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The Global ETD Search service is a free service for researchers
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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.
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Showing 81 to 90 of 92 (0.014 seconds)| 81 |
Étude, élaboration et caractérisation d'hétérostructures «auto-protégées» à base d'ondes élastiques / Study, elaboration and characterization of packageless heterostructures based on elastic waveLegrani, Ouarda 14 November 2012 (has links)
L'objectif de cette thèse est de réaliser des hétérostructures packageless par l'intermédiaire d'une couche protectrice contre les environnements atmosphériques néfastes tels que l'oxydation et l'humidité mais aussi dans les milieux agressifs à hautes températures. La première hétérostructure envisagée dans cette étude, utilise le principe des ondes isolées. Le silicium a été employé en combinaison avec le ZnO car il offre de bonnes propriétés électroacoustiques mais aussi la possibilité de travailler à de hautes fréquences. Ainsi, cette configuration AlN/IDT/ZnO/Si a été principalement choisie pour des applications en environnements néfastes et intégrable dans la technologie CMOS. Par ailleurs, une couche de protection d'AlN permettra à l'onde de se confiner dans la couche active de ZnO et de rester insensible à la surface mais sensible à la température. Le ZnO étant toutefois conducteur à haute température (> 400°C), cette hétérostructure reste peut applicable en milieux sévères à haute température. C'est pourquoi une seconde hétérostructure packageless utilisant comme base l'IDT/AlN/Saphir a été étudiée dans ce manuscrit. Il s'agit donc de protéger les IDTs par un film mince contre les phénomènes d'agglomération des électrodes à hautes températures (1000 °C) / The objective of this thesis is to realize heterostructures packageless through a protective layer against harmful atmospheric environments such as oxidation and moisture and also in aggressive environments (high temperatures). The first heterostructure considered in this study, uses the principle of wave isolated. Silicon was used in combination with ZnO as it offers good performances and the possibility to work at high frequencies. Thus, this configuration AlN/IDT/ZnO/Si was chosen for applications in environments with harmful and integrated in CMOS technology. In addition, a protective layer of AlN allows the wave is confined in the active layer of ZnO and remains insensitive to the surface but sensitive to temperature. However, ZnO is conductive at high temperature (> 400 ° C) wich is limited her utilization in harsh environments. This is why a second packageless heterostructure using the IDT/AlN/sapphire has been studied in this manuscript. It is therefore to protect the IDTs by a thin film against the phenomena of agglomeration of the electrodes at high temperatures (1000 ° C)
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Qubit control-pulse circuits in SOS-CMOS technology for a Si:P quantum computerEkanayake, Sobhath Ramesh, Electrical Engineering & Telecommunications, Faculty of Engineering, UNSW January 2008 (has links)
Microelectronics has shaped the world beyond what was thought possible at the time of its advent. One area of current research in this field is on the solid-state Si:P-based quantum computer (QC). In this machine, each qubit requires an individually addressed fast control-pulse for non-adiabatic drive and measure operations. Additionally, it is increasingly becoming important to be able to interface nanoelectronics with complementary metal-oxide-semiconductor (CMOS) technology. In this work, I have designed and demonstrated full-custom mixed-mode and full-digital fast control-pulse generators fabricated in a silicon-on-sapphire (SOS) CMOS commercial foundry process ?? a radio-frequency (RF) CMOS technology. These circuits are, fundamentally, fast monostable multivibrators. Initially, after the design specifications were decided upon, I characterized NFET and PFET devices and a n+-diffusion resistor from 500 nm and 250 nm commercial SOS-CMOS processes. Measuring their conductance curves at 300 300 K, 4.2 2 K, and sub-K (30 30 mK base to 1000 1000 mK) showed that they function with desirable behaviour although exhibiting some deviations from their 300 300 K characteristics. The mixed-mode first generation control-pulse generator was demonstrated showing that it produced dwell-time adjustable pulses with 100 100 ps rise-times at 300 K, 4.2 2 K, and sub-K with a power dissipation of 12 12 uW at 100 100 MHz. The full-digital second generation control-pulse generator was demonstrated showing accurately adjustable dwell-times settable via a control-word streamed synchronously to a shift-register. The design was based on a ripple-counter with provisions for internal or external clocking. This research has demonstrated that SOS-CMOS technology is highly feasible for the fabrication of control microelectronics for a Si:P-based QC. I have demonstrated full-custom SOS-CMOS mixed-mode and full-digital control circuits at 300 300 K, 4.2 2 K, and sub-K which suitable for qubit control.
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Controlled delamination of metal films by hydrogen loading / Kontrollierte Ablösung dünner metallischer Schichten durch WasserstoffbeladungNikitin, Eugen 18 November 2008 (has links)
No description available.
