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Experimental measurement of growth patterns on fossil corals:Secular variation in ancient Earth-Sun distances

Chinese Science Bulletin 2010年第35期55卷 4010-4017页

作者： ZHANG WeiJia1,3,4,LI ZhengBin2,3 & LEI Yang1 1 Department of Physics,Peking University,beijing 100871,china 2 Department of electrical Engineering and Computer Science,Peking University,beijing 100871,china 3 State Key Laboratory of Advanced Optical Communication Systems & Networks,Peking University,beijing 100871,china 4 Committee of Yuanpei Honors Program,Peking University,beijing 100871,china Department of Physics Peking University Beijing 100871 China State Key Laboratory of Advanced Optical Communication Systems & Networks Peking University Beijing 100871 China Committee of Yuanpei Honors Program Peking University Beijing 100871 China Department of electrical Engineering and Computer Science Peking University Beijing 100871 China

In recent years,much attention has been given to the increase in the Earth-Sun distance,with the modern rate reported as 5-15 m/cy on the basis of astronomical ***,traditional methods cannot measure the ancient leaving rates,so a myriad of research attempting to provide explanations were met with unmatched *** this paper we consider that the growth patterns on fossils could reflect the ancient Earth-Sun *** mechanical analysis of both the Earth-Sun and Earth-Moon systems,these patterns confirmed an increase in the Earth-Sun *** a large number of well-preserved specimens and new technology available,both the modern and ancient leaving rates could be measured with high precision,and it was found that the Earth has been leaving the Sun over the past 0.53 billion *** Earth's semi-major axis was 146 million kilometers at the beginning of the Phanerozoic Eon,equating to 97.6% of its current *** modern leaving rates are 5-14 m/cy,whereas the ancient rates were much *** results indicate a special expansion with an average expansion coefficient of 0.57H0 and deceleration in the form of Hubble *** the basis of experimental results,the Earth's semi-major axis could be represented by a simple formula that matches fossil measurements.

关键词：地球太阳古代距离生长模式实验石珊瑚量化

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Determination of Young's modulus by nanoindentation

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Science china(Technological Sciences) 2004年第4期47卷 398-408页

作者： MA Dejun1, Chung Wo Ong2, LIU Jianmin1 & HE Jiawen3 1. Surface Engineering research institute, CMES, beijing 100072, china 2. Department of Applied Physics and Materials research Center, The Hong Kong Polytechnic University, Hong Kong, china 3. State Key Laboratory for mechanical Behavior of Materials, Xian Jiaotong University, Xian 710049, china Surface Engineering research institute CMES Department of Applied Physics and Materials research Center The Hong Kong Polytechnic University

A methodology for determining Youngs modulus of materials by non-ideally sharp indentation has been developed. According to the principle of the same area-to-depth ratio, a non-ideally pyramidal indenter like a Berkovich one can be approximated by a non-ideally conical indenter with a spherical cap at the tip. By applying dimensional and finite element analysis to the non-ideally conical indentation, a set of approximate one-to-one relationships between the ratio of nominal hardness/reduced Youngs modulus and the ratio of elastic work/total work, which correspond to different tip bluntness, have been revealed. The nominal hardness is defined as the maximum indentation load divided by the cross-section area of the conical indenter specified at the maximum indentation depth. As a consequence, Youngs modulus can be determined from a nanoindentation test only using the maximum indentation load and depth, and the work done during loading and unloading processes. The new method for determining Youngs modulus is referred to as pure energy method. The validity of the method was examined by performing indentation tests on five materials. The experimental results and the standard reference values are in good agreement, indicating that the proposed pure energy method is a promising substitution for the most widely used analysis models at present.

关键词： Young's modulus, nanoindentation, nominal hardness, indentation work.

