IEC61850操作语义形式化描述的Petri网方法及其实现

通过对IEC61850标准中变电站配置语言(SubstationConfigurationLanguage,SCL)的XMLSchema(ExtensibleMarkupLanguageSchema)定义和声明内容的研究发现,统一建模语言(UnifiedModelingLanguage,UML)状态机的语义表达能力存在明显的局限性,它与XML结合无法精确描述具有逻辑时序要求的模块语义,造成在IEC61850完备的语义信息模型基础上建立的ACSI(AbstractCommunicationServiceInterface)的XML描述不完备,极大地影响系统的互操作性。文章应用Petrinet建立的IEC61850控制模块具有明确的语义模型,基于XML的Petrinet形式化描述不仅实现了语义信息模型的完备描述,也完善和强化了SCL的XMLSchema描述操作语义的能力,有效保证了系统的互操作性和一致性。     

无功补偿在高耗能工业区的应用

针对如何解决高耗能工业区电网系统缺无功问题,提出了切实可行的方案,并通过实例,对方案的效益进行了评价。     

含硼微合金钢的静态及动态软化行为

运用gleeble-1500热模拟试验机November对含硼微合金钢进行了单、双道次压缩模拟,并通过非线性回归分析得到了静态与动态软化百分比(X)与变形温度(T)、变形程度(ε)、变形速率(ε·)、原始晶粒尺寸(d0)、道次间隔时间(t)之间的关系。     

多级旋转式倒立摆的建模与分析

运用刚体的动力学知识对多级旋转式倒立摆系统进行了动力学分析,归纳其规律性,并推导出旋臂及各级摆杆的运动微分方程,从而获得任意级旋转式倒立摆的非线性数学模型。文中还对旋转式倒立摆系统进行了能控性分析。最后利用MATLAB对一级、二级旋转式倒立摆的控制进行了仿真,并得到较好的仿真结果。     

软件抗干扰技术在工控系统中的应用

在工业控制领域中各种干扰信号很多。阐述了如何通过软件技术来提高单片机系统的稳定性。     

活齿端面谐波齿轮啮合状态的几何模型

活齿端面谐波齿轮是综合现有的谐波齿轮传动和活齿传动的优点而发明的一种新型传动装置．可以在保留现有谐波齿轮传动所有优点的基础上．大幅度地提高所传递的功率。建立了描写活齿端面谐波齿轮啮合状态的几何模型．并利用该几何模型推导出了活齿端面谐波齿轮实现连续传动的条件。     

Water vapor transport in liquid crystalline and non-liquid crystalline epoxies

This paper presents a comparison of moisture permeation in liquid crystalline and non-liquid crystalline epoxy systems. The permeability is obtained using a dynamic method. It is found that diffusion in both epoxy systems is Fickian. The liquid crystalline epoxy network exhibits higher barrier properties to moisture transport than the conventional epoxy network. The efficient chain packing of the smectic mesophase of the liquid crystalline epoxy is the main factor for this difference. The stoichiometry has a large effect on the moisture permeation. The diffusion coefficient decreases monotonically with increasing amine/epoxide functional ratio. The permeability (P) and solubility coefficient (S) reach a minimum for a functional ratio of one. The results are described on the basis of hydrogen bonding of water to the epoxy network and the two phase morphology of cured epoxies.     

Effect of synthesis temperature on density and microstructure of MgB2 superconductor at ambient pressure

The experimental thermodynamic of MgB₂ synthesis process and phase compositions have been investigated by diffraction thermal analysis (DTA) technology and X-ray diffraction. The fabrication of MgB₂ bulks and superconducting properties at the temperatures range from 600 to 800°C were reported. And microstructure of MgB₂ bulks were observed by scanning electron microscope (SEM). A method was developed to determine the porosity of MgB₂ and the highest density can be obtained in MgB₂ prepared at 650°C at ambient pressure. It is found that the vapor pressure of Mg increases remarkably at high temperature, leading to the high porosity in MgB₂ samples. MgB₂ bulk with good superconducting property and fine microstructure was synthesized at 750°C.     

Effect of Rare Earths on Corrosion Resisting Properties of Carbon-Manganese Clean Steels

Rareearthelementshavesignificantactionsinsteels ,includingwipingoffimpurityelements ,trans modifyinginclusions ,andimprovingmicrostructureetal,soaddingappropriaterareearthsintosteelscanef fectivelyimprovetheircorrosionresistingproper ties[1,2 ] .Todaypuri…     

A distributed deadlock detection algorithm for mobile computing system

The mode of mobile computing originated from distributed computing and it has the un-idempotent operation property, therefore the deadlock detection algorithm designed for mobile computing systems will face challenges with regard to correctness and high efficiency. This paper attempts a fundamental study of deadlock detection for the AND model of mobile computing systems. First, the existing deadlock detection algorithms for distributed systems are classified into the resource node dependent （ RD ） and the resource node independent （RI） categories, and their corresponding weaknesses are discussed. Afterwards a new RI algorithm based on the AND model of mobile computing system is presented. The novelties of our algorithm are that： 1 ） the blocked nodes inform their predecessors and successors simultaneously; 2） the detection messages （agents） hold the predecessors information of their originator; 3 ） no agent is stored midway. Additionally, the quit-inform scheme is introduced to treat the excessive victim quitting problem raised by the overlapped cycles. By these methods the proposed algorithm can detect a cycle of size n within n - 2 steps and with （ n^2- n - 2 ）/2 agents. The performance of our algorithm is compared with the most competitive RD and RI algorithms for distributed systems on a mobile agent simulation platform. Experiment results point out that our algorithm outperforms the two algorithms under the vast majority of resource configurations and concurrent workloads. The correctness of the proposed algorithm is formally proven by the invariant verification technique.