探针馈电圆柱共形微带天线阻抗特性的FDTD法分析

将圆柱坐标系下非分裂式理想匹配层吸收边界条件(UPML)引入到圆柱共形微带天线的全波分析中，并给出了其中的场量迭代方程，明显地减小了计算空间，简化了编程；提出了圆柱坐标系下考虑有限尺寸探针半径的新算法，使得计算结果更加精确；应用GPOF方法预估了时域晚时响应，使计算时间减少了70％～90％。本文给出的模型能够对任意多层圆柱共形结构的微带天线进行计算，因此对此类天线的CAD设计具有实际意义。     

具有底水边界的水平井压力不稳态特征分析及认识

根据水平井三维渗流特征，在底水油藏情形仍假定顶面为不渗透隔层所封闭，底部则是恒压边界，水平井渗流表现为早期径向流以及稳定流动期，由此进行常规试井分析。以TKxxDH井为例，通过水平井的静压、压恢试井资料结果的对比分析，阐述了不稳定试井资料的应用，为此类油藏油井模型的选择及效果评价提供了可借签的经验。     

有植被的河道水流紊动特性模型试验研究

通过物理模型试验,研究了有植被的河道水流紊动特性.试验结果表明,在复式断面河道滩地种植柔性植被后,滩地糙率增大,水流紊动更为剧烈,河道水流紊动强度峰值由原先的滩槽交界区转移到滩地区.滩地的水流紊动强度沿程递减;滩槽交界区的水流紊动强度沿程不断增大;主槽的水流紊动强度主要与床面糙率有关,滩地植被影响了滩地水流的归槽时间,使主槽水流流速沿程增大.     

A comparison of transformation methods for evaluating two‐dimensional weakly singular integrals

Accurate numerical evaluation of integrals arising in the boundary element method is fundamental to achieving useful results via this solution technique. In this paper, a number of techniques are considered to evaluate the weakly singular integrals which arise in the solution of Laplace's equation in three dimensions and Poisson's equation in two dimensions. Both are two‐dimensional weakly singular integrals and are evaluated using (in a product fashion) methods which have recently been used for evaluating one‐dimensional weakly singular integrals arising in the boundary element method. The methods used are based on various polynomial transformations of conventional Gaussian quadrature points where the transformation polynomial has zero Jacobian at the singular point. Methods which split the region of integration into sub‐regions are considered as well as non‐splitting methods. In particular, the newly introduced and highly accurate generalized composite subtraction of singularity and non‐linear transformation approach (GSSNT) is applied to various two‐dimensional weakly singular integrals. A study of the different methods reveals complex relationships between transformation orders, position of the singular point, integration kernel and basis function. It is concluded that the GSSNT method gives the best overall results for the two‐dimensional weakly singular integrals studied. Copyright © 2002 John Wiley & Sons, Ltd.     

多业务移动通信系统中的呼叫接入控制

在多业务无线移动通信系统的呼叫接入控制中,不仅要考虑业务之间的优先级,同时也必须考虑切换呼叫的优先级。本文结合可移动边界算法和保护信道策略,提出了一种有效的多业务呼叫接入控制算法。为了方便地分析方案的性能,设计了一个二维的Markov链对方案的性能进行理论上的分析。通过数值分析结果表明,提出的算法同时保证了两种优先级,并提高了系统的性能。1     

摩擦换向抽油机悬点运动分析计算

摩擦换向抽油机采用开关磁阻电动机或变频调速电动机,其特点是可以频繁双向旋转,带动摩擦轮正反转,实现光杆的上行下行。该抽油机运动特点与游梁式抽油机运动特点有较大区别,文章分析了摩擦换向抽油机的运动特点,给出了该机悬点位移、速度、加速度的计算方法。     

用于磁场测量的高精度500A/30V零压开关直流稳流电源

研制了一种带有无源辅助网络的全桥移相脉宽调制零压开关(FB PSPWMZVS)高精度磁铁稳流电源,并在电磁铁磁场测量中得到应用,其电流稳定度在8h内优于±1×10-4。     

N-油酰基肌氨酸钠对除盐水缓蚀性能的探讨

对N-油酰基肌氨酸钠单体的缓蚀性能以及与常用除盐水缓蚀剂的协同作用作了探讨,发现在一定浓度下,单体对经过加氨调节后的高温除盐水(氨后除盐水)有良好的缓蚀作用,且与大多数除盐水缓蚀剂有良好的协同效应。在此基础上研制了一种复合药剂,并对其缓蚀、阻蚀性能作了研究。动电位极化曲线扫描图谱表明,该复合药剂属于抑制阳极腐蚀的阳极型缓蚀剂,其适用的水质条件为[Cl~-+SO_4~(2-)]不超过50 mg／L,pH不低于8.0；与阻垢剂复配,可以适用于含Ca~(2+)不超过45 mg／L的水质条件。     

变速鱼雷推进器动态模型理论研究

传统鱼雷推进器静态模型已无法满足变速鱼雷的建模需要，为了解决这一问题，在国内外学者研究的基础上，运用流体动力学方法，建立了鱼雷推进器比较精确的动态模型。该模型是以推进器来流速度和螺旋桨转速为状态变量，以电机施加转矩为输入，螺旋桨推力和转矩为输出的。     

An Exploratory Study of E-Business Success Factors

E-business success factors are Important for traditional enterprises to implement e-business. This topic is attracting more and more researchers to study. This paper makes an exploratory study on the factors influencing e-business success. Firstly, based on the literature review, 52 factors are suggested. Secondly, two rounds of survey with Delphi method are conducted. Qualitative and quantitative analysis are used to identify 57 factors. This is the foundation of empirical study.