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Performance Study of Copper-Bearing High Strength Ship-Hull Steel

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Journal of Iron and Steel research International 2011年第S1期18卷 422-426页

作者： LUO Xiao-bing,YANG Cai-fu,SU Hang,CHAI Feng (Central Iron and Steel research institute,institute for Structural Materials,beijing 100081,china) Cent Iron & Steel Res Inst Inst Struct Mat Beijing 100081 Peoples R China

The variation in microstructures and the mechanical properties of a Copper-bearing high strength ship-hull steel at different aging temperature was *** peak strength was obtained at the aging temperature of 450 ℃,which was attribute to the plentiful Cu precipitates and a bit of Nb(C,N).In the over-aged condition,both the partial recovery of matrix and the coarsening of Cu particles (10-60 nm) caused the loss of the yield strength (YS) and the improvement of *** increase of the ultimate tensile strength (UTS) at aging temperature above 660℃ due to the formation of alloy-rich island structure transformed from the austenite phase upon cooling,and complied with the mixture *** copper-bearing ship steel can exhibit an excellent combination of high strength and toughness while aging at 660 ℃ for 2 hours (UTS-818 MPa,YS-745 MPa,Akv-161 J at-40℃).

关键词： copper-bearing aging HSLA ship-hull steel

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PREPARATION OF BISPHENOL A EPOXY RESIN WATERBORNE DISPERSIONS BY THE PHASE INVERSION EMULSIFICATION TECHNIQUE

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Chinese Journal of Polymer Science 2000年第1期18卷 33-38页

作者： Zhen-zhong Yang De-lu Zhao Polymer Physics Laboratory, institute of Chemistry, Chinese Academy of Sciences, beijing 100080, china 中科院化学所高分子物理及化学国家重点实验室北京

The phase inversion emulsification technique (PIET) is an effective physical method for preparing waterborne dispersions of polymer resins. Some results concerning the preparation of bisphenol A epoxy resin waterborne dispersions by PIET in our laboratory were summarized. electrical properties, rheological behavior and morphological evolution during phase inversion progress were systematically characterized. The effects of the emulsifier concentration and emulsification temperature on phase inversion progress and the structural features of the waterborne particles were studied as well. The deformation and break up of water drops in a shear field were analyzed in terms of micro-theology, while the interaction and coalescence dynamics of water drops were discussed in terms of DLVO theory and Smoluchowski effective collision theory, respectively. Based on the experimental results and theoretical analysis, a physical model of phase inversion progress was suggested, by which the effects of the parameters on phase inversion progress and the structural features of the waterborne particles were interpreted and predicted.

关键词： phase inversion emulsification waterborne dispersions epoxy resin mechanism physical model

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基于闭环形式的车辆减振器热学特性研究

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中国公路学报 2012年第4期25卷 153-158页

作者：么鸣涛龙凯贺李平中国航天科工集团公司第四研究院北京100854 北京理工大学机械与车辆学院北京100081 华北电力大学新能源电力系统国家重点实验室北京102206 中国航天科工集团公司北京无线电测量研究所北京100854

为了解决某车辆被动悬架系统中减振器由于温升过高而漏油失效的问题,提出了车辆悬架系统机械特性与其热学特性相互耦合的模型。采用MATLAB/Simulink建立闭环正反馈系统的热-机耦合模型,并通过仿真计算得到某车辆在多种工况以及不同悬架... 详细信息

为了解决某车辆被动悬架系统中减振器由于温升过高而漏油失效的问题,提出了车辆悬架系统机械特性与其热学特性相互耦合的模型。采用MATLAB/Simulink建立闭环正反馈系统的热-机耦合模型,并通过仿真计算得到某车辆在多种工况以及不同悬架参数条件下减振器的温升特性曲线。研究结果表明:随着路面等级的下降、车速的提高、簧上质量的增大以及悬架刚度的减小,减振器的温度升高;车轮刚度对减振器温升特性影响较小;簧下质量对减振器温升特性无影响。

关键词：汽车工程减振器仿真闭环温升

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ON THE CALCULATION OF STRESS INTENSITY FACTOR K FOR FRAME COMPONENTS

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Journal of Central South University 1995年第2期7卷 37-41页

作者： Liu Yilun Wang Ailun(College of mechanical and electrical Engineering, Central South University of technology, Changsha, 410083, china)He Manjiang(Changsha institute of Mining research) College of mechanical and electrical Engineering Central South University of Technology Changsha China Changsha institute of Mining research China

The stress intensity factor K in the tip of crack which is in the corner of the frame component has been calculated indirectly by means of numeric calculation of J Integral. Some laws and relationships among the stres... 详细信息

关键词： intensity factor J Integral frame component

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The research on the Guidance Model based on Congestion Prediction

The Research on the Guidance Model based on Congestion Predi...

