基于小波的继电保护装置电磁干扰软件防护快速算法研究

基于Mallat分解的小波变换方法能可靠地检测出电力波形中的奇异点,但不适合于实际工程应用。提出了基于S变换的改进的快速算法,即对AD采样点进行前向差分。对于正常的正弦采样信号,点与点之间的采样点值相差较小,所以差分值也较小;而对于奇异信号,在奇异点附近AD采样值有突变,所以差分值较大。因此,选择合适的差分门槛值就可以检测出信号中的奇异点。分析奇异点附近差分值的正负特性可以检测出该奇异点是正常的故障信号或是受干扰信号。最后,通过对典型波形的仿真计算和实际的电磁兼容性试验,验证了该软件抗干扰措施能显著提高数字式继电保护装置运行的稳定性。     

平行单级双倒立摆系统的建模与滑模变结构控制

从两摆间无弹簧连接的平行双倒立摆系统特定物理结构出发,结合控制目标进行合理建模与分析,验证所建模型可行性,讨论系统能控性和参数间的关系,并设计了滑模变结构控制律.该文的理论和方法对平行单级双倒立摆的进一步研究工作具有重要意义.     

基于调峰形势的联络线受电模型及其优化

探讨了基于调峰形势的联络线受电优化模型。该模型根据负荷预测数据,采用分时电价计算方法,综合考虑电网内机组的发电、联络线受电和调峰能力三者的关系,在保证电网安全的条件下,得到了经济效益优化的受电曲线,从而改变了以往受电曲线由人工凭经验制定的状况,为电网的安全经济运行提供了技术依据。     

Nanoscale Calculation of Proton-Induced DNA Damage Using a Chromatin Geometry Model with Geant4-DNA

Monte Carlo simulations can quantify various types of DNA damage to evaluate the biological effects of ionizing radiation at the nanometer scale. This work presents a study simulating the DNA target response after proton irradiation. A chromatin fiber model and new physics constructors with the ELastic Scattering of Electrons and Positrons by neutral Atoms (ELSEPA) model were used to describe the DNA geometry and the physical stage of water radiolysis with the Geant4-DNA toolkit, respectively. Three key parameters (the energy threshold model for strand breaks, the physics model and the maximum distance to distinguish DSB clusters) of scoring DNA damage were studied to investigate the impact on the uncertainties of DNA damage. On the basis of comparison of our results with experimental data and published findings, we were able to accurately predict the yield of various types of DNA damage. Our results indicated that the difference in physics constructor can cause up to 56.4% in the DNA double-strand break (DSB) yields. The DSB yields were quite sensitive to the energy threshold for strand breaks (SB) and the maximum distance to classify the DSB clusters, which were even more than 100 times and four times than the default configurations, respectively.     

加筋土挡墙有限元分析材料模型综述

对20世纪60年代以来国内外加筋土挡墙有限单元分析中采用的几种方法进行了简单介绍,并分别指出它们的优缺点。对加筋土结构有限元计算时经常采用的一些本构模型进行了详细介绍,并着重描述了一种可用于模拟接触面的结构性模型———复合体模型。目前加筋土挡墙的有限元模型基本上均是二维平面模型,建议计算工作者建立三维模型,并考虑筋———土、面板———土、基础———墙体之间相互作用。指出将基于微观理论的结构性模型用于模拟加筋土体,特别是筋———土接触面,是一个新的研究方向。     

OPTIMIZING LAYOUT OF URBAN STREET CANYON USING NUMERICAL SIMULATION COUPLING WITH MATHEMATICAL OPTIMIZATION

1. INTRODUCTION Vehicular emissions have become one of thmain sources of urban atmospheric pollution in Chinwith the development of the urban construction andthe increase in the number of vehicles. There are lots of factors influencing the transport and dispersion of vehicular exhausted pollutants and further influencing the local air quality, among which the gas dynamical effect due to the mechanical turbulence from huge buildings and street canyons is especially remarkable. Previous stu…     

GENERAL CAUCHY PROBLEM FOR THE LINEAR SHALLOW -WATER EQUATIONS ON AN EQUATORIAL BETA-PLANE

1. INTRODUCTION Over the last two decades, studies in the tropical meteorology and ocean have dramatically increased, such as the EI Nino/Southern Oscillation (ENSO), the large-scale heat-induced circulation of the tropical atmosphere and nonlinear effec…     

Multifinality in implicit choice.

This research examines the possibility that people's choices in the service of an explicit focal goal may also reflect their tendency to fulfill implicit background goals and in that sense are multifinal. We carried out 5 experimental studies to investigate this notion. In Experiment 1, a primed implicit goal affected individuals' choices even when those avowedly served an explicit “focal” goal. Experiment 2 replicated this finding with a different type of implicit goals. Experiment 3 found that primed implicit goals had no effect on choices where the options that served them undermined the explicit goal. Experiment 4 found that a primed implicit goal served by a multifinal option does not privilege it over a unifinal option if that goal had been already attained by a different means. Finally, Experiment 5, via 3 types of control groups, showed that choices were affected by both the explicit and implicit goals in isolation, and they shifted toward multifinality when these goals were conjointly present. The discussion considers the integrative potential of the multifinality framework and its implications for a variety of phenomena in the domain of motivated cognition. (PsycINFO Database Record (c) 2011 APA, all rights reserved)