• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 341
  • 124
  • 71
  • 52
  • 48
  • 29
  • 20
  • 9
  • 3
  • 3
  • 3
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 843
  • 109
  • 84
  • 64
  • 56
  • 54
  • 49
  • 48
  • 46
  • 44
  • 44
  • 43
  • 42
  • 39
  • 38
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Graphic film: a new genre of moving image

Sheffield, Adam T Unknown Date (has links)
Over the past three years I have engaged in a search for a form of moving image that would serve as a medium to contain, express and communicate my concerns and ideas. My initial investigations led me to motion graphics but as my understanding of moving image broadened I came to the conclusion that the models I was examining did not fit this genre, they are something new and do not have a definition. There are conflicting ideas about what the term motion graphics means. For the purpose of clarity, I adopted Matt Frantz's definition as a start point: "designed, non-narrative, non-figurative based visuals that change over time." Motion graphics is often considered a component of a larger moving image work or a filler element between two larger works. For example, the opening moments of a film or television programme, or a swirling abstract that forms a background for an interstitial between programmes. I require a description of a moving image type of that can be used as a guide to making work. Research into the field of moving image work made by designers was conducted with grounded theory employed as the principle methodology. This research has revealed a moving image type that I refer to as "graphic film". During the past year I have identified its key characteristics. I have explored and tested the boundaries of this new genre by constructing graphic film and comparing it to previously defined forms of moving image. The outcome of this project is a comprehensive description of what graphic film is and its ten primary characteristics. This project can serve as a guide for other graphic designers who wish to make work of this type.
142

Modeling the extrinsic resistance and capacitance of planar and non-planar MOSFETs /

Wu, Wen. January 2007 (has links)
Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2007. / Vita. Includes bibliographical references (leaves 134-143). Also available in electronic version.
143

Crosstalk Between the Planar Cell Polarity and Hedgehog Signaling Pathways Influences Satellite Cell Fate

Freeman, Emily 16 January 2019 (has links)
Our laboratory has identified two secreted proteins, Wnt7a and Sonic hedgehog (Shh), that regulate satellite cell (SC) fate, during muscle differentiation. While Wnt7a stimulates symmetric SC division through the planar cell polarity (PCP) pathway, Shh activates Myf5 expression in the committed SC following asymmetric division through cilia-mediated Hedgehog (Hh) signaling. Crosstalk between these pathways has been well characterized during development, and is likely to be conserved in muscle regeneration. Indeed, accumulating evidence suggests the PCP pathway influences primary cilia formation, an organelle required for proper Hh signal transduction. Here we show that Wnt7a treatment in primary myoblasts increases the presence of primary cilia. Additionally, using myofiber culture, we demonstrate that Wnt7a increases myogenin (MyoG) expression. Removal of primary cilia through a small interfering RNA (siRNA) targeted towards IFT88 impedes Wnt7a mediated MyoG expression, suggesting crosstalk between the PCP and Hh pathways facilitates muscle differentiation. Furthermore, through siRNA knockdown we have identified the downstream PCP effectors, Inturned and Fuzzy as the main candidates responsible for this crosstalk. Knockdown of either Inturned or Fuzzy impedes Wnt7a-mediated MyoG expression. Taken together our data demonstrates crosstalk between the PCP pathway and Hh signaling regulates the differentiation of SCs.
144

Thermometry of flow fields using a two-color ratiometric PLIF technique

Heronemus, Seth M. January 1900 (has links)
Master of Science / Department of Mechanical and Nuclear Engineering / Steven Eckels / In this thesis, a two-color ratiometric planar laser-induced fluorescence (PLIF) technique for the measurement of temperature fields in liquids is described. The method uses the temperature sensitive rhodamine B and temperature insensitive rhodamine 110 fluorescent dyes. The ratio of the fluorescent emission intensity of these two dyes is inversely proportional to temperature and is independent of laser intensity variation in the flow field. Because the emission spectra of these two dyes overlap, a correction was developed to disentangle the two signals. In addition, the absorption spectra of rhodamine B and rhodamine 110 and emission spectrum of rhodamine 110 overlap, leading to the self-attenuation of the rhodamine 110 signal by the dye solution. A correction with respect to path length was developed for self-attenuation. This thesis presents the calibration process for a PLIF thermometry system and visualization of temperature gradients in a glass water tank with motion induced by large temperature gradients. A step-by-step procedure of the final calibration process is also presented.
145

