Study on mechanical properties of GaN epitaxy films grown on sapphire by MOCVD

GaN epitaxy films were grown on (0001) oriented sapphire substrate by metal-organic vapor deposition(MOCVD). AFM and SEM were used to analyze the surface morphology of GaN films. Hardness and critical load of GaN films were measured by an nano-indentation tester, friction coefficient by reciprocating UMT-2MT tribometer. It is found that the surface of GaN film is smooth and the epitaxial growth mechanism is in two-dimension mode, GaN epitaxy films also belong to ultra-hardness materials, whose hardness is 22.1 MPa and elastic modulus is 299.5 GPa. Adhesion strength of epitaxial GaN to sapphire is high, and critical load reaches 1.6 N. Friction coefficient against GCr15 ball is steadily close to 0.13, while GaN films turns to be broken rapidly by using Si3N4 ceramic ball as counterpart.

Comparison of Loss and Crosstalk Characteristics of SOI Based Intersecting Waveguides with Different Bend Structures

By means of two dimension beam propagation method (2D-BPM) with high order Pade approximation, behaviors of SOI waveguide based bend intersections with variant bending radius are simulated and analized. The result shows that crosstalk of intersections decreases with the increase of bending radius and intersecting angle. Furthermore, loss and crosstalk characteristics of bend intersections formed by sine bend, cosine bend and arc bend are compared. Sine bend based structures are proved that it can present lowest loss and smallest crosstalk properties among the three and may find their wide application in the design of bend intersections and other more complicated photonic devices and circuits.

Elastic Strain Field Distribution of a Self-Organized Growth Lensed-Shaped Quantum Dot by Finite Element Method

The stress and strain fields in self-organized growth coherent quantum dots (QD) structures are investigated in detail by two-dimension and three-dimension finite element analyses for lensed-shaped QDs. The nonobjective isolate quantum dot system is used. The calculated results can be directly used to evaluate the conductive band and valence band confinement potential and strain introduced by the effective mass of the charge carriers in strain QD.

Optical analysis of AlGaInP laser diodes with real refractive index guided self-aligned structure

Optical modes of AlGaInP laser diodes with real refractive index guided self-aligned (RISA) structure were analyzed theoretically on the basis of two-dimension semivectorial finite-difference methods (SV-FDMs) and the computed simulation results were presented. The eigenvalue and eigenfunction of this two-dimension waveguide were obtained and the dependence of the confinement factor and beam divergence angles in the direction of parallel and perpendicular to the pn junction on the structure parameters such as the number of quantum wells, the Al composition of the cladding layers, the ridge width, the waveguide thickness and the residual thickness of the upper P-cladding layer were investigated. The results can provide optimized structure parameters and help us design and fabricate high performance AlGaInP laser diodes with a low beam aspect ratio required for optical storage applications.

中能重离子在位置灵敏CsI（Tl)探测器中能损与光输出响应的关系

In this paper, we describe the structure and readout system of a two-dimension positional sensitive CsI(Tl) detector, and investigates the relation between energy lose and light output of the CsI(Tl) detector with secondary beams in intermediate energy.Bρ+(ΔE-TOF) method was used to distinguish the secondary beam.Linearity of the position signals of the CsI(Tl) was corrected.Energy signals from the CsI(Tl) detector were calibrated using the relationship of the Z, A and the light output response of the incid...中文摘要：描述了一种双维位置灵敏CsI(Tl)探测器的结构及其读出系统,用中能次级束研究其能损与光输出关系。使用Bρ+(ΔE-TOF)方法鉴别次级束,刻度了CsI(Tl)探测器位置信号的线性,并用其光输出与入射粒子的A、Z关系刻度其能量。结果表明,CsI(Tl)探测器输出信号的ADC读出与QDC读出(即其光输出)有很好的线性关系。

Synthesis, structure and optical properties of different dimensional organic-inorganic perovskites

