变频恒压供水控制技术在泵站供水系统中的应用

初步讨论变频恒压供水的基本原理及其在泵站中的应用.通过介绍泵站供水工艺系统的组成、自动化及仪表系统的配置、变频恒压供水的控制原理及监控系统的构成等的泵站供水自动化控制工程实例说明变频恒压供水在泵站中的应用.     

地方环境管理信息系统的图形设计与微机实现

图形管理是REMIS的重要组成部分。本文从REMIS图形需求着手,概括图形功能,提出设计原则和实施环境,并介绍了在微机上实现的方法与步骤。     

基于元胞自动机的火源威胁下人员疏散模型*

为研究火源对人员疏散的影响,在现有场域模型的基础上进行扩展,结合元胞自动机提出1种考虑多出口吸引、人员从众行为与火源威胁3者耦合作用的场域疏散模型。此模型综合考虑心理和环境等因素,定量描述人员之间、人与环境之间的相互影响,将出口吸引、从众心理与火源威胁3个影响行人疏散决策的元素归一化,以静态场和动态场耦合作用确定的转移概率作为行人移动的准则。采用此模型,分别对火源位置、火源威胁范围扩散速度在疏散中的影响进行模拟研究。结果表明:模型在一定程度上能够反映火源威胁下行人的疏散过程,再现了行人躲避和趋众行为,能为火源威胁下行人疏散提供理论借鉴。     

计算机仿真方法在人群疏散影响参数研究中的应用

建筑物中的人群疏散受到灾场环境、建筑结构以及人员本身等诸多因素的共同影响,明确这些因素的影响机理与程度对人群的疏散安全具有重要意义.借助仿真软件buildingEXODUS,以某地铁车站为例,定量地研究了人员行走速度等参数对人群平均等待时间和人群平均行走时间的影响.结果表明:不同参数对人群疏散的影响存在着差别.即使是相同的参数,在不同类型的建筑中,其影响程度也可能发生变化.在此基础上,明确了出口涌流能力、疏散人数、行走速度和疏散准备时间四个对整体疏散时间影响显著的参数,通过对上述参数的控制,可以提高人群疏散的安全可靠性.     

A serendipitous, long-term infiltration experiment: Water and tritium circulation beneath the CAMBRIC trench at the Nevada Test Site

Underground nuclear weapons testing at the Nevada Test Site introduced numerous radionuclides that may be used subsequently to characterize subsurface hydrologic transport processes in arid climates. In 1965, a unique, 16-year pumping experiment designed to examine radionuclide migration away from the CAMBRIC nuclear test, conducted in the saturated zone beneath Frenchman Flat, Nevada, USA, gave rise to an unintended second experiment involving radionuclide infiltration through the vadose zone, as induced by seepage of pumping effluents beneath an unlined discharge trench. The combined experiments have been reanalyzed using a detailed, three-dimensional numerical model of transient, variably saturated flow and mass transport in a heterogeneous subsurface, tailored specifically for large-scale and efficient calculations. Simulations have been used to estimate tritium travel and residence times in various parts of the system for comparison with observations in wells. Model predictions of mass transport were able to clearly demonstrate radionuclide recycling behavior between the trench and pumping well previously suggested by isotopic age dating information; match travel time estimates for radionuclides moving between the trench, the water table, and monitoring and pumping wells; and provide more realistic ways in which to interpret the pumping well elution curves. Collectively, the results illustrate the utility of integrating detailed numerical modeling with diverse observational data in developing more accurate interpretations of contaminant migration processes.     

论电子阅览室管理中的安全问题与对策

随着现代信息网络技术的不断发展和广泛使用,使用电子阅览室查阅各种文献的读者迅速增加,电子阅览室的安全问题也愈发突出。从计算机及辅助设备的安全管理和维护、加强对计算机病毒的防治、加强对用户的管理等方面探讨了在网络环境下如何实现对电子阅览室日常的安全管理。     

LCA法在韩国环境标志产品评价中的应用研究

中国在大力发展和推广环境标志产品的同时,对环境标志产品的系统评价工作却显得薄弱,仍主要停留在能源消耗、污染物排放、废弃回收等单一因素或简单组合方式,缺乏客观性、全面性。因此借鉴国外有关先进经验,尽快建立系统的环境标志产品评价体系是很有必要的。韩国环境标志产品LCA评价的最大优点是将复杂、专业的数据转变为易于国民理解的简单形式,而有利于环境标志产品的宣传与发展。文章以LCA法在评价韩国环境标志产品中的应用为实例,系统说明其评价过程,并探讨其优势和不足,为中国相关工作的开展提供可借鉴的经验。     

电磁脉冲对计算机设备的易感性问题研究

电磁脉冲对电子设备威胁越来越严重,特别是对高性能、复杂的电子设备提出了更加苛刻的可靠性要求。就当前测试用电磁脉冲环境以及电磁脉冲的测试情况做了简要的介绍;在引述相关试验结果的基础上,通过比对不同的试验结果,从网络链路的后门耦合效应到计算机频率与电磁脉冲影响的关系等多个方面,分析并阐述了电磁脉冲条件下计算机设备的易感性问题。     

公路声屏障计算机辅助设计系统初步研究与实现

基于CAD二次开发技术的基本原理，步骤和方法，研究了声屏障计算机辅助设计系统的框架和结构，利用Visual Ba-sic的ActiveX Automaiton技术，初步开发了基于AutoCAD的公路声屏障计算机辅助设计软件，该软件在输入必要的环境条件和公路噪声的参数后，可自由进行公路交通噪声预测，评价和声屏的设计，并以表格的形式输出交通噪声预测值，以AutoCAD图形格式输出声屏障设计平面图，断面图，立面图等以及有无声屏障时交通噪声的空间等声级曲线图。     

Exploring the use of computer models in participatory integrated assessment – experiences and recommendations for further steps

Integrated assessment (IA) can be defined as a structured process of dealing with complex issues, using knowledge from various scientific disciplines and/or stakeholders, such that integrated insights are made available to decision makers (J. Rotmans, Enviromental Modelling and Assessment 3 (1998) 155). There is a growing recognition that the participation of stakeholders is a vital element of IA. However, only little is known about methodological requirements for such participatory IA and possible insights to be gained from these approaches. This paper summarizes some of the experiences gathered in the ULYSSES project, which aims at developing procedures that are able to bridge the gap between environmental science and democratic policy making for the issue of climate change. The discussion is based on a total of 52 IA focus groups with citizens, run in six European and one US city. In these groups, different computer models were used, ranging from complex and dynamic global models to simple accounting tools. The analysis in this paper focuses on the role of the computer models. The findings suggest that the computer models were successful at conveying to participants the temporal and spatial scale of climate change, the complexity of the system and the uncertainties in our understanding of it. However, most participants felt that the computer models were less instrumental for the exploration of policy options. Furthermore, both research teams and participants agreed that despite considerable efforts, most models were not sufficiently user-friendly and transparent for being accessed in an IA focus group. With that background, some methodological conclusions are drawn about the inclusion of the computer models in the deliberation process. Furthermore, some suggestions are made about how given models should be adapted and new ones developed in order to be helpful for participatory IA. This revised version was published online in July 2006 with corrections to the Cover Date.