两类平面图的指数集

完全确定了极大可平面图与极大外可平面图的指数集。     

有载树型电力网单一负载故障的诊断方法

求文提出一种有载树型电力网单一负载故障的诊断方法，该方法的特声、是诊断所需要的端口变量易于测量，测后计算量较小，适用于多分支的有载树型电力网的单一负载故障诊断。经计算机仿真，证明了所提诊断方法是有效的。     

Transformations and dynamic linear models

The dynamic linear model (DLM) with additive Gaussian errors provides a useful statistical tool that is easily implemented because of the simplicity of updating a normal model that has a natural conjugate prior. If the model is not linear or if it does not have additive Gaussian errors, then numerical methods are usually required to update the distributions of the unknown parameters. If the dimension of the parameter space is small, numerical methods are feasible. However, as the number of unknown parameters increases, the numerial methods rapidly grow in complexity and cost. This article addresses the situation where a state dependent transformation of the observations follows the DLM, but a priori the appropriate transformation is not known. The Box-Cox family, which is indexed by a single parameter, illustrates the methodology. A prior distribution is constructed over a grid of points for the transformation parameter. For each value of the grid the relevant parameter esitmates and forecasts are obtained for the transformed series. These quantities are then integrated by the current distribution of the transformation parameter. When a new observation becomes available, parallel Kalman filters are used to update the distributions of the unknown parameters and to compute the likelihood of the transformation parameter at each grid point. The distribution of the transformation parameter is then updated.     

实验用互补对称功率放大电路的设计与测试

通过对原有的典型互补对称功放电路参数的调整和改动,及对实验步骤和测试方法的优化,从而提高了电路的可操作性、可测试性和实用性,并减少了实验操作时间。     

Matlab-Simulink在交流调速系统仿真中的应用

介绍了一种用于交流调速系统的仿真软件——Matlab-Simulink，并结合其中的Power System Blockset对其在交流调速系统仿真中的应用进行了说明，详细介绍了仿真模型的建立过程。     

用“礼貌原则”理论探讨中日话题选择的问题——以燕山大学日语专业为例

以燕山大学日语专业四年级学生为研究对象,就同届同一性别大学生分别使用日语和汉语在初次见面谈话中所选话题问题进行了考察.从整体上看,即使会话时使用的语言不同但是所选的话题项目大体相同.使用日语会话时10组中有4组谈到恋爱方面的话题,而使用汉语会话时没有出现相关话题.针对这一现象,结合对学生的追踪调查,运用Brown ＆amp;Levinson（1987）礼貌原则进行分析说明.     

Polarization behavior of microbial fuel cells under stack operation

The polarization behavior of microbial fuel cells(MFCs)was evaluated under different stack operation modes,including series,parallel,series–parallel,and parallel–series.During the stack operation,voltages of individual MFCs,subunit stacks,and overall stacks were recorded as a function of the current.Meanwhile,the potentials of individual MFCs’anode and cathode were also determined via Ag/AgCl electrodes to study the change in potentials under stack operations.The results demonstrated that the MFCs with relatively low ability to generate current were easier to suffer polarity reversal in the series stack,which was confirmed in the series subunit of the series–parallel stack.MFCs with high electroactivity would be enhanced to generate larger maximum power;however,MFCs with low electroactivity outputted smaller maximum power in a parallel stack.The changes in individual MFCs’behavior under stack operation mode were determined primarily caused by the influences on the behavior of the anode.Results of the present study provide valuable information for optimization of stack operation of MFCs.     

浅谈供配电系统的可靠性分析方法

本文对我国的电力系统可靠性的重要性进行简要的阐述,指出我国在可靠性的现状与国外的差距,对传统方法和改进的方法进行综述,通过比较之间的优缺点,为我国今后电力系统可靠性的发展提供理论支持。     

二维米堆模型中的自组织临界行为

对具有随机倒塌过程的二维米堆模型的临界行为进行了数值模拟研究.系统经一个暂态过程后达到一个临界态,雪崩大小的概率统计分布服从"幂次"规律,其临界雪崩指数为τs=1.26±0.01.τt=1.42±0.02和τa=1.30±0.01.它们和BTW沙堆模型的雪崩指数是不同的,所以这个模型和BTW沙堆模型属于不同的普适类.