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2010 4th International Conference on Intelligent Information technology Application (IITA2010)

It is very important to provide guidance information timely and correctly in order to decrease traffic jam. This paper proposes the concept of time ahead of guidance first, the queuing theory model was used to forecast short-term travel time, and the guidance model was eastablished, which based on the traffic congestion prediction model. The Sitong Bridge to Zhongguancun First Bridge section was used as a concrete example to check the forecast model and the guidance model.

关键词： traffic jam the queuing theory congestion forecast guidance model

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Investigation on the electrochemical behaviours of Mg_(2-x)Cr_xNi negative electrode

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Rare Metals 2003年第2期22卷 144-149页

作者： XUE Jianshe, WANG Lijun, LUO Yuanhui, LI Guoxun, DU Jun, HU Guangyong, and WANG ChaoqunGeneral research institute for Non-ferrous Metals, beijing 100088, china (Received 2002-09-01) Generald research institute for Non-ferrous Metals 北京 100088

A series of Mg_(2-x)Cr_xNi alloy powder has been produced by combination ofsolid-state diffusion with mechanical grinding (MG). X-ray diffraction patterns show that the alloypowders have an amorphous structure and great increase in the specific surface. Electrochemicaldetection results indicate that the partial substitution of Mg by Cr in Mg_2Ni alloy improves thecycle life of this alloy greatly, which gets up to 100 cycles at 200 mA/g mass discharge current,keeping its mass discharge capacity over 200 mA.h/g. In the meanwhile, partial replacement of Mg byCr also increases the mass discharge capacity compared with Mg_2Ni alloy. With the increasing ofmass discharge current and content of Cr in Mg_(2-x)Cr_xNi, the cycle life of the alloys areincreased and the decay of mass discharge capacity slows down.

关键词： electrochemistry hydrogen storage alloy Ni-MH battery mechanicalgrinding Mg_2Ni

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Identification of the Quaternary low gas-saturation reservoirs in the Sanhu area of the Qaidam Basin,china

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Petroleum Science 2011年第1期8卷 49-54页

作者： Li Xiongyan Li Hongqi Zhou Jinyu He Xu Chen Yihan Yu Hongyan State Key Laboratory of Petroleum Resource and Prospecting China University of PetroleumBeijing 102249China Key Laboratory of Earth Prospecting and Information technology China University of PetroleumBeijing 102249China Department of Computer Science and technology China University of PetroleumBeijing 102249China Exploration and Development institute Changqing Petroleum CompanyShaanxi 710021China

Low gas-saturation reservoirs are gas bearing intervals whose gas saturation is less than 47%. They are common in the Quaternary of the Sanhu area in the Qaidam *** to the complex genesis mechanisms and special geological characteristics,the logging curves of low gas-saturation reservoirs are characterized by ambiguity and diversity,namely without significant log response characteristics. Therefore,it is particularly difficult to identify the low gas-saturation reservoirs in the study *** addition,the traditional methods such as using the relations among lithology,electrical property,physical property and gas bearing property,as well as their threshold values,can not effectively identify low gas-saturation *** solve this problem,we adopt the decision tree,support vector machine and rough set methods to establish a predictive model of low gas-saturation reservoirs,which is capable of classifying a mass of multi-dimensional and fuzzy *** to the transparency of learning processes and the understandability of learning results,the predictive model was also revised by absorbing the actual reservoir *** applications indicate that the predictive model is effective in identifying low gas-saturation reservoirs in the study area.

关键词： Sanhu area Qaidam Basin low gas-saturation reservoir decision tree support vector machine rough set predictive model identification

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LC9铝合金热扭转晶粒细化

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金属热处理学报 1995年第1期16卷 18-24页

作者：白秉哲北京机电研究所

ＬＣ９铝合金在７７３Ｋ热扭转中显微组织由粗大的柱状晶转变为细等轴晶。研究表明：其晶粒细化的过程为：位错的聚集；亚晶网络的形成；亚晶界面两侧晶体位向差的增加；亚晶界转变为晶界。从而细晶网络形成。

关键词：铝合金晶粒细化超塑性形变热处理

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