Scaling considerations for modelling the in situ vitrification process

Thermal-electric field interactions occur in many areas of engineering. An example is the in situ vitrification process, a relatively new technology for remediating hazardous wastes. Mathematical and physical modelling of this process requires knowledge of the similarity constraints involving thermal- electric fields. This paper addresses this issue and derives the scaling relationships for modelling the remediation process from fundamental principles. Requirements for maintaining temperature and electric potential field similarity between the model and the prototype are determined as well as requirements for maintaining similarity in off-gas generation rates. A scaling rationale for designing reduced scale experiments is presented, and the results are assessed numerically.     

On Local Coefficients for Non-generic Representations of Some Classical Groups

This paper is concerned with representations of split orthogonal and quasi-split unitary groups over a nonarchimedean local field which are not generic, but which support a unique model of a different kind, the generalized Bessel model. The properties of the Bessel models under induction are studied, and an analogue of Rodier's theorem concerning the induction of Whittaker models is proved for Bessel models which are minimal in a suitable sense. The holomorphicity in the induction parameter of the Bessel functional is established. Local coefficients are defined for each irreducible supercuspidal representation which carries a Bessel functional and also for a certain component of each representation parabolically induced from such a supercuspidal. The local coefficients are related to the Plancherel measures, and their zeroes are shown to be among the poles of the standard intertwining operators.     

金融危机下Fama-French多因子模型在中国债券市场的应用

利用近3年的中国债券市场数据,建立了Fama-French多因子模型,并利用多元回归方法进行了比较分析.结果表明,TERM-DEF两因子模型有着较好的适用性,但存在进一步改进的空间.     

一类数列极限的概率求法

通过建立适当的随机模型,应用概率方法可以确定一类具有复杂结构的数列的极限,本文通过举例说明这种方法的运用     

具有椭球等高分布误差的半参数回归模型参数的Bayes估计

本文给出了具有椭球等高分布误差的半参数回归模型中参数的Ｂａｙｅｓ估计．     

基于有限元仿真的东风11型救援小车支撑块结构优化

对东风11型救援小车支撑件进行了有限元分析．通过有限元计算。详细分析了有效应力分布情况；找出了应力集中较大的区域．并分析了其主要原因；观察了应力值最大区域并提出了改善应力集中的方法和措施。从而达到了结构优化的目的．     

汉字识别的加工模型

通过文献分析,概述了认知心理学关于汉字识别过程及其加工机制研究的几种主要的加工模型,即经成分识别模型、多层次交互激活模型、连接主义模型、合体汉字字形识别模型和汉字识别的多层次格式塔双向加工模型.     

SARS传播的数学模型的建立与分析

建立一个SARS传播的实用的、可求解的改进SIR模型,并用差分方法进行求解。利用北京SARS病例数据对模型验证表明,拟合曲线与实际数据基本吻合,平均相对绝对值误差为0．0153。对隔离时机的提前或延后造成的后果进行数值分析,可得出最终确诊病例累计数与隔离时机的延长或提前呈指数增长或下降的结论。     

基于系统调用的实时IDS方案

给出一种基于进程系统调用的实时IDS方案.该方案选择网络服务进程(特权进程)作为系统的代表进行监测,使用隐马尔可夫模型(HMM)对系统行为进行模拟和测试,使用实时P(O|λ)值和近期对“某些重要文件”的读、写频率这两个条件作为判断系统是否遭受入侵的标准.实验和分析表明,该方案有较高的预报准确率和较小的时间开销.     

砂土地基锚板基础抗拔承载力PFC数值分析

在模型试验的基础上,采用PFC离散单元法对条形锚板基础在中密砂土地基中的抗拔性能进行了数值分析。数值模拟采用簇颗粒单元来模拟砂粒的不规则形状,颗粒级配根据模型试验福建标准砂的级配按照相似级配法生成,细观参数根据数值双轴试验确定。水平锚板数值模拟结果与模型试验结果基本一致。与模型试验结果相比,颗粒流数值模拟能得到颗粒间接触力链的分布及其演化规律,能从细观角度来探明宏观抗拔承载力特性的演化机理。在此基础上对倾斜锚板上拔过程进行了模拟,分析了锚板前后砂粒的运动趋势以及接触力链的演化规律,并与已有承载力结果进行了对比分析。