Structures and Dielectric Properties of La-Substituted SrBi8Ti7O27 Ceramics

SrBi₈Ti₇O₂₇ ferroelectric ceramics with mixed Aurivillius structure were modified by La-substitution for Bi, and the dielectric properties were investigated together with the microstructure characterization. Solid solution of Sr(Bi_{1 – x} La _x )₈Ti₇O₂₇ was formed in the present ceramics for x 0.1, and (Bi,La)₄Ti₃O₁₂ secondary phase appeared at x = 0.15. For x 0.25, another phase Sr(Bi,La)₄Ti₄O₁₅ appeared, and (Bi,La)₄Ti₃O₁₂ disappeared gradually with increasing x, and vanished entirely at x = 0.35. With increasing x, both the dielectric constant and dielectric loss of the present ceramics increased firstly and reached their maximums 291 and 0.023 at 1 MHz, then decreased after x > 0.25. The temperature stable high- dielectric ceramics with low dielectric loss were created at the composition x = 0.5: = 122, tan = 0.0003 and = –619 ppm/°C at 1 MHz.     

9．00R20全钢载重子午线轮胎胎体骨架材料研究

为适应9.00R20轮胎实际使用的需要,采用3+9+15×0.22+0.15钢丝帘线作为胎体骨架材料,对胎体强度与胎侧曲挠变形以及胶与钢丝帘线的粘合力进行了分析、研究、改进.产品经过实际使用性能考核,达到改进设计目的,克服了胎侧"拉链式"爆破病疵,提高了轮胎使用安全性.     

A new group-contribution method for critical properties

In the paper, an estimating method for critical properties in group-contribution method is presented.For eliminating the influence of adjacent group and distinguishing isomers, the new method including first-level group-contribution method and second-level group-contribution method is proposed. The new method demonstrates significant improvement in accuracy.     

如何在Delphi中实现错综复杂的复合查询

本文详细介绍了在Delphi中，如何对数据库中的数据错综复杂的复合查询。     

基于点线复合特征的图像十字架检测算法研究

通过对两类样本的详细地分析,本文提出并设计了基于关键点特征的十字架提取检测算法,实验证明了该算法对第一类样本是有效的;在此基础上,分析了该算法对第二类样本的不适用情况,提出了改进算法,即基于点线复合特征的十字架提取检测算法,经试验,该算法运行速度快,成功率高,对两类样本适用性较好。     

在低铬铸铁改性处理中钒渣的冶金物化条件和作用

 在低铬铸铁改性处理中，VS+Ti+Zn复合孕育剂起着良好的孕育处理作用。从热力学角度分析了钒渣作为炼铁工业副产品得到二次利用的可行性，并讨论了冶金综合处理工艺和冶金物化条件对充分发挥钒渣复合孕育效果的作用。结果表明，钒渣复合孕育剂可有效地细化晶粒，改变碳化物形态；钒渣作为一种钢铁冶炼副产品，取代钒铁具有较大的资源利用价值。     

废汽车回收处理技术的研究进展

废汽车中的有价物质包括有色金属、废旧轮胎、玻璃、塑料、黑色金属等,对这些有价物质进行回收利用有利于改善环境状况、节约资源、增加经济效益,本文综述了这些有价物质回收利用技术的研究进展,为我国废汽车的回收处理事业提供了参考。     

二氧化钛-二氧化硅复合材举制备研究及应用

对TiO2-SiO2复合材料的的制备方法进行了综述，同时讨论了在化妆品、涂料、食品抗菌、光催化、亲水薄膜等方面的应用，总结了针对不同的使用目的进行的TiO2包覆SiO2、TiO2包覆SiO2、TiO2与SiO2相互交联反应，并对其机理和应用进行了简单的介绍。     

Effect of Solidification Conditions on Structure and Properties of Rapidly-Solidified Sn-7.5wt%Sb Alloy

The effect of cooling speed on structure and properties of the rapidly-solidified Sn-7.5wt%Sb has been investigated. The samples in this study were prepared using a single roller melt spinning technique with two speeds: 15.7 and 30.7 m/s, respectively. The results showed formation of the intermetallic compound SnSb. This intermetallic compound changes in the amount which precipitated in the two samples. This behavior tends to affect the properties of these two samples. Also higher cooling speed tends to reduce the crystallite size, which in turn reduces the melting point of the resulting alloy compared to that of the lower cooling speed.