Prediction of Undrained Sinkhole Collapse

Sinkholes are surface depressions or shafts resulting from the collapse of a submerged cavity in soil. The cavities that lead to sinkholes form as a result of underlying geology in limestone areas, or as a result of human activity such as mining or leakage from a sewer. The formation of sinkholes is often sudden and can lead to extensive damage and loss of life, especially in urban areas. Much of the literature on the subject of sinkhole formation is empirical in nature, often being associated with specific locations. This paper presents the results of a study, using numerical modeling, of the undrained stability of the submerged cavities that lead to sinkhole formation. Finite-element limit analysis techniques (using programs developed at the University of Newcastle) are used to obtain upper and lower bound values of a suitable load parameter, which bracket the exact solution. The results are compared to analytical solutions, both from literature and derived independently.     

应用杜邦财务分析体系对企业进行绩效评价

随着我国企业经营机制的不断完善,企业內部经营管理水平不断提升,越来越要求企业重视财务分析。通过对杜邦财务分析体系的介绍,结合实例应用杜邦财务分析体系对企业进行绩效评价,意在对各企业正确应用杜邦财务分析体系,揭示在经营目标发生异动时查明原因,并为企业采取措施修正指标指明方向。     

微量银的分析与测定

评述了近些年来国内外对于微量银的分析测定技术，包括分光光度法、电化学分析法、原子吸收分光光度法和发射光谱法等，对当前广泛应用的技术提出了改进的意见并对这类研究的发展前景做出展望。     

Economic Model to Optimize Underground Utility Protection

The need for better protecting our vital infrastructure from being damaged or destroyed has received increased attention since the terrorist attacks on September 11, 2001. The tragedy of having thousands of innocent people die before the eyes of an entire nation awakened people to the reality of “managed” attacks of unthinkable magnitudes. However, tragedies of a smaller scale are a daily occurrence but accepted as “collateral damage” of work in an unsafe environment. This paper presents a cost-benefit analysis to address the question of how much money should be spent in protecting underground utilities from damage. During the study of an actual incident it was found that the total costs of such accidents are vastly underreported because only costs for emergency responses and repair are tallied up. This paper makes the case that a comprehensive approach for assessing the total economic impact of such incidents on the public, business, and government is the critical stepping stone to a mathematical optimization of expenditure for damage prevention. In addition, the reader will quickly realize that the use of the presented optimization model provides theoretical underpinning for the engineering profession in its effort to better protect our critical infrastructure from terrorist attacks.     

城市燃气管网GIS系统的开发

随着我国天然气工业的不断发展，对于城市天然气管网的智能化管理已经作为一个全新的课题出现在燃气企业里。过去所使用的MIS系统（Management Information System），无论从效率、准确度、智能程度上讲，都已经不能满足目前城市燃气管网的精确管理。因此地理信息系统（Geography Information System，简称GIS系统）作为一种新的计算机管理系统应运而生，其主要特点是：有精确的管理、有标准的地图提供直接判断、空间关系与实物对应明确、管理直观。文章以企业对管理系统的需求以及技术可行性为出发点，阐述了GIS系统应具有的基本性能；同时结合燃气工程技术的发展，对燃气GIS系统做了应用开发研究；此外还对现阶段部分燃气GIS信息系统的不足做出了分析。     

PRO——一种新的地震资料处理方法

PRO(影像的参数展开)技术是由俄罗斯地球物理学家开发的一种崭新的地震资料处理技术。本文从PRO基本原理入手,简单介绍了PRO的速度分析原理。PRO速度分析和成像均以信号的椭圆展开和参数展开为基础,其中参数展开方法考虑波型转换、介质的横向不均匀造成传播速度的变化。该技术抛开了传统共中心点叠加的思想,从根本上解决了以CMP方法为基础的传统地震处理技术遇到的困难。通过模型与实例分析对比,PRO比传统CMP方法更优越。     

利用预曝光技术制备复合结构光纤光栅传感器

报道利用预曝光技术制备的复合结构光纤光栅传感器。提出利用预曝光技术使某一小段光纤的折射率变大,而后在预曝光部分和未曝光部分的交接处一次性写入光栅,即可得到具有两个透射峰的透射谱。实验研究了该复合结构光纤光栅在温度和应力传感上的应用。实验结果表明,利用该复合结构光纤光栅可以实现温度与应变的同时测量。     

CBGA组件热变形的2D-Plane42模型有限元分析

本文介绍有限元中的2D-Plane42模型在CBGA组件热变形中的应用，利用有限元的模拟CBGA组件的应变、应力的分布，通过模拟表明有限元法是研究微电子封装中BGA焊点、CBGA组件的可靠性的方法。     

山西引黄工程南干线7# 隧洞衬砌外水压力研究

本文采用综合修正系数取代规范建议的单一折减系数,用渗流场分析方法确定作用在引黄入晋南干线7#隧洞衬砌上的外水压力。由己知钻孔水位及泉水位反演出各地层的渗透张量及地表入渗强度求得初始渗流场。衬砌外水压力分析中考虑了衬砌混凝土的渗透性以及排水、灌浆等工程措施的影响。根据分析结果,提出了系统排水孔布置的建议,得出了在相应的排水减压措施下衬砌厚度由原设计35cm减至25cm,这一建议已被采用,取得了巨大经济效益。     

阜新市细河改造工程坝基渗漏计算及处理效果分析

阜新市细河改造工程由四座橡胶坝和两岸防洪大堤组成，由于堤(坝)基第四系冲洪积层广泛发育，存在渗漏同题。合理选择施工处理方案，是工程成功的关键。作者根据场区不同的地质条件环境条件采取有针对性的不同处理方案，既解决了防渗问题又缩短了施工工期，降低工程造价，取得了很好的经济效益和社会效益。