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Influences of Laser Powers on Microstructure and Properties of the Al-Si/Al+Al_2O_3.Coating on the AZ91D Magnesium Alloy

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稀有金属材料与工程 2011年第S4期40卷 226-230页

作者： Qian Jiangang1,Zhang Jiaxiang1,2,Li Shuqing2,Wang Chun2,Gong Shuili21School of Chemistry and Environment,beijing university of Aeronautics and Astronautics,beijing 100191,{3.2Science and Technology on Power Beam Processes Laboratory,Avic beijing Aeronautical Manufacturing Technology Research Institute,beijing 100024,{3. beijing Univ Aeronaut & Astronaut Sch Chem & Environm Beijing 100191 Peoples R China Avic beijing Aeronaut Mfg Technol Res Inst Sci & Technol Power Beam Proc Lab Beijing 100024 Peoples R China

An Al-Si/Al+Al2O3.coating was prepared on an AZ91D Mg alloy substrate by laser cladding of the plasma-sprayed coating.X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to identify the phases and to study the morphology,*** adhesion strength and the porosity ratio of the coating were measured by using a tensile testing machine and an optical microscope (OM),*** microhardness was measured using a micro Vickers hardness *** results show that after laser cladding,the adhesion strength of the coating increased from 10.78 to 25.17 *** the laser power was 1400W,the metastable γ-Al2O3.phase in the coating transformed completely into the stable α-Al2O3.*** with the increase of the laser power,the porosity ratio of the coating *** when the laser power was over 1400W,the porosity ratio *** microhardness of the surface was the hardest which was improved from HV0.05125 to *** larger the power of the laser was,the harder the coating *** when the power was 1600W,the microhardness increased slightly,even the microhardness of the internal decreased.

关键词： laser-clad plasma-sprayed magnesium alloy Al-Si/Al+Al2O3 coating

BEHAVIOR OF FINE V-Ti COMPLEX CARBONITRIDE IN STEEL 09MnVTiN DURING REHEATING

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Acta Metallurgica Sinica(English Letters) 1992年第2期5卷 112-115页

作者： TANG Guoyi ZHENG Yangzeng Yanshan university,Qinhuangdao,china ZHU Jing CAI Qigong Central Iron and Steel Research Institute,Ministry of Metallurgical Industry,beijing,china Yanshan Univ Qinhuangdao China

An investigation was carried out of the morphology and microstructure of V-Ti complex carbonitride in steel 09MnVTiN during reheating under analytical electron *** prior V-rich ellipsoid V-Ti complex carbonitride particles are replaced progressively by Ti-rich cubic ones as the reheating temperature elevated from 1050 to 1400℃.The Ti con- tents in the core and border of particles increase from 15 and 6% in hot-rolled specimens into 84 and94% at 1400℃ respectively.

关键词： steel 09MnVTiN microalloyed steel thermomechanical processing complex carbonitride

非完整力学系统的非Noether守恒量——Hojman守恒量

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物理学报 2004年第3期53卷 666-670页

作者：罗绍凯梅凤翔浙江工程学院数学力学与数学物理研究所北京理工大学理学院北京100081

研究非完整力学系统的非Noether守恒量———Hojman守恒量 .在时间不变的特殊Lie对称变换下 ,给出非完整力学系统的Lie对称性确定方程、约束限制方程和附加限制方程 ,得到相应完整系统的Hojman守恒量以及非完整系统的弱Hojman守恒量和强... 详细信息

研究非完整力学系统的非Noether守恒量———Hojman守恒量 .在时间不变的特殊Lie对称变换下 ,给出非完整力学系统的Lie对称性确定方程、约束限制方程和附加限制方程 ,得到相应完整系统的Hojman守恒量以及非完整系统的弱Hojman守恒量和强Hojman守恒量 .

