In the case of molecular junctions with at least one electrode/molecule interface oxidized, we show that the transition voltage corresponds to the energy level of the oxide at the interface and not to the molecular orbital of the SAM. We validated this hypothesis with reference measurements on junctions without SAM. We also compared the TVS with other methods e.g. the Simmons model, and we studied the influence on TVS of various parameters: loading force by C-AFM, junction asymmetry/symmetry and molecule length
Weerasinghe, Hasitha C. "Electrical characterization of metal-to-insulator transition in iron silicide thin films on sillicone substrates." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001677.
Повний текст джерелаJacquet, Quentin. "Li-rich Li3MO4 model compounds for deciphering capacity and voltage aspects in anionic redox materials." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS332.
Повний текст джерелаGlobal warming, due to the increasing CO2 concentration in the atmosphere, is a major issue of the 21th century, hence the need to move towards the use of renewable energies and the development of electrical storage devices, such as Li-ion batteries. Along that line, a new electrode material called Li-rich NMCs have been developed, having higher capacity, 290 mAh/g, than commercial materials, like LiCoO2 (150 mAh/g), thanks to participation of oxygen anions into the redox reaction. This process, called anionic redox, unfortunately comes with voltage hysteresis preventing the commercialization of Li-rich NMC. To alleviate this issue while increasing the capacity, fundamental understanding on anionic redox is needed, specifically concerning two points: is anionic redox limited in terms of capacity? And what is the origin of the voltage hysteresis? In a first part, with the aim to assess the limit of anionic redox capacity, we designed new compounds, having enhanced oxygen oxidation behavior, belonging to the A3MO4 family (A being Li or Na and with M a mix of Ru, Ir, Nb, Sb or Ta). We performed their synthesis, deeply characterized their structure, and, by studying their charge compensation mechanism, we showed that anionic redox is always limited by either O2 release or metal dissolution. In a second part, we designed two new materials, Li1.3Ni0.27Ta0.43O2 and Li1.3Mn0.4Ta0.3O2, having different voltage hysteresis, in order to identify the origin of this phenomenon. Coupling spectroscopic techniques with theoretical calculations, we suggest that the electronic structure, namely the size of the charge transfer band gap, plays a decisive role in voltage hysteresis
Bon, Emeline. "Implication de la sous-unité B4 des canaux sodiques dépendants du voltage dans l'invasivité des cellules cancéreuses mammaires et régulation de son expression par l'acide docosahexaènoïque." Thesis, Tours, 2015. http://www.theses.fr/2015TOUR3310/document.
Повний текст джерелаThe loss of voltage gated sodium channel NaVβ4 subunit expression in breast cancer biopsies is associated with high grade tumors and metastatic development. The inhibition of β4 expression in MDA-MB-231 breast cancer cells enhanced their invasiveness by two fold. During this thesis, we have shown that β4 underexpression promotes mesenchymal-amoeboid transition and increases NaV-independent invasion. This transition is characterized by rounded morphology, the presence of blebs at the cell surface and an increased RhoAGTPase activity. This transition is inhibited by β4 C-terminal intracellular domain overexpression. Expression of β4 can be enhanced by a DHA supplementation that increases the encoding SCN4B promoter activity. DHA also increases β4 expression through the modulation of PPARs lipid-sensitive nuclear receptors expression
Dong, Wei. "Analysis and Evaluation of Soft-switching Inverter Techniques in Electric Vehicle Applications." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/28859.
Повний текст джерелаPh. D.
Murphy, Ryan. "Development of an Autonomous Single-Point Calibration for a Constant Voltage Hot-Wire Anemometer." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1357.
Повний текст джерелаBoukadoum, Redouane. "Étude des décharges partielles et de leur transition à l’arc dans la connectique aéronautique du futur." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLC019/document.
Повний текст джерелаThe objective of the more electrical aircraft project is the replacement certain of the hydraulic and pneumatic systems by electrical ones. This drastic technological transition will require the increase of the onboard electrical power, which will result in the increase of voltage levels of the embedded networks. Current systems of 28 VDC and 115 VAC (400 Hz) are to be replaced by +/- 270 VDC and 230 VAC (360 to 1000 Hz). These new conditions of voltage levels will have a significant impact on the appearance of partial discharges that were almost absent up until present. Aeronautical grade electrical connectors being one of the major elements of embedded networks, the aim of this thesis is to study the conditions of occurrence of partial discharges in them. In this work, electrostatic modeling is carried out in order to identify the zones within the connectors where there is a strong electric field facilitating the appearance of partial discharges. Also presented are the results of experiments under both DC and AC voltage in which the ignition voltages of partial discharges and their location within the structure of the connector were studied
Oliveira, Antônio Wanderley de. "Transporte de portadores minoritários que justificam o regime de ressonância eletrônica em sistemas de carbynes." Universidade Federal do Pará, 2016. http://hdl.handle.net/11612/469.
Повний текст джерелаOne of the goals for the expansion of knowledge in molecular electronics may be found in the Project related to the creation of nanoscale circuits based on nonlinear current–voltage characteristics composed by molecules connected to metallic electrodes under the action of an external electric field. The development of molecular electronic devices using systems exhibiting similar feature as intrinsic semiconductor materials is one of the goals to be achieved by an extensive research in nanotechnology. Thus, this work aims at expanding of knowledge not only of the electronic transport, but also the physical features that justify the resonant regime for electronic transport, such as conductance and Transition Voltage Spectroscopy. We theoretically investigate the electronic charge transport in a molecular system composed by carbyne structures taking into account the variations in the bonds −≡− type (simple and triple bonds for each carbon). Ab initio calculations approximations are performed to investigate the distribution of electron states over the molecule in the presence of an external electric field. This new nanoelectronic device raise up advantage for the design of large 1D hybrid organic/metallic circuits with an increased electronic flow that is importante for the needs of nanotechnology.
