期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
轿车发动机减振系统模型的建立和优化 被引量:6
1
作者 刘懿 靳晓雄 郝铮 《振动与冲击》 EI CSCD 北大核心 2001年第1期65-68,共4页
本文建立了 12个自由度的轿车发动机动力总成_副车架系统的仿真模型 ,并校验了模型的准确性。在此基础上进行了发动机减振系统的优化。并用MATLAB ,ADAMS ,ANSYS软件对系统响应进行了时域、频域 ,声场的优化比较 ,获得了良好的效果。
关键词 副车架 频域 仿真 优化 轿车 发动机 减振系统 模型优化 动力成振动
下载PDF
Effects of small-volume soccer and vibration training on body composition,aerobic fitness,and muscular PCr kinetics for inactive women aged 20-45
2
作者 Luke J.Connolly Suzanne Scott +11 位作者 Magni Mohr Giorgos Ermidis Ross Julian Jens Bangsbo Sarah R.Jackman Joanna L.Bowtell Rosemary C.Davies Susan J.Hopkins Richard Seymour Karen M.Knapp Peter Krustrup Jonathan Fulford 《Journal of Sport and Health Science》 SCIE 2014年第4期284-292,共9页
Purpose: The present study investigated the effects of 16 weeks of small-volume, small-sided soccer training soccer group (SG, n = 13) and oscillating whole-body vibration training vibration group (VG, n = 17) on... Purpose: The present study investigated the effects of 16 weeks of small-volume, small-sided soccer training soccer group (SG, n = 13) and oscillating whole-body vibration training vibration group (VG, n = 17) on body composition, aerobic fitness, and muscle PCr kinetics in healthy inactive premenopausal women in comparison with an inactive control group (CO, n = 14). Methods: Training for SG and VG consisted of twice-weekly 15-min sessions with average heart rates (HRs) of ~ 155 and 90 bpm respectively. Pre- and post-measurements of body composition (DXA), phosphocreatine (PCr) on- and off-kinetics, and HR measurements during stand- ardised submaximal exercise were performed. Results: After 16 weeks of training in SG, fat percentage was lowered (p = 0.03) by 1.7%±2.4% from 37.5% ± 6.9% to 35.8% ± 6.2% and the PCr decrease in the quadriceps during knee-extension ramp exercise was attenuated (4% ± 8%, p = 0.04), with no changes in VG or CO (time- group effect: p=0.03 and p = 0.03). Submaximal exercise HR was also reduced in SG after 16 weeks of training (6%± 5% of HRmax, p = 0.01). Conclusion: Short duration soccer training for 16 weeks appears to be sufficient to induce favourable changes in body composition and indicators of aerobic fitness and muscle oxidative capacity in untrained premenopausal women. 展开更多
关键词 Fat percentage Heart rate MRS PCr kinetics Small-sided soccer
下载PDF
Calculation model and mechanism analysis for rain-wind-induced vibration of stay cable 被引量:1
3
作者 谢桂华 刘荣桂 +1 位作者 蔡东升 陈蓓 《Journal of Central South University》 SCIE EI CAS 2014年第3期1107-1114,共8页
Rain-wind-induced vibration of cable was studied based on previous research achievements. According to the quasi-steady assumption, the governing equation of vertical motion of the cable was derived and the criterion ... Rain-wind-induced vibration of cable was studied based on previous research achievements. According to the quasi-steady assumption, the governing equation of vertical motion of the cable was derived and the criterion for unstable motion and occurrence mechanism was studied. A comparison was performed between the oscillation responses of the stay cable obtained from calculated model and previous results. The results indicate that the analysis model can reflect the main characteristics of wind-rain-induced vibrationt of the cable which is amplitude- and velocity-restricted, and it is probably related with the periodic vortex shedding of wake flow. It is essential for the occurrence of rain-wind-induced or wind-induced vibration of cable that the derivative of lift coefficient with respect to transient angle of attack is less than zero. When rain-wind-induced vibration occurs, the aerodynamic force has a dual function for the vibration, and the maximum amplitude of stayed-cable is determined by the relative value of aerodynamic exciting force and aerodynamic damping force. 展开更多
关键词 rain-wind-induced vibration stay cable governing equation STABILITY vortex shedding
下载PDF
Obstacles Facing the Implementation of Functional Magnetic Resonance Imaging (fMRI) of Brain in Jeddah City
4
作者 Abrar Mohammed Shafia M. Noor Hanan Mohammed Alzahrani Zuber Ahmed 《Computer Technology and Application》 2013年第2期123-126,共4页
fMRI (Functional Magnetic Resonance Imaging) is a relatively new technique that uses MRI (Magnetic Resonance Imaging) to measure the hemodynamic response (change in blood flow) related to neural activity in the ... fMRI (Functional Magnetic Resonance Imaging) is a relatively new technique that uses MRI (Magnetic Resonance Imaging) to measure the hemodynamic response (change in blood flow) related to neural activity in the brain. This paper aims to explore and identify the obstacles facing the implementation and applications of IMRI in radiology departments within Jeddah city by analyzing related data received by direct questionnaires and interviews with all the people working in MRI units in Jeddah city and finds that the major obstacle is lacking of awareness of fMRI among medical professionals and their training. 展开更多
关键词 fMRI (Functional Magnetic Resonance Imaging) brain imaging MRI (Magnetic Resonance Imaging).
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部