对经济转型时期城市贫困问题的思考

在我国经济转型时期,不可避免地出现了城市贫困人口的增加,扶贫工作已经成为摆在我们面前的一项长期而艰巨的任务。本文就经济转型时期导致城市贫困人口增加的主要因素,针对当前城市扶贫工作的现状和问题,提出了一些具体的建议,以期进一步完善城市扶贫政策,以保障城市贫困群体的利益。     

水稻变异后代苗期耐低钾基因型的筛选

对30个来自富钾植物商陆DNA导入受体水稻品种粳85．5得到的性状稳定的变异后代材料在低钾营养液中进行培养,测定其三叶期幼苗K^＋吸收和H^＋释放速率．结果表明,在低钾溶液中,不同基因型水稻的心吸收和H^＋释放速率差异显著,两者之间呈极显著正相关,变异后代的K^＋吸收和H^＋释放速率均比其受体的高．结合考察30个水稻基因型分蘖期的株高、苗干重、根干重,对其进行耐低钾能力评价,这些基因型水稻被分为l级（高）、2级（中）、3级（非）耐低钾基因型3类．     

考虑溜桩效应的单桩基础承载特性数值模拟

为分析竖向和水平载荷作用下溜桩对钢管桩承载特性的影响规律,基于理论分析得到的溜桩区间数据,建立考虑溜桩效应的桩-土数值模型。结果显示：当单桩受到竖向载荷时,溜桩减小桩侧摩阻力,溜桩对钢管桩竖向承载力的影响较为显著;当单桩受到水平载荷时,溜桩条件下钢管桩弯矩大于无溜桩条件下的弯矩,说明发生溜桩会导致钢管桩产生更严重的弯曲变形;溜桩条件下的极限土抗力小于无溜桩情况。     

递归算法的递归子程序实现方法研究

对电磁轴承设计及其他工程实践中广泛存在的递归算法,提出采用递归子程序实现数值计算。在分析递归子程序特性的基础上,研究递归子程序设计方法。结合计算机硬件结构,详细分析递归子程序设计中的参数传递这一关键问题。给出了递归子程序实例,分析该程序的动态运行过程。     

可重构制造系统研究进展

可重构制造系统是面向客户定制生产方式的新制造理念,也是一种新的制造模式.文章回顾了可重构制造系统研究历史、概念、系统特点、关键技术等.重点论述了可重组制造系统国内外研究现状,最后指出了可重构制造系统的亟待研究的问题.     

Synthetic skin replacement for temporary wound coverage in eyelid surgery

BACKGROUND: Large uncovered defects of lid-skin which extend beyond the margin of the orbital rim frequently cause wound contracture and malposition of the lid. PATIENTS AND METHODS: Between April 1989 and October 1992 we have successfully used synthetic skin in severe cases of traumatic skin ablation (n = 3) and in complicated tumor surgery of the lids and of the medial canthal area (n = 14). Polyurethan foam material was used for temporary skin replacement (Epigard). RESULTS: The synthetic skin stimulated wound granulation and vascularization of the host area before final closure of the defect was achieved. No wound contracture occurred. CONCLUSION: Temporary bandage with synthetic skin is recommended if large skin defects can not be closed within 48 hours.     

Prevalence and determinants of house dust mite allergen in East German homes

BACKGROUND: In 1990/91, allergic sensitization to house dust mites (HDM) and other allergens was more prevalent in children from West Germany than from East Germany. OBJECTIVE: To test the hypothesis that low indoor exposure to HDM allergen in East Germany has contributed to this difference. METHODS: HDM allergen concentrations were determined in 634 East German dwellings shortly after the German reunification. RESULTS: HDM group I allergen (Der p 1 + Der f 1) levels in mattresses (median 2.16, geometric mean 2.07, maximum 278.9 microg/g dust) and carpets (median 0.41, geometric mean 0.48, maximum 96.3 microg/g dust) were within the range of levels determined in West Germany in other studies. One particular East German type of dwelling (light concrete buildings) was associated with lower mite allergen exposure, but only a minority of the population lived there. Coal heating, installed in the majority of dwellings before 1989, was associated with higher allergen exposure. Higher relative humidity (RH) was a main risk factor for higher Der p 1 exposure (odds ratio [OR] for exposure to > 0.05 microg/g dust on carpets: 1.4 [95% confidence interval (CI) 1.2-1.8] for + 10% RH) but not for higher Der f 1 exposure. Higher temperature was associated with a lower risk for elevated Der p 1 levels (> 0.05 microg/g dust on carpets): OR 0.6 (95% CI 0.5-0.8) for + 2 degrees C. CONCLUSION: Mite allergen exposure is not lower in East Germany than in West Germany. The data does not support the hypothesis, that low HDM allergen exposure in East Germany is a cause for the lower prevalence of HDM sensitization in East German children.     

基于故障树的系统可靠性仿真分析

如何推断系统的寿命分布,是目前可靠性工程领域的一个重要问题.文章应用改进的故障树分析法建立系统的仿真模型,利用蒙特卡洛法在计算机上产生等价于基本部件寿命实现值的随机数,将其代入到系统的仿真模型中,经过逻辑运算得到等价于系统寿命实现值的随机数.这个过程重复多次,便得到足够多的代表系统寿命的实现值的随机序列.在概率图中对随机序列进行统计推断,从而得到系统的寿命分布.此方法简单易行,计算结果精度高,对系统的可靠性分析有重要意义.     

Fire detection with low power fet gas sensors

Gas sensors based on hybrid suspended gate field effect devices are used for the detection of specific gases occurring in test fires. This sensor type can be operated with a power consumption < 1 mW and is therefore best suited for the use in fire detectors. Different floating gate FET (FGFET) sensors designed for the detection of CO, CO₂ and NO₂ were tested in standard test fires regarding EN54. Significant sensor signals were obtained for all test fires enabling a reliable and fast detection of fires. In addition, a separation of fire types is possible by signal evaluation combining signals of different sensors.