Modification to the Fringe Component of Diffraction Coefficient in TD-EEC Method

A modified formulation for fringe component of diffraction coefficient is implemented to TD-EEC method. An example of diffraction by perfectly conducting plate is used to illustrate our scheme. Comparing with the FDTD results we observe that the improved expression for fringe component is more accurate than that of Michaeli's formulation. This high frequency time domain technique is available for treating the bistatic scattering problems for millimeter waves.     

静磁场中的互作用能

讨论了在激发磁场的电流保持不变时和束缚磁荷作为磁场的不变时，两种情况下磁场的相互作用能。结果与静电场类似，两种情况的互作用能中都含有相互磁化，致使物体磁化状态改变作的功。     

Phenol biosensor based on electrochemically controlled integration of tyrosinase in a redox polymer

An amperometric biosensor for the detection of phenolic compounds was developed based on the immobilization of tyrosinase within an Os-complex functionalized electrodeposition polymer. Integration of tyrosinase within the redox polymer assures efficient catechol recycling between the enzyme and the polymer bound redox sites. The non-manual immobilization procedure improves the reproducibility of fabrication process, greatly reduces the desorption of the enzyme from the immobilization layer, and, most importantly prevents fast inactivation of the enzyme by its substrate due to fast redox cycling. A two-layer sensor architecture was developed involving ascorbic acid oxidase entrapped within an electrodeposition polymer in a second layer on top of the redox polymer/tyrosinase layer. Using this sensor architecture it was possible to eliminate the current interference arising from direct ascorbate oxidation up to a concentration of 630 μM ascorbic acid. The effects of the polymer thickness, the enzyme/polymer ratio, and the applied potential were evaluated with respect to optimal sensor properties. The sensitivity of the optimized sensors for catechol was 6.1 nA μM⁻¹ with a detection limit of 10 nM, and for phenol 0.15 nA μM⁻¹ with a detection limit of 100 nM.     

因特网防御DoS攻击技术评述Ⅰ--攻击分类与特征·包过滤·攻击检测与防御

概述了因特网上DoS攻击的相应分类及基本特征，评述了包过滤、攻击检测及防御技术的最新成果．前一部分介绍了入口过滤、基于路由的过滤网和有效源地址强制协议．后一方面主要讨论了适合于检测攻击包的技术，介绍了新近提出的频谱分析方法和泛滥检测系统．简要评述了已有的防御SYN泛滥攻击的技术措施，介绍了Cisco的TCP拦截技术，提出了改进策略．     

Synthesis of perfluorinated functionalized, branched ethers

We wish to report synthesis of perfluorinated functionalized, branched ethers from their hydrocarbon analogues by direct fluorination. Yields up to 90%, with high purities, have been obtained at ambient temperature and pressure. This technique will likely develop into a new general method for producing perfluorinated, hyperbranched and dendritic polymers.     

Possible triggering of solar activity to big earthquakes (Ms ≥ 8) in faults with near west-east strike in China

A big earthquake (Ms = 8.1) occurred at western Kunlun Mts gap on November 14, 2001. It is the biggest earthquake in China in the past 50 years and the only one with a magnitude bigger than 8 in China after Dangxiong Earthquake (M = 8) in Tibet in 1951. The big earthquake has drawn wide attention of scientists in seismological, geophysical, geological and astro-geodynamic circles. Scientists are interested in the occurrence regularity of the very big earthquakes and try to find out the fac…     

无电极电光电场传感器灵敏度提高的研究

从提高灵敏度角度出发,理论上分析了无电极电光电场传感器电极长度与灵敏度和带宽的关系.通过比较不同结构的传输函数,验证平衡检测方式的可行性,最后选取使用平衡检测的三端口结构作为实验器件结构,从而为器件制作的可行性方案从理论上作了验证.     

基于分层光学扫描的三维数字化测量技术

采用切削分层光扫描测量与计算机数据信息合成相结合的方法，有效地解决了具有复杂内外腔结构零件的三维数字化测量。该方法比传统三维测量速度快、自动化程度高，能同时准确测量零件内外腔表面，零件边缘测量误差可控制在CCD两个像素内。利用获取的铝合金精密小箱体三维数据，在计算机上重构了零件的三维模型，并用RP技术制造出了零件物理原形。     

激光水下偏振特性用于目标图像探测

利用激光水下偏振特性获得偏振差分图像(PDI),并运用PDI技术,从理论和实验上对水下目标探测进行了研究.介绍了PDI基本概念和实验系统原理,然后比较分析了不同条件下普通图像与PDI在辨别目标距离及其纹理上的差别和PDI中背景偏振光的影响,得出利用目标和背景偏振光的差异区分二者,从而提高探测距离的结论,并取得了较好的效果.在此基础上提出了通过处理有关PDI偏振参量来进一步辨别目标与背景的设想.     

On the Solution of Discontinuous IVPs by Adaptive Runge–Kutta Codes

In this paper an automatic technique for handling discontinuous IVPs when they are solved by means of adaptive Runge–Kutta codes is proposed. This technique detects, accurately locates and passes the discontinuities in the solution of IVPs by using the information generated by the code along the numerical integration together with a continuous interpolant of the discrete solution. A remarkable feature is that it does not require additional information on the location of the discontinuities. Some numerical experiments are presented to illustrate the reliability and efficiency of the proposed algorithms.