Results 41 to 50 of about 652 (99)
Shuitu Baochi Xuebao, 2008 研究测定了不同高度、不同规格的9种带状沙柳沙障对风速、地表粗糙度和近地表输沙率的影响。结果表明:带状沙柳沙障的防护效益与沙障的高度和规格有直接关系。行数越多、带距越小,防护效果越好,但是成本也越大。发挥最大成本效益的带状沙柳沙障规格为三行一带,带高1.5 m,行距1.5 m,带距10.5 m;其次为两行一带,带高1.5 m,行距1.5 m,带距7.5 m;再次为三行一带,带高1 m,行距1 m,带距7 m。一行一带的沙障,不管高度如何,成本效益都不理想。
王翔宇 +5 more
doaj
Measurement of Drag Coefficient in Slot Plug for Gas Stirring
Teshugang, 2007 The pressure difference between inlet and outlet of commercial size slot plug and velocity of gas at outlet have been measured in laboratory. It is obtained that the drag coefficient of plug is approximately equal to 44/Re, the flow condition is laminar ...
周建安, 朱苗勇, 潘时松
doaj
Shuitu Baochi Xuebao[目的] 针对双排高立式尼龙网阻沙障与草方格固沙障联合应用,开展风洞试验研究,以优化联合沙障中尼龙网阻沙障孔隙度配置及探究各孔隙度下联合沙障的防沙效益。[方法] 基于风洞模拟试验数据,开展不同孔隙度(40%,45%,55%)联合沙障,在不同风速下的风速流场、空气动力学粗糙度、摩阻风速、输沙率随高度和阻沙率方面的变化特征研究。[结果] (1)相同风速下尼龙网阻沙障孔隙度40%时,联合沙障弱风区面积最大;(2)随着尼龙网阻沙障孔隙度的增大,空气动力学粗糙度和摩阻风速减小,相同风速和相同位置时,40 ...
王茂林 +4 more
doaj
Shuitu Baochi Xuebao, 2017 为了研究不同种类和形态有机物料对原生盐碱地水稳性团聚体特征以及物理性质的影响，以吉林西部地区原生盐碱地为研究对象，通过大田试验，分析了颗粒玉米秸秆、正常玉米秸秆、牧草以及羊粪等有机物料对原生盐碱地的浸水容重、沉降系数、田间持水量和蒸发速率等物理指标的影响，及其对土壤水稳性大团聚体和微团聚体的数量、形态、平均质量直径(MWD)、破坏率(PAD)、水稳系数、平均质量比表面积和分形维数等指标的影响。结果表明：(1)各处理中水稳性团聚体组成以微团聚体占主要成分，其中以0.05～0.25 mm粒径为主 ...
何瑞成, 吴景贵, 李建明
doaj
Zhendong Ceshi yu Zhenduan针对抛光过程中存在的加工效率低、表面质量差等问题，基于柔性机构理论开发了一种高解耦性能的振动辅助抛光装置，并设计复合控制系统提高其跟踪精度。基于柔度矩阵法，建立了振动辅助抛光装置的理论模型，通过有限元分析法，对振动辅助抛光装置的性能进行分析。性能测试实验结果表明，振动辅助抛光装置的固有频率为1 593 Hz，x方向和y方向的耦合误差率为2.5%和2.8%。建立系统的迟滞模型，并通过最小二乘法对测试数据进行拟合，误差为2.98%。控制系统测试实验表明，与比例⁃积分⁃微分（proportion ...
doaj +1 more source
[Effect of modified hot-etching treatment on the mechanical properties of zirconia and zirconia/resin bond strength]. [PDF]
Beijing Da Xue Xue Bao Yi Xue BanYang X, Wu Y, Lv P.
europepmc +1 more source
[A rare case of Rosai-Dorfman disease involving the pituitary stalk and presenting initially with diabetes insipidus]. [PDF]
Zhong Nan Da Xue Xue Bao Yi Xue BanLi L, He H, Zhao S, Chu L, Jin P.
europepmc +1 more source
[Research on blood viscoelasticity detection based on electrowetting technology]. [PDF]
Sheng Wu Yi Xue Gong Cheng Xue Za ZhiWang C, Huo W, Yang L, Huang X, Yang W.
europepmc +1 more source
[Long-term prognosis and influencing factors of anterior composite resin restoration]. [PDF]
Hua Xi Kou Qiang Yi Xue Za ZhiChen W, Wu F, Wei X.
europepmc +1 more source
[A method for measuring the thickness of biological tissues based on piezoelectric effect and deep learning]. [PDF]
Sheng Wu Yi Xue Gong Cheng Xue Za ZhiHu J +8 more
europepmc +1 more source