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A 2D Indoor Propagation Model Based on Waveguiding, Mode Matching and Cascade CouplingSöderman, Daniel January 2012 (has links)
In this thesis a theoretical model for indoor propagation in a straight corridor with adjacent rooms is developed and evaluated. One objective is to assess the effect of different conductivities and permittivities in the walls between rooms have on the power levels, in both the corridor and the rooms. Furthermore, a model of a leaky cable is proposed for which the corresponding propagation characteristics are evaluated and compared to that of a dipole antenna to assess if a leaky cable is a viable alternative for radio coverage in an indoor environment. In order to evaluate the model, a wideband measurement campaign has been conducted at 2.44 GHz with a 40 meter long leaky coaxial cable and two vertically polarized dipole antennas. The proposed model is based on the waveguide model in 2D, the mode matching method and cascade coupling of scattering matrices. A section of a corridor is modeled as waveguides with different cross section where one waveguide contains a dielectric medium which models the wall between two rooms. Mode matching is used to determine how the waveguide modes are coupled at the boundaries between the waveguides and the result is collected in a scattering matrix. Multiple corridor sections are then connected together, by cascade coupling the corresponding scattering matrices of each section, into a long corridor with adjacent rooms. Point sources are used to excite the waveguides as an approximation of dipole transmitting antennas. Moreover, the radiating slots in the leaky cable are modeled by multiple point sources that are phase and amplitude shifted in order to achieve the same radiation direction and longitudinal loss as the leaky cable. Finally, the inverse discreet Fourier transform is applied to the wideband electromagnetic field distribution in order to determine the propagation characteristics in the time domain. The results from the model are in good quantitative agreement with the measurement data, and it is shown that a leaky cable give a more even radio coverage in an office corridor compared to a dipole antenna, especially when the internal walls are highly reflective. Moreover, it is shown that the direct path is dominating for transmission between rooms with transparent walls, like plasterboard, while the main propagation path for highly reflective walls is along the corridor.
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Aerodynamics of Endwall Contouring with Discrete Holes and an Upstream Purge Slot Under Transonic Conditions with and without BlowingBlot, Dorian Matthew 23 January 2013 (has links)
Endwall contouring has been widely studied as an effective measure to improve aerodynamic performance by reducing secondary flow strength. The effects of endwall contouring with discrete holes and an upstream purge slot for a high turning (127") airfoil passage under transonic conditions are investigated. The total pressure loss and secondary flow field were measured for two endwall geometries. The non-axisymmetric endwall was developed through an optimization study [1] to minimize secondary losses and is compared to a baseline planar endwall. The blade inlet span increased by 13 degrees with respect to the inlet in order to match engine representative inlet/exit Mach number loading in a HP turbine. The experiments were performed in a quasi-2D linear cascade with measurements at design exit Mach number 0.88 and incidence angle. Four cases were analyzed for each endwall -- the effect of slot presence (with/without coolant) and the effect of discrete holes (with/without coolant) without slot injection. The coolant to mainstream mass flow ratio was set at 1.0% and 0.25% for upstream purge slot and discrete holes, respectively. Aerodynamic loss coefficient is calculated with the measured exit total pressure at 0.1 Cax downstream of the blade trailing edge. CFD studies were conducted in compliment. The aero-optimized endwall yielded lower losses than baseline without the presence of the slot. However, in presence of the slot, losses increased due to formation of additional vortices. For both endwall geometries, results reveal that the slot has increased losses, while the addition of coolant further influences secondary flow development. / Master of Science
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Synthesis of redox units and modification of mesoporous surfaces by covalent cascade reactionsAsaftei, Carmen Simona 01 September 2005 (has links)
In dieser Arbeit wird ein neuer Ansatz beschrieben, elektroaktive Verbindungen auf mesoporösen Elektroden zu fixieren. Dies wurde durch die Bildung eines sich selbst organisierenden Monolayers auf der Innenseite eines mesoporösen Trägers (ITO, FTO, ATO, TiO2) erreicht. Dieser Layer wurde dann vernetzt und in Richtung des Porenzentrums weiter aufgebaut durch Substitutions- Kondensations- oder Elektropolymerisations- Reaktionen. Es wurde ein Vernetzungsverfahren entwickelt, welches die Herstellung stabiler elektrochromer Bilder mit verbessertem Kontrast und einer Haltbarkeit von mehr als 18 Monaten erlaubt. Es beinhaltet die Synthesen von molekularen Einheiten mit latent vorhandenen oder voll entwickelten elektrochromen Eigenschaften. Diese Einheiten waren 4,4´- Bipyridine, die entweder mit optionalen N-Alkyl, N-Benzyl oder N-Phenyl Gruppen mit nukleophilem oder elektrophilen Eigenschaften oder mit TiO2 Ankergruppen versehen waren. Die Kaskadenreaktion ergab Elektroden mit unterschiedlichen Oberflächenkonzentrationen und unterschiedlichen Pimerisationsgraden. Darüber hinaus gelang es, die Haltbarkeit und den Kontrast so weit zu steigern, dass sie kommerziellen Ansprüchen genügen. Die Optimierung der Gegenelektroden wurde durch ein ähnliches Verfahren unter Verwendung von Ferrocen- Derivaten erreicht. Die Ladungskapazitäten, die durch Multilayer Vernetzung auf ATO-Ferrocen Elektroden erhalten wurden, waren hervorragend mit Ausnahme der Tatsache dass ein schwach grüner Farbton, verursacht durch oxidiertes Ferrocen, vorhanden war. Schließlich wurde die Kaskadenreaktion auf B12 Derivate zur Herstellung von katalytisch aktiven TiO2 Elektroden angewandt. Die mit B12 modifizierten Elektroden zeigten verbesserte Stabilität, höhere turn over - Zahlen und größere turn over -Raten im Vergleich zu unvernetzten B12 modifizierten Elektroden.
