A physical and scalable I-V model in BSIM3v3 for analog/digitalcircuit simulation

A new physical and continuous BSIM (Berkeley Short-Channel IGFET Model) I-V model in BSIM3v3 is presented for circuit simulation. Including the major physical effects in state-of-the art MOS devices, the model describes current characteristics from subthreshold to strong inversion as well as from the linear to the saturation operating regions with a single I-V expression, and guarantees the continuities of I_ds, conductances and their derivatives throughout all V_gs, V_ds, and T_bs, bias conditions. Compared with the previous BSIM models, the improved model continuity enhances the convergence property of the circuit simulators. Furthermore, the model accuracy has also been enhanced by including the dependencies of geometry and bias of parasitic series resistances, narrow width, bulk charge, and DIBL effects. The new model has the extensive built-in dependencies of important dimensional and processing parameters (e.g., channel length, width, gate oxide thickness, junction depth, substrate doping concentration, etc.). It allows users to accurately describe the MOSFET characteristics over a wide range of channel lengths and widths for various technologies, and is attractive for statistical modeling. The model has been implemented in the circuit simulators such as Spectre, Hspice, SmartSpice, Spice3e2, and so on     

Excess noise in GaAs avalanche photodiodes with thin multiplicationregions

It is well known that the gain-bandwidth product of an avalanche photodiode can be increased by utilizing a thin multiplication region. Previously, measurements of the excess noise factor of InP-InGaAsP-InGaAs avalanche photodiodes with separate absorption and multiplication regions indicated that this approach could also be employed to reduce the multiplication noise. This paper presents a systematic study of the noise characteristics of GaAs homojunction avalanche photodiodes with different multiplication layer thicknesses. It is demonstrated that there is a definite “size effect” for multiplication regions less than approximately 0.5 μm. A good fit to the experimental data has been achieved using a discrete, nonlocalized model for the impact ionization process     

UV-LIGA光刻设备研究

近几年来微型机电系统 (MEMS)的研究得到了高速的发展 ,而MEMS的工艺基础是微细加工技术。针对电铸 (LIGA)技术所存在的缺点提出了紫外光电铸(UV -LIGA)技术 ,并研制了用于UV -LIGA技术的光刻设备。其中介绍了整机的设计要点、所解决的关键单元技术和实验结果。     

计算机局域网（上）

本文简要地讨论了计算机局网的基本技术、协议和标准，并对几个典型的局域网便子作了概要的介绍。     

ATM组播交换系统的一种信元调度算法

对于输入缓冲和输出缓冲ATM组播交换系统,目前主要有两种信元调度算法:窗口调度算法和输出缓冲算法。这两种算法分别用于输入缓冲和输出缓冲系统中,其缺点是对处理器速度和存储器访问速度要求较高。笔者给出的算法对交换网络的处理速度和存储器访问速度要求不高。可以大大改善了交换机的延迟-吞吐率性能。     

光纤光缆的偏振模色散系数研究

本给出了在不同的外界条件下的一些光纤和光缆的偏振模色散系数的测量值，而且对测量结果进行了讨论和分析。     

An aperture-coupled linear microstrip leaky-wave antenna array withtwo-dimensional dual-beam scanning capability

This paper describes an X-band 4×1 aperture-coupled series-fed electronically steerable microstrip leaky-wave antenna (LWA) array design, which has dual-beam radiation pattern and two-dimensional (2-D) beam-scanning capability. The LWA array is operated in the first higher order mode and excited by center-fed aperture coupled for dual-beam operation. The varactor-tuned phase shifters are placed between the antenna elements. The measured half-power beamwidth of the H-plane and quasi-E-plane radiation patterns are less than 30°. By tuning the reverse dc bias of the varactor diodes, the main beam can be scanned in azimuth plane from -13° to +13° off broadside. In the elevation plane, the beam-scanning angle is close to 20° as the operating frequency tuned from 11.58-12.5 GHz. Taking into account each phase-shifter insertion loss and phase progression, the measured results compared closely with the theoretical prediction. The proposed antenna array is suitable for wireless communication and collision warning radar systems     

两种波长激光血管内照射生物效应比较

目的：研究同等照射条件的低强度532nm与633nm激光血管内照射生物效应的特点。方法：用532nm和633nm激光对健康大耳白家兔血管内照射，平均照射功率均设定在5mW左右，照射总能量约12J。两组家兔均于照前及照后1d、4d、7d、11d采集外周血，检测血浆ET、NO、MDA含量和SOD活性。结果：两组家兔上述各指标随照后时间的变化规律相似，经方差分析组间各指标都没有显著性差异。结论：同等照射条件下，低强度532nm与633nm激光照射血液的生物效应相似。     

ADHOC按需路由协议的仿真与性能分析

介绍了ADHOC网络中路由协议的基本概念和特殊性，引出三种具有典型性的按需路由协议：DSR、AODV、TORA，接下来用OPNET软件对这三种路由协议在不同的网络规模、网络拓扑变化快慢程度下进行仿真，并从路由分组开销、网络时延和分组投递率几个方面进行对比分析论证，得出这3种路由协议在不同场景下的性能特点。     

变频器在北京地铁五号线隧道风机应用

地铁工程车站可逆转高温轴流风机，区间风井隧道可逆转轴流风机，一般设于车站两端或区间通风机房内，用于车站、区间隧道通风。以前采用的是星一角启动，风阀调节方式，近几年来各大城市新增地铁项目中逐渐采用变频器和软启动器控制车站风机。本文结合北京地铁五号线的实际要求，详尽地介绍了地铁车站风机变频器控制要求，及施耐德ATV38变频器在该系统中的应用。