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Qubit control-pulse circuits in SOS-CMOS technology for a Si:P quantum computerEkanayake, Sobhath Ramesh, Electrical Engineering & Telecommunications, Faculty of Engineering, UNSW January 2008 (has links)
Microelectronics has shaped the world beyond what was thought possible at the time of its advent. One area of current research in this field is on the solid-state Si:P-based quantum computer (QC). In this machine, each qubit requires an individually addressed fast control-pulse for non-adiabatic drive and measure operations. Additionally, it is increasingly becoming important to be able to interface nanoelectronics with complementary metal-oxide-semiconductor (CMOS) technology. In this work, I have designed and demonstrated full-custom mixed-mode and full-digital fast control-pulse generators fabricated in a silicon-on-sapphire (SOS) CMOS commercial foundry process ?? a radio-frequency (RF) CMOS technology. These circuits are, fundamentally, fast monostable multivibrators. Initially, after the design specifications were decided upon, I characterized NFET and PFET devices and a n+-diffusion resistor from 500 nm and 250 nm commercial SOS-CMOS processes. Measuring their conductance curves at 300 300 K, 4.2 2 K, and sub-K (30 30 mK base to 1000 1000 mK) showed that they function with desirable behaviour although exhibiting some deviations from their 300 300 K characteristics. The mixed-mode first generation control-pulse generator was demonstrated showing that it produced dwell-time adjustable pulses with 100 100 ps rise-times at 300 K, 4.2 2 K, and sub-K with a power dissipation of 12 12 uW at 100 100 MHz. The full-digital second generation control-pulse generator was demonstrated showing accurately adjustable dwell-times settable via a control-word streamed synchronously to a shift-register. The design was based on a ripple-counter with provisions for internal or external clocking. This research has demonstrated that SOS-CMOS technology is highly feasible for the fabrication of control microelectronics for a Si:P-based QC. I have demonstrated full-custom SOS-CMOS mixed-mode and full-digital control circuits at 300 300 K, 4.2 2 K, and sub-K which suitable for qubit control.
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Molecular Rearrangements at Polymeric Interfaces Probed by Sum Frequency SpectroscopyKurian, Anish 21 April 2011 (has links)
No description available.
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And the Stereotype Award Goes to...: A Comparative Analysis of Directors using African American Stereotypes in FilmYoung, Kelcei 12 1900 (has links)
This study examines African American stereotypes in film. I studied six directors, Kathryn Bigelow, Spike Lee, the Russo Brothers, Ryan Coogler, Tate Taylor, and Dee Rees; and six films Detroit, BlacKkKlansman, Captain America: The Winter Soldier, The Help, and Mudbound. Using the framework of critical race theory and auteur theory, I compared the common themes between the films and directors. The main purpose of my study is to see if White or Black directors predominantly used African American stereotypes. I found that both races of directors rely on stereotypes for different purposes. With Black directors, the stereotype was explained further through character development, while the White directors used the stereotype at face value with no further explanation.
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Characterization of the Performance of Sapphire Optical Fiber in Intense Radiation Fields, when Subjected to Very High TemperaturesPetrie, Christian Matthew 10 October 2014 (has links)
No description available.
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Herstellung von GaN-Schichten mittels Hochtemperatur-GasphasenepitaxieSchneider, Tom 03 August 2022 (has links)
Verbindungshalbleiter mit einer großen Bandlücke wie Galliumnitrid (GaN) sind aufgrund ihrer hervorragenden elektronischen Eigenschaften für die Halbleiterindustrie von großem Interesse. Die Hochtemperatur-Gasphasenepitaxie, die auf dem physikalischen Gasphasentransport von Gallium basiert, ist eine alternative Methode der Gasphasenepitaxie von GaN. Im Mittelpunkt der vorliegenden Arbeit standen die Weiterentwicklung der Methode hinsichtlich der Verringerung der Kontamination und die Reduzierung der Versetzungsdichte in den GaN-Schichten. Dazu wurde eine neue Verdampfungszelle entwickelt und die komplexen, mehrstufigen Nukleations- und Wachstumsprozesse systematisch untersucht. Insgesamt wurden zu kommerziell verfügbaren GaN-Schichten vergleichbare Defektdichten erreicht. Zusätzlich wurde die Methode zur Abscheidung auf Saphir-Substraten mit einem Durchmesser von bis zu 2 Zoll aufskaliert.
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以專利分析之觀點探討LED製程技術對中國LED產業及市場的影響 / The impact of LED manufacturing process technology on LED industry and market in China: patent analysis perspective洪駿之, Hung, Jackson Unknown Date (has links)
在二十一世紀中， LED發光二極體更是備受期待的節能產品。過去背光源一直是LED主要應用項目，而漸漸地照明也開始採用LED產品，甚至各國已宣布將禁用白熾燈。然而，在各國政府及業者大力推廣及投入LED產業之際，目前LED產品尚未能實現市場替代效應之事實卻不容忽視。細究其可能原因，是否LED產品仍有技術功能缺陷，抑或其價格無法競爭，又者消費者對產品認知不足、終端通路尚未成熟、品牌塑造尚待建立等因素，讓消費者暫時裹足不前?
