多FACTS元件控制变量配对方法与协调投运策略

多个灵活交流输电系统(FACTS)元件接入系统中各FACTS元件控制器间存在负的交互影响。针对已有的变量配对方法和交互影响分析方法存在的局限和不足,根据NI指数理论,提出适用于大规模、多变量的基于NI指数的多控制变量配对方法,运用该方法找到使得控制器间交互影响最小的控制变量最优配对组合。通过对最优配对组合进行分析,得到最优配对组合中与交互影响的严重程度关系最大的一组输入-输出变量。依据这一关系,制定出相应的多FACTS元件协调投入控制策略。以第二代串联型FACTS元件——静止同步串联补偿器(SSSC)为例,通过仿真系统的计算与分析,证明了所提出的多控制变量配对方法的可行性;并利用PSCAD搭建了含多个SSSC元件的系统进行仿真验证,证明了所制定的协调投运策略是可行、实用的。     

Process and compressive properties of porous nickel materials

Abstract

Compressive properties are investigated for the porous Ni materials processing by innovated powder metallurgical (PM) method. The porous Ni materials first show a short elastic region, then a long and oblique stress yield region within the strain range of about 10–50%, and finally, a densification region where the stress increases rapidly.     

Multipass rolling of aluminium alloys: finite element simulations and microstructural evolution

Abstract

Use of numerical predictive methods such as finite element analysis is becoming progressively more common for modelling industrial hot metal working and forming processes. These tools are used not only to predict the thermomechanical behaviour of metals but increasingly to predict microstructural changes by linking them to physical models of recrystallisation and textural evolution. This paper describes the development and application of a fully integrated model for the prediction of thermomechanical and microstructural behaviour during multipass hot rolling of aluminium alloy AA 3104. Finite element code ABAQUS/standard has been used in the work and the process is modelled assuming plane strain conditions. It is shown that for this alloy the static recrystallisation which occurs during interpass cooling does not significantly influence the thermomechanical response during subsequent rolling passes.     

真空校准装置测控系统的设计

介绍了真空比对校准装置的测量原理和工作方法,动态直接比对法、静态直接比对法和静态膨胀法等三种方法,满足了拓宽量程的需求.测控系统是真空比对法校准装置的核心系统,开发了基于虚拟仪器LabVIEW软件的控制程序,并在真空校准装置中的主标准器电容薄膜规和磁悬浮转子规等中得到了应用.详细介绍了系统的硬件组成和软件的设计.实现了数据的自动采集和保存.提高了校准装置的自动化水平和工作效率.该装置可以对1×105～5×10-4Pa范围内的各类真空规进行校准,是一种结构简单、操作方便、检定效率高、实用性强的真空标准装置.     

NI ELVIS在电子技术课程教学中的应用

针对高职人才培养方向,在分析与研究虚拟仪器技术和NI ELVIS平台的基础上,通过设计实例介绍了NI ELVIS在电子技术课程教学中的应用,实践证明,NI ELVIS在电子学教学中的应用具有创新性、灵活性和适应性,有利于开拓学生实践能力和创新能力的培养。     

基于LabVIEW的水平仪自动检测装置

结合步进电机驱动与图像处理技术,设计了一种基于LabVIEW和NI Vision的水平仪自动检测装置。采用高清摄像头读取目标图像信息,利用图像处理的方法实现图像的去噪与目标定位,实现微米级的分辨力,检测系统自动给出检测结果报表。利用LabVIEW的图形化语言,实现了软件设计的快速开发,降低了软件开发的难度。通过对图像采集系统及步进电机驱动电路的大量实验,证明了设计方法可靠实用,提高了检测效率,系统各个模块配合良好,可以准确可靠地得到检测数据,在实际工作中得到了很好的验证。     

Examination of HA230 turbine transition duct

Abstract

The present paper reports the results of an examination of a service run transition duct from one of Siemens' industrial gas turbines and the correlation between the findings for this, and those from the studies undertaken on laboratory exposed Haynes alloy 230 material. The studies have shown that there are changes in the microstructure and hardness of the material that can be related to temperature and time of exposure, and the information gained can lead to estimations of the average component operating temperature. Metallographic studies revealed a high level of heterogeneity of the grains in this transition duct.     

Periodic reverse current electrodeposited nickel pigmented anodised aluminium

Abstract

Aluminium anodically oxidised in sulphuric acid electrolyte was pigmented by an electrolytic colouring process with the use of alternating and periodic reverse current. The applied pigmentation electrolytes were based on nickel. The study reports on resistance against humidity of a selective Ni–Al₂O₃ layer. The samples before and after testing were analysed and compared. The quality of the coating, optical properties and influence of humidity on morphology and composition of the coatings were investigated. The influence of moisture on the quality of the selective Ni–Al₂O₃ layer is comparable to the commercial solar absorber type.     

Nanocrystalline zinc–nickel alloy deposition using pulse electrodeposition (ped) technique

Abstract

Zinc–nickel alloy was electrodeposited on stainless steel using pulse current deposition (PED) from a chloride–sulphate bath. Duty cycles were varied between 10 and 80% and frequency was changed from 10 to 100 Hz. The deposit characteristics were analysed using SEM, XRD and AFM and the results are presented in this paper. The corrosion resistance of zinc–nickel alloy deposited from direct current deposition (DCD) has been compared with that of the deposit obtained by pulse current using the electrochemical impedance spectroscopy method.