Kinn, M. C. "An analysis of the sociotechnical transition process from the existing centralised alternating current voltage electrical system in the UK to one where distributed direct current voltage is used to meet the energy needs of the built environment." Thesis, University of Salford, 2016. http://usir.salford.ac.uk/40962/.
Повний текст джерелаJarecki, Brian W. "GATING OF THE SENSORY NEURONAL VOLTAGE-GATED SODIUM CHANNEL NAv1.7: ANALYSIS OF THE ROLE OF D3 AND D4 / S4-S5 LINKERS IN TRANSITION TO AN INACTIVATED STATE." Thesis, Connect to resource online, 2010. http://hdl.handle.net/1805/2119.
Повний текст джерелаTitle from screen (viewed on April 1, 2010). Department of Pharmacology and Toxicology, Indiana University-Purdue University Indianapolis (IUPUI). Advisor(s): Theodore R. Cummins, Grant D. Nicol, Gerry S. Oxford, Andy Hudmon, John H. Schild. Includes vitae. Includes bibliographical references (leaves 232-266).
Yu, Huijie. "Driver Based Soft Switch for Pulse-Width-Modulated Power Converters." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/26399.
Повний текст джерелаPh. D.
Albrecht, Martin. "Enabling socio-technical transitions – electric vehicles and high voltage electricity grids as focal points of low emission futures." Licentiate thesis, KTH, Miljöstrategisk analys (fms), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206973.
Повний текст джерелаQC 20170512
Norstrat
Clements, Joseph Shelby II. "Synthesis of Insecticidal Mono- and Diacylhydrazines for Disruption of K+ Voltage-Gated Channels, and Elucidation of Regiochemistry and Conformational Isomerism by NMR Spectroscopy and Computation." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/77918.
Повний текст джерелаPh. D.
Appel, Daniel. "Optimalizácia návrhu spínaného regulovateľného DC-DC konvertora." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-242181.
Повний текст джерелаHering, Maria. "Überschlagsverhalten von Gas-Feststoff-Isoliersystemen unter Gleichspannungsbelastung." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200879.
Повний текст джерелаDC operated gas-insulated systems combine the demand for space saving installations and lowloss energy transport over long distances for applications of recent energy transmission. In order to ensure a reliable and safe operation, the behaviour of the gas-solid insulation, which is used in the technological system, has to be known up to the limits of the insulation properties. Hence, this thesis deals with the flashover behaviour of gas-solid insulation systems under DC voltage stress. Thereby, it focuses on two main influence factors: the temperature, due to real current heat losses, and an adhesive defect on the gas-solid interface, due to metallic particles that cannot be fully excluded in practice. Firstly, it is investigated experimentally in two test arrangements, how each parameter separately affects the electrical field distribution, the surface and volume charge accumulation and the insulation performance under DC voltage stress. Following that, their interaction and mutual influence is analysed in the whole system. Due to operating currents, the heating of the conductors in gas-insulated systems causes an inhomogeneous temperature distribution, that affects the properties of the insulating materials gas and epoxy resin. The temperature-dependent conductivity of the solid insulators leads to a temperature-dependent field distribution. Thereby, the location of the highest field strength is shifted. Since the absolute value of the highest field strength can increase, the insulation performance can decrease. Simultaneously, the insulating gas close to the heated conductor locally has a lower gas density and therefore a lower dielectric strength. The thermal related reduction of the insulation performance under DC voltage stress amounts to (25 ... 35) % in the investigated arrangement. Metallic particles, with a length of more than three millimetres and adhering on spacers, turn out to be particularly critical in the weakly inhomogeneous field of gas-insulated systems. At pressures below 0,3 MPa, partial discharges at the particle tips partly ignite already at 50 %of the breakdown voltage without a particle. The corona stabilisation leads to a relatively high flashover voltage. However, due to these stable glow discharges under DC voltage stress, the defect can not be unequivocally proven by usual detection methods. Above 0,3 MPa, no partial discharges occur before the flashover. Due to the missing corona stabilisation, with a higher gas pressure, the insulation strength is not or only disproportionately low increasing. The findings gained with the model arrangement are evidently applicable to spacers of commercial installations. The flashover behaviour of gas-solid insulation systems under DC voltage stress, examined in this thesis, is influenced significantly by the temperature distribution and adhesive particles on the interface. Surface and volume charges change the generally resistive-capacitive described behaviour of the insulation system under DC and superimposed voltage stress. The influence of additional charge carriers on the strongly temperature-dependent field transition demonstrates, that in this case, the insulating gas with its drift and diffusion processes, depending on the particle density and the field strength, has to be considered, when modelling the transient behaviour of DC operated systems. Investigating the system behaviour to the limits of the insulation properties is a crucial element of developing innovative technologies of the modern energy transmission at increasing transmissions powers
Girbino, Michael James. "Detecting Distribution-Level Voltage Anomalies by Monitoring State Transitions in Voltage Regulation Control Systems." Case Western Reserve University School of Graduate Studies / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1550483383962611.
Повний текст джерелаRivera-Hernandez, Margarita. "Scanning tunnelling microscopy studies of liquid crystals." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389236.
Повний текст джерелаNdoye, Mamadou Mustapha. "Contribution à l'étude du transistor bipolaire hyperfréquence sur puce de silicium." Bordeaux 1, 1997. http://www.theses.fr/1997BOR10682.