鑒於台灣在LED產業中已有完整的上中下游布局，不但是下游封裝的全球最大供應中心，近年更也逐步紮根中游晶粒產品，甚至切入上游單晶基板、磊晶產品製程。故此，本研究希冀探查現有LED產品所遭遇之困難，以功能品質及經濟價值等角度，找尋可突破市場瓶頸之關鍵因素，並針對其中可進行專利檢索及分析的較具技術性因素：LED單晶基板，以中國大陸此成長最為顯著之市場作為專利檢索及分析之核心地理區域，探討LED單晶片基板之專利發展趨勢以及研發參考目標及方向。
在進行專利檢索之前，本研究將先行剖析現有LED單晶片基板的應有功能、重點特性、4大類基板材料選擇與其最新研發優勢，包含藍寶石、碳化矽、矽、氮化鎵，以助於後續專利檢索及分析結果之觀察思考。本研究的結論與建議將分別針對不同的LED單晶片基板材料選擇，以專利分析結果對照其市場發展近況，向台灣業者提出藍寶石、碳化矽已係過度競爭、不宜進入的項目，並在最後建議台灣業者仍可持續投入研發LED矽、氮化鎵基板材料，以及額外以技術與應用創新增加其產品的市場連結度及應用產業競爭利基。 / Nowadays LED has become a future mainstream of highly expected energy-saving product. Back-lighting has been the main application for LED, such as in monitors, and furthermore lighting has grown its market size into significance. However, it should draw attention that LED products has not yet fully replace conventional lighting as expected, due to a number of possible factors, including functions, prices, consumer awareness, channeling, and/or branding.
In light of the fully established LED industry in Taiwan, including the largest downstream packaging supply source, mature middle-stream wafer production and leading upstream epitaxy and substrate manufacturing, this study aims to seek and find the patent searchable and analyzable part of the current LED obstacles in product quality and economic value perspective. As a result, single crystal substrate falls into abovementioned criteria, including four major substrate materials: sapphire, silicon carbonate, silicon, and gallium nitrite. This study further concentrates the patent search and analysis on China, the fastest growing LED market among all regions and the biggest opportunity for Taiwan players.
Before patent search, this study gives a detailed elucidation about four substrate materials on functions, important traits, different types and respective R&D updates and breakthrough, followed by interpretation of and association with patent search and analysis. At the end of this study, conclusions and suggestions are given, based on Taiwan players’ current relative strength and weakness. In sum, sapphire substrates and silicon carbonate substrate have overly competitive patent and market situation, and silicon substrates and gallium nitrite substrate may allow Taiwan players to continue and/or reinforce R&D investment. Additionally, technology and application innovation could increase product-market linkage and competitive edge in LED application industry.
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Cooling of electrically insulated high voltage electrodes down to 30 mK / Kühlung von elektrisch isolierten Hochspannungselektroden bis 30 mKEisel, Thomas 07 November 2011 (has links) (PDF)
The Antimatter Experiment: Gravity, Interferometry, Spectroscopy (AEGIS) at the European Organization for Nuclear Research (CERN) is an experiment investigating the influence of earth’s gravitational force upon antimatter. To perform precise measurements the antimatter needs to be cooled to a temperature of 100 mK. This will be done in a Penning trap, formed by several electrodes, which are charged with several kV and have to be individually electrically insulated. The trap is thermally linked to a mixing chamber of a 3He-4He dilution refrigerator.
Two link designs are examined, the Rod design and the Sandwich design. The Rod design electrically connects a single electrode with a heat exchanger, immersed in the helium of the mixing chamber, by a copper pin. An alumina ring and the helium electrically insulate the Rod design. The Sandwich uses an electrically insulating sapphire plate sandwiched between the electrode and the mixing chamber. Indium layers on the sapphire plate are applied to improve the thermal contact. Four differently prepared test Sandwiches are investigated. They differ in the sapphire surface roughness and in the application method of the indium layers.
Measurements with static and sinusoidal heat loads are performed to uncover the behavior of the thermal boundary resistances. The thermal total resistance of the best Sandwich shows a temperature dependency of T-2,64 and is significantly lower, with roughly 30 cm2K4/W at 50 mK, than experimental data found in the literature. The estimated thermal boundary resistance between indium and sapphire agrees very well with the value of the acoustic mismatch theory at low temperatures.
In both designs, homemade heat exchangers are integrated to transfer the heat to the cold helium. These heat exchangers are based on sintered structures to increase the heat transferring surface and to overcome the significant influence of the thermal resistance (Kapitza resistance). The heat exchangers are optimized concerning the adherence of the sinter to the substrate and its sinter height, e.g. its thermal penetration length.
Ruthenium oxide metallic resistors (RuO2) are used as temperature sensors for the investigations. They consist of various materials, which affect the reproducibility. The sensor conditioning and the resulting good reproducibility is discussed as well.
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