对高土壤电阻率地区牵引变电所接地技术的分析

从接地的实质出发,论述短路电流是接地电阻的控制因素。从土壤湿度、土壤温度、土壤结构类型等3个方面分析土壤电阻率对接地电阻的影响,提出高土壤电阻率地区变电所降阻措施,以及接地网设计的一些方法。     

公路路线方案比选的水土保持评价

结合《辽阳灯塔至沈阳辽中高速公路水土保持方案》编制中对路线方案进行的水土保持定量分析评价,提出了公路项目水土保持评价因素,验证了公路项目路线方案比选水土保持定量评价方法的可行性。     

Coastal Erosion and Its Social and Environmental Aspects in Tanzania: A Case Study in Illegal Sand Mining

Coastal erosion is one of the major coastal problems currently facing Tanzania. Several factors, including sea level rise, geology, and rapid coastal population growth accompanied by rapid increase of human activities that interfere with natural processes, have been linked to the problem. One of the human activities that have been well linked to the problem of coastal erosion is illegal sand mining along beaches, coastal streams/rivers, and other restricted areas. This causes localized accelerated/ severe coastal erosion and enormous environmental degradation and threat to coastal properties. Illegal sand mining is presently a big industry in Tanzania, employing many youths, and has become a social, economical, and environmental problem. Thus, it is a sensitive issue. The problem of illegal sand mining in Tanzania is revisited, and possible measures to control it are proposed. Measures that can help to reduce/eliminate illegal sand mining are: governments to address effectively the problem of unemployment and poverty in the society by formulation of effective policies, including the total liberalization of the labor market and reduction of the tax burden and regulations on potential employers; identifying alternative sources of sand that are environmentally safe to mine, of good quality, and easily accessible; launching well-focused mass education on the problem of coastal erosion; encouraging formation of legally registered associations of sand-miners that will work closely with relevant authorities to curb illegal sand mining; and strengthening of governance and improving research funding in the country.     

采用比例趋势分析法预测劳动力的需求量

受造船管理模式、生产场地资源等条件制约，造船企业生产计划安排不均衡的现象时有发生，由此引发的劳动力需求不均衡的现象在各个造船生产部门不同程度的存在，如何根据造船生产计划，有效地预测各生产阶段的劳动力需求，进行劳动力资源余缺调剂，一直是造船企业在努力探索的热门话题。本文试图运用数理统计的原理，借助计算机辅助工具（专业的软件），通过研究历史统计资料一实动工时的累积曲线，结合造船生产计划安排并考虑未来情况的变动，估计预测期内的累积曲线，以比例趋势法预测未来劳动力的需求量。     

An Assessment of Lake-Level Fluctuations on Beach and Shoreline Changes

Using data collected from May 1978 to November 1996, this article assesses the effects of fluctuating water levels on the beach and shoreline at the Northeast Beach, Point Pelee, Lake Erie, Canada. To compare the serial dynamics of lake levels with net shoreline positional changes and beach net sediment flux, the data are transformed to standard scores to deal with the differences in the units and in the scale associated with each variable. The results demonstrate that over the 18-year period, fluctuating lake levels are associated with shifts in shoreline position and the development of various aggradational and degradational states at the beach. A sustained rapid rise in lake levels will initiate an erosional sequence which will persist even with declining water levels. With a persistent decline in water levels the beach and shoreline will adjust very gradually from unstable, erosional states to an aggradational state. Other results emphasize that those beach sectors directly governed by artificial structures suffered disproportionately higher erosion during high-water levels. Coastal managers must, therefore, be cognizant of the fact that shore protection devices must be carefully designed in order to be effective against the influence of fluctuating lake levels.     

Exploring ‘weak signals’' as potential challenges in transport: an inventory of potential future technology developments

This article assesses the most likely technological developments in transport, not only by investigating current innovations but also by observing different approaches to confronting future developments. The article discusses technology forecasting and the meaning of environmentally sound technologies; some insights into technology development and the relevance of technological forecasting; the factors that influence technology development in transport; and, in this context, differentiation between exploration, expectation and forecasting. It goes on to identify, from four different perspectives, major developments of strategic relevance for the transport sector that might arise in the longer term. An assessment is made of the consequences of these observations for the implementation of innovations in transport.     

青藏线冻土地区接地问题探讨

在冻土地区，由于土壤电阻率的增大，电力设备的安全接地变得困难起来。介绍了在低温条件下对几种典型土壤以及各类降阻剂的电阻率特性进行实验研究的结果。给出了土壤电阻率随温度变化的规律。讨论了低温条件下降阻剂的使用方法和降阻效果。总结了国内外冻土地区接地设计的实验。对改善冻土地区接地安全性的方法提出了建议。     

土压平衡盾构施工中泡沫和膨润土改良土体的微观机理分析

由于缺乏外加剂和土体相互作用内在机理的研究,导致何种土体使用何种外加剂,如何调整比例,如何评价外加剂的使用效果等方面的研究相对滞后,在工程实践中往往依靠经验使用外加剂。作者通过三年的室内土体改良试验研究,提出了国内常用的两种外加剂和土体相互作用的内在机理,尤其对于盾构掘进中不同土质和土性应该使用何种类型的外加剂,文章基于微观试验给出了具有说服力的结论。     

浅谈土壤污染对园林植物的影响

主要论述土壤污染产生的根源，分析土壤污染给植物等产生的危害，以及对土壤的污染治理应采取的措施。使土壤得到净化，减少对园林植物危害作用。     

铁路建设项目经济评价信息系统的设计与应用

作者通过对铁路建设项目经济评价业务特点的分析,提出了利用计算机辅助经济评价的设计思想,并对运量预测、运营成本计算的算法作了详细讨论。