Polotělesa a planární funkce / Semifields and planar functions

Hrubešová, Tereza January 2018 (has links)
The aim of this diploma thesis is to introduce the topic of semifields and to explain its connection with planar functions. From its beginning the thesis leads to the formulation of relation between commutative se- mifields of odd order and planar Dembowski-Ostrom polynomials, which R. S. Coulter and M. Henderson introduce in their article from 2008. At the beginning of the thesis there is a short introduction to projective and affine planes. The thesis further describes coordinatization of projective plane by planar ternary ring. It also aims to investigate properties of ternary ring depending on the number of perspectivities in the projective plane. One of the chapters is dedicated to the isotopy of loops, which can be applied directly on the isotopy of semifields. The thesis mainly focuses on the proof of denoted correspondence between commutative semifields of odd order and planar Dembowski-Ostrom polynomials. Finally, several corrolaries of this relation and the isotopy of semifields are declared. 1
146

Configurações centrais do problema planar de 1+n corpos

dos Santos Oliveira, Allyson 31 January 2011 (has links)
Made available in DSpace on 2014-06-12T15:48:46Z (GMT). No. of bitstreams: 2 arquivo2712_1.pdf: 459734 bytes, checksum: 434353915f1d98cbd01c9891017a9d9a (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Neste trabalho estamos interessados nas configurações centrais do problema planar de 1+n corpos. Este é um caso restrito do problema planar de N corpos no qual temos um corpo de massa grande e os n demais possuem massas infinitesimais. Apresentamos os principais resultados sobre tal problema e também contribuições novas sobre a simetria das configurações centrais no caso n = 5 e a classificação completa das configurações centrais empilhadas com a adição de um ou dois novos satélites
147

Caracterização das incertezas e limitações dos métodos de quantificação de atividade baseada em imagens

Maria Pereira, Jucilene 31 January 2009 (has links)
Made available in DSpace on 2014-06-12T23:13:34Z (GMT). No. of bitstreams: 2 arquivo2649_1.pdf: 1468078 bytes, checksum: ce4d110c6332d8130a6b30314d29a3d4 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009 / O objetivo deste trabalho foi avaliar as incertezas e limitações de ambos os métodos de quantificação de imagens, planar e SPECT, e propor correções para melhorar a exatidão na quantificação de atividade baseada no uso de imagens com o propósito de realizar cálculos de dosimetria interna também mais exatos. Neste trabalho, três fantomas que representaram geometrias de diferentes graus de complexidade (esferas, região do miocárdio e região do torso), foram usados para estudar as incertezas e as limitações de cada método com respeito ao tamanho, ao volume, à atividade contida no objeto, à presença de background, entre outras variáveis. O desempenho da quantificação foi avaliado para as imagens realizadas com três importantes radionuclídeos usados na rotina clinica : o 99mTc, o 111In e o 131I. Os resultados mostraram que, apesar do efeito do volume parcial constituir um importante fator para a subestimação da atividade quantificada com as imagens SPECT, a quantificação de atividade realizada com este método apresentou as menores variações dos valores conhecidos de atividade através dos diferentes níveis de background e das diferentes concentrações usadas quando comparados aos valores apresentados pelo método planar. Quando todas as correções são aplicadas à imagem SPECT, a subtração de background passa a ser o fator que causa a maior incerteza na quantificação da atividade e o erro associado a este fator pode ser reduzido realizando-se uma caracterização da sua influência na quantificação da atividade em função do tamanho do objeto. Os resultados sugerem que o uso de imagens SPECT deve ser preferido ao de imagem planar para a quantificação de atividade quando estudos dosimétricos envolvendo pequenos objetos (<11 ml) são realizados, pois fornece resultados mais confiáveis
148

