Distribution of heavy metals during pyrolysis of waste printed circuit boards

The volatilization behavior of Cu, Pb, Sn, Sb, Ni, Zn, Mn, Co, Cr, Cd during pyrolysis of waste printed circuit boards was investigated in a bench-scale fixed-bed pyrolysis system. It was found that volatility of heavy metals increases with operating temperature elevating, and bromine and vacuum have an obvious promoting effect on volatility of most of heavy metals. Over 99% weight of Cu and Ni are still remained in solid residue after pyrolysis, about 20% weight of Sb, Zn and Cd are transfered into liquid and gas during a pyrolysis process at 600 ℃, volatilization fractions of Pb, Sn, Mn, Co, Cr are less than 10% at the same conditions. The contents of heavy metals in liquid and gas products depend on not only volatility of metals, but also their initial contents in printed circuit boards, pyrolysis liquid and gas are primarily contaminated by Cu, Pb, Sn, Sb and Zn, their contents in liquid vary from 10^2 to 10^3 pg/mL, Mn, Co, Cr, Cd were detected only at very low level, less than 10 μg/mL.     

Characteristics of Ions Emitted from Laser-Induced Silver Plasma

In this work, study of laser-induced ions is presented. The plasma was produced by focusing a Nd：YAG laser, with a wavelength of 1064 nm, a pulsed width of 9-14 ns, a power of 1.1 MW and energy of 10 mJ, on silver target in vacuum （10-3 Torr= 1.3332 Pa）. The characteristics of ion streams were investigated by CR-39 detectors located at angles of 0°, 30°, 60° and 90° with respect to normal of the target. The distance between the silver target and each detector was 11 cm. The energy of silver ions was found ranging from 1.5 eV to 1.06E4 eV. There was a high concentration of ions with low energy as compared to those with high energy, showing the energy distribution amongst the ions. The flux of ions was maximum in the axial direction which was decreasing with the angle increase with respect to normal of the target, and finally became minimum in the radial direction. Hence the silver ions have shown anisotropic behaviour.     

中空海胆状结构的碳包覆Fe2O3用作锂离子电池的高性能负极材料

Fe2O3由于成本低廉,储量丰富和理论比容量高(1007 mA hg^-1)等特点,在锂离子电池负极材料的应用中极具发展前景.然而一些问题仍然存在,如:充放电过程中比容量的迅速衰减,不可逆的体积膨胀以及较短的循环寿命等.这些问题严重制约了Fe2O3在锂离子电池中的实际应用.为了突破这些局限,本文以金属-有机骨架(MOF...     

高离化态类铁、类钴、类镍等电子序列离子的能级结构

用多组态自治场方法,系统地计算了高离化态类铁电子序列ＦｅＩ～ＸｅＸＸⅨ离子３ｐ＾６３ｄ＾８、３ｐ＾５３ｄ＾９组态、类钴等电子序列ＣｏＩ～ＸｅＸＸⅧ３ｐ＾６３ｄ＾９,３ｐ＾５３ｄ＾１０,３ｐ＾６３ｄ＾８４ｐ组态、类镍等电子序列ＮｉＩ～ＸｅＸＸⅦ离子３ｐ＾６３ｄ＾９４ｓ,３ｐ＾６ｄ＾９４ｐ,３ｐ＾６３ｄ＾９４ｄ组态的能级。计算结果与实验值符合得较好。     

非间断软件回归测试模型研究

软件测试是开发过程的重要环节。回归错误在开发过程中严重影响着开发的效率,其隐匿特性也使得测试比较困难。因此,本文提出一种非间断测试的模型,用于加强对回归错误的管理,节约不必要的无谓工作时间,提高软件开发的效率。这种模型对用户开发行为进行模拟和推测,在经过大量的数据训练后,寻找测试行为、错误发生等开发动作的捕获点,从而找到最佳的测试策略。在不影响开发人员工作的前提下,可对当前最新的代码进行测试,最大程度上避免回归错误长期隐藏在前期代码中,保持整个开发过程的稳步前进。     

用MasterCAM加工双金属材料链轮硬齿表面

运用MasterCAM软件对双金属材料链轮硬齿表面进行曲面三维造型,编程,并对链轮双金属材料硬齿表面进行曲面合理工艺设计,加工出了符合图纸要求的产品零件。阐述了MasterCAM软件在加工实例产品时编程的基本步骤,重点突出了其加工工艺和加工参数等关键问题。     

现行焦炭强度指标在太钢高炉的适用性探讨

重点论述了焦炭反应性在高炉碱金属循环富集条件下的变化,并根据国内外研究提出的反应性会发生逆转的概念,分析了太钢高炉生产的实际情况,明确了现行焦炭强度指标对太钢高炉生产的指导意义。     

有色金属新材料项目风险管理探析

从安徽鑫科新材料股份有限公司面临的实际问题出发。通过建立系统模型,研究有色金属新材料项目的风险管理问题。     

应用于超薄栅氧化CMOS器件的两种电荷泵改进技术的比较

本文提出了High-low multi-frequency(HLMF)和Average bottom-top-pulse(ABTP)两种电荷泵改进技术,用于提高表征超薄栅氧化CMOS器件界面缺陷的精度.结果表明,在电荷泵技术测量过程中,这两种改进技术能非常有效地扣除漏电流.同时,也分析了电荷泵电流曲线的几个典型特性.由于ABTP技术是用静态模式测量漏电流,所以,在大的负Vbase端,电荷泵电流曲线的尾部出现大的波动.通过比较,我们发现HLMF具有更高的精度,可以作为用于提升表征超薄栅氧化CMOS器件界面缺陷精度的一种重要技术.     

基于免疫的动态垃圾邮件过滤研究

本文基于生物免疫系统防御机制,探讨了将人工免疫原理应用于垃圾邮件过滤系统(IDSFS),通过动态生成垃圾邮件疫苗,提高系统的检出率.另外,针对传统邮件过滤系统存在的错误肯定率、错误否定率等不足及用户对邮件个性化处理的要求,引入用户反馈机制,使得系统精确率、正确率进一步提高.实验结果表明,该系统具有较强的自学习、自适应能力.