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901.
本文叙述了国内外肉桂产品的市场、生产状况和发展趋势,分析了产业的投资经济效益,提出了加速发展云南肉桂产业的设想和实施建议。  相似文献   
902.
Reasonable production planning effectively ensures smooth operation. According to the analysis of the characteristics of steelmaking-continuous casting production process, a production planning method for steelmaking - continuous casting process based on time backward inference method and process simulation is presented. Production plan meeting certain criteria is rapidly gained by time backward inference method, and is regarded as input of simulation model in steelmaking process. Considering time randomicity in production process and transporting equipment restriction, production plan meeting more restrictive conditions, such as no equipment conflict, continuous casting, and etc, is acquired through simulating. It assures that the plan is carried out in practice. The instance demonstrates the feasibility of the method.  相似文献   
903.
生态系统管理途径是由生物多样性公约第四届缔约国大会根据生态系统中有机体与环境相互关系的基本规律所创建。它不仅是生物多样性保护和持续利用与保护区有效管理的重要指南,而且适用于规划综合农业的发展,改善人类生态环境质量,创造特殊的工程系统等。本文从理论分析和实际应用的角度简略地介绍它的基本含义和具体的操作,并阐明保护区怎样才能较好地实施生态系统管理途径,以期顺利地达到预期的目标。  相似文献   
904.
多效唑自20世纪80年代推出以来,备受广大研究学者的关注,多效唑的应用不仅对植株根、茎、叶等外部形态有影响,还有效地提高了植株的抗寒、抗旱等生理特性,其应用领域也不断扩展,从农业、果树逐渐发展到林业、蔬菜、园艺等各个方面,近年来更是取得了显著的研究成果。本文基于多效唑的作用机理,评述了多效唑对植株不同部位的作用效果及其应用领域的研究概况,结合当今日益严重的荒漠化问题,分析展望多效唑在沙地植物上应用的可能性和开发潜力,以期为提高沙地植物的生理生长特性、改进荒漠化治理模式提供科学依据。  相似文献   
905.
906.
907.
场地规划设计是建筑学与城市规划专业在工作中的重要内容,也是实际工程中的重要环节。笔者从规划设计角度,结合实际工作,阐述了场地施工图阶段设计的主要内容。  相似文献   
908.
Densities of aphids (Aphis gossypii and A. spiraecola) and mummified aphids at different phenological stages of a blueberry crop were estimated for the purpose of developing sampling plans. Our data set comprised 99 samples taken during the period 2006–2008 in four fields in Buenos Aires Province, Argentina. Estimation of population density based on the proportion of sample units infested by individuals was investigated. We also calculated the minimum number of sample units to estimate the density of individuals on buds and buds + flowers using enumerative sampling. The relative precision of both methods was compared. Moreover, an enumerative sequential sampling protocol was developed. The presence–absence sampling plan gave density estimates with large variances (as measured by confidence intervals and large standard errors). The aggregation of mummies was similar on buds and buds + flowers, so the required number of sample units for density estimates was the same. Relative precision of estimates was much lower for the presence–absence sampling than the enumerative sampling, even at intermediate densities. An enumerative sequential plan would be the most appropriate and useful method in management plans for aphids and mummified aphids in blueberries.  相似文献   
909.
中草药对奶牛乳房炎6种致病菌的抑菌效果观察   总被引:31,自引:1,他引:31  
用8味中草药煎剂及一个中草药复方制剂对奶牛乳房炎的6种致病菌进行抑菌实验,并测定了最小抑菌浓度(MIC)和最小杀菌浓度(MBC)。结果显示:金黄色葡萄球菌对连翘、复方、蒲公英中敏;牛棒状杆菌对连翘中敏,嗜热链球菌对瓜蒌极敏,对连翘、白附子、复方、木鳖子、天花粉中敏;产气荚膜梭菌对金银花、瓜蒌高敏,对复方、白附子、紫花地丁、天花粉中敏;乳房链球菌对瓜蒌、复方、金银花中敏;乳杆菌对所用药都低敏;瓜蒌、金银花、连翘对致病菌的MIC和MBC较低。进一步提取瓜蒌、金银花有效成分并与水煎剂对比,瓜蒌、金银花有效成分对6种致病菌均呈现良好的抑菌效果。  相似文献   
910.
Santelmann  M.V.  White  D.  Freemark  K.  Nassauer  J.I.  Eilers  J.M.  Vaché  K.B.  Danielson  B.J.  Corry  R.C.  Clark  M.E.  Polasky  S.  Cruse  R.M.  Sifneos  J.  Rustigian  H.  Coiner  C.  Wu  J.  Debinski  D. 《Landscape Ecology》2004,19(4):357-374
The contributions of current agricultural practices to environmental degradation and the social problems facing agricultural regions are well known. However, landscape-scale alternatives to current trends have not been fully explored nor their potential impacts quantified. To address this research need, our interdisciplinary team designed three alternative future scenarios for two watersheds in Iowa, USA, and used spatially-explicit models to evaluate the potential consequences of changes in farmland management. This paper summarizes and integrates the results of this interdisciplinary research project into an assessment of the designed alternatives intended to improve our understanding of landscape ecology in agricultural ecosystems and to inform agricultural policy. Scenario futures were digitized into a Geographic Information System (GIS), visualized with maps and simulated images, and evaluated for multiple endpoints to assess impacts of land use change on water quality, social and economic goals, and native flora and fauna. The Biodiversity scenario, targeting restoration of indigenous biodiversity, ranked higher than the current landscape for all endpoints (biodiversity, water quality, farmer preference, and profitability). The Biodiversity scenario ranked higher than the Production scenario (which focused on profitable agricultural production) in all endpoints but profitability, for which the two scenarios scored similarly, and also ranked higher than the Water Quality scenario in all endpoints except water quality. The Water Quality scenario, which targeted improvement in water quality, ranked highest of all landscapes in potential water quality and higher than the current landscape and the Production scenario in all but profitability. Our results indicate that innovative agricultural practices targeting environmental improvements may be acceptable to farmers and could substantially reduce the environmental impacts of agriculture in this region.This revised version was published online in May 2005 with corrections to the Cover Date.  相似文献   
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