沈阳市中水回用对策研究及前景分析

为了解决全市水资源严重短缺问题，缓解污水排放对生态环境造成的破坏，沈阳市在今后5～10a内将建成中水回用系统，使城市中水回用率达到50％。结合沈阳市中水回用现状，分析了目前全市中水供应能力及市场需求，进行了2010年相应指标的预测，同时探讨了沈阳市中水回用存在的问题和解决方法。     

人工神经元网络对水处理系统建模适应性的研究

针对水处理系统的特点和研究中的难点，引入人工神经元网络的理论和思想，提出了水处理系统的神经网络分析方法．通过建立基于ＢＰ人工神经元网络的臭氧生物活性炭系统的模型，具体地考察了人工神经元网络对水处理系统建模的适应性，使水处理系统的研究迈向智能化和控制化．     

环境承载力与环境扶贫

随着人类环境意识的觉醒与升华，引发了对自身生存环境的更深层次的思考。本文就环境承载力的内涵与外延以及它既会造成贫困又可解脱贫困的关键作用进行了研究和探讨。     

黄山风景区物质容量研究

系统地分析了旅游区物质容量与其子容量之间的关系,根据黄山区风景区客流空间负荷特点,认为北海游览区是黄山风景区物质容量的“瓶照”最低水桶板原则,合理计算了黄山风景区物质容量;详细探讨了扩大黄山风景区物质容量的若干途径。     

总量控制下环境容量产权交易及政府行为分析

利用经济学的原理，本文分析了环境容量的经济特点(不是环境容量产权交易的特征)，提出了环境容量产权交易的可行性和必要性。同时针对政府在环境容量产权交易中的作用进行了必要的分析。     

ECOSYSTEM DYNAMICS AND POLLUTION EFFECTS IN AN OZARK CAVE STREAM1

ABSTRACT: Subterranean ecosystems harbor globally rare fauna and important water resources, but ecological processes are poorly understood and are threatened by anthropogenic stresses. Ecosystem analyses were conducted from 1997 to 2000 in Cave Springs Cave, Arkansas, situated in a region of intensive land use, to determine the degree of habitat degradation and viability of endangered fauna. Organic matter budgeting quantified energy flux and documented the dominant input as dissolved organic matter and not gray bat guano (Myotis grisescens). Carbon/nitrogen stable isotope analyses described a trophic web of Ozark cavefish (Amblyopsis rosae) that primarily consumed cave isopods (Caecidotea stiladactyla), which in turn appeared to consume benthic matter originating from a complex mixture of soil, leaf litter, and anthropogenic wastes. Septic leachate, sewage sludge, and cow manure were suspected to augment the food web and were implicated in environmental degradation. Water, sediment, and animal tissue analyses detected excess nutrients, fecal bacteria, and toxic concentrations of metals. Community assemblage may have been altered: sensitive species‐grotto salamanders (Typhlotriton spelaeus) and stygobro‐mid amphipods—were not detected, while more resilient isopods flourished. Reduction of septic and agricultural waste inputs may be necessary to restore ecosystem dynamics in this cave ecosystem to its former undisturbed condition.     

INTEGRATING SERVICE‐LEARNING INTO WATERSHED MANAGEMENT PROGRAMS: OPPORTUNITIES AND CHALLENGES1

ABSTRACT: The objective of this article is to open a dialogue on integrating service‐learning into community based watershed management programs and to discuss opportunities and challenges that a service‐learning program presents to universities and communities. The article presents the concept and definition of service‐learning, and arguments concerning why institutions of higher education and university faculty and students should be involved with community based watershed management programs. The article describes a case study for developing a service‐learning program for watershed management at Virginia Tech and discusses lessons learned from the case study. The paper concluded that to make a service‐learning program sustainable, there should be a long term plan, regular and effective communication with the stakeholders, and some incentives for faculty and students for long term commitment to the community based watershed management programs.     

GROUND WATER NITRATE REDUCTION IN GIANT CANE AND FOREST RIPARIAN BUFFER ZONES1

ABSTRACT: Ground water contamination by excess nitrate leaching in row‐crop fields is an important issue in intensive agricultural areas of the United States and abroad. Giant cane and forest riparian buffer zones were monitored to determine each cover type's ability to reduce ground water nitrate concentrations. Ground water was sampled at varying distances from the field edge to determine an effective width for maximum nitrate attenuation. Ground water samples were analyzed for nitrate concentrations as well as chloride concentrations, which were used as a conservative ion to assess dilution or concentration effects within the riparian zone. Significant nitrate reductions occurred in both the cane and the forest riparian buffer zones within the first 3.3 m, a relatively narrow width. In this first 3.3 m, the cane and forest buffer reduced ground water nitrate levels by 90 percent and 61 percent, respectively. Approximately 40 percent of the observed 99 percent nitrate reduction over the 10 m cane buffer could be attributed to dilution by upwelling ground water. Neither ground water dilution nor concentration was observed in the forest buffer. The ground water nitrate attenuation capabilities of the cane and forest riparian zones were not statistically different. During the spring, both plant assimilation and denitrification were probably important nitrate loss mechanisms, while in the summer nitrate was more likely lost via denitrification since the water table dropped below the rooting zone.     

隔震建筑概念设计的基本问题

在隔震建筑的设计过程中应首先进行概念设计,在总体上把握隔震结构设计的主要方面。本文论述了隔震建筑概念设计的基本问题。在概念设计阶段,首先应在目标设计概念指导下,综合隔震建筑安全性与投资水平的平衡,确定建筑是采用隔震结构还是抗震结构。在进行隔震设计时,应根据输入地震动的加速度幅值和主频,建筑的允许加速度等值确定隔震结构的固有频率;应根据隔震系数和隔震层的允许位移合理确定隔震层总体刚度的范围。对隔震建筑的上部结构,应选择有利房型,合理布置结构,减小结构的不利地震反应。     

性能化防火设计方法的发展及其实施建议

针对目前各国性能化防火设计的发展状况，对性能化防火设计的产生背景、优点、基本组成和结构进行了初步论述，讨论了性能化防火设计未来的发展及其对我国消防体系的冲击。最后，参考国外一些成功的经验，对我国防火性能化设计的具体实施提出了一些有益的建议。