Modeling of electromagnetic wave propagation in terms of Gaussian beams (GBs) has been considered in recent years. The incident radiation is expanded in terms of GBs by means of the point matching method. The simultaneous equations can be solved directly to produce excitation coefficients that generate the approximate pattern of a known antenna. Two different types of antenna patterns have been approximated in terms of GBs: a truncated antenna pattern and a hyperbolic antenna pattern. The influence of the Gaussian beam parameters on the approximation process is clarified.

A database of composite column tests was augmented and utilized to evaluate the proposed AISC 2005 provisions. The database consists of column and beam-column steel-concrete columns (or encased, SRC), circular concrete filled tubes (CCFT), and rectangular concrete filled tube (RCFT). Information on material and geometric properties on each specimen was summarized. The database includes 119 SRC columns, 136 SRC beam-columns, 312 circular CFT columns, 198 circular CFT beam-columns, 222 rectangular CFT columns and 194 rectangular CFT beam-columns. The database has a total of 1181 specimens, an addition of 451 specimens over those in the original database (Aho 1996). The data on each specimen was analyzed and compared with current design provision for composite columns (AISC 1999 and Eurocode 4), and reassessed by the upcoming 2005 AISC specification. The data indicates that the Eurocode gives good predictions for columns and the AISC 2005 method performs very well for beam-columns. For rectangular CFT columns, all three methods predict the ultimate capacity very well. The main improvement for the AISC 2005 method is its ability to handle specimens which have high yield stress and/or high strength concrete.

The purposes of this thesis are to prepare ZnO and tin-doped In2O3 (ITO) films at low temperature and study their microstructure and optoelectronic properties. Low-temperature growth of undoped ZnO films with high transparency and low electrical resistance was prepared by ion beam sputtering. After systematic testing, a sheet resistivity as low as 2.95 x 10-3 £[-cm was obtained at a substrate temperature of 150 oC, ion source voltage of 850 V, and ion beam current of 30 mA. The transmittance of the ZnO films was in the range of 85-90%. Hall measurements showed that a high mobility of 21.41 cm2/Vs was obtained for films less than 200 nm thick. The related microstructures and physical properties were measured and discussed. ZnO nanofilm of (2-1-10) and (01-11) surfaces were prepared on NaCl (001) surface at 200 oC and 400 oC to produce nearly pure (2-1-10) and (01-11) textures respectively and the orientation relationships were determined and the interface discussed. By dissolving the NaCl substrate, the ZnO (2-1-10) and (01-11) surfaces several cm2 in area, which may have some useful applications, can be easily prepared. The photoluminescence spectrum from the (2-1-10) surface showed only a near-band-edge UV emission peak while the (01-11) surface showed a near band-edge UV emission and a broad green emission. Low-temperature preparation of transparent conducting electrode is essential for flexible optoelectronic devices. ITO films of high transparency and low electrical resistance were prepared at room temperature with a radio-frequency ion beam sputtering system. Specimens with a low sheet resistivity of 10-4 £[-cm and a high visible-light transmittance of 85-90% were obtained. Hall measurement was used to measure the mobility and carrier concentrations and the effects on resistivity were discussed. ITO films were deposited on glass substrates at 200 oC at various oxygen flow rates. At low oxygen flow rate the film surface has ITO whiskers with metallic In tips and a crystallographic relationship of (010)In//(110)ITO and (001)In//(001)ITO is present between them. The In tips act as the seeds for the growth of ITO whiskers by a vapor-liquid-solid growth mechanism. As the oxygen flow rate increases, the crystallinity of the ITO film decreases till an amorphous phase is formed. The microstructure, resistivity and transmittance of the films were studied as a function of oxygen flow rate. Thin films of high transmittance (~90%) and low resistivity (6 x 10-4 Ω-cm) were prepared at an intermediate oxygen flow rates.

