排序方式: 共有144条查询结果,搜索用时 31 毫秒
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大体积混凝土的温控防裂一直是水利水电工程建设中的关键技术问题。在高温炎热地区,碾压混凝土重力坝施工期温控防裂要求高、难度大,温控措施较常温和高寒地区有明显区别。依托高温炎热地区的海南新春水库碾压重力坝工程,采用有限元仿真模拟施工期典型坝段温度场和应力场分布规律,分析和确定影响温控防裂效果的敏感因素,并参考其他类似工程,提出了相应的施工期温控标准和温控措施。研究结果表明,在推荐的温控防裂措施下,新春水库重力坝施工期温度场和应力场满足要求。研究成果已实际应用于该水库碾压重力坝工程,对类似工程温控防裂具有参考价值。 相似文献
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针对目前视觉测速方法存在检测精度低、鲁棒性差的问题,研究了一种结合模板匹配和混合高斯模型的测速方法。首先,利用混合高斯模型进行背景建模,提取出仅包含目标轮廓信息的前景区域图像。其次,使用参数优化的模板匹配法获取目标的高精度像素位移。最后,使用改进的二维测量模型法精确获取目标对应的像素尺寸。利用目标物理尺寸与图像中目标像素尺寸的比例关系来计算实际速度。实验结果显示,该方法对不同形状目标在不同速度下的测速结果的相对误差均在5%以内,准确度较高。 相似文献
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采用一种土壤过滤系统处理农村生活污水,分析了该工艺处理过程中CODCr、BOD5、NH3-N、全氮(TN)和全磷(TP)的时空变化规律。实验结果表明:去除季节效果由高到低依次为:夏季>秋季>春季>冬季。土壤过滤系统对CODCr、BOD5、NH3-N、TN和TP的最高去除率分别达到87.3%、88.2%、75.9%、59.3%和74.1%;在土壤过滤系统内,沿着水流的水平方向,各物质去除率逐渐增大。采用该技术处理后,排水中TN、TP的浓度较高,用于灌溉可减少化肥使用量和节省淡水资源。 相似文献
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La(III) Transport in Dispersion Supported Liquid Membrane Including PC-88A as the Carrier and HCl Solution as the Stripping Solution 总被引:1,自引:0,他引:1
The transport of La(III) through a dispersion supported liquid membrane with polyvinylidene fluoride membrane as the liquid membrane support and dispersion solution including HCl solution as the stripping solution and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC-88A) in kerosene as the membrane solution, was studied. As a result, the optimum transport conditions of La(III) were obtained as that concentration of HCl solution was 4.0 mol/L, concentration of PC-88A 0.16 mol/L, and volume ratio of membrane to stripping solution 30:30 in the dispersion phase, and pH value 4.0 in the feed phase. Ionic strength had no obvious effect on the transport of La(III). Under the optimum conditions, when initial concentration of La(III) was 0.8′10-4 mol/L, the transport rate was up to 96.3% during the transport time of 125 min. The kinetic equation was developed based on the law of mass diffusion and theory of interface chemistry. The diffusion coefficient of La(III) in the membrane and the thickness of diffusion layer between feed and membrane phases were obtained as 3.20′10-7 m2/s and 3.22′10-5 m, respectively. The calculated results were in good agreement with experimental results. 相似文献
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杨凌示范区水资源可持续发展研究 总被引:1,自引:0,他引:1
水资源是杨凌示范区发展的保障和制约因素.论述了杨凌示范区水资源的可持续发展现状和利用情况,分析了开发利用中存在的问题, 并提出相应的对策, 为今后合理开发利用和保护水资源提供参考. 相似文献
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