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1
Örn, Fredrik. "Computer Vision for Camera Trap Footage : Comparing classification with object detection." Thesis, Uppsala universitet, Avdelningen för visuell information och interaktion, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-447482.
Abstract:
Monitoring wildlife is of great interest to ecologists and is arguably even more important in the Arctic, the region in focus for the research network INTERACT, where the effects of climate change are greater than on the rest of the planet. This master thesis studies how artificial intelligence (AI) and computer vision can be used together with camera traps to achieve an effective way to monitor populations. The study uses an image data set, containing both humans and animals. The images were taken by camera traps from ECN Cairngorms, a station in the INTERACT network. The goal of the project is to classify these images into one of three categories: "Empty", "Animal" and "Human". Three different methods are compared, a DenseNet201 classifier, a YOLOv3 object detector, and the pre-trained MegaDetector, developed by Microsoft. No sufficient results were achieved with the classifier, but YOLOv3 performed well on human detection, with an average precision (AP) of 0.8 on both training and validation data. The animal detections for YOLOv3 did not reach an as high AP and this was likely because of the smaller amount of training examples. The best results were achieved by MegaDetector in combination with an added method to determine if the detected animals were dogs, reaching an average precision of 0.85 for animals and 0.99 for humans. This is the method that is recommended for future use, but there is potential to improve all the models and reach even more impressive results.Teknisk-naturvetenskapliga
2
Murray, Jacolin Ann. "High Flow Air Sampling for Field Detection Using Gas Chromatography-Mass Spectrometry." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2414.
Abstract:
The ability to rapidly detect and identify hazardous analytes in the field has become increasingly important. One of the most important analytical detection methods in the field is gas chromatography-mass spectrometry (GC-MS). In this work, a hand-portable GC-MS system is described that contains a miniature toroidal ion trap mass analyzer and a low thermal mass GC. The system is self-contained within the dimensions of 47 x 36 x 18 cm and weighs less than 13 kg. Because the instrument has a small footprint, it was used as the detector for an automated near-real-time permeation testing system. In permeation testing, materials that are used to make individual protective equipment such as gloves, masks, boots, and suits are exposed to hazardous analytes to determine how long the equipment can be worn safely. The system described herein could test five samples simultaneously. A multi-position valve rotated among the various sample streams and delivered time aliquots into the MS for quantitation. Current field air sampling techniques suffer from long desorption times, high pressure drops, artifact formation and water retention. These disadvantages can be avoided by concentrating the analytes in short open tubular traps containing thick films. There are several advantages to using polymer coated capillaries as traps, including fast desorption, inertness and low flow restriction. An air sampling trap was constructed utilizing open tubular traps for the concentration of semi-volatile organic compounds. The system consisted of multiple capillary traps bundled together, providing high sample flow rates. The analytes were desorbed from the multi-capillary bundle and refocused in a secondary trap. The simultaneous focusing and separation effect of a trap subjected to a negative temperature gradient was also explored. In this configuration, analytes were focused because the front of the peak was at a lower temperature than the rear of the peak and, hence, moved slower. In addition to the focusing effect, analytes with different volatilities focused at different temperatures within the gradient, allowing for separation.
3
Sudholz, Ashlee. "Machine learning for the automated detection of deer in drone and camera trap imagery." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/212981/1/Ashlee_Sudholz_Thesis.pdf.
Abstract:
To effectively manage the growing population of invasive deer in Australia, adequate monitoring techniques are essential. Traditional methods of detecting and monitoring deer such as scat surveys, spotlighting, or piloted aerial surveys can be expensive and time consuming. To overcome these issues, camera traps and remotely piloted aircraft systems (RPAS or drones) are increasingly being used to detect and monitor deer populations. This thesis presents a new method for assessing the imagery provided by RPAS and camera traps using Machine Learning, reducing the time and cost of assessing deer populations, providing the opportunity for more efficient management.
4
Goeders, James E. "Resolved sideband spectroscopy for the detection of weak optical transitions." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/49082.
Abstract:
This thesis reports on the setup of a new ion trap apparatus designed for experiments with single ⁴⁰Ca⁺ ions to perform molecular spectroscopy. The calcium ion is laser cooled, allowing for sympathetic cooling of the nonfluorescing molecular ion. The aim of these experiments is to explore loading and identifying molecular ions in RF-Paul traps, as well as developing new spectroscopic tools to measure transitions of molecular ions via the fluorescence of co-trapped ⁴⁰Ca⁺ ions. Ground state cooling of a mixed ion pair is implemented as a first step towards increasing the sensitivity of our technique to the level necessary to measure transitions with low scattering rates (like those present in molecular ions). Doppler cooling on the S(1/2)->P(1/2) transition of the calcium ion results in the formation of a Coulomb crystal, the behavior of which may be used to infer properties of the molecular ion. Following cooling, sideband spectroscopy on the narrow S(1/2)->D(5/2) quadrupole transition of calcium may be used to identify the mass of single molecular ions. This method is verified via a non-destructive measurement on ⁴⁰CaH⁺ and ⁴⁰Ca¹⁶O⁺. The normal modes of the Coulomb crystal can also be used to extract information from the target ion to the control ion. By driving the blue side of a transition, laser induced heating can be put into the two ion system, which leads to changes in fluorescence of the ⁴⁰Ca⁺ ion, first demonstrated with two Ca⁺ isotopes. Increasing the sensitivity of this technique requires ground state cooling of both the ⁴⁰Ca⁺ ion and the ion of interest, enabling the transfer of the ion's motional state into the ground state with high probability. This thesis demonstrates ground state cooling of the atomic ion and sympathetic cooling of a second ion (⁴⁴Ca⁺). Once in the ground state, heating of the Coulomb crystal by scattering photons off of the spectroscopy ion can be measured by monitoring the resolved motional sidebands of the S(1/2)->D(5/2) transition of ⁴⁰Ca⁺, allowing for spectral lines to be inferred. Future experiments will investigate this technique with molecular ions.
5
Kracke, Holger [Verfasser]. "Detection of individual spin transitions of a single proton confined in a cryogenic Penning trap / Holger Kracke." Mainz : Universitätsbibliothek Mainz, 2013. http://d-nb.info/1032368268/34.
6
Arnesson, Pontus, and Johan Forslund. "Edge Machine Learning for Wildlife Conservation : Detection of Poachers Using Camera Traps." Thesis, Linköpings universitet, Reglerteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-177483.
Abstract:
This thesis presents how deep learning can be utilized for detecting humans ina wildlife setting using image classification. Two different solutions have beenimplemented where both of them use a camera-equipped microprocessor to cap-ture the images. In one of the solutions, the deep learning model is run on themicroprocessor itself, which requires the size of the model to be as small as pos-sible. The other solution sends images from the microprocessor to a more pow-erful computer where a larger object detection model is run. Both solutions areevaluated using standard image classification metrics and compared against eachother. To adapt the models to the wildlife environment,transfer learningis usedwith training data from a similar setting that has been manually collected andannotated. The thesis describes a complete system’s implementation and results,including data transfer, parallel computing, and hardware setup. One of the contributions of this thesis is an algorithm that improves the classifi-cation performance on images where a human is far away from the camera. Thealgorithm detects motion in the images and extracts only the area where thereis movement. This is specifically important on the microprocessor, where theclassification model is too simple to handle those cases. By only applying theclassification model to this area, the task is more simple, resulting in better per-formance. In conclusion, when integrating this algorithm, a model running onthe microprocessor gives sufficient results to run as a camera trap for humans.However, test results show that this implementation is still quite underperform-ing compared to a model that is run on a more powerful computer.
7
Cummings, Elizabeth Ann. "Optical Detection of Ultracold Neutral Calcium Plasmas." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd692.pdf.
8
Heck, Michael [Verfasser], and Klaus [Akademischer Betreuer] Blaum. "Investigation of various excitation and detection schemes of stored ions in a Penning trap / Michael Heck ; Betreuer: Klaus Blaum." Heidelberg : Universitätsbibliothek Heidelberg, 2013. http://d-nb.info/1177148544/34.
9
Chalkha, Achouak. "Glow discharge electron impact ionisation and improvements of linear ion trap operating mode for in-the-field detection of illegal substances." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4704/document.
10
Anđelković, Zoran [Verfasser]. "Setup of a Penning trap for precision laser spectroscopy at HITRAP : trapping, cooling and electronic detection of externally produced ions / Zoran Andelkovic." Mainz : Universitätsbibliothek Mainz, 2012. http://d-nb.info/1023187825/34.
11
Fields, Robert Eugene 1958. "Application of a quadrupole ion trap mass spectrometer to ICP-MS and the direct detection of x-rays using a charge-injection device." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282314.