Повний текст джерелаThis work is a contribution to the study of the high-speed bipolar transistor on silicon chip. First, it presents two original methods allowing to reduce the Base-Collector extrinsic Capacitance, to increase the Base-Collector breakdown voltage, to increase the Voltage Early VA, to increase the maximum power gain Gpmax and to increase the transition frequency FT. Then, it presents a new transistor, hybrid structure between the vertical NPN and the lateral NPN, named bipolar-CLEV (lateral collector-vertical emitter). This study can be generalized to other high speed transistor technologies such as III-V substrate transistors or heterojunction transistors
Festin, Örjan. "On the Zero and Low Field Vortex Dynamics : An Experimental Study of Type-II Superconductors." Doctoral thesis, Uppsala University, Department of Engineering Sciences, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3907.
Повний текст джерелаDynamic properties of type-II superconductors have been experimentally studied in zero and low magnetic fields using SQUID magnetometry and I–V measurements.
In zero magnetic field close to the critical temperature, the physical properties of type-II superconductors are dominated by spontaneously created vortices. In three dimensions (3D) such vortices take the form of vortex loops and in two dimensions (2D) as vortex-antivortex pairs.
The 2D vortex dynamics has been probed using mutual inductance and flux noise measurements on YBa2Cu3O7 (YBCO) and MgB2 thin films in zero and low magnetic fields. In such measurements, information about vortex correlations is obtained through a temperature dependent characteristic frequency, below (above) which the vortex movements are uncorrelated (correlated). The results obtained in zero magnetic field indicate that sample heterogeneities influence the vortex physics and hinder the divergence of the vortex-antivortex correlation length.
In low magnetic fields the vortex dynamics is strongly dependent on the applied magnetic field and a power law dependence of the characteristic frequency with respect to the magnetic field is observed. The results indicate that there is a co-existence of thermally and field generated vortices.
The I–V characteristics of untwinned YBCO single crystals show that only a small broadening of the transition region influences the length scale over which the vortex movements are correlated. The dynamic and static critical exponents therefore exhibit values being larger in magnitude as compared to values predicted by relevant theoretical models. The results also suggest that the copper oxide planes in YBCO decouple slightly below the mean field critical temperature and hence, the system has a crossover from 3D to 2D behaviour as the temperature is increased.
From temperature dependent DC-magnetisation measurements performed on untwinned YBCO single crystals in weak applied fields, detailed information about the critical current density and the irreversibility line is obtained.
Carbonell, Cortés Carla. "Customizing a low temperature system for microwave transmission measurements. Quantum transport in thin TiN films and nanostructures." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/83635.
Повний текст джерелаEl treball que es presenta en aquesta tesi consta de dues parts ben diferenciades. La primera pretén el desenvolupament d’un equip experimental concebut per a l’estudi de propietats magnètiques i elèctriques en materials diversos i, en especial, el treball amb radiació de microones en condicions de reflexió i transmissió. La segona s’ha centrat en les mesures de transport d’una capa fina superconductora de nitrur de titani (TiN) de 5 nm de gruix en un criòstat de dilució.
Masoud, Khalid Hasan. "Circuits and controls for grid-connected inverters." Thesis, Queensland University of Technology, 2002.
Знайти повний текст джерелаGürlek, Akif. "Zum Entladungsprozess der Spitze-Spitze-Elektrodenanordnung bei standardisierter und oszillierender Blitzspannung." Universitätsverlag Chemnitz, 2020. https://monarch.qucosa.de/id/qucosa%3A73246.
Повний текст джерелаThis thesis is dedicated to the acquisition, identification and description of discharge processes, which occur under lightning impulse voltage. A measuring system has been developed that records the electrical and optical parameters of the discharge processes with a high sensitivity and synchronization accuracy on a rod-rod electrode arrangement under standardised and oscillated lightning impulse voltage. With the current measurements and the photographic records of discharges, three phases of the breakdown process can be identified. In order of their occurrence these are the streamer phase, the channel transition phase and the channel formation phase. These phases are shown for the standardised and oscillated lightning impulse voltage, whereby similarities and differences are presented in detail. Using statistical descriptions of the breakdown and the discharge behaviour, dependencies in the discharge process will be derived.
Magnan, Romain. "Oxyde transparent conducteur de ZnO : V à partir d'une cible de nanoparticules : de l’ablation par laser pulsé à un procédé de décharge à barrière diélectrique double fréquence à pression atmosphérique Transparent and conductive vanadium doped zinc oxide thin films by pulsed laser deposition from different targets Atmospheric pressure dual RF-LF frequency discharge: Influence of LF voltage amplitude on the RF discharge behavior Atmospheric pressure dual RF-LF frequency discharge: transition from α to α-γ-mode". Thesis, Perpignan, 2020. http://www.theses.fr/2020PERP0008.
