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DC ice-melting model for wet-growth icing conductor and its experimental investigation

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Science China(Technological Sciences) 2010年第12期53卷 3248-3257页

作者： FAN SongHai1.2, JIANG XingLiang1. SHU LiChun1. SUN CaiXin1.& WANG DaXing1.2 1.State Key Laboratory of Power Transmission Equipment & System Security and New Technology, Chongqing University, Chongqing 400044, China 2 Sichuan Electric Power Test and Research Institute, Chengdu 61.072, China 1. State Key Laboratory of Power Transmission Equipment & System Security and New Technology Chongqing University Chongqing 400044 China2. Sichuan Electric Power Test and Research Institute Chengdu 610072 China

Icicles are often formed under the downside surface of conductor in the wet growth icing of overhead power line. When the ice deposit around overhead power line is molten by Joule heat produced by current, the pattern of heat transfer of ice deposit with icicles is dissimilar to that without icicle, so the ice-melting model for the columnar icing conductor cannot be applied to icicle-shaped icing conductor. According to the heat-transfer characteristic of the icicle-shaped icing conductor, this paper puts forward a DC ice-melting model for the icicle-shaped icing conductor. Because this full model includes three-dimensional heat-transfer and interface movement, which cannot be solved in closed form, a finite element scheme in space-domain and a finite difference scheme in time-domain are employed to discretize the governing equations. Firstly the whole ice-melting process on the icicle-shaped icing conductor is simulated by this model. Then the simulated results are validated by ice-melting experiments in the artificial chamber. The study from the model and the experiments shows that the size and length of icicle as well as the space between the adjacent icicles are factors to affect ice-melting. With the shorter icicle space, the bigger icicle size and the longer icicle-length, the surface of ice layer is enlarged and then more heat is taken away by the convection and radiation, so the ice melting time will get longer.

关键词： power line icing ice storm ice melting icicle

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基于多参量模型的全局运动估计算法(英文)

系统仿真学报 2008年第19期20卷 5191-5194页

作者：熊正祥康凤举杨常青孙永侃西北工业大学航海学院西安710072 大连舰艇学院大连116018

提出了一种基于特征点匹配的视频序列多参量运动估计算法,即将初始特征点域,进行梯度方向上的极坐标变换,并依据正交特征,作方向轴上的一维投影,构建出新的特征曲线,从而将孤立的特征点匹配转化成特征曲线相关。依据曲线的相关性,完成... 详细信息

提出了一种基于特征点匹配的视频序列多参量运动估计算法,即将初始特征点域,进行梯度方向上的极坐标变换,并依据正交特征,作方向轴上的一维投影,构建出新的特征曲线,从而将孤立的特征点匹配转化成特征曲线相关。依据曲线的相关性,完成特征点对的匹配,最后使用最小二乘解算平移、旋转、缩放等变换参量。实验结果表明:算法的特征点误匹配率1.,平移误差1.像素;各参量估计范围:缩放因子 s:0.71.s1.40,旋转角度 R>30゜,平移参量|d|>35。算法在保证了高精度的同时,具有更为宽松的使用条件及适用性。

关键词：电子稳像多参量全局运动估计特征点匹配曲线相关

Design of artificial neural networks using a genetic algorithm to predict saturates of vacuum gas oil

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Petroleum Science 2010年第1期7卷 118-122页

作者： Dong Xiucheng Wang Shouchun Sun Renjin Zhao Suoqi School of Business Administration China University of Petroleum Beijing 102249 China School of Chemical Science and Engineering China University of Petroleum Beijing 102249 China

Accurate prediction of chemical composition of vacuum gas oil （VGO） is essential for the routine operation of refineries. In this work, a new approach for auto-design of artificial neural networks （ANN） based on a genetic algorithm （GA） is developed for predicting VGO saturates. The number of neurons in the hidden layer, the momentum and the learning rates are determined by using the genetic algorithm. The inputs for the artificial neural networks model are five physical properties, namely, average boiling point, density, molecular weight, viscosity and refractive index. It is verified that the genetic algorithm could find the optimal structural parameters and training parameters of ANN. In addition, an artificial neural networks model based on a genetic algorithm was tested and the results indicated that the VGO saturates can be efficiently predicted. Compared with conventional artificial neural networks models, this approach can improve the prediction accuracy.

