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排序方式: 共有2264条查询结果,搜索用时 31 毫秒
481.
为在压回法气井压井计算中进一步贴合现场实际情况,提出新的压回法气井压井过程计算方法.在压井过程中,考虑压井液与侵入井筒的气体发生置换,导致井筒流体自上而下分布为液-气液2相-气-气液2相的实际问题,建立压井过程模型,并对井底压力的变化进行计算分析.结果表明:发生气液置换对压回法压井过程井底压力以及注入压力具有明显影响,... 相似文献
482.
The numerous formulated products which are introduced to the market consist of chemical ingredients that may cause various safety and health hazards to the consumers. Therefore, it is extremely important to practice a systematic methodology to formulate products with acceptable safety and health performances. This work presents an index-based methodology to assess the safety and health hazards of the ingredients during the early formulation stage of product design. Hence, new inherent safety and health sub-indexes are introduced to improve the current safety and health hazards that are needed in formulated product design. The inherent safety and health sub-indexes are assigned with scores based on the degree of potential hazards. A higher score indicates a higher safety risk or severe health effect, and vice versa. The proposed methodology will greatly assist the users to identify the adverse safety and health effects caused by the ingredients. Hence, it is pivotal to eliminate or reduce the safety and health impacts from product usage. A case study on common ingredients used in the formulation of paint is presented on this study to describe the proposed method. 相似文献
483.
David A. Wiedenfeld Allison C. Alberts Ariadne Angulo Elizabeth L. Bennett Onnie Byers Topiltzin Contreras-MacBeath Gláucia Drummond Gustavo A. B. da Fonseca Claude Gascon Ian Harrison Nicolas Heard Axel Hochkirch William Konstant Penny F. Langhammer Olivier Langrand Frederic Launay Daniel J. Lebbin Susan Lieberman Barney Long Zhi Lu Michael Maunder Russell A. Mittermeier Sanjay Molur Razan Khalifa al Mubarak Michael J. Parr Jonah Ratsimbazafy Anders G. J. Rhodin Anthony B. Rylands Jim Sanderson Wes Sechrest Pritpal Soorae Jatna Supriatna Amy Upgren Jean-Christophe Vié Li Zhang 《Conservation biology》2021,35(5):1388-1395
Some conservation prioritization methods are based on the assumption that conservation needs overwhelm current resources and not all species can be conserved; therefore, a conservation triage scheme (i.e., when the system is overwhelmed, species should be divided into three groups based on likelihood of survival, and efforts should be focused on those species in the group with the best survival prospects and reduced or denied to those in the group with no survival prospects and to those in the group not needing special efforts for their conservation) is necessary to guide resource allocation. We argue that this decision-making strategy is not appropriate because resources are not as limited as often assumed, and it is not evident that there are species that cannot be conserved. Small population size alone, for example, does not doom a species to extinction; plants, reptiles, birds, and mammals offer examples. Although resources dedicated to conserving all threatened species are insufficient at present, the world's economic resources are vast, and greater resources could be dedicated toward species conservation. The political framework for species conservation has improved, with initiatives such as the UN Sustainable Development Goals and other international agreements, funding mechanisms such as The Global Environment Facility, and the rise of many nongovernmental organizations with nimble, rapid-response small grants programs. For a prioritization system to allow no extinctions, zero extinctions must be an explicit goal of the system. Extinction is not inevitable, and should not be acceptable. A goal of no human-induced extinctions is imperative given the irreversibility of species loss. 相似文献
484.
Fay Madeleine Farstad 《环境政策》2019,28(6):997-1016
ABSTRACTThe implications of state size for the party politics of climate change are examined, and in particular its effect in facilitating or impeding cross-party consensus on the issue. This issue is explored through an in-depth, qualitative comparison of Australia and Norway, which are shown to be comparable in important respects yet differ in terms of their size and climate politics. Original primary data is presented from 44 interviews with policymakers and policy-shapers in both countries, which shows that, to the limited extent that state size moderates the parties’ behaviour, it is the countries’ geographical – not economic – size that matters. Institutional factors are found to play a more significant role, however, and the corporatist features of state-business cooperation, strong ENGOs and compensatory welfare arrangements are highlighted as particularly important. 相似文献
485.
486.
本文以玉山县宅前小流域开发治理规划为例,指出红壤地区小流域治理指导思想和应遵循原则,提出以山顶及坡度≥25°山坡营造防护林,坡度<25°山坡实行等高开垦为水土保持措施;同时兴修水利,建立山地灌溉体系,努力提高劳动者素质,加速区域经济发展,此小流域开发治理将为我国南方未开发的红壤地区充分利用自然资源提出一个典范。 相似文献
487.
N. K. Mazina 《Russian Journal of Ecology》2005,36(6):427-434
Multivariate factor analysis of the data on liver bioenergetics of mountain and forest voles has been performed. The specific features of tissue energy metabolism are best differentiated in the space of characters pertaining to the succinic acid oxidation system. The role of the dominant oxidation substrate in the structure of energy supply for the adaptation of tissue to a set of environmental factors in specialized and widespread species is discussed. 相似文献
488.
王如松 《中国人口.资源与环境》1997,7(3):11-14
本文提出了社会发展综合实验区建设的实质就是协调好人口、资源与环境间的生态关系,为了促进社会—经济—自然复合生态系统的持续发展,探讨了科技引导实验区生态建设的途径。 相似文献
489.
中国可持续发展指标体系建立的原则及结构 总被引:29,自引:1,他引:28
本文从中国的现实情况出发,借鉴了国外研究可持续发展指标体系的经验,提出了中国可持续发展指标体系的建立原则和结构。 相似文献
490.
对退耕还林中农民选择权认识的经济学分析 总被引:1,自引:0,他引:1
农户决策行为和反应机制无疑是考察项目可持续性的一个重要方面。本文应用微观经济学理论.结合退耕还林工程的实际情况.提出理论假说:贫瘠土地退出种植是经济发展到一定水平的自发结果。并根据三省遐耕还林的实际调查数据。采用计量模型对退耕还林农户选择权认识问题进行检验。研究结果表明退耕还林工程的可持续性还存在一定隐患,退耕还林工程不仅要和当地的经济发展紧密结合。在操作方法上还需进一步改进。 相似文献