Physiological and psychophysical responses in handling maximum acceptable weights under different footwear--floor friction conditions

A study on combined manual materials-handling tasks performed on floors under three friction levels was conducted. Eight male subjects participated in the study. The maximum acceptable weight of handling, including lifting, carrying for 3m, lowering, and walking 3m back at twice per minute was determined. The subject then performed the same tasks for 10 min. Heart rate, Vo2, energy efficiency, perceived sense of slip, and rating of perceived exertion for whole body strain were measured. The results showed that the effects of friction level on the maximum acceptable weights of handling, perceived sense of slip, Vo2, and energy efficiency were statistically significant (p相似文献   

SiC颗粒增强铝基复合材料的真空电子束焊接

针对SiCp/6061Al型复合材料进行了真空电子束焊接的初步探讨.试验结果表明:电子束电流越大,熔深越深;焊接速度越快,熔深越小;焊接过程中SiC颗粒会与液态铝发生界面反应,生成脆相Al4C3;镁元素的气化易导致焊缝气孔的生成.     

亚洲沙尘影响台湾期间大气悬浮微粒之粒径大小及化学组成变化趋势

旨在针对2002年3￣4月亚洲沙尘影响台湾期间,探讨位于台湾海峡中间澎湖群岛之大气悬浮微粒物化特征变化情形。本研究在澎湖群岛的小门村设置悬浮微粒采样站,借以采集近海面之大气悬浮微粒。由悬浮微粒浓度变化情情得知,2002年3￣4月共有3次亚洲沙尘暴抵达澎湖群岛,其粒径分布很明显地由双峰分布(bi-modaldistribution)转变为以粗微粒(coarseparticle)为主之单峰分布(singlemodaldistribution)。此外,悬浮微粒中水溶性离子成分之粒径分布亦随亚洲沙尘之抵达而呈明显变化,其中Cl-和Na+之变化趋势具有一致性,显示海盐之影响颇为重要;NH4+、Ca2+和SO42-均由细微粒(fineparticle)转变为粗微粒,显示(NH4)2SO4或CaSO4应为亚洲沙尘之特征指纹;NO3-主要来自当地污染(localemission),故其分布并无明显变化;Mg2+虽维持以粗微粒为主之单峰分布,但其浓度却增加约2倍左右。上述研究结果显示,当亚洲沙尘抵达台湾地区,不仅悬浮微粒之粒径大小改变,就连化学组成亦出现明显变化。     

气流速度对感烟火灾探测器响应灵敏度的影响

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小型CPL用高性能烧结毛细芯的研制

采用粉浆浇注工艺和氢气还原烧结工艺研制小型CPL用烧结镍毛细芯，通过优选粉浆液固比、添加剂的种类与数量、浆料pH值等参数制备了符合设计要求的烧结毛细芯。测试了毛细芯孔径、孔隙分布特征、孔径分布、孔隙度、渗透率等性能参数，分析了烧结气氛、温度、时间对毛细芯性能的影响。试验结果表明，研制的毛细芯孔隙度在68％以上，孔隙尺寸约4μm，渗透系数在10^-12～10^-13m^2之间。     

蒸汽爆炸粗混合阶段冷液中高温球传热阻力耦合特性的实验研究

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Application of megasonic cleaner to sub-micron particles of SIL optical flying head

 As the demand for large capacity storage drives has increased, the flying height of near-field recording (NFR) sliders becomes as small as 100 nm for super high storage density. Accordingly contamination problems have been a concern of information storage industry because it may cause a serious damage to solid immersion lens (SIL) of optical flying head. Sub-micro contaminants in air bearing of the NFR slider may affect the flyability and stability of the optical slider. In addition, the cleaning of small particles becomes more difficult as the contaminant particle size decreases because the adhesion force increases very much as the particle size decreases. Recently developed high-frequency ultrasonic (megasonic) cleaning technique have made it possible to remove sub-micron particles less than 100 nm without surface erosion and many remarkable results have been reported. In this paper, the megasonic technique is applied and tested for the cleaning of the flying head of NFR drive. 1 MHz ultrasound with maximum 100 W was used to remove polystyrene latex (PSL) particles and alumina particles deposited on the surface of the slider. Effective cleaning performance was observed without any damages on the slider surface using optical microscope and AFM at different ultrasonic energy levels and cleaning times. Received: 20 June 2002 / Accepted: 9 September 2002     

移动床过滤除尘的直接数值模拟研究及实验对比

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脉冲激光液相法制备纳米硅颗粒

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A fast integral approach for drag force calculation due to oscillatory slip stokes flows

In this paper, we describe an efficient numerical method for modelling oscillatory incompressible slip Stokes flows in three dimensions. The efficiency is achieved by employing an integral approach combined with an accelerated boundary‐element‐method (BEM) solver. First the integral representations for slip flows with two different slip models are formulated. The resulting integral equations are then solved using the BEM combined with the precorrected‐FFT accelerated technique. 3D numerical codes have been developed based on the method described above. These codes are then used to calculate the drag forces on oscillating objects immersed in an unbounded slip flow. Three objects are considered, namely a sphere, a pair of plates and a comb structure. The simulated drag forces on these objects obtained from the two slip models are compared. In the sphere case, the simulated results are also compared with the analytical solutions for both the steady‐state case and the no‐slip oscillatory case and are found to be in good agreement. In addition, qualitative comparison of the simulation results with the experimental results in the plate problem is also presented in this paper. Copyright © 2004 John Wiley & Sons, Ltd.