Abstract:
This work describes the construction of an inductively-coupled plasma tandem quadrupole mass spectrometer where a quadrupole ion storage trap acts as a second sector and collision cell to achieve neutralization or collisional dissociation of interfering species before mass analysis. Because most elements exist as singly-charged ions in an inductively-coupled plasma (ICP) plume, the ICP can be used as an ionization source for mass analysis (ICP/MS). By reducing the sample to elemental ions before mass analysis, ICP/MS spectra tend to be simple compared with those obtained by ICP-optical emission spectrometry (ICP-OES) where elements may have hundreds to thousands of emission lines and spectral overlaps can be severe. This is especially troublesome in the analysis of rare earth elements which have the largest numbers of active emission lines when excited in an ICP. In addition, detection limits by ICP/MS are often up to 3 orders of magnitude lower than by ICP-OES. ICP/MS analysis is not immune from isobaric and isotopic interferences or matrix effects. For most analyses, an acid digestion precedes aspiration as an aqueous solution into an argon plasma gas. This can lead to large amounts of Ar+ etc., which may interfere to varying degrees with analytes of interest. Oxides, argides and hydrides of matrix ions or other analytes may also form and interfere. These same processes can also split peak areas between the atomic form of an analyte and the molecular. In isotope ratio studies where precise measurements on more than one isotope per analyte are needed, these effects may be compounded. Isobaric interferences normally require high resolution mass analysis to resolve if they cannot be separated prior to sample introduction. However, the interface between a high vacuum, high resolution sector or ion cyclotron resonance mass spectrometer and an atmospheric pressure plasma is non-trivial and such instruments are expensive. The focus of this work is new approach which uses a collision cell where weakly-bound molecular species can be dissociated and ions with relatively high electron affinities, such as Ar+, can be neutralized through charge exchange reactions.
12
Xie, Xiaofeng. "High Flow Air Sampler for Rapid Analysis of Volatile and Semi-Volatile Organic Compounds." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/6165.
Abstract:
Volatile and semi-volatile organic compounds are ubiquitous, and some of them are hazardous. The ability to rapidly detect and identify trace levels of them in air has become increasingly important. The conventional device used today for sampling and concentrating them in air is thermal desorption tubes filled with specific sorbents, which can only collect air samples at flow rates of 100-200 mL/min. In order to detect low concentration (ppt level) VOC compounds, long sampling time (>2 h) and sensitive detection are required. At the same time, portable instrumentation for on-site analysis has been developing rapidly. The somewhat lower performance of portable instruments compared to benchtop systems requires the sampling of even greater sample volume in order to reach the same detection limits. In this study, two high flow rate air sampling devices, i.e., a multi-capillary trap and a concentric packed trap, were developed to sample a large volume of air in a short time period. The multi-capillary trap was constructed by bundling analytical capillary gas chromatography columns together in parallel. As low as single digit ppt detection limits were reached in less than 25 min with this trap, and as high as 8.0 L/min flow rate was sampled. The simple and compact multi-capillary trap could be easily used with a conventional thermal desorption system to perform high flow rate sampling. A concentric packed high flow rate trap was also developed by packing sorbent layers concentrically around an empty tube. The concentric packed trap achieved a high flow rate (>10 L/min) because it had a high surface area and short sorbent bed. Also, its large sorbent amount (>1 g) provided large breakthrough volume (>100 L) required to achieve low detection limits. An equilibrium distribution sampling system was developed by absorbing selected analytes in granular PDMS to provide calibration for on-site instrumentation. Furthermore, a needle trap device was coupled in tandem to both high flow rate air samplers to perform second-stage concentration of VOCs down to the ppt level. Concentration factors of 104 to 105 were achieved within 30 min using both systems, i.e., over 10 to 100 times more sample was collected compared to conventional TD systems.
13
Roux, Christian-Eric [Verfasser], and Klaus [Akademischer Betreuer] Blaum. "High-resolution mass spectrometry: The trap design and detection system of Pentatrap and new Q-values for neutrino studies / Christian-Eric Roux ; Betreuer: Klaus Blaum." Heidelberg : Universitätsbibliothek Heidelberg, 2012. http://d-nb.info/1177039915/34.
14
Ebrahimi, Mohammad Sadegh [Verfasser], and Wolfgang [Akademischer Betreuer] Quint. "Non-Destructive Detection and Resistive Cooling of Highly-Charged-Ion Ensembles for Precision Spectroscopy in the ARTEMIS Penning Trap / Mohammad Sadegh Ebrahimi ; Betreuer: Wolfgang Quint." Heidelberg : Universitätsbibliothek Heidelberg, 2018. http://d-nb.info/1177251744/34.
15
Kim, Hang Joon. "The Generalized Multiset Sampler: Theory and Its Application." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1338332071.
16
Krasselt, Cornelius, Jörg Schuster, and Borczyskowski Christian von. "Photoinduced hole trapping in single semiconductor quantum dots at specific sites at silicon oxide interfaces." Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-122745.
Abstract:
Blinking dynamics of CdSe/ZnS semiconductor quantum dots (QD) are characterized by (truncated) power law distributions exhibiting a wide dynamic range in probability densities and time scales both for off- and on-times. QDs were immobilized on silicon oxide surfaces with varying grades of hydroxylation and silanol group densities, respectively. While the off-time distributions remain unaffected by changing the surface properties of the silicon oxide, a deviation from the power law dependence is observed in the case of on-times. This deviation can be described by a superimposed single exponential function and depends critically on the local silanol group density. Furthermore, QDs in close proximity to silanol groups exhibit both high average photoluminescence intensities and large on-time fractions. The effect is attributed to an interaction between the QDs and the silanol groups which creates new or deepens already existing hole trap states within the ZnS shell. This interpretation is consistent with the trapping model introduced by Verberk et al. (R. Verberk, A. M. van Oijen and M. Orrit, Phys. Rev. B, 2002, 66, 233202).
17
Paolino, Roberta Montanheiro. "Importância das Áreas de Preservação Permanente (APP) ripárias para a mastofauna no nordeste do Estado de São Paulo." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/59/59139/tde-19102015-122518/.
Abstract:
Dada a crescente ameaça à biodiversidade pela destruição e fragmentação dos habitats naturais, sobre-exploração, poluição e introdução de espécies exóticas invasoras, alguns veículos legais buscam preservá-la, como a instituição das Áreas de Preservação Permanente (APP) no Brasil. Elas têm sido alvo de grande discussão quanto à sua configuração com a aprovação da Lei Nº 12.651/2012, a qual alterou o Código Florestal Brasileiro. Assim, este trabalho visa avaliar se as APPs estão sendo capazes de manter a diversidade de mamíferos de médio e grande porte em uma região de agricultura e silvicultura intensivas no nordeste do estado de São Paulo. Além da perspectiva da comunidade, a importância das APPs foi também avaliada através da análise de sua influência na abundância média relativa de Leopardus pardalis (jaguatirica). Foram instaladas armadilhas fotográficas digitais em três paisagens: a primeira compreendendo a Estação Ecológica de Jataí, a Estação Experimental de Luiz Antônio e seu entorno, em Luiz Antônio; a segunda na Fazenda Cara Preta, que possui APP e Reservas Legais (RL) da International Paper (IP), e seu entorno, em São Simão; e a terceira abrangendo a Floresta Estadual de Cajuru, a Fazenda Dois Córregos, com APP e RLs da IP, e seu entorno, em Cajuru e Altinópolis. Foram amostrados 208 pontos aleatoriamente, 169 fora e 39 dentro de APP. As câmeras funcionaram durante 30 dias em cada ponto, 24 horas por dia, de abril a setembro de 2013 na primeira paisagem e de 2014 nas segunda e terceira. A comparação entre a diversidade dentro e fora de APP foi feita através da riqueza observada por curvas de rarefação e do Wildlife Picture Index (WPI), índice de biodiversidade que considera variações na detecção por ser uma média geométrica dos valores de ocupação das espécies observadas. As probabilidades de detecção e ocupação foram estimadas através do modelo de ocupação multiespécies por análise bayesiana, nos programas R 3.1.1 e JAGS 3.4 pelo pacote jagsUI. Na modelagem, foram utilizadas as covariáveis de distância mínima de estrada de terra, chuva, temperatura (linear e quadrática) para detecção, e de quantidade de floresta nativa, silvicultura e cana-de-açúcar em um buffer de 200 ha de cada ponto para ocupação. Os valores de ocupação foram utilizados para calcular o WPI para pontos dentro e fora de APP e para APP de Unidades de Conservação (UC), consideradas detentoras da diversidade esperada para a região. Já a abundância média relativa da jaguatirica (lambda) foi estimada por modelos de Royle & Nichols com as covariáveis distância mínima de estrada de terra, chuva e temperatura para detecção, e APP, grau de proteção e quantidade de floresta nativa, silvicultura e cana-de-açúcar em um buffer de 200 ha de cada ponto para o lambda. Nos dois anos de amostragem, foram registradas 34 espécies de mamíferos, 28 nativas e seis exóticas, nas três paisagens. As curvas de rarefação não apresentaram diferença estatística entre pontos dentro e fora de APP, dentro e fora de UC. Porém, foi necessário mais do que o quádruplo do esforço amostral para que fosse registrada em pontos fora de APP fora de UC uma riqueza semelhante à encontrada nas APPs fora de UC, o que pode ser resultado das populações terem menor densidade na matriz e estarem concentradas nas APPs, indicando a função das mesmas como corredores. A distribuição de valores de WPI para pontos em APP também não apresentou diferença em relação aos pontos fora de APP. Além disso, as APPs de UC apresentaram maior diversidade do que as APPs fora de UC, indicando que as APPs não estão sendo capazes de manter a diversidade de mamíferos de médio e grande porte esperada para a região. Isso pode estar ocorrendo em função da configuração das APPs, as quais são estreitas, tendo, em sua maioria, 30 m. Dessa forma, elas possuem menor heterogeneidade de micro-habitats e são fortemente afetadas pelo efeito de borda, favorecendo espécies generalistas e não permitindo ambiente propício às espécies florestais. Estudos mostram que corredores devem ter no mínimo de 140 a 400 m para apresentarem a mesma comunidade de áreas contínuas. Além disso, a paisagem influencia na função das APPs, pois, nas áreas de estudo, o entorno dos pontos fora de APP possui quase a