The effect of Ga on internal friction of pure Al before and after deformation

The grain boundary internal friction of pure Al and the same Al doped with different amounts of Ga (10, 50 and 410 ppm) was measured before and after high temperature deformation at two different modes (static tensile creep and cyclic reverse torsion). It was found that without deformation, the smaller amount of Ga (10 and 50 ppm) slightly increases, but the larger amount of Ga (410 ppm) obviously increases the activation energy. After tensile creep, the peak height for Al-10 ppm Ga and Al-50 ppm Ga decreases to a lower level, but keeps at a higher level after cyclic torsion, than that for pure Al and Al-410 ppm Ga. The results are interpreted in terms of perturbations in the grain boundaries due to slip and grain boundary roughening for stationary boundaries and an enhanced sliding by grain boundary migration. Migration and roughening are promoted by Ga contents up to 50 ppm while the effects are diminished by higher amounts of Ga. This is consistent with previous observations that smaller amounts of Ga increase the grain boundary mobility in pure Al.     

HDI—LineCard制造技术与应用初探

文章以设计、制造、组装的顺序对HDI-LineCard产品现状进行叙述。重点从对准度、通孔/盲孔成型、通孔/盲孔的金属化以及可靠性方面讲述了HDI-LineCard产品制造的着力点,文末对未来HDI-LineCard的技术发展趋势进行了展望。     

Recognising partially occluded objects by rigid body relaxation matching

By representing 3D objects by a rigid-body model (RBM), application of probabilistic relaxation to satisfy the embedded spatial constraints in the RBMs for recognising partially occluded objects using range data was investigated. A computer simulated data set was used to illustrate the effectiveness of the proposed procedure.<>     

基于LabVIEW的超声检测虚拟仪器开发

介绍了在LabVIEW开发平台下开发超声检测虚拟仪器系统的过程,并给出基于VC++6.0环境编写数据采集卡动态链接库(DLL)驱动程序,通过LabVIEW的CLF模块调用这个DLL来实现数据采集.该系统不仅能实时显示采集的超声波信号,而且能够对焊缝的缺陷进行定位、定量和定性分析,实现了超声检测的数字化、图像化、智能化、自动化.     

Biological monitoring of cadmium exposure and renal effects in a population group residing in a polluted area in China

In an area of China, not previously studied in detail concerning cadmium pollution and possible adverse effects on the kidney of exposed populations, concentrations of cadmium in urine as an indicator of renal accumulation of cadmium was studied and related to indicators of renal dysfunction in order to examine if a relationship could be documented. Cadmium concentrations in urine were analysed by graphite furnace atomic absorption spectrometry and urinary beta-2 microglobulin (UBM) and albumin (UALB) were measured as indicators of renal dysfunction, Rice samples and urine samples were obtained from three areas in Zhejiang province, China, representing a highly exposed area, a medium exposed area and a control area, respectively. Cadmium concentrations in rice were 3.70, 0.51 and 0.072 mg/kg for the heavily, medium polluted areas and the control area, respectively. Cadmium concentrations in urine (geometric means) were 10.7, 1.62 and 0.40 micrograms/l in the high, medium and control areas respectively. There was a clear increase in UBM and UALB in the heavily exposed group in comparison to the control group and a slight increase in the medium exposed group. There was a statistically significant dose-response relationship between cadmium in urine and beta 2-microglobulin excretion in urine, which is similar to what has previously been reported in other countries. The findings constitute the first report concerning a dose-response relationship in this population group in Zhejiang province in China.     

地下各种压力之间关系式的修正

目前在钻井工程中普遍采用的地下各种压力之间的关系式是不严格的，研究把岩石视为多孔介质，从多孔介质的角度出发，重新建立上覆岩层压力，孔隙流体压力、基岩应力之间的关系式，该式包含了岩石作为多孔介质的一个重要参数孔隙度Φ。     

葠窝水库坝体裂缝的治理

1971年　窝水库坝体存在210余条裂缝，1985年发展到800余条，总漏水量约1149m3／d．为治理坝体渗漏，1978年前曾采用过水泥灌浆和丙凝、环氧等化学灌浆对裂缝进行过处理，同时上游面采用过环氧橡皮涂贴等处理试验，效果均不明显．1981年普查，这些裂缝不但在数量上有所增加，而且长度、宽度、渗水量等问题也较前严重．因此于1985年进行了加固除险工程．治理措施渗漏治理最好位置在上游面，由于多数建筑物要带水施工，施工难度大而且投资也大．背水面施工由于水还在混凝土内部，同时由于冻胀重新产生裂缝而治不了本．因此在治理过程中采用“…     

An economic feasibility study for a broadband virtual pathSONET/ATM self-healing ring architecture

A ring architecture that uses the asynchronous transfer mode (ATM) virtual path (VP) concept to reduce the SONET ring cost in terms of bandwidth management is discussed. The add-drop multiplexer (ADM) proposed for VP ring architectures can evolve from existing SONET ADMs by replacing the STS-3 termination cards by the ATM STS-3c line cards. Existing standard self-healing schemes and protocol SONET rings can be applied to proposed ATM/SONET VP rings. A case study based on a BCC (Bellcore client company) ring network and the sensitivity analysis suggests that the proposed ATM VP ring architecture may be a cost-effective option for implementing the distributed ring grooming system at the DS 1 level. The proposed VP self-healing rings are not only used to carry existing DS 1 and DS 3 service, but can also be used to more cost-effectively consolidate switches for public-switched services and for SMDS, frame relay, and FDDI in metropolitan areas     

医用微型温度传感针的研制

介绍一种采用微细加工技术,将热敏电阻微型化制作的针体外径φ0.40mm的微型医用温度传感针的设计、结构、工艺、实验及临床应用,并展望其发展前景。