关键词： Saturates vacuum gas oil prediction artificial neural networks genetic algorithm

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中国天然气勘探形势及发展趋势

天然气工业 2004年第12期24卷 1-4页

作者：李景明刘圣志李东旭马硕鹏中国科学院广州地球化学所中国石油勘探开发研究院廊坊分院

中国天然气比较丰富 ,目前天然气勘探处于早期阶段 ,天然气的发展空间非常大。文章从中国天然气的勘探开发现状分析入手 ,结合地质研究和技术进步的成果 ,预计中国未来 1.年将发现一批大中型天然气田 ,天然气储量将快速增长 ,到 2 0 1.... 详细信息

中国天然气比较丰富 ,目前天然气勘探处于早期阶段 ,天然气的发展空间非常大。文章从中国天然气的勘探开发现状分析入手 ,结合地质研究和技术进步的成果 ,预计中国未来 1.年将发现一批大中型天然气田 ,天然气储量将快速增长 ,到 2 0 1.年天然气探明可采储量将达到 4× 1. 1. m3 ,天然气产量将达到 1. 0 0× 1. 8m3 。

关键词：中国天然气产量形势天然气储量发展空间预计发展趋势天然气勘探可采储量天然气田

Study of the Influence of the Arrival Rate on Elevator’s Energy Consumption

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Study of the Influence of the Arrival Rate on Elevator’s En...

Review on Sino-German Cooperation Projects on Sustainable Forest Management

第24届中国控制与决策会议

作者： Li Jun-fang 1.2 , Zong Qun 1., Zhang Jing-long 1.1. School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072, China2. School of Electrical Engineering, Tianjin University of Technology, Tianjin 300384, China

In this paper,we have analyzed the arrival rate of the passengers and the energy-cost of the elevator traffic during up-peak. We proposed the dynamic transition point of 4 elevators in order to reduce energy consumption using the nonlinear-map model. The energy-cost depends on the arrival rate and the round-trip time directly, so we give the relationship of the changes of the arrival rate and round-trip time distribution functions. Due to the distribution of the arrival rate depends strongly on the number of passengers arriving at the lobby. The arrival rate of the passengers is divided into three stages. During the lower-peak stages, according to the round-trip time functions, the cars varies from 1.to 4 at the transition point. The simulation shows that the energy consumption of the algrithm proposed in this paper is lower than that of the average arrival rate. This method can also be applied in the other traffic modes.

关键词： Elevator Energy Consumption Round-trip Time Arrival Rate Up Peak

来源： cnki会议评论

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Chinese Forestry Science and Technology 2010年第4期9卷 42-52页

作者： LEI Jingpin1.CHANG Ermei1.JIANG Zeping1.SHEN Suhua2 GUO Yufu2 1. Research Institute of Forestry, Chinese Academy of Forestry, Beijing 1.0091. P.R.China 2. Interantional Cooperation Project Center, State Forestry Administration, Beijing 1.071., P.R.China

Sino-German financial cooperation projects began in the 1.80s, containing both technique and finance areas. Sino-German cooperation projects not only produced the significant eco-efficiency and economic benefits by raising forest coverage, but also made Chinese forestry workers acquire new idea and technology of forestry. However, forestry infrastructure and technological information sevice are still imperfect, forestry policy is not suitable and follow-up funds are insufficient. The outcome and experience of Sino-German cooperation projects after 20 years were summarized through analysis the activities and social ecological benefits. Advanced forest management technology and improvement of forest management were introduced and capacity building was remarkably improved by implementing Sino-German financial cooperation projects. At last, the gaps appearing in the Sino-German cooperation were pointed out, and factors which constrained smooth implementation were analyzed in this paper.

