wear-out period

Confined by the operation condition, intra-oral measurement can't make a precise result of tooth wear in a period. Conclusions: The 3-d computer assistant measure system can accomplish the analysis and measurement to the tooth wear, and further research in clinical application is required.

而口内测量由于操作的限制，很难实现对一定时期内牙磨耗量的精确测量。结论：该系统能进行牙磨耗图像的三维分析计算，其临床广泛的推广应用还有待于进一步研究。

After wheel re-pro filing, the wheel wear rate increases which will reduce the wheel turning period. The normal contact stress tends to be stable after wheel wear and is not obvious related to the wear volume around the nominal rolling circle.

车轮经过镟修后，磨耗速率会增加，镟修周期缩短，车轮经过磨耗后法向接触应力趋于稳定，车轮滚动圆磨耗量与法向接触应力无明显关系。

The Beijing Gardening and Greening Bureau encourages people to wear masks, sunglasses or shawls to protect themselves during the catkins period.

北京市园林绿化局建议人们在飞絮期间外出时佩戴口罩、墨镜、纱巾等防护用品。

The446 Canadian nurses in the study were assigned to wear either masks or N95 respirators while treating patients with respiratory illness and signs of fever over a roughly three-month period.

在大约三个月的里，此项的446名加拿大护士在护理患有呼吸系统疾病和发烧症状的病人时被指派佩戴外科口罩或者是N95呼吸防护口罩。

Original light fittings and door fixtures beguile with their period charm and obvious wear and tear.

原件灯具和门装置謆他们时期的魅力和明显的磨损.