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991.
992.
引入环境参数、社会综合参数、行业参数,根据企业实际排污情况,探讨了运用污染指数法对污染企业实行定量化管理的方法。 相似文献
993.
土地适宜性评价中“主宜性”划分问题之探讨 总被引:3,自引:1,他引:3
在土地适宜性评价中,划分双宜或多宜性土地的主宜性是很有必要的。本文探讨了土地主宜性划分的原则、指标和方法,提出了分析土地主宜性的综合定量指标——“土地经济-社会适宜性指数”的概念,并以点苍山花甸坝为例,分析了这块土地的主宜性——适宜于耕作利用,利用方式是种植一年一熟喜凉作物。 相似文献
994.
Asbjørn Aaheim Hans A. Kristin Seip Hans M. 《Mitigation and Adaptation Strategies for Global Change》1999,4(1):61-81
Few studies on measures for mitigation of damage caused by man-made emissions to the environment have tried to consider all major effects. We illustrate the importance of an integrated approach by estimating costs and benefits of a proposed energy saving program for Hungary, originally designed to reduce CO2 emissions. The dominant benefit of implementing the program is likely to be reduced health damage from local pollutants. Also reduced costs of material damage and to a lesser extent vegetation damage contribute to make the net benefit considerable. Compared to the reduction in these local and regional effects, the benefits from reducing greenhouse gases are likely to be minor. Since local effects in general occur much earlier after measures have been implemented than effects of increased emissions of greenhouse gases, inclusion of local effects makes evaluation of climate policy less dependent on the choice of discount rate. In our opinion, similar results are likely for many measures originally designed to reduce emissions of greenhouse gases particularly in some areas in developing countries with high local pollution levels. Main uncertainties in the analysis, e.g. in the relationships between damage and pollution level, are discussed. 相似文献
995.
对银母寺铅锌矿床中钻孔、槽探和坑道工程控制的勘探剖面进行系统采样分析 ,研究原生异常的三维空间特征。经研究认为银母寺铅锌矿床的原生地球化学异常具有分带性 ,垂向分带序列 (自上向下 )为(Hg,As,Zn)→Cd→Cu→ (Pb,Ag) ,纵向分带序列为 :Cu→Pb→Ag→Cd→Hg→Zn ,横向分带序列 (从矿体中心向两侧 )为Pb←Zn←Cu、Ag、Hg、As←Cu→Pb→Ag→Hg→Zn→F。原生异常的分带指数具有明显变化规律且可用于预测同类型矿床的剥蚀程度 相似文献
996.
J. D. Wijnhoud Yothin Konboon Rod D. B. Lefroy 《Agriculture, ecosystems & environment》2003,100(2-3):119
In northeast Thailand, the sustainability of rainfed lowland rice-based systems, the dominant land-use system (LUS) in the region, is a concern for the welfare of the population in this relatively poor region. Poor soil fertility and low inputs are seen as major causes of this lack of sustainability. In this context, the assessment of nutrient budgets is seen as a powerful tool for the assessment of critical components of the sustainability of this particular LUS. Biophysical, socioeconomic, and management-related data on the farming systems were collected for 30 farms in Ubon Ratchathani Province, northeast Thailand. A relational database system (RDBS) was developed to manage and analyze the data. The RDBS includes a calculation procedure for the semi-automatic generation of partial nutrient balances. Partial nutrient balances are good indicators for some critical components of sustainability, and important for decision support on soil fertility management when considered with the additional factors that are required for a full nutrient balance.For the rice-based systems of 30 farms, mean partial balances were 12 kg N ha−1, 8 kg P ha−1, and 7 kg K ha−1 per year. Large variations in partial N, P, and K balances exist among different farms and, even more so, for different land utilization types (LUTs). The LUTs are distinct cropping system–management combinations that occur down to the subfield level. Many of the partial balances assessed were negative.Farmers manage nutrients for similar parcels of land in very different ways. This results in the observed large variation in partial nutrient balances, even for the same type of land use within the same farm. These results confirm the high inter-farm and intra-farm variability for partial balances of N, P, and K of several preliminary studies. Farmer interviews and field surveys revealed that different socioeconomic factors appear to be related with inter- and intra-farm variability in nutrient budgets. In addition, the socioeconomic component of the case study revealed that diversification of income sources, particularly off-farm employment, had a larger impact on household income than rice production. Furthermore, while many less well-off households had a greater reliance on rice production, many farms with high off-farm and non-rice farm income had a higher total production of rice.The nutrient balance approach, starting with partial nutrient balances, may become an important component of a dynamic and site-specific decision support tool (DST) for nutrient management, and a relational database of the form used in this study may become a key element. 相似文献
997.
气候舒适度对人居环境和人类活动具有深远影响,相关的评价模型/指数在建筑设计、城市规划、人体健康和旅游发展等领域有着广泛应用。体感分级标准作为气候舒适度评价模型不可或缺的关键环节,对模型效度有着重要的裁量权,也是实践应用中最终的度量衡工具。目前体感分级标准研究和应用中异地套用和局地实测的传统做法,在制定国家尺度普适性标准时遇到较大瓶颈。本文试图提出包含“定级—定名—定点—定宽”等基本环节的“季节锚点法”这一新的体感分级思路,并基于中国1981-2010年间814个基本(基准)气象站点的日值气象数据,以温湿指数和风效指数为例开展了实证研究。研究给出了“暑—热—暖—温—凉—冷—寒”这一针对中国区域的7级体感划分标准,并具体给出了温湿指数和风效指数在各体感等级上的阈值区间,进而在此基础计算评价了中国气候舒适期和不舒适期的时间长短、空间格局及其历时变化,得到一些有益发现。未来的研究可以进一步就细分人群、测试模型和区域差异等方面的体感分级标准开展更多深入探索。 相似文献
998.
999.
IntroductionThediversityamonginsectlifehistoriesmakesitdifficulttocomparetheeffectofachemical(orfactor)onthedevelopmentoftheseorganisms.Thediversityofbioassaysrangesfromthepopulationleveltothemolecularlevelandfrominvivotoinvitrostudies(Zhang ,1 993 ) .Differentparametershavebeenusedtostudyinsectgrowthinhibitionofmanychemicals.Forexample ,LD50 (thedosewhichcauses50 %mortalityinapopulation)iscommonlyusedtodeterminetheactivityofchemicalsthathaveacutetoxicity .Itcannotbeusedtothosechemicalsthatd… 相似文献
1000.
干旱综合防御集成技术机制及在华北冬麦区的示范应用研究 总被引:6,自引:1,他引:6
论文将底墒效应利用技术、土壤深松技术、秸秆覆盖技术、有限水分胁迫效应利用技术、喷施多功能防旱剂五项单项抗旱技术在冬小麦播前及各个发育阶段适时、适地综合集成,并给出了应用量化指标。于1998~2000年在河南、河北、山东省进行示范推广应用。结果表明:冬小麦干旱综合防御集成技术是通过各单项抗旱技术触发和优化冬小麦找水、增水、保水、节水、控水的五种水分利用机制,发挥了植物生理生态、土壤理化性状、土壤水库、麦田小气候效应和化学制剂喷施等多种防旱抗旱的效能,时间贯穿于冬小麦整个生育期,可实现持续防旱抗旱。集成技术具有比各单项技术更显著的增产、节水效果。在两个典型大旱年的情况下,集成技术使水分利用效率提高10.6%~53.7%,平均提高27.7%;小麦增产7.0%~42.3%,平均增产16.6%;每公顷增加纯收入490~1200元。 相似文献