QQ客服 官方微博 反馈留言

浏览/检索结果: 共4条，第1-4条 帮助 已选(0)清除 条数/页：5101520253035404550556065707580859095100   排序方式：请选择作者升序作者降序题名升序题名降序发表日期升序发表日期降序提交时间升序提交时间降序 中国城市大肠癌高危人群对大肠腔镜筛查的接受度与支付意愿调查 期刊论文 中华预防医学杂志, 2015, 卷号: 49, 期号: 5, 页码: 381-386 作者:  石菊芳;  黄慧瑶;  郭兰伟;  任建松;  任英 收藏  |  浏览/下载：6/0  |  提交时间：2017/04/05 结直肠肿瘤  结肠镜检查  筛查  接受度  支付意愿   紫花苜蓿品种根部特性与持久性和生物量的关系 期刊论文 草业学报, 2014, 卷号: 23, 期号: 2, 页码: 147-153 作者:  彭岚清;  李欣勇;  齐晓;  岳彦红;  范树高 收藏  |  浏览/下载：2/0  |  提交时间：2016/08/17 紫花苜蓿  根茎  根系  地上生物量  持久性   35个10龄紫花苜蓿品种的持久性比较 期刊论文 草业学报, 2014, 卷号: 23, 期号: 1, 页码: 58-64 作者:  岳彦红;  齐晓;  王彦荣;  彭岚清;  余玲 收藏  |  浏览/下载：2/0  |  提交时间：2016/08/17 紫花苜蓿  持久性  草产量   Research on the close noise field of the piezoelectric pump (EI CONFERENCE) 会议论文 2006 IEEE International Conference on Mechatronics and Automation, ICMA 2006, June 25, 2006 - June 28, 2006, Luoyang, China Jizhuang L.; Jianhui Z.; Shouyin W.; Qixiao X.; Desheng L. 收藏  |  浏览/下载：42/0  |  提交时间：2013/03/25 Restraining the noise  meanwhile  improving the dynamic characteristics of the driving power of piezoelectric pump effectively are the final purposes of doing research on the reciprocating and flexural vibration of the piezoelectric vibrator. However  among many papers regarding piezoelectric pump  there are very few papers about the research on the noise of piezoelectric pump. This is far less than the research on the application of the piezoelectric pump in other fields. In this paper  the research on the flexural vibration deformation and vibration radiation noise of the piezoelectric vibrator are carried out. Firstly  the vibration equations of the piezoelectric vibrator are built and flexural vibration deformation function is deduced. Then  the simplified vibration model of the piezoelectric vibrator is introduced by using vibration theories of micro-area piston. Furthermore  theoretical calculation equations of sound pressure in close noise field and noise contribution equation of fluid in pump are deduced. Finally  a comparison is made between the theoretical calculation value and experimental value  and the contribution quantities of the piezoelectric vibrator and fluid in pump are obtained respectively under different frequencies. The consequence approves that the theory introduced by this research is true. 2006 IEEE.