~(137)Cs示踪技术背景值研究进展与建议

利用环境核素137Cs示踪技术研究土壤侵蚀被越来越多的科研人员所采用,而背景值的确定是利用该技术研究土壤侵蚀的前提和根本,直接关系到侵蚀速率计算的准确与否。本文从137Cs背景值采样点的选取方式,137Cs全球空间分布预报模型以及影响137Cs沉降因素等方面进行了总结性综述,对137Cs背景值研究应注意的问题和今后研究重点提出了建议。

AlGaN／GaN异质结紫外探测器

采用p-AlGa1-xN／i-GaN／n-GaN异质结构成功制备了含铝组分分别为0．1和0．07的正照射可见盲紫外探测器，并分别测试了它们的伏安特性曲线和光电响应光谱。对于Al组分为0．1的器件，在零偏压处出现了板低的暗电流密度，表明器件具有非常高的信噪比。高分辨率X射线衍射仪对材料的测试结果表明，高铝组分（0．1）窗口层薄膜材料的晶体质量较差，导致暗电流增大，而其窗口层的窗口选择作用则可以得到较高的响应率和较宽的响应波段。

光调制技术测量半导体激光器固有高频响应

采用一种新的全光纤连接的半导体激光器光调制技术,实现了对高速半导体激光器固有响应的直接测量。利用速率方程能够对光调制的动态响应过程进行准确的描述。基于对抽运源和探测器的频率响应对光调制数据准确性影响的分析,通过将网络分析仪校正到同轴端,然后用直接扣除法和相互扣除法,在网络分析仪外部对测量数据进行了修正。两种修正方法得到了一致的结果,并且同已有的理论和实验结果相符合。改进后的光调制技术和两种修正数据的方法不但提高了数据的精确性,而且扩展了测量的频率范围。

Design of Tapered Rib Spot-Size Converter with Double-Cladding Structure

A novel structure of spot-size converter is designed to allow low loss and large alignment tolerance between single-mode rib waveguide devices and fiber arrays theoretically. The spot-size converter consists of a tapered rib core region and a double-cladding region. Through optimizing parameters,an expanded mode field can be tightly confined in the inner cladding and thus radiation loss be reduced largely at the tapered region. The influence of refractive index and thickness of the inner cladding on coupling loss is analyzed in particular. A novel,easy method of fabricating tapered rib spot-size converter based on silicon-on-insulator material is proposed.

LEC GaAs中缺陷的光致发光研究

于2010-11-23批量导入

基于.NET的四层结构及其在综合信息系统中的应用

阐述应用程序开发的三层结构的基本组织形式及存在的问题,提出了基于四层结构的应用程序开发模型及其带来的好处.结合七里村采油厂综合信息系统开发实例,对基于.NET的四层结构的应用程序开发技术进行了研究,实现了基于.NET的四层结构的部署,阐述了基于四层结构的具体实现策略,并在此基础上给出了基于四层结构的应用程序设计与开发的关键技术.

Splitting the Fast and Slow Motions in Molecular Dynamics Simulations Based on the Change of Cold Potential Well Bottom

The atomic motion is coupled by the fast and slow components due to the high frequency vibration of atoms and the low frequency deformation of atomic lattice, respectively. A two-step approximate method was presented to determine the atomic slow motion. The first step is based on the change of the location of the cold potential well bottom and the second step is based on the average of the appropriate slow velocities of the surrounding atoms. The simple tensions of one-dimensional atoms and two-dimensional atoms were performed with the full molecular dynamics simulations. The conjugate gradient method was employed to determine the corresponding location of cold potential well bottom. Results show that our two-step approximate method is appropriate to determine the atomic slow motion under the low strain rate loading. This splitting method may be helpful to develop more efficient molecular modeling methods and simulations pertinent to realistic loading conditions of materials.

昆仑山北坡鸭子泉河阶地发育及其构造-气候意义

IEECAS SKLLQG

微波辐射对菘蓝种子生理及幼苗发育的影响

IEECAS SKLLQG