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1.IntroductionItiswellknownthatdiamond,carbide,boride,nitrideandoxidehavehighhardness,lowfrictioncoefficientandgoodwearresistance,yettheiruseislimitedbecauseoftheirlowtensilestrength,weakcapacity0fp0undingandp0ormachinability['].Whileins0lublesolidparticlesareaddedintheelectr0lessbathtoenablethemtoc0dep0sitwithmetals0naplatetoformauniformc0mp0sitelayer,theplatewouldpossessbettercharacteristicsthanthebaremetals0ralloysI2-6].Thestabilizerandactiveagentf0rthebatharedeveloppedbyalot0fexperimentson… 相似文献
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本文对浓硫酸中碳钢电位的振荡行为进行稳定性分析,认为这种电位振荡行为乃是该开放体系远离平衡条件下的一种耗散行为。通过电极表面Fe3+的波动影响到表面膜覆盖度的波动而使电极电位出现振荡。根据所提的模型,较好地解释了文献中的实验现象。 相似文献
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矿岩粉碎颗粒分形结构与粉碎能耗的关系 总被引:1,自引:0,他引:1
用半自动图象分析系统测定了矿岩粉碎后颗粒的周边分形结构,得到粉碎后颗粒表面的分维数在2.033—2.110范围,其分维数随粒度减小而有所增大。按粉碎能耗增量正比?颗粒分形结构的表面积增量原理,得到和Hukki粉碎能耗表达式相同的结果,后者是概括了Rittinger,Kick和Bond三大粉碎能耗学说的共同表达式。 相似文献
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通过对大型CPE装置建筑耐蚀材料选择、防腐蚀构造设计等一系列过程的积极参与和成功实践,揭示了防腐蚀工程设计过程应当遵循的一般规律,为确保大型化工装置正常有效地运转,提供指导与帮助. 相似文献
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Y.G.Wang Z.Q.Li D.Zhang 《金属学报(英文版)》2004,17(1):47-50
The interracial microstructure of ternary-boride-based hard cladding material (YF-2) has been studied using scanning electron microanalyser (SEM),X-ray diffraction (XRD) and energy disperse spectroscopy (EDS). Results show that there are chemical reactions and elements diffusion in the interfacial zone, which make the interface bonding well and bonding strength ideal at the interface.The results gotten by studying of crack produced by Vickers indentation technique in the interfacial zone show that it is difficult to produce crack in the interface, the crack length in the cladding layer is longer than that to the interface,the crack which propagate to the interface stops at the interface rather than propagates along the interface.This suggests negligible residual stresses have developed because of thermal expansion mismatch. The bonding strength of the interface is 550MPa, which has been gotten by cutting test. The result gotten by analyzing the fracture surface shows that the fracture occurs at the side of cladding layer, which confirms that the bonding strength at the interface is higher than that in the cladding layer. 相似文献
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使用分子动力学方法,研究了NaF—CaF_2熔盐体系给出了体系各离子间的偶对分布函数和各种健角几率分布,并在此基础上讨论了体系中的桥和络合模拟结果表明,Ca~(2+)离子周围的F~(-)离子未形成四面体配位,出现象CaF_4~(2-)这样小的络合原子团的可能性不大Ca~(2+)离子周围F~(-)离子排布的一种可能的结构是3个Ca~(2+)离子通过F~(-)离子桥联成一个正三角形,正三角形中心上下各有一个F~(-)离子,每个Ca~(2+)离子在三角形外侧还各有2个F~(-)离子 相似文献
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CHENC Zhaonian JIA Zhengming CHEN Nianyi Shanghai Institute of Metallurgy Academia Sinica Shanghai China associate professor Shanghai Institute of Metallurgy Academia Sinica Shanghai China 《金属学报(英文版)》1993,6(11):324-330
The NaF-CaF_2 system has been studied by molecular dynamics simulation.The paircorrelation functions between cations and anions and the bond angle distributions ofcation and anion triplets have been obtained.The bridging and complexing in the systemare discussed based on the pair correlation functions and bond angle distributions.Theresults simulated show that the F~- ions around a Ca~(2+)ion do not form tetrahedroncoordination,so some of small complexing clusters such as CaF_4~(2-)are hardly found.Apossible structure of F~- ions around Ca~(2+)ions is that three Ca~(2+)ions constitute anequilateral triangle through three Ca-F-Ca bridges and two F~- ions are located overand under the center of the right triangle,respectively.Meanwhile,on the outside of thetriangle,every Ca~(2+)ion has other two F~- ions as its neighbors. 相似文献
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弹性筛面动力学及难筛分物料的透筛机理 总被引:4,自引:0,他引:4
针对难筛分物料的弹性筛面筛分机,建立了筛分机的弹性筛机动力学模型,通过对动力学模型的理论分析,推导出弹性筛面在筛分机振动过程的弹性变形规律,并分析各种粒度的颗粒在弹性筛面上透筛、堵孔的受力情况,给出了透筛力计算公式,指出弹性筛岙透筛力大于刚性筛面透筛力,揭示了弹性筛面克服堵孔主要是筛面弹性变形的作用机理。提出在设计弹性筛面分机时,应将筛分机工作转速设计为筛面一阶固有频率。最后,进行了金属筛面和弹性 相似文献
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通过实例讨论了焊接钢结构选材对产品质量及成本的影响;提出了设计者在考虑所选材料的各项物理机械性能的同时,还应对材料的焊接性予以足够的重视。 相似文献
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W.H. Qi 《金属学报(英文版)》2006,19(3):209-214
The structures of Ag clusters with sizes n=13 to 1157 are studied by tight binding molecular dynamics simulation. It is found that the stable structures of Ag clusters follow the sequence amorphous-crystalline-amorphous-crystalline with the cluster size increasing from 13 to 1157. Furthermore, all the shells of Ag clusters are different from the structure of the corresponding bulk Ag 相似文献
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铁磁材料表面硬度无损测量方法的研究 总被引:3,自引:0,他引:3
通过实验研究了巴克豪森噪声强度与铁磁材料表面硬度之间的关系,结果表明,随材料硬度的降低巴克豪森器材怕的强度逐渐升高,因此可以利用巴克豪森噪声强度对材料的表面硬度进行无损测量。 相似文献
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G. Chu 《金属学报(英文版)》1997,10(1):35-38
1.IntroductionXraydiffractionquantitativephaseanalysisisatechniquewidelyusedinmaterialsscienceandengineeringresarch.ItiswellknownthatXraydiffeactionquantitativephaJseanalysishastheuniqueadvantage0fdetectingn0tonlythepresenceofchemicalcompositionsbutals0theamount0feachphaJse.Al0tofeff0rthasbeenmadetoimprovethemethod.Theinternalstandardmethodandthematrix-flushing0fquantitativeX-raydiffracti0nphaseanalysisrequireallthereferencestandaxdphasesbeaddedtotheanalysedsamples[1'2]-Whenthesampleisamulti… 相似文献
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材料塑性成形过程最优化设计—Ⅰ有限元灵敏度分析方法 总被引:16,自引:2,他引:14
本文采用有限元方法建立了一种非稳态材料塑性成形过程的灵敏度分析理论和模具形状优化设计方法。采用三次B样条函数描述预成形模具形状,B样条函数的控制点坐标(系数)作为优化设计变量,通过对控制点坐标的优化设计,使实际终成形件形状与理想终成形件形状之间的差别最小,从而实现预成形模具形状的优化设计,详细建立了目标函数、有限元节点坐标、节点速度对优化设计变量的解析灵敏度方程及其彼此之间的数学关系,并给出了节点速度灵敏度的边界条件 相似文献