Diurnal Variation Characteristics of Temperature and Water Content in Quicksand Surface Layer Under Different Protective Measures [PDF]
, 2023 [Objective] The variation of temperature and water content in a quicksand surface layer under different protective measures and their influencing mechanisms were investigated in order to provide a theoretical basis for vegetation restoration in a desert ...
Fan Yanwei, Shi Jinhong, Tang Xingpeng
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Numeral Study and Experimental Verification of Vent-Hole Type of External Cover on Differential Pressure Cooling [PDF]
, 2011 In order to solve the problem of cooling nonuniformity in forced air pre-cooling for vegetables and fruits,five vent-hole types were designed,and a physical model and a numerical model were established.The commercial software FLUENT was employed to ...
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Jianzhu Gangjiegou Jinzhan, 2022 预应力波纹腹板开孔组合梁力学性能不同于普通平腹板开孔组合梁。为研究腹板开孔对预应力波纹钢-混凝土组合梁抗火性能的影响，采用有限元软件ABAQUS对该类组合梁在高温作用下的力学性能进行非线性有限元分析，重点考察了预应力波纹腹板开孔组合梁的内力、跨中挠度以及破坏模式，并对其耐火性能进行了参数研究。结果表明：孔洞所在截面波纹腹板剪应力呈非均匀分布，临界状态时，该截面腹板基本丧失抗剪能力。预应力波纹腹板组合梁纯弯区开孔时，其破坏模式与无孔组合梁一致，均为弯曲破坏，孔洞基本不影响其跨中挠度与耐火性能 ...
周焕廷, 陈祥, 伍先兴
doaj
Research on rotary geosteering drilling technology and equipment in underground coal mine [PDF]
, 2022 In view of the limitations of directional drilling technology and equipment for underground gas drainage in coal mining areas, such as low degree of automation, low drilling ratio of target formation, slow drilling rate of rock formation, and small ...
Chao XU +7 more
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Research on temporal−spatial relationship between ground fracturing wells and underground drilling for substitution drainage of during extraction exhaustion period [PDF]
, 2022 In order to make use of the favorable extraction conditions formed by ground fracturing to carry out the underground borehole replacement extraction in the drainage exhaustion period of ground fracturing wells, and form the advanced treatment of ground ...
Jian HE +5 more
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Design of Left-handed Material Units and Their Antennas Based on Irregular/Asymmetric Structures [PDF]
, 2016 左手材料表现出很多奇特的电磁特性，使其在电磁学、微波和天线工程以及材料学等诸多领域拥有广阔的应用前景。目前，工作于微波频段的左手材料单元结构变化有很大一部分来源于经典的开口谐振环加金属线结构(SRR+Rod)，主要以规则、对称构型，一般双负频带窄、损耗大、尺寸也偏大，难以应用于有特殊性能要求和空间限制的微波器件。 本文针对目前微波频段左手材料所存在的以上缺点，提出了不规则及非对称两个系列的左手材料单元结构，即DNA形仿生结构和R形结构。在DNA形仿生系列中，首先讨论了双螺旋左手结构单元 ...
李坚
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Research on the Construction of the Confucius Institutes’ Performance Evaluation Index System [PDF]
, 2016 孔子学院已走过十年的发展历程，为更好地总结经验、探寻规律，进一步保障办学特色，提升教学质量，推动孔子学院取得稳步长足发展，通过建立严格的质量监控体系和科学的评估机制，定期开展对孔子学院的评估工作、实施质量认证无疑具有重要的战略意义。 本文在详细梳理孔子学院的宗旨定位、职能目标、主体功能以及实施绩效评估的文本依据等相关基本情况的基础上，就孔子学院的绩效评估特点从评估内容、评估对象和评估影响因素等三个方面进行了深入分析，据此，客观理性地评价了现行孔子学院绩效评估指标体系的价值性与局限性 ...
钟金玲
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, 2018 采用CFD数值模拟方法开展了基于桨尖开孔的旋翼桨尖涡抑制研究,重点分析了开孔位置、数目、直径等参数对桨尖涡结构和旋翼气动性能的影响。旋翼流场数值模拟通过求解旋转坐标系下的Navier-Stokes方程,采用格点格式的有限体积法,结合非结构重叠网格技术。无黏通量计算采用二阶中心格式加人工耗散,湍流模型采用Spalart-Allmaras模型。数值研究表明:桨尖开孔的位置对桨尖涡削弱效果的影响很小;开孔数目越多,孔径越大,桨尖涡的削弱效果越好;开孔旋翼的升力系数较无开孔构型小幅增加,而功率系数则较大幅度增加。
尤延铖 +4 more
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Response surface optimization design and electrochemical performance of sword shell-based carbon [PDF]
, 2021 With the attention to the world ecology and economy, people are observing the abundant, low-cost, and clean renewable energy from sun and wind. However, most of the renewable energy sources are intermittent and cannot meet the needs for applications ...
Chen, T +5 more
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Research on the Noise Measurement and Control of Wheeled Excavator and Its Application [PDF]
, 2015 除可靠性与经济性外，NVH（Noise,Vibration,Harshness）性能也成为评价轮式挖掘机品质的重要指标之一。90年代初的北美、欧洲和日本就有许多企业及学者开始对工程机械的振动噪声进行研究，并取得了很多成果。中国在该领域的研究起步相对较晚，很多国产工程机械的性能都落后于欧洲、美洲和日本的产品，尤其在振动噪声方面的差距更大。为了提高工程机械的舒适性，本文对轮式挖掘机的噪声测试与控制技术进行了研究。 首先 ...
李胜玉
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