关键词： sustainable forest management Sino-German cooperation project

Coupling analysis of unsteady seepage and stress fields in discrete fractures network of rock mass in dam foundation

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Science China(Technological Sciences) 2011年第S1期54卷 133-139页

作者： CHAI JunRui 1.2 & XU WeiSheng 2 1.College of Hydraulic and Environmental Engineering,China Three Gorges University,Yichang 443002,China 2 College of Hydropower Engineering,Xi’an University of Technology,Xi’an 71.048,China 1. College of Hydraulic and Environmental Engineering China Three Gorges University Yichang 443002 China2. College of Hydropower Engineering Xi’an University of Technology Xi’an 710048 China

The drag force of water flow through single fracture and the coupling characteristics of seepage and stress in single fracture surface are analyzed,and a three dimensional model of coupled unsteady seepage and stress fields is *** model is used to the analysis of foundation rock mass of a high *** the coupling effects are considered,the changes of boundary heads have less influence on the inner head of rock mass,and the strong permeability of main fractures *** the coupling effects are not considered,the fractures distribution affects the inner head more *** the upstream water head declines,the inner head of dam foundation slightly declines and the hydraulic gradient distribution becomes smoother.A bigger upstream water level declining velocity has a stronger lag effect,meanwhile the values of stress components change more *** the upstream water level declining velocity directly affects the stability of rock mass in dam foundation and we should take into account the above factors to make sure the safety of the dam during reservoir level fluctuation period.

关键词： hydraulic engineering unsteady seepage stress coupling fractures network rock mass

A two-dimensional study on natural convection and heat transfer in the enclosure with heat transfer and radiation coupled in natural convection

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Science China(Technological Sciences) 2010年第4期53卷 991-999页

作者： ZHAN NaiYan1.2,YANG Mo1.& XU PeiWei2 1.College of Power Engineering,University of Shanghai for Science and Technology,Shanghiai 200093,China 2 Department of Environmental Engineering,Jilin Architectural and Civil Engineering Institute,Changchun 1.0021.China 1. College of Power Engineering University of Shanghai for Science and Technology Shanghiai 200093 China2. Department of Environmental Engineering Jilin Architectural and Civil Engineering Institute Changchun 130021 China

Numerical investigation using SIMPLE algorithm with QUICK scheme for natural convection and heat transfer in the enclosure bounded by a solid wall and with heat transfer and radiation coupled in natural convection has been *** various parameters are:Rayleigh number(from 1.3 to 1.5),dimensionless conductivity of bounding wall(from 0 to 1.0),dimensionless wall thickness(from 0 to 0.6) and radiation emissivity of all surfaces(from 0 to 1..The results suggest that flow and heat transfer are influenced by *** is a dominant action on flow and heat *** increase of the thermal conductivity of wall,flow and heat transfer turn *** temperature distribution changes *** the thermal conductivity of wall is over a certain critical number,the increasing trend of flow and heat transfer may *** increase of enclosure wall thickness,flow and heat transfer turn *** the enclosure wall thickness is over a certain critical number,the flow and heat transfer will turn slow.

关键词： conduction natural convection radiation couple numerical simulation

Research on DCC Strategy for Grid-Connected Inverter of D-PMSG under Unbalanced Network Voltage Conditions

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Electricity 2012年第Z1期 32-37页

作者： Song Lei1. Zhou Mingxing2, Bai Runqing3 1. Zhejiang Electric Power Corporation Research Institute 2. Ningxia Yinchuan Electric Power Company 3. Gansu Electric Power Research Institute

According to performance analysis of a three-phase grid-connected inverter mathematical model of a directly-driven wind turbine with a permanent magnet synchronous generator (D-PMSG) under unbalanced network voltage conditions, a dual current-loop control strategy (DCC) oriented on positive voltage and negative current is proposed to inhibit the DC voltage fluctuation. Meanwhile, a notch filter is introduced into the conventional control strategy of a phase-locked loop to complete the low voltage ride through (LVRT) ability of the wind generator. A 1.5-MW D-PMSG with a back-to-back IGBT frequency converter was simulated in the PSCAD/EMTDC environment, and simulation results showed that: the maximum wind power tracking was achieved in this system and the proposed DCC strategy could successfully inhibit the rising aging of DC voltage and enhance the ride-through capability of D-PMSG wind generation system under unbalanced network voltage conditions.

关键词： dual current-loop control (DCC) low voltage ride through (LVRT) notch filter maximum wind power tracking