Local government policies toward environmentally sensitive areas in British Columbia,Canada; Washington and Oregon,USA

While there has been sustained debate on the issue of provincial and state versus local government environmental planning, maintaining privately owned natural resources in the public interest is increasingly viewed as beyond the scope of local governments alone. This paper describes and compares province- and state-level mandates and options for local governments (i.e., city, county, or district) to regulate land uses of environmentally sensitive areas (ESAs) in British Columbia in Canada and in Washington and Oregon in the United States. We define ESAs as landscape elements or places that are vital to the long-term maintenance of biological diversity, soil, water, and other natural resources, especially as they relate to human health, safety, and welfare, both on-site and in a regional context. Underlying similarities are that all three jurisdictions legally express the need for land-use planning by local governments in managing ESAs. Although all three jurisdictions exhibit similar problems in their attempt to accomplish this, ESA planning by local governments is an optional process in British Columbia and Washington but mandatory in Oregon. Furthermore, actual processes prescribed by each of the three jurisdictions are quite different. The information base upon which local regulation of privately held ESAs depends is variable, both within and between the province- and statelevel jurisdictions. Other than for some specific water-related resources, standard definitions and inventory methods for ESAs are lacking, as is coordination among local governments or among the province- and state-level governments. This study concludes that there is a need for a regional environmental information system in the Pacific Northwest based upon an integrated and scientific approach toward ESA structures and functions.     

Management and valuation of an environmentally sensitive area: Norfolk Broadland,England, case study

Wetlands, like any other environmentally sensitive resource, require very careful evaluation. While it is accepted that all wetlands may be equally valuable in terms of maintaining global life-support systems, individual areas may be ranked according to their uniqueness or the irreplaceability of the resource should the wetland be developed. The various techniques available for evaluating the wetland resource in the development versus conservation conflict situation are critically assessed. Indirect appraisal via the opportunity cost method can generate valuable data which have contributed to the mitigation of such conflict situations.The Broadland, in Norfolk, England, recently designated an environmentally sensitive area (ESA), provides a case study example of wetland management. The search for an acceptable flood alleviation strategy for the ESA is examined in detail. The economic and environmental asset structure of the study area is examined at two levels. A basic screening system is applied to each of the identified flood protection planning units to enable the rank ordering of the units. A more detailed appraisal is then made of the value of selected units so that the cost-effectiveness of any planned expenditure on flood protection works can be assessed. Specific management issues and their likely effect on the environment, in terms of land use for example, are also addressed. The 1986 Agriculture Act marks a potential watershed in British conservation policy. The ESA policy encompasses a dual management strategy that attempts to stimulate compatible agricultural and conservation practices and activities. Other countries that still retain significant unspoiled wetland resources may find that preemptive regulatory government intervention in favor of conservation would help to avoid the worst aspects of the British experience.     

电液舵机系统的可靠性强化试验方案设计

以电液舵机为研究对象,根据其自身特点建立故障树,以得到系统的薄弱环节及主要故障模式。通过分析得到电液舵机系统的敏感应力,对可靠性强化试验应用于此类机电液一体化的产品进行了可行性分析,并设计了适用于电液舵机系统的可靠性强化试验方案。     

环境监测结果不确定度评定中灵敏系数的求解

本文介绍了重量法、容量滴定法、工作曲线法、气量法以及仪器直读式等方法,测定环境参数时,对其监测结果进行不确定度评定中,为计算标准不确定度所需的灵敏系数的求算公式.     

Single and joint stress of acetochlor and Pb on three agricultural crops in northeast China

