In this study, we establish a car body PEC model by using a NEC-2-based numerical software. Based on this model, we then carry out a series of simulations and analysis in the FM band concerning the effects of various car structures on antenna patterns. The results have been compared with those available in open literature in order to verify our model. The simulation results show that the roof support pillars significantly affect the antenna patterns. We investigate the ripples caused by the finite ground plane in the antenna patterns, and propose a new edge treatment technique. Our results indicate that a significant reduction of these unwanted ripples can be obtained, if the proposed technique is applied. The effect of car glasses and human body is also taken into consideration. At last, the issue of studying the effects at higher frequencies is addressed. Two approaches are used, including UTD, and PO. Satisfactory results are obtained.

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Quantum well infrared photodetectors (QWIP) utilize quantum wells of large bandgap materials to detect infrared radiation. When compared to conventional low bandgap LWIR photodetectors, the QWIP technology offers largest format thermal imagers with much better uniformity. The theoretical part of this study includes the development of a QWIP ensemble Monte-Carlo simulator. Capture paths of electrons to quantum wells are simulated in detail. For standard AlGaAs/GaAs QWIPs, at medium and high E-fields L valley quantum well (QW) is a trap for electrons which causes higher capture probability when compared with InP/InGaAs and GaAs/InGaAs QWIPs. The results suggest that high photoconductive gain observed in InP/InGaAs and GaAs/InGaAs QWIPs is not due to good transport properties of binary barrier material but due to higher &amp / #61511 / -L valley energy separation. The experimental part of the study includes the fabrication and characterization of InP/InGaAs and InP/InGaAsP QWIPs and 640x512 FPAs with the main objective of investigating the feasibility of these material systems for QWIPs. The InP/InGaAs and InP/InGaAsP QWIP detectors showed specific detectivity values above 1010 cm.Hz1/2/W (70K, f/2, background limited). The devices offer higher allowable system noise floor when compared with the standard AlGaAs/GaAs QWIP technology. It is also experimentally shown that for strategic applications LWIR InP based QWIPs have advantages over the standard QWIP technology. The InP/InGaAs 640x512 QWIP FPA reached 36 mK average NETD value at 70 K with f/1.5 optics and 10 ms integration time. The InP/InGaAsP QWIP on the other hand yielded 38 mK NETD histogram peak at 70 K with f/1.5 optics and 5 ms integration time on 320x256 window of the 640x512 FPA.

The main aim of this study is to extending the holographic interferometry technique to measure the out-of-plane displacement of an object subjected to both temperature and displacement field. It is noted that both the out-of-plane displacement and the ambient temperature change can cause image fringes. Therefore, an auxiliary object is used to identify the fringe numbers caused by the ambient temperature change during the experiment. The warpage measurement of a PBGA package is used as an example. It can be shown that the proposed method works

In the present study, the buckling behavior of beams is analyzed by a plane strain finite element. The displacement-type finite element formulation is based on elasticity and has no any other simplification and assumption except that the beam is of moderate depth. Also all the displacement boundary conditions can be imposed exactly. These are the advantages that beam theories of conventional approach, which simulate beams with neutral plane behaviors, do not have. Therefore the present analyses should be able to obtain buckling load and buckling mode more accurately than conventional method. Numerical values of buckling loads of the present approach will be compared with previously published results of the Euler-Bernoulli beam theory and the Timoshenko beam theory, and further with the high order beam theory to reveal their differences. The effects of the geometry ratio, the distribution of axial loads and the displacement boundary conditions on buckling of beams are also discussed.

Taiwan is the major country of importing LNG. In this paper discussed LNG cold energy recovery used in cold storage warehouse and other energy conservation systems. In the cold storage warehouse systems that showed the less temperature of cold storage warehouse the more exergy efficiency and the best exergy efficiency is 30%. Base on thermoeconomic analysis there was the optimal operation temperature at -70¢J. In the purifier nitrogen system (PNS), the investigation indicated the best efficient operating temperature at -150¢J. But with economic analysis the optimal design temperature of this PNS was -130¢J. And the last energy conservation system was the running power plane. In this research studied the power planes used LNG cold energy as inlet air-cooling systems. According to the investigation that showed the systems increased power output up to 14.4¢H in the 4.5¢J of inlet air cooling temperature. And these systems also improved the heat rate of power planes about 0.98%. The conclusions presented that the potentialities of LNG cold energy are huge, and with proper engineering and economic analysis could make these energy conservation systems more feasible.

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This thesis will talk about the difference between c-plane and m-plane GaN. We use C-V measurement and try to find the difference from C-V result. We use atomic layer deposit (ALD) to deposit Al2O3 no n-Si (111), p-Si (111), c-GaN, m-GaN, c-InN and m-InN for making MOS structure. And use 100 kHz to measure high frequency C-V and charge-voltage method to measure quasi-static capacitance and leakage current. The process and how the instrument work will present in article. In Si (111) case, the flat-band voltage is far away from ideal value. This tells us charge in oxide. Result of quasi-static method shows interface state density is between 1011 cm-2¡DeV-1 to 1012 cm-2¡DeV-1. From Ref. 13, SiO2-Si system with 1011 cm-2 interface trap charge density for Si (111). We compare C-V carrier concentration with Hall carrier concentration and find some difference. We put C-V result of experiment and simulated with COX and Hall carrier concentration we measured. In GaN case, here is deep depletion in C-V result. And quasi-static result also shows deep depletion of GaN. This phenomenon means generate time of hole of n-type GaN is very long. And we use light to excite electron and hole and measure C-V for average surface density of state. The density of stay of Al2O3/m-GaN and Al2O3/c-GaN system is similar. Only appearance difference between Al2O3/m-GaN and Al2O3/c-GaN is position of flat-ban voltage. flat-ban voltage of c-GaN is more negative than m-GaN. For InN, we see ¡§the middle is lower than edge¡¨ curve. Recently, few group present complete C-V curve of InN. We can not sure whether we can use typical way to analyze this data.

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