关键词：分析力学非完整系统 Lie对称性非Noether守恒量 Hojman守恒量对称变换约束限制方程附加限制方程

AGRICULTURAL WEEDING IN CONJUNCTION WITH HERBICIDE APPLICATION IN RICE

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AGRICULTURAL WEEDING IN CONJUNCTION WITH HERBICIDE APPLICATI...

布居分支比模型——一种定性分析上转换效率的有效方法

The 18th Asian-Pacific Weed Science Society Conference

作者： Z.P.Zhang analytical and testing center Chinese Academy of Agricultural Sciences {3. 100081 china.

＜正＞Ten million hectares of rice fields and ten million tons of rice grains were lost by weeds annually in *** weeding was used by farmers,but consumed many *** weed control method for rice seedbed and paddy field can be practiced through agricultural weeding and herbicide *** land preparation,high seeding rates,good water management,transplanting tall old rice seedlings,appropriate time and rate of fertilizer application,rotating rice with a dry land crops and double cropping rice with dry land crops are effective *** weeding is most effective and becomes important,but continuous use of herbicides without integrating other methods induced weed shift,weed resistance to herbicides and environmental *** weeding in conjunction with herbicide application can be the strategy for rice weed control.

关键词： Weed rice integrated weed management

来源： cnki会议评论

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物理学报 2000年第6期49卷 1176-1179页

作者：陈晓波孟超王亚非马辉李美仙北京师范大学分析测试中心北京100875 首都经济贸易大学安全工程系北京100026

通过对在上转换的过程中起关键作用的是发动上转换的关键亚稳态的动力学因素的分析 ,建立了在连续激光激发下的定性分析上转换的“布居分支比 β”物理模型 :即上转换可以由关键亚稳态上的布居再次被激发至更高激发态的分支比 β来描述 ... 详细信息

通过对在上转换的过程中起关键作用的是发动上转换的关键亚稳态的动力学因素的分析 ,建立了在连续激光激发下的定性分析上转换的“布居分支比 β”物理模型 :即上转换可以由关键亚稳态上的布居再次被激发至更高激发态的分支比 β来描述 ;其特别的物理意义在于这种方法易于从总体上对上转换的性能有全面的定性的掌握 .还进一步论证了对于Er3.离子步进吸收上转换 ,石英、五磷酸盐等截止声子能量大于 10 0 0cm-1的材料的上转换发光约为氟化物的万分之一的原因是它们的多声子无辐射弛豫速率Wn 远大于自发辐射速率A ,而自发辐射A和多声子无辐射弛豫Wn 是同时起作用的 .还发现声子对于上转换的有益的价值的条件为Wn

关键词：布居分支比模型上转换陆续激光激发

Simultaneous determination of some trace metal impurities in high-purity sodium tungstate using coprecipitation and inductively coupled plasma atomic emission spectrometry

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Rare Metals 2004年第3期23卷 193-196页

作者： MAXiaoguo KUANGTongchun LIUQianjun centerofAnalysisandtesting GuangdongUniversityofTechnologyGuangzhou510090China

A method based on the combination of coprecipitation with inductively coupledplasma atomic emission spectrometry (ICP-AES) was developed for the determination of impurities inhigh-purity sodium tungstate. Six elements (Co, Cu, Fe, Mn, Ni, and Pb) were coprecipitated bylanthanum hydroxide so as to be concentrated and separated from the tungsten matrix. Effects of somefactors on the recoveries of the analytes and on the residual amount of sodium tungstate wereinvestigated, and the optimum conditions for the coprecipitation were proposed. Matrix-matchingcalibration curve method was used for the analysis. It is shown that the elements mentioned abovecan be quantitatively recovered. The detection limits for Co, Cu, Fe, Mn, Ni, and Pb are 0.07, 0.4,0.2, 0.1, 0.6, and 1.3.μg·g^(-1), respectively. The recoveries vary from 92.5% to 108%, and therelative standard deviations (RSDs) are in the range of 3.1%-5.5%.

