输水渠道横断面设计水深测试及计算(综合性)实验     

陈祖森  马亮  李彦 《实验技术与管理》2007,24(2):152-153,156

输水渠道横断面设计水深测试及计算实验结合“灌溉排水工程学”及“水力学”等学科的知识,在实验过程中,通过对实验数据的测试、分析及计算和渠道模型实物的观摩,加深了对渠道设计原理的理解,与课堂上的理论教学起到了良好的互动作用。  相似文献   

Reliability of arterial spin labelling measurements of perfusion within the quadriceps during steady-state exercise     

Jonathan Fulford  Anni Vanhatalo 《European Journal of Sport Science》2016,16(1):80-87

Arterial spin labelling (ASL) provides a potential method to non-invasively determine muscle blood flow and examine the impact of interventions such as supplementation and training. However, it's a method with intrinsically low signal, leading to limitations in accuracy and temporal resolution. To examine these limitations, the current study measured perfusion via ASL on three occasions in the rectus femoris of 10 healthy adults, during light and moderate exercise, over three different exercise durations. For data sampled over 9 min, light intensity exercise gave an average perfusion of 35.0 ± 5.1 ml/min.100g^?1 with a coefficient of variation (COV) of 16% and single intraclass correlation coefficient (ICC) of 0.67. For the moderate bout, perfusion was 51.3 ± 5.6 ml/min.100g^?1 (COV 10%, ICC 0.82). When the same data were analyzed over 5 min 24 s, perfusion was 37.8 ± 11.13 (COV 30%, ICC 0.13) during light and 49.5 ± 8.8 ml/min.100g^?1 (COV 18%, ICC 0.52) during moderate exercise. When sampling was reduced to 1 min 48 s, perfusion was 41.2 ± 13.7 (COV 33%, ICC 0.26) during light and 49.5 ± 13.6 ml/min.100g^?1 (COV 28%, ICC 0.04) during moderate exercise. For 9 min a significant perfusion difference was found between the exercise intensities; however, this was not the case for sampling over 5 min 24 s or 1 min 48 s. Such findings illustrate the potential of ASL to non-invasively monitor muscle perfusion under steady-state conditions, but highlight that extended exercise protocols are necessary in order to generate date of sufficient reliability to be able to discriminate intervention dependent perfusion differences.  相似文献   

The effect of 14 weeks of vitamin D3 supplementation on antimicrobial peptides and proteins in athletes     

Cheng-Shiun He  William D. Fraser  Jonathan Tang  Kirsty Brown  Stephen Renwick  Jay Rudland-Thomas 《Journal of sports sciences》2016,34(1):67-74

Heavy training is associated with increased respiratory infection risk and antimicrobial proteins are important in defence against oral and respiratory tract infections. We examined the effect of 14 weeks of vitamin D₃ supplementation (5000 IU/day) on the resting plasma cathelicidin concentration and the salivary secretion rates of secretory immunoglobulin A (SIgA), cathelicidin, lactoferrin and lysozyme in athletes during a winter training period. Blood and saliva were obtained at the start of the study from 39 healthy men who were randomly allocated to vitamin D₃ supplement or placebo. Blood samples were also collected at the end of the study; saliva samples were collected after 7 and 14 weeks. Plasma total 25(OH)D concentration increased by 130% in the vitamin D₃ group and decreased by 43% in the placebo group (both P = 0.001). The percentage change of plasma cathelicidin concentration in the vitamin D₃ group was higher than in the placebo group (P = 0.025). Only in the vitamin D₃ group, the saliva SIgA and cathelicidin secretion rates increased over time (both P = 0.03). A daily 5000 IU vitamin D₃ supplement has a beneficial effect in up-regulating the expression of SIgA and cathelicidin in athletes during a winter training period, which could improve resistance to respiratory infections.  相似文献   

