半导体物理效应与光电子高技术产业

阐述了能带理论和晶格动力学的创建对半导体科学技术发展的历史意义，重点介绍了若干关键性半导体物理效应的内涵及其对光电子器件与技术发展所作出的源头性贡献，描绘了以半导体激光器为代表的现代光电子高科技产业的发展现状与趋势，指出了光电子高科技持续发展的主要方向。

RCE光电探测器顶部 DBR的优化（英文）

对研制的VCSEL结构外延片制成的谐振腔增强型(简称RCE)光电探测器进行了物理分析和实验研究，由于VCSEL与RCE光电探测器对谐振腔反射镜的反射率要求不同，通过腐蚀VCSEL器件顶部DBR，改变顶镜反射率，能够得到量子效率峰值和半宽优化兼容的RCE光电探测器，实现VCSEL与RCE探测器的单片集成。

An analysis of the performance of a new high-speed single-way analog switch

This paper introduces a new highspeed single-way analog switch which has both highspeed high-resolution mono-direction analog transmission gate function and high-speed digital logic gate function with normal bipolar technology. The analysis of static and transient switching performances as an analog transmission gate is emphasized in the paper. In order to reduce the plug-in effect on high-speed high-resolution systems, an optimum design scheme is also given. This scheme is to achieve accelerated dynamic response with very low bias power dissipation. The analysis of PSPICE simulation as well as the circuit test results confirms the feasibility of the scheme. Now, the circuit has been applied effectively to the designs of novel highspeed A/D and D/A converters.

Influences of initial nitridation process on the optical and structural characterization of GaN layer grown on sapphire (0001) by metalorganic chemical vapor deposition

In this paper. we investigate the influences of the initial nitridation of sapphire substrates on the optical and structural characterizations in GaN films. Two GaN samples with and without 3 min nitridation process were investigated by photoluminescence (PL) spectroscopy in the temperature range of 12-300 K and double-crystal X-ray diffraction (XRD). In the 12 K PL spectra of the GaN sample without nitridation, four dominant peaks at 3.476, 3.409 3.362 and 3.308 eV were observed, which were assigned to donor bound exciton, excitons bound to stacking faults and extended structural defects. In the sample with nitridation, three peaks at 3.453, 3.365. and 3.308 eV were observed at 12 K, no peak related to stacking faults. XRD results at different reflections showed that there are more stacking faults in the samples without nitridation.

黑土稻田CH_4与N_2O排放及减排措施研究

目前国内稻田生物源温室气体CH_4和N_2O排放的研究主要集中在潮土、红壤与水稻土上，黑土上尚未得到CH_4与N_2O排放的相关数据。本文采用封闭式箱法对黑土稻田CH_4和N_2O排放通量进行了观测，为准确估算不同土壤类型稻田生物源温室气体排放量提供了科学依据。研究发现水稻生长季CH_4排放量低于全国其它地区稻田。CH_4和N_2O排放之间存在互为消长关系(r=-0.409, p<0.05）。本试验对不同水分和肥料管理条件下稻田CH_4和N_2O通量进行测定，结果表明，间歇灌溉条件下与长期淹灌相比，CH_4排放平均通量明显减少而N_2O略有增加，其相对综合温室效应减少，水稻产量未受影响，间歇灌溉可用作减少温室气体排放的措施。土壤排放的CH_4和N_2O是微生物的代谢产物，通过对CH_4和N_2O产生相关的微生物菌群（产甲烷菌、甲烷氧化菌、硝化菌、反硝化菌）数量的测定，深入研究它们之间的关系，可以更好的从本质上认识CH_4和N_2O产生及其排放特性。研究结果为，产甲烷菌数与CH_4排放呈显著性正相关(R~2=0.77，P<0. 05),甲烷氧化菌起减少CH_4排放的作用，硝化菌数和反硝化菌数与NZO排放有密切联系。

Non-modal instabilities of two-dimensional disturbances in plane Couette flow of a power-law fluid

Instabilities of fluid flows have traditionally been investigated by normal mode analysis, i.e. by linearizing the equations of flow and testing for unstable eigenvalues of the linearized problem. However, the results of eigenvalue analysis agree poorly in many cases with experiments, especially for shear flows. In this paper we study the instabilities of two-dimensional Couette flow of a polymeric fluid in the framework of non-modal stability theory rather than normal mode analysis. A power-law model is used to describe the polymeric liquid. We focus on the response to external excitations and initial conditions by examining the pseudospectra structures and the transient energy growths. For both Newtonian and non-Newtonian flows, the results show that there can be a rather large transient growth even though the linear operator of Couette flow has no unstable eigenvalue. The effects of non-Newtonian viscosity on the transient behaviors are examined in this study. The results show that the "shear-thinning/shear-thickening" effect increases/decreases the amplitude of responses to external excitations and initial conditions. (C) 2010 Elsevier B.V. All rights reserved.

Brownian dynamics simulation of the crystallization dynamics of charged colloidal particles

Crystal formation process of charged colloidal particles is investigated using Brownian dynamics (BD) simulations. The particles are assumed to interact with the pair-additive repulsive Yukawa potential. The time evolution of crystallization process and the crystal structure during the simulation are characterized by means of the radial distribution functions (RDF) and mean square displacement (MSD). The simulations show that when the interaction is featured with long-range, particles can spontaneously assemble into body-centered-cubic (BCC) arrays at relatively low particle number density. When the interaction is short-ranged, with increasing the number density particles become trapped into a stagnant disordered configuration before the crystallization could be actualized. The simulations further show that as long as the trapped configurations are bypassed, the face-centered-cubic (FCC) structures can be achieved and are actually more stable than BCC structures. (C) 2010 Elsevier Inc. All rights reserved.

Instabilities and transient behaviors of a liquid film flowing down a porous inclined plane

The nonmodal linear stability of a falling film over a porous inclined plane has been investigated. The base flow is driven by gravity. We use Darcy's law to describe the flow in the porous medium. A simplified one-sided model is used to describe the fluid flow. In this model, the influence of the porous layer on the flow in the film can be identified by a parameter beta. The instabilities of a falling film have traditionally been investigated by linearizing the governing equations and testing for unstable eigenvalues of the linearized problem. However, the results of eigenvalue analysis agree poorly in many cases with experiments, especially for shear flows. In the present paper, we have studied the linear stability of three-dimensional disturbances using the nonmodal stability theory. Particular attentions are paid to the transient behavior rather than the long time behavior of eigenmodes predicted by traditional normal mode analysis. The transient behaviors of the response to external excitations and the response to initial conditions are studied by examining the pseudospectral structures and the energy growth function G(t) Before we study the nonmodal stability of the system, we extend the results of long-wave analysis in previous works by examining the linear stabilities for streamwise and spanwise disturbances. Results show that the critical conditions of both the surface mode and the shear mode instabilities are dependent on beta for streamwise disturbances. However, the spanwise disturbances have no unstable eigenvalue. 2010 American Institute of Physics. [doi:10.1063/1.3455503]