Nucleation Mechanism for Bainite

Based on the experimental results that solute-depleted zone was observed in Cu-28Zn-4AI (mass fraction) at 523 K, AG is calculated as a positive according to the thermodynamic criteria for the spinodal decomposition of a ternary systems. So, the solute-depleted zone cannot be formed by spinodal decomposition. Dislocation density required by the formation of solute-depleted zone is estimated greater than 7.89×109 cm-2, according to the segregation of solute atoms around dislocations, which is not consistent with the practical situation for the alloy at 523 K. Associated with the internal friction experimental fact that internal friction peaks appear within the incubation for bainitic transformation in Cu-Zn-AI alloy, the equilibrium temperature, TO, is evaluated as 433 K for solute-depleted Cu-25Zn-3.4AI, which is lower than the experimental temperature 523 K. Thus, nucleation by shear mechanism is impossible in this circumstance. Therefore, it is concluded that, like bainite in steels and Ag-Cd, bainite in     

单晶凝固组织的样品尺寸效应

通过对不同直径的单晶样品的凝固实验，研究了样品尺寸对单晶凝固组织的影响规律，研究发现，随样品尺寸减小，单晶凝固组织被细化，尤其一次枝晶间距λ1和枝晶间γ′相尺寸对样品尺寸的依赖性更为明显；样品尺寸影响的要质在于此表面积的变化，进而对凝固过程温度梯度产生影响，最终作用于凝固组织和力学性能，一次枝晶间距λ1和枝晶间γ′尺寸与样品的比表面积近拟呈线性关系，样品尺寸变化，明显改变了单晶生长过程的温度梯度和合金的高温持久寿命。     

桥梁支座的更换

桥梁支座是桥梁上、下部结构的连接点。由于交通运输的需要,交通不能中断或应尽量缩短中断时间,因此,对桥梁支座的更换方案选择显得极其重要。以某工程为例,详细叙述了整体更换桥梁支座的施工方案选择、施工方法及要点。     

DNA序列比对分析中的统计特征方法

提出了一种新的基于统计的序列特征定义,并以此对进化树进行构建.同时对这一方法进行了分类测试和进化树构建测试,发现所得测试结果与同样是用进化树进行构建的基于两序列比对的传统算法比较,其性能和适用性都有明显改善.     

靳善忠副省长在全省煤炭工业工作会议上的讲话(节选)

煤炭作为山西经济发展的支柱产业，在实现全面建设小康社会的奋斗目标过程中，要做出突出贡献，任务非常艰巨，要实现这一奋斗目标，2003年要努力做好6个方面的工作，在新型煤炭工业化道路上迈出更大步伐。     

天津通信企业IT信息网络支撑平台

从系统建设背景、关键技术、创新点及应用情况等方面介绍了天津市通信公司企业IT信息网络支撑平台是一个统一、高效、简洁的综合业务网络平台。     

数据通信网综合网管的设计分析

结合TMN电信管理网的体系结构．对数据通信网综合网管的结构和功能进行了分析。     

Synthesis of LiFePO4 with fine particle by co-precipitation method

LiFePO₄ is a potential candidate for the cathode material of the lithium secondary batteries. A co-precipitation method was adopted to prepare LiFePO₄ because it is simple and cheap. Nitrogen gas was needed to prevent oxidation of Fe²⁺ in the aqueous solution. The co-precipitated precursor shows the high reactivity with the reductive gas, and the single phase of LiFePO₄ is successfully synthesized with the aid of carbon under less reductive conditions. LiFePO₄ fine powder prepared by co-precipitation method shows high rate capability, impressive specific capacity and cycle property.