一种新型的三相小型剩余电流动作保护器

一种新型的三相小型电子式剩余电流动作保护器（RCD）采用三相供电方式给内部的电路板供电。介绍了该RCD主要功能与特性,阐述设计过程中的一些技巧、注意事项以及主要技术参数和测试数据。三相小型电子式RCD在缺相情况下,保持止常工作,具有良好的电磁兼容性,可通过行业内较高标准要求的电磁兼容性试验：该RCD产品具有体积小、材料精简、造价低、整体性能优良,经济实用性良好等优点。     

柴达木盆地西南地区褶皱构造样式

依据构造剖面特征和变形历史,按成因可将柴达木盆地西南区构造分为:冲断褶皱、断展褶皱、滑脱褶皱、底辟(泥拱)和复合型褶皱5种主要构造类型。冲断褶皱构造以基底卷入强烈隆升的单向挤压不对称褶皱构造为主要特征,主要分布于昆北断隆带;断展褶皱构造以基底卷入单向挤压断层扩展不对称褶皱构造为主要特征,主要分布于尕斯—扎哈泉断褶带;滑脱褶皱构造以中浅层滑脱型近于对称褶皱构造为主要特征,主要分布于英雄岭滑脱断褶带和中央坳陷带以及尕斯—扎哈泉断褶带浅部;底辟构造(泥拱构造)以塑性泥岩上拱为主要特征,主要分布于中央坳陷带和英雄岭滑脱断褶带东部;复合褶皱构造由断展和滑脱型共同作用形成,主要分布于尕斯—扎哈泉断褶带、英雄岭滑脱断褶带的西段。      

单芯大截面电缆施工设计剖析

通过一个变电所工程投运后，电缆间产生较大的感应电流，造成不能正常供电运行，论述如何从理论和实践方面分析原因，采取措施，消除不正常现象。同时，也指出单芯大截面电缆施工设计中应注意的事项。     

Studying the viscosity of methane fluid for different resolution levels models using Poiseuille flow in a nano-channel

In this work, the viscosity–temperature–density relationship of methane is investigated for three fully atomistic models (RISM, OPLS and MOPLS) and the corresponding coarse-grained models (CGRISM, CGOPLS and CGMOPLS) by studying the Poiseuille flow inside a silicon nano-channel using molecular dynamic simulation. In order to solve the interaction problem of nano-channel atom and methane molecule, the coarse-grained methane model and the classical Berthelot–Lorentz mixing rules are employed. The optimized coarse-grained methane models are determined using the relative entropy minimization method. The density distribution, stress force profile and velocity profile of coarse-grained models are compared with the fully atomistic models for different nano-channel widths. It is concluded that the results of coarse-grained model are in reasonable agreement with those of the corresponding fully atomistic model. Furthermore, the value of viscosity is calculated by fitting the velocity profile to the continuum solution from the Navier–Stokes equations and then compared to experimental value. The results show that the MOPLS and CGMOPLS models could well predict the viscosity of methane fluid, while the OPLS model performed worst. All simulation results indicate that the coarse-grained models can be used to predict the viscosity of methane fluid accurately.     

The effects of wall roughness on the methane flow in nano-channels using non-equilibrium multiscale molecular dynamics simulation

This paper presents a non-equilibrium multiscale molecular dynamics simulation method to investigate the effects of periodic wall surface roughness on the structure and mass transfer of methane fluid through the silicon nano-channels. In order to accurately capture the trajectories and microstructure of methane nano-fluidics, the present modification of OPLS fully atomic model is employed. Meanwhile, we introduce the corresponding coarse-grained model to solve the problem of wall–fluid interaction for methane Poiseuille flow within silicon atomic walls using the classical Lorentz–Berthelot mixing rules. The geometries of the upper wall roughness are modeled by rectangular waves with different amplitudes and wavelengths. The three-dimensional number densities of C (H) atom and kinetic energy distribution plots give a clear observation of the impacts of surface roughness on the localization micro-information of methane fluid. Moreover, the slip length of fluid over rough surface decreases with the increase in amplitude. The diffusion coefficients appear anisotropic, and the radial distribution functions decrease with the increase in the amplitude. These properties should be taken into account in the design of energy-saving emission reduction nano-fluidic devices. All numerical results also indicate that the presented method not only can well solve the issue of wall–fluid interactions, but also could accurately predict the micro-information and dynamic properties of methane Poiseuille flow.     

SVPWM控制三电平逆变器

论述了空间电压矢量调制（SVPWM）控制二极管钳位式三电平逆变器的原理与实现方法。提出了确定参考矢量的三个规则，并推导出工作矢量作用时间、输出顺序及描述了中点电位的控制规则。通过采用Matlab仿真，结果证明SVPWM控制三电平逆变器的可行性。     

深基坑墙顶水平变形的灰色-时序动态预测

深基坑墙顶水平变形是一个动态的相互依存的过程。在基坑开挖与施工过程中 ,根据变形观测数据用灰色系统理论与时间序列分析方法建立等维新息动态预测预报模型 ,并随着新数据的加入适时修改模型参数。该模型不要求考虑复杂的变形影响因素。工程实例研究表明 :用组合模型预测变形值 ,其误差大多数情况下小于 5 % ;在变形数据变化较大时 ,组合模型预测值明显优于单一模型预测值。在变形变化平稳时 ,用单一的灰色模型或灰色时间序列组合模型预测误差相差不大。预测步数越多 ,则预测精度越低。     

Theoretical Prediction of Strength of Composite with Fractal-tree Structure Fibers

Theoretically;the strength of composite with branched fibers is predicted to be greater than that ofcomposite with plain fibers.The effects of the branching angle of the fiber,and the snubbing frictionbetween the fiber and the matrix at the fiber branching point and the branching step's number of thefiber on the strength of the composite with branched fibers have been studied.It has been shownthat the strength of the composite increases with branching angle,the snubbing friction and thebranching step's number.     

基于人事事件迭代的电网企业人力资源配置预测模犁研究

随着电网规模不断扩大,企业用工总量逐年减少,结构性缺员问题逐渐由量变转为质变,因此实现企业用工的精确预测和科学配置变得尤为重要.结合电网企业用工特点,利用现有人力资源大数据,提出了一种基于人事事件迭代的预测模型,实现对电网企业未来几年人力资源配置情况的系统性精确预测.     

保护东滩湿地爱护绿色家园

湿地是地球上具有高度多样性的独特生态系,它与海洋、森林并列为世界三大生态系。它具有季节或常年积水、生长和栖息喜湿植物、动物和土壤发生熟化3个基本特征。根据1971年2月在伊朗拉姆萨尔签署的《湿地