1100 kV GIS现场交流耐压试验放电定位技术研究

在1100 kV GIS设备现场交流耐压试验中,放电定位是其中的一项关键问题和技术保证。为确保设备缺陷检查、处理以及故障隐患排除的顺利进行,针对1100 kV GIS交流耐压试验中放电的定位技术展开研究。首先介绍了特高压交流耐压试验流程。随后结合耐压试验放电的特性,对现有放电定位方法的特点及适用性进行了分析。结合放电定位的实际案例,提出了综合多方信息对放电位置进行准确定位的方法。最后对超声检测信号所包含的信息进行了讨论,证实了依据信号强弱和震荡持续时间进行定位具有较高的准确度。研究内容为后续特高压工程建设以及设备厂家提供了一定参考。     

On multigrid-CG for efficient topology optimization

This article presents a computational approach that facilitates the efficient solution of 3-D structural topology optimization problems on a standard PC. Computing time associated with solving the nested analysis problem is reduced significantly in comparison to other existing approaches. The cost reduction is obtained by exploiting specific characteristics of a multigrid preconditioned conjugate gradients (MGCG) solver. In particular, the number of MGCG iterations is reduced by relating it to the geometric parameters of the problem. At the same time, accurate outcome of the optimization process is ensured by linking the required accuracy of the design sensitivities to the progress of optimization. The applicability of the proposed procedure is demonstrated on several 2-D and 3-D examples involving up to hundreds of thousands of degrees of freedom. Implemented in MATLAB, the MGCG-based program solves 3-D topology optimization problems in a matter of minutes. This paves the way for efficient implementations in computational environments that do not enjoy the benefits of high performance computing, such as applications on mobile devices and plug-ins for modeling software.     

河北省南部电网输电线路舞动分析及风险评估

介绍2010年河北省南部电网发生的大范围输电线路舞动情况,分析输电线路舞动的影响因素及河北省南部地区气象、地理特征,结合历史舞动情况和气象地理特征,提出输电线路舞动风险的评估标准,并按严重程度对河北省南部地区划分舞动风险等级,给出不同风险等级输电线路的防舞动建议。     

Narrowband filter radiometer for ground-based measurements of global ultraviolet solar irradiance and total ozone

The ultraviolet narrowband filter radiometer (UV-RAD) designed by the authors to take ground-based measurements of UV solar irradiance, total ozone, and biological dose rate is described, together with the main characteristics of the seven blocked filters mounted on it, all of which have full widths at half maxima that range 0.67 to 0.98 nm. We have analyzed the causes of cosine response and calibration errors carefully to define the corresponding correction terms, paying particular attention to those that are due to the spectral displacements of the filter transmittance peaks from the integer wavelength values. The influence of the ozone profile on the retrieved ozone at large solar zenith angles has also been examined by means of field measurements. The opportunity of carrying out nearly monochromatic irradiance measurements offered by the UV-RAD allowed us to improve the procedure usually followed to reconstruct the solar spectrum at the surface by fitting the computed results, using radiative transfer models with field measurements of irradiance. Two long-term comparison campaigns took place, showing that a mean discrepancy of +0.3% exists between the UV-RAD total ozone values and those given by the Brewer #63 spectroradiometer and that mean differences of +0.3% and -0.9% exist between the erythemal dose rates determined with the UV-RAD and those obtained with the Brewer #63 and the Brewer #104 spectroradiometers, respectively.     

铸造镍铬钼铜耐磨蚀不锈钢的研究

在分析了国内外湿法磷复肥生产过程中的介质特点和设备用材质的基础上，根据金属腐蚀原理，研究设计了适用于这一特殊工况条件下的铸造Ｎｉ－Ｃｒ－Ｍｏ－Ｃｕ合金。经过静态、动态腐蚀试验，动态磨蚀试验，阳极极化曲线测定，以及对机械性能、显微组织的分析和现场装机运行考核证明：这种新材料的使用寿命是理想的。     

逆变式电火花加工脉冲电源的研究

应用现代电力电子技术－－逆变半桥式主回路结构，ＰＷＭ控制技术，研究了新型电火花加工脉冲电源，它将电能利用率提高了２００％，体积和重量减小到十分之一，这种高效节能ＥＤＭ脉冲电源为改善电火花加工整体性能，拓展加工领域提供了技术保护。     

The Emerging Field of Semantic Scientific Knowledge Integration

Interest in and requirements for the next generation of information technology for science are expanding. e-Science has become a growing subject of discussion covering topics such as grid computing for science as well as knowledge-enhanced scientific data retrieval. The demand for deep integration of scientific data and knowledge within and among disciplines is also growing, as larger and broader science questions are becoming more common. Concurrent with the growing demand for next generation information technology for science is a commensurate growth in semantic technologies. We seek to explore the general space of semantic e-Science while focusing on the support and potential for deep data and knowledge integration.     

Efficient topology optimization in MATLAB using 88 lines of code

The paper presents an efficient 88 line MATLAB code for topology optimization. It has been developed using the 99 line code presented by Sigmund (Struct Multidisc Optim 21(2):120–127, 2001) as a starting point. The original code has been extended by a density filter, and a considerable improvement in efficiency has been achieved, mainly by preallocating arrays and vectorizing loops. A speed improvement with a factor of 100 is obtained for a benchmark example with 7,500 elements. Moreover, the length of the code has been reduced to a mere 88 lines. These improvements have been accomplished without sacrificing the readability of the code. The 88 line code can therefore be considered as a valuable successor to the 99 line code, providing a practical instrument that may help to ease the learning curve for those entering the field of topology optimization. The paper also discusses simple extensions of the basic code to include recent PDE-based and black-and-white projection filtering methods. The complete 88 line code is included as an appendix and can be downloaded from the web site .     

Topology optimization considering material and geometric uncertainties using stochastic collocation methods

The aim of this paper is to introduce the stochastic collocation methods in topology optimization for mechanical systems with material and geometric uncertainties. The random variations are modeled by a memory-less transformation of spatially varying Gaussian random fields which ensures their physical admissibility. The stochastic collocation method combined with the proposed material and geometry uncertainty models provides robust designs by utilizing already developed deterministic solvers. The computational cost is discussed in details and solutions to decrease it, like sparse grids and discretization refinement are proposed and demonstrated as well. The method is utilized in the design of compliant mechanisms.