In this study, epitaxial ZnO films were grown by chemical vapor deposition (CVD) on LSAT(100) substrate. A high-quality [100] (La0.3,Sr0.7)(Al0.65,Ta0.35)O3 (LSAT) single crystal with the diameter of 60mm was grown by Czochralski pulling technique in our lab. Epi-ready LSAT substrates with rms roughness of 0.30nm ~ 0.35nm were used for all of the experiments. Nonpolar ZnO with [11-20] orientation (a-plane) was directly grown on a (100) LSAT substrate without any buffer layer by chemical vapor deposition (CVD) method. (100) LSAT single crystal substrate is loaded in a 2¡¨ quartz tube inserted to a two-temperature zone furnace. Zinc acetylacetonate hydrate (Zn(C5H7O2)2¡DxH2O, Lancaster) source was vaporized at the lower temperature of 130~140oC. The vapor was carried by a mixture of N2/O2 gas flow into the high temperature zone where the (100) LSAT substrate was located. At first, the pressure of the quartz chamber was pumped to 8¡Ñ10-3 Torr, and then kept at 150 ~ 250 Torr. The flows rates of both O2 and N2 are 500sccm. During the growth, the temperature was varied from 700 to 780oC. The growth conditions were controlled by adjusting the growth temperatures and chamber¡¦s pressures. The overall reaction was: Zn(C5H7O2)2 +12O2¡÷ZnO+ 10CO2 +7H2O Scanning electron microscope [(SEM), JEOL JSM-6330TF)] is used to examine the different surface morphologies of ZnO epitaxial film. The orientation and structure were investigated by X-ray diffraction pattern (XRD) using a Siemens D5000 X-ray diffractometer with a Cu anode at 40 kV and 30 mA. The wavelength of X-ray radiated from the Cu K£\1 is 0.1540 nm. The X-ray scan step is 0.01¢X. A JEOL 3010 scanning transmission electron microscope (STEM) operated at 200kV was employed to characterize the microstructures and orientation of the nonpolar ZnO film. Cross-sectioned TEM samples were prepared using the focus ion beam lift-out method. A Pt layer of about 8nm in thickness was pre-deposited on the sample to prevent charging. Room temperature photoluminescence (RT-PL) measurements were performed using a 325nm He-Cd laser. The emitted light was detected by a Jobin-Yvon TRIAX 550 monochromator with 0.025nm resolution.

In this thesis, we will try to grow m-plane InGaN blue light-emitting diodes (LEDs) and discuss the characteristics. First, pure m-plane GaN on the m-sapphire grown by plasma assisted molecular beam epitaxy (PAMBE) had been achieved. ¢½/¢» ratio and the growth temperature are the most important factors in the growth sequence. M-GaN film with better crystal quality was grown successfully by tuning these two factors. Indium composition in the InGaN layer is an important issue in the growth of blue LEDs; In/Ga ratio could affect the bandgap i.e. the target wavelength of a LED. We have to regard the crystal quality and the target wavelength of the InGaN layer in growth procedure. Structural properties were investigated by X-ray diffraction (XRD). XRD measurements showed that the crystal orientation of GaN films was pure m-plane. From cathodoluminescence (CL) spectra, the luminescence wavelength of InGaN layer is in the blue-light range. The crysatalline of m-plane InGaN blue LEDs were analyzed by XRD and Electron Back-Scattered Diffraction (EBSD). Electroluminescence (EL) was measured under the different inject current conditions; the polarization of EL was also measured. Moreover, the current-voltage curve and current-output curve were carried out.

The paper extends the analytical results obtained by Hwung et al. (1981) and further considers the non-linearity of waves to investigate variation horizontal velocity, temperature distribution induced by interaction of 2-D plane jet and waves. On the steady state, the nonlinear wave is considered as external force in motion equations, the property of momentum conservation of jet flow, and radiation stress are applied to analyze the interaction of waves- jet flow in arbitrary profile. The scale function 1 £` £\1(x) , 2 2£` £\ (x) between the variation function f (x,y) and velocity distribution can also be obtained. The non-dimensional theoretical solution is also useful to estimate the relative characteristics in the physical field. The momentum equation and velocity distribution of interaction without property of temperature diffusion are employed to find the temperature distribution for arbitrary sections. Based on the experiments and theory solution obtained by Hwung et al. (1981) it is found that time-averaged horizontal velocity and temperature are Gaussian distribution, the coefficient of horizontal velocity 1 c , and temperature distribution 2 c are 0.105, 0.148, respectively. In the present, two coefficients considered as non-linearity of waves 1 c = 0.124 and 2 c = 0.152 are determined. In other words, it is shown that exact solution and boundary effect included non-linearity of waves is related to velocity of jet flow, wave periods, relative depth and steepness of waves respectively. Comparing with experiments indicated that the analytical solution of the present for MSE is well confirm the experimental results and better than linear results obtained by Hwung et al. (1981) The influence due to interaction of 2-D turbulent jet flow and Stokes waves can be obtained by using dimension analysis. Moreover, the related properties inside the flow also can be estimated.

Multibeam sonar systems are much more efficient than the convectional single-beam echo sounders for seafloor-mapping in hydrographic surveying. On the other hand, the operation of multibeam sonar systems needs to integrate more auxiliary sensor units. Because the world coordinates of each footprint is calculated based on the geometry of the sonar head relative to the GPS of the ship. Therefore, the resulting survey quality highly depends on the accuracy of the estimated mounting configuration of the sonar head, and other sensor units. Basically, the configuration parameters include the three Euler's angles, three linear translations and the asynchronous latency of signals between the transducer and other sensors. These parameters can not be measured directly. They can only be estimated from the post-process of the bathymetry data called patch test. Generally, the patch test requires the survey ship to follow several designated paths which are parallel, reciprocal or perpendicular to each other. Furthermore, the choice of seabed slope is also an important factor for the quality of the result. The contour plots of the seabed for the different paths are used to estimate the mounting configuration of the sonar head. In this work, we propose best-fitting a small flat patch to represent the seabed right beneath a segment of the path. A pair of patches from the two adjacent segments of reciprocal or perpendicular paths are selected for comparison. The difference between the two patches gives us an idea how the mounting parameters, i.e. the rolling, pitching and yawing angles, might be. If the parameters are accurately estimated, the two patches should be co-plane. We design several semi-positive definite functions and feed back control algorithms to steer the mounting angles to search for the solutions. One more advantage of this approach is that the variation of each mounting angles as the survey undergoes can be monitored. We test this idea with simulated seabed data, and field data as well. The result is within 1\% difference compared with respect to the angles calibrated by commercial software, such as Hypack.

Thesis (doctoral)--Vereinigte Friedrichs-Universität Halle-Wittenberg, 1913. / Cover title. Vita.

Thesis (Ph. D.)--Columbia University, 1931. / Vita.

Thesis--Universiteit te Utricht, 1937. / "Literatur": p. 93-95.

No description available.

Thesis--Universiteit te Utricht, 1937. / "Literatur": p. 93-95.

Diss.--Breslau (H. Dittrich, A. Koch, and M. Jacobi, respondents). / Title vignette.