By varying the substituent position of aminomethyl on pyridine ring in acid solution, different dimensional lead bromide frameworks ranging from zero-dimension and one-dimension to two-dimension were obtained. 2-(Aminomethyl)pyridine (2-AMP) or 3-(aminomethyl)pyridine (3-AMP) and PbBr2 construct hybrid perovskites, of which (H(2)2-AMP)PbBr4 (1) exhibits two-dimensional perovskite sheets with special hydrogen bonds and (H(2)3-AMP)PbBr6 (2) shows an uncommon zero-dimensional inorganic framework with isolated octahedra. The characteristic exciton peaks in absorption spectra are located at 431 nm for compound 1 and at 428 nm for compound 2. (H(2)4-AMP)PbBr4 (3) with one-dimensional zigzag edge-sharing octahedral PbBr(4)(2-)chains can be obtained using 4-(aminomethyl)pyridine (4-AMP) as organic component under the same experimental conditions as those for 2-AMP and 3-AMP.

Characteristics in frequency domain by inductively coupled plasma atomic emission spectrometry with charge injection detection

The charactesistics of two-dimension spectra obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES) with charge injection detection (CID) in frequency domain were studied in the present paper. The measurement spectra were Fourier transformed and the frequency distribution of the spectra was obtained. Results showed that the spectra in frequency domain could he divided into two parts:high frequency and low frequency signals. The later stood for measurement spectra and the former for background and noises. However, the high frequecny signals could not be smoothed simply to reduce noises because the background was deteriorated even though the spectral signal did not change significantly.

基于二维位置敏感探测器的空间对接过程研究

为了准确地捕捉机器人空间对接的传感器信息,从对接机构的设计入手,研究了空间对接中传感器的选择、改制和基于传感器信息的空间对接问题.考虑到安装空间的限制和处理的信息量太多,提出了利用二维位置敏感探测器(PSD)配合红外发光器阵列的方法完成机器人的空间对接.通过对位置敏感探测器工作原理的分析和对传感器特性的试验,提出了在PSD光敏面上增加光学装置的方法以扩大它的探测范围和精度,同时大大减小了它对光信号的依赖程度.把该方法应用于可重构模块化探测机器人系统中,提出了基于传感器信息的轨迹规划方法,对子机器人空间对接过程的仿真试验验证了轨迹规划和空间对接的可行性.

企业综合自动化系统体系结构

阐述了一般综合自动化系统的二维层次体系结构，以及系统的功能、信息、资源、组织四视图在三个层次的内涵及相互关系。

二维自组织介质中地震波的传播特性

The topic of this study is simulation in the two dimensional self-organized media. The study in complexity of the earth plays an important role in structures, sources and energy seismic detection. And it mainly focuses on vertical or horizontal heterogeneous, anisotropic and linear media. Based on 2D self-organized velocity model and four-order finite-difference method, we simulate different types self-organized media and the same type mode with various parameters such as horizontal relative length, vertical relative length, variations, and velocity background gradient. Also we analyze the seismograms with complexity methods with instant information including amplitude, energy and frequency. The results can be summarized as the fallows: (1) The waveforms fluctuate with the velocity variations; (2) Different type self-organized media bring different effects on the amplitudes, energy and waveforms; (3) Different parameters also produce various influences to seismograms. (4) The layer contains their self-organized features, from which we can investigate the quality of the earth.

锦屏一级水电站高应力大断面地下洞室稳定性分析

According to the feature of high stress and large size underground tunnel , a method named DEFLAC is put forward in this paper. DEFLAC is such a method that use disturbing energy as criteria, and based on the simulating software of FLAC. Finally, the method is applied in the underground powerhouse project of Jin-Ping First-level Hydropower Station. The result is well. And some conclusions are got. (1) Based on the geological features of excavation unloading phenomena, they are concluded to three types, what’s more three corresponding mechanical modes are proposed to explain the unloading phenomena. (2) The relation of two standards , which is called GB50287-99 (T) and BQ ,is studied. And the main difference of them ,when they are applied in high stress zone ,is researched. (3) .A method named DEFLAC is put forward , which is combined disturbing energy method and FLAC simulating software. The two dimension and three dimension explicit finite difference expressions are deduced in this paper. (4) Compared the instability area achieved by FLAC and DEFLAC with the measured result, a conclusion is got. That is a more accurate result can be got by DEFLAC. (5) According to the main powerhouse first layer excavation project, the method to search and analyze the instability blocks is studied in this paper. Finally, the results got by FLAC and DEFLAC are compared .A conclusion is got that DEFLAC can judge the stability of blocks induced by intermittent joints, but Block Theory can’t. So more accurate block amount can be got by DEFLAC. It is an effective method to judge stability of blocks