关键词： analytical chemistry trace metal determination inductively coupled plasmaatomic emission spectrometry (ICP-AES) coprecipitation sodium tungstate

钢注入Ti^+离子束的真空碳化和微观结构的变化

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分析测试学报 1998年第5期17卷 20-23页

作者：李永良林文廉丁晓纪北京师范大学分析测试中心北京师范大学低能核物理研究所

Ｔｉ＋（１００ｋｅＶ，３×１０１７ｃｍ－２）注入Ｈ１３钢，表面注入层的化学组成和微观结构发生了很大的变化，俄歇分析表明，注入元素Ｔｉ在钢表面层的剖面含量分布呈近似高斯分布，在４０ｎｍ处原子数分数达到其峰值（２５％），... 详细信息

Ｔｉ＋（１００ｋｅＶ，３×１０１７ｃｍ－２）注入Ｈ１３钢，表面注入层的化学组成和微观结构发生了很大的变化，俄歇分析表明，注入元素Ｔｉ在钢表面层的剖面含量分布呈近似高斯分布，在４０ｎｍ处原子数分数达到其峰值（２５％），离子束真空碳化导致在钢的表面形成一层约２０ｎｍ的“渗碳层”。透射电镜分析表明，表面层的微观形貌由注入前的板条状马氏体结构转变成注入后的微胞状结构，电子衍射则进一步证实，表面层已出现非晶化。

关键词：离子注入真空碳化微观结构钢钛离子束

A Practical Reconstruction Algorithm in 2D Industrial CT

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中国体视学与图像分析 2005年第3期 189-193页

作者： LI Hui 1,2, TIAN Jie 2, ZHANG ZhaoTian 3.(1. Department of Education Technology, Capital Normal university, beijing, 10003., china 2. Medical Image Processing Group, Key Laboratory of Complex Systems and Intelligence Science, Institute of Automation, Chinese Academy of Sciences, P.O.Box 2728, beijing, 100080, china 3. Department of Information Science, National Natural Science Foundation of china, beijing, 100085, china)

Computed tomography plays an important role in industrial non-destructive testing, medical applications, astronomy and many other fields to look inside the scanned object and to analysis its inner structures. A non-destructive testing software have been developed to efficiently detect inner flaws of space industrial components. As the core of our software, reconstruction algorithms including preprocess of raw data, re-arrange algorithm and filtered back-projection algorithms have been described in detail in this article. With real raw data from CASC of china, experimental results verified the applied reconstruction algorithm in our software. Furthermore, forward algorithms simulating generation of fan-beam raw data are also presented in this article.

关键词： Reconstruction algorithms industrial CT imaging data preprocess

Calculation of valence band structures of InAs/GaAs quantum ring and quantum dot:using numerical Fourier transform method

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The Journal of china Universities of Posts and Telecommunications 2010年第1期17卷 106-110页

作者： JIA Bo-yong,YU Zhong-yuan,LIU Yu-min,TIAN Hong-da Key Laboratory of Information Photonics and Optical Communications,Ministry of Education,beijing university of Posts and Telecommunications,beijing 100876,{3. [a] Key Laboratory of Information Photonics Optical Communications Ministry of Education Beijing University of Posts Telecommunications Beijing 100876 China

This article puts forward a new method in calculating the band structures of low-dimensional semiconductor structures. In this study, the valence band structures of InAs/GaAs quantum ring and lens-shaped quantum dot are calculated with four-band model, in the framework of effective-mass envelope function theory. To determine the Hamiltonian matrix elements, this article develops the numerical Fourier transform method instead of the widely used analytical integral method. The valence band mixing is considered. The hole energy levels change dramatically with the geometrical parameters of the quantum ring and quantum dot. It is demonstrated that numerical Fourier transform method can be adopted in low-dimensional structures with any shape. The results of Fourier transform method are consistent with the ones of analytical integral in literature; and they are helpful for studying and fabricating optoelectronic devices.

关键词： valence band structures quantum ring quantum dot numerical Fourier transform