Results 21 to 30 of about 29,452 (216)
When and why to give shorebirds a head start
Conservation Biology, EarlyView.Abstract Headstarting is a translocation technique involving the hatching or rearing of wild eggs or young in captivity and the release of those individuals back to the wild at or before independence. It has been trialed as a conservation intervention for shorebirds over recent decades to improve the population trend of target populations by increasing
Lynda Donaldson +4 more
wiley +1 more source
The Study of Band Engineering and Polarization-induced Doping in AlGaN-based Deep Ultraviolet Light-Emitting Diode [PDF]
, 2016 Ⅲ族氮化物作为新一代半导体材料，具有宽直接带隙、高电子漂移率、高热导率、耐高温、抗腐蚀、抗辐射等优点，适合制作高频、高功率、耐高温和抗辐射的电子器件，比如AlGaN基紫外发光二极管。但是紫外发光二极管依然存在低量子效率、低光输出功率等问题，提高晶体质量和载流子注入效率是解决问题的两个主要思路。影响载流子注入效率的一个重要因素是内部极化场引起的能带弯曲，本文基于APSYS软件，主要围绕紫外LED的能带调控和极化诱导掺杂展开研究。 首先，本文回顾了紫外LED的发展历程，介绍了AlGaN半导体材料的结构和性质，
刘松青
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Conservation Biology, EarlyView.Abstract Recognition and engagement of Indigenous Peoples and local communities (IP&LCs) and other traditional knowledge (TK) holders in formal biodiversity governance remain limited, despite their significant contribution to the conservation and sustainable use of biodiversity through their knowledge, innovations, practices, and land stewardship.
Kinga Öllerer +8 more
wiley +1 more source
Effects of Treponema pallidum on THP-1 derived macrophage polarization [PDF]
, 2015 梅毒螺旋体（Treponemapallidum）是性传播疾病梅毒的致病菌，尽管有关T.pallidum的研究已经开展近一个多世纪，对其生物学及病原学特性有了一定的了解，然而对于T.pallidum致病机制的认识还处于起步阶段。巨噬细胞作为机体防御外来病原体的第一道防线，在对T.pallidum的识别、吞噬、抗原提呈、杀伤等方面均发挥着重要作用。随着对巨噬细胞研究不断深入，有学者将巨噬细胞分为两种不同的极化类型，即促进炎症发展的M1型巨噬细胞和在抑制炎症反应及组织修复等方面发挥作用的M2型巨噬细胞 ...
席亚
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Effects of political identity activation and inaccurate metaperceptions on attitudes toward wolves
Conservation Biology, EarlyView.Abstract Polarization between groups can undermine durable conservation outcomes. Activating group identities (i.e., an individual's sense of self derived from membership in a group) can exacerbate differences, especially when people hold inaccurate perceptions of their peers and rivals.
Alexander L. Metcalf, Justin W. Angle
wiley +1 more source
Gaoya dianqi, 2017 回复电压测量方法（return voltage measurement,RVM）能有效检测变压器固体绝缘的含水量,然而对于含有局部峰值点的回复电压极化谱难以给出明确的诊断结论。文中在扩展Debye模型基础上,仿真分析了模型参数变化对极化谱和主时间常数CTC、回复电压峰值最大值Urmax的影响规律,并提出将扩展Debye模型不同时间常数支路数作为新的特征量,最后验证了该特征量的可行性。仿真和试验结果表明:RVM极化谱前、中、尾3部分分别对应着油纸绝缘变压器油中偶极子转向极化 ...
吴广宁, 宋臻杰, 辛东立
doaj
Study on Corner-Fed Cavity-Backed Slot Dual-Polarized Antennas [PDF]
, 2015 为了在2.4GHz频段WLAN中实现具有方向性辐射的MIMO技术，采用背腔环形缝隙结构辐射元，通过倒置正交微带线激励，设计具有一定方向性的正交双极化天线结构。为提高端口间的隔离度和辐射场的极化纯度，在馈线正对的另一侧共面加载尺寸完全一致的接地或不接地导体带条。在此基础上，采用角馈的方法以期进一步改善天线的性能，并对各种可能天线形态进行对比分析。具体内容如下。 （1）对于边馈情形（即馈线位置垂直平分矩形导体腔表面的直角边），可以发现，没有加载导体条时，较佳隔离度对应的频带要高于阻抗工作频带，且相隔距离较大。
谢昇
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Geographic risks to functional groups of mammals and birds from habitat loss in Mexico
Conservation Biology, EarlyView.Abstract There is a need to quantify the impact of habitat loss due to anthropogenic factors on different aspects of biodiversity, such as functional trait diversity represented by functional groups (FGs). We developed a metric to assess the weighted risk of loss of habitat for 33 FGs of mammals and 36 FGs of birds in Mexico based on potential ...
Fernando Mayani‐Parás +4 more
wiley +1 more source
Research on Growth and Optical Properties of Semipolar III-Nitrides Nanostructures [PDF]
, 2016 III族氮化物半导体材料具有许多优良的性质，其纤锌矿结构晶体具有宽禁带，直接带隙，化学特性稳定，耐高温，质地坚硬等特点。近十几年对其的研究取得了瞩目的成果，商业价值巨大。具体应用包括显示，照明，存储，探测器，通讯，农作物生长照明，医疗健康，以及电力电子器件等领域。尽管如此，III族氮化物材料在发光器件应用领域仍然面临许多需要解决的问题，例如：电极化效应，高缺陷密度，光提取效率低，droop效应，GreenGap等。 为了改善上述问题，科研人员提出了多种研究方案 ...
曾凡明
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Conservation Biology, EarlyView.Abstract Achieving global conservation policy goals requires the ability to set and measure progress toward science‐based targets for biodiversity. The species threat abatement and restoration (STAR) metric was developed to enable actors to set science‐based targets for species.
Louise Mair +17 more
wiley +1 more source