微波单片有源滤波器负阻电路的实现方法

论述了用于微波单片有源滤波器负阻电路的实现方法，给出了三种由单管ＦＥＴ构成的负阻电路，以及用ＭＭＩＣ工艺能够实现的矩形螺旋电感与ＦＥＴ实现的负阻电路，并对电路进行了详细的分析与计算机模拟，分析与模拟结果显示用单管ＦＥＴ实现的负阻电路结构简单，在谐振频率点，最大负阻值可达几千欧姆，而且，综合出的负阻电路完全可以用现有的ＭＭＩＣ工艺实现，为进一步设计微波有源滤波器打下了良好的基础。     

Superconducting joints for silver-clad BSCCO tapes

The advent of high-T_c superconducting tapes for a variety of applications has resulted in the need for superconducting joints. Although long-length tapes can be custom-made for some applications, interconnections between subcoils of a magnet or shorter-length conductors for coil winding and current leads, make the development of such joints imperative. Additionally, high-quality short-or medium-length conductors, which are easier to make, can be joined for improved performance. Employing a novel chemical etching technique, we have fabricated lap joints between short lengths of silver-clad BSCCO tapes. Each joint was formed by etching the silver away and bringing together the exposed superconductor cores of two tapes together. The joined tapes were then subjected to a series of thermomechanical treatments. Detailed microstructural and electrical characterization within and across the joint was performed. Critical currents of up to 37 A within the joint region and 10 A through the joint region(at 77K) have been achieved.     

有机可焊性保护剂的现状与未来

文章概述了无铅化焊接用的五类表面涂（镀）覆材料应用情况，从总体的发展趋势上看，主要是HT—OSP取代HASL的问题。由于PCB高密度化的发展，HASL已经由高峰期走向衰老期，而高温型的HT-OSP开始由发展期走向高峰时期。     

无钎剂加压钎焊接头特性

阐述了微电子器件表面组装无钎剂加压钎焊新方法。利用研制的加压钎焊设备进行引线焊接并对试件进行了拉剪试验。试验结果表明，加压钎焊接合部强度高于普通软钎焊接合部强度的２倍。采用热电偶实时测量焊接劈刀强度，并利用电子探针对接合部元素的分布进行了分析。     

Velocity analysis of mechanisms with ball joints

A procedure is developed for analyzing velocities in spatial mechanisms with ball joints has been designed for practical computerization. The correspondence between the calculated velocities in a ball joint and the time changes of the physical displacements is clarified. The methodology is demonstrated using the RSPC mechanism which has seen commercial application as a washing-machine agitator mechanism.     

Structures and chromatographic characteristics of capsule-type silica gels coated with hydrophobic polymers in reversed-phase liquid chromatography

Summary Silicone polymer-coated silica gels modified with octadecyl and octyl groups (S/S-C₁₈, S/S-C₈), or “capsule-type silica gels” were developed as packing materials for reversed-phase liquid chromatography. They were obtained by coating the surface of totally porous silica gel with a homogeneous silicone polymer film, and thereafter modifying the coating polymer with octadecyl or octyl groups. Retaining the advantages of silica-based packings, they show strong resistance of alkali-like organic porous polymeric materials.     

2.5D封装结构回流焊过程热应力分析

对一种典型2.5D封装结构在回流焊工艺过程的热应力进行仿真。通过对比分析传统热力学仿真方法与基于生死单元技术的热力学仿真方法,研究了计算方法对热应力计算结果的影响。在相同参考温度下,由不同计算方法得到的硅通孔(TSV)转接板应力结果相差不大,从焊球应力结果可推测出,基于生死单元技术的热力学仿真方法考虑了残余应力的累积模拟更适合于回流焊过程的热应力仿真。研究了2.5D封装回流焊过程中参考温度的选择对计算结果的影响,选用最高参考温度作为各个组件的参考温度,通常得到TSV转接板的应力值偏大,模拟的结果会更加偏于激进。通过对2.5D封装结构回流焊过程进行热应力分析,对比分析了计算模拟方法和参考温度的选择对最终计算结果的影响。该方法同样可用于指导其他同类2.5D封装结构应力的计算和分析。     

航空电子产品焊接工艺验证方法研究

针对航空电子产品,阐述了一种相对完善的工艺验证方法,为航空电子产品制造商进行焊接工艺验证提供了指导。电子产品的类型多种多样,文章主要针对航空电子产品的特点,对其焊接工艺的验证方法进行探索和研究。     

一种用于开关电源的多模式振荡器

基于0.25 μm BCD工艺,设计了一种应用于开关电源的多模式环形振荡器,具有结构简单、三种模式可选、可修调的特点。电路通过模式切换生成可调电流的方式对电容充放电,产生不同频率的斜坡及方波信号。测试结果表明:在-40 ℃~125 ℃温度范围内,振荡器主振荡模式输出范围为483.9~518.6 kHz,与固定频率(500 kHz)的最大偏移率为3.72%,电阻频率调节模式输出范围为25 kHz~2.5 MHz,同步模式下可调同步频率范围为40 kHz~4 MHz。目前,该振荡器已被成功应用于一种DC-DC开关电源芯片中。     

电阻应变法用于密封电池内压变化的动态检测

报道了采用电阻变法动态检测密封电池内压变化的实验方法，并以镍氢电池为例，介绍了这一方法在研究电池工艺技术条件与电池充放电性能关系时的具体应用。