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41.
基于DPSIR概念框架的区域水土保持效益评价新思路 总被引:12,自引:0,他引:12
定量评价区域水土保持效益并得到综合质量指数,便于区域水土保持效益的纵向或横向比较,进而为水土保持技术的提升和区域生态环境建设的科学决策服务。DPSIR(driving force-pressure-state-impact-response)概念框架有助于全面分析水土保持的"驱动力"、"压力"、"状态"、"影响"和"响应",有助于理解水土保持社会、经济和环境各因素的作用过程以及彼此之间的因果关系。在介绍DPSIR概念框架的基础上,根据区域水土保持效益评价指标体系构建的主导原则,初步提出水土保持效益评价的DPSIR框架,进而提出水土保持效益评价从基础数据到综合指数集成的新思路。 相似文献
42.
根据河北省森林景观现状,运用景观多样性指数、分维数、景观破碎化指数等计算方法,分析河北省森林资源空间分布特征和存在问题,指出河北省森林景观保护和发展方向。 相似文献
43.
Cleome gynandra L., commonly known as cat's whiskers, is an erect, branched, annual herb, belonging to the family Cleomaceae. The species is thought to have originated in tropical Africa and Southeast Asia, and thereafter have spread to other tropical and subtropical countries in the Northern and Southern hemispheres. Cat's whiskers is a highly nutritious vegetable and also possesses numerous medicinal values, yet it is considered as a neglected and underutilized weed species (NUS) in most of the world. In India, C. gynandra is recorded in Assam, Gujarat, Kerala, Maharashtra, Rajasthan, Tamil Nadu, and Uttar Pradesh. There is no earlier report of this species in West Bengal, India. This report is the first record of natural occurrence of C. gynandra in West Bengal, India. The main objective of this report is to provide valid information about the invasion and naturalization of this species in a new geographical area supported with suitable data. Global distribution data of cat's whiskers was retrieved from available web resources and mapped using Quantum GIS software in order to validate the de novo nature of occurrence of this species in this region. 相似文献
44.
城市燃气管网的完整性管理 总被引:1,自引:0,他引:1
不同地区城市燃气管道的建设和运营管理水平存在很大差距,在保障燃气管网安全运行方面存在诸多问题,亟需针对燃气输配管网开展完整性管理。简述了国内外燃气管道失效事故和主要诱因,梳理了相关标准和规范。提出了燃气管网完整性管理理念:综合考虑影响管网完整性的所有因素,采取一体化管理模式,达到经济合理地保证管网安全有效运行的目的。建立了燃气管网完整性管理体系框架,包括管理体系和技术体系两个层面,贯穿应用于组织完整性、数据完整性和管理过程完整性之中,并保持一定的灵活性。完整性管理技术是实施燃气管网完整性管理的核心,通过有机结合形成了6步循环管理流程,持续完善各种完整性管理技术,可以提升燃气管网的本质安全和运营效益。 相似文献
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框架结构和剪力墙结构是较为常用的结构体系,本文对此类体系在施工图中容易出现的问题作了归纳,以期方便设计者及校审人查阅。 相似文献
47.
For tea,which is predominantly out-breeding woody perennial,genetic improvement through conventional approaches is relatively ineffective,slow and costly.As a potential tool to enhance the process,Tea Research Institute of Sri Lanka (TRISL) has integrated molecular biology to supplement the conventional program and is in progress.To date,a considerable progress has been achieved in the key areas such as genetic characterization and estimation of genetic diversity,isolation and characterization of EST and genomic SSRs,construction of SSR primers,construction of genetic maps and marker assisted selection and application of genomic approaches to understand the role of secondary metabolites disease resistance in tea and in this paper,a summarized version of above studies is presented. 相似文献
48.
《Plant Production Science》2013,16(1):24-30
AbstractTo evaluate the effect of inclination angle of the leaf on the leaf injury of rice by O3, we examined the effect of a 5-hr exposure to 0, 0.1, 0.3 cm3 m-3 O3, abbreviated as O0, O0.1 and O0.3, respectively, of the flag leaf using natural-light gas-exposure chambers. The middle portion of the flag leaf was set horizontally using lead weights (H plant) and it was compared with a non-treated, erect leaf (E plant). Gas exchange and chlorophyll fluorescence were measured immediately before, immediately after, and 1 and 3 d after the start of the exposure. The net photosynthetic rate, stomatal conductance and operating quantum efficiency of photosystem II (Fq’/Fm’) were decreased by the exposure to O3. Furthermore, the inhibitory effects of O0.1 and O0.3 on the H plants were severer than those on the E plants. The maximum quantum efficiency of photosystem II (Fv/Fm) in the leaf of H plants decreased immediately after exposure to O3. These results indicate that the weaker inhibitory effect of O3 on the erect leaf depends on the lower light intensity at the leaf surface, rather than the horizontal leaf position.Key words: Ascorbic acid, Chlorophyll fluorescence, Gas exchange, Leaf inclination angle, Oryza sativa, O3, Quantum efficiency. 相似文献
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本文通过对贵州山区复杂生态条件下农作物生产知识进行分析 ,提出“平台—框架—应用系统”的作物专家系统开发技术路线。其中对知识模型的建立、应用框架的开发设计和系统集成进行了详细的论述。其技术思想对在相应的生态条件下开发作物专家系统具有一定的借鉴意义 相似文献