npn AlGaN/GaN HBT模型与特性分析

基于实验数据对GaN材料的少子寿命和碰撞电离率进行了建模,应用漂移-扩散传输模型开展了npnAlGaN/GaN异质结双极晶体管的特性研究,给出了器件导通电压、偏移电压和饱和电压的解析式.结果表明:实际器件导通电压、偏移电压及饱和电压较大的原因主要是高基区电阻和基区接触的非欧姆特性,为器件的工艺制造提供了理论指导.     

Phase Transition VO2 Thin Films for Optical Switches

This paper presents a method to make vanadium dioxide (VO₂) crystallites on silicon substrates by reactive ion beam sputtering. The thickness of the thin film is about 100nm. The phase transition temperature of VO₂ is 65°C. The transmittance of the semiconducting phase VO₂ is about 50% and it is reduced to as low as 3% in metal phase at the infrared wavelenghth spectrum. The extinction ratio of the optical switches is 12dB. and the insertion loss is of 1-2dB. The switching time is about 1ms.     

Copper-D-penicillamine complex as potential contrast agent for MRI.

In vitro and in vivo proton T1 data are reported that demonstrate that the paramagnetic copper-D-penicillamine complex can be applied as a potential contrast agent to magnetic resonance imaging.     

Study of coupling between circular groove guide and rectangular groove guide

On the basis of the studies of single circular groove guide and single rectangular groove guide, the coupling of the two waveguides has been researched and the characteristic equation of circular—rectangular groove guide has been given in this paper.     

Navier-Stokes方程带Backtracking技巧的两重网格算法

1 引 言考虑二维不可压 Navier-Stokes方程:     

宽带无线接入系统WiMAX的应用与部署

介绍了宽带无线接入系统WiMAX的关键技术，并与其他接入技术作了比较；阐述了WiMAX的主要应用、组网部署；也指出了WiMAX存在的一些主要问题。     

互联网业务流量监测技术的应用和设计

对互联网业务流量监测技术的应用及现状进行了分析，并针对NetFlow技术，对互联网业务流量监测系统建设方案设计中需要考虑的几个重要问题进行了讨论。     

Competitive influence of atactic polystyrene and supercritical carbon dioxide on the conformation of syndiotactic polystyrene

The crystallization behavior of miscible syndiotactic polystyrene (sPS) and atactic polystyrene (aPS) blends with different sPS/aPS weight ratios was investigated in supercritical CO₂ by using Fourier‐transform infrared spectroscopy, differential scanning calorimetry, and wide‐angle X‐ray diffraction. Supercritical CO₂ and aPS exhibited different effects on the conformational change of sPS and competed with each other. Increasing the content of amorphous aPS in the blends made its effect on the conformational change of sPS gradually surpass that of supercritical CO₂. Supercritical CO₂ favored the formation of the helical conformation of sPS in lower temperature range and the all trans planar conformation in higher temperature range, instead of forming the latter one only in higher temperature range in ambient atmosphere. However, increasing aPS content in the blends pushed the range for forming the helical conformation to lower temperature and made the all trans planar conformation dominant in aPS/sPS 25/75 blend after treating in supercritical CO₂ above 60 °C. The all trans planar zigzag conformation was more favorable than the helical conformation after mixing aPS in sPS in supercritical CO₂. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1755–1764, 2007