南海张裂大陆边缘数值模拟研究

The South China Sea (SCS) is one of the largest marginal seas in the western Pacific, which is located at the junction of Eurasian plate, Pacific plate and Indian-Australian plate. It was formed by continent breakup and sea-floor spreading in Cenozoic. The complicated interaction among the three major plates made tectonic movement complex and geological phenomena very rich in this area. The SCS is an ideal place to study the formation and evolution of rifted continental margin and sea-floor spreading since it is old enough to have experienced the major stages of the basin evolution but still young enough to have preserved its original nature. As the demand for energy grows day by day in our country, the deep water region of the northern continental margin in the SCS has become a focus of oil and gas exploration because of its huge hydrocarbon potential. Therefore, to study the rifted continental margin of the SCS not only can improve our understanding of the formation and evolution processes of rifted continental margin, but also can provide theoretical support for hydrocarbon exploration in rifted continental margin. This dissertation mainly includes five topics as follows: (1) Various classic lithosphere stretching models are reviewed, and the continuous non-uniform stretching model is modified to make it suitable for the case where the extension of lithopheric mantle exceeds that of the crust. Then simple/pure shear flexural cantilever model is applied to model the basement geometries of SO49-18 profile in the northern continental margin of the SCS. By fitting the basements obtained by using 2DMove software with modeling results, it is found that the reasonable effective elastic thickness is less than 5km in this region. According to this result, it is assumed that there is weak lower crust in the northern continental margin in the SCS. (2) We research on the methods for stretching factor estimation based on various lithosphere stretching models, and apply the method based on multiple finite rifting model to estimate the stretching factors of several wells and profiles in the northern continental margin of the SCS. (3) We improve one-dimension strain rate inversion method with conjugate gradient method, and apply it to invert the strain rate of several wells in the northern continental margin of the SCS. Two-dimension strain rate forward modeling is carried out, and the modeling results show that effective elastic thickness is a key parameter to control basin’s geometry. (4) We simulate divergent upwelling mantle flow model using finite difference method, and apply this newly developed model to examine the formation mechanism of the northwest and central sub-basin in the SCS. (5) We inverse plate thickness and basal temperature of oceanic lithosphere using sea-floor ages and bathymetries of the North Pacific and the North Atlantic based on varied-parameters plate model, in which the heat conductivity, heat capacity and coefficient of thermal expansion depend on temperature or depth. A new empirical formula is put forward based the inversed parameters, which depicts the relation among sea-floor age, bathymetry and heat flow. Then various similar empirical formulae, including the newly developed one, are applied to examine the sea-floor spread issue in the SCS based on the heat flow and bathymetry data of the abyssal sub-basin.