Повний текст джерелаThis thesis jointly supervised by France and Canada aims to develop an innovative method for the development of thin nanocomposite layers of ZnO: V, based on the sputtering and deposition of ZnO: V nanoparticles (NPs) using Double Frequency Dielectric Barrier Discharges (DBDs). This deposition method aims to reduce the cost of production by using nanoparticles synthesized by the sol-gel method and DBD in a configuration allowing the deposition of thin films continuously at atmospheric pressure. The work took place in three phases:- The study of TCO obtained by pulsed laser deposition from a target of NPs of ZnO: V (1% at.) and metal targets of ZnV. The lowest resistivity (4 x 10-4 Ω.cm) is observed for the deposits made at 250 ° C from a Zn: V target (3% at.) While the best optical properties are those of a quasi-amorphous thin layer obtained at 20 ° C from the NPs target of ZnO: V. These thin films have a transmission of 40% in UV at 250 nm, 90% in the visible and 80% in the PIR at 2500 nm) with a resistivity of 6 x 10-2 Ω.cm.- Research and optimization of a DBD plasma source to sputter ZnO: V NPs in a configuration compatible with the deposition of controlled thin films. The approach consisted in increase the flow and energy of the ions at the cathode by applying, on one of the electrodes, a radiofrequency voltage (5 MHz) which generates a high density of ions (~ 2 x 1011 / cm3) and on the other electrode a low frequency voltage (50 kHz) in order to transport the ions to the cathode. The first step was to understand the physics of the DBD RF-BF by coupling the optical characterization of the discharge and the 1D fluid modeling. When the LF voltage increases, the initially RF discharge in the α regime switches to the α-γ regime for 1/5 of the LF cycle. The results show that in γ regime the discharge is self-sustaining in the sheath and the flow of ions at the cathode is multiplied by a factor of 7 while their energy increases by a factor of 4. The experimental study shows that when an NPs target interacts with an RF-BF DBD, NPs are brought into flight.- The design and testing of a DBD reactor configuration comprising 2 successive plasma zones: the first to launch the NPs of a target, the second to deposit the NPs on a substrate. The latter is based on a double frequency BF-LF DBD obtained by applying a 50 kHz voltage which generates electrons to charge the NPs and a 1 kHz voltage which we know can ensure the transport of charged NPs from the volume to surfaces. The feasibility was shown by the observation of NPs on the substrate
Duffiet, Marie. "Compréhension des mécanismes structuraux limitant les performances de LiCoO2 à haut potentiel dans des batteries Li-ion et optimisations des matériaux par dopage Al." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0083.
Повний текст джерелаLithium cobalt oxide (LCO) is widely used as positive electrode material for Li-ion batteries. In order to achieve higher energy density, significant improvement of LCO’s packing density has been recently done by controlling the particles morphology and electrode processing. However, the upper charge cutoff voltage of LCO has barely changed, and would be a way to further enhance the energy density.In this PhD, we focus first in a careful preparation of different LCO samples with an accurate control of the Li stoichiometry (1.00 ≤ Li/Co ≤ 1.04) and particles size to characterize their electrochemical properties. For some selected samples, we study the phase transition mechanisms involved at high voltage during Li de intercalation using in situ synchrotron X-ray diffraction (SXRD): more phase transitions than previously reported have been evidenced for the stoichiometric LCO (Li/Co = 1.00) charged up to 5.2 V. In particular, while the formation of the H1 3 and O1 phases is confirmed, intermediate intergrowth structures are also stabilized. The existence of defects in overlithiated LCO (Li/Co > 1.00) does not hinder, but delay the formation of the high voltage of H1 3 and O1 phases, although structurally modified.In a second part, we focus on the material optimization though 4% Al-doping using a solid state route. Several compounds were prepared using various Li/(Al+Co) stoichiometries, with different particles sizes. Our efforts were dedicated to accurately characterize the Al doping homogeneity in the samples that affects the electrochemical properties. Using SXRD and 7Li, 27Al and 59Co MAS NMR as complementary tools, we show that homogeneous Al-doping in stoichiometric LCO can be achieved using Li-excess in a first step of the synthesis followed by a stoichiometry readjustment to Li/(Co+Al) = 1.00
Fortes, Carmen Beatriz Borges. "Caracterização e propriedades das resinas acrílicas de uso odontológico : um enfoque voltado para a biossegurança." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2007. http://hdl.handle.net/10183/11014.
Повний текст джерелаBrazil, similar to other countries, is aging quickly. The individuals with more than 60 years old compose today the segment that more grows in proportional terms, showing an increment of about 500% in 40 years. The estimate for 2020 is that Brazil has around 32 million elderly and a significant parcel of them will be partial or totally toothless, needing prosthetic equipments. In spite of notable scientific advance in the rehabilitation of the oral health, many people still will use these equipments. The continuous use of the prosthesis can propitiate the development of denture stomatitis, whose etiology is multifactorial, being generally, associated to the presence of fungus Candida albicans. Bad oral hygiene and prosthesis is still distinguished as factor of risk. Therefore, it very necessary for the elderly a efficient, safe and easy handling method of disinfection with low occupational risk and that doesn’t intervene with the properties of the materials used in the confection of these prosthetic equipments. The aim of this work is to evaluate the influence of two disinfection methods on the properties of acrylic resin used in the confection of dental prosthesis. Samples had been confectioned in accordance with the requirements of each test for the control groups (without treatment), as for the treated (submitted to one of the disinfection process). The evaluated properties had been resistance and module of flexure, Izod impact, Knoop microhardness, rugosity, specific mass and degree of swelling, degree of conversion of monomer, glass transition temperature, sorption and solubility. The treatments of disinfection had consisted of: a) irradiation with energy of microwaves, in the power of 840 W, during 1 min, or b) immersion in peracetic acid during 5 min. The effectiveness of the disinfection was evaluated by means of microbiological tests, in which was verified the occurrence of growth of Candida albicans through of culture and sample surface. For that, the samples were previously contaminated with one type of fungus (known as ATCC 10231) and, after, submitted to one of the two considered processes of disinfection. The work was studied the behavior of three commercial acrylic resins of dental use: acrylic resins of thermal polymerization, self-polymerization and polymerization for energy of microwaves (type 1, 2 and 5 respectively) from two different suppliers The results had shown that the acrylic resins of type 1 and type 5 presented similar values in all the analyzed properties. The acrylic resins of type 2 had also similar values in all the properties, but statistically lower than ones of type 1 and 5. The best polymerization cycle, which did not modify the resin properties, was that one considered by the respective manufacturer of the acrylic resin. The nylon fiber presence and colouring did not influence the properties of the acrylic resin of type 5. The first irradiation with microwaves significantlyincreased the evaluated properties and the first immersion in peracetic acid did not modify these properties, in comparison to the control groups. After 20 months, the immersion in peracetic acid did not modify the properties of the material, while the microwave irradiation showed alterations in some properties. Both disinfection techniques had been efficient of the microbiological point of view. On the basis of these results, can be concluded that the microwave irradiation after the polymerization of the material (first cycle), can be recommended, since it increased all the values of the evaluated properties, specially to the conversion degree monomer/polymer. Nevertheless, for prolonged use, the disinfection by means of the immersion in peracetic acid must be recommended, it is efficient for elimination of fungal microorganism and security, characterized for the maintenance of the properties of the acrylic resin evaluated in this work.
