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Chinese Physics Letters 2012年第4期29卷 229-231页

作者： FAN Xiao-Hong XU Bin NIU Zhen zhai tong-guang TIAN Bin School of Material Science and Engineering Shandong UniversityJi’nan 250101 School of Materials Science and Engineering Shandong Jianzhu UniversityJi’nan 250101 Department of Chemical and Materials Engineering University of KentuckyLexingtonUSA

Diamond is synthesized in an Fe-Ni-C system at high pressure and high temperature,the C sp^(3) content profile through different thicknesses of interface between diamond and the catalyst film is measured by using electron energy loss *** is found that the Csp^(3) content varies from 87.33% to 78.15% when the measured position is located at the inner face near the diamond and then changes to 6 μm further *** electron microscope examinations show that there are different phases in the interface,such as Fe3C,γ-(Fe,Ni),and graphite,but the graphite phase diminishes gradually towards the inner face of the *** results profoundly indicate that the carbon atoms,required for diamond growth,could only come from the carbon-rich phase,Fe3C,but not directly from the *** is possible that carbon atoms from the graphite in the interface first react with Fe atoms to produce carbide Fe3 C during diamond synthesis at high pressure and high *** Fe3 C finally decomposes into carbon atoms with the sp^(3) electron state at the interface to form the diamond.

关键词： spectroscopy carbide Diamond

2524-T34合金疲劳裂纹的萌生和扩展行为

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中国有色金属学报 2010年第1期20卷 37-42页

作者：郑子樵陈圆圆钟利萍佘玲娟翟同广中南大学材料科学与工程学院长沙410083 Department of Chemical and Materials Engineering University of Kentucky

通过四点弯曲疲劳试验研究2524-T34板材的疲劳性能,借助金相和扫描电镜观察疲劳裂纹的萌生和扩展行为。结果表明:2524合金具有良好的疲劳性能,疲劳强度达到屈服强度的80%以上;疲劳裂纹主要在第二相粒子以及第二相粒子/基体界面萌生,裂... 详细信息

通过四点弯曲疲劳试验研究2524-T34板材的疲劳性能,借助金相和扫描电镜观察疲劳裂纹的萌生和扩展行为。结果表明:2524合金具有良好的疲劳性能,疲劳强度达到屈服强度的80%以上;疲劳裂纹主要在第二相粒子以及第二相粒子/基体界面萌生,裂纹扩展过程中的偏转与晶界的阻碍有关;相邻晶粒内两个有利滑移面之间的位向差是控制裂纹通过晶界扩展的重要因素。

关键词： 2524合金疲劳裂纹萌生扩展显微组织

AA2037新型连铸铝合金热轧板退火的正电子湮没研究

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物理学报 2006年第11期55卷 6129-6135页

作者：吴世亮陈叶清吴奕初王少阶温熙宇翟同广武汉大学物理科学与技术学院燕山大学材料工程学院 Chemical and Materials Engineering Department University of KentuckyLexingtonKY 40506-0046USA

应用正电子湮没等技术对AA2037连铸铝合金热轧板不同温度退火下空位-溶质相互作用及沉淀相进行了研究,研究表明:室温时效形成的主要是空位-铜复合体以及空位-镁-铜复合体;温度为200℃退火时由于过渡相的形成正电子平均寿命出现峰值,符... 详细信息

应用正电子湮没等技术对AA2037连铸铝合金热轧板不同温度退火下空位-溶质相互作用及沉淀相进行了研究,研究表明:室温时效形成的主要是空位-铜复合体以及空位-镁-铜复合体;温度为200℃退火时由于过渡相的形成正电子平均寿命出现峰值,符合多普勒展宽谱的商谱中观察到锰信号的存在,表明形成了空位-镁-锰复合体或过渡相中可能存在锰;温度高于250℃时,随着过渡相变粗、溶解,锰信号消失,而铜信号增强,在350℃后铜信号达到饱和,温度为450℃左右时,稳定相形成.

关键词：正电子湮没技术空位-溶质复合体沉淀退火

几种毒性中药的药理作用特点、临床中毒症状及预防措施分析

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新疆中医药 2009年第5期27卷 27-29页

作者：翟铜广库谦阿勒泰地区人民医院新疆阿勒泰836500

中药虽然相对西药毒牲较小,但如对一些毒性中药使用不当,根可能会造成患者出现严重的临床中毒症状。本文对附子、商陆、斑蝥,马钱子四种毒性较大的中药的药理作用特点、临床中毒症状及预防措施进行分析,以期为中医临床治疗的安全用药提... 详细信息

中药虽然相对西药毒牲较小,但如对一些毒性中药使用不当,根可能会造成患者出现严重的临床中毒症状。本文对附子、商陆、斑蝥,马钱子四种毒性较大的中药的药理作用特点、临床中毒症状及预防措施进行分析,以期为中医临床治疗的安全用药提供依据。

关键词：中药毒性药理症状

微孔洞在材料表面的深度变化对应力集中及疲劳裂纹萌生的影响规律研究

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燕山大学学报 2012年第4期36卷 293-297页

作者：许志强臧新良文伟翟同广燕山大学机械工程学院河北秦皇岛066004 肯塔基大学化学与材料工程系美国列克星敦ky40506

采用线弹性有限元法模拟分析了微孔洞相对材料表面深度的变化对应力集中及疲劳裂纹萌生的影响,研究结果表明:微孔洞直径尺寸大小仅影响相应的应力集中分布区域的大小,而微孔洞相对材料表面深度的位置决定了其最大应力集中系数的大小。... 详细信息

