汽车变速器CAE仿真与试验分析

变速器作为汽车动力总成系统的关键部件,其功能的可靠、耐久的长短等性能直接影响到汽车的整体功能。CAE仿真与试验是变速箱性能验证的重要手段,通过结合设计阶段的CAE仿真与样件阶段的试验验证进行对比研究,能够使变速器在量产前完善设计,减少试验的样本量,从而实现缩短变速器设计周期和降低成本的目的。     

制度质量、技术创新的挤出效应与资源诅咒—基于我国省际面板数据的实证分析

利用30个省际面板数据验证存在"资源诅咒"的同时,从制度质量和技术创新挤出效应的角度对其产生机理进行了基于门槛模型的实证检验,并对门槛变量的影响因素进行了实证分析。结果表明:1)自然资源和经济发展之间显著的存在基于制度质量和技术投入水平的单门槛效应,制度质量和技术投入水平的提高可以有效地改善资源依赖对经济增长的负面影响;2)资源依赖度是产生诅咒的关键,丰裕的资源虽然和经济增长表现出正相关的关系,但是其对制度质量和技术投入水平的影响是负相关的,资源开发对技术创新具有挤出效应。另外实证结果还显示出产业结构的调整可以在一定程度上缓解经济增长对自然资源的依赖性,但是缺乏稳定性。     

几种蒸散模型在玉米农田蒸散量计算中的应用比较

模拟蒸散的物理过程,计算农田蒸散量是进行生态系统水资源评价和管理的重要手段,同时也是气象部门进行土壤湿度预报的首要条件.本研究以玉米农田为研究对象,基于涡度相关法观测的蒸散实测资料,比较分析了基于常规气象数据的蒸散模型(Hargreaves法、Priestlev-Taylor法、FAO-Penman-Monteith法)和基于气象梯度数据的蒸散模型(波文比法、梯度法、生态系统过程模型模拟)的模拟精度.结果表明:①Hargreaves法、Priestley-Taylor法和FAO-Penman-Monteith法日蒸散的模拟结果较为一致,总体上高估20%～26%,其中Priestley-Taylor法模拟结果最优;②生态系统过程模型模拟的农田日蒸散精度较高,但模型中涉及的物理过程和参数较多,在实际应用中难于获取;③波文比法在波文比小于0.4且仪器精度较高时可以得到较准确的估算值.研究同时还指出,仪器的安装高度及高差设计对梯度法估算蒸散十分重要.     

山西省高校新聘专任教师队伍结构探析

近五年,山西省高校新聘专任教师队伍与以前相比,在性别比例、学历层次、学科比例等方面发生了一些新变化。本文以山西省高校教师岗前培训所获取的第一手统计数据为依据,着重对这些变化及其背后的动因进行阐述和探讨,并结合山西经济社会发展实际,提出了一些建设性的解决方案。     

高压输电线路雷击跳闸故障的判别

对输电线路不同的雷击事故进行分析,提出了雷击跳闸故障的判别方法。     

高校外语教学中本土文化渗透之我见

外语教学既是语言教学,也是文化教学,更是培养人文精神和国际意识的素质教育,其目的之一就是要使大学生利用外语进行跨文化交流。本文针对高校外语教学中存在的问题,提出了在外语教学中进行"本土文化"渗透的思路,力求在教学中加强中国本土文化元素的输入,从而使高校外语教学服务于中国文化建设。     

从社会调查看民国时期华北地区的人口状况

从李景汉和当时其他学者的调查入手,考察华北地区人口的性别比例和增长类型,从而引出对人地关系的探讨,并且以后者为重点。同时,从人地关系的分析中,还可以得知农民并非是一个愚昧、落后的群体,他们对农业生产、日常生活的安排都是有一定合理性的,在他们的生活中潜藏着一种朴素的智慧。     

Impacts of equity structure on audit fees: Evidence from Chinese A-share listed companies in Shanghai Stock Exchange

Based on the data of 923 Chinese listed companies in 2013 to 2014, we investigated the impact of company equity structure on audit fees from the perspective of cross section and period duration. It is found that there is a positive correlation between the proportion of state-owned shares in listed companies and audit fees. To be more specific, there is a U-shaped relation between audit fees and equity concentration which is represented by the proportion of the largest shareholder. And the equity restriction ratio, represented by the sum of the proportion of the second largest shareholder to the tenth, has a positive effect on audit fees.     

The Persuasive Influence of Nollywood Film in Cultural Transmission: Negotiating Nigerian Culture in a South African Environment

The popularity and viewership of Nollywood films have expanded across African and Western cities especially those with considerable Diaspora population. This study seeks to investigate whether watching Nollywood films is likely to lead to cross-cultural transmission of Nigeria’s cultural heritage to audience members in South Africa. Data for the study were collected using observation and surveys with Likert-type scales involving participants from a South African college. Results show that watching Nollywood films was significant in increasing participants’ knowledge and appreciation of Nigerian culture. Observed patterns indicate that a small portion of participants could mimic or reproduce some common Nigerian expressions and exclamations while a negligible percentage of participants could actually speak a smattering of Igbo, one of Nigeria’s three major languages.     

Effect of gear ratio on peak power and time to peak power in BMX cyclists

The aim of this study was to ascertain if gear ratio selection would have an effect on peak power and time to peak power production in elite Bicycle Motocross (BMX) cyclists. Eight male elite BMX riders volunteered for the study. Each rider performed three, 10-s maximal sprints on an Olympic standard indoor BMX track. The riders’ bicycles were fitted with a portable SRM power meter. Each rider performed the three sprints using gear ratios of 41/16, 43/16 and 45/16 tooth. The results from the 41/16 and 45/16 gear ratios were compared to the current standard 43/16 gear ratio. Statistically, significant differences were found between the gear ratios for peak power (F(2,14)?=?6.448; p?=?.010) and peak torque (F(2,14)?=?4.777; p?=?.026), but no significant difference was found for time to peak power (F(2,14)?=?0.200; p?=?.821). When comparing gear ratios, the results showed a 45/16 gear ratio elicited the highest peak power,1658?±?221?W, compared to 1436?±?129?W and 1380?±?56?W, for the 43/16 and 41/16 ratios, respectively. The time to peak power showed a 41/16 tooth gear ratio attained peak power in ?0.01?s and a 45/16 in 0.22?s compared to the 43/16. The findings of this study suggest that gear ratio choice has a significant effect on peak power production, though time to peak power output is not significantly affected. Therefore, selecting a higher gear ratio results in riders attaining higher power outputs without reducing their start time.