Rocha, Pedro Paulo Forain. "Modelo de dimensionamento de frota de helicópteros para um sistema de distribuição física de pessoas voltado às atividades offshore de exploração de produção de uma bacia petrolífera." Florianópolis, SC, 2001. http://repositorio.ufsc.br/xmlui/handle/123456789/81545.
Повний текст джерелаMade available in DSpace on 2012-10-19T05:20:43Z (GMT). No. of bitstreams: 0Bitstream added on 2014-09-26T00:33:57Z : No. of bitstreams: 1 185513.pdf: 8688527 bytes, checksum: d3d89a75a0fc6b0cbbe2cc97841ae4d4 (MD5)
O presente trabalho consiste no desenvolvimento de um modelo matemático de dimensionamento de frota de helicópteros, compatível com um sistema de distribuição física de pessoas e adequado à utilização no planejamento de frota voltada ao atendimento às atividades offshore de exploração e produção de uma bacia petrolífera.
Even, Raymond. "Les premiers semiconducteurs moleculaires : les derives radicalaires des phtalocyanines." Paris 6, 1987. http://www.theses.fr/1987PA066161.
Повний текст джерелаLefebvre, Solène. "Applications de la fluorescence pour la caractérisation structurale et dynamique d'intermédiaires conformationnels des récepteurs-canaux pentamériques." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS207.
Повний текст джерелаPentameric ligand-gated ion channels (pLGICs) are membrane proteins found in both eukaryotes such as the glycine and serotonin receptors and in some prokaryotes like GLIC. In Humans, these receptors are involved in fast synaptic transmission and are a major therapeutic target for general anesthetics or anxiolytics and their mutation lead to severe diseases such as myasthenia, epilepsies or rare neurological diseases like hyperekplexia. Agonist binding on these receptors promote structural reorganizations leading to the active state with an open pore allowing ion flux. Structural and functional properties of these receptors have been studied and combined in this work to explore conformational dynamics of pLGICs. Several approaches have been used to: 1) determine pre-activation kinetics of GLIC at the hundreds of milliseconds timescale, 2) measure the effect of mutations deeply impacting global reorganizations highlighting the major role of allosteric coupling of different protein domains to permit its activation, 3) characterize intermediate states of eukaryotic pLGICs upstream activation. Combined to structural analysis, fluorescence data obtained provide detailed description of conformational intermediates of pLGICs activation and deepen the knowledge of molecular mechanisms determining normal and pathological functioning of these receptors
Mallangi, Siva Sai Reddy. "Low-Power Policies Based on DVFS for the MUSEIC v2 System-on-Chip." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-229443.
Повний текст джерелаNuförtiden så har multifunktionella bärbara hälsoenheter fått en betydande roll. Dessa enheter drivs vanligtvis av batterier och är därför begränsade av batteritiden (från ett par timmar till ett par veckor beroende på tillämpningen). På senaste tiden har det framkommit att dessa enheter som används vid en fast spänning och frekvens kan användas vid flera spänningar och frekvenser. Genom att byta till lägre spänning och frekvens på grund av effektbehov så kan enheterna få enorma fördelar när det kommer till energibesparing. Dynamisk skalning av spänning och frekvens-tekniker (såkallad Dynamic Voltage and Frequency Scaling, DVFS) har visat sig vara användbara i detta sammanhang för en effektiv avvägning mellan energi och beteende. Hos Imec så använder sig bärbara enheter av den internt utvecklade MUSEIC v2 (Multi Sensor Integrated circuit version 2.0). Systemet är optimerat för effektiv och korrekt insamling, bearbetning och överföring av data från flera (hälso) sensorer. MUSEIC v2 har begränsad möjlighet att styra spänningen och frekvensen dynamiskt. I detta examensarbete undersöker vi hur traditionella DVFS-tekniker kan appliceras på MUSEIC v2. Experiment utfördes för att ta reda på de optimala effektlägena och för att effektivt kunna styra och även skala upp matningsspänningen och frekvensen. Eftersom att ”overhead” skapades vid växling av spänning och frekvens gjordes också en övergångsanalys. Realtidsoch icke-realtidskalkyler genomfördes baserat på dessa tekniker och resultaten sammanställdes och analyserades. I denna process granskades flera toppmoderna schemaläggningsalgoritmer och skalningstekniker för att hitta en lämplig teknik. Genom att använda vår föreslagna skalningsteknikimplementering har vi uppnått 86,95% effektreduktion i jämförelse med det konventionella sättet att MUSEIC v2-chipets processor arbetar med en fast spänning och frekvens. Tekniker som inkluderar lätt sömn och djupt sömnläge studerades och implementerades, vilket testade systemets förmåga att tillgodose DPM-tekniker (Dynamic Power Management) som kan uppnå ännu större fördelar. En ny metod för att genomföra den djupa sömnmekanismen föreslogs också och enligt erhållna resultat så kan den ge upp till 71,54% lägre energiförbrukning jämfört med det traditionella sättet att implementera djupt sömnläge.
