GPIB通信在电容测试仪表校准中的应用

安捷伦电容测试仪表(E4980A,4279A)每年需要做年度校准,人工手动校准操作非常复杂且耗时过长。但是运用电容仪表通信协议,年度校准完全可以实现自动化。通过VB编程加GPIB通信的方法编写测控软件,可以实现软件自动发送所有的校准指令,自动判断仪表返回校准数值正确与否,自动保存校准数据为Excel文件同时录入数据库,实现了快速高效的电容测试仪表的校准。     

数据库的加解密操作

FoxPro数据库系统没有直接提供对文件的加密和解密操作,而有时为了数据的安全可靠,应该对文件加密和解密。由于FoxPro系统提供了对文件进行低层操作的函数,我们不难构造文件的加密或解密函数。文中提供的加密算法是过于简单的,只是表达一个加密的思想,而不是构造一个非常实用的函数,读者可在其基础上自行修改成一个实用的函数。 以下是数据库加密解密所涉及的两个函数的清单(可     

VFP字段加／解密算法的实践

按字段级和文件级对VFP数据加密/解密方法进行了分类,详细分析了这两种方法的优缺点,指出了用传统的二进制I/O方式对数据库文件加密/解密较难适应Windows环境的原因,进而从密码学的角度叙述了多随机数加密技术的加密/解密的原理,阐述了多随机数加密/解密算法技术的特点及实现方法,并给出数据库字段加密/解密算法的实现函数.     

使用PGP确保数据隐密和完整

GnuPG简介 如何保证在不安全的网络上传输的数据的安全性？本文将通过具体的加解密实例，为您介绍Linux下的基于PGP（Pretty Good Privacy）机制的加密及签名软件——GnuPG，包括密钥生成、公钥导出、加密文件、解密文件、对文件进行数字签名等重要步骤。     

数据库加,解密技术分析

列举了信息管理系统中保证数据安全的几种方法，分析了对数据库文件进行加密和解密的途径，并给出了ＦｏｘＰｒｏ数据库文件加密和解密的通用程序。     

文件／文件夹“强力保护”

软件名称：宏杰文件央加密 软件属性：加密解密 运行平台：Windows2000／2003／XP／Vista／7     

一种SWF文件版权保护简单实现方案

本文设计了加密器与带有即时解密功能的播放器来进行对swf文件版权保护。加密器就利用AES加密方式对swf格式文件进行整体加密,从而防止当今流行的反编译软件的攻击。同时能在加密时指定文件的使用期限(即过期时间)。在播放文件之前播放器会提示密码输入以及过期提醒。在关闭播放器时会清除硬盘上的临时数据以防止泄漏。     

多用户环境下的数据加密

“大狼狗加密专家”是由国内公司开发设计的一款加密工具,它采用高强度PKI加密技术,具有“文件夹加密、文件加密、磁盘保险箱（磁盘加密）、安全文件夹、指定解密人、制作自解密文件”等强大功能,可以有效地保护用户隐私数据的安全。     

涉密数据流向的透明加密系统设计

目前大多数透明加密技术都是依靠监控系统的进程来完成,这样就必须对所使用的软件进行限制,并且根据使用软件的升级而更新,对不支持的软件和进程则无法实现数据加密。文中揭示了一种基于涉密数据流向的透明加解密系统及方法,使得在本地数据的透明加解密不再依赖于对系统使用程序的限制,而是通过对涉密数据流向进行监控,结合对磁盘写入数据进行对比实现。只要对磁盘重要的文件进行指定加密,就既实现了对机密数据的防泄密,又实现了对未涉密数据的有效甄别,防止了过度加密带来的数据交流上的麻烦。     

网络传输透明加密系统设计与实现

随着计算机网络的普及和加密技术的发展,透明加密技术已经成为目前企业等单位用于文档数据保密的首选。文件的透明加密技术具有以下特点:不影响使用者的原有操作习惯,自动对需要保护的文件进行加密和解密,并且保存在磁盘上的文件始终是已经过加密的。在网络环境下的文件传输中,利用透明加密技术对文件加以保护也是十分必要的。但是,用于加密和解密的密钥应该仅由已授权的用户保管,通常是使用者个人。因此,对于网络传输的透明加密,如何使密钥在不同的使用者之间完成交换共享成为一个关键的问题。针对这个问题以及透明加密技术的特点,开发一个文件的网络传输透明加密系统,实现了应用于网络传输的文件透明加密等功能。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.