Results 41 to 50 of about 7,369 (142)
为了研究地震载荷下圆柱型储罐内液体的晃荡特性,选用15种典型的地震信号,采用计算流体力学软件Fluent进行数值仿真,以探究地震的频率、频率成分、峰值速度以及峰值加速度对晃荡波高和水动压的作用规律。结果表明:① 地震主频是影响自由液面响应的主要因素之一,当其接近储液的一阶固有频率时,会激发强烈的非线性晃荡现象,工程中应添加减晃装置;② 波高与地震峰值速度呈较强的正相关,并且低频成分的地震信号激发的波浪较其它频率成分的地震信号更为剧烈;③ 水动压在储罐上部呈对流模式分布,主要受地震主频和频率成分的影响 ...
Xin Jin +7 more
doaj +1 more source
Abstract Background Diff‐Quik (DQ) staining is widely used in clinical practice for its ease of use and rapid results. However, its potential contamination remains a concern. Hypothesis/Objectives This study aimed to investigate DQ solution contamination in veterinary hospitals and identify factors affecting it through a questionnaire on stain usage ...
Minji Cho, Seulgi Bae
wiley +1 more source
通过对1台容量为200 kVA的S11-M-200/10型三相变压器的试验,分析比较了不同接线方式对频率响应曲线测量的影响。特别是对变压器外壳是否接地、注入电压的方向、非测试绕组的状态等的影响进行了深入的研究。研究表明:接线方式的不同可能导致频率响应曲线的巨大差异,某些情况下这些差异比绕组变形、变压器故障导致的差异更大。因此,笔者建议在进行变压器绕组频率响应曲线测量时应该保持各实验条件的一致。
王珊珊 +3 more
doaj
频率响应分析法是检测电力变压器绕组变形的常用诊断方法之一。近年来,频率响应分析法的检测流程趋向标准化,但寻求合适的算法对频响曲线数据进行量化分析仍需深入研究。文中将频响曲线数据的量化分析看作一个概率分类问题,提出了应用欧氏距离分析诊断变压器绕组变形程度和类型的新方法。研究结果表明,欧氏距离分析能够有效地对变压器绕组变形程度进行诊断,且与先前研究提出的数学指数方法相比,该方法对变形程度的诊断结果具有更高的线性度。同时,在检测频段分段后获取子频段的欧氏距离分布的基础上 ...
张重远 +6 more
doaj
Grazing bans improved vegetation but increased predator activity, reducing pheasant nesting success in Giant Panda National Park—highlighting trade‐offs in conservation policy. ABSTRACT Grazing has a profound impact on forest ecosystems and biodiversity.
Yifei Zhang +7 more
wiley +1 more source
Occurrences of dust storms and long‐distance movement of dust across landscapes is constantly increasing in south Asia. This dust is expected to have profound impact on vegetation health and sustainability as dust may contribute to nutrient budgets of the forest ecosystems, while it could impart various stresses to the plants.
Shree P. Pandey +2 more
wiley +1 more source
诸葛菜外植体再生力较强 ,可以作植物体细胞遗传学的实验材料 .以生长于两种不同MS培养基 (含或不含激素 )上的诸葛菜无菌苗下胚轴为外植体 ,研究不同外植体 ,不同激素组合和硝酸银对下胚轴高频率再生的影响效应 .结果如下 :激素的影响效应最显著 ,最适激素组合为MB1N ,植株再生频率高达 92 .51% .硝酸银对再生频率较高 ,激素组合 (6 BA +NAA)作用效应不明显 ,激素组合 (6 BA +2 ,4 D)只提高下胚轴再生频率 .不同外植体作用效应的差异只表现于培养基MB1N和MB2N中 ...
徐怀亮, 罗鹏, 陈艳红
doaj
Abstract Coastal storms are likely to increase in frequency and become even more damaging. An unresolved policy issue is whether current residents should receive federal subsidies through such programs as the Federal Flood Insurance Program or the FEMA disaster relief program that encourage thembe encouraged to rebuild in the same locations that have ...
Risa Palm +2 more
wiley +1 more source
Freshwater biodiversity in China is threatened by multiple anthropogenic factors, and while there are some reasons to suppose it may be possible to bend the curve of biodiversity loss, the variety of threats and their likely interactions with ongoing climate change provide little basis for optimism. For example, the historic overexploitation of Yangtze
David Dudgeon
wiley +1 more source
以型号为HSMS-282c的肖特基二极管为例,利用多物理场协同算法对其微波响应特性进行了计算.通过比较器件在有或无封装时对特定频率的响应情况,发现封装可使器件的耗散功率增加87%.本文还对比了肖特基二极管在不同频率微波激励下的平均耗散功率,发现器件的耗散功率在3.5GHz附近存在峰值.当二极管的工作频率高于3.2GHz时,耗散功率会随环境温度的增加而增加.研究结果对于半导体器件的微波效应研究具有重要的参考价值.
王昊, 陈星, 徐可, 黄卡玛
doaj

