双线地段顶进箱涵的一种架空方法

近年来,我们采用在线间设置活支点的方法,较好的解决了区间双线地段的架空难题,成功地顶进了1～12.0m箱形桥及桥高8.7m的箱形桥,下面以陇海线K6811-5.0×4.0箱涵顶进的实例,介绍我们的做法。 （一）线路慢行防护,搭设枕木垛 （二）在线间距中心顺线路方向铺设两路枕木,长度同架空长度。（见图2A处）。 （三）在枕木档间穿Ⅰ30工字钢横梁并每根均与（二）设置的枕木间顶紧。 （四）设置纵梁。两侧各3片Ⅰ55工字钢,两线间为5扣轨束吊梁,将Ⅰ30工字钢联成整体,起分布力的作用。纵梁与横梁用角钢夹板及（?）22螺栓联结牢固。（见图1、图2）。 （五）顶进挖上,箱涵顶进。

DL/T 812-2002《标称电压高于1000V架空线路用绝缘子串工频电弧试验方法》标准的编制说明

文章介绍了DL/T812-2002《标称电压高于1000V架空线路用绝缘子串工频电弧试验方法》标准的主要制定内容,与国内外同类标准水平的对比情况以及重大分歧意见的处理过程。同时对复合绝缘子工频电弧特性进行了详细分析。

既有线下增建立交桥架空方案的比选

针对某一工程实例讨论了工字钢组合梁与D形便梁架空线路方法的比选,得出了工字钢组合梁结构简便,易于安装、拆卸、运输,更有利于保证铁路限界,节约人工、材料的结论。

Numerical Simulation of Wind Turbine Blade-Tower Interaction

Numerical simulations of wind turbine blade-tower interaction by using the open source OpenFOAM tools coupled with arbitrary mesh interface （AMI） method were presented. The governing equations were the unsteady Reynolds-averaged Navier-Stokes （RANS） which were solved by the pimpleDyMFoam solver, and the AMI method was employed to handle mesh movements. The National Renewable Energy Laboratory （NREL） phase VI wind turbine in upwind configuration was selected for numerical tests with different incoming wind speeds （5, 10, 15, and 25 m/s） at a fixed blade pitch and constant rotational speed. Detailed numerical results of vortex structure, time histories of thrust, and pressure distribution on the blade and tower were presented. The findings show that the wind turbine tower has little effect on the whole aerodynamic performance of an upwind wind turbine, while the rotating rotor will induce an obvious cyclic drop in the front pressure of the tower. Also, strong interaction of blade tip vortices with separation from the tower was observed.

Software Tool for the Implementation of the Methodology for Revitalization of High-Voltage Overhead Power Lines

In power systems, a large number of OPLs （overhead power lines） are more than 40 years old and some even exceed 50 years old. The key issue for power systems managers, public utilities companies and electrical engineers today concerns the manner in which available financial resources should be invested in these OPLs to provide the greatest impact on the power system as a whole and to address the OPLs that require urgent revitalization. This paper presents the application of the software tool RevOPL, developed using Microsoft Access utilizing the ＂methodology for revitalization of high-voltage OPLs＂. The aim is to present both the methodology and software to objectively evaluate the condition of an OPL and determine its remaining service life. The application of this software tool provides a proposal for the scheduling and scope of planned revitalization activities, which are obtained through the optimization of the technical characteristics while remaining within the available budget.

Optimum design of lander structure based on finite element method

Three kinds of possible structures of legged lander including monocoqe, semi-monocoqe and space frame are compared, and the lightest space frame structure is selected as the lander's structure. Then, a new lander with four-legged truss structure is proposed. In the premise of ensuring that the main and assistant structures of landing legs are not changed, six possible lander body structures of the new lander are put forward. Taking the section size of each component of lander as design variables, and taking the total mass of the structure as the objective function, the six structures are analyzed by using the software Altair. OptiStruct and the results show that the mass of the basic structure is the lightest, and it is selected as the final design scheme of lander due to its simple structure and convenient manufacture. The optimization on the selected lander structure is conducted, and the detailed results are presented.

Sustainable Livelihood Security in the Poyang Lake Eco-economic Zone:Ecologically Secure,Economically Efficient or Socially Equitable?

Sustainable Livelihood Security(SLS)remains a rarely considered yet important issue for rural sustainability and natural resource management.Particularly in China,rural SLS research in a typical area is urgently needed,but insufficient under the background of National Rural Revitalization and Ten-year Fishing Ban of Yangtze River.Focusing on the policy-targeted inland lake area,we proposed a Livelihood Security Analysis(LSA)framework by establishing an adaptive indicator system and integrating multiple econometrical and geographical methods.This study aims to evaluate the SLS in Poyang Lake Eco-economic Zone comprehensively from the three aspects of ecology,economy and society,analyze their spatial patterns,identify the main constraints,and finally give specific suggestions for improving rural sustainability management.The results showed that rural SLS in the inland great lake area tended to be vulnerable mainly due to the lagging economic efficiency and unbalanced social equality,and mediated by regional ecological characteristics.The overall SLS and Ecological Security Index(ESI)were higher in the north and lower in the south,while Economic Efficiency Index(EEI)and Social Equality Index(SEI)were at the middle level and circularly distributed around Nanchang City.The dominating factors which have greatly shaped the spatial pattern of SLS include rural per capita electricity consumption,fishery breeding area,population dependency ratio,urbanization rate,and fishery population.The obstacle degree is ranked as economic system>social system>ecological system.An outdated economy and incomplete social services are the main constraints,characterized by weak electricity consumption,limited beds in hospitals,low urbanization rate,deficient agricultural machinery power,and a small agricultural output value.Therefore,one urgent need is to activate the rural economy by reinforcing rural electric power facilities and promoting agricultural mechanization.In addition,transforming the peasants/fishermen to the non-agricultural sector should be accelerated,which will help to reduce ecological pressure,boost urban-rural integration and narrow the income gap.