mesma quantidade de vegetação nativa do que o entorno dos pontos em APP, o que também pode justificar a ausência de diferença entre eles, dado que a floresta nativa teve efeito positivo na ocupação. Por outro lado, as APPs apresentaram efeito positivo na abundância média relativa da jaguatirica e mostraram-se fundamentais para a conservação dessa espécie, principalmente por sua função como habitat e corredores, dado que a jaguatirica mostrou-se extremamente dependente da quantidade de floresta nativa, covariável que melhor explicou a abundância média relativa. Assim, as APPs são importantes para a conservação da mastofauna, a exemplo de sua influência na população da jaguatirica. Contudo, é preciso revisar a configuração atual das APPs na legislação para que elas cumpram totalmente sua função de preservar a biodiversidade.The habitat loss and fragmentation, the overexploitation, the pollution and the introduction of alien species have threatened the biodiversity and increased extinction rates. Therefore, some legal resolutions aim to preserve it such as the Permanente Preservation Areas (PPA) in Brazil, which have been the focus of a great discussion regarding its configuration after the approval of the law Nº 12.651/2012 that changed the Brazilian Forest Code. Thus, the purpose of this study is to analyse if the PPA are maintaining the diversity of medium and large sized mammals in a region of intensive agriculture and sylviculture in the northeast of the state of São Paulo. Additionally to the community approach, the importance of PPA was assessed through the analysis of its effect on the relative mean abundance of Leopardus pardalis (ocelot). We used camera-traps in three study areas: Jataí Ecological Station, Luiz Antônio Experimental Station and its buffer, in the municipality of Luiz Antônio; the Cara Preta Farm, which has PPA and Legal Reserves (LR) of the International Paper company (IP), and its buffer in São Simão; and the State Forest of Cajuru and the Dois Córregos Farm, which has PPA and LR of the IP, and its buffer, in Cajuru and Altinópolis. A total of 208 points was sampled randomly, 169 outside and 39 inside PPA. Cameras worked during 30 days at each point, 24 hours a day, from April to September in 2013 at the first area and in 2014 at the second and third areas. We used rarefaction curves of observed richness and the Wildlife Picture Index (WPI) to compare the diversity inside and outside PPA. The WPI deals with imperfection detection because it is a geometric mean of the occupancy of observed species. We estimated the detection and occupancy probabilities by the multi-species occupancy model with bayesian analysis in R 3.1.1 and JAGS 3.4 with package jagsUI. We analysed the effect of the site covariates minimum distance of unpaved road, rain and temperature (linear and quadratic) on detection, and of quantities of native forest, sylviculture and sugarcane in a buffer of 200 ha of the sample points on occupancy. The values of occupancy were used to compute the WPI for points inside and outside PPA inside and outside protected areas (PA), which have the diversity expected in the region. Moreover, we estimated the relative mean abundance (lambda) of ocelot by Royle & Nichols models with the effect of site covariates: minimum distance of unpaved road, rain and temperature on detection, and of PPA, degree of protection and quantities of native forest, sylviculture and sugarcane in a buffer of 200 ha of the sample points on lambda. We recorded 34 species of mammals, 28 natives and six alien, in the three landscapes. The rarefaction curves did not showed statistic difference between the points inside and outside PPA, inside and outside PA. However, it was necessary four times the sample effort to record the same richness of points inside PPA outside PA in points outside PPA outside PA. It may have happened due to a low density of the populations in the matrix and a high density inside PPA, suggesting the role of PPA as corridors. The WPI distribution also did not show difference between the points inside and outside PPA. In addition, the PPA of PA had a high diversity when compared with PPA outside PA, suggesting that PPA are not maintaining the diversity of medium and large sized mammals expected in the region. This may be a result of PPAs configuration, because they are narrow, as most are just 30 m wide. Hence, they have less heterogeneity of micro-habitats and are highly affected by edge effect, what benefit generalist species over forest ones. Studies show that corridors must have a minimum of 140 to 400 m to possess the same community of continuous areas. Further, the landscape influences the role of PPA, because the surroundings of points outside PPA have almost the same quantity of native vegetation than the surroundings of points inside PPA in the study areas, what may also explain the lack of difference between them because native forest presented a positive effect on occupancy. On the other hand, PPA had a positive effect on the relative mean abundance of ocelot and were fundamental to the conservation of this species due to its role as habitat and corridors. The quantity of native forest was the covariate that best explained lambda, indicating that ocelots are dependent of dense vegetation. Overall, PPA were considered important to the conservation of mammals given its positive effect on ocelot population. Nevertheless, it is advisable to revise the current configuration of PPA, as is stated in the law, for these areas to really fulfill their role in biodiversity conservation.
18
Wang, Junting. "Miniaturized Electrostatic Ion Beam Trap Mass Analyzer." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3610.
Abstract:
The electrostatic ion beam trap (EIBT) was designed by D. Zajfman during the previous decade. This ion trap combines many properties of the Fourier-transform ion cyclotron resonance (FTICR) mass analyzer and time-of-flight (TOF) mass analyzer. There are several advantages for the electrostatic ion beam trap. First, large mass-to-charge particles in an electrostatic field could be easier to analyze. Second, there is a folded flight path, which could make the mass analyzer smaller compared to conventional TOF mass analyzer. This principle of operation of this ion trap is analogous to an optical resonator. The ions are trapped in a voltage valley and oscillate between the two parallel sets of mirror electrodes with high voltages. In this thesis, I first describe a new type of miniaturized electrostatic ion beam trap mass analyzer that consists of two printed circuit boards (PCBs). The facing surfaces of these boards are imprinted with copper electrodes. The center of the boards is field free and at ground potential with ion mirrors and Einzel lenses on either side. A charge detector is attached to the center for recording the time-dependant motion of the ions in the field. The PCB-based EIBT design is easier to construct than the original EIBT mass analyzer. The electrostatic fields are optimized by adjusting the potential on the mirror electrodes as well as the geometry of the electrodes. Although nondestructive charge detection is much less sensitive for small ions, this detection is ideal for analysis of large ions. The planar electrostatic ion beam trap is inexpensive, small, and simple to operate. The PCB EIBT device was designed, built, and tested using metal samples such as copper and nickel. The electric field of the PCB EIBT is not the same as that of the original EIBT. Unfortunately, there were no ion signals captured in image charge detector. Another new type of miniaturized electrostatic ion beam trap was made by depositing electrodes onto Kapton film. Seven thin tin/copper traces (1 mm wide by 0.015 mm thick) were deposited onto each side of a flat, flexible circuit board substrate (Kapton film 0.15 mm thickness). The film was rolled to form a cylinder. The flexible EIBT is small (4.5 cm × 8 cm), and lightweight (~1 g). This device was tested using laser ablation of CsI. The CsI signals were detected by the charge detector, amplified and sent to the oscilloscope. Fourier transformation was used to convert the data to the frequency domain spectrum. The resolution of Cs+ is around 1000 (m/Δm) from initial flexible EIBT test. The mass accuracy of the Cs+ peak is better than 0.1%.
19
Melconian, Dan G. "A positron detector for precision beta decay experiments from a magneto-optic trap." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ61469.pdf.
20
Shen, Li. "Innovative Procedures for Travel Data Collection and Processing." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/14188.
Abstract:
Global Positioning System (GPS) or Smartphone technology has been increasingly used in travel data collection. Although GPS devices can directly record spatial and temporal information, trip ends, travel modes and trip purposes are not recorded. So GPS data processing becomes a critical procedure to produce these results, which can be used in transport planning. It has been proved that GPS records are more reliable than travel diaries; however, the quality of GPS data processing work usually influences the quality of results. Researchers have been engaging in the improvement of GPS data processing for the past decade. Traditionally, data processing for GPS records (from dedicated GPS loggers and Smartphones) includes three steps, namely trip identification, mode detection and purpose imputation. However, the results of mode and purpose detection are entirely based on the result of trip identification. Hence, the total accuracy of a GPS survey would be the product of the accuracy of each step. This thesis focuses on the improvement of travel data quality by improving data collection and processing. In this study, a new procedure is introduced which combines the process of trip identification and mode detection. Some general rules (i.e., a threshold of dwell time and the time interval for recording data) are tested. This research also firstly applies a new technology, a life-logging camera, to travel data collection. Images are used to help to pursue ground truth -- especially recorded trips in which GPS data were missing -- and detect some types of travel modes in order to improve the accuracy of data processing. An automating image processing procedure is proposed and tested in this study. In addition, a concept of “mode-point-chain” is discussed to identify the cases of mode change and modify incorrect mode detection results. For the process of purpose imputation, more travel information is suggested to be used in the process. This thesis also uses tour-based information in trip purpose imputation to improve the results. By using the new procedure, the trip identification accuracy was increased by almost 30 percent, taking the missing trips into account. Since trip identification and mode detection were combined, this increase also benefits mode detection results. With the help of image processing and the new procedure of mode change detection, the accuracy of mode detection increased by 7% regardless of the accuracy increase in trip identification. The new processing method also increased the accuracy of trip purpose imputation by 8%. This improvement can help researchers and planners obtain more accurate data for decision making and planning.
