高速铣削过程中铣削力的建模

研究了球头铣刀高速铣削过程铣削力建模与仿真。考虑了作用在前、后刀面上的正压力和摩擦力,建立了高速铣削加工中局部铣削力模型,在上述基础上建立了整体铣削力的模型。通过铣削实验,验证了所建模型的正确性。     

CPV边界积分的对称数值求积法

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　Ｔｈｅｂｏｕｎｄａｒｙｉｎｔｅｇｒａｌｅｑｕａｔｉｏｎｓａｒｉｓｅｉｎｍａｎｙｐｒｏｂｌｅｍｓｏｆｐｈｙｓｉｃｓａｎｄｅｎｇｉｎｅｅｒｉｎｇ .Ｏｎｅｏｆｔｈｅｐｒｉ ｍａｒｙｍａｔｈｅｍａｔｉｃａｌａｎｄｎｕｍｅｒｉｃａｌｄｉｆｆｉｃｕｌｔｉｅｓｏｆｂｏｕｎｄａｒｙｉｎｔｅｇｒａｌｅｑｕａｔｉｏｎａｐｐｅａｒｓｔｏｂｅｔｈｅｔｒｅａｔ ｍｅｎｔｏｆｔｈｅｓｉｎｇｕｌａｒｋｅｒｎｅｌｓ.Ｔｈｅｒｅａｒｅｔｈｒｅｅｄｉｆｆｅｒ ｅｎｔｔｙｐｅｓｏｆｓｉｎｇｕｌａｒｉｔｉｅｓ…     

对称式微波功率传感器的幅度调制测量（英文）

为了减小失配造成的测试误差,在测量调制信号的微波功率时提出了一种直流校正方法.在传感器左端输入微波功率,右端输入直流功率,微波功率存在的寄生损耗和电磁耦合造成了失配误差,而直流功率不存在失配误差,所以通过右端输入的直流功率可以校正左端微波功率的失配误差.测试了在不同调制率和调制深度的校正因子.测试结果表明,载波频率是造成幅度调制测试误差的主要因素,校正后载波频率和调制率对输出电压的影响很小,频率响应在20GHz范围内变得相对平滑,而且灵敏度平均提高了大约0.12mV/dBm.因此,该直流校正方法对于终端式微波功率传感器具有一定的参考意义.     

加工中心MTBF值的点估计与区间估计

应用基于截尾数据的似然函数理论和Weibull分布下的似然比方法,对加工中心有替换定时截尾试验数据分别进行了加工中心平均故障时间间隔(MTBF)值的点估计与区间估计。根据似然函数的重要引理,用迭代方法进行了Weibull模型两个参数的区间估计,并进行了MTBF值的区间估计。本研究解决了加工中心可靠性评估工作中的难题。     

Decomposition mechanism of chloramphenicol under electron beam irradiation

The purpose of this study was to evaluate the potential of electron beam to decompose chloramphenicol （CAP） in aqueous solutions. At the absorbed dose of 15 kGy, the decomposition rate of CAP was 95.24%. The degradation of CAP under electron beam irradiation followed pseudo-first-order kinetics. Redox reactions of CAP aqueous solutions with hydroxyl radicals （.OH）, hydrated electrons （eaq） and hydrated atoms （·H） were studied. The increase of the additives would result in the decrease of the degradation efficiency. The concentration of Cl- and NO3- in aqueous solution increased after electron beam irradiation. On the basis of the experimental results, a photocatalytic mechanism was discussed. The rate constant for reactions of .OH and CAP was 9.36×10^7 L/（mol.s） and for reaction of eaq and CAP was 7.33×10^7 L/（mol.s）..OH was supposed to play the key role in the radiation system of aqueous solution. Other free radicals like eaq and .H could also initiate the degradation.     

C2v群对称性实例分析

本文通过对H2O分子结构特点及其几何对称变换问题的分析,阐明群论在分子结构与变换中的应用,通过实例对比,说明对称元素对对称性的影响,并希望据此探讨分子结构的稳定性与其对称性的关系。     

Calculation of Expected Shortfall for Measuring Risk and Its Applications

Expected shortfall(ES) is a new method to measure market risk. In this paper, an example was presented to illustrate that the ES is coherent but value-at-risk(VaR) is not coherent. Three formulas for calculating the ES based on historical simulation method, normal method and GARCH method were derived. Further, a numerical experiment on optimizing portfolio using ES was provided.     

SCORM运行时环境支持流式视频点播关键技术研究

SCORM运行时环境支持流式视频点播是丰富SCORM课件媒体展现能力的关键技术,但在当前成品系统中鲜有实现。文章从分析原因入手,通过解决造成此情况的根本问题,提出了基于Flash Video技术SCORM运行时环境支持流式视频点播实现方案,较好实现了SCORM运行时环境对流式视频点播的支持。文中还介绍了实现方案的具体优势与局限性。是SCORM运行时环境对流式视频点播的支持相关技术的较全面介绍。     

Shape memory behavior of SMPU knitted fabric

A preliminary investigation of shape memory (SM) effects of SMPU (shape memory polyurethane) knitting fabric is presented in this paper. Three SMPU knitted fabrics series with different content of SMPU fibers: 100% SMPU, 50% SMPU and 50% cotton, 16% SMPU and 84% cotton are designed and manufactured in our lab. Their shape memory behaviors at different temperatures are characterized in terms of bagging. Our experimental results showed that shape memory effect can be improved with increasing content of SMPU fibers. A comparison between Lycra and SMPU knitted fabrics was also made to validate the shape memory effects of SMPU knitted fabrics.     

对CAD技术发展前景的探讨

本文概述了CAD(Computer Aided Design)技术的基本概念及其应用领域的发展状况,认为CAD技术存在缺陷和不足的主要原因是由于缺乏知识表示和推理机制。本文通过阐述专家系统技术的定义、组成及其领域,预示了CAD技术今后的发展方向和趋势。我们分析了我国专家系统技术和CAD技术目前的应用状况,指出在CAD技术中采用专家系统技术不仅是必要的而且是可能的,目的是为了引起人们对专家系统技术的足够重视。