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Microstructures and evolution mechanism of highly undercooled Ni-Pb hypermonotectic alloy 总被引:1,自引:0,他引:1
The microstructures and evolution mechanism of the undercooled Ni-20%Pb(molar fraction) alloy were investigated systematically by high undercooling solidification technique. The experiment results indicate that the morphology of α-Ni phase and the distribution of Pb element in undercooled Ni-20% Pb alloys change with the in-crease of undercooling. The main evolution mechanisms of α-Ni are dendrite remelting and recrystallization. Pb phase in the microstructure of Ni-20% Pb hypermonotectic alloy originates from L2 phase separated from the parent melt during the cooling process through immiscible gap and L2 phase formed at the temperature of monotectic trans-formation. The solubility of Ph element in α-Ni phase under high undercooling condition is up to 5.83% which is ob-viously higher than that under equilibrium solidification condition. The real reason that causes the solubility difference is distinct solute trapping. 相似文献
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The automatic crystallization of MgO duringthe sintering of Si_3N_4-MgO-CeO_2 is first discovered.ForSi_3N_4-MgO-CeO_2,ceramics,the MgO-CeO_2 would reactwith SiO_2 to form liquid at 1450℃ and then transform intoglassy phase in the sintered bodies after cooling down.Above1550℃,MgO would crystallize automatically during sinter-ing.So the glassy phase which is harmful to the high temper-ature properties is then eliminated.The present work is ofgreat value for theoretical study and application. 相似文献
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在社会主义市场经济条件下,通过热处理协会中介协调,以及引进、消化、吸收国外先进技术,以实现引进设备国产化,并结合国情加以创新。 相似文献
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钙基复合固硫剂硫化特性的热重研究 总被引:2,自引:0,他引:2
利用热重分析方法研究了钙基固硫剂的硫化反应特性,对影响钙利用率的几个因素进行了探讨。表明添加剂的加入改善了CaO的高温固硫性能,提高了固硫产物的热稳定性,使最佳固硫温度向高温区移动约100℃,热分析条件下钙利用率达65%。 相似文献
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本文通过介绍作者参与的一部分国际竞争项目的招投标文件的编写工作,总结了国内外招标文件技术部分的各自特点及差异,阐述了火力发电厂项目的土建技术标书的编写模式、通用和特殊技术要求部分的编写要点及对编写同类型标书文件的一些借鉴意义。 相似文献
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Java语言国际化的设计与实现 总被引:4,自引:0,他引:4
指出本地化的缺点.深入分析了Java语 言的内部编码,设计并实现了支持国际化的编译器,采用字符编码转换的方案,使多语种字符 、字符串的操作达到了与英文字符、字符串完全一致的目标,并节省了类文件的存储空间,也 使程序具备了有条件的字符集无关性,在一定程度上解决了“万码奔腾”的问题.采用编译信 息和与语境无关的程序代码分离的方案解决了提示信息的国际化问题.提出了采用小字库方 案来解决含有本地字符的程序的真正跨平台问题.通过在加载类时采用对类名进行字符编码 转换的方案解决了JDK(Java development kit)所未能解决的含有本地字符的类名的支持问 题;针对JDK不同版本间的兼容性问题,提出采用根据字符编码特点来选用不同编码转换机制 的解决方案.测试结果证明,采用所设计的国际化方案可实现彻底的国际化支持. 相似文献
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R. Galindo 《Asian journal of control》2012,14(5):1382-1386
Single necessary and sufficient stability conditions, are presented, for a common Linear Time‐Invariant (LTI) controller that simultaneously stabilizes each of a given family of LTI plants. It is assumed that the strictly proper, lumped and LTI plants have stabilizable realizations and are strongly stabilizable, and that the state‐space dimensions of the plants do not change, are even and are double the input‐space dimensions of the plants. The stabilizing controller is designed for a nominal plant and its free parameter is fixed assuring stability for all the plants, and assuring a stable controller. The stability conditions for simultaneous stabilization are based on the parity interlacing property, on a matrix that must be unimodular and on an analytical expression of the stabilizing controllers. Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society 相似文献
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通过共混技术制备高性能的聚合物合金是高分子新型材料开发的重要方向,而改善聚合物间的相容性是其关键所在。本文讨论了聚合物共混的相容性及其增容措施,展望了其发展前景。 相似文献