This study aims to analysis the seasonal fluctuation fisheries assemblages and fishing yield by weight and amount of per unit effort using commercial shrimp beam trawlers at the waters off Yunlin, southwestern Taiwan during 1997-2007. In total, 47 sampling cruises, 320 taxa belonging to 205 genera and 102 families were identified. Among these, twelve species occurred greater than 80%. The species number of teleost fish were the most in each sampling. The total fish yield were 3032.9 kg and 304,680 individuals in the sampling period. Shrimps, the target species of the commercial beam trawler, were collected 945.7kg (31.2% of the total fish yield) and 181,050 individuals (59.4% of the total fish yield) , both are the most dominant fish yield among the fishing communities. The teleost fish (865.2 kg, 31.2%) and snails (73,868 individuals, 24.2%) were with the most fish yield in terms of weight and amount, respectively. The dominant species presented a seasonal pattern with a highly oscillation yield in both weight and biomass of the species in the same season each year. Thirteen species were recognized as the mainly harvested animals in of seasonal the commercial shrimp beam trawler. This study also showed that the shrimp, Parapenaeopsis hardiwckii, from February to May, and the portunid crab, Portunus sanguinolentus, from August to November in each year had the most production by cluster analysis. Since, the coastal zone at Yunlin were selected for constructing as an industrial park from May, 1998. Therefore in related to the development of the industrial park, to compare the production of 13 mainly harvest animals individually between three industrial developmental stages (pre-development: 1997.1-1998.2, development: 1998.5-2004.12 and post-development: 2005.2-2007.12). The results showed that the production of 3 species, Tanea lineate, Glossaulax didyma and Parapenaeopsis hardiwckii, decreased significantly (p< 0.05), where as of 2 fish species, Arius maculates and Chrysochir aureus, increased. By in large the other species was not remained the same after the construction.

The thesis focuses on the study of asymmetric multiple quantum wells(AMQWs) grown by molecular beam epitaxy (MBE) in the Riber Compact 21T MBE system. We investigate AMQW structures in which the well width is varied but the material compositions of the wells and the barriers are kept constant. Also, we have investigated AMQWs with p-type modulation doping at the barrier region and the AMQWs of different well widths without changing the well compositions. The AMQW samples are obtained the emission spectra by using photoluminescence (PL), electroluminescence (EL), photo-current and photoreflectance (PR) in the experiments. Also, The AMQW samples (AMQ100-70-40 and AMQ-100-MD70-40) are fabricated into laser diodes to obtain the characteristics of device in this study. The threshold current density Jth of laser diode is measured about 2 kA/cm2.The internal quantum efficiency £bi and the absorption £\ of AMQ-100-70-40 are 34.7% and 9.47 cm-1 respectively. The internal quantum efficiency £bi and the absorption £\ of AMQ-100-MD70-40 are 22.2% and 10.56 cm-1 respectively. Moreover, we present the InGaAsP AMQW samples grown by MOCVD to compare with the InGaAs/InAlGaAs AMQW samples. The broad-band property is valuable for application of optical communication. It is highly desirable to have broadly tunable lasers and broad-band semiconductor optical amplifiers (SOAs) in the 1.3 or 1.55£gm to handle more number of channels increasing the volume of information traffic for future optical communication networks. The band-band light source is also desirable in medical science for the optical coherence tomography (OCT).

Both non-polar (10-10) (m-plane) and polar (0001) (c-plane) zinc oxide (ZnO) have a good lattice match with lithium aluminum (LiAlO2, LAO) (200) substrate, so it is difficult to control the epitaxial orientation. Therefore, this research is to explore how the growth parameters influence on the crystal orientation of ZnO film grown by plasma assisted molecular beam epitaxy. The experimental results show that m-plane ZnO can be grown with low zinc flux and low oxygen pressure. Increasing zinc flux and oxygen pressure will lead to increase in growth rate, and consequently, c-plane ZnO will nucleate on the substrate besides m-plane zinc oxide. The substrate temperature is one of the main factors that influence the choice of zinc oxide epitaxial orientation. High temperature will promote the m-plane zinc oxide nucleation, while low temperature will conduct to the c-plane zinc oxide nucleation. Under low zinc flux and low oxygen pressure, epitaxy of ZnO with different crystalline orientations can be achieved through changing the substrate temperature. The surface morphology and roughness of the substrate will affect the particle size and surface morphology of ZnO epilayers. When the substrate is smooth, the crystal size of the epitaxial film is large and the surface is flat with many rectangular stripes, taking on the platform-like morphology. If the substrate is rough with many scratches, the particle size becomes small and the surface is granular-like and rather rough. Furthermore, when the substrate is rough, it is difficult to control the different orientations of ZnO epitaxial films through changing the substrate temperature.