21
氷, 韓., and Hyo Kan. "Studies on the application of two‐phase separation mixed solution to separation and detection technology." Thesis, https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13127442/?lang=0, 2020. https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13127442/?lang=0.
Abstract:
The following were examined by taking advantage of TRDP using two-phase separation mixed solution: protein separation by the TRDC with the ternary mixed solution of water–acetonitrile–ethyl acetate, optical isomers separation by the TRDC with the ternary solution containing cyclodextrin as a chiral recognition molecule, development of the TRDC with a water–acetonitrile mixed solution containing sodium chloride as a two-phase separation mixed solution instead of the ternary solution, and introduction of the principle of the TRDC to a commercial HPLC system. Furthermore, the peroxioxalate CL detection was for the first time examined by using the ternary mixed solution. The investigation of the TRDP and TRDC, as well as the ternary mixed solution of water–acetonitrile–ethyl acetate, are interesting in view of not only analytical chemistry but also chemical engineering, and physical chemistry.博士(工学)
Doctor of Philosophy in Engineering
同志社大学
Doshisha University
22
Vadlejch, Daniel. "Charakterizace mikropohybu a jeho vliv na systematické posuvy frekvence kvadrupólového přechodu iontu vápníku zachyceného v Paulově pasti." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417151.
Abstract:
This thesis deals with the analysis of micromotion of a single charged calcium ion trapped inside the linear Paul's ion trap and the influence of residual micromotion on the systematic frequency shifts of the clock transition of calcium ion. The fundamental properties of the motion of an ion confined within linear Paul's ion trap are shown in general using a theoretical description. The micromotion component of the overall motion is especially emphasized. A model expressing micromotion in the axial direction of the trap is introduced on the basis of the results of the numerical calculation of electric fields inside the trap. The model is compared to the reality experimentally. Then, the photon-correlation method of detection of micromotion is introduced and subsequently used to minimize and to estimate a measure of residual micromotion in all spacial directions. According to the achievable measure of residual micromotion, the systematic frequency shifts caused by this micromotion are estimated. It can be seen that we are able to reach uncertainties of the relative frequency shifts due to micromotion below 10^20. We expect that uncertainty of total motional systematic frequency shift is in our case limited by thermal motion.
23
Linke, Norbert Matthias. "Background-free detection and mixed-species crystals in micro- and macroscopic ion-traps for scalable QIP." Thesis, University of Oxford, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.669935.
Abstract:
Scalability and the implementation of fault tolerant quantum gates are the two main challenges which must be overcome in order to unlock the vast potential of quantum computing. This thesis describes work with calcium ions trapped in both microscopic and macroscopic linear Paul traps addressing both of these issues. We describe the assembly of a microstructured multi-zone ion trap which forms part of our group's contribution to the European "Microtrap" collaboration. We report the successful trapping of ions and characterization of the trap as well as a measurement of the heating rate. In miniaturized trap structures such as this one, background scattered light from the cooling beam causes difficulties. We introduce and demonstrate experimentally two techniques to overcome this problem. The first achieves background-free detection of ions using different repumping methods to enable the filtering out of the excitation wavelength. The second makes possible background-free readout of trapped ion qubits by separating in time the excitation and detection steps The second half of the thesis describes our experimental efforts towards implementing a two-qubit entangling gate with a mixed-species crystal. We describe the setup and characterization of a new macroscopic trap including the trapping and coherent manipulation of the internal states of both 40Ca+ and 43Ca+ ions. We accomplish the simultaneous independent readout of two qubits implemented in a 40Ca+ - 43Ca+ ion pair. We also present the setup and characterization of two injection-locked frequency-doubled Raman lasers and demonstrate coherent manipulation as well as a measurement of the off-resonant photon scattering error they introduce. Finally, we use them to achieve sideband cooling to the motional ground state of a mixed species ion crystal.
24
Bassaler, Julien. "Propriétés de transport électronique et performances de HEMT à canal AlGaN pour l'électronique de puissance." Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALY002.
Abstract:
La demande croissante en énergie exige la création d'infrastructures nouvelles et adaptées, et le développement de l'électronique de puissance joue un rôle clé dans cette quête. L'utilisation de semi-conducteurs à large bande interdite, en raison de leurs propriétés physiques supérieures au silicium, s'avère être la voie la plus prometteuse pour concevoir des composants plus performants. Bien que les transistors à haute mobilité électronique (HEMT) à base de GaN sur silicium soient déjà commercialisés, leur tension de fonctionnement est limitée à 650 V et ils montrent une nette dégradation de leurs performances à des températures élevées. Les HEMT à canal AlGaN sur silicium offrent la possibilité de repousser ces limites tout en proposant des coûts de fabrication moindres par rapport aux composants SiC.Dans un premier temps, une hétérostructure AlGaN/GaN/AlN avec un canal très mince a été étudiée. L'objectif est d'accroître le champ de claquage de la structure en minimisant l'impact du canal GaN sur celle-ci. L’analyse des propriétés de transport dans cette hétérostructure par effet Hall a révélé une mobilité électronique relativement faible, associée à une anisotropie en fonction de l'orientation cristalline. Cette constatation a été appuyée par une analyse structurelle de l’empilement de couches, ainsi que par la détection de défauts électriquement actifs, renforçant ainsi les conclusions obtenues par effet Hall. De plus, les modèles de diffusion des porteurs de charge ont montré que la rugosité d’interface constituait le principal mécanisme limitant la mobilité électronique.Par la suite, une analyse détaillée des hétérostructures à canal AlGaN sur silicium a été effectuée. Une étude des défauts par spectroscopie de transitoire de niveaux profonds (DLTS) dans la couche d'AlN épitaxiée sur le substrat Si (111) a été réalisée pour évaluer la qualité de cette couche qui influence la qualité globale de l’hétérostructure. Sur la base de modèles physiques, une étude des propriétés de transport dans ces hétérostructures à canal AlGaN a ensuite permis de déterminer les compositions optimales en Al pour les couches d'AlGaN. L'impact de la fraction d'aluminium dans le canal AlGaN sur la mobilité électronique a été étudié expérimentalement par des mesures d’effet Hall. Ces résultats expérimentaux ont été comparés aux modèles de diffusion des porteurs de charge et à des simulations pour identifier les facteurs limitants de la mobilité. Bien que le désordre d'alliage soit le principal mécanisme limitant dans ces structures, son impact est moins prononcé que ce qui est attendu. Les observations indiquent également une dégradation des propriétés de transport moins sévère par rapport aux hétérostructures à canal GaN, démontrant ainsi une stabilité thermique supérieure.Enfin, la dégradation des performances des transistors en fonction de la température a été évaluée selon la fraction d'Al du canal AlGaN ainsi qu’en fonction du substrat (Si et AlN) et de la structure de grille. Si l'augmentation de la fraction d'Al dans le canal induit une réduction du courant à l'état passant, cela permet aussi de réduire le courant à l’état bloquant et d’obtenir une meilleure stabilité en température des performances. Les mécanismes responsables des courants de fuite de grille ont été identifiés en comparant les modèles aux résultats expérimentaux. Il apparait que l’augmentation de la fraction d’Al permet en effet de réduire l’intensité de ces mécanismes.En conclusion, les HEMT à canal AlGaN présentent une stabilité thermique des performances à l’état passant supérieure ainsi qu’une amélioration significative de l’état bloquant. Ces composants possèdent donc un excellent potentiel pour les applications à haute tension et haute températureThe increasing demand for energy requires the development of new and suitable infrastructure, and the advancement of power electronics plays a pivotal role in addressing this need. Utilizing wide-bandgap semiconductors, due to their superior physical properties compared to silicon, emerges as the most promising avenue for designing high-performance components. While high electron mobility transistors (HEMT) based on GaN on silicon are already commercialized, their operating voltage is limited to 650 V, and they exhibit substantial performance degradation at elevated temperatures. HEMTs with AlGaN channels on silicon offer the potential to overcome these limitations while also offering lower production costs compared to SiC devices.Initially, an AlGaN/GaN/AlN heterostructure with an ultrathin channel was investigated. The objective was to enhance the breakdown voltage of the structure by minimizing the impact of the GaN channel. An analysis of the transport properties in this heterostructure using Hall effect measurements revealed relatively low electron mobility, coupled with anisotropy depending on the crystal orientation. This finding was substantiated by a structural analysis of the layer stack and the detection of electrically active defects, further supporting the conclusions drawn from the Hall effect measurements. Furthermore, charge carrier diffusion models indicated that interface roughness constituted the primary limiting mechanism for electron mobility.Subsequently, a detailed analysis of AlGaN channel heterostructures on silicon was conducted. Deep-level transient spectroscopy (DLTS) was used to study defects in the AlN layer epitaxially grown on the Si (111) substrate, which influences the overall quality of the heterostructure. Based on physical models, a study of the transport properties in these AlGaN channel heterostructures was then performed to determine the optimal Al compositions in the AlGaN layers. The impact of the aluminum fraction in the AlGaN channel on electronic mobility has been studied experimentally by Hall effect measurements. These experimental results were compared to charge carrier diffusion models and simulations to identify mobility-limiting factors. While alloy disorder was identified as the primary limiting mechanism in these structures, its impact was less pronounced than expected. Observations also indicated a less severe degradation of transport properties compared to GaN channel heterostructures, demonstrating superior thermal stability.Finally, the degradation of transistor performance with temperature was assessed based on the aluminum fraction in the AlGaN channel, substrate choice (Si and AlN), and gate structure. Increasing the aluminum fraction in the channel not only led to a reduction in on-state current but also reduced off-state leakage current, resulting in improved thermal stability of performance. The mechanisms responsible for gate leakage currents were identified by comparing models with experimental results, revealing that increasing the aluminum fraction effectively reduces the intensity of these mechanisms.In conclusion, AlGaN channel HEMTs exhibit superior thermal stability of on-state performance and a significant enhancement of off-state blocking characteristics. These devices thus hold excellent potential for high-voltage and high-temperature applications
25
Dong, Jingyuan. "Power System Disturbance Analysis and Detection Based on Wide-Area Measurements." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/30129.