复杂裂隙岩体统计断裂本构关系与变形参数研究

Rock mass is widely recognized as a kind of geologic body which consists of rock blocks and discontinuities. The deformation and failure of rock mass is not only determined by rock block，but also by discontinuity which is virtually more important. Mutual cutting and combination of discontinuities controlled mechanical property of rock mass. The complex cutting of discontinuities determine the intense anisotropy on mechanical property of rock mass，especially under the effect of ground stress. Engineering practice has show that the brittle failure of hard rock always occurs when its working stress is far lower than the yield strength and compressive strength，the failure always directly related to the fracture propagation of discontinuities. Fracture propagation of discontinuities is the virtue of hard rock’s failure. We can research the rock mass discontinuous mechanical properties precisely by the methods of statistical analysis of discontinuities and Fracture Mechanics. According to Superposition Principle in Fracture Mechanics，A Problem or C Problem could be chosen to research. Problem A mainly calculates the crack-tip stress field and displacement field on internal discontinuities by numerical method. Problem C calculate the crack-tip stress field and displacement field under the assumption of that the mainly rock mass stress field has been known. So the Problem C avoid the complex mutual interference of stress fields of discontinuities，which is called crack system problem in Fracture Mechanics. To solve Problem C, field test on stress field in the rock mass is needed. The linear Superposition of discontinuities strain energies are Scientific and Rational. The difference of Fracture Mechanics between rock mass and other materials can mostly expression as：other materials Fracture Mechanics mostly face the problem A，and can’t avoid multi-crack puzzle, while the Rock mass Fracture Mechanics answer to the Problem C. Problem C can avoid multi-discontinuities mutual interference puzzle via the ground stress test. On the basis of Problem C, Fracture Mechanics could be used conveniently in rock mass. The rock mass statistics fracture constitutive relations, which introduced in this article, are based on the Problem C and the Discontinuity Strain Energy linear superposition. This constitutive relation has several merits: first, it is physical constitutive relation rather than empirical; second, it is very fit to describe the rock mass anisotropy properties; third, it elaborates the exogenous factors such as ground stress. The rock mass statistics fracture constitutive relation is the available approach to answer to the physical, anisotropic and ground stress impacted rock mass problems. This article stand on the foundation of predecessor’s statistics fractures constitutive relation, and improved the discontinuity distributive function. This article had derived the limitation of negative exponential distribution in the course of regression analysis, and advocated to using the two parameter negative exponential distribution for instead. In order to solve the problems of two-dimension stability on engineering key cross-sectional view in rock mass, this article derived the rock mass planar flexibility tensor, and established rock mass two-dimension penetrate statistics fracture constitutive relation on the basis of penetrate fracture mechanics. Based on the crack tip plasticity research production of penetrate fracture, for example the Irwin plasticity equifinality crack, this article established the way to deal with the discontinuity stress singularity and plastic yielding problem at discontinuity tip. The research on deformation parameters is always the high light region of rock mass mechanics field. After the dam foundation excavation of XiaoWan hydroelectric power station, dam foundation rock mass upgrowthed a great deal of unload cracks, rock mass mechanical property gotten intricacy and strong anisotropy. The dam foundation rock mass mostly upgrowthed three group discontinuities： the decantation discontinuity, the steep pitch discontinuity, and the schistosity plane. Most of the discontinuities have got partial unload looseness. In accordance with ground stress field data, the dam foundation stress field greatly non-uniform, which felled under the great impaction of tectonic stress field, self-weight stress field, excavation geometric boundary condition, and excavation, unload. The discontinuity complexity and stress field heterogeneity, created the rock mass mechanical property of dam foundation intricacy and levity. The research on the rock mass mechanics, if not take every respected influencing factor into consideration as best as we can, major errors likely to be created. This article calculated the rock mass elastic modulus that after Xiao Wan hydroelectric power station dam foundation gutter excavation finished. The calculation region covered possession monolith of Xiao Wan concrete double-curvature arch dam. Different monolith were adopted the penetrate fracture statistics constitutive relation or bury fracture statistics constitutive relation selectively. Statistics fracture constitutive relation is fit for the intensity anisotropy and heterogeneity rock mass of Xiao Wan hydroelectric power station dam foundation. This article had contrastive analysis the statistics fracture constitutive relation result with the inclined plane load test actual measurement elastic modulus and RMR method estimated elastic modulus, and find that the three methods elastic modulus have got greatly comparability. So, the statistics fracture constitutive relations are qualified for trust. Generally speaking，this article had finished following works based on predecessors job: “Argumentation the C Problems of superposition principle in Fracture Mechanics, establish two-dimension penetrate statistics fracture constitutive relation of rock mass, argue the negative exponential distribution limitation and improve it, improve of the three-dimension berry statistics fracture constitutive relation of rock mass, discontinuity-tip plastic zone isoeffect calculation, calculate the rock mass elastic modulus on two-dimension cross-sectional view”. The whole research clue of this article inherited from the “statistics rock mass mechanics” of Wu Faquan（1992）.

