Phase field simulation of interatomic potentials for double phase competition during early stage precipitation

Phase field model was employed to study the variations of interatomic potentials of Ni 3 Al (L1 2 phase) and Ni 3 V (DO 22 phase) as a function of temperature and concentration. The long-range order (LRO) parameter related interatomic potentials equations formulated by Khachaturyan were utilized to establish the inversion equations for L1 2 and DO 22 phases, with which interatomic potentials could be calculated. The interatomic potentials of Ni-Al and Ni-V exhibited approximately linear increases and decreases, individually, with enhanced Al concentration. Substituting the inverted interatomic potentials into the microscopic phase field equations led to three cases of precipitation sequence: the DO 22 phase preceded L1 2 phase precipitating at the interatomic potentials of Ni-V > Ni-Al; the vice cases; and two phases precipitated simultaneously at interatomic potentials of Ni-V and Ni-Al were equal.     

Angular dependent NEXAFS study of the molecular orientation of PTCDA multilayers on Au （111） surface

The molecular orientation of perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) multilayers adsorbed on Au (111) surface has been investigated using angular dependent O K-edge near edge X-ray absorption fine structure (NEXAFS) spectroscopy. The significant angular dependence of important resonant structures (π* and σ*) reveals that PTCDA molecules adopt an ordered geometry on the substrate surface. The average tilt angle of the PTCDA molecular planes is 27°±10° from the Au (111) surface.     

Evolution of the East Asian monsoon and its response to uplift of the Tibetan Plateau since 1.8 Ma recorded by major elements in sediments of the South China Sea

Evolution of the East Asian monsoon and its response to uplift of the Tibetan Plateau has been investigated in the study of global change. Core sediment samples drilled in the South China Sea during ODP Leg184 are the best materials for studying long-term variability of the East Asian monsoon. R-mode factor analysis of major elements in the fine grain-sized carbonate-free sediments (<4 μm) of the upper 185 mcd splice of ODP Site 1146 drilled during Leg184 in the South China Sea shows that Ti, TFe2O3, MgO, K2O, P, CaO, and Al2O3 are representative of a terrestrial factor. The variation in the terrestrial factor score is subject to chemical erosion in the source region and thus indicates the evolution of the East Asian summer monsoon. The terrestrial factor score has three stepwise decreases at ~1.3 Ma, ~0.9 Ma, and ~0.6 Ma, indicating the phased weakening of the East Asian summer monsoon is related to wholly stepwise, quick uplifts of the Tibetan Plateau since 1.8 Ma. The periodic fluctuation of the terrestrial factor score since ~0.6 Ma indicates that the glacial-interglacial cycles have been the main force driving the evolution of the East Asian monsoon. As in the case of Chinese loess, the long-term evolution of the East Asian monsoon recorded in sediments of the South China Sea reflects a coupled effect of the glacial-interglacial cycle and uplift of the Tibetan Plateau.     

交换环上辛代数和正交代数的抛物子代数的导子

设R是有1的交换环,L是R上的辛代数或正交代数,h是L的极大环面子代数,b是L中包含h的标准Borel子代数.在2∈R可逆的条件下,本文详细描述了b与L之间的中间李代数,并且证明这些中间李代数的导子都是内导子.     

环境温度对斜拉桥动力特性的影响分析

基于东海大桥主航道斜拉桥健康监测系统测得的一年的环境温度和结构响应的数据分析了环境温度对结构动力特性的影响。首先基于环境温度的监测数据对环境温度的分布特点进行了分析,环境温度沿桥梁纵向具有很强的一致性,沿箱梁截面具有明显的温度梯度。接着分析环境温度对结构动力特性的影响机理,并通过实际监测数据进行了验证,其结果表明理论分析与实际监测数据具有很好的一致性。最后基于ARX模型对于环境温度对结构动力特性影响的惯性效应进行了分析,表明环境温度的影响具有明显的时间滞后效应,同时基于多点温度能够等效表示环境温度的惯性效应。     

基于本体几何特征分析的产品制造行为推理

将本体理论应用于产品制造行为建模和推理中.通过分析零件的加工面邻接图,逐个提取产品的几何特征,从而形成制造行为的静态本体模型;以无向图的布尔运算和本体建模理论作为基础,分析零件的加工进刀方向,对静态本体模型中的特征归纳优化,形成可供分析的几何本体的过程序列模型.     

人骨形态发生蛋白4多拷贝表达盒的构建及其表达

为了了解在毕赤酵母中人骨形态发生蛋白4基因剂量对其表达量的影响,利用毕赤酵母表达载体pAO815质粒上的2个同尾酶BglⅡ和BamH Ⅰ在体外构建了人骨形态发生蛋白4成熟肤序列1,3,6,9个拷贝表达盒,并对它们进行表达量研究.结果表明,在毕赤酵母中表达人骨形态发生蛋白4蛋白时,1个拷贝基因能达到最大表达量,增加人骨形...     

轨道交通多线换乘设计

文章以上海桌综合交通枢纽地铁站为研究对象,对城市轨道交通的换乘原则、换乘方式及近远期结合建设顺序注意事项进行了阐述.     

黑龙江七星河国家级湿地自然保护区生态旅游开发的SWOT分析

采用SWOT分析法较为详细地分析了七星河国家级湿地自然保护区发展生态旅游业的优势、弱势、机遇和威胁。得出黑龙江七星国家级河湿地自然保护区不仅具备景观资源独特、动植物资源丰富、旅游环境优越等开展湿地生态旅游的先决条件,而且拥有国内外生态旅游发展的有利形势和地方政策大力支持的大好机遇;但同时存在湿地保护和专业人员匮乏、旅游...     

防倾翻装置在集装箱正面吊运机上的应用

设计了一种堆码、装运港口集装箱的机械,具体为一种集装箱正面吊运机防倾翻装置.其特点是通过特殊加工的转轴在带有长形内孔的钢套中上下运动,并用接近开关检测这种运动的距离,当超出安全距离时,控制器发出断电保护指令,停止危险方向动作输出.这种结构方式控制精确、稳定可靠,而且利用后桥的铰接摆动功能,使整车在不平路面也能平稳行驶....