Results 1 to 10 of about 579,834 (173)
Gaoya dianqi, 2021 真空开关开断电感性负载时,电弧重燃是产生严重操作过电压的根本原因。真空开关选相操作可以消除电弧重燃,避免严重的操作过电压。选相真空开关的机械稳定性是保证可靠选相操作的关键,对选相真空开关的机械稳定性进行在线检测,可及时发现和避免选相失效。文中提出两种选相特性在线检测方法:在选相真空开关的操动机构上设置一个和主触头动作稳定同步的辅助接点,用于触头刚分时刻的信号传感,可实现选相特性的在线检测和选相操作的自适应控制,及时发现选相特性劣化,避免选相失效;通过检测真空开关开断过程中的空间电磁波 ...
郑一鸣 +5 more
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Zhejiang Daxue xuebao. Lixue ban, 2005 选择阳离子聚丙烯酰胺类选堵剂，进行岩心模拟实验，研究不同岩心表面润湿性与化学选堵剂封堵能力之间的关系.表面润湿性强烈影响对水的堵塞率，水润湿性越强，对水的堵塞率越高，典型的亲水表面和亲油表面对水的堵塞率相差20% 左右；使用水基凝胶，水驱后的残余阻力系数(RRF)大于油驱后的RRF，水基凝胶使水相渗透率的降低比油相渗透率的降低多.对于润湿性相同，渗透率不同的天然岩心，选堵剂的堵水率大于85%，堵油率在20% 左右，表现出良好的选择性.
FANZhen-zhong(范振中) +1 more
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Gaoya dianqi, 2022 为了实现断路器选相合闸操作，对断路器机械稳定的性能进行研究分析，由于断路器运行时会受到各种因素的影响，致使断路器稳定性较差，对可能影响断路器稳定性的因素分类试验研究，得到了各类影响因素与断路器机械稳定性的变化规律，并根据研究结果，最终确定选相合闸断路器的SF6气压和选配机构的操作电压，并进行200次机械操作试验，合闸时间的正负偏差均在0.5 ms以内。选相合闸断路器顺利完成带电操作试验，且均在电压过零位置附件关合。选相合闸装置与断路器的结合，为超特高压断路器结构和空间布局的简化提供了可能性，同时 ...
姚灿江 +12 more
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Wildlife Letters, EarlyView.By comparing widespread surveys with randomly placed cameras to a protocol pairing detection dogs with cameras, we found that the detection‐dog‐guided camera survey had approximately 33 times greater detections with fewer camera nights and reduced survey costs. We recommend using detection dogs to identify areas to focus camera trapping. ABSTRACT Multi‐
Jenna B. Myers +5 more
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Zhejiang Daxue xuebao. Lixue ban, 2013 采用高效液相色谱研究了不同溶剂体系中褶皱假丝酵母菌脂肪酶(CRL)催化布洛芬乙烯酯水解反应的立体选择性.研究发现，在单一溶剂体系中Eyring曲线呈线性，在10~50 ℃的实验温度内均呈S选择性；在混合溶剂体系中Eyring曲线呈非线性，且观察到不同的转变温度(Tinv).研究还发现：在亲水性有机溶剂二氧六环/水均相混合溶剂体系中，Eyring曲线的Tinv处立体选择性E值为极小值，在疏水性有机溶剂异辛烷/水两相混合溶剂体系中，Tinv处E值为极大值，而在氯仿/水两相混合溶剂体系中，随着温度的变化 ...
WANGTing-ting(王婷婷) +3 more
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Functional Ecology, EarlyView.Read the free Plain Language Summary for this article on the Journal blog. Abstract Flowers with deep corollas are frequently associated with nectar robbing, a behaviour that often reduces pollen transfer and seed production. Robbing scars, however, may further affect plant reproductive success through rainwater entry into corolla tubes.
Wu Sun +6 more
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Zhejiang Daxue xuebao. Lixue ban, 2019 通过共沉淀法和两段焙烧的方式制备了丙烷选择氧化制丙烯酸的Mo1V0.3Te0.23Nb0.12SbxOy催化剂，并通过 XRD、XPS、H2-TPR、NH3-TPD 等表征手段探讨了Sb 元素的引入对催化剂相结构、表面酸碱性、氧化还原性等的影响。实验结果表明，适量Sb 元素的掺杂使得催化剂相结构中活性相M1 和M2 的相对量发生明显变化，催化剂表面酸性降低，氧化能力减弱，催化剂表面Mo6+和V5+物种量减少，提高了丙烯酸的选择性。当Sb/Mo 为 0.01 时，其丙烯酸选择性高达78.6%，得率可达48.
ZHANGWensheng(张文生) +2 more
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Comprehensive framework for assessing and optimizing existing research networks
Conservation Biology, EarlyView.Abstract Conservation, monitoring, and research networks, or collections of ecological research sites unified under a common mission of data collection or a research mission, are essential infrastructure for understanding large landscapes. However, most networks developed opportunistically over decades rather than through systematic design, creating ...
Alyson East +2 more
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Emerging applications of large language models in ecology and conservation science
Conservation Biology, EarlyView.Abstract Large language models (LLMs) mark a major development in artificial intelligence, with potentially transformative implications for ecology and conservation science. Built on advanced deep‐learning architectures, these models can support a wide range of tasks. We reviewed emerging applications of LLMs, drawing on the wider scientific literature
Christos Mammides +5 more
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Effects of restoration practices on biodiversity in temperate and boreal forests
Conservation Biology, EarlyView.Abstract Several restoration practices are used to mitigate and compensate for the negative effects of large‐scale forestry on biodiversity in temperate and boreal forests. A comprehensive synthesis of the benefits of these practices across taxa is missing. We conducted a systematic review and meta‐analysis on this topic.
Malin Tälle +2 more
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