Abstract:
Wide-area measurement systems (WAMS) enable the monitoring of overall bulk power systems and provide critical information for understanding and responding to power system disturbances and cascading failures. The North American Frequency Monitoring Network (FNET) takes GPS-synchronized wide-area measurements in a low-cost, easily deployable manner at the 120 V distribution level, which presents more opportunities to study power system dynamics. This work explores the topics of power system disturbance analysis and detection by utilizing the wide-area measurements obtained in the distribution networks.
In this work, statistical analysis is conducted based on the major disturbances in the North American Interconnections detected by the FNET situation awareness system between 2006 and 2008. Typical frequency patterns of the generation and load loss events are analyzed for the three North American power Interconnections: the Eastern Interconnection (EI), the Western Electricity Coordinating Council (WECC), and the Electric Reliability Council of Texas (ERCOT). The linear relationship between frequency deviation and frequency change rate during generation/loss mismatch events is verified by the measurements in the three Interconnections. The relationship between the generation/load mismatch and system frequency is also examined based on confirmed generation loss events in the EI system. And a power mismatch estimator is developed to improve the current disturbance detection program. Various types of power system disturbances are examined based on frequency, voltage and phase angle to obtain the event signatures in the measurements.
To better understand the propagation of disturbances in the power system, an automated visualization tool is developed that can generate frequency and angle replays of disturbances, as well as image snapshots. This visualization tool correlates the wide-area measurements with geographical information by displaying the measurements over a geographical map. This work makes an attempt to investigate the visualization of the angle profile in the wide-area power system to improve situation awareness.
This work explores the viability of relying primarily on distribution-level measurements to detect and identify line outages, a topic not yet addressed in previous works. Line outage sensitivity at different voltage levels in the Tennessee Valley Authority (TVA) system is examined to analyze the visibility of disturbances from the point of view of wide-area measurements. The sensor placement strategy is proposed for better observability of the line trip disturbances. The characteristics of line outages are studied extensively with simulations and real measurements. Line trip detection algorithms are proposed that employs the information in frequency and phase angle measurements. In spite of the limited FDR coverage and confirmed training cases, an identification algorithm is developed which uses the information in the real measurements as well as the simulation cases to determine the tripped line.Ph. D.
26
Sanguinetti, Stefano. "ATOMIC PARITY VIOLATION IN HEAVY ALKALIS: Detection by Stimulated Emission for Cesium and Traps for Cold Francium." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2004. http://tel.archives-ouvertes.fr/tel-00006785.
Abstract:
Le travail présenté porte sur les progrès récents d'expériences de spectroscopie atomique sur césium et francium, visant à des mesures précises de violation de parité (PV) dans ces atomes. Dans le cadre d'une “thèse en cotutelle”, le candidat s'est consacré d'une part aux mesures PV préliminaires (8% de précision) de l'actuelle expérience Cs au LKB à Paris, et d'autre part à la préparation d'un échantillon d'atomes radioactifs de Fr (production et piégeage) aux LNL (INFN) en Italie. Ces deux expériences sont à des stades très différents. Les mesures présentées pour le Cs s'inscrivent en fait dans la lignée d'un travail commencé en 1991, pour la détection de PV par émission stimulée. L'expérience italienne est par contre à ses débuts: pour pouvoir sonder les propriétés du Fr, instable, il faut d'abord produire et rassembler un nombre suffisant d'atomes. La conception de montages PV qui ont démontré leur validité sur le césium constitue une solide base de départ pour le cas du francium.
27
Tran, Dang-Hoan Verfasser], Kai-Uwe [Akademischer Betreuer] [Sattler, Mohamed Medhat [Gutachter] Gaber, and Peter [Gutachter] Fischer. "Change Detection in Streaming Data / Dang-Hoan Tran ; Gutachter: Mohamed Medhat Gaber, Peter Fischer ; Betreuer: Kai-Uwe Sattler." Ilmenau : TU Ilmenau, 2013. http://d-nb.info/1178183904/34.
28
Tran, Dang Hoan [Verfasser], Kai-Uwe [Akademischer Betreuer] Sattler, Mohamed Medhat [Gutachter] Gaber, and Peter [Gutachter] Fischer. "Change Detection in Streaming Data / Dang-Hoan Tran ; Gutachter: Mohamed Medhat Gaber, Peter Fischer ; Betreuer: Kai-Uwe Sattler." Ilmenau : TU Ilmenau, 2013. http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2013000513.
29
Bazkir, Ozcan. "Realization Of Detector Based Spectral Responsivity Scale From Ultraviolet To Near Infrared Regions Of Electromagnetic Spectrum." Phd thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605148/index.pdf.
Abstract:
Realization of spectral responsivity scale was studied in three stages. Firstly, absolute optical power measurements using Electrical Substitution Cryogenic Radiometer (ESCR) was studied. The absolute measurements were done at discrete laser wavelengths of tunable Ar+ (488 nm and 514.5 nm), Nd:YAG (532 nm) and fixed He-Ne (632.8 nm) laser sources. To increase measurement accuracy the method used for the stabilization of laser beams, transmittance measurements of optical windows, and minimization of scattered beams were discussed.
Secondly, realization of absolute responsivity scale between 350- 850 nm ranges was studied. The scale based on reflection type trap detectors consisting of three silicon photodiodes. Various measurement systems were established in order to make optical characterization of trap detectors like non-linearity, surface non-homogeneity, polarization dependency, reflectance, and internal quantum efficiency. The absolute responsivity was linked to the absolute optical power by measuring the current response of trap detectors to the absolute power measured by ESCR system at laser wavelengths. Using models for the trap detector&rsquos, reflectance and internal quantum efficiency the scale between 350- 850 nm ranges was realized with an uncertainty of 0.05 %. Finally, the spectral responsivity scale in ultraviolet (UV) and near-infrared (NIR) regions was realized using Electrically Calibrated Pyroelectric Radiometer (ECPR). Optically characterizing the spatial non-uniformity of pyroelectric detector and its surface reflectance, the spectral responsivity scale was established with uncertainties ±
0.5-1.0 % between 250 nm and 350 nm and ±
0.5-1.5 % between 850 and 2500 nm.
30
Pässler, Roland. "Alternative Way for Detecting Franck-Condon Shifts from Thermally Broadened Photoneutralization Cross-Section Bands of Deep Traps in Semiconductors." Universitätsbibliothek Chemnitz, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-201000270.
31
Ikram, M. "Radio-frequency generation of an electron plasma in a Malmberg-Penning trap and its interaction with a stationary or pulsed electron beam." Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/233616.
Abstract:
Experiments and numerical investigations on trapped electron plasmas and traveling electron bunches are discussed.
A Thomson backscattering diagnostics set up was installed in the ELTRAP (Electron TRAP) device, a Penning-Malmberg trap operating at the Department of Physics of the University of Milano since 2001. Here, an infrared (IR) laser pulse collides with nanosecond electron bunches with an energy of 1-20 keV traveling through a longitudinal magnetic field in a dynamical regime where space-charge effects play a significant role. The backscattered radiation is optically filtered and detected by means of a photomultiplier tube. The minimum sensitivity of the backscattering diagnostics has been estimated for the present set-up configuration. Constraints on the number of photons and thus on the information one can obtain with the Thomson backscattering technique are determined by the relatively low density of the electron beam as well as by noise issues. Solutions to increase the signal level and to reduce the noise are briefly discussed.