采用线弹性有限元法模拟分析了微孔洞相对材料表面深度的变化对应力集中及疲劳裂纹萌生的影响,研究结果表明:微孔洞直径尺寸大小仅影响相应的应力集中分布区域的大小,而微孔洞相对材料表面深度的位置决定了其最大应力集中系数的大小。当微孔洞处于材料表面下并与表面相切时,应力集中系数达到最大值,当微孔洞相对材料表面深度的位置偏离此位置时,应力集中系数急剧下降。研究结果合理解释了实验中观察到的疲劳裂纹在微孔洞处萌生现象,即疲劳裂纹优先在与样品表面相切上半部的微孔洞上萌生,尤其在样品表面下且与表面相切的微孔洞处。

关键词：微孔洞应力集中 FEM 裂纹萌生疲劳

On Some Sums Involving Small Arithmetic Functions

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Acta Mathematica Sinica,English Series 2024年第10期40卷 2497-2518页

作者： Wen guang zhai Department of Mathematics China University of Mining and TechnologyBeijing 100083P.R.China

Let f be any arithmetic function and define S_(f)(x):=Σ_(n≤x)f([x/n]).If the function f is small,namely,f(n)﹤﹤n^(ε),then the error term E_(f)(x)in the asymptotic formula of S_f(x)has the form O(x^(1/2+ε)).In this paper,we shall study the mean square of E_(f)(x)and establish some new results of E_(f)(x)for some special functions.

关键词： Small arithmetic function exponential sum asymptotic formula

The corrosion of AA2037 aluminum alloy in alkaline aqueous solution studied using slow positron beam spectroscopy

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Nuclear Science and Techniques 2016年第2期27卷 6-13页

作者： Jiao-Jiao Wang Zhe-Jie Zhu Wei Yang Yi-Chu Wu tong-guang zhai Hubei Key Laboratory of Nuclear Solid Physics School of Physics and Technology Wuhan University Chemical and Materials Engineering Department University of Kentucky

Corrosion behavior of AA2037 T8 Al alloy in a1 M Na OH aqueous solution was investigated using slow positron beam, together with microscopy techniques and electrochemical tests. The alloy was homogenized at 510℃ for 2 h and 30 s, respectively, before final peak aging, so that one Sample A had more dispersoids than Sample B after homogenization. It was found that S parameter of the Doppler-broadened annihilation was significantly decreased near the surface in both samples in the alkaline solution. With increasing the dissolution time,Sample A showed a slower decrease rate than Sample B,which might imply that the preexistence of more dispersoids might hinder the corrosion process in Sample *** electron microscopy and atomic force microscopy observations found that the surfaces of both samples were uniformly thinned due to intense chemical dissolution by the attack of OH-. With increasing the dissolution time,Sample B was corroded more substantially and produced more and larger pits in a short dissolution time than Sample A. Furthermore, polarization curves showed that Sample A had a lower corrosion current and corrosion rate than Sample B, which revealed that the presence of the dispersoids was responsible for the better corrosion resistance in the alloy.

关键词：慢正电子束碱性水溶液腐蚀行为铝合金扫描电子显微镜光谱溶解时间电化学测试

Rényi's Problem in Short Intervals

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Acta Mathematica Sinica,English Series 2007年第1期23卷 29-36页

作者： Wen guang zhai Department of Mathematics Shandong Normal University Jinan 250014 P R. China

In this paper, we study Rényi＇s problem and other related problems about the additive functions in short intervals. As corollaries, we improve Ivic＇s results.

关键词： additive function Rényi's problem short interval

Tracking the maneuvering spacecraft propelled by swing propulsion of constant magnitude

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Journal of Systems Engineering and Electronics 2020年第2期31卷 370-382页

作者： zhai guang WANG Yanxin ZHAO Qi School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Systems Engineering Research Institute Beijing 100094China

This paper proposes partially norm-preserving filtering for a class of spacecraft in the presence of time-varying, but constant-magnitude maneuver. The augmented state Kalman filter(ASKF) is commonly used to track the maneuvering spacecraft with unknown constant propulsion;however, if the maneuver varies via time, the estimation performance will be degraded. To promote the tracking performance of the ASKF in case of time-invariant,constant-magnitude disturbance, the partially norm-preserving ASKF is developed by applying the norm constraint on the unknown maneuver. The proposed estimator, which is decomposed into two partial estimators and iteratively propagated in turns,projects the unconstrained maneuver estimation onto the Euclidian surface spanned by the norm constraint. The illustrative numerical example is provided to show the efficiency of the proposed method.

关键词： maneuvering spacecraft tracking augmented state norm-preserving Kalman filter

Observer-based control for the platform of a tethered space robot

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Chinese Journal of Aeronautics 2018年第8期31卷 1786-1796页

作者： guang zhai Heming ZHENG Bo ZHANG Aerospace Engineering School Beijing Institute of TechnologyBeijing 100081China Aerospace System Engineering Shanghai Shanghai 201109China

This paper addresses the attitude control problem of a space tethered robot platform in the presence of unknown external disturbance caused by a connecting elastic tether. The tethergenerated unknown disturbance leads to tremendous challenges for attitude control of the *** this work, the perturbed attitude dynamics of the platform are derived with a consideration of the libration of the elastic tether, and then with the purpose of compensating the unknown disturbance, major attention is dedicated to develop a nonlinear disturbance observer based on gyros measurements, after which, an adaptive attitude scheme is proposed by combining the disturbance observer with a sliding mode controller. Finally, benefits from the observer based on an adaptive controller are validated by series of numerical simulations.

关键词： Adaptive control Attitude dynamics Disturbance observerSliding mode controlTethered space robot