Calf massager: Intervention for body muscle discomfort during prolonged standing

Many occupations require workers to stand for long periods of time without proper interventions, which causes discomfort in the back and lower limbs. Therefore, this study aims to assess the effectiveness in alleviating body muscle discomfort during prolonged standing through the use of a calf massager. This study was conducted among male workers at a manufacturer with production line workers and the list was obtained from the HR Department and simple random sampling was done by number categorization. A total of 100 respondents (50 respondents for both the control and the experimental groups) participated in this study. The experiment took place in a room with a similar setup for the production line. Each respondent was requested to perform the simulated task for 2 hr. For the experimental group, the calf massager was turned on every 15 min. At every 15‐min interval after turning on the calf massager, respondents from both groups were required to evaluate their discomfort level on a Borg's scale CR‐10 questionnaire. The results showed that the level of body discomfort among respondents in the experimental group reduced (20–30%) compared with that of the control group. Multivariate analysis results revealed that the discomfort rating for the lower back, knees, thighs, calves, and feet was significantly lower (p < .05) among the experimental group compared with the control group. For lower body parts, the lower back region was statistically significant (p < .05) at the 90th, 105th, and 120th min; the thigh region was statistically significant (p < .05) at the 120th min; the knee region was statistically significant (p < .05) at the 105th and 120th min; the calf region was statistically significant (p < .05) at all minute intervals except the 15th and 45th min, while the feet region, was statistically significant at the 105th and 120th min. Therefore, this study indicates that calf massage treatment is capable of reducing body muscle discomfort during prolonged standing and highlights the significance of calf massage.     

深孔松动爆破提高瓦斯抽放率的应用研究

本文探讨了深孔松动爆破孔和瓦斯抽放孔的布置参数及工艺等 ,并设计了实施方案。在潘一矿的应用试验表明 ,用深孔松动爆破技术来提高低透气性煤层的瓦斯抽放效果 ,是一条很好的途径。     

ANALYSIS OF SEEPAGE FLOW IN A CONFINED AQUIFER WITH A STANDING COLUMN WELL

The standing column well for ground source heat pump systems is a promising technology with high efficiency and environmental benefit, where groundwater is drawn from the bottom of a well and then re-injected to its top after transferring heat with heat pumps. Heat transfer analysis of great significance and aquifer involves complex problems. Determining the groundwater seepage flow is a precondition to solve the energy equation describing the heat transfer of the system. Only when piezometric head is obtained, the seepage velocity can be determined according to Darcy’s law. In this article the groundwater seepage flow in an axial symmetrical geometry was studied under the assumption that gross groundwater flow is neglected. An analytical solution of the groundwater seepage flow for a confined aquifer was acquired by using the integral transform method, which may provide a foundation for heat transfer analysis of the standing column well system.     

Electrosynthesis of free‐standing poly(para‐phenylene) films in mixed electrolytes of boron trifluoride diethyl etherate and trifluoroacetic acid on stainless steel electrode

Free‐standing poly(para‐phenylene) (PPP) films have been electrosynthesized by direct oxidation of benzene on stainless steel electrode in mixed e1ectrolytes of boron trifluoride diethy1 etherate (BFEE) and trifluoroacetic acid (TFA). The oxidation potential of the monomer in these media is lower than those in the neutral media. Increasing the content of TFA in the mixed electrolyte can effective1y decrease the oxidation potential and increase the coup1ing rate of the monomer. The films obtained from these media were very shiny and flexible, and could easily be processed into various shapes by conventional mechanical methods. The films had a 1inear chain structure, and their degree of polymerization could be improved by increasing the TFA content in the mixed electrolyte. Moreover, the films had a fairly good thermal stability. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2462–2466, 2002     

一种小型高频段双极化喇叭天线的结构设计

文中设计了一种小型化高频段的双极化喇叭天线,详细介绍了具体的结构设计方法,充分考虑了加工装配环节对天线性能的影响,完成了理论设计和实物加工。通过暗室实测天线辐射单元的方向图、驻波比、增益等重要电性能指标,发现双极化均能较好满足X ～ Ku频段7 GHz的超宽带工作要求。对测试结果和电磁软件仿真结果进行对比,验证了结构设计对保证电性能的有效性,同时分析了性能差异项的具体原因,并提出了优化方案。该设计为类似小型化复杂天线的结构设计提供了参考。     

用亚稳态氩原子束制作纳米结构

纳米结构制作是纳米技术的重要组成部分,原子光刻技术是纳米图形制作的一项新方法.对直流高压放电产生的亚稳态氩原子束进行准直减小其发散角,亚稳态原子在与之传播方向垂直的激光驻波场中发生淬火并沉积在基底上,破坏吸附在基底表面的SAM膜(self_assembled monolayers),结合刻蚀技术可制作出纳米量级的图形.给出该技术制作纳米图形的基本原理、方案、相关理论及模拟结果.     

我国压铸业的国际地位与发展前景

根据我国压铸业现状及亚洲有关地区和世界各国的压铸概况，分析了我国压铸业的国际地位，并根据我国国民经济的发展，分析了我国压铸业有着广阔的前景。     

Comparative analysis of the workload in seated and standing horizontal submaximal lifting tasks

The objective of the present laboratory study was to analyse physiological responses of horizontal lifting tasks when they were performed in sitting and standing positions. Heart rate and blood pressure were used as indices of circulatory strain. Lifting tasks were performed under four lifting positions: sitting-forward lift, sitting-twist lift, standing-forward lift, and standing-twist lift. The weights of the loads were 3, 5 and 7 kg and the frequencies of handling were 1, 4 and 6 lifts/min. This study supports the idea that heart rate is a sensitive measure for evaluating the effects of seated horizontal lifting tasks. The lifting positions and workload (frequency × load × distance) are important parameters in the design of these types of tasks. It appears that within the experimental values examined in this study, a seated position could be recommended while performing horizontal lifting tasks at workloads ≤4·6 kg.m.min ^?1;. The results are supported by smaller physiological responses.