Objective The experimental study on the lift-up speed of a new kind of compliant aerodynamic foil thrust bearings was performed on the multifunctional test rig established for testing the performances of foil gas bear...Objective The experimental study on the lift-up speed of a new kind of compliant aerodynamic foil thrust bearings was performed on the multifunctional test rig established for testing the performances of foil gas bearings.Methods The lift-up speed of foil gas thrust bearing under given axial load was analyzed through the spectrum of axial displacement response in frequency domain.Results The test results indicated that the difference in the spectrum of axial displacement responses before and after lifting up of the rotor was obvious.After lifting up of the rotor,there were only larger components of rotation frequency and lower harmanic frequencies.If the rotor wasn't lift-up,there were also larger components of other frequencies in the spectrum.Conclusion So by analyzing the spectrum of axial displacement response,the results showed that the lift-up speed was about 1860rpm when the axial load was 31N.展开更多
Nowadays,one of the bottlenecks which hinder the development and application of carbon nanotube(CNT)nano device is that no pure semiconducting CNT(s-CNT)or metallic CNT(m-CNT)can be obtained,and for solving this probl...Nowadays,one of the bottlenecks which hinder the development and application of carbon nanotube(CNT)nano device is that no pure semiconducting CNT(s-CNT)or metallic CNT(m-CNT)can be obtained,and for solving this problem scientists proposed some methods on preparation or separation,but all the results still should be detected and feedback to the process for further improving the preparation and separation methods.Thus,it is very important to measure and distinguish the electrical properties of CNT.For that,scientists proposed a method to measure CNT electrical properties based on DC electrostatic force microscope(EFM)mode,which distinguishes m-CNT from s-CNT according to different scan line shape to CNT with different electrical properties.But,we discovered that the probe lift-up height will seriously affect the shape of the scan line,which makes this method not reliable in distinguishing m-CNT from s-CNT.In this paper,the authors deeply researched the influence of probe lift-up height and also gave corresponding theoretical analysis and explanation,which will greatly improve the method of detecting CNT electrical properties by EFM.展开更多
针对目前各大型储物仓库货物数量多、质量大和人工分拣、搬运较为困难导致的一些仓库管理效率低下等弊端,文章设计了一款基于STM32的自动分拣式仓储物流机器人。该机器人采用射频识别(Radio Frequency Identification,RFID)技术自动识...针对目前各大型储物仓库货物数量多、质量大和人工分拣、搬运较为困难导致的一些仓库管理效率低下等弊端,文章设计了一款基于STM32的自动分拣式仓储物流机器人。该机器人采用射频识别(Radio Frequency Identification,RFID)技术自动识别货物信息;通过算法设计自动规划路径运行到相应的货架位置;采用超声波避障技术避开障碍完成智能寻路;利用物联网传感器技术进行称重、利用机械化结构技术进行减震、利用STM32单片机技术上下台阶和升降。该机器人在以上几个模块的协同配合下,能将货物安全、快速、准确地存放于货架上。与传统的人工分拣相比,该机器人使管理效率得到了显著提高,大大降低了人工成本和危险系数,在实现仓储物流的无人化管理方面具有广阔的发展空间与应用前景。展开更多
基金This work was supported by the National Natural Science Foundation of China(No.50275116and50475088)the National High-Tech Research and Development Programof China(No.2002AA503020).
文摘Objective The experimental study on the lift-up speed of a new kind of compliant aerodynamic foil thrust bearings was performed on the multifunctional test rig established for testing the performances of foil gas bearings.Methods The lift-up speed of foil gas thrust bearing under given axial load was analyzed through the spectrum of axial displacement response in frequency domain.Results The test results indicated that the difference in the spectrum of axial displacement responses before and after lifting up of the rotor was obvious.After lifting up of the rotor,there were only larger components of rotation frequency and lower harmanic frequencies.If the rotor wasn't lift-up,there were also larger components of other frequencies in the spectrum.Conclusion So by analyzing the spectrum of axial displacement response,the results showed that the lift-up speed was about 1860rpm when the axial load was 31N.
基金supported by the National Natural Science Foundation of China (51005230, 61107043, 61375091, 51375477)the CAS FEA International Partnership Program for Creative Research Teams
文摘Nowadays,one of the bottlenecks which hinder the development and application of carbon nanotube(CNT)nano device is that no pure semiconducting CNT(s-CNT)or metallic CNT(m-CNT)can be obtained,and for solving this problem scientists proposed some methods on preparation or separation,but all the results still should be detected and feedback to the process for further improving the preparation and separation methods.Thus,it is very important to measure and distinguish the electrical properties of CNT.For that,scientists proposed a method to measure CNT electrical properties based on DC electrostatic force microscope(EFM)mode,which distinguishes m-CNT from s-CNT according to different scan line shape to CNT with different electrical properties.But,we discovered that the probe lift-up height will seriously affect the shape of the scan line,which makes this method not reliable in distinguishing m-CNT from s-CNT.In this paper,the authors deeply researched the influence of probe lift-up height and also gave corresponding theoretical analysis and explanation,which will greatly improve the method of detecting CNT electrical properties by EFM.
文摘针对目前各大型储物仓库货物数量多、质量大和人工分拣、搬运较为困难导致的一些仓库管理效率低下等弊端,文章设计了一款基于STM32的自动分拣式仓储物流机器人。该机器人采用射频识别(Radio Frequency Identification,RFID)技术自动识别货物信息;通过算法设计自动规划路径运行到相应的货架位置;采用超声波避障技术避开障碍完成智能寻路;利用物联网传感器技术进行称重、利用机械化结构技术进行减震、利用STM32单片机技术上下台阶和升降。该机器人在以上几个模块的协同配合下,能将货物安全、快速、准确地存放于货架上。与传统的人工分拣相比,该机器人使管理效率得到了显著提高,大大降低了人工成本和危险系数,在实现仓储物流的无人化管理方面具有广阔的发展空间与应用前景。
