TNC架构的应用研究

可信网络连接(TNC)是由60多家可信赖计算机组织TCG的成员共同开发的。TNC是基于完整性和认证性双重概念开发的,TNC架构提供了在不同网络环境中采集和交换端点完整性数据的通用框架。本文定义了TNC架构的基本元素,介绍了TNC与现有网络标准和设备的关系,并研究了如何在现有网络环境下应用TNC架构的问题。     

分解大数质因子的量子算法--Shor算法

分解大数质因子的Shor算法的提出,对RSA公钥密码体系构成了很大的威胁,并掀起了研究量子计算机的高潮。分析了RSA公钥密码体系的安全性,并介绍了Shor算法的基本思想。     

PTH孔内无铜的预防

通过观察PTH线的不同类型孔内无铜现象,针对PTH的流程特性,制定相应的预防措施,以求最大限度的减少孔内无铜发生。     

Quantitation of caffeine by capillary zone electrophoresis with end-column amperometric detection at a carbon microdisk array electrode

Capillary zone electrophoresis is employed for the determination of caffeine using end-column amperometric detection with a carbon fiber microdisk array electrode at a constant potential of 1.45 V versus a saturated calomel electrode. The optimum conditions of separation and detection are 0.1 52mM NaH2PO4-0.648mM Na2HPO4 for the buffer solution, 20 kV for the separation voltage, 5 kV for the injection voltage, and 10s for the injection time. The limit of detection is 2.9 x 10(-4)mM or 1.2 fmol (signal-to-noise ratio = 2). The relative standard deviation is 0.68% for the migration time and 2.3% for the electrophoretic peak current. The method is applied to determining caffeine in human serum and a cola drink.     

Flow injection kinetic spectrophotometric determination of ascorbic acid based on an inhibiting effect

A rapid and sensitive flow-injection kinetic spectrophotometric method is proposed for the determination of ascorbic acid. The procedure is based on the inhibiting effect of ascorbic acid on the enhancing effect of oxalate on the potassium dichromate-potassium iodide/rhodamine 6G system. The detection limit and linear ranges are 0.08 and 0.10-4.00 microg/ml, respectively. The relative standard deviation of 11 replicate measurements is less than 2.0%. This method has been successfully used to determine ascorbic acid in pharmaceuticals, tomatoes and oranges.     

Optical nonlinearity and structural phase-transition observation of organic dye-doped polymer silica hybrid material

The optical nonlinearity of organic dye-doped poly(methyl methacrylate) (PMMA)-silica-gel hybrid material was investigated by second-harmonic-generation measurement. We found that incorporation of in situ polymerized solgel precursors into the organic dye-doped PMMA significantly improved the nonlinear optical stability of the system. However, improvement of thermal stability occurred only when a sufficient amount of silica gel was incorporated. A structural phase transition from pure polymer to a hybrid system was found near a 10-mol.% silica-gel concentration. The optimum polymer/tetraethoxysilane molar ratio is 2:1 to 1:1.     

0.18μm数字CMOS工艺下的高增益运算放大器设计

基于SMIC 0.18μm数字CMOS工艺,设计了一种基于增益增强技术的折叠式共源共栅运算放大器,并采用衬底校准技术增大了运放的输入摆幅,可用于13位30MHz采样频率的流水线模数转换器,分析了受流水线性能限制的运放性能.仿真结果表明运放在1V的输入摆幅下开环增益大于100dB,8.5pF负载电容下单位增益带宽为322MHz,功耗仅为1.9mW.     

SUPPLEMENT TO “PASSAGE, BLOCKADE, SINK AND SOURCE OF A PLANAR DYNAMICAL SYSTEM”

A Theorem is given on the number of passages passing throgh a multiply-connected region,which corrects a wrong conjecture in a former paper of the author.     

Optical phase locked-loop homodyne receiver using an eight-port 90° optical hybrid

The performance of a PSK optical phase locked-loop (PLL) homodyne system based on an eight-port 90° optical hybrid, which is used to suppress the local oscillator (LO) intensity noise in both data recovery arm (I arm) and carrier recovery arm (Q arm), is evaluated. Incomplete cancellation of LO intensity noise results from unmatched photodetectors, couplers pathlengths, and non-ideal couplers power splitting ratio. Optimum LO power can be found for the given receiver parameters.     

Image guide couplers used in millimeter wave integrated circuits

The dispersion and coupling characteristics of the coupled image guides are studied by using the odd-even mode principle and effective dielectric constant method. The practical design of the image guide directional couplers is presented. The experiments of 3-dB and 10-dB couplers in ka band show several good features which are very useful to millimeter wave integrated circuits with flat coupling, easy design and fabrication, mechanical stability and low losses.