The generation of an electron plasma by stochastic heating was realized in ELTRAP under ultra-high vacuum conditions by means of the application of low power RF (1-20 MHz) drives on one of the azimuthally sectored electrodes of the trap. The relevant experimental results are reviewed. The electron heating mechanism has been studied by means of a two-dimensional (2D) particle-in-cell (PIC) code, starting with a very low electron density, and applying RF drives of various amplitudes in the range 1-15 MHz on different electrodes. The axial kinetic energy of the electrons is in general increasing for all considered cases. Of course, higher temperature increments are obtained by increasing the amplitude of the RF excitation. The simulation results indicate in particular that the heating is initially higher close to the cylindrical wall of the device. These results on the electron heating point in the same direction of the experimental findings, where the plasma formation due to the ionization of the residual gas is found to be localized close to the trap wall. The simulations indicate also major heating effects when the RF drive is applied close to one end of the trap. Similar results are obtained for an electron plasma at higher densities, simulating a situation in which the RF is applied to an already formed plasma.
With the aim to extend these RF studies to the microwave range, a bench test analysis has been performed of the transmission efficiency of a microwave injection system up to a few GHz. The test was based on the use of a prototype circular waveguide with the same diameter and length of the ELTRAP electrode stack and of a coupled rectangular waveguide with dimensions suitable for a future installation in the device.
Electromagnetic PIC simulations have also been performed of the electron heating effect, again both at very low and relatively high electron densities, applying a microwave drive with a frequency of approximately 3 GHz close to the center and close to one end of the trap.
Both the bench test of the injection system and the numerical simulations indicate that the new microwave heating system will allow the extension of the previous RF studies to the GHz range. In particular, the electron cyclotron resonance heating of the electrons will be aimed to increasing the electron temperature, and possibly its density as a consequence of a higher ionization rate of the residual gas. The installation of the new RF system will open up the possibility to study, e.g., the interaction between the confined plasma and traveling electron bunches.
32
Hata, Misako. "Comparison of a novel cell-based reporter assay and a competitive binding ELISA for the detection of thyrotropin-receptor (TSHR) autoantibodies (TRAb) in Graves' disease patients." Ohio : Ohio University, 2010. http://www.ohiolink.edu/etd/view.cgi?ohiou1262099140.
33
Hoendervanger, Lynn. "A New Metastable Helium Machine : An Investigation into the Attributes of Trapping, Cooling and Detecting Metastable Helium." Thesis, Palaiseau, Institut d'optique théorique et appliquée, 2014. http://www.theses.fr/2014IOTA0006/document.
Abstract:
Cette thèse décrit le travail accompli au cours des trois dernières années sur la nouvelle expérience d’Hélium métastable de l'Institut d'Optique à Palaiseau.Le premier chapitre décrit une étude visant à améliorer à la fois l'efficacité et la précision du système de détection par galettes à micro-canaux (MCP). Nous avons fait des mesures avec des galettes recouvertes d'une couche d'or sur la face avant, obtenant un accroissement de l'efficacité de détection mais également une réduction de la précision. L'ajout d'une tension intermédiaires entre les deux galettes empilées a au contraire améliorer à la fois l'efficacité et la précision des MCP, en l’absence d’une couche d’or.Le deuxième chapitre est consacré à la construction de l'appareil expérimental pour le refroidissement et le piégeage d’atomes. L’excitation de l'état fondamental de l’Hélium à l'état métastable est décrite, ainsi que la collimation et le refroidissement ultérieur par Zeeman lent du faisceau atomique chaud résultant. Le faisceau ralenti est alors capturé dans un piège magnéto-optique (PMO), dans lequel nous avons capturé 8x108 atomes.Dans le troisième chapitre une étude originale du refroidissement Doppler tridimensionnel dans un PMO et une mélasse désaccordée vers le rouge de la transition atomique est discutée. L’atome d’Hélium métastable est unique et ses propriétés ont permis une telle étude. En effet, les faibles densités atomiques impliquent qu’il n'y a pas de diffusion multiple de photons d’une part, et la faible masse et la faible largeur de la transition 23S1 -> 23P2 rend inefficace les processus de refroidissement sous la limite Doppler. Ces conditions nous ont permis d’observer pour la première fois à trois dimensions un gaz refroidit dans le régime Doppler.Le quatrième chapitre présente une étude sur les collisions dans un piège magnéto-optique d’Hélium métastable. Les collisions Penning induites par la lumière, en particulier à des intensités élevées et à des fréquences proches de la fréquence de transition, sont responsables de pertes élevées d’atomes piégés. Nous mesurons le coefficient de taux associé à ces pertes, Ksp = 2,8 ± 0,4 x 10-7cm3/ sThis thesis describes the work done over the past three and a half years on the new metastable helium experiment at the Institut d'Optique in Palaiseau. In the first chapter it describes a study to improve both the efficiency and the accuracy of the Microchannel Plate (MCP) detection system. We have experimented with adding a gold layer on the top of the input plate, something that we have found increases the efficiency but also decreases the accuracy. The addition of a voltage between the two stacked plates has been shown to both raise the efficiency and improve the accuracy in non-coated MCPs.The second chapter is devoted to the construction of the experimental apparatus. Here the excitation of ground state helium to its metastable state is described, as well as the subsequent collimation and cooling by Zeeman slower of the resulting hot atomic beam. The slowed beam is then captured in a Magneto-Optical Trap, in which we have captured 8x108 atoms.In the third chapter an original study on three-dimensional Doppler cooling in a red-detuned molasses and in the Magneto-Optical trap is presented. The metastable helium system is unique as there is no multiple scattering of photons and there are no sub-Doppler effects. This allows for a never before seen experimental realisation of pure Doppler cooling theory. The fourth chapter describes a study on collisions in a magneto-optical trap of metastable helium. Light-induced Penning collisions are responsible for high trap losses at high intensities and at frequencies close to the transition frequency. We measure the constant rate coefficient to Ksp = 2.8 ± 0.4 x 10-7cm3/s
34
Franco, Adenize Aparecida. "Labirintos perdidos: ficção contemporânea em trânsito nos romances de Bernardo Carvalho e Francisco José Viegas (2000-2010)." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/8/8156/tde-27012014-104758/.
Abstract:
Esta tese investiga de que forma a ficção contemporânea de língua portuguesa encontra possibilidades de resistência à crise do romance que tem se estabelecido na contemporaneidade. As obras dos autores Bernardo Carvalho e Francisco José Viegas, inscritos no início do século XXI, permitem verificar como a ficção da era atual suplanta a crise da narrativa e inscreve-se como elemento de resistência. Com base nas teorias de Walter Benjamim, Theodor Adorno, Zygmunt Bauman e Andreas Huyssen - acerca do declínio da narrativa e do romance aliadas a questões de deslocamento, memória e identidade procuramos demonstrar que essa ficção responde a um momento de crise e de transição. Assim, a ficção dos autores investigados representa não a crise do romance, antes configurase como romance da crise, justamente por encontrar nas questões conflitantes (transgressão narrativa, deslocamento espacial, diluição da memória e identidades fluídas) os muros para a construção de seu labirinto ficcional.This thesis investigates how the contemporary fiction of Portuguese language meets possibilities of resistance to the crisis of the romance that has established in the contemporaneity. The titles of the authors Bernardo Carvalho and Francisco José Viegas, registered in the beginning of the 21st century, allow examining how the fiction from the current era supplants the narrative crisis and inscribes itself as a resistance element. Based in the theories of Walter Benjamim, Theodor Adorno, Zygmunt Bauman and Andreas Huyssen about the decline of the narrative and the romance allied to questions of displacement, memory and identity we try to demonstrate that this fiction responds to a moment of crisis and transition. Thus, the fiction of the authors investigated represents not the crisis of the romance, before, it configures itself as romance of the crisis, justly for meeting in the conflicting questions (narrative transgression, spatial displacement, dilution of the memory and fluid identities) the walls for the construction of its fictional labyrinth.
35
Collin, Olivier L. "Development of a Novel Tandem Mass Spectrometry Technique for Forensic and Biological Applications." View abstract, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3292877.
36
Nguyen, Thien Ngoc Tran [Verfasser], and Christiane [Akademischer Betreuer] Wolz. "Establishment and evaluation of Staphylococcus aureus strains with integrative reporter-plasmids for detection of cap and agr promoter activity and establishment of a 3D collagen model / Thien Ngoc Tran Nguyen ; Betreuer: Christiane Wolz." Tübingen : Universitätsbibliothek Tübingen, 2018. http://d-nb.info/1168904617/34.
37
Zhou, Yifan, Dániel Apai, Ben W. P. Lew, and Glenn Schneider. "A Physical Model-based Correction for Charge Traps in the Hubble Space Telescope’s Wide Field Camera 3 Near-IR Detector and Its Applications to Transiting Exoplanets and Brown Dwarfs." IOP PUBLISHING LTD, 2017. http://hdl.handle.net/10150/625388.
