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Preparation and properties of a new cutting pick of coal shearers

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mining Science and technology 2010年第5期20卷 794-796页

作者： LUO Yong ZHANG Dekun WANG Qingliang liu hongtao CHENG Gang ge shirong School of Material Science and engineering China University of Mining & Technology Xuzhou 221116 China School of Mechanical and Electrical engineering China University of Mining & Technology Xuzhou 221116 China

reliability and wear resistance of cutting picks play a significant role in coal mine exploitation with coal *** bit separation,blade breaking,severe erosion of the cutting body and fatigue fractures are the main reasons for failure of cutting *** carried out carburization on a 30CrMnMo alloy to synthesize a new cutting pick material with improved mechanical properties and high wear *** results indicated that carburization can effectively strengthen the surface of the 30CrMnMo alloy by forming a thick carburized layer and thus significantly improve the surface hardness and wear *** addition,the excellent toughness of 30CrMnMo alloy as a substrate of cutting picks can prevent brittle ruptures and fatigue fractures under high impact stress *** significant decrease in both frictional coefficient and rate of erosion of this carburized 30CrMnMo alloy suggests that this alloy is a potential material for cutting picks of coal shearers after rational carburization.

关键词： cutting picks coal shearer carburization wear

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结构系统广义可靠性及数值仿真

铁道学报 2004年第3期26卷 36-40页

作者：李超王金诺西南交通大学机械工程学院

建立了结构系统广义可靠性分析模型。根据随机变量可能同时具有随机性和模糊性的特点,分别提出了模糊强度—随机应力、随机强度—模糊应力和模糊强度—模糊应力情况下的模糊可靠性分析方法。同时,建立了结构系统为独立单元部件串联或并... 详细信息

建立了结构系统广义可靠性分析模型。根据随机变量可能同时具有随机性和模糊性的特点,分别提出了模糊强度—随机应力、随机强度—模糊应力和模糊强度—模糊应力情况下的模糊可靠性分析方法。同时,建立了结构系统为独立单元部件串联或并联组成的模糊可靠性分析模型。考虑到不同模糊随机变量组合下的可靠性积分一般不存在解析解的情况,提出了用仿真法计算可靠度数值解,并阐述了数值仿真的基本原理和步骤。通过实例介绍了方法的具体运用。

关键词：结构系统模糊变量随机变量模糊可靠性数值仿真

Synchronization technology Research based on BOC Modulation

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Synchronization Technology Research based on BOC Modulation

Three Dimension Vision of Laser Image

第三届中国卫星导航学术年会

作者： Zhou Xionglin 1 , liu Bo 2 , Cheng Jian 2 , Dong Feihong 1 1. institute of Communication engineering, PLA university of Science and technology, Nanjing, china, 210007 2. The Key Lab of Military Satellite Communication institute of Communication engineering, PLA university of Science and technology, Nanjing, china, 210007

BOC modulation has the advantages of low interference with BPSK and high anti-fading capability. The main challenge in BOC tracking is represented by the presence of multiple peaks in the correction function. Various tech- niques have been designed for solving the multiple-peak ambiguity problem for special forms of BOC signals. In this paper, Different algorithms, such as BPSKlike, Bump-Jump, Double Estimate and Unambiguity Discrimination are analyzed and compared. A method based on ASPeCT Technique for baseband signal processing is simulated, which can improve code tracking reliability. Simulation results prove the effect of the method.

关键词： satellite navigation BOC modulation multiple peaks ambiguity synchronization

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Three Dimension Vision of Laser Image

2007亚洲显示国际会议

作者： Caicheng Shi~1 Cuifang Zhao~(1 2) Xiaoqiong Li~1 1 Department of Electronic engineering Beijing institute of technology Beijing 100081 china 2 Department of Electronic engineering College of Mathematics Physics and Information engineering Zhejiang Normal university Jinhua 321004 china

＜正＞The Laser Radar（Lidar）system provides much important information for manual target detection and *** offers many advantages over other optical systems,such as intensity,range,azimuth,pitching and *** this pa- per,a novel approach is presented for the development of the 3D Lidar image *** working principle and the main components are *** data of Lidar contains azimuth,pitching,velocity,distance and *** two dimen- sion image of Lidar is mapped by three dimension reference frame *** present the bogus color relies on only intensity or *** according to human vision system theories,the color display was based on *** estab- lished model of Lidar RGB correlates to the range resolution and quantizing bit of *** scheme has great capabili- ty on calculating and *** the software implement of algorithm can be *** results show that the method not only works well for the application with real-time,reliability,and flexible architecture,but also pro- vides a performance in full saturated colors,higher contrast ratio and high resolution.

关键词： Laser Radar(Lidar) Three Dimension Image Vision

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航空电子系统SCI网络可靠性建模研究

系统工程与电子技术 2004年第10期26卷 1526-1528页

作者：姜震邵定蓉熊华钢汪健甄北京航空航天大学电子信息工程学院北京100083 中航第一集团第六一三研究所河南洛阳471009

针对航空电子系统对网络互连技术有严格实时要求的特点,首先建立了可扩展一致性接口(scalableco herentinterface,SCI)网络中的任务模型,然后通过在网络系统可靠性模型引入时间权函数建立了基于实时任务的SCI网络可靠性模型,得出了系统... 详细信息

针对航空电子系统对网络互连技术有严格实时要求的特点,首先建立了可扩展一致性接口(scalableco herentinterface,SCI)网络中的任务模型,然后通过在网络系统可靠性模型引入时间权函数建立了基于实时任务的SCI网络可靠性模型,得出了系统的可靠性矩阵,最后针对联合先进攻击技术(JAST)航空电子结构中SCI蝶型网络给出了建模实例。

