Recent advances in isotropic conductive adhesives for electronics packaging applications

Isotropic conductive adhesives (ICAs) have recently received a lot of focus and attention from the researchers in electronics industry as a potential substitute to lead-bearing solders. Numerous studies have shown that ICAs possess many advantages over conventional soldering such as environmental friendliness, finer pitch printing, lower temperature processing and more flexible and simpler processing. However, complete replacement of soldering by ICAs is yet not possible owing to several limitations of ICAs which are mainly related to reliability aspects like limited impact resistance, unstable contact resistance, low adhesion and conductivity etc. Continued efforts for last 15 years have resulted in development of ICAs with improved properties. This review article is aimed at providing a better understanding of ICAs, their principles, performance and significant research and development work addressing the technological utility of ICAs.     

快速色谱分析技术在油气勘探中的应用

文章通过对五口井的现场应用介绍，阐述了快速色谱分析技术在油气层识别和解释方面的准确性，探讨了该技术在薄油气层的发现和评价、快速钻进条件下油气层的发现、对油气层全烃组份变化的统一、水平井的地质导向以及排除钻井液添加荆对油气显示的影响五个方面的优势，从而论证了快速色谱分析技术在油气勘探中的应用价值。     

3D velocity from 3D Doppler radial velocity

We present local least squares and regularization frameworks for computing 3D velocity (3D optical flow) from 3D radial velocity measured by a Doppler radar. We demonstrate the performance of our algorithms quantitatively on synthetic radial velocity data and qualitatively on real radial velocity data, obtained from the Doppler radar at Kurnell Radar station, Botany Bay, New South Wales, Australia. Radial velocity can be used to predict the future positions of storms in sequences of Doppler radar datasets.© 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 189–198, 2005     

数字电位器的应用技术

从应用的角度出发，介绍合理设计应用电路和合理选择数字电位器的种类与型号，来克服数字电位器普遍存在的主要缺点的方法。文章具有较强的针对性和可操作性，对数字电位器的应用实践具有指导作用。     

均匀设计法分析制备过程对钴钼硫化物催化剂机械强度的影响

建立了CoMoP/Al2O3加氢精制催化剂机械强度及其可靠性在制备过程中的数学模型,采用均匀设计考察了浸渍、干燥、煅烧、硫化4个制备过程中,浸渍时间、干燥温度、干燥时间、煅烧温度、煅烧时间、硫化温度和硫化升温速率7个实验因子对催化剂强度均值、Weibull模量的影响,同时考察了这些因素对颗粒密度的影响。方差分析表明所有模型都是充足的。实验结果表明,硫化过程是影响催化剂强度均值的主要过程。在实验范围内提高硫化温度、降低硫化时的升温速率有利于提高催化剂的强度。影响催化剂Weibull模量的因素主要为各个制备过程的交互效应。要提高催化剂强度的可靠性就必须全面考虑催化剂制备的各个过程,特别是各个制备过程的交互效应。     

A Study on NMR and GC/MS Spectra of the Isomers of Linear Hexyl Naphthalene

The GC/MS and NMR analysis of the reaction products of naphthalene with 1-bromohexane were reported. The products obtained were suggested to have six isomers of linear hexylnaphthalene and the structure of each isomer was determined by GC/MS and NMR spectra. For the first time, the unique chemical shift data were obtained. The content of each isomer calculated by ¹H NMR and ¹³C NMR spectra was consistent with that by GC/MS spectra, which confirmed the accuracy of NMR data.     

单微乳液中制备Ag/TS-1及丙烯气相环氧化

采用N2H4还原含AgNO3的单微乳液制备了Ag／TS-1催化剂。TEM表征结果表明，Ag高度分散于TS-1之上。以H2、O2存在下的丙烯气相环氧化为探针反应，考察了Ag／TS-1的催化性能。结果表明，采用Ag／TS-1为催化剂，Ag的负载量为1％（质量分数，下同），823 K焙烧后，373 K下反应30 min时，丙烯转化率为1．69％，环氧丙烷（Propylene oxide，PO）选择性为93．2％。当Ag的负载量超过2％时，反应过程中生成大量的热，造成PO的选择性下降。采用Ag的负载量为8％的Ag／TS-1催化剂，消除热效应后，丙烯的转化率为2．46％．PO的选择性为79．2％。     

Results of a User Study on 2D Hurricane Visualization

We present the results from a user study looking at the ability of observers to mentally integrate wind direction and magnitude over a vector field. The data set chosen for the study is an MM5 (PSU/NCAR Mesoscale Model) simulation of Hurricane Lili over the Gulf of Mexico as it approaches the southeastern United States. Nine observers participated in the study. This study investigates the effect of layering on the observer's ability to determine the magnitude and direction of a vector field. We found a tendency for observers to underestimate the magnitude of the vectors and a counter‐clockwise bias when determining the average direction of a vector field. We completed an additional study with two observers to try to uncover the source of the counter‐clockwise bias. These results have direct implications to atmospheric scientists, but may also be able to be applied to other fields that use 2D vector fields.     

Grouped Approach for the Design of H.264/AVC Motion Estimation Architectures

This letter presents a novel approach for organizing computational resources into groups within H.264/AVC motion estimation architectures, leading to reductions of up to 75% in the equivalent gate count with respect to state‐of‐the‐art designs.     

自适应电子镇流器控制器IR2520原理及应用

IR2520是自适应镇流器控制器与600V半桥驱动器单片IC ,可用来驱动半桥配置中的荧光灯。文中介绍了IR2520的主要特点和基本原理 ,给出了它的典型应用电路。