内嵌SCR的LDMOS器件双骤回ESD特性研究

基于寄生参数分析,对内嵌SCR的LDMOS器件给出了二次骤回发生判据。本文对三种典型结构进行了数值仿真和比较,并基于此判据仿真优化了影响二次骤回的器件结构参数,从而提高器件ESD性能。TLP试验数据表明,当二次骤回电压由25.4V降低到8.1V时,器件ESD泄放能力由0.57A提高到3.1A。     

等距多项式插值公式计算法

在分析了传统多项式数插值基础上,对等距情况的插值问题进行了研究,得到了等距情况的简单差商计算公式,计算量比传统方法小.最后通过实例,说明了该计算方法.     

三相不控整流器输入LC滤波器的研究

鉴于单相供电的局限性以及三相供电的优越性,目前大功率变频空调领域主要采用三相无源功率因数校正方案。在考虑校正效果以及成本、体积、重量、效率、输出电压等因素情况下,提出并分析了不控整流器采用单级LC滤波器时关键问题,包括混合谐波源等效原理、谐波电流滤波原理、输出直流电压提升原理、整流桥最佳输入线电压波形,并对搭建的最大输...     

基于ARM的机房监控系统GPRS智能巡检终端(上)

该文设计了一种用于机房监控系统的基于ARM 9处理器的GPRS智能巡检终端,采用基于ARM920T内核的S3C2410处理器来设计硬件平台,并在该处理器上移植了Linux操作系统,利用其资源编写程序实现了GPRS模块、USB摄像头等功能的应用.该文为现有大型分布式机房人工巡检难题提供了一套现实可行的解决方案.     

基于贝叶斯理论的辐射源分类识别方法研究

针对当前辐射源识别系统中存在的问题,提出了一种结合组合分类器技术的辐射源识别新方法。该方法可以准确地识别各类辐射源,实际仿真结果表明该方法是有效的。     

基于压电效应的振荡水柱发电系统CFD分析

"透明海洋"开发需要为远洋检测传感器提供可持续电源,基于压电效应的振荡水柱发电原理是采集波能驱动压电功能材料形变实现能量转换,系统结构简单,稳定性好。基于线性波浪理论,建立振荡水柱(OWC)二维数值波浪水槽。流体动力学(CFD)分析结果表明,造波稳定,波浪在气室内形成的空气压强在时域上呈现一定周期性,经数据处理拟合为正弦曲线。应用ANSYS软件系统的参数化设计语言(APDL)功能开发空气驱动压电材料形变输出能量的仿真模型,分析产生电压变化特性。     

晶体硅太阳能电池激光精细加工技术研究

为提高晶体硅太阳能电池的转换效率,采用532 nm与355 nm纳秒激光器及10.6 μm射频二氧化碳激光器对晶体硅太阳能电池的绒面制作、边缘隔离工艺以及电池前电极激光制作进行了实验研究,获得了相关的工艺参数.     

Ultrasound measurement of brachial flow-mediated vasodilator response

Brachial artery flow-mediated vasodilation is increasingly used as a measure of endothelial function. High resolution ultrasound provides a noninvasive method to observe this flow-mediated vasodilation by monitoring the diameter of the artery over time following a transient flow stimulus. Since hundreds of ultrasound images are required to continuously monitor brachial diameter for the 2-3 min during which the vasodilator response occurs, an automated diameter estimation is desirable. However, vascular ultrasound images suffer from structural noise caused by the constructive and destructive interference of the backscattered signals, and the true boundaries of interest that define the diameter are frequently obscured by the multiple-layer structure of the vessel wall. These problems make automated diameter estimation strategies based on the detection of the vessel wall boundary difficult. We obtain a robust automated measurement of the vasodilator response by automatically locating the artery using a variable window method, which gives both the lumen center and width. The vessel wall boundary is detected by a global constraint deformable model, which is insensitive to the structural noise in the boundary area. The ambiguity between the desired boundary and other undesired boundaries is resolved by a spatiotemporal strategy. Our method provides excellent reproducibility both for interreader and intrareader analyzes of percent change in diameter, and has been successfully used in analyzing over 4000 brachial flow-mediated vasodilation scans from several medical centers in the United States.     

SGDBR型激光器的波长自动控制系统

根据取样光栅分布布拉格反射器(SGDBR)型激光器的波长调谐原理,设计出用于SGDBR型激光器的波长自动控制系统.利用该系统对自行研制的SGDBR型激光器进行了准确、快速的波长扫描,为器件的动态性能研究奠定了测试基础.     

Thermoelectric Performance of Poly(3,4-Ethylenedioxy-thiophene)/Poly(Styrenesulfonate) Pellets and Films

The thermoelectric performance of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) pellets and free-standing PEDOT/PSS films, prepared from PEDOT/PSS solution containing the additives dimethyl sulfoxide or ethylene glycol, have been systematically investigated. It has been found that the electrical conductivity of free-standing PEDOT/PSS films is invariably much higher than that of PEDOT/PSS pellets, while there is no distinct change in the Seebeck coefficient. The highest electrical conductivity of a free-standing PEDOT/PSS film can be up to 300 S cm⁻¹, five to six times higher than that of PEDOT/PSS pellets (55 S cm⁻¹). The thermal conductivity was measured over a wide temperature range, indicating that PEDOT/PSS has extremely low thermal conductivity. The figure of merit (ZT) of free-standing PEDOT/PSS films with good environmental stability can be up to 10⁻², an order of magnitude higher than that of pressed PEDOT/PSS pellets (10⁻³).