固体理论进展——半世纪回顾

本文回顾了自1964年密度泛函理论(DFT)提出而引入了被称为第一原理计算电子学近半个世纪以来,固体物理在理论、材料与实验上的进展.所选的关注点是那些和微纳电子学与集成电路技术有关的重大进展.内容分为固体理论与计算电子学、低维与超导材料两个部分.硅基CMOS集成电路在经历了本文涵盖的同一历史时期中令人瞠目的高速发展后,无论在研究与产业上都处于一个新发展阶段的十字路口.通过回顾作为现代信息工程基石的固体器件与理论的进展,可以对今后集成电路的发展趋向提供一个分析参考.     

BOD微生物传感器和快速BOD测定仪的研制

报导了一种用皮状丝孢酵母组成的ＢＯＤ微生物传感器和流通式微机化愉速ＢＯＤ测定仪。本法的响应时间为（３～７）ｍｉｎ，测定范围为（１０～６０）ｍｇ／Ｌ，线性方程ΔＩ＝０．４２＋１．６４Ｃ，相关系数γ＝０．０９７。对４０ｍｇ／ＬＢＯＤ标样平行测定８次的相对标准偏差ＲＤ＝３．７１％，加标回收率为９４．１％～１０４．７％     

桂皮酰哌啶类化合物结构与抗惊活性关系的量子化学研究

利用量子化学从头算方法，对13种桂皮酰哌啶类化合物的结构与抗惊生物活性关系进行了研究。采用限制性Hartree-Fock(RHF)方法和6-31G基组，对13种化合物进行全参数优化，得到了它们的稳定构型。并对前线分子轨道能级、轨道组成等性质进行了分析，把它们与实验得到的生物活性参数进行了相关分析，并对某些参量进行了线性回归，得到了回归方程。通过研究发现，桂皮酰哌啶类化合物的抗惊生物活性与分子的前线轨道(HOMO、LUMO)能级和轨道组成存在一定的相关性。通过轨道组成分析发现，具有较高生物活性的分子，其HOMO、LUMO轨道中羰基和烯键所占的比重较大，说明羰基和烯键部位应为此类化合物的活性部位。     

倒装芯片封装结构中SnAgCu焊点热疲劳寿命预测方法研究

由于焊点区非协调变形导致的热疲劳失效是倒装芯片封装（包括无铅封装）结构的主要失效形式.到目前为止,仍无公认的焊点寿命和可靠性的评价方法.文中分别采用双指数和双曲正弦本构模型描述SnAgCu焊点的变形行为,通过有限元方法计算焊点累积蠕变应变和累积蠕变应变能密度,进而据此预测倒装芯片封装焊点的热疲劳寿命.通过实验验证,评价上述预测方法的可行性.结果表明,倒装芯片的寿命可由芯片角焊点的寿命表征;根据累积蠕变应变能密度预测的焊点热疲劳寿命比根据累积蠕变应变预测的焊点热疲劳寿命更接近实测数据;根据累积蠕变应变预测的热疲劳寿命比根据累积蠕变应变能密度预测的热疲劳寿命长;采用双指数本构模型时,预测的焊点热疲劳寿命也较长.     

散射光谱法测定微量银的研究

改造国产荧光分光光度计的激发单色器，利用改造后的荧光计研究了在微酸性介质中，银碘化钾一十六烷基三甲基溴化铵体系的散射光谱，考查了它们的光谱特性，影响因素和适宜反应条件，确定了散射光强度与溶液中银浓度的关系，提出了光散射法测定银的方法。该法在室温下进行，操作方便，具有较高的灵敏度，线形范围是0．0～0．6ug／ml，方法的检出项为0.006ug／ml，用于显影废液中微量银的测定，结果满意。     

Effect of surface passivation on optical and electronic properties of ultrathin silicon nanosheets

The binding energy,electronic structure and optical properties of H-,H 3 C-,and HS-cluster-passivated ultrathin silicon (single-layer and double-layer) nanosheets were calculated using density functional theory based on the plane-wave ultra-soft pseudopotential.Firstly,the most stable configuration was selected from passivated configurations according to the principle of lowest energy after calculating their total energies.Then the density of state and the band structure of the different passivated systems were calculated.It was found that different passivation clusters could affect the forbidden band,theremore the passivated cluster with sulfur could greatly decrease the width of the forbidden band through electron transfer.Lastly,the light absorption and reflection properties were also investigated.All results were conducive to the development of silicon-based optoelectronic devices.     

基于87c196mc单片机控制的蓄电池电机车脉宽调速系统

目前，我国煤矿使用蓄电池机车的调速控制基奉上是采用直流串励电机串电阻调速和可控硅脉冲调速。电阻调速的缺点是机车运行时耗能大，触头易损坏。经济效益差，调速不平稳；可控硅调速工作频率低。缓冲回路复杂，维修精度高。随着电力电子技术的发展。以大功率半导体器件IPM（智能功率模块）为主开关元件、以87c196mc为控制核心的直流斩波调速可以很好的解决以上问题，而且可以简化电路，提高调速的可靠性和调速性能。     

基于PMC结构的同步32路D/A板的设计

针对PMC结构设计了同步32路DA板系统，使用双缓冲技术实时地进行数据的转换，通过TPGA的状态机设计实现完全同步的32路音频输出，达到良好的相位一致性和幅度一致性，极好的满足设计指标。可灵活地配置FPGA来适用不同的需求。     

Facing the classification of binary problems with a hybrid system based on quantum-inspired binary gravitational search algorithm and K-NN method

Since given classification data often contains redundant, useless or misleading features, feature selection is an important pre-processing step for solving classification problems. This problem is often solved by applying evolutionary algorithms to decrease the dimensional number of features involved. Removing irrelevant features in the feature space and identifying relevant features correctly is the primary objective, which can increase classification accuracy. In this paper, a novel QBGSA–K-NN hybrid system which hybridizes the quantum-inspired binary gravitational search algorithm (QBGSA) with the K-nearest neighbor (K-NN) method with leave-one-out cross-validation (LOOCV) is proposed. The main aim of this system is to improve classification accuracy with an appropriate feature subset in binary problems. We evaluate the proposed hybrid system on several UCI machine learning benchmark examples. The experimental results show that the proposed method is able to select the discriminating input features correctly and achieve high classification accuracy which is comparable to or better than well-known similar classifier systems.     

电子封装焊点可靠性及寿命预测方法

高功率、高密度、小型化是现代电子封装结构的基本特征，软焊料是电子封装中应用最广的连接材料，一个焊点的破坏往往导致整个封装结构的失效。软钎料的无铅化是目前发展的重要趋势。针对目前所开发的无铅焊料，文中介绍电子封装结构中焊点的破坏行为和焊点寿命预测的基本方法。