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论述中国工笔花鸟画的表现手法在陶瓷新彩装饰的结合运用,不同技法的结合追求具有独特的审美效果。 相似文献
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鸟类目标雷达散射特性研究逐渐受到重视。首先对鸟类目标的雷达散射特性进行了理论分析,利用实验室数据构造的理论统计模型,估算单只鸟的雷达散射截面(RCS )量级,然后详细介绍了在实验室对鸟类雷达散射截面进行测量的方法和测试结果。 相似文献
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Sandbars are an important aquatic terrestrial transition zone (ATTZ) in the active channel of rivers that provide a variety of habitat conditions for riverine biota. Channelization and flow regulation in many large rivers have diminished sandbar habitats and their rehabilitation is a priority. We developed sandbar‐specific models of discharge‐area relationships to determine how changes in flow regime affect the area of different habitat types within the submerged sandbar ATTZ (depth) and exposed sandbar ATTZ (elevation) for a representative sample of Lower Missouri River sandbars. We defined six different structural habitat types within the sandbar ATTZ based on depth or exposed elevation ranges that are important to different biota during at least part of their annual cycle for either survival or reproduction. Scenarios included the modelled natural flow regime, current managed flow regime and two environmental flow options, all modelled within the contemporary river active channel. Thirteen point and wing‐dike sandbars were evaluated under four different flow scenarios to explore the effects of flow regime on seasonal habitat availability for foraging of migratory shorebirds and wading birds, nesting of softshell turtles and nursery of riverine fishes. Managed flows provided more foraging habitat for shorebirds and wading birds and more nursery habitat for riverine fishes within the channelized reach sandbar ATTZ than the natural flow regime or modelled environmental flows. Reduced summer flows occurring under natural and environmental flow alternatives increased exposed sandbar nesting habitat for softshell turtle hatchling emergence. Results reveal how management of channelized and flow regulated large rivers could benefit from a modelling framework that couples hydrologic and geomorphic characteristics to predict habitat conditions for a variety of biota. Published in 2011 by John Wiley & Sons, Ltd. 相似文献
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A comparative evolutionary psychological perspective predicts that species that recurrently faced similar adaptive problems may have evolved similar psychological mechanisms to solve these problems. Sperm competition provides an arena in which to assess the heuristic value of such a comparative evolutionary perspective. The sperm competition that results from female infidelity and polyandry presents a similar class of adaptive problems for individuals across many species. The authors first describe mechanisms of sperm competition in insects and in birds. They suggest that the adaptive problems and evolved solutions in these species provide insight into human anatomy, physiology, psychology, and behavior. The authors then review recent theoretical and empirical arguments for the existence of sperm competition in humans and discuss proposed adaptations in humans that have analogs in insects or birds. The authors conclude by highlighting the heuristic value of a comparative evolutionary psychological approach in this field. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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A. Redfearn BSc. PhD. M. May. BSc MSc D. Roberts BSc PhD 《Water and Environment Journal》2004,18(3):139-143
The paper presents an ecological risk-assessment methodology which (a) addresses surface-water exposures to aquatic mammals and birds, and (b) accounts for long-term accumulation and biomagnification of pollutants. The methodology has been adapted from those developed in the USA for compliance with US Environmental Protection Agency requirements, and combines predicted or measured surface-water concentration data with information on the natural history of wildlife species and chemical-specific bioaccumulation factors, to determine whether estimated exposures would exceed toxicological criteria. Whilst the methodology is applied to metals in leachate discharges from landfill sites, the general approach is applicable to other industrial sites. The approach could provide the basis for a shift towards more numerical risk-based ecological assessments in a wide variety of contexts. 相似文献
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输电线路鸟害分析及其防治对策 总被引:5,自引:0,他引:5
通过鸟类的习性及其分布规律的分析研究,阐述了输电线路鸟害事故的特点及其原因,并结合工作实际提出了一些有针对性的防治对策,对解决输电线路的鸟害问题起了积极的作用,并期望对相关部门提供参考。 相似文献
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根据国内近几年的统计数据表明,涉鸟故障造成的输电线路跳闸次数已超过总数的10%,鸟类活动已经成为仅次于雷击、外力破坏的第三大输电线路跳闸原因。对架空输电线路涉鸟故障相关鸟种和习性进行了研究分析,确认不同涉鸟故障类型及其鸟种和区域分布情况。根据涉鸟故障的统计分析,发现涉鸟故障主要发生在3—7月的农田或邻近水源低海拔地区。同时,涉鸟故障发生的概率还与杆塔的结构型式、排列方式和相别有关。在对涉鸟故障试验研究和仿真计算的基础上,得到了不同电压等级下不同涉鸟故障的防护范围,并对比不同防鸟装置的性能和优缺点,提出了合理的防治措施。 相似文献