关键词：航空电子系统可扩展一致性接口网络可靠性

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基于指数形式渗流定律的软土一维固结分析

土木工程学报 2011年第8期44卷 111-117,131页

作者：李传勋谢康和王坤余坤江苏大学江苏镇江212013 浙江大学岩土工程研究所浙江杭州310058

在土中渗流服从指数形式渗流定律的前提下,对软黏土一维固结理论进行分析研究。首先建立考虑指数形式渗流定律的软黏土一维固结微分方程。然后采用相对稳定的Crank-Nicolson差分格式对控制方程进行时间、空间离散,得到了差分方程及其解... 详细信息

在土中渗流服从指数形式渗流定律的前提下,对软黏土一维固结理论进行分析研究。首先建立考虑指数形式渗流定律的软黏土一维固结微分方程。然后采用相对稳定的Crank-Nicolson差分格式对控制方程进行时间、空间离散,得到了差分方程及其解答,并且将差分计算结果与退化到达西渗流的Terzaghi理论解析解和指数为1.5时的短时间解析解相对比,验证计算程序的可靠性。通过计算分析考虑指数渗流定律情况下的软土地基的一维固结性状,结果表明:考虑指数形式渗流情况下(指数大于1),固结速率在较小的时间因子下要比Terzaghi理论快,而在较大的时间因子下比Terzaghi理论慢,这种现象随着指数值的增大越来越显著;荷载的等效水头与土层厚度的比值对固结性状有显著的影响,比值越小,则固结速率越慢。最后,讨论了达西渗流在实际工程中的适用范围。

关键词：一维固结有限差分法指数形式渗流定律瞬时加荷非达西渗流

A SIMPLIFIED NUMERICAL MODEL OF 3-D GROUNDWATER AND SOLUTE TRANSPORT AT LARge SCALE AREA

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Journal of Hydrodynamics 2010年第3期22卷 319-328页

作者： LIN Lin YANG Jin-Zhong ZHANG Bin ZHU Yan State Key Laboratory of Water Resources and Hydropower engineering Wuhan University Wuhan 430072China institute of Soil Science Chinese Academy of Sciences Nanjing 210008 China

A simplified numerical model of groundwater and solute transport is developed. At large scale area there exists a big spatial scale difference between horizontal and vertical length scales. In the resultant model, the seepage region is particularly divided into several virtual layers along the z direction and vertical 1-D columns covering x-y 2-D area according to stratum properties. The numerical algorithm is replacing the full 3-D water and mass balance analysis as the 2-D Galerkin finite element method in x- and y-directions and 1-D finite differential approach in the z direction. The reasonable method of giving minimum thickness is successfully used to handle transient change of water table, drying cells and problem of rewetting. The solution of the simplified model is preconditioned conjugate gradient and ORTHOMIN method. The validity of the developed 3-D groundwater model is tested with the typical pumping and backwater scenarios. Results of water balance of the computed example reveal the model computation reliability. Based on a representative 3-D pollution case, the solute transport module is tested against computing results using the MT3DMS. The capability and high efficiency to predict non-stationary situations of free groundwater surface and solute plume in regional scale problem is quantitatively investigated. It is shown that the proposed model is computationally effective.

关键词： groundwater movement solute transport simplified model 3-D mass balance numerical simulation

THE NBELC AND NWELC CLASSES OF LIFE DISTRIBUTIONS

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Applied Mathematics(A Journal of Chinese Universities) 1994年第3期9卷 237-243页

作者： Cao Jinhua (1) (2) Wang Yuedong (1) (2) 1. institute of Applied Mathematics Chinese Academy of Science 100080 Beijing 2. Department of Statistics University of Wisconsin 53706 Madison Wisconsin USA

Two new classes of life distributions, namely the class of new better than its equilibrium life in convex ordering (NBELC), and its dual class, the class of flew worse than its equilibrium life in convex ordering (NWELC), are introduced. Their relations to other classes of life distributions, closure properties under the three reliability operations, and inheritance properties under shock models and Laplace-Stieltjes transforms are discussed.

关键词： Life distribution class NBELC NWELC convex ordering shock model LaplaceStieltjes transform.

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家族企业高层管理者胜任特征模型

心理学报 2004年第1期36卷 110-115页

作者：仲理峰时勘中国科学院心理研究所北京大学光华管理学院北京100871 清华大学现代管理研究中心北京100101

通过对 18名家族企业高层管理者的关键行为事件访谈 ,建立了家族企业高层管理者胜任特征模型 ,初步结论是 :(1)采用BEI关键事件访谈方法揭示高层管理者胜任特征模型 ,胜任特征的出现频次和平均等级是较为稳定的指标 ,最高等级分数受到... 详细信息

通过对 18名家族企业高层管理者的关键行为事件访谈 ,建立了家族企业高层管理者胜任特征模型 ,初步结论是 :(1)采用BEI关键事件访谈方法揭示高层管理者胜任特征模型 ,胜任特征的出现频次和平均等级是较为稳定的指标 ,最高等级分数受到了访谈长度的影响。研究还发现 ,胜任特征的平均等级、最高等级都能区分绩效优异和绩效一般的家族企业高层管理者。 (2 )我国家族企业高层管理者的胜任特征模型包括 :威权导向、主动性、捕捉机遇、信息寻求、组织意识、指挥、仁慈关怀、自我控制、自信、自主学习、影响他人等 11项胜任特征。其中 ,与国外企业高层管理者通用胜任特征模型的 9项相一致 ,与国有企业高层管理者的通用胜任特征模型的 5项相一致。而威权导向、仁慈关怀是我国家族企业高层管理者独有的胜任特征。

关键词：胜任特征模型行为事件访谈家族企业高层管理者