A polarization-independent electro-optically tunable add/drop filter utilizing non-polarizing novel relaxed beam splitters has been developed in LiNbO3 at the 1.55μm wavelength regime. The operation of this filter is based on passive directional coupler type beam splitters and strain-induced phase-matched TE↔TM polarization mode converters on an asymmetric Mach-Zehnder interferometer waveguide configuration. Fabrication parameters for channel waveguides, relaxed beam splitters and polarization mode converters were optimized individually then integrated to produce the final device. Single mode channel waveguides for both TE and TM polarizations were realized by the diffusion of 7μm wide Ti strips into LiNbO3 substrate. Relaxed beam splitters were produced using Ti diffused waveguides in a directional coupler configuration with 3.5mm long coupling region, 0.6º bending angle, and separation gap of 11μm and 13μm between waveguides. Tunable TE↔TM polarization mode converters with 99.8%

The main work of this thesis is to design the TE-polarized SOA structures for booster amplifier, and the polarization-independent SOA structures for preamplifier at receiver end. In the SOA structure, we add a lattice-matched ternary compound InGaAs as an extra quantum well in separate-confinement heterostructure (SCH) layer. The purpose is to result in the band-filling/shrinkage and lead to change the absorption coefficient. Therefore, the refractive index change will be increased, and the structure can work as a Mach-Zehnder interferometer under reverse bias. We also added an electron barrier InAlAs layer to reduce the carriers accumulation in the extra InGaAs QW. After the epitaxy of MOCVD, this designed structure was processed to be a ridge laser. From the measurements of ridge laser, the barrier InAlAs could not efficiently stop the carrier injection into the extra InGaAs QW. The other part of this thesis is to set up a digital signal apparatus to analyze the RHEED pattern on the screen of the chamber. We make a connection between CCD camera and PC utilizing the framegrabber in RHEED system, and develop the programs from LabVIEW and IMAQ to obtain the functions we need. Further, from the tests of grabing and analysis for RHEED pattern, the digital signal system on RHEED pattern has been successfully demonstrated.

The thesis consists of two aspects: (1) Research on regrowth by molecular beam epitaxy, and (2) Silicon monoxide coating. In part one, we used (NH4)2Sx to passivate the InAlGaAs/InP surface. From the X-ray photoelectron spectroscopy (XPS), the passivated surface shows a dramatic reduce of oxidation. A preparation chamber for the regrowth has been setup to proceed the sulfur passivation method. We can obtain a clean surface for regrowth after heating and putting samples in the high vacuum chamber. In the design of regrowth layers, we have found the best waveguide structure by regrowth. When the ridge width is 2.5 mm with etching depth 1.4 mm, a circular mode profile can be obtained by Fimmwave simulation. In the integration between devices, we have designed the best waveguide structure after regrowth by BeamProp 3D. The best design will make the propagation loss smaller than 0.21%. The second part is anti-reflection (AR) coating by silicon monoxide (SiO) deposition. The SiO refractive index of 1.8837 was obtained by transmission, and ellipsometer measurements. The corresponding AR coating thickness for InP substrate is 2057 &#x00C5;. In order to make AR coating on lasers of different effective index, we design the double-layer coating. For Beam Expander Semiconductor Optical Amplifier (BESOA), SiO2 / SiO and Si3NX / SiO double-layer coatings were compared with SiO single layer. The reflectance (R) was reduced 16.86 % and 25.12 %, respectively, and the R < 1% bandwidth extends 200 &#x00C5;.

Nanocrystalline £\-Zr condensates deposited by ion beam sputtering on the NaCl (100) surfaces and then annealed at 100 oC to 750 oC in air. The phases present were identified by transmission electron microscopy to be nanometer-size £\-Zr+ZrO¡B£\-Zr+ZrO+c-ZrO2¡Bc-ZrO2¡Bc-+t-ZrO2¡Bt-ZrO2¡Band t-+m-ZrO2 phase assemblages with increasing annealing temperature. The zirconia showed strong {100} preferred orientation due to parallel epitaxy with NaCl (100) when annealed between 150 oC and 500 oC in air. The c- and t-zirconia condensates also showed (111)-specific coalescence among themselves. The c- and/or t-ZrO2 formation can be accounted for by the small grain size, the presence of low-valence Zr cation and the lateral constraint of the neighboring grains.