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Study on High-power LED Heat Dissipation Based on Printed Circuit Board

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Semiconductor Photonics and Technology 2010年第Z1期 120-124页

作者： WANG Yiwei1,ZHANG Jianxin1,NIU Pingjuan1,LI Jingyi2(1.School of Information and Communication Engineering,tianjin Polytechnic University,tianjin 300160,CHN 2.tianjin Gongda HiYu Solid State Lighting Co,ltd.tianjin 300160,CHN)

In order to study the role of printed circuit board(PCB)in high-power LED heat dissipation,a simple model of high-power LED lamp was *** to this lamp model,some thermal performances such as thermal resistances of four types of PCB and the changes of LED junction temperature were tested under three different working *** obtained results indicate that LED junction temperature can not be lowered significantly with the decreasing thermal resistance of ***,PCB with low thermal resistance can be matched with smaller volume heat sink,so it is hopeful to reduce the size,weight and cost of LED lamp.

关键词： high-power LED printed circuit board(PCB) substrate of heat dissipation thermal resistance junction temperature

Establishing the Harmonious Traffic in Beijing-tianjin-Langfang Cities

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Establishing the Harmonious Traffic in Beijing-Tianjin-Langf...

郯庐断裂带渤中-渤南段新构造运动期断层活动与油气运聚

Extended Research of Cluster Development Among Beijing-tianjin-Hebei and Urban Economic Orientation of Langfang

作者： Yang Wutang~1 Zhang Lingling~2 1 No.4 Pipeline company,Langfang Hebei,065000,china 2 Hebei University of Technology,Beichen tianjin,300401,china

This article mainly discusses the significant meaning of establishing harmonious urban traffic for constructing a harmonious society,the basic connotation of building harmonious urban traffic,and we need to coordinate with the basic relationships with which we will meet and the basic consciousness that we need in the process of building harmonious traffic,etc.

关键词：

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石油与天然气地质 2009年第4期30卷 462-468,482页

作者：姜丽娜邹华耀中国石油大学资源与信息学院北京102249 中国石油天然气股份有限公司大庆油田有限责任公司勘探开发研究院黑龙江大庆163712

郯庐断裂带在新构造运动时期表现非常活跃,在强烈构造背景下,郯庐断裂带渤中-渤南段形成多个大中型油田,断层活动性对油气运聚与保存起到重要作用。利用断层活动速率的方法,从主次断层活动性在不同构造部位的差异方面入手,分析并总结郯... 详细信息

郯庐断裂带在新构造运动时期表现非常活跃,在强烈构造背景下,郯庐断裂带渤中-渤南段形成多个大中型油田,断层活动性对油气运聚与保存起到重要作用。利用断层活动速率的方法,从主次断层活动性在不同构造部位的差异方面入手,分析并总结郯庐断裂带渤中-渤南段新构造运动期断层活动性与油气运聚保存的关系,揭示在强烈活动构造背景下晚期油气成藏机理。研究表明,郯庐断裂带断层活动具有分段性,主干断裂活动性较弱区易于油气汇聚保存,主干断裂活动性较强区油气易散失不利于油气的保存。活跃主干断层与活动性较弱次级断层的有效组合,有利于油气的运聚和保存。

关键词：断层活动速率新构造运动油气成藏郯庐断裂带渤中-渤南地区渤海湾盆地

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有交易成本的证券投资研究

系统工程学报 2003年第3期18卷 198-202页

作者：荣喜民张奎庭王晨亮李践天津大学理学院天津300072 天津城市建设学院天津300381 天津中木实业有限公司天津300201

在分析Markowitz组合证券投资模型的基础上,讨论了交易成本及β系数在组合投资中的重要性,建立了有交易成本,并考虑投资人风险偏好的组合证券投资模型和β系数风险的证券投资模型,给出最优投资策略和投资的有效边界,讨论了交易成本及风... 详细信息

在分析Markowitz组合证券投资模型的基础上,讨论了交易成本及β系数在组合投资中的重要性,建立了有交易成本,并考虑投资人风险偏好的组合证券投资模型和β系数风险的证券投资模型,给出最优投资策略和投资的有效边界,讨论了交易成本及风险偏好对投资策略的影响.最后,通过释例进行了说明.

关键词：证券投资交易成本金融数学风险资产股票价格 β系数证券市场

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支模拉杆拆除及防腐缺陷的防治

水运工程 2007年第S1期 38-40页

作者：刘娜韩志强周润江中交一航局第一工程有限公司天津300456

对混凝土施工中普遍存在的支模钢拉杆拆除及防腐质量缺陷的表现、原因、工程危害等进行分析,提出预防措施。

关键词：模板工程支模拉杆质量缺陷影响因素改进措施

Dynamic Behaviour Modelling and Simulation of the Chain Transmission System for an Armoured Face Conveyor

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Dynamic Behaviour Modelling and Simulation of the Chain Tran...

