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A bottom-up parser uses an explicit stack to perform a parse – The parsing stack contains tokens, nonterminals as well as some extra state information – The stack is empty at the beginning of a bottom-up parse, and will contain the start symbol at the end of a successful parse
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l In this paper, we focus on the need for l This paper proceeds as follow. l The structure of the paper is as follows. l In this paper, we shall first briefly introduce fuzzy sets and related concepts
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Under appropriate cooling condition, intcrfacial phase appeared between α and β phases in Ti-5Al-2M0-3Zr alloy. Its thickness could reach 100 nm. The interfacial phase was either single layer structure or double layer structure. The monolithic layer adjacent to 3 phase was indentified as fee structure with relationship (110)β// (001)m, [11$\\mathop 1\\limits^{{\\rm{ - - }}} $]β /[110]m. The striated layer adjacent to a phase was indentified as hep with twin relationship {10$\\bar 1$1}<1$\\bar 0$12> to α. Thus, the study provided a new experimental fact for the controversial topic on structure of striated layer. Chemical composition of interfacial phase varied slightly with heat treatments, but always between that of α and β phases
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The relationship among particle size, properties of heat transfer and melting rate of fluxes as well as the main factors which have effect on the prefused fluxes have been studied. Under the conditions of same components and particle size, the melting temperature of prefused fluxes is lower than that of mixed fluxes. With the decreasing of particle size, the difference of melting temperature between the two type of fluxes decreases also. The larger the particle size, the greater the melting rate of prefused type fluxes
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It is shown that the average [O] in the steel can be decreased to 12.86 ppm and there is an optimal [%Si] at the end of melting as 0.11%, at which [O] after vacuum carbon deoxidation (VCD) is minimum. A kinetical model has been deduced to simulate the VCD process. The results show that adding Si before Al is superior to the adding Al before Si with respect to the final [O] in the steel. It is suggested that the melting point of covering slag should be lower than 1550℃, and (FeO+MnO) should be less than 1%, so as to effectively refine GCr15 steel
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Using sand moulds for step-shape casting tests and different silicon percentage of nodular cast iron it was possible to separate structural variations produced during freezing from those occurring at Ac1 transformation temperature. The results show that an increase in silicon content leading to different variation in the matrix structure> leads to a changing mechanical properties of nodular cast irons. Tensile strength and elongation of obtained as-cast nodular cast iron with the composition of 3.9%C, 3.2%Si, 0.5%Mn are maximum of about 524.5N/mm2 and 19.8% accordingly. In the same nodular cast iron, but only with 0.1% Mn the silicon addition first increases after decreases elongation, impact toughness and hardness. But tensile strength changes to the opposite side
文档格式:PPT 文档大小:397KB 文档页数:108
Function of a Parser Takes the sequence of tokens produced by the scanner as its input and produces the syntax tree as its output. Parser Sequence of tokens Syntax-Tree
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应用配有能谱仪的场发射扫描电镜分析了A105钢中裂纹处及基体内残余元素Cu、As和Sn以及P含量.应用Thermo-Calc热力学计算软件计算了A105钢的主要析出相以及钢液中P含量随固相质量分数变化关系.应用Gleeble 1500热模拟试验机对A105钢的高温热塑性进行了研究.发现P偏析是该钢产生横裂的主要原因,残余元素Cu、As和Sn在晶界的偏聚加剧了裂纹的形成,矫直温度偏低加速了裂纹的扩展,而裂纹的形成可能与AlN的析出无关,因为析出的AlN很少
文档格式:DOC 文档大小:58KB 文档页数:8
Franklin D. Roosevelt: The Four Freedoms Mr. Speaker, members of the 77th Congress: I address you, the members of this new Congress, at a moment unprecedented in the history of the union. I use the word “unprecedented” because at no previous time has American security been as seriously threatened f rom without as it is today
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采用真空熔炼法, 经急冷和缓冷两种不同冷却条件制备了Te系化合物TeAsGeSi合金粉体.通过X射线衍射分析, 急冷工艺制备粉体呈非晶态, 缓冷工艺制备的粉体呈晶态, 结晶主相为R-3m空间群的As2GeTe4; 差热-热重分析显示, 升温至350℃时缓冷粉体As2GeTe4成分熔融, 400℃时两种粉体均开始快速失重, 为避免制备过程中发生材料熔融及挥发损失, 确定烧结温度不超过340℃.采用真空热压法制备TeAsGeSi合金靶材, 将两种粉体分别升温至340℃, 加压20 MPa, 保温2 h制备出两种靶材, 其中缓冷粉体制备的靶材致密度高, 为5. 46 g·cm-3, 达混合理论密度的99. 5%, 形貌表征显示此靶材表面平整, 孔洞少, 元素分布均匀
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