连续运转的掺钛蓝宝石激光器

本文报导一种连续波氩离子激光泵浦的掺钛蓝宝石激光器。在氩离子激光功率(全谱线)为10.45瓦且仅用一组腔镜时,获得最大平均功率超过1000mW、调谐范围750～850nm的掺钛蓝宝石激光输出。     

High mobility,low voltage polymer transistor

We introduce a polymer transistor that operates with low supply voltage and yet has a field-effect mobility higher than the mobilities reported for low voltage polymer transistors. A simple plasma oxidation of the gate metal to form a thin (3.74 nm) top metal oxide layer in the gate metal is involved in the fabrication that acts as the gate dielectric. With ultrathin gate dielectrics, the variation in the dielectric thickness and the surface roughness scattering can severely limit the mobility attainable. The plasma oxidation under certain conditions produces a very smooth oxide surface, leading to the high mobility.     

CNC机床结构动态设计方法研究

提出机床结构动态设计基本原则。以某数控弧齿铣齿机为研究对象,应用相关的动态设计原则,通过变量化设计与有限元分析,对该机床进行结构动态设计。结果表明,应用该方法设计的机床结构具有良好的动静态特性。     

Inoculation mechanism of rare earth–Mg alloy in molten cast iron

The dissolution region of RE–Mg (RE=rare earth) alloy in the reaction chambers of in-mould inoculated castings was studied by scanning electron microscopy and on electron microprobe. The dissolution region of the inoculant was divided into 7 zones according to its microstructure. The RE–Mg alloy is composed of Mg2Si, a Mg2Si–Si eutectic, FeSi, RE–Mg–Si and other silicides. The dissolution of the alloy is a process in which the low melting point phases such as Mg2Si, a Mg2Si–Si eutectic and RE–Mg–Si dissolve first, and the high melting point phases such as FeSi and FeSi2 dissolve later. In addition, some intermediate products form during the dissolution process. This causes a concentration gradient of Mg and RE in the melt which results in a transition of the graphite morphology from normal spheroid to open nodule, vermicular and flake graphite. The dissolution of the FeSi phase in the melt forms local sites of high silicon concentration which promote the nucleation and growth of the graphite. © 1998 Chapman & Hall     

Neural networks modeling signal responses and taxol production of cultured Taxus chinensis cells induced by bio-elicitor

Quantitatively describing the signal transduction process is important for understanding the mechanism of signal regulation in cells, and thus, poses both a challenge and an opportunity for chemical and biochemical engineers. An artificial neural network (ANN), in which we took the signal molecules as neural nodes, was constructed to simulate the generation of active oxygen species (AOS) in Taxus chinensis cells induced by a bio-elicitor. The relative contents of AOS in cells predicted by the ANN model agreed well with the experimental data and three notable stages of AOS increase were observed from the 3D figure of AOS generation. The robustness of AOS trajectories indicated that signal regulation in vivo was an integral feedback control model that ensured the adaptation of Taxus chinensis to environmental stress. The artificial neural network was able to predict taxol production as well as determine the optimal concentration of oligosaccharides needed for it.     

EO/EG装置生产过程中有机酸的生成原因分析

分析了环氧乙烷，乙二醇装置工艺系统中有机酸生成的原因．指出在银催化剂作用下，乙烯氧化过程有机酸生成主要成分是甲酸和乙酸，银催化剂不是影响氧化反应器出口醛含量的主要因素；杂质、温度等对反应器出口气中的醛含量有重要影响，也直接影响到装置前系统的有机酸含量；乙二醇后系统中有机酸的增加仅取决于两级吸收及解析工艺的稳定操作。     

锡膏激光扫描三维测量系统光强自适应调节技术

根据锡膏激光扫描三维测量系统在测量PCB电路板时底板和锡膏对激光光强的散射效果不同,设计并研制了一套光强自适应调节光源。该光源以程控电源为基础,分析光条中心提取效果与激光光强的关系,应用小波分解与频带能量比相结合的光强自适应调节算法实现测量系统光强自适应调节功能。进行了相关实验,实验结果表明该光源能够很好地实现锡膏激光扫描三维测量系统的激光光强自适应调节,并能选出最适合测量的激光光强,具有很好的适用性。     

基于柔性阵列传感器的脉象检测系统的设计

当前的脉象仪大部分采集手段单一,取脉压力的调节性差,无法模拟医生的布指方式,而且只能实现脉搏图的描记及分析,无法给出脉象的三维信息。针对这一问题研制了基于柔性阵列传感器的脉象检测系统,用硅胶制作了专门的脉搏换能器;设计了压力控制系统,实现压力自动调节,完成了对最佳取脉压力下脉象的采集;搭建了信号处理电路,实现了对脉象信号的提取和预处理;以USB-7660为核心构建了A/D采集系统,实现了对多路脉象信号的显示、存储。实验表明,该系统不仅可以有效采集到受试者的七路二维脉图,而且能清晰地观测到受试者的脉道宽度,并重建出相应脉搏波的三维传导地形图。     

基于Gabor小波与LBP直方图序列的人脸年龄估计

提出了一种基于Gabor小波和局域二值模式(Local binary pattern,LBP)直方图序列的人脸年龄估计方法。首先对人脸图像提取多方向与多尺度的Gabor幅值域图谱(Gabor magnitude maps,GMMs);然后采用基于局部特征的LBP算子对GMMs编码,并对之分块,由各子块的直方图序列来描述人脸;为进一步降低人脸特征维数,再对人脸直方图序列特征应用主成分分析(PCA);最后使用支持向量机回归(SVR)的LOPO策略对人脸年龄库进行训练和测试。实验结果表明,该方法可以较为快速有效地对人脸图像进行年龄估计。     

数据交换传输安全模型设计及实现

在WebServices应用中,保证数据交换传输的安全性和完整性非常重要,而当前技术下的WebServices却在安全性方面存在着一些不足。为了保护在WebServices中消息交换的安全传递,文中通过X．509证书实现了WebServices消息签名和加密,阐述了利用WSE3．0构建安全WebServices的方法,设计并实现了一种基于策略的可扩展系统安全架构,其中采用了证书管理、数据同步以及用户校验三种机制。在实现架构的过程中,将安全通信主体分为Web服务端和服务应用端,并通过对系统安全性的分析验证,证明此架构具有良好的安全性。随着信息化技术的发展,安全架构中安全策略的应用会越来越广泛和深入。