NUMERICAL SOLUTION FOR UNSTEADY 2－D FLOW USING THE TRANSFORMED SHALLOW WATER EQUATIONS

ＮＵＭＥＲＩＣＡＬＳＯＬＵＴＩＯＮＦＯＲＵＮＳＴＥＡＤＹ２－ＤＦＬＯＷＵＳＩＮＧＴＨＥＴＲＡＮＳＦＯＲＭＥＤＳＨＡＬＬＯＷＷＡＴＥＲＥＱＵＡＴＩＯＮＳ￥ＷｅｉＷｅｎ－ｌｉ（Ｘｉ＇ａｎＵｎｉｖｅｒｓｉｔｙｏｆＴｅｃｈｎｏｌｏｇｙ，Ｘｉ＇ａｎ７１００４８...     

溪落渡电站防渗料试验研究

本文对溪落渡电站比较方案——堆石坝心墙防渗料现场大型筛分，密度测定及室内物理力学性进行试验研究，并对东边坡三个区土料作为防渗料的优劣性提出评价。建议用料要求和进一步试验研究工作的改进意见。对该比较方案选用料场、用料技术要求等提供了依据。同时提出了防渗土料的试验研究方法和选料途径。     

水平附壁射流破异重流试验研究

本文提出了利用水平附壁射流破除异重流的新方法。通过水槽试验,对水平附壁射流破异重流的现象、拦沙及冲沙效果进行了详细研究,得出了不同水沙条件下附壁射流破异重流所需喷口流速表达式。     

RELATIONSHIP AMONG EVAPORATION FLUX OF GROUNDWATER, DEPTH OF WATER TABLE AND NEGATIVE PRESSURE HEAD IN BARE SOIL

1.　 INTRODUCTIONThe crisis of water resources is a global problem.Compared with other countries,Chi-na relatively falls shortof water resources.The amount of water resources per capita is justone fourth as the world average value. The distribution of water resources is outof balance.81 % ofthe water resources is concentrated in the reach of the Yangtse River and the south-ern areas of China,while only1 9% is in the areas of the north to the Yangtse River,inwhich the population is4 5.3%…     

非均匀颗粒群体沉速试验方法的分析

非均匀颗粒群体沉降现象在自然界相当普遍,本文分析非均匀颗粒群体沉速的试验方法,比较各种沉降试验和流态化试验,得到认识深度取样锥体筒流态化法是目前较好的试验方法。     

汾河二库碾压混凝土坝钻孔取芯和压水试验成果及分析

汾河二库碾压混凝土钻孔取芯累计进尺160.22m,钻孔直径为171mm,芯样直径为150mm,岩芯获得率为97.7％,钻取单根长度超过7m的芯样16根,其中最长为7.58m．从芯样观测可知,碾压混凝土整体质量好,岩芯表面光滑,结构密实,胶结情况良好．现场压水试验共钻进4孔,总进尺158．07m,共压水110段,在大坝迎水面及其它位置未发现出水点及压水段串通情况．从压水试验成果可知试验段均远小于要求的1Lu,最大值为0．0504Lu,,小于0．009Lu的数值占93．6％,说明碾压混凝土整体抗渗性能较好．     

《互换性与技术测量》课程实验教学的探索

实验教学作为高等学校实践教学的重要组成部分,是培养学生创新意识和实践能力的重要途径。文章针对传统《互换性与技术测量》课程实验的教学,突破传统的实验教学模式,大胆改革创新,同时引入比较性实验教学方法。这种方法为培养应用性和实用性人才,也可为满足市场人才的需要奠定良好的基础。     

Consumers’ valuation for food traceability in China: Does trust matter?

Food safety is a very important topic in China. We investigate Chinese consumers’ preferences and willingness to pay (WTP) for food traceability using a choice experiment. Given that consumers’ trust in the food system may affect their preferences and WTP, we also assess the interaction between consumers’ trust in government’s supervision of food safety and food labels and consumers’ preferences for traceable food products. Using data collected from a choice experiment on Fuji apples in a face-to-face survey in six Chinese cities, the results show that (i) consumers are willing to pay for traceable food but their valuations can differ upon the degree of their trust in government’s supervision of food safety and food labels; (ii) consumers are willing to pay for traceability with strong evidence of preference heterogeneity; (iii) government is not the most trusted safety inspection and certificate authority as found in prior studies using animal food products in China.     

石质急流滩水力特性概化试验研究

根据溪口型急流滩概化滩段的水槽试验,分析了急流滩段流速与水位的分布和沿程变化等水力特性,阐述了滩段水力特性与地形的关系,以及影响滩情的主要因素,讨论了计算滩段水面线中确定局部阻力系数的方法,     

堰塞坝漫顶溃决试验及相关数学模型研究

针对当前堰塞坝溃决试验粒径取值偏低和粒径相差不大的现状,采用两组粒径差别明显的砂样进行了堰塞坝垭口漫顶溃决试验。试验表明,同条件下粗、细两种颗粒坝体的溃决现象有着较明显的不同。垭口挡板提起后,细颗粒坝体以下切侵蚀为主,冲刷强度比较剧烈,坝体较容易发生溃决;而粗颗粒坝体则是以渗流出流形成的溯源冲刷为主,冲刷强度较低,溯源面逐渐向上发展,只有当其发展到垭口下端附近时坝体才有可能迅速发生溃决。试验还发现,下游坝坡对溃决过程的影响比较显著,坝坡越陡,坝体越易溃决,溃口的平均展宽速率也越大。此外以deVries输沙率公式为基础建立了具有物理意义的概念性溃口出流计算模型,并采用试验实测数据对该模型进行了验证,结果表明该模型具有良好的适用性。