深孔薄壁件挤压模CAD系统

介绍了利用ActiveXAutomation技术，以VB为开发工具，并采用参数化绘图研究开发的深孔薄壁件挤压模CAD系统。     

Design consideration of photocatalytic oxidation reactors using TiO2-coated foam nickels for degrading indoor gaseous formaldehyde

In the design process of the photocatalytic oxidation (PCO) reactor using TiO₂-coated foam nickels, the optimum of catalyst film thickness, light intensity and flow velocity were considered. A model was developed to study the effect of catalyst film thickness on photocatalytic degradation of formaldehyde by a TiO₂-coated foam nickel at continuous flow mode. In this model, external mass transfer and internal molecule diffusion-reaction were considered. A first-order kinetics equation was used to account for the photocatalytic reaction. Two exponential equations were employed to describe the distribution of light intensities in foam nickels and catalyst films, respectively. Validated with experimental data, the model can be used to predict the optimal thickness of catalyst films. A method for determining appropriate light intensities was proposed and discussed. The appropriate light intensity can be obtained by giving a margin, regarded as an excess coefficient, to the light intensity calculated based on the assumption of complete use of excited electron–hole pairs. The excess coefficient needs to be determined experimentally. In addition, the optimal flow velocity of PCO reactors could be consistent with the required one by changing the windward area of foam nickels. Based on the theoretical analyses, a novel PCO reactor containing 15 parallel-connected cells was designed. Each reaction cell was composed of an UV lamp and a TiO₂-coated tubular foam nickel. The performance of the reactor was tested by degrading gaseous formaldehyde at an indoor concentration level. The results showed that the reactor had low pressure loss and good degradation capability.     

酯化反应偶联渗透汽化膜过程模型(Ⅰ)催化剂的影响

1 INTRODUCTION In former report, the kinetic model for anesterification process coupled by pervaporation wasestablished and the modeling result agreed well withthe experimental result[1].     

压缩真空库中原子系统的偶极压缩特性

运用密度算符方法并结合数值计算,研究了处于压缩真空库中的原子系统的偶极压缩特性,讨论了原子初始态、衰减常数Γ及压缩参量r对原子偶极压缩特性的影响,并给出了相关结论。     

一种基于图像的光学系统测角精度检测方法

测角精度是光学系统的重要技术指标。针对传统的电子经纬仪测角精度检测方法测量数据少、扫描方向单一导致测量结果不准确,提出了一种改进的检测方法。调整电子经纬仪,使电子经纬仪发射的电十字通过光学系统成像在CCD视场中,旋转电子经纬仪以点阵形式,对光学系统各个方向进行扫描,计算机实时采集电十字图像。对采集的电十字图像,通过基于小波变换的变分Retinex算法增强图像对比度,采用OTSU阈值分割背景和目标,采用投影算法及二项式曲线拟合将电十字中心定位到亚像素级。对最终获取的电十字中心点阵数据通过径向基函数进行曲面插值,解算出基于整个CCD像面的测角精度。实验结果表明：该方法的测量精度达到0.1μrad,测得的光学系统测角精度提高了0.01mrad,检测的测角精度更加准确。     

Fluorescence enhancement and cofluorescence in complexes of terbium(III) with trimellitic acid

1. Introduction Rare earth elements have an important function inlife process. The fluorescence enhancement of lan-thanides in aqueous solutions has therefore becomean area of active study in trace-level estimation oflanthanides using spectrofluorimetry [1]. Its possiblemechanism and application as fluorescence probesin biological systems have also attracted attention inrecent years [2]. Generally, fluorescence enhance-ment can be achieved through ligand sensitization.Various ligands have bee…     

Fluorescence enhancement and cofluorescence in complexes of terbium(Ⅲ) with trimellitic acid

The fluorescence of terbium (Ⅲ) was enhanced by about three orders of magnitude in the presence of trimellitic acid (benzene-l, 2, 4-tricarboxylic acid (TLA)) in aqueous solution at pH 6. The fluorescence intensity could be greatly increased when the system of Tb3+-TLA was treated with La3+ (or Gd3+) and TritonX- 100. The addition of La3+ (or Gd3+) enhances the fluorescence of the system by about two orders of magnitude due to cofluorescence, and the TritonX-100 micellar medium plays an important role for stabilization of the system. Both the intermolecular energy transfer mode and intramolecular energy transfer mode are responsible for the mechanism of fluorescence enhancement. In the optimum conditions, the fluorescence intensity is a linear function of Tb3+ concentration in the range of 7.8 × 10-9-3.6 × 10-6 mol/L for the system Tb3+-La3+-TLA and 1.0 × 10-8-4.7 × 10-6 mol/L for the system Tb3+-Gd3+-TLA, and the limits of detection are 4.6 ×10-10 mol/L and 6.0 × 10-10 mol/L, respectively.     

计算机遗传病毒运作模式剖析

遗传病毒是指通过病毒自身的学习机制,反复地经选择、交叉、变异等步骤,进化出的能够适应环境的新病毒.此种病毒种类,较为复杂,且具有较高的变异能力,因此防杀也较为困难.该病毒很难依照固定特征或行为模式来侦测及清除.此类病毒的进化方式,不需创造出完整的病毒,只需是可用的新元件,再通过自身进化出新一代病毒.研究的目的,在于提出遗传病毒的进化模型,供研究人员思考对其的防治.     

适用于Ad Hoc网络的混合认证机制

分析了Ad Hoc网络的特点及其对身份认证机制的安全需求,采用椭圆曲线和对称密钥两种认证体制并结合自证明公钥原理,提出了一种适用于Ad Hoc网络的混合认证机制.该机制中门限方案增强了系统的健壮性,基于自证明公钥的双向认证协议确保了交互节点身份的真实性,刷新认证协议保证了节点身份的持续可信,分布式自证明公钥撤销方案可将恶意节点快速从系统中分离出去.分析结果表明,该认证机制具有较高的安全性,同时对系统存储空间、网络通信量和计算开销的要求都很少,有着较高的效率.