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71.
Seepage well is an emerging Low Impact Development (LID) technology that can effectively control the storm runoff. However, its rainwater infiltration rate and storage capacity still require further enhancement. By setting a horizontal infiltration structure at the bottom of conventional rainwater seepage well (CSW), an enhanced seepage well (ESW) was proposed in this study, and its infiltration performances compared with the permeable pavement (PP) and the CSW were systemically investigated using static infiltration experiment and HYDRUS-2D simulation. The results showed that the infiltration efficiency of ESW was significantly higher than that of PP and CSW, and the process of water infiltrated through soil mainly controlled the macroscopic infiltration rate. The Nash-Sutcliff Efficient (NSE) index was used to evaluate the accuracy and reliability of the HYDRUS-2D model, and the results of NSE values greater than 0.75 (varied between 0.75 and 0.91) confirmed the applicability of HYDRUS-2D to describe correctly the hydraulic behavior of the ESW system. Simulation infiltration tests showed that the ESW performed a higher average infiltration rate and fewer total runoff volume than the CSW, indicating the effectively enhancement of the infiltration and water retention capacity of ESW, especially under heavy rainfall intensities. Additionally, the ESW system exhibited an excellent runoff-control and rainwater retention capacity in an actual rainfall scenario. 相似文献
72.
73.
Discusses retouching of the Kallikak family photographs in H. H. Goddard's (1912) study of mental retardation and heredity, with reference to analyses by R. E. Fancher (see record 1987-31600-001) and S. J. Gould (1981), and concurs with Fancher that the retouching was probably not done for deceitful purposes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
74.
It appears that those federal agencies responsible for enforcement persist in the belief that a given test score can mean one thing in one subgroup and something else in another and/or that inferences from a set of test scores can be valid for one subgroup but not for another. First surfacing in early agency regulations in connection with the now discontinued "differential validity" requirement, the belief still manifests itself in the concepts of "unfairness" and "adverse impact." Furthermore, the determination of the presence or absence of adverse impact on the basis of the impact ratio involves numerous statistical and measurement issues. Use of the impact ratio to establish the prosecutorial posture of an enforcement agency is clearly flawed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
75.
N. Z. Mehdizadeh M. Lamontagne C. Moreau S. Chandra J. Mostaghimi 《Journal of Thermal Spray Technology》2005,14(3):354-361
Plasma-sprayed molten molybdenum particles (∼40 μm in diameter) were photographed impinging at high velocity (∼140 m/s) on
a glass substrate at room temperature. An optical sensor detected thermal radiation emitted by a droplet as it approached
the substrate and activated a time delay unit. After a selected time interval, an Nd:YAG laser was triggered, emitting a 5
ns pulse that provided illumination for a charge-coupled device (CCD) camera to photograph the impacting droplet through a
long-range microscope. By varying the delay before pulsing the laser, different stages of droplet deformation were recorded.
Impacting droplets spread into a thin circular film that ruptured and broke into small fragments. An optical detector recording
thermal radiation from the impacting droplet gave a signal that increased as the droplet spread out, reached a maximum when
the liquid film began to rupture, and decreased as portions of the droplet recoiled because of surface tension and then flew
out of view of the photodetector. 相似文献
76.
目前水槽实验一般采用压电式压力传感器测量泥石流冲击力,这种传统测量模式的电信号易受电线阻抗效应的影响,且没有考虑测量装置受冲击变形对测量结果所产生的影响。针对以上问题,基于光纤布拉格光栅(Fiber Bragg Grating,FBG)传感技术,设计了悬臂梁式泥石流冲击力测量系统; 基于泥石流的宾汉体模型和受冲击体的本构关系,构建了包含中心波长最大偏移量、结构材料弹性模量和流深的泥石流最大冲击力反演公式。依据测量系统的力-光耦合效应设计水槽实验,开展了7组不同密度(1.8、1.9、2.0 g·cm-3)的冲击实验工况。结果表明:①数据之间呈现较好的规律性,光纤布拉格光栅中心波长最大偏移量随着密度的增加而增大,同一密度下光纤布拉格光栅中心波长变化过程与泥石流冲击过程相吻合,从而验证了冲击力反演模型和测量系统之间具有良好的适应性; ②冲击力峰值为30.75~74.06 kPa,冲击力系数为0.92~1.95,与泥石流冲击特性相吻合,进而验证了本测量系统在克服传统压电式压力传感器自身缺陷的同时,亦能实现冲击力的稳定可靠测量。 相似文献
77.
利用citespace关键词共现分析方法,梳理了1980年以来人工智能对劳动就业影响的国内相关文献,发现目前的研究议题主要包括人工智能影响就业的机制、人工智能对就业规模的影响、人工智能对收入分配的影响、人工智能对就业形态的影响、人工智能对劳动过程与劳动关系的影响. 总体来看,目前的研究主要集中在与劳动力市场相关的议题; 理论性的论述占大多数,而具有说服力的实证研究较少; 宏观性的研究较多,深入企业与生产现场考察的微观研究较少. 未来应进一步拓展研究主题,进行多种视角与跨学科研究,重视实证研究与微观研究. 相似文献
78.
SHENDe-jiu WANGYu-lin GUWei-chao XING Guang-zhong Key Laboratory ofMetastable Materials Science Technology Yanshan University. Qinhuangdao Hebei P. R. China 《材料热处理学报》2004,25(5)
STEEL is the most widely used material in engineering,but unfortunately,steel exhibits poor wear resistanceand obvious contact corrosion.For decades,researchersprepared coatings on steel to improve its properties;ceramic is one of these coatings.To obtain ceramiccoatings on steel,many researchers use techniques suchas plasma spraying,laser cladding,etc.,but some ofthem are too expensive,some of them have a deep heataffected zone in the substrate,and some of them cannot bond well with the subs… 相似文献
79.
为了提高Fe-B-C合金的韧性,应用稀土-钛-氮复合变质剂改善Fe-B-C合金组织和性能。结果发现,Fe-B-C合金复合变质处理后的凝固组织明显细化,且组织分布均匀,并出现钛硼化合物,钛硼化合物不同于普通Fe-B-C合金中的Fe2B呈网状分布,而是呈断网状和块状分布,特别是经高温热处理后,硼化物变成球状和棒状,Fe-B-C合金韧性明显提高,由8~10 J/cm2提高至22~25 J/cm2。经变质处理的Fe-B-C合金可用于制造轧钢机导卫板,其耐磨性比高镍铬合金钢提高1.3倍。 相似文献
80.
结合±800 k V直流输电线路重冰区的实际工程数据,基于脱冰数值计算理论,通过数值方法模拟了六分裂导线在不同档数、档距、高差等复合因素影响下导线的脱冰动力响应过程,分析不同参数条件下导线和地线脱冰对悬垂绝缘子串和耐张绝缘串的冲击效应,得到最不利脱冰冲击效应的控制因素。研究表明:不同档距和高差组合下,档距和高差均最大时脱冰后的冲击效应最强;对于连续档,不同档脱冰时,对其相邻档导地线串的冲击效应最大;脱冰水平冲击效应主要受水平档距的影响,垂直冲击效应主要受高差的影响。 相似文献