焊膏工艺性要求及性能检测方法

焊膏是SMT工艺中不可缺少的钎焊材料,广泛应用于再流焊中;它是由一定的合金粉末和助焊剂均匀混合而成的膏状体。主要对SMT中焊膏的组成及焊膏性能检测方法进行了简要分析。     

包装件压力试验机计算机测控系统

针对YE-50包装件压力试验机落后的测控系统，提出一种基于压力和位移闭环控制的计算机测控系统。根据测得的压力、位移和设定值，通过模糊控制输出驱动伺服阀实现了压力试验时的恒速控制和堆码试验时的恒力控制。并实时显示力——位移及应力——应变曲线。文中还对模糊控制器的实验整定方法进行了探讨。     

High dynamic range InP HBT delta-sigma analog-to-digital converters

To date, the development of multifunction multicarrier digital receivers for cellular base station and military communications applications has been limited by the demanding dynamic range requirements for the analog-to-digital converter (ADC). The use of oversampling delta-sigma modulators provides a promising approach to overcoming the dynamic range barriers Nyquist-rate converters face in the same applications. This paper discusses issues involved in the design of high-speed high dynamic range wide-band delta-sigma ADCs for such communications applications. Test results of prototype designs are also presented. The delta-sigma modulators described in this paper operate at sampling frequencies ranging from 1 to 2.5 GHz with center frequencies ranging from dc to 100 MHz, providing between 74 and 84.2 dB signal-to-noise ratio (12 and 13.7 bits) for bandwidths of 25 and 12.5 MHz, respectively. The loop filters are continuous-time low-pass and bandpass implementations of order 6 and 10, and were fabricated in an InP heterojunction bipolar (HBT) technology. A typical tenth-order design consumes 6 W of power and occupies a die area of 23.5 mm/sup 2/.     

胶性材料在混凝土坝裂缝处理中的应用

介绍了观音阁坝被埋水下6年越冬停浇面水平裂缝采用“粘贴T1密封胶及表面粘三元乙丙后锚固”的处理方案。结果表明,利用胶性材料处理运行中的重力坝迎水面裂缝,技术可靠,方法简单,经济合理。     

基于JSP技术的Web网站安全性研究

通过对基于JSP技术的Web网站的体系结构的介绍．从Web服务器安全、JSP脚本编程及数据库安全等几方面分析研究了web网站存在的安全问题，并探讨了web网站开发时应采取的安全措施。     

一种高性能的新结构IGBT

提出了一种低功率损耗的新结构IGBT.该新结构的创新点在于其复合耐压层结构,该耐压层包括深扩散形成的n型缓冲层和硼注入形成的透明背发射区两部分.虽然在正常工作条件下,该新结构IGBT工作于穿通状态,但器件仍具有非穿通IGBT(NPT-IGBT)的优良特性.该新结构IGBT具有比NPT-IGBT更薄的芯片厚度,从而可以获得更好的通态压降和关断功耗之间的折衷.实验结果表明:与NPT-IGBT相比较,新结构IGBT的功率损耗降低了40%.     

毗邻铁路大动脉排架式厂房拆除爆破

文章介绍了运煤车间爆破拆除工程的设计、施工经过及防后座的措施，对于复杂爆破环境的建筑物拆除有一定参考意义。     

低温脂肪酶产生菌的筛选、鉴定及其部分酶学性质

从南极乔治王岛冻土来源的76株低温细菌中筛选到13株低温脂肪酶产生菌，对其中的BTsl0022菌株进行鉴定。通过生理生化特征、16s rDNA基因序列的同源性和系统发育分析发现，菌株RTsl0022属于假单胞菌属(Pseudomonas)，但与已定名的假单胞菌有一定的差异，与未定名的Pseudomonas sp．PsB的亲缘关系最接近，故将其暂定名为Pseudomonas sp．BTsl0022。对该菌脂肪酶的酶学性质初步研究表明，酶的最适作用温度为24℃，对热敏感，60℃处理30min仅残留25％酶活性，酶的适宜作用pH范围在7．0～9．0，最适pH为8．0。     

A novel InP/InGaAs TEBT for ultralow current operations

A novel InP/InGaAs tunneling emitter bipolar transistor (TEBT) is fabricated and demonstrated. The studied device exhibits a very small collector-emitter offset voltage of 40 mV and an extremely wide operation regime. The operation region is larger than 11 decades in magnitude of collector current (10/sup -12/ to 10/sup -1/A). A current gain of 3 is obtained even if the device is operated at an ultralow collector current of 3.9 /spl times/ 10/sup -12/A (1.56 /spl times/ 10/sup -7/A/cm/sup 2/). Furthermore, the common-emitter breakdown voltage of the studied device is higher than 2 V. Consequently, the studied device shows a promise for low supply voltage, and low-power consumption circuit applications.     

铝薄膜CMP影响因素分析

提出了在碱性抛光液中铝薄膜化学机械抛光的机理模型,对抛光液的pH值、磨料、氧化剂浓度对过程参数的影响做了一些试验分析。试验结果表面粗糙度的铝薄膜所需的最优化CMP过程参数:硅溶胶粒径为15～20nm,pH值为10.8～11.2,氧化剂浓度为2.5%～3%。