A recursive-faulting model of distributed damage in confined brittle materials

We develop a model of distributed damage in brittle materials deforming in triaxial compression based on the explicit construction of special microstructures obtained by recursive faulting. The model aims to predict the effective or macroscopic behavior of the material from its elastic and fracture properties; and to predict the microstructures underlying the microscopic behavior. The model accounts for the elasticity of the matrix, fault nucleation and the cohesive and frictional behavior of the faults. We analyze the resulting quasistatic boundary value problem and determine the relaxation of the potential energy, which describes the macroscopic material behavior averaged over all possible fine-scale structures. Finally, we present numerical calculations of the dynamic multi-axial compression experiments on sintered aluminum nitride of Chen and Ravichandran [1994. Dynamic compressive behavior of ceramics under lateral confinement. J. Phys. IV 4, 177-182; 1996a. Static and dynamic compressive behavior of aluminum nitride under moderate confinement. J. Am. Soc. Ceramics 79(3), 579-584; 1996b. An experimental technique for imposing dynamic multiaxial compression with mechanical confinement. Exp. Mech. 36(2), 155-158; 2000. Failure mode transition in ceramics under dynamic multiaxial compression. Int. J. Fracture 101, 141-159]. The model correctly predicts the general trends regarding the observed damage patterns; and the brittle-to-ductile transition resulting under increasing confinement.     

Mafia和Hfss对等梯度加速结构耦合器的数值模拟与比较

提出的数值模拟过程是关于直线加速器加速结构耦合器的设计的。Mafia程序和Hfss程序分别被用来模拟一截S—Band的三腔等梯度加速结构,其两端分别为输入耦合器和输出耦合器。通过Mafia程序和Hfss程序模拟了该结构的传输特性,发现两者的模拟结果能很好吻合。     

一个检测超流的早期淘汰算法

超流是网络中具有大量不同宿IP/源IP链接的源IP/宿IP.实时检测出高速网络（OC48、OC192等）中的超流对网络安全具有非常重要的意义.近年来已经有论文提出了不同超流检测算法,但是这些算法都没有考虑控制测量过程中超流缓存空间的大小.论文在超流检测过程中增加了早期淘汰功能,将超流缓存中链接数较少的记录提前淘汰,以便腾出空间用于存储新检测到的IP记录,实现对超流缓存资源的控制.论文最后还使用实际网络日志数据对算法进行验证,实验表明：早期淘汰算法可以使系统以更少的内存空间和测量资源检测超流信息.     

TKSS—C型信号与系统实验箱的低通滤波器分析

对TKSS-C型信号与系统实验箱的低通滤波器实验模块进行了s平面几何分析，并利用MATLAB7．01中的Power Systems Blockset对其进行了仿真．     

虚拟技术在实验教学中的应用

介绍了虚拟技术在实验教学改革中的作用与意义，探讨了电子信息系统实验教学改革的新思路与实现措施，并总结了实验教学改革的初步成果．     

Monte Carlo Simulation of Electron Transport and X-Ray Generation. II. Radiative Processes and Examples in Electron Probe Microanalysis

Theoretical models for Monte Carlo simulation of radiative processes, i.e. bremsstrahlung and characteristic x-ray emission, are presented. Possible strategies for simulating electron transport are briefly described. For mechanisms involving energy loss and angular deflections, difficulties for strict implementation of accurate numerical differential cross sections still remain due to the strong correlations between these variables. Practical solutions for the case of inelastic collisions and bremsstrahlung emission are described. Comparisons of simulation results with experimental data for several problems of interest in electron probe microanalysis are presented.     

Performance of noise barriers with various edge shapes and acoustical conditions

The performances of barriers having different shapes and surface conditions were tested using the boundary element method in a well-controlled environment. The heights and widths of the barriers were standardized and the insertion losses for six receiver positions were averaged and compared. Figures displaying the results allow for straightforward barrier performance estimation. It was shown that absorbing and soft edges significantly improve the efficiency of the barrier, but configuration modifications provide only a slight improvement. The soft T-shaped barrier produces the highest performance. A 3 m high T-shaped barrier provides the same performance as a 10 m high plain barrier. The spectral efficiency was also investigated. The insertion loss spectra for the absorbing and the soft barriers exhibit a similar shape, but the rigid barrier differs from these two.     

Simulation of polarization effects in AlGaN/GaN heterojunction

Because of their large band-gap, large high-field electron velocity, large breakdownfield, and large thermal conductivity, GaN and its heterojunction with AlGaN and InGaNhave foreseeable potential in the applications of high-power/temperature electronics, andoptoelectronic devices operative in UV and visible wavelength. Polarization inducedelectric field can reach the magnitude of ~MV/cm[1,2]. For AlGaN/GaN based FETs theconcentration of sheet carrier induced by polarization in the cha…     

群速度和相速度的微机模拟

本文介绍了作者开发的群速度和相速度微机模拟软件的程序设计和实现．该软件做为演示实验已经取得了良好的效果．     

佛山市城市公共交通发展策略

通过对佛山市公共交通客流和公共交通设施现状的调查，掌握了居民出行规律和客运交通特征指标．采用定性和定量相结合的方法，综合评价了公共交通现状的水平．在分析佛山市未来社会经济、城市发展基本特征的基础上，根据客流分布特点、发展态势及客流交通的生成变化特征，采用经验加模型系统方法，科学地预测发展需求．结合佛山市的实际，分析了公共交通的优劣势，确定了优先发展公共交通的方针与目标．对公共交通政策进行了研究，并提出确保实施公共交通目标的对策和措施