E-Business·Creative Design·Manufacturing——2009 IEEE 10th International Conference on Computer-Aided Industrial Design & Conceptual Design（CAID&CD’2009）

作者： Baiyan He 1 2 Guoping Li 2 Hui Shi 1 Hang Li 3 1.School of Mechanical Engineering tianjin University tianjin 300072 china 2.R&D Center Zhangjiakou Coal Mining Machinery Co. ltd.Zhangjiakou Hebei Province 075025 china 3.School of Electronic Information&Automation tianjin University of Science&Technology tianjin 300222 china

Armoured face conveyor is a key component of the comprehensive mechanized coal mining equipments which has the characteristics of large size and heavy *** chain transmission system is adopted to transport material from the coal *** dimensional geometry model of the chain transmission system is built by Solidworks software including the chains,sprockets and *** on the geometry model,the contact characteristics of two chains are studied by finite element ***,the multibody model of chain transmission system is investigated in order to get the knowledge of the dynamic and contact behavior under working *** contact stress field is given which is useful for the design of the *** multibody dynamic results such as the chain tension,vibration can be used in the system design and test of the armored face conveyor.

关键词： Armoured Face Conveyor Chain Transmission Dynamics Finite Element Method

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利用热管的新型水平埋管技术

天津大学学报（自然科学与工程技术版） 2004年第11期37卷 1001-1004页

作者：郑宗和杨玉忠葛昕高金水曾宪安天津大学机械工程学院天津300072 中国电子系统工程第四建设有限公司石家庄050061

地源热泵水平埋管占地面积过大一直是难以解决的问题,根据热管高效的传热特性,提出利用热管技术强化地源热泵水平埋管与深层土壤的换热效能,减少水平埋管的占地面积.根据埋管工作的温度范围,设计选择耐腐蚀的不锈钢式热管,并通过理论计... 详细信息

地源热泵水平埋管占地面积过大一直是难以解决的问题,根据热管高效的传热特性,提出利用热管技术强化地源热泵水平埋管与深层土壤的换热效能,减少水平埋管的占地面积.根据埋管工作的温度范围,设计选择耐腐蚀的不锈钢式热管,并通过理论计算,得到热管长度与占地面积的关系.在理论可行性基础之上进行应用可行性分析,方案在保证换热量的条件下能够节省占地47%.

关键词：地源热泵热管水平埋管

2D Micro Angle Sensor Based on Effect of Internal Reflection

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2D Micro Angle Sensor Based on Effect of Internal Reflection

Comprehensive Control on Microstructures and Properties of Medium Carbon V-N Microalloyed Steel Seamless Oil-Well Tubes of Hot-Rolling Non-Quenched/Tempered

第三届国际仪器科学技术学术研讨会

作者： LIU Qing-gang a HU Xiao-peng a LI De-chun b ZHANG Shan c HU Xiao-tang a a State Key Laboratory of Precision Measuring Technology and Instrument tianjin University tianjin 300072 china b 707 Institute of china Shipbuilding Industry Corporation tianjin 300131 china c Shenzhen Coffer Industrial ltd. Guangdong 518128 china

To perform multi-dimension measurement and control as well as monitor the status of moving devices, a new two-dimension (2D) micro angle measurement method was analyzed and the angle sensor was design

关键词： 2D angle measurement internal reflection optical differential

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Journal of Iron and Steel Research International 2011年第S1期18卷 696-700页

作者： LIU Sheng-xin 1,2,LIU Guo-quan 2,CHEN Yong 1,ZHANG Yong-gang 3,HUANG Jian-kai 3 (1.School of Materials Science and Engineering,Zhengzhou University,Zhengzhou 450002,Hennan china 2.School of Materials Science and Engineering,University of Science and Technology Beijing,100083,china 3.Wuxi Seamless Steel Tube company ltd.Wuxi 214026,Jiangsu china) Zhengzhou Univ Sch Mat Sci & Engn Zhengzhou 450002 Hennan Peoples R China Univ Sci & Technol Beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China Wuxi Seamless Steel Tube Co ltd Wuxi 214026 Jiangsu Peoples R China

The relationship between microstructures and mechanical properties of a medium carbon V-N microalloyed steel used for N80 seamless oil-well tubes of hot rolling non-quenched/tempered (non-Q and T) was *** results have shown that volume percentages of upper bainite,modified bainite and ferrite have a decisive influence on impact energies of steel *** the total volume percentage of bainite is larger than 5%,the impact energy of tubes can not satisfy with the industrial ***,if the total volume percentage of bainite is smaller than 5%,then the impact energy of steel tubes enhances with volume percentage of ferrite *** final microstructures have closely relation with tube billet quality,controlled cooling temperature after tube rolling and cooling method after *** quality of medium carbon V-N microalloyed steel for non-Q and T oil-well tubes can be produced through comprehensive control of microstructures and mechanical properties in sub-procedures,especially for tube billet quality and controlled cooling parameters.

关键词： medium carbon V-N microalloyed steel N80 grade seamless oil-well tube microstructure mechanical property