新型氧气-丙烷气割嘴     

江平  董敏 《闽江学院学报》2007,28(5):76-79

与乙炔相比,无论工作性能还是气源条件,丙烷都具有相当的优势.介绍了一种新型氧气-丙烷气割嘴,以改进传统的采用氧气-乙炔的气割方式,并采用F luent软件对氧气-丙烷的混合情况进行了数值模拟,结果显示割嘴出口速度场分布均匀,氧气-丙烷的混合情况对燃烧有利,证明此种割嘴形式具有较好的混气效果.  相似文献   

The influence of heterogeneous exposure and pre-deliberation queries on pretrial publicity effects     

Jon Bruschke  Andrew Gonis III  Sarah A. Hill  Pam Fiber-Ostrow  William Loges 《Communication monographs》2016,83(4):521-534

Prior research on pretrial publicity has produced mixed results and a roughly equal number of studies show an effect, show no effect, or show mixed results. We explored the effects of (a) homogenous vs. heterogeneous exposure (whether deliberating jurors were all exposed to the same publicity or not) and (b) pre-deliberation queries as potential contributors to mixed results. We found an effect for positive but not negative publicity on conviction rates but not evidence ratings. Exposure heterogeneity appears to explain these differences and pre-deliberation queries did appear to play some role in the obtained outcomes. Overall these findings do not replicate a robust publicity effect and future research should consider how homogeneous exposure and pre-deliberation opinion queries influence results.  相似文献   

焦耳定律的非独立性问题     

李大农 《黄冈师范学院学报》1994,(1)

本文指出有关焦耳定律非独立性的证明中仍存在的问题，并给出新的证明．  相似文献   

Neuromuscular and technical abilities related to age in water-polo players     

Fabio De Siati  Guillaume Laffaye  Giorgio Gatta  Antonio Dello Iacono  Johnny Padulo 《Journal of sports sciences》2016,34(15):1466-1472

Testing is one of the important tasks in any multi-step sport programme. In most ball games, coaches assess motor, physical and technical skills on a regular basis in early stages of talent identification in order to further athletes’ development. The purpose of the study was to investigate anthropometric variables and vertical jump heights as a free throw effectiveness predictor in water-polo players of different age groups. Two hundred and thirty-six young (10–18 years) male water-polo players partitioned into three age groups underwent anthropometric variables’ measures and squat- and countermovement-jump tests, and performed water-polo free throws. Anthropometric variables, vertical jump heights and throw speed – as a proxy for free throw effectiveness – resulted different over age groups. Particularly, throw speed changed from 9.28 to 13.70 m · s^?1 (+48%) from younger to older players. A multiple-regression model indicated that body height, squat-jump height and throw time together explain 52% of variance of throw speed. In conclusion, tall height, high lower limb power and throwing quickness appeared to be relevant determinants for effective free throws. Such indications can help coaches during talent identification and development processes, even by means of novel training strategies. Further research is needed over different maturity statuses.  相似文献   

A topography of free kicks in soccer     

Daniel Link  Otto Kolbinger  Hendrik Weber  Michael Stöckl 《Journal of sports sciences》2016,34(24):2312-2320

ABSTRACT

This study investigates the spatial relationship of performance variables for soccer free kicks. In order to suggest ways in which players might optimise their performance, we collected data from free kicks (<35 m to goal line) of two German Bundesliga seasons (2013/14, 2014/15) (n = 1624). In the analysis, we applied the ISO-map approach using colour gradients to visualise the mean values of a variable on a 2D-map of the pitch. Additionally, variograms were used to describe the degree of spatial dependence of the free kick variables. Results show that DENSITY, TYPE OF PLAY, PLAYERS IN WALL, DISTANCE TO WALL and RULE VIOLATION were strongly spatially dependent. Centrality and proximity to the goal increased the variables PLAYERS IN WALL, RULE VIOLATIONS and INTERRUPTION TIME, and the ratio of goals scored increased from 5.9% (central far) to 10.9% (central near). In 70.9% of the shots, players preferred a switched laterality, which did not result in a higher success rate. Furthermore, there was no statistical advantage for the defensive team when DISTANCE TO WALL was below 9.15 m or when there was a RULE VIOLATION. Crosses had a success rate (i.e., first controlled ball contact after the cross) of 20.8%. Played with natural laterality, they were 5% more successful than with switched laterality. Crosses from the right side outside the penalty box were 10% more successful than from the left side. Therefore, it might be worthwhile practising the defence of balls coming from this side.  相似文献   

八段锦竞赛功法对大学生机体自由基代谢和身体形态影响的研究     

李秋平  刘毅  彭婵  陈阳阳  任建立 《湖北体育科技》2016,(5)

目的:探索健身气功·八段锦(竞赛功法)对大学生机体自由基代谢和身体形态的影响。方法:主要采用实验法,随机抽取2014级康保系男生和女生各20人,持续进行4个月的功法习练,观察血脂和生理机能的变化。结果:大学生经过4个月的功法习练后,3个时间点测试SOD、CAT和大腿围指标呈上升趋势,MDA、XOD和腰臀比指标呈下降趋势,差异具有统计学意义;测试体重、体重指数和大臂围3项指标没有显著性差异。结论:健身气功·八段锦(竞赛功法)对大学生机体脏腑、固肾壮腰、提振精神、防治疲劳、改善血液循环、提高腰腹柔韧和腿部力量等方面有重要帮助。  相似文献   

n维低温强简并与完全简并理想费米气体的性质     

战丽波  王立志  柳盛典 《德州学院学报》2005,21(2):48-50

推导了能谱为ε=aps的n维理想气体的量子态密度,内能和压强的关系,并给出了n维完全简并、低温强简并理想费米气体的化学势、内能、简并压等热力学量的普遍表达式,通过分析比较得出T趋近于0时,低温强简并各热力学量过渡到完全简并的结论.  相似文献   

淮南矿区瓦斯发电可行性分析与实践   总被引：5，自引：0，他引：5  

高炯 《淮南职业技术学院学报》2005,5(1):61-62,68

瓦斯发电技术是瓦斯开发利用的一项新兴技术，该技术对煤矿的安全高效生产、环境保护、瓦斯能源有效利用有着重要的现实意义；就淮南矿区瓦斯发电项目，着重从淮南矿区瓦斯发电的可能性、安全性、经济效益、环境效益等进行了详细的阐述，以期为淮南矿区瓦斯发电事业提供一些有益的参考。  相似文献   

论市场经济条件下集体主义与个人的自由发展     

李振秋 《柳州师专学报》2004,19(1):72-74

在市场经济条件下，人的个性和自由得到了一定程度的张扬，怎样处理和理解好集体主义和个人主义的关系。如何在加强集体主义的同时兼顾个人的自由发展，本文就此问题作了一些探讨。  相似文献   

《庄子》二题     

曾祥旭 《南阳师范学院学报》2004,3(5):114-116

庄子的“吾丧我”涵盖工夫与本体两个层面,其含义是“唯丧我才能见道”,又是“见道后的自然解脱”。庄子“大木”的形象是丑的,但“大木”意象是美的,“大木”的本质是庄子对个体生死意义的独到领悟,又是一种超然而可求的人生态度。  相似文献