Vícepásmová anténa pro GSM (900/1800) / Multiband antenna for GSM (900/1800)

Kalánek, Jakub Unknown Date (has links)
This work deals with the principles on which they are based multiband antennas, especially for GSM (900/1800). It then focuses on different ways you can implement these multi-band antennas, mainly deals with structures that can be easily realized using planar technology. These antennas was designed and optimized in electromagnetic simulation software. Selected antenna was practically realized.
149

Tunable Combline Filter and Balun: Design, Simulation, and Test

Ramirez, Daniel Alex 23 March 2017 (has links)
Reconfigurable filters are an attractive solution for many military and commercial applications due to their ability to alter the partitioned frequency band in an RF system without requiring a bank of fixed filters. The onset of this technology has the potential to revolutionize the RF industry by allowing for agile devices which consume less size, weight, and power while providing greater performance. However, at the present state, reconfigurable filters present a reduction in performance when compared to filter banks. This has led to exciting research in the field of RF tunable filters. For many applications, planar reconfigurable filters have been utilized due to their low cost of manufacturing and ease of implementation in a system. One topology that has proven to be versatile in design is the combline filter which employs line resonators loaded with a capacitor to obtain a predetermined response. To implement a varying center frequency reconfigurable combline filter, the resonator is loaded with a capacitance that can be tuned either digitally or continuously by presenting a DC voltage. Due to their ease of use and availability, varactors are a common choice as they provide a continuously tunable capacitance by presenting a reverse bias voltage to the device. To continue the trend of lowering size, weight and power while maintaining high vitality in performance, consolidation of RF components may prove to be a good next step. Tunable balun filters have already been presented as a viable option for consolidation of components and show good performance. However, those designs which have been presented do not demonstrate a topology that can implement higher than a second order filter. This project, for the first time, investigates the consolidation of the Marchand balun and the combline filter into a single topology which allows for quick adaption of higher order filters while maintaining vigor in performance. A design is presented which achieves 25% tuning bandwidth centered at 1.5 GHz with less than 5 dB insertion loss, a phase balance of 180 ± 1° and an amplitude difference of ± 0.6 dB.
150

Design and simulation of planar electronic nanodevices for teraherz and memory applications

Ali, Mubarak January 2013 (has links)
The performances derived from current electronic technology are fast approaching a plateau since traditional vertically-layered devices are already in the scaling-limit range. The prospects of using planar devices as a solution have become increasingly promising. Besides, they provide additional advantages of being simple yet operating at very high speeds. In this study, the feasibility of utilising a planar nanoscale unipolar diode or a self-switching device (SSD) for terahertz emission and memory applications is demonstrated using simulations. Detailed characterisation of the devices is performed, paying close attention to their geometrical parameters and the surface-charge density which are crucial in planar electron transport.The emission from the SSD is profiled using electron dynamics in the device evidencing the presence of Gunn domains that lead to current oscillations. Following this, the device performance as determined by lithography-tuneable parameters of channel-length, channel-width and interface-charge density is investigated, in terms of their oscillating frequencies and current amplitudes. The study shows that the geometrical dimensions of the SSD can be tailored for optimum emission frequency and current oscillation magnitude, simply by altering the length and width of the channel, respectively. The highest fundamental frequency attained is 0.2 THz and higher harmonics could achieve up to 1 THz. Moreover, the interface-charge density has a much greater effect on the oscillation frequency than expected, providing some promise to extend emission frequency to a range that has been difficult to achieve using a solid-state device at room temperature.The flexibility of the SSD design has been further exploited to conceptualise a novel planar memory device aimed at overcoming the stagnated processing speeds of multilayer computational chips relying on interconnects. The structure is based on a high surface-to-volume ratio which enables conduction to be controlled by a memory storage region that can be charged and discharged by a control gate. Initially, structure dimensions are tuned and thereafter, the memory retention times resulting from the optimisation of geometrical and electrical parameters are discussed. The energy consumption of the device is much lower than flash memories, potentially useful for emerging low-power applications, particularly when device arrays are designed.

Page generated in 0.0467 seconds