矿井轴流式主要通风机经济运行探讨     

余永来 《淮南职业技术学院学报》2002,2(3):73-75

轴流式通风机是煤矿常用的一种通风设备，用于矿井通风的轴流式风机，不仅功率大而且长时运转，因此，它是煤矿耗电量较大的机械设备之一。针对轴流式风机能量损失的一些原因作以分析，并提出使之可达到经济运行的若干技术措施。  相似文献   

高校现金流量表编制的依据与编制方法初探     

于洪祥 《天津职业院校联合学报》2007,9(6):127-130

随着我国高等教育事业的发展,高校财务活动已不再是简单的取得财政、事业收入,拨缴规定款项,和核算相关支出。作为会计主体,高校会计核算的内容正逐步走向多样化、复杂化。鉴于这种情况,应尽快在高校财务报表体系中增加现金流量表,全面反映一个学校一定会计期间现金流入、流出和净增加(减少)情况,以改变现行高校会计信息披露不完整,决策依据不充分的现状。  相似文献   

中国基础研究类高层次科技人才流动特征分析 ——以环境领域为例     

赵伟 《中国科技资源导刊 (中国信息导报)》2016,(4):81-86

探寻我国基础研究类科技人才,尤其是高层次科技人才的流动特征和规律,对于制定我国基础研究类科技 人才发现、培养和发展的政策具有重要意义。本文以环境领域国家杰出青年科学基金获得者为研究对象,对中国该领 域基础研究类高层次科技人才的机构流动和国别流动特征进行分析。基于马斯洛需求理论,进一步对不同动机产生的 人才流动所对应的年龄分布进行探讨,为我国基础研究类高层次科技人才的政策制定提供参考和借鉴。  相似文献   

自力式流量控制器在热网中的应用     

王秋玲  田德华 《河北能源职业技术学院学报》2003,3(4):70-72

开滦荆各庄热水采暖系统98年以前采用普通阀门调节流量，定量困难，由于在检修过程中频繁开关，导致调节功能失效，供暖用户冷热不均。自98年后逐步改用了自力式流量控制器进行流量控制，改后，在使用过程中解决了以往存在的各种问题，实现了节能节水的效果。  相似文献   

连续定态传热过程平均温差的统一推导     

琚行松  赵红丽 《唐山师范学院学报》2007,29(2):28-30

采用统一的方法对定态传热逆流和并流的平均温差进行了推导。推导过程无需假定冷热流体的特定流向,并利于得到对数平均温差“同侧相减”的规律。  相似文献   

人造金刚石提纯废水处理沉淀池的设计     

黄世谋  苑玉洁 《三门峡职业技术学院学报》2003,2(3):71-73

本文对人造金刚石提纯废水进行了研究,在试验和分析的基础上,根据生产实际设计出科学实用的竖流式沉淀池,可对悬浮固体的有用成分进行回收,能取得一定的经济效益。  相似文献   

Numerical investigation of cavitating flow behind the cone of a poppet valve in water hydraulic system   总被引：2，自引：0，他引：2  

高红  傅新  杨华勇  Tsukiji Tetsuhiro 《浙江大学学报(A卷英文版)》2002,3(4):395-400

Computational Fluid Dynamics (CFD) simulations of cavitating flow through water hydraulic poppet valves were performed using advanced RNGk-epsilon turbulence model. The flow was turbulent, incompressible and unsteady, for Reynolds numbers greater than 43000. The working fluid was water, and the structure of the valve was simplified as a two dimensional axisymmetric geometrical model. Flow field visualization was numerically achieved. The effects of inlet velocity, outlet pressure, opening size as well as poppet angle on cavitation intensity in the poppet valve were numerically investigated. Experimental flow visualization was conducted to capture cavitation images near the orifice in the poppet valve with 30° poppet angle using high speed video camera. The binary cavitating flow field distribution obtained from digital processing of the original cavitation image showed a good agreement with the numerical result. Project supported by the National Natural Science Foundation of China (No. 59835160) and Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry of China (No. 50175097)  相似文献