舰船电子设备可维性设计对策

本文就目前舰船电子设备研制过程中存在的维修性问题,从结构设计角度探讨了舰船电子设备维修性的设计要求,以及提高舰船电子设备结构维修性和战备完好率的基本思路和对策。     

基于蒙特卡罗法的煤巷锚杆支护结构可靠性分析

应用工程结构可靠性理论,建立煤巷锚杆支护结构可靠性模型,针对其结构稳定性的极限状态功能函数高度非线性的特征,采用蒙特卡罗法在Matlab环境下直接产生服从各相应概率分布函数的随机变量数组计算其结构可靠度,编程过程简化,计算速度快,精度高,且不受极限状态方程非线性、随机变量非正态的限制,开辟了煤巷锚杆支护结构可靠度计算的新途径。建立了支护参数与可靠度的关系,指出了提高煤巷锚杆支护结构可靠度的方法和措施,为煤巷锚杆支护参数设计和优化提供了科学依据。     

斜拉桥支架法施工的自适应安全监测技术

介绍自适应控制的基本原理及其运用现状。根据斜拉桥的实际情况选用自适应控制形式,在主要部位埋设传感器和相关的测试仪器,明确监测时间并在实施中严格执行。依据实测结果对标高、应力、容重等参数按实际情况进行修正,得出施工过程中的受力状态,从而调整施工。算出主梁各节点理论施工预拱度变化曲线等数据并与实测值进行比较,反复修正。自适应法达到了仿真计算与实际施工过程保持一致的最佳施工控制效果。绥芬河斜拉桥的施工证明,自适应法是一种很适合斜拉桥支架施工安全监测的技术,值得推广应用。     

高性能纤维在个体防护装备上的应用现状及前景分析

高性能纤维是从化学纤维演化而来,是指耐高温、耐气候、耐化学腐蚀、质量轻、强度高、模量高的特种纤维材料。本文结合几种典型的高性能纤维的具体性能,对高性能纤维在个体防护装备上的应用现状及前景作了分析,旨在进一步推动高性能纤维在个体防护装备上的应用,从而在不同的使用情况下增强个体防护装备对人体的保护功能。     

颗粒物对污染源COD水质在线监测仪比对监测的影响

污水中的颗粒物是COD在线监测仪在比对监测时出现较大误差的原因之一,就颗粒物对COD在线监测仪是否产生影响以及影响效果进行了实验研究。研究结果表明,COD在线监测仪的预处理系统去除颗粒物会带来比对监测的误差,并且随着颗粒物浓度增加,误差增大;预处理系统过滤器尺寸也会对比对监测的误差产生影响,针对同一浓度水样,孔径越大误差越小,针对同一孔径过滤器则水样浓度越高误差越小。     

Application of fuzzy sets and cognitive maps to incorporate social science scenarios in integrated assessment modelsA case study of urbanization in Ujung Pandang, Indonesia

Decision–support systems in the field of integrated water management could benefit considerably from social science knowledge, as many environmental changes are human-induced. Unfortunately the adequate incorporation of qualitative social science concepts in a quantitative modeling framework is not straightforward. The applicability of fuzzy set theory and fuzzy cognitive maps for the integration of qualitative scenarios in a decision–support system was examined for the urbanization of the coastal city of Ujung Pandang, Indonesia. The results indicate that both techniques are useful tools for the design of integrated models based on a combination of concepts from the natural and social sciences. This revised version was published online in July 2006 with corrections to the Cover Date.     

空气和废气监测中H2S标液的选择

有2种不同方法制备的H2S标准溶液进行测定,结果表明,所得标准曲线斜率一致,因此,在实际工作中可对其灵活运用。     

Optimal Expansion Strategy for a Sewer System under Uncertainty

Because of fast urban sprawl, land use competition, and the gap in available funds and needed funds, municipal decision makers and planners are looking for more cost-effective and sustainable ways to improve their sewer infrastructure systems. The dominant approaches have turned to planning the sanitary sewer systems within a regional context, while the decentralized and on-site/cluster wastewater systems have not overcome the application barriers. But regionalization policy confers uncertainties and risks upon cities while planning for future events. Following the philosophy of smart growth, this paper presents several optimal expansion schemes for a fast-growing city in the US/Mexico borderlands—the city of Pharr in Texas under uncertainty. The waste stream generated in Pharr is divided into three distinct sewer sheds within the city limit, including south region, central region, and north region. The options available include routing the wastewater to a neighboring municipality (i.e., McAllen) for treatment and reuse, expanding the existing wastewater treatment plant (WWTP) in the south sewer shed, and constructing a new WWTP in the north sewer shed. Traditional deterministic least-cost optimization applied in the first stage can provide a cost-effective and technology-based decision without respect to associated uncertainties system wide. As the model is primarily driven by the fees charged for wastewater transfer, sensitivity analysis was emphasized by the inclusion of varying flat-rate fees for adjustable transfer schemes before contracting process that may support the assessment of fiscal benefits to all parties involved. Yet uncertainties might arise from wastewater generation, wastewater reuse, and cost increase in constructing and operating the new wastewater treatment plant simultaneously. When dealing with multiple sources of uncertainty, the grey mixed integer programming (GIP) model, formulated in the second stage, can further allow all sources of uncertainties to propagate throughout the optimization context, simultaneously leading to determine a wealth of optimal decisions within a reasonable range. Both models ran for three 5-year periods beginning in 2005 and ending in 2020. The dynamic outputs of this analysis reflect the systematic concerns about integrative uncertainties within this decision analysis, which enable decision makers and stakeholders to make all-inclusive decisions for sanitary sewer system expansion in an economically growing region.     

电子设备缓蚀剂对电子设备防护的应用研究

目的 研究DZ-1电子设备缓蚀剂用于电子设备防护的有效性.方法 参照MIL-PRF-81309G、MIL-L-87177A和Q/AVIC 03018中的试验方法,对自主研制的DZ-1电子设备缓蚀剂的性能进行全面评价.结果 DZ-1电子设备缓蚀剂没有闪点,在运输、储藏及使用过程中非常安全,使用性能良好,很容易去除,能够去...     

基于多态模糊BN的石化动设备故障概率定量风险评估

石化行业的压缩机、泵等动设备故障模式多样,故障概率的不确定性较大,常用的风险评估方法无法实现对石化行业动设备失效概率的定量评估,限制了设备安全管理的准确性和有效性.基于贝叶斯网络(BN)可定量计算复杂系统失效概率的特点,利用故障模式与影响分析(FMEA)方法获取动设备风险事件的因果关系,将其映射为BN,并利用BN中节点...