温度、压力耦合背景下多相流体运移的数学模型研究

The Mathematical modeling of multiphase fluid flow is an important aspect of basin simulation, and also is a topic of geological frontier. Based on coupling relation of temperature, pressure and fluid flow, this dissertation discusses the modeling which conform to geological regularities of fluid migration. The modeling that is multi-field and multiphase includes heat transport equation, pressure evolvement equation, solution transport equation and fluid transport equation. The finite element method is effective numerical calculation methods. Author applies it to solve modeling and implements the finite element program, and the modeling is applied to Ying-Qiong Basin. The channels of fluid vertical migration are fault, fracture and other high penetrability area. In this thesis, parallel fracture model and columnar channel model have been discussed, and a characteristic time content and a characteristic space content been obtained to illustrate the influences of stratigraphic and hydrodynamic factors on the process. The elliptoid fracture model is established and its approximately solution in theory is gotten. Three kinds of modeling are applied to analyze the transient variation process of fluid pressure in the connected permeable formations. The elliptoid fracture model is the most similar geology model comparing with the other fracture models so the research on this fracture model can enhance the understanding to fluid pressure. In the non-hydrodynamic condition, because of the difference between water density and nature gas density, nature gas can migrate upon by float force. A one-dimension mathematical model of nature gas migration by float force is established and also applied to analyze the change in the saturation of gas. In the process of gas migration its saturation is non-continuous. Fluid flow is an important factor which influences the distribution of the temperature-field, the change of temperature can influence fluid property (including density, viscidity, and solubility),a nd the temperature field has coupling relations to the fluid pressure field. In this dissertation one-dimension and two-dimension thermal convection modeling is developed and also applied to analyze convective and conductive heat transfer. Author has established one-dimension and two-dimension mathematical modeling in which fluid is a mixture of water and nature gas based on the coupling relation between temperature and pressure, discussed mixture fluid convection heat transfer in different gas saturation, and analyzed overpressure form mechanism. Based on geothermal abnormity and pore pressure distribution in Dongfong 1-1, Yinggehai Basin, South China Sea, one-dimension mathematical modeling of coupling temperature and pressure is established. The modeling simulates the process that fluid migrates from deep to shallow and overpressure forms in shallow. When overpressure is so large that fractures appear and overpressure is released. As deep fluid flow to shallow, the high geothermal then forms in shallow. Based on the geological characteristics in Ya13-1, two-dimension mathematical modeling of coupling temperature and pressure is established. Fluid vertically flows in fault and then laterally migrates in reservoir. The modeling simulates the geothermal abnormity and pore pressure distribution in reservoir.

幼儿绘画表征的发展－－发展过程及其影响因素

Two major questions in this study are the development of children's representative drawing and the influence of semantic representation and image representation on it. Children aged from 3 and a half to 7 participated the experiments. Two-dimension and three-dimension displays were used in four experiments. The results show that: The development of children's representational drawing can be divided into stages. They become maturer in selecting the strategies of the representational drawing, which are different in nature across different ages. There is a development from feature processing to integrative processing in children's drawing. At the feature processing stage, the typological features are represented easily. No matter global or partial. They tend to use unconnected parts to represent, which is called the strategy of distributed representation, those displays without prominent features. In integrative processing stage, the features of two-dimension display are integrated according to its gestalt. And the features of three-dimension display are integrated by its prototypical view across the main axis of the display. Cubic representations were found in some of the children's drawings, but none of them can do it from a perspective view before 7 years old. The semantic processing of the display, both global and partial meaning, can influence the development of the representational drawing. The structural features of the display influence the development of drawing representation. Semantic principles and structural features influence the representational drawings together. For three-dimension display, the semantic face and structural face coexist and work together. Children's ability to draw the display according to the right perspective rather than the prototypical view increase along with them growing up.