Microstructures of high-J c melt-textured YBa2Cu3O7−x /Ag superconductors

Silver has been previously added to the melt-textured YBa₂Cu₃O_7?x in order to increase the critical current density (J _c ) of these materials. However, the effect of this addition on theJ _c is presently unclear. The purpose of this study is to investigate the effect of silver on both critical current density and the microstructure of the melt-textured YBa₂Cu₃O_7?x superconductors by means of X-ray diffraction, optical polarized microscopy, and transmission electron microscopy (TEM). TheJ _c of the MTG YBCO/Ag samples is more than 10⁴A/cm² under the 5 kOe magnetic field. It has been shown that as the concentration of silver increases, the fraction of the 211 phase dispersed within the 123 matrix decreases. Therefore, theJ _c slightly decreases. These results, together with the effect of the 211 phase, dislocations, and other structure defects on flux pinning, are described in this paper.     

高密度封装CAD技术研究

介绍了自行研制的高密度封装外壳设计软件、阐述了其工作原理和功能。应用该软件设计并制作出目前国内最多针脚数的外壳ＰＧＡ２５７。     

聚乙烯工艺及催化剂新进展

综述国内外聚乙烯生产工艺及其催化剂的最新进展，对国内如何开展这方面的工作提出了几点建议。     

Effect of ion energy on hydrogen diffusion in n- and p-GaAs

The ion energy during electron cyclotron resonance (ECR) plasma hydrogenation is found to have a strong effect on both the effective diffusivity and solubility of hydrogen in n⁺ and p⁺ GaAs. For fixed plasma exposure conditions (30 min, 250°C) the diffusion depths for -150 V acceleration voltage are ~50 and ~100% larger, respectively, in p⁺- and n⁺-GaAs compared to 0 V acceleration voltage. The smaller incorporation depths at lower ion energy coincide with much larger peak hydrogen concentrations and higher apparent thermal stability of passivated dopants     

一个有效的圆片规模布局算法

本文提出了一个圆片规模布局算法，它是国外一个相应算法的改进形式，区别在于利用力定向布局法的方式不同。在相对位置阶段，该算法利用布局的层次特性将需确定所有电路元件相对位置的问题缩减至仅需确定宏电路元件相对位置的问题；在实际位置阶段，采用分治策略和取消前阶段层次划分的方式回避了需确定任意元实际位置的问题．其时间复杂度远低于国外相应算法．     

动态全息图快速引入背景条纹技术

音叉振动镜快速引入背景条纹的动态全息图两次曝光法，适用于一次泵浦的双脉冲全息干涉计量术．其背景条纹的密度和方向具有可调性和重复性．     

80钢盘条拉拔断裂原因分析

用扫描电镜、金相显微镜观察分析了80钢盘条拉拔断裂的断口，并对盘条进行了理化检验分析。结果表明，盘条组织中较多的网状二次渗碳体是盘条在拉拔过程中脆断的主要原因。     

关于生物系统超微弱发光的实验研究

生物系统存在超微弱光子辐射现象。通过一系列实验研究,我们认为,这种光子辐射既有低水平化学发光的性质,又有受激辐射的性质,是受激的低水平化学发光。     

直读光度法测定钼铁中的硅

试样经草酸、双氧水分解后，以盐酸羟胺破坏掉多余双氧水。以标准样品作参比，在硫酸－柠檬酸介质中，用钼酸铵显色，抗坏血酸还原，生成稳定的硅钼蓝。此方法可测定１．０％以下的硅，具有快速、准确、灵敏度高等优点。