Calamba, Katherine. "Phase stability and defect structures in (Ti1-x,Alx)Ny hard coatings." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0322.
Повний текст джерелаThis study highlights the role of nitrogen vacancies and defect structures in engineering hard coatings with enhanced phase stability and mechanical properties for high temperature applications. Titanium aluminum nitride (Ti,Al)N based materials in the form of thin coatings has remained as an outstanding choice for protection of metal cutting tools due to its superior oxidation resistance and high-temperature wear resistance. High-temperature spinodal decomposition of metastable (Ti,Al)N into coherent c-TiN and c-AlN nm-sized domains results in high hardness at elevated temperatures. Even higher thermal input leads to transformation of c-AlN to w-AlN, which is detrimental to the mechanical properties of the coating. One mean to delay this transformation is to introduce nitrogen vacancies. In this thesis, I show that by combining a reduction of the overall N-content of the c-(Ti,Al)Ny (y < 1) coating with a low substrate bias voltage during cathodic arc deposition an even more pronounced delay of the c-AlN to w-AlN phase transformation is achieved. Under such condition, age hardening is retained until 1100 °C, which is the highest temperature reported for (Ti,Al)N films. During cutting operations, the wear mechanism of the cathodic-arc-deposited c-(Ti0.52Al0.48)Ny with N-contents of y = 0.92, 0.87, and 0.75 films are influenced by the interplay of nitrogen vacancies, microstructure, and chemical reactions with the workpiece material. The y = 0.75 coating contains the highest number of macroparticles and has an inhomogeneous microstructure after machining, which lower its flank and crater wear resistance. Age hardening of the y = 0.92 sample causes its superior flank wear resistance while the dense structure of the y = 0.87 sample prevents chemical wear that results in excellent crater wear resistance. Heteroepitaxial c-(Ti1-x,Alx)Ny (y = 0.92, 0.79, and0.67) films were grown on MgO(001) and (111) substrates using magnetron putter deposition to examine the details of their defect structures during spinodal decomposition. At 900 °C, the films decompose to form coherent c-AlN- and c-TiN- rich domains with elongated shape along the elastically soft <001> direction. Deformation maps show that most strains occur near the interface of the segregated domains and inside the c-TiN domains. Dislocations favorably aggregate in c-TiN rather than c-AlN because the later has stronger directionality of covalent chemical bonds. At elevated temperature, the domain size of (001) and (111)- oriented c-(Ti,Al)Ny films increases with the nitrogen content. This indicates that there is a delay in coarsening due to the presence of more N vacancies in the film. The structural and functional properties (Ti1-x,Alx)Ny are also influenced by its Al content (x). TiN and (Ti1-x,Alx)Ny (y = 1, x = 0.63 and x = 0.77) thin films were grown on MgO(111) substrates using magnetron sputtering technique. Both TiN and Ti0.27Al0.63N films are single crystals with cubic structure. (Ti0.23,Al0.77)N film has epitaxial cubic structure only in the first few atomic layers then it transitions to an epitaxial wurtzite layer, with an orientation relationship of c-(Ti0.23,Al0.77)N(111)[1-10]ǀǀw-(Ti0.23,Al0.77)N(0001)[11-20]. The w-(Ti0.23,Al0.77)N shows phase separation of coherent nm-sized domains with varying chemical composition during growth. After annealing at high temperature, the domains in w-(Ti0.23,Al0.77)N have coarsened. The domains in w-(Ti0.23,Al0.77)N are smaller compared to the domains in c-(Ti0.27,Al0.63)N film that has undergone spinodal decomposition. The results that emerged from this thesis are of great importance in the cutting tool industry and also in the microelectronics industry, because the layers examined have properties that are well suited for diffusion barriers
Chen, Ming-Ren, and 陳明仁. "Interleaved Flyback Converter with Zero-Voltage-Transition." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/62814697601088122192.
Повний текст джерела國立東華大學
電機工程學系
97
This paper proposes a novel interleaved flyback converter which is composed of two parallel-operated basic flyback converters in addition to an auxiliary inductor and two snubber circuits. This circuit is able to transfer higher power at a much higher efficiency than conventional flyback converters. There are two efficiency boosting features in this proposed circuit. First, both the active power switches are zero- voltage-switched and therefore the switching losses are reduced. Second, the reverse recovery losss on the rectifying diodes are reduced. This is because of the auxiliary inductor which makes the diode currents smoothly ramp down to zero instead of abruptly turn off. The two basic flyback converters are identical, which makes operation analysis and circuit design simpler. A test circuit is built and the experimental result shows satisfactory agreement to the theoretical analysis. The experimental results show that this proposed converter promotes its conversion efficiency up to 91%.
Hsieh, Bing-Hao, and 謝秉浩. "Battery Charger with Zero-Voltage-Transition Boost Converter." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/tzy778.
