运动元记忆训练对元记忆水平和动作记忆的影响

通过2个月的运动元记忆训练,检验其对非体育专业学生元记忆水平和动作记忆成绩的影响.结果显示运动元记忆训练能显著提高大学生运动记忆策略和记忆监控水平;结果还表明训练能明显提高大学生的艺术体操和健美操动作记忆成绩(表现在动作数量上),而且艺术体操动作记忆的训练效应大于健美操.     

A Risk-Based Method for Modeling Traffic Fatalities

We describe a risk-based analytical framework for estimating traffic fatalities that combines the probability of a crash and the probability of fatality in the event of a crash. As an illustrative application, we use the methodology to explore the role of vehicle mix and vehicle prevalence on long-run fatality trends for a range of transportation growth scenarios that may be relevant to developing societies. We assume crash rates between different road users are proportional to their roadway use and estimate case fatality ratios (CFRs) for the different vehicle-vehicle and vehicle-pedestrian combinations. We find that in the absence of road safety interventions, the historical trend of initially rising and then falling fatalities observed in industrialized nations occurred only if motorization was through car ownership. In all other cases studied (scenarios dominated by scooter use, bus use, and mixed use), traffic fatalities rose monotonically. Fatalities per vehicle had a falling trend similar to that observed in historical data from industrialized nations. Regional adaptations of the model validated with local data can be used to evaluate the impacts of transportation planning and safety interventions, such as helmets, seat belts, and enforcement of traffic laws, on traffic fatalities.     

串联冰蓄冷系统设计中的泵能耗分析

介绍了串联冰蓄冷系统设计中泵能耗的3种节能方法：串联泵，变频泵和制冷机旁通，通过对某工程实例的模拟计算，对比分析了这3种方式的节能效果，提出了有效的节能方式。     

两相交流伺服电机动态性能的研究

对于两相交流电机的速度伺服系统,分析在幅值控制时系统的机械特性与调节特性,提出了影响两相交流伺服电机动态性能的因素是系统的机械时间常数及增益系数的变化。为了防止因机械时间常数及增益系数的变化而引起的动态特性变差,采用一种简易跟随模型参考自适应控制方法,通过模型与自适应机构的调节作用,改善两相交流伺服电机系统的动态特性和控制精度。计算机仿真结果表明,电机的动态持性良好。     

输送黏性介质时叶轮出口角对泵性能的影响

为了研究离心泵在输送黏性介质时,叶轮出口角对泵性能的影响,采用FLUENT软件,对2种不同叶轮出口角的 离心泵,分别在清水和5种不同黏性的油性介质下,进行数值模拟分析,预测离心泵在各工况下的水力性能。结果表明： 输送介质为清水时,增大出口角能提高扬程但会降低水力效率;介质运动黏度介于10. 80~ 65. 00 mm2／s时,增加叶轮出 口角能同时提高扬程和效率;介质运动黏度≥65. 00 1111112/S时,增加出口角不能改善其水力性能。文章研究结果能改善 离心泵的水力设计方法,确保泵的高效运行。     

双螺杆泵Ω形对称型螺杆流场数值分析

由于螺杆泵几何结构及流体流动状态较为复杂,其压力分布和速度等特性很难用数学解析法来分析计算。本文利用参数化设计模块建立双螺杆泵Q形对称型螺杆三维模型,构建双螺杆流道的流场分析模型,运用有限元分析方法得出了双螺杆泵流道内压力场和速度场分布规律。结果表明：流体在流道中的流速分布具有规律性,整个流道的流场速度高低交替变化,在螺杆与衬套间隙处的流动为层流,螺旋面接触区内的流动为复杂的湍流,离螺杆啮合区近的螺旋槽内易发生涡流。本研究结果对于了解双螺杆泵螺杆工况下的性能情况具有重要的参考价值。     

步进电机细分驱动系统设计

为了提高步进电机的运行精度,消除或减小振动现象,文章基于细分驱动技术,以单片机ATmega128为核心,应用恒流斩波PWM发生电路和H桥功率驱动电路设计了步进电机的驱动系统。系统控制参数通过上位机设定,以串口通信传给单片机。实验结果表明：电机运行平稳,振动噪音小,转矩大,精度高,系统具有良好的应用前景。     

Exposure to Traffic and Risk of Hospitalization Due to Injuries

Research on the risk of motor vehicle injuries and their relationship with the amount of travel has been only partially analyzed. The few individual exposure assessments are related to very specific subsets of the driving and traveling populations. This study analyzes the relationship between kilometers traveled and hospitalization due to motor vehicle injuries. Twelve thousand three hundred and sixty nine Spanish university graduates from the Seguimiento Universidad de Navarra multipurpose cohort study were evaluated. They had not been hospitalized due to motor vehicle injuries at baseline and were followed up to eight years. Biannual questionnaires allowed for self‐reporting of kilometers traveled in motor vehicles, together with incidence of hospitalization. Covariates in the Cox regression models included age and gender and baseline use of safety belt while driving, driving a vehicle with driver‐side airbag, driving a motorcycle, and drinking and driving. There were 49,766 participant‐years with an average yearly travel of 7,828 km per person‐year. Thirty‐six subjects reported a first hospitalization event during this time. The adjusted hazard ratio per additional kilometer traveled was 1.00005 (95% confidence interval 1.000013 to 1.000086). Even the smallest of reductions in the amount of kilometers traveled (from an average of 3,250 km per year to 1,000) has a statistically significant protective effect on the likelihood of sustaining hospitalization due to motor vehicle injury (aHR 0.9, 95% CI 0.78 to 0.98). In light of current policies aimed to reduce motorized traffic due to environmental concerns, it may be appropriate to consider the additional health benefit related to reductions in injuries.     

水泵叶轮设计中轴面流道及流线的确定

应用偏微分数值网络生成技术，提出了水泵叶轮设计的新方法，该方法可以准确地确定轴面流道和流线，较好地解决了水泵计算机辅助设计中的一个关键问题。     

深厚表土层冻结孔井斜控制技术

结合工程施工实践,针对冻结孔施工中的井斜控制技术进行了初步应用研究,优化后的井斜控制技术成功地用于工程施工。