基于VST的电力系统电压稳定分岔分析

概述了非线性动力系统分岔理论,介绍了基于MATLAB的电压稳定分析工具箱(Voltage Stability Tool-box,VST)。运用VST对IEEE-5节点系统在几种不同控制参数变化模式下进行了静态和动态分岔点的搜索,获得了比较满意的结果,验证了非线性的分岔理论在电压稳定分析中的相关结论。     

基于虚拟化技术的信息系统安全防护框架研究

关键信息系统的安全防护问题一直以来都是研究热点。围绕数据安全和恶意代码攻击等关键安全问题,以虚拟机监视器作为安全防护立足点,充分利用虚拟机监视器的拦截、隔离、I/O数据加解密等机制,构建了一种新的信息系统安全防护构架,详细阐述了安全防护框架的工作原理以及典型安全服务的构建方法。     

基于PID分段式温度控制系统的设计与实现

通过对PID算法及控温方式的改进,提高温控系统的控温精度,采用分段温控技术,使其具有稳定性好和超调小的特点。     

Jointly Part-of-Speech Tagging and Semantic Role Labeling Using Auxiliary Deep Neural Network Model

Previous studies have shown that there is potential semantic dependency between part-of-speech and semantic roles. At the same time, the predicate-argument structure in a sentence is important information for semantic role labeling task. In this work, we introduce the auxiliary deep neural network model, which models semantic dependency between part-of-speech and semantic roles and incorporates the information of predicate-argument into semantic role labeling. Based on the framework of joint learning, part-of-speech tagging is used as an auxiliary task to improve the result of the semantic role labeling. In addition, we introduce the argument recognition layer in the training process of the main task-semantic role labeling, so the argument-related structural information selected by the predicate through the attention mechanism is used to assist the main task. Because the model makes full use of the semantic dependency between part-of-speech and semantic roles and the structural information of predicateargument, our model achieved the F1 value of 89.0% on the WSJ test set of CoNLL2005, which is superior to existing state-of-the-art model about 0.8%.     

Effect of refrigerant flow direction and throttle opening in RAC unit using micro-channel evaporator

Experimental comparisons are made on the performance of a room air conditioner using micro-channel evaporator with the refrigerant flowing in the Upward Flow mode (UF mode, meaning refrigerant flowing upward from the bottom) and Downward Flow mode (DF mode, meaning refrigerant flowing downward from the top). Test results show that UF mode develops a superior refrigerant distribution in the micro-channels to what DF mode does. This is then illustrated by the infrared thermographs at the nominal operating condition. Subsequently, the effect of the width of throttle opening on the sample unit performance is investigated experimentally in the micro-channel evaporator adopting the UF mode. Measurement and calculation results of pressure difference between evaporator inlet and outlet, mean temperature of the evaporator surface, cooling capacity, input power and EER show that the tested unit operates with the best performance with the refrigerant pressure of 993.61 kPa at the inlet of micro-channel evaporator. Infrared thermographs of the working evaporator verify this conclusion.     

基于全局最近邻的离群点检测算法

针对全局最近邻离群点检测算法的效率问题,为了能够在数据集中快速准确地检测离群点,运用属性约简技术,将离群点的搜索简约到较小的最具代表性的属性子空间中进行,从而有效降低属性空间搜索的复杂度。在此基础上,通过计算基于近邻的加权离群因子实现离群点的检测并提出了相应的算法。实验表明,该离群点算法具有较好的适应性和有效性。     

Synthesis of a boron-containing conducting polymer from the anodic oxidation of Tris(pyrrolyl)borane

The electrochemical oxidation of Tris(N-pyrrolyl)borane (1) in THF yielded a conducting polymer film with an electron conductivity of ca. 7×10⁻⁴ S cm⁻¹. The coulometric measurements indicated that the three pyrrolyl units were not totally coupled during the electropolymerization reaction. From further UV–VIS and FT-IR spectroscopy data, a structure of poly(1) was then proposed.     

Heat recovery from Diesel engines: A thermodynamic comparison between Kalina and ORC cycles

In the context of heat recovery for electric power generation, Kalina cycle (a thermodynamic cycle using as working fluid a mixture of water and ammonia) and Organic Rankine Cycle (ORC) represent two different eligible technologies. In this work a comparison between the thermodynamic performances of Kalina cycle and an ORC cycle, using hexamethyldisiloxane as working fluid, was conducted for the case of heat recovery from two Diesel engines, each one with an electrical power of 8900 kWe. The maximum net electric power that can be produced exploiting the heat source constituted by the exhaust gases mass flow (35 kg/s for both engines, at 346 °C) was calculated for the two thermodynamic cycles. Owing to the relatively low useful power, for the Kalina cycle a relatively simple plant layout was assumed. Supposing reasonable design parameters and a logarithmic mean temperature difference in the heat recovery exchanger of 50 °C, a net electric power of 1615 kW and of 1603 kW respectively for the Kalina and for the ORC cycle was calculated.Although the obtained useful powers are actually equal in value, the Kalina cycle requires a very high maximum pressure in order to obtain high thermodynamic performances (in our case, 100 bar against about 10 bar for the ORC cycle). So, the adoption of Kalina cycle, at least for low power level and medium–high temperature thermal sources, seems not to be justified because the gain in performance with respect to a properly optimized ORC is very small and must be obtained with a complicated plant scheme, large surface heat exchangers and particular high pressure resistant and no-corrosion materials.     

Ni-P化学镀层对工件表面粗糙度的影响

表面粗糙度是影响工件性能的一个重要因素,适当减少表面粗糙度值可以改善工件表面的机械特性,为了掌握化学镀后工件表面粗糙度值的变化规律,在同一种Ni-P化学镀镀液中,对经测量具有不同表面粗糙度值的工件,镀上相同厚度的镀层,再测量工件表面粗糙度值,对比两次测量数据,结果发现化学镀后工件表面粗糙度值普遍减小,结合镀层表面微观形状图分析得知,在微观表面的波峰和波谷处存在沉积发生面的面积变化是工件表面粗糙度值普遍减小的原因,再经数学计算得出,表面粗糙度值的减小量随工件原表面粗糙度值增大而增大,减小幅度约为工件原表面粗糙度值的11%.     

基于MapInfo的军事区域管网地理信息系统

提出了军事区域给排水管网地理信息系统（GIS）设计模式，以MapInfo6．0为主要GIS平台，采用MapBasic和第三方语言（Visual C＋＋）对系统进行开发，重点阐述了系统功能及关键技术的实现方法。该系统的建立对军事区域相关部门提高管理水平和工作效率具有重要作用，有较强的实用价值。