Повний текст джерела崑山科技大學
電機工程研究所
97
Since traditional hard-switching power switch components have non-ideal characteristics, a voltage surge or current surge generated under conduction and cutoff, the power switch components reduces the efficiency, increases the component stress and facilitates breakage. This work employs soft-switching technology to realize a novel battery charger with a zero-voltage-transition (ZVT) boost converter which increases the charging efficiency above, reduces the switching losses below, and reduces the electromagnetic interference (EMI) below, those of battery chargers with conventional boost converters. The optimal circuit parameters are set based on circuit analyses under the conduction and cut-off conditions of two active switches using equivalent circuits and the circuit operation equations. Experimental results demonstrate the theoretical effectiveness of the proposed battery charger. The practical mean charging efficiency of the developed battery charger is as high as 88.2%.
Hsueh, Te-Chin, and 薛德欽. "High-Efficiency Interleaved Boost Converter with Zero-Voltage Transition." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/77u9y3.
Повний текст джерела國立東華大學
電機工程學系
96
This thesis proposes a high-efficiency interleaved boost converter with zero-voltage transition, which is composed of two shunted elementary boost converters and an auxiliary inductor. This converter is able to turn on both the active power switches at zero voltages to reduce their switching losses and evidently raise the conversion efficiency. Since the two parallel-operated elementary boost converters are identical, operation analysis and design for the converter module becomes quite simple. A laboratorial test circuit is built and the circuit operation shows satisfactory agreement to the theoretical analysis. The experimental results show that this converter module performs very well with the output efficiency as high as 95%.
Lin, Syuan-Li, and 林軒立. "Analysis of the Zero-Voltage Transition PWM Boost Converter." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/y6gnjj.
Повний текст джерела國立臺灣海洋大學
電機工程學系
102
The purpose of this thesis is to analyze a new Zero-Voltage Transition PWM Boost Converter. The converter operates with an active snubber cell, which provides main switch to turn ON with zero-voltage transition (ZVT) and to turn OFF with zero-current transition (ZCT). Furthermore, all semiconductor devices of this converter operate with soft switching at high frequency. The structure of this converter is simple and easy to control. The operation principle and steady-state analysis of the novel boost converter are presented. Finally, the converter feature is proved by simulation.
Chen, Yu-Jen, and 陳妤甄. "An Interleaved Twin-Buck Converter with Zero-Voltage-Transition." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/r465zf.
Повний текст джерела國立中山大學
電機工程學系研究所
97
A twin-buck converter with zero-voltage-transition (ZVT) is proposed in this thesis. The converter comprises two identical buck conversion units connected in parallel by an interleaved inductor. The ZVT is accomplished by the resonating the currents between the interleaved inductor and the parasitic capacitances of the power MOSFETs. The circuit efficiency can be further improved by introducing synchronous rectification to reduce the condition loss on the diodes. The detailed circuit analysis and operation characteristics are provided. A laboratory circuit rated at 300 W is designed and tested. Experimental results show that the switching losses can be effectively reduced by smoothly transiting the currents of the active power switches.
ChenMu-Shi and 陳木禧. "Zero Voltage Transition Pulse-Widith-Modulated Boost Converter for Chargers." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/89458817054810528918.
Повний текст джерела崑山科技大學
電機工程研究所
95
This thesis realizes a zero-voltage-transition pulse-width-modulated boost battery charger for reducing switching losses caused by the switch to enhance the charging efficiency of battery charger. The main switch in the presented battery charger is conducted under zero-voltage condition and the boost diode is cut off under zero-current condition. The switching operation of the switch is completed under the occurrence of resonance condition. The developed battery charger with soft-switching technology has higher efficiency, lower stress on the switch and lower electro-magnetic interference (EMI) over the battery charger with traditional boost converter. This thesis employs the pulse-width-modulated control mode for the switching of two active switches. The operation modes of the circuit and the equivalent circuits are constructed by analyzing the operating principles of the circuit, based on the turn-on conditions of the active switches. The equations used to determine the circuit parameters are derived from the equivalent circuits. Experimental results have demonstrated the theoretical effectiveness of the developed battery charger circuit. The practical mean charging efficiency of the developed battery charger is 91.25%.
Jyh-Herng, Chou, and 周志恆. "Zero Voltage Transition Technology Applied To AC/DC Motor Drives." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/50698877426770441160.
Повний текст джерела國立雲林科技大學
電機工程技術研究所
86
Zero-Voltage-Transition techniques which combine PWM with the soft-switching characteristics make all semiconductor devices be operated at constant frequency. ZVT structure also has very low voltage and current stress and the soft-switching characteristic of the rectifier diode. Therefore, ZVT converters have the minimum conduction loss. This thesis will analyze and discuss the characteristics of the ZVT-PWM technique applied to the dc and ac motor drives. First, the effects of switching frequency and duty cycle on efficiency,speed characteristics and ripple current of the various dc motor are investig ated. Comparison of ZVT-PWM converter-fed dc motor with the traditional hard-switching PWM topology shows the ZVT-PWM converter-fed dc motor can reduce switching loss, ripple current and improve the efficiency even the load variation is very large. In tradition, the hard-switching inverter applied to the three phase induction motor is subject to high switching loss and consequently reduces the performance and efficiency of the inverter system. Therefore, This thesis applied a new type of Parallel Resonant DC Link ﹙PRDCL﹚topology which can provide the zero voltage switching of switches of the inverter and minimize the peak voltage stress of the switches. In addition, The Space Voltage Vector Pulse-Width-Modulation }SVPWM﹚strategy is applied to the inverter. It can reduce the voltage and current harmonics in the inverter output and consequently provide the operation of induction motor smoothly. Digital Signal Processor TM S320C14﹙T.I.﹚is used to implement the SVPWM strategy. Experimental results show that the new PRDCL combines with SVPWM can reduce the switching loss and the current harmonic. The structure can also minimize the voltage stresses and improve the efficiency while it is applied to induction motor drives system.