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Precision Current Control for Quantum Cascade Lasers as Flight Calibration SourcesHansen, Stewart M. 01 May 2014 (has links)
The design of a precision current controller for quantum cascade lasers (QCLs) enables QCLs to be used for calibrating instruments in space-borne applications. This current controller design will enable constant wave (CW) or pulsed mode operation of QCL devices as calibration sources in a space environment. Any differences in the temperature between components of the current controller can result in an erroneous current through the QCL. This design will use previously demonstrated techniques from Pacific Northwest National Laboratory (PNNL) to minimize the effects of temperature changes on the desired current levels. A mathematical model is used to calculate what performance levels can be expected, and if the board can operate with a desired precision level of 0.1% of the desired power output of the QCL. This mathematical model shows the capability to control to the desired 0.1% output power stability with a change in the boards temperature of ±10◦C.
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Mid-infrared InGaAs/InAlAs Quantum Cascade Lasers / 中赤外InGaAs/InAlAs量子カスケードレーザに関する研究Fujita, Kazuue 24 September 2014 (has links)
京都大学 / 0048 / 新制・論文博士 / 博士(工学) / 乙第12860号 / 論工博第4107号 / 新制||工||1609(附属図書館) / 31540 / (主査)教授 北野 正雄, 教授 川上 養一, 准教授 酒井 道 / 学位規則第4条第2項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
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Synthesis of Fused-Ring Compounds through Gold-Catalyzed Cascade Reactions / 金触媒連続反応を用いた縮環型化合物の合成研究Naoe, Saori 23 March 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(薬科学) / 甲第19669号 / 薬科博第57号 / 新制||薬科||7(附属図書館) / 32705 / 京都大学大学院薬学研究科医薬創成情報科学専攻 / (主査)教授 大野 浩章, 教授 高須 清誠, 教授 竹本 佳司 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM
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Exploring the Effectiveness of the Urban Growth Boundaries in USA using the Multifractal Analysis of the Road Intersection Points, A Case Study of Portland, OregonSaeedimoghaddam, Mahmoud 22 October 2020 (has links)
No description available.
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Cable path optimization methods with cascade structures for industrial robot arms using physical simulators / 物理シミュレータを活用した産業用ロボットアームのためのカスケード構造を有するケーブル経路最適化手法に関する研究Iwamura, Shintaro 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(工学) / 甲第24606号 / 工博第5112号 / 新制||工||1978(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 松野 文俊, 教授 松原 厚, 教授 泉井 一浩 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM
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An Investigation of Gold(I) Catalyzed Cycloaddition ReactionsConyers, Ryan C. 19 April 2013 (has links)
No description available.
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Model Studies Towards the Total Synthesis of Lyconadin A via An Acyl Radical Cascade ReactionZhu, Koudi 30 June 2006 (has links) (PDF)
Lyconadin A is an alkaloid possessing a unique structure and antitumor activity. The total synthesis of Lyconadin A was proposed via an acyl radical cascade reaction. To investigate the possibility and stereoselectivity of the cascade cyclization, phenyl selenoester 16 was chosen as a model substrate to study the 7-exo-5-exo radical cyclization. A synthetic route to phenyl selenoester 16 was developed. The 7-exo-5-exo radical cyclization was found to occur with a high yield and excellent stereoselectivty. Attempts were also tried to synthesize another radical precursor 14 albeit with less success. A synthetic pathway to the synthesis of 14 as well as its potential use in the context of the synthesis of Lyconadin A was proposed.
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