Abstract:
The Hubble Space Telescope Wide Field Camera 3 (WFC3) near-IR channel is extensively used in time-resolved observations, especially for transiting exoplanet spectroscopy as well as. brown dwarf and directly imaged exoplanet rotational phase mapping. The ramp effect is the dominant source of systematics in the WFC3 for time-resolved observations, which limits its photometric precision. Current mitigation strategies are based on empirical fits and require additional orbits to help the telescope reach a thermal equilibrium. We show that the ramp-effect profiles can be explained and corrected with high fidelity using charge trapping theories. We also present a model for this process that can be used to predict and to correct charge trap systematics. Our model is based on a very small number of parameters that are intrinsic to the detector. We find that these parameters are very stable between the different data sets, and we provide best-fit values. Our model is tested with more than 120 orbits (similar to 40 visits) of WFC3 observations. and is proved to be able to provide near photon noise limited corrections for observations made with both staring and scanning modes of transiting exoplanets as well as for starting-mode observations of brown dwarfs. After our model correction, the light curve of the first orbit in each visit has the same photometric precision as subsequent orbits, so data from the first orbit no longer need. to. be discarded. Near-IR arrays with the same physical characteristics (e.g., JWST/NIRCam) may also benefit from the extension of this model if similar systematic profiles are observed.
38
Cannon, Ammie. "Controversial Politics, Conservative Genre: Rex Stout's Archie-Wolfe Duo and Detective Fiction's Conventional Form." BYU ScholarsArchive, 2006. https://scholarsarchive.byu.edu/etd/469.
Abstract:
Rex Stout maintained his popular readership despite the often controversial and radical political content expressed in his detective fiction. His political ideals often made him many enemies. Stances such as his ardent opposition to censorship, racism, Nazism, Germany, Fascism, Communism, McCarthyism, and the unfettered FBI were potentially offensive to colleagues and readers from various political backgrounds. Yet Stout attempted to present radical messages via the content of his detective fiction with subtlety. As a literary traditionalist, he resisted using his fiction as a platform for an often extreme political agenda. Where political messages are apparent in his work, Stout employs various techniques to mute potentially offensive messages. First, his hugely successful bantering Archie Goodwin-Nero Wolfe detective duo—a combination of both the lippy American and the tidy, sanitary British detective schools—fosters exploration, contradiction, and conflict between political viewpoints. Archie often rejects or criticizes Wolfe's extreme political viewpoints. Second, Stout utilizes the contradictions between values that occur when the form of detective fiction counters his radical political messages. This suggests that the form of detective fiction (in this case the conventional patterns and attitudes reinforced by the genre) is as important as the content (in this case the muted political message or the lack of overt politics) in reinforcing or shaping political, economic, moral, and social viewpoints. An analysis of the novels The Black Mountain (1954) and The Doorbell Rang (1965) and the novellas "Not Quite Dead Enough" and "Booby Trap" (1944) from Stout's Nero Wolfe series demonstrates his use of detective fiction for both the expression of political viewpoints and the muting of those political messages.
39
Hübner, Ines [Verfasser], Stephan A. [Akademischer Betreuer] Sieber, William [Gutachter] Wuest, Cathleen [Gutachter] Zeymer, and Stephan A. [Gutachter] Sieber. "Elucidating the mechanism of action of the natural product xanthocillin X & tailored cofactor traps for the in situ detection of hemithioacetal-forming pyridoxal kinases / Ines Hübner ; Gutachter: William Wuest, Cathleen Zeymer, Stephan A. Sieber ; Betreuer: Stephan A. Sieber." München : Universitätsbibliothek der TU München, 2021. http://d-nb.info/1231434635/34.
40
Gherardi, David Mark. "Studies of particle and atom manipulation using free space light beams and photonic crystal fibres." Thesis, St Andrews, 2009. http://hdl.handle.net/10023/703.
41
Gorde, Dnyaneshwar R. "System Design For Non-Destructive Detection Of Ions In A Paul Trap Mass Spectrometer." Thesis, 2004. https://etd.iisc.ac.in/handle/2005/1208.
42
Gorde, Dnyaneshwar R. "System Design For Non-Destructive Detection Of Ions In A Paul Trap Mass Spectrometer." Thesis, 2004. http://etd.iisc.ernet.in/handle/2005/1208.
43
HE, TANG CHUEN, and 唐川禾. "Determination of Organotin in Water by Purge and Trap Gas Chromatography-Flame Ionization Detection." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/00031685326258811126.
Abstract:
碩士國立中山大學
海洋資源學系
88
Abstract Organotin compounds have been extensively used in agriculture and industry. The utilization of tributyltin(TBT) in marine antifoul-ing paints pollutes water body significantly. Due to the high toxicity of organotins, there are increased concern for marine environments. A purge and trap system coupled to a gas chromatography(GC) equipped with a flame ionization detector(FID) was used to analyze organotin compounds in water samples. Hydride derivation of orga-notin compounds is conducted by reacting with 5 % sodium boro-hydride in acidic condition(0.03 N HCl) to give the best result. The sample solution is purged with He gas(175 ml/min) for 20 min. to insure the maximum recovery of volatile organotin hydride derivatives. Salinity of sample solution is also an important factor that affects the magnitude of detection signals. Method detection limits are 0.30, 0.15 and 0.06 ng/ml for mono-butyltin, dibutyltin and tributyltin, respectively, and their relative standard deviations are < 5 %. Recovery percentage for different concentration of tributyltin chloride recovery range is 28.9 ~ 40.2 %. Calibration graphs for three kinds of organotin species are linear in the range of 1-10 ng/ml.
44
Lu, Chun Chang, and 呂君章. "Detection of interface and bulk trap distribution and reliability analysis for advanced MOSFET devices." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/00712953061900505219.
Abstract:
博士國立清華大學
工程與系統科學系
103
As the semiconductor industry approaches the limits of traditional silicon complementary metal-oxide-semiconductor (CMOS) scaling, introduction of novel materials and innovative device structures has become necessary for the future of CMOS. High dielectric constant (high-k) material has been proposed to replace the conventional silicon dioxide as gate dielectrics of MOS devices. High mobility materials are also being considered to replace Si in the channel to achieve higher drive currents and switching speeds. Ge has particularly become of great interest as a channel material, owing to its high bulk hole and electron mobilities. However, the characteristic and extent of charge trapping in the interfacial layer between gate dielectric and silicon have been reported to affect strongly the electrical characteristics of high-k gated MOS devices. Hence, providing an accurate and quick measurement for density and distribution of interface and bulk traps is believed to be a valuable research topic. This work proposes several measurement techniques based on the principle of charge pumping (CP) and provides some discussion in depth for measurement results. A modified CP technique with dynamic drain bias and various gate pulse frequencies is proposed to characterize the distribution profiles of trap generation induced by channel-hot-carrier stress in MOSFETs with high-k gate stack. With dynamic drain biases, the drain depletion region during accumulation can be modulated. Hence, the trap distribution with respect to both dielectric depth and channel location can be characterized as well. The trap generation caused by channel-hot-carrier and constant voltage stresses is also compared. Results indicate that the generation of border trap induced by CVS is small and random distributed though whole channel, while that induced by CHC stress is large and localized around the gate-edge region inside the high-k dielectric. In another study, a stress-and-sense charge pumping (SSCP) technique is proposed to measure the stress induced interface trap (ΔNit) in real time evolution without stress interruption. Results show that the ΔNit measured by this SSCP technique is much higher than that measured by the conventional method. This difference is resulted from the recovery induced by stress interruption during the sensing measurements. The ΔNit measured by SSCP method after interruption is approximately equal to that by the conventional one. The stress induced threshold voltage shift (ΔVth) and ΔNit under varies stress frequencies and duty cycles are also measured. The ΔVth seems to depend on the total stress time of stress pulse only. The ΔNit measured by SSCP with different frequencies and duty cycles are similar. The ΔNit also depends on the total stress time of stress pulse, but not the off time during the non-stress half cycle. In the last study, the interface trap density, bulk trap density and stress induced trap generation of Ge-pMOSFETs with ZrO2 and HfON dielectrics are extracted and compared by CP technique with short transition time and various frequencies. Results show that ZrO2 device has higher interface trap density but lower bulk trap density than HfON device, which implies that ZrO2 device has inferior Ge/dielectric interface but high quality dielectric bulk. The improved reliability characteristics in ZrO2 device can be attributed to the low preexisting bulk trap density which greatly suppress charge trapping in the dielectric bulk.
45
Harper, Courtney. "A genomic approach to splice variant detection, primer design, and identification of gene trap sequence tags." Diss., 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3274657.
46
Su, Tzu Hsiang, and 蘇子翔. "Detection of Interface and Border Trap Distributions and Reliability Analysis for Ge MOSFETs by Charge Pumping Technique." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/udfbt6.
