Results 31 to 40 of about 7,370 (165)
Shuitu Baochi Xuebao, 2001 采用变坡水槽研究了坡面流水动力学参数 (流态、流速、水深及阻力系数 )随流量和坡度的变化规律。结果表明 ,坡面流流态与水深密切相关 ,当水流深度小于 0 .316 cm时 ,坡面流呈过渡流 ,水深大于 0 .316 cm时呈紊流流态 ;当坡度为 5～ 2 5°、单宽流量为 0 .6 2 5～ 12 .5× 10 - 3m3/(s· m)时 ,坡面流平均流速和平均水深主要受流量控制 ,坡度的影响并不显著 ,可用简单的线性函数来模拟平均流速、水深与流量和坡度间的关系 (r2分别为 0 .89,0 .78) ;
张光辉 张光辉 卫海燕 刘宝元
doaj +2 more sources
Experimental Study on Frictional Pressure Drop Characteristics of Wire-wrapped Bundles in Transition Flow [PDF]
The investigation of frictional pressure drops in wire-wrapped bundles at low flow velocities is crucial for thermal-hydraulic studies of sodium-cooled fast reactor cores.
LI Hongrui1, , XUE Xiuli2, ZHOU Zhiwei2, ZENG Zehua1, LUO Rui1,
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Policy &Internet, Volume 17, Issue 2, June 2025.Abstract The COVID‐19 pandemic tested state preparedness across the globe and exposed cross‐sectoral deficiencies in infrastructure, resources and policymaking patterns. However, the prospects of the pandemic facilitating lasting institutional change have received limited attention.
Vassilis Karokis‐Mavrikos
wiley +1 more source
Shuitu Baochi Xuebao, 2017 为研究刚性植被覆盖与地表粗糙共同作用下的坡面流水动力特性，在室内开展定床水槽冲刷试验，研究陡坡（15°）条件下10组流量（0.33～1.95 m3/h）、5种覆盖率（0，0.5%，1.0%，1.5%，2.0%）、4种不同地表粗糙度（0.01，0.18，0.25，0.38 mm）的坡面流流速、流型流态、阻力系数等变化特性。结果表明：（1）水流流速变动范围为0.06～0.59 m/s，流速与植被覆盖率和地表粗糙度呈负相关关系（r＜-0.90），当植被覆盖率增加，流速随流量增加的增幅降低 ...
刘文剑 +3 more
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Rope Elastic Influence and Aerodynamic Parameter Measurement in Wind Tunnel of WDPSS-8 [PDF]
, 2016 风洞试验是获取飞行器性能参数的重要手段，相对于传统的硬式支撑方式， 绳索牵引并联机构作为一种新的支撑系统，具有惯性小、结构刚度高、负载能力 强、对流场影响小等优点。本文针对绳索牵引并联支撑系统在风洞试验中的应用， 重点分析了牵引绳弹性形变对飞行器模型运动位姿精度的影响及误差补偿策略； 结合课题组建立的原理样机进行了风洞试验，对利用绳拉力解算气动参数的方法 进行了理论分析和试验验证，主要工作及成果如下所述。 首先，描述了系统构成及应用参数，建立了运动学和动力学模型，并对机构 进行了刚度分析 ...
马少宇
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Using camera traps to enhance community‐based management of subsistence hunting in the Amazon
Conservation Biology, Volume 39, Issue 3, June 2025.Abstract Community‐based management and monitoring of biodiversity has emerged as a cost‐effective strategy for providing credible data, informing decision‐making, and empowering local communities in resource governance and management. However, the establishment of community‐based management of subsistence hunting in the Brazilian Amazon has been ...
Ricardo Sampaio +3 more
wiley +1 more source
Multi-objective optimal design of airfoil based on multi-island genetic algorithm [PDF]
ObjectivesA multi-objective optimization algorithm is proposed to address the problem of the complex operating conditions of large horizontal axis hydraulic turbine blades.
Lin CUI +5 more
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Including the urbanization gradient in people‐centered wildlife conservation in Amazonia
Conservation Biology, Volume 39, Issue 3, June 2025.Abstract Conservation policy in the Amazon traditionally focuses on rural areas, overlooking the socioecological roles of urban populations. This oversight can hinder sustainability by neglecting rural–urban connections. We compared the prevalence and quantity of wild meat consumed, bartered, and traded commercially in rural, peri‐urban, and urban ...
Lísley P. Lemos +3 more
wiley +1 more source
Shiyou jixie, 2012 鉴于目前对割缝筛管的双梯形缝局部阻力损失研究较少的状况，运用渐扩管流动阻力理论，提出基于阻力系数的双梯形缝隙的设计方法，并分别用理论计算与仿真计算方法进行了相应的研究对比。分析结果表明，双梯形缝总阻力系数随扩散角的变化而变化，对于给定入口雷诺数与合适转折宽度的情况下，总存在最佳扩散角使总阻力最小；最佳扩散角随入口雷诺数的不同而不同，在常见的雷诺数范围内，雷诺数越大，最佳扩散角越大。
李夯, 刘永红, 王亚洲, 马建民
doaj
, 2018 由于地域及环境的限制, 高速铁路采用多种路基结构如平直地面、不同高度路堤、高架桥等,当列车运行在路堤及高架桥上时,车体周围的绕流流场比平直地面更加复杂。在强横风的作用下,不同的路基结构上的高速列车横风气动特性存在明显差异,不合理的路基结构将影响列车的横风安全性。同时列车结构复杂,转向架、受电弓等都对列车的流场特性有重要作用,过于简化的短编组列车外形不能够精细反映列车的真实气动特性。为研究典型路基结构对高速列车横风气动特性的影响,以9编组动力集中型高速列车实车为研究对象,考虑风挡、转向架、受电弓等细节特征,
刘雯 +5 more
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