Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 34 for “"efficiency enhancement"”.
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Efficiency enhancement techniques for RF and millimeter wave power amplifiers
… of techniques that can be used to improve the efficiency of power amplifiers and break the power-frequency tradeoff in power amplifier design. The first technique emphasizes the use of a class E tuned output network as an efficiency enhancement tool for power amplifiers regardless of their bias …
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Efficiency Enhancement of Base Station Power Amplifiers Using Doherty Technique
… is achievable, it always comes at the expense of efficiency. Most of the modern wireless applications such as WCDMA use non-constant envelope modulation techniques with a high peak to average ratio. Linearity being a critical issue, power amplifiers implemented in such applications are forced to …
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Efficiency droop mitigation and quantum efficiency enhancement for nitride Light-Emitting Diodes
… state-of-the art InGaN-based LEDs, including ‘efficiency droop’ issues that cause output power quenching at high current injection levels (> 100 A/cm2). In this dissertation, approaches were investigated to address the major issues related to state-of-the-art nitride LEDs, in particular related …
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Efficiency enhancement and degradation processes in CuxS/CdS thin film solar cells
… improvements in the photovoltaic conversion efficiency were shown to be possible as a result of such treatment.The rate of degradation of cells exposed to air was also found to be dependent on the previous history of the cell. An increased concentration of Cd in the CuxS film (due to …
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Power system analysis criteria-based computational efficiency enhancement for power flow and transient stability
Made available in DSpace on 2014-09-16T17:25:26Z (GMT). No. of bitstreams: 3 Soobae_Kim.pdf: 1313745 bytes, checksum: 0e6d8a9709a7222ca3471ebd545cb314 (MD5) Kim_Soobae.tex: 136779 bytes, checksum: 931c9b852258f804300a3ebc5fd336bb (MD5) license.txt: 4058 bytes, checksum: …
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Analysis of Light Extraction Efficiency Enhancement for Deep Ultraviolet and Visible Light-Emitting Diodes with III-Nitride Micro-Domes
… The limitation occurred in light extraction efficiency of III-nitride LEDs is attributed to the large refractive index difference between III-nitride semiconductor and free space, which leads to significant total internal reflection at the semiconductor and air interface. This thesis presents …
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High efficiency thin film silicon solar cells with novel light trapping : principle, design and processing
One major efficiency limiting factor in thin film solar cells is weak absorption of long wavelength photons due to the limited optical path length imposed by the thin film thickness. This is especially severe in Si because of its indirect bandgap. This thesis invents a novel light trapping scheme, …
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An Optimization of Thermodynamic Efficiency vs. Capacity for Communications Systems
… view of the mechanisms which affect the power efficiency of communications processes along with a method for efficiency enhancement. Shannon's work is the definitive source for analyzing information capacity of a communications system but his formulation does not predict an efficiency …
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Photon Generation and Dissipation in Organic Light-Emitting Diodes
… fluorescence emitters, the internal quantum efficiency of organic light-emitting diodes (OLEDs) can now reach 100%. However, a major fraction of generated photons is trapped inside the device, because of the intrinsic multi-layer device structure and the mismatch of refractive indices. This …
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Design and Linearization of Energy Efficiency Power Amplifier in Nonlinear OFDM Transmitter for LTE-5G Applications. Simulation and measurements of energy efficiency power amplifier in the presence of nonlinear OFDM transmitter system and digital predistortion based on Hammerstein-Wiener method
… amplifiers (RFPAs) that address initiatives for efficiency enhancement and linearity compensation to harmonize the fifth generation (5G) campaign. The objective is to enhance the performance of an orthogonal frequency division multiplexing-long term evolution (OFDM-LTE) transmitter by reducing …
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Development And Characterization Of Beamforming Antenna Systems
… beam-splitting with FSS (chapter 5). Lastly, efficiency enhancement of the FPC antenna system using FSS subarray is studied.
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"Quality" in urban management
… industrial economies, was seen as a tool of efficiency enhancement in the production of goods. Quality Assurance and Management concepts are now firmly entrenched in the corporate approach to the more efficient production of both goods and services. Herein lies the justification for the line …
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Amplifier Architectures for Wireless Communication Systems
… amplifiers. On the transmitter side, enhanced efficiency and broader bandwidth over single and multiple bands on power amplifiers will help to have superior performance in communication systems. On the other hand, for the receiver side, having low noise and high gain will be necessary to ensure …
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Linear Power-Efficient RF Amplifier with Partial Positive Feedback
… gain conditions, resulting in poor power efficiency. Various efficiency-enhancement solutions have been realized for backed-off devices to combat this issue.</p> <p>A brief overview of one of the more extensively researched solutions, the Doherty amplifier, is given, and its inherent …
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A novel design methodology for enhanced compressor performance based on a dynamic stability metric
… such that any combination of pressure ratio, efficiency and dynamic stability can be prescribed at various operating speeds. The compressor design optimization framework uses an effective blade-to-blade CFD method (fast blade performance prediction method) to predict the blade row performance …
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Novel photonic phenomena in nanostructured material systems with applications and mid-range efficient insensitive wireless energy-transfer
… two 60cm-diameter resonant objects and with 45% efficiency. A technique for further efficiency enhancement and radiation suppression is suggested, based on employing destructive interference between the coupled-objects' radiated far-fields. The scheme is also found fairly insensitive to the …
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Common Energy Saving Programs in Residential Buildings Operation: A Survey and Analysis of Existing Studies
… the residential sector, including energy efficiency enhancement, fuel switching, energy supply decarbonization, and behavioral energy efficiency (BEE) programs. This thesis elaborates on the empirically approved behavioral science principles that make effective the various types of BEE …
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Enhancing solar cells with plasmonic nanovoids
… the use of plasmonic nanovoids for enhancing the efficiency of thin-film solar cells. Devices are fabricated inside plasmonically resonant nanostructures, demonstrating a new class of plasmonic photovoltaics. Novel cell geometries are developed for both organic and amorphous silicon solar cell …
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Quantum dot gain-lever laser diode
… lasers such as enhancing the modulation efficiency and improving the overall modulation bandwidth. The gain lever effect is a method used to enhance the efficiency of amplitude modulation and optical frequency modulation at microwave frequencies by taking advantage of the sub-linear …
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Modeling and Scheduling for Sensor Network Quality-of-Experience Enhancement
… sensor applications. We define it as the energy efficiency enhancement provided by a system to prolong the operational lifetime of a sensor network. This dissertation addresses the important and challenging problem of enhancing sensor network QoE. Quality-of-experience is characterized as, …
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