Abstract:
碩士國立清華大學
工程與系統科學系
104
As the scaling of silicon metal-oxide-semiconductor (MOSFET) approach to its limitation with the development of semiconductor industry, novel materials and innovative device structures need to be introduced in future. Ge is promising for a channel material in MOSFET, owing to its high hole and electron mobility. A high quality interface layer is necessary to improve characteristics on Ge-MOSFETs device. Hence, an accurate and quick measurement to detect interface trap density and distribution of bulk traps should be a valuable research topic. Several measurement techniques based on the charge pumping are proposed to detect trap density distributions. In the first study, interface layer with hydrogen treatment and microwave annealing Ge MOSFET devices obtain lower interface trap density and better interface layer quality than without one. The electrical characteristic have higher drive current, mobility, and lower off current, due to interface layer with hydrogen treatment can repair interface traps and microwave annealing can improve PN junction. On the other hand, hydrogen treatment can improve traps density less than depth about 0.8 nm and microwave annealing can obviously reduce traps density higher than depth about 1 nm from distribution profile of border traps density. In the second study, the interface trap density, bulk density and stress induced trap generation of Ge-pMOSFETs with ZrO2 and HfON gate dielectrics are extracted and compared by CP technique. Results show that ZrO2 device has higher interface trap density but lower bulk trap density than HfON device, which implies that ZrO2 device has inferior Ge/dielectric interface but high quality dielectric bulk. The improved reliability characteristics in ZrO2 device can be attributed to the low preexisting bulk trap density which suppresses charge trapping in the dielectric bulk. In the last study, charge pumping technique is used to detect interface and bulk trap distribution and stress induced trap generation of Ge-pMOSFETs with and without Hf buffer layer (HBL). The charge pumping technique confirm that device with HBL has lower interface and bulk traps density than device without, which show electrical characteristic can be improved. Results show that device with HBL has better performance from NBTI and PBTI reliability analysis because of it has higher quality of interface characteristics and dielectric bulk.
47
Lin, Wei-Ting, and 林威廷. "A Study on The Detection and Recognition of Wild-Animals in Camera-Trap Images with Deep Learning." Thesis, 2019. http://ndltd.ncl.edu.tw/cgi-bin/gs32/gsweb.cgi/login?o=dnclcdr&s=id=%22107NCHU5394033%22.&searchmode=basic.
Abstract:
碩士國立中興大學
資訊科學與工程學系所
107
In recent years, more and more biologists and natural scientists have set up camera traps in the wild to collect wild animal images in large volume. In the way of using camera-trap to collect wildlife images, people do not need to wait for a long time in a fixed place until animals appear. However, in order to analyze these images and videos collected by camera-trap, and if this work is processed manually, it may require a lot of time and money. In addition, the speed of collecting wildlife images and videos is so fast that the biologists can’t effectively use the collected data. With the development of deep learning in computer vision in recent years, in this paper we propose a deep learning and image processing techniques to detect and identify animals in the wild, aiming to establish an automatic detection system for wild animals. In the wild, animals are often covered by some grass or branches, which makes it impossible to identify with the deep learning method. Therefore, in the wildlife recognition system, we combined the traditional image processing method. We use the hierarchical median filter to build the background model, and background subtraction technique to obtain animals which are covered by grass or branches. After getting the animals, we will use the VGG16 and darknet53 classifiers to classify them. The images and videos used in this study were provided by the professor Chen of the Department of Forest, National Chung Hsing University. Experimental results show that the animals covered by some grass or branches can still be identified successfully. It demonstrates the effectiveness of the proposed method.
48
Graichen, Adam. "Enhanced detection strategies accomplished through metal binding and miniature mass spectrometry." 2013. https://scholarworks.umass.edu/dissertations/AAI3556252.
Abstract:
A multiplexed method for performing MS/MS on multiple ions simultaneously in a miniature rectilinear ion trap (RIT) mass spectrometer has been developed. This method uses an ion encoding procedure that relies on the mass bias that exists when ions are externally injected into an RIT operated with only a single phase RF applied to one pair of electrodes. The ion injection profile under such conditions ions is Gaussian-like over a wide range of RF amplitudes, or low mass cutoff (LMCO) values, during ion accumulation. We show that this distribution is related to ion m/z, and is likely caused by ions having an optimal range of pseudo-potential well depths for efficient trapping. Based on this observation, precursor ion intensity changes between two different injection LMCO values can be predicted, and these ion intensity changes are found to be carried through to their corresponding product ions, enabling multiplexed MS/MS spectra to be deconvoluted. The gas-phase reactions of a series of coordinatively unsaturated [Ni(L) n]y+ complexes, where L is a nitrogen-containing ligand, with chemical warfare agent (CWA) simulants in a miniature rectilinear ion trap mass spectrometer were investigated as part of a new approach to detect CWA. Results show that the metal complex ions can react with low concentrations of several CWA simulants, including dipropyl sulfide (simulant for mustard gas), acetonitrile (simulant for the nerve agent tabun), and diethyl phosphite (simulant for nerve agents sarin, soman, tabun, and VX), thereby providing a sensitive means of detecting these compounds. The [Ni(L)n] 2+ complexes are found to be particularly reactive with the simulants of mustard gas and tabun, allowing their detection at low parts-per-billion (ppb) levels. These detection limits are well below the median lethal doses for these CWAs, which indicates the applicability of this new approach, and are about two orders of magnitude lower than electron ionization detection limits on the same mass spectrometer. The use of coordinatively unsaturated metal complexes as reagent ions offers the possibility of further tuning the ion-molecule chemistry so that desired compounds can be detected selectively or at even lower concentrations. Mass spectrometry has become a tool for studying noncovalently bound complexes. Specifically, electrospray ionization mass spectrometry (ESI-MS) has found increasing use for the determination of affinity (Ka) or dissociation (Kd) constants. Direct measurement of the equilibrium components by ESI-MS is the most straightforward approach for determining binding equilibrium constants, but this approach is prone to error and has some inherent limitations. Transferring complexes from solution to the gas phase may perturb the equilibrium concentrations and/or different ionization efficiencies may cause the resulting ion signals not to reflect actual solution concentrations. Furthermore, ESI only works under a limited range of solvent conditions (i.e. low ionic strengths), which limits the broad applicability of this approach. We propose an approach based on covalent labeling in the context of metal-catalyzed oxidation (MCO) reactions that, when combined with MS, overcomes such limitations when determining metal-ligand binding constants. The MCO-MS approach will provide concurrent information regarding metal binding site and metal-protein binding affinity. Optimization of the MCO reaction through isotopic mass tags will permit enhanced identification of modified residues. Application of this method to study the affinity and binding interactions of other divalent metals with β2m are likely to provide insight into the specificity of copper for causing β2m amyloid formation.
49
Liang, Shao-Yu, and 梁少瑜. "Measuring masses of single bacterial whole cells with laser induced acoustic desorption plasma charge detection quadrupole ion trap mass spectrometer." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/54633426705005600119.
Abstract:
碩士國立東華大學
物理學系
104
The mass measurement of bio-particles with sizes from 50 nm to 3 um is still challenging in mass spectrometric field. In our previous study, we found charge detection quadrupole ion trap mass spectrometer (CD-QIT MS) could measure the mass and mass distribution of cells larger than 3 um with laser induced acoustic desorption (LIAD) method. Here we develop a new LIAD plasma (LIADP) with Ar mix methane gas as ion source to allow ionization of intact bacteria containing several thousands of charge number. We also compare different result by changing experiment condition of Quadrupole Ion Trap (QIT). The individual mass, charge, and mass distribution of polystyrene particles from 2 um to 0.3 um are measured for mass calibration. Escherichia coli and Staphylococcus aureus cells are measured and the average charge is about 1300.
50
Han, Chou-Hsun, and 韓宙勳. "Measuring intact mass and mass distribution of bacteria particles with a laser induced plasma charge detection quadrupole ion trap mass spectrometer." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/81897330369045454107.
Abstract:
碩士國立東華大學
物理學系
104
The sizes of large biomolecules and bioparticles are in the range from 1 nm to 100 m. These large biomolecules and bioparticles include protein complexes, viruses, bacteria and cells. So far the highest mass that a quadrupole time-of-flight mass spectrometer can measure is HK97 capsids with mass of 18 MDa (size ~50 nm) and charge of 350 using the electrospray ion source (ESI)[1]. For sizes greater than 3 m, a charge detection quadrupole ion trap mass spectrometer (CD-QIT MS) can measure the mass and mass distribution of cells with laser induced acoustic desorption (LIAD) ion source[2]. But measurement of the sizes from 50 nm to 3 m is still very challenging for mass spectrometric scientists. Although mass of single bacteria and viruses can be measured with a quadrupole ion trap by light scattering method from sizes 80 nm to several m, but the measuring speed is too slow to be widely used for practical consideration.[3] Here, we propose for the first time a laser-induced plasma (LIP) ion source to enhance the charges of bacteria particles up to few thousands. With LIP ion source, the intact mass of bacteria and their mass distribution can be measured with CD-QIT MS. Several bacteria were measured including Staphylococcus aureus, Escherichia coli and the measured mass and mass distribution is in consistent with their size distribution measured by the optical microscope method. The charge number is enhanced about one order of magnitude as compared to LIAD method