Su, Ding-Tsair, and 蘇丁財. "Design and Implementation of Zero-Voltage-Transition Boost Power Factor Corrector." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/52781086863305326926.
Повний текст джерела國立雲林科技大學
電機工程系碩士班
91
The purpose of this thesis is to design and implement a high performance single- phase power factor corrector. A zero-voltage-transition (ZVT) boost power factor correction converter features high power factor, high efficiency, and low harmonics line current. The trend in switching power converter is towards increasingly higher power densities. This thesis proposes a ZVT power factor corrector operating at 100kHz and using an average current mode control. The main power stage components experience no more voltage or current stress than normal, the switch and diode both experience soft switching transitions. The results suggest that the soft switching transitions not only reduce the switching losses significantly, but also reduce electromagnetic interference. The operation principle was described in detail for different operating modes and their respective equivalent circuit and design method were also discussed. A ZVT boost power factor correction circuit capable for an output power 750W was designed and verified by PSpice simulation. The feasibility of the proposed control is confirmed through experimental results.
Hsieh, Ying-Tsai, and 謝英材. "A Study of Optimizing the manufacturing Process for Transition Voltage Regulator." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/57106895598142059505.
Повний текст джерела臺北城市科技大學
嵌入式系統產業研發碩士專班
100
Embedded systems, electronic components can basically be divided into passive components and active components. Resistor belongs to the passive components which you can use its resistance value to adjust the size of the circuit elements. The regulator in the manufacturing process will be generated the failure of the automatically sporadic selected electrical resistance. This results in poor transition voltage or defective goods. We must spend hours to maintenance. After several times to find the real reason is still unable to prevent the transition voltage or defective goods. In order to further investigate the configuration of the components used by the basic line and seek a stable voltage variation, we use the extension method to find the best solution. I hope to take advantage of the matter element extension to establish the correlation function. The synchronous rectification technology can effectively reduce the conduction losses caused by the rectifier diodes. We use the embedded microprocessor to adjust the output of the function, design a high efficiency, low electromagnetic interference, and the output of the quasi-harmonic flyback converter, and enhance the efficiency of immense benefit. This method can select the optimal process to improve efficiency and product yield rate, and thus increase productivity and reduce production cost.
Leu, Yau-Jiun, and 呂堯君. "Implementation and Design of Buck Zero-Voltage-Transition Pulse- Width-Modulated Converter." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/82257249551270227796.
Повний текст джерела大同工學院
電機工程研究所
81
In this thesis , a comprehensive analysis of the buck zero- voltage-transition (ZVT) pulse-width-modulated (PWM) coverter is presented . Both active and passive switches achieve zero- voltage switching without significantly increasing their voltage and current stresses . Due operation under the constant frequency , the optimization of the circuit is easily attainable . A novel control approach is introduced . The approach is simple and provides switches with switching. Using results of the dc analysis and dc conversion ratios, a design procedure with the switching property is proposed , and is used to build prototype circuit operating at the switching frequency 296KHz . It has been proven useful for design and when the ZVT PWM converter is implemented at higher frequencies.
Chen, Chuen-Shiu, and 陳春旭. "The design of zero-voltage-transition(ZVT) power factor correction(PFC) circuit." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/16706264659421257343.
Повний текст джерелаChou, Po-Han, and 周柏翰. "Sliding-Mode Control on an Interleaved Boost Converter with Zero-Voltage Transition." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/83388771928931374001.
Повний текст джерела國立東華大學
電機工程學系
99
The objective of this thesis is to develop and implement a control algorithm applying frequency-modulation based sliding mode control (SMC) for a novel interleaved boost converter with zero-voltage transition. It is well known that the major advantage of SMC is its insensitivity upon parameter variations and/or external disturbances. Once the system state reaches and keeps on the sliding surface, neither parameter variation nor disturbance will sway the system out of the stable state. In this thesis, output voltage error is embraced into the sliding function, and then equivalent control force is derived, such that the system state trajectory is forced toward the sliding surface and converges to a stable operation point. Moreover, the approaching condition is proven that the system will reach sliding surface within a limited time period. SMC algorithm here guarantees the stability of the output voltage of the interleaved boost converter even if load variation and external load disturbance exist. The proposed sliding mode control is implemented in a 32-bit fixed-point DSP controller. Finally, experimental results are illustrated to show the validity of the proposed sliding mode control algorithm.
Liu, Yung-Hiang, and 劉永祥. "Design and Implementation of a Zero-Voltage-Transition Boost Power Factor Correction Circuit." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/44608802976964266381.
Повний текст джерела國立交通大學
電機與控制工程系
87
This thesis presents the design and implementation of a zero-voltage-transition power factor correction (PFC) converter having high power factor, low harmonic line current, high efficiency, and high switching frequency. Conventional boost zero-voltage-transition with auxiliary switches can reduce switching loss, however, the hard switching of the auxiliary switches can significantly increase additional switching losses. Soft switching techniques can be applied to these auxiliary switches to reduce the switching losses. By using zero-voltage-transition techniques, a lossless snubber circuit has been developed to reduce the switching losses of the auxiliary switch. The operational principle and equivalent circuits of the proposed zero-voltage-transition converter are analyzed in detail. In addition, a systematic design procedure has been given to design the converter. Computer simulation using Ispice has been carried out in analyzing the proposed zero-voltage-transition soft-switching PFC scheme. A 3kW, 200kHz prototype of the boost zero-voltage-transition PFC converter has been constructed. Experimental results can verify the efficiency improvement and EMI reduction by the proposed soft-switching PFC scheme.