In order to evaluate ecological risk of agrochemicals in agricultural environment, single and joint toxic effects of an important herbicide and a typical heavy metal on root elongation of crops were investigated. Seeds of the three crops including wheat （Triticum aestivum）, Chinese cabbage （Brassica pekimensis） and soybean （Glycine max） as the main crops in northeast China were exposed to acetochior as a herbicide and lead （Pb） as a heavy metal using the pot-culture method, and meadow brown soil as one of the main soils distributed in northeast China was applied in the investigation. The results indicated that the interactive effects of the two pollutants on root elongation of the three crops were very complicated although they had markedly significant （P〈0.01） linear interrelationships based on the regression analyses. When the concentration of added Pb^2＋ reached 200 mg/kg, acetochlor and Pb had an antagonistic effect on the inhibition of root elongation of the three crops. However, acetochlor and Pb had significantly （P〈0.05） synergic effects on the inhibition of root elongation when concentration of added Pb^2＋ was up to 1000 mg/kg. At the low concentration of added Pb, joint toxicity of acetochlor and Pb was more dependent on the concentration of Pb. Among the three crops, wheat was the most sensitive to the toxicity of Pb and Chinese cabbage was the most sensitive to the toxicity of acetochlor.     

基于防突工作流程的突出预测敏感指标体系构建方法

针对现有突出预测敏感指标确定方法存在的问题,基于瓦斯压力和瓦斯含量的联系,考察了临界压力和含量的对应关系,确定了瓦斯压力为杨柳煤矿10#煤层区域预测敏感指标,临界值为0.74MPa;采用实验室分析和现场验证相结合的手段,通过引入相对误差和迫近度等分析方法,确立了钻屑解吸指标Δh2为10#煤层局部预测敏感指标,临界值为180 Pa;结合我国目前防突工作基本流程,确定了突出预测敏感指标体系的构建方法,构建了杨柳煤矿10#煤层突出预测敏感指标体系。     

高灵敏雾化-火焰原子吸收光谱法测定烟尘中低含量铅

将高灵敏雾化技术用于火焰原子吸收光谱法，并测定了烟尘样品中的低含量铅，取得较满意的结果。当采样300L、样品溶液为25mL时，铅的检测限可达0.0012mg/m^3，方法标准曲线线性范围为0mg/L-1.0mg/L，相对标准差小于4.5％，加标回收率在87％-97％之间，并具有简便快速等特点。     

Thermal runaway criterion for chemical reaction systems: A modified divergence method

The chemical reaction in certain range of operating conditions may exhibit parametric sensitivity where small changes in one or more of the input parameters lead to changes in the output variables (eg. reaction temperature). The sharp rise of the reaction temperature is a critical behavior that may lead to runaway conditions. Thus, it is of vital importance to determine the critical operating parameters consisting of the parametric sensitivity region under the consideration of intrinsic safety. In this paper, a modified divergence criterion is proposed based on the trace of Jacobian matrix at the maximum temperature. The nonlinear differential equations describing the dynamic behavior of the chemical reaction is linearized locally in the vicinity of the equilibrium point by the small perturbation analysis. The relationship between the perturbation equation and parametric sensitivity of the reaction system is investigated. The critical values computed by the modified divergence criterion are compared with Morbidelli and Varma criterion (MV criterion), Adler and Enig criterion (AE criterion) and divergence criterion (Div criterion). The comparison demonstrates the validity of the new criterion. In addition, the critical explosion pressures of two kinds of hazardous chemicals are computed by the various critical criteria and compared with published experimental data. The results show that the modified divergence criterion could give smaller computational error compared with the previous criteria.     

华北代表性农田的蚯蚓群落与重金属污染指示研究

对鲁中地区农田环境有害化学物质对蚯蚓群体构成的影响进行了调查,并做了重金属毒理试验。普通农田的调查显示,棕壤农田有蚯蚓3科,6属,8种;褐土农田3科,5属,6种;潮土农田3科,6属,6种。调查、分析及毒理试验显示,潮土农田中暗灰异唇蚓、湖北远盲蚓、日本杜拉蚓3个种是适用于反应指示的重金属污染敏感种,赤子爱胜蚓、微小双胸蚓、威廉腔蚓3个种是适用于积累指示的重金属污染耐受性种。      

干旱生态敏感区水电站环境影响后评价指标体系研究

针对干旱生态敏感区水电站环境影响后评价的要求,设计备选指标集,采用频次分析法进行指标初选,采用专家咨询法进行指标精选,建立由4项二级指标、14项三级指标构成的干旱生态敏感区水电站环境影响后评价指标体系,采用层次分析法给每个指标赋予权重.将该评价指标体系用于某水电站建设的实例分析,结果表明,水电站运行以来总体上有利影响大...