Ni(Zr)Si薄膜热稳定性及其肖特基势垒二极管的电学特性

提出在Ni中掺人夹层Zr的方法来提高NiSi的热稳定性.具有此结构的薄膜,600～800℃快速热退火后,薄层电阻保持较低值,小于2Ω/□.经XRD和Raman光谱分析表明,薄膜中只存在低阻NiSi相,而没有高阻NiSi2相生成.Ni(Zr)Si的薄层电阻由低阻转变为高阻的温度在800℃以上,比没有掺Zr的镍硅化物的转变温度上限提高了100℃.Ni(Zr)Si/Si肖特基势垒二极管能够经受650～800℃不同温度的快速热退火,肖特基接触特性良好,肖特基势垒高度为0.63eV,理想因子接近于1.     

适用于10/100Base-T以太网的低抖动频率综合器

设计了一种用于10/100Base-T以太网收发器的频率综合器电路.该电路自适应工作在10和100Mbps两种模式下,并能自由切换.电路采用cascode电流源、差分对称负载延迟单元等优化结构,使时钟输出具有良好特性,且能兼具DLL功能,同时满足发送电路上升下降斜率控制和时钟恢复电路对于多相时钟的需要,避免额外的功耗和面积.在一定测试环境下,晶振的cycle-cycle抖动σ约为25ps,输出时钟分频后的25MHz测试时钟信号的σ仅为22ps.测试结果表明,时钟发生电路具有良好的工艺稳定性和较强的抑制噪声能力,满足发送和接收电路对于时钟性能的要求.芯片采用SMIC 0.35μm的标准CMOS工艺,电源电压为3.3V.     

Multiuser detectors for synchronous DS-CDMA systems based on a recursive p-norm convex relaxation approach

Multiuser detectors for direct-sequence code-division multiple-access (DS-CDMA) systems based on a recursive convex programming (RCP) relaxation approach are proposed. In these detectors, maximum likelihood (ML) detection is carried out in two steps: first, the combinatorial problem associated with ML detection is relaxed into a convex programming problem and then a recursive approach is applied to get an approximate solution for ML detection. Computer simulations demonstrate that the bit-error rate performance offered by the new detectors is near-optimal and superior to that offered by many existing suboptimal detectors including some recently proposed semidefinite-programming relaxation (SDPR) detectors. In addition, the amount of computation required by the RCP detectors is much less than that required by SDPR detectors.     

A 22-GHz push-push CMOS oscillator using micromachined inductors

This letter presents a low phase noise 0.35-/spl mu/m CMOS push-push oscillator utilizing micromachined inductors. This oscillator results in an improvement in phase noise compared with the previously published Si-based voltage-controlled oscillators (VCOs) around 20GHz. With the high-Q inductors introduced by the micromachined structure, the oscillator achieves an oscillating frequency of 22.2GHz while exhibiting an output power of -7.5dBm with a phase noise of -110.1dBc/Hz at 1-MHz offset. This work also demonstrates the highest operating frequency among previously published Si-based VCOs using micromachined structures.     

Realization of GaAs/AlGaAs quantum-cascade lasers with high average optical power

Quasi-continuous-wave operation of GaAs/AlGaAs quantum-cascade lasers with high average optical power is demonstrated. Double X-ray diffraction has been used to investigate the quality of the epitaxial material. The compositional gradients and the interface quality are controlled effectively. The corrected average power of per facet about 17 mW and temperature tuning coefficient of the gain peak about 0.91 nm/K from 83 K to 140 K is achieved in pulse operation. Best value of threshold current density is less than 3.0 kA/cm² at 83 K.     

电学仿真软件的现状与发展

1仿真技术的概念及范畴 仿真技术是以相似原理、系统技术、信息技术以及仿真应用领域的相关专业技术为基础,以计算机系统、与应用有关的物理效应设备及仿真器为工具,利用模型对系统(已有的或设想的)进行研究的一门多学科的综合性技术.     

Detection Probability Estimation of Directional Antennas and Omni-Directional Antennas

This paper studies the problem of detection of directional antennas and omni-directional antennas by hostile detection systems. We present a model for calculating the probability of detecting a transmitter at arbitrary location around the transmitter. Our study shows that, if a directional antenna employs the same transmit power as an omni-directional antenna, the directional antenna can not decrease the probability of being detected. In some scenarios, a directional antenna is more likely to be detected than an omni-directional antenna. However, if a directional antenna provides the same Effective Isotropic Radiated Power in the direction of the receiver as an omni-directional antenna, the transmit power needed by a directional antenna to send data is much less than that of an omni-directional antenna. In this scenario, the probability of detecting a directional antenna is reduced by over 90%. This reveals that directional antennas can be used to build a secure path to send data at low probability of being detected by adversaries.     

广播电台发展手机网业务的思考

广播电台作为传统媒体的一员,既不同于电视与报纸,更需要面对传统媒体和新媒体的竞争。它需要利用自身的优势,处理好竞争与渗透关系,从众多新媒体的发展中找到属于自己的发展道路。本文将对其进行尝试性的探讨,寻找广播电台发展新媒体业务的切入点。     

弹道修正火箭的捷联惯姿算法比较研究

针对灵巧弹药的特殊运动规律,对采用高精度惯姿算法改善弹道修正引信姿态探测精度进行探讨和研究。采用一种精确积分角增量的方法,对传统等效旋转矢量算法进行了修正,通过仿真验证了算法的性能,结果表明修正算法的精度具有一定的优势,为基于MEMS速率陀螺的弹载全姿态探测模块的工程化研究提出有益的建议。