防治煤矿火灾的凝胶泡沫材料制备及其性能研究*

为解决纯水玻璃（WG）凝胶泡沫强度低、泡沫稳定性差易破碎,凝胶固水性差等问题。将保水剂和成膜剂引入WG凝胶泡沫中,对水玻璃凝胶泡沫进行优化设计,最终制备出保水性高、泡沫稳定性高、成膜性好的WG凝胶泡沫。研究结果表明:WG凝胶泡沫材料的最佳复配体系是发泡剂为十二烷基醇醚硫酸酯钠（AES）和十二烷基硫酸钠(SDS)按1∶2比例复配,浓度为0.8%,胶凝剂WG浓度为8%,交联剂NaHCO3浓度为2%,聚丙烯酰胺浓度为0.4%,成膜剂A浓度为1%,保水剂B浓度为0.3%;改性后WG凝胶泡沫具有更加紧密的网状结构,稳定性好,并且具有较好的成膜性,常温下半衰期达40 d;阻化实验表明,100 ℃此凝胶泡沫阻化率高达78.35%,能有效减缓煤的氧化放热速率抑制自燃;煤堆燃烧实验表明,改性后WG凝胶泡沫能有效抑制煤的燃烧,防止煤复燃。     

国外热塑性树脂基复合材料低轨原子氧环境效应研究进展

针对具有良好应用前景的热塑性树脂基复合材料,调研并分析了国外飞行试验获得的数据,从原子氧反应率、力学性能退化、微裂纹等多个方面分析研究了原子氧环境对热塑性树脂基复合材料作用效应,为空间站等低轨道航天器结构材料的设计和选择提供依据。     

驾驶人疲劳监测预警技术研究与应用综述

基于各种物理传感器的疲劳驾驶监测预警技术(DFMP),是交通安全领域的研究重点。这类技术主要包括基于驾驶人生理特征、车辆运行状态以及驾驶人行为特征的疲劳监测。分析论述各种疲劳监测技术的研究现状与进展、优缺点以及应用状况,介绍目前世界上常用的疲劳监测系统。通过分析比较得出:车道偏离监测、车辆运动参数监测、基于人眼、头部运动以及面部状态的疲劳监测等是目前的热点研究方向;系统软硬件的提升、基于机器视觉的多传感器多参数信息融合等是疲劳监测技术重要的发展趋势;更强的实时性、准确性和鲁棒性是疲劳监测技术的发展目标。     

Arm and Leg Girths of Industrial Workers During a Workday

The aim of this study was to characterize changes in the limb perimeters of workers in various widespread occupations in Estonian industry. Investigations were carried out using special measuring instruments designed at Tallinn Technical University. The subjects under investigation consisted of 202 workers: garment workers, tailoring cutters, shoe factory operators, weavers, press operators, fitters, and drivers.

Investigations in the workshops showed that during the initial part of a work-shift perimeters often decreased. By the end of the shift, girths increased markedly (up to 1.6%), depending on the properties of the external load. There are many reasons for this change, with fatigue often playing an important role.

The exact measurement of the girths of human limbs is of great importance for collecting information in the field of ergonomics. It is possible to find effective preventive measures against fatigue and occupational diseases.     

Visual Strain and Lighting Preferences of VDT Users Under Different Lighting Systems

Lighting influences users’ visual strain and well-being. Therefore creating lighting that ensures visual work conditions do not result in visual fatigue is a preventive activity. The aim of the study was to model different lighting systems for visual display terminal (VDT) work and to determine their influence on users’ visual strain and preferences. The results of the study showed that visual fatigue was lowest for indirect and compound lighting systems. On the other hand, in general, direct lighting realized by “dark-light” luminaires was the most preferred lighting system. Some interesting differences related to age, gender, and VDT work experience were found. On the basis of the obtained results lighting designers can be provided with some guidance.     

Electromyographic analysis of relevant muscle groups during completion of computer tasks using different computer mouse positions

Background. We analyzed muscular activity for different computer mouse positions during the completion of a timed computer task and determined whether the different mouse positions could affect muscular activity, productivity and perceived fatigue. Methods. The subjects were nine healthy young men. Two mouse positions were studied: the distal position (DP), with the forearm rested on the desk; the proximal position (PP), with only the wrist rested on the desk. The subjects performed a 16-min task in each position. Surface electromyography data were recorded for the upper back and shoulder muscles. Work productivity and muscular activity were measured for each mouse position. A visual analog scale was used to assess subjective fatigue. Results. Muscular activity was higher in muscle (m.) deltoideus (posterior) for the DP, while it was significantly higher in m. inferior infraspinatus for the PP. The visual analog scale score was significantly higher and work productivity was lower in the PP. Conclusions. We found that using a mouse in the DP rather than the PP leads to less activity of the external rotators, less perceived fatigue and more productivity. This suggests that the DP is preferable to the PP for computer work involving a mouse.     

型式试验过程中机械振动试验方法的研究

本文以正弦振动为例,结合相应的国标指导,介绍了电工电子和(或)核仪器类产品进行型式试验过程中机械振动试验方法的研究,以考察产品能否经受住预定的振动条件,并根据经受试验不同严酷等级的能力来划分设备等级。     

小产权房问题研究

对当前我国存在的小产权房所涉及的法律问题进行了研究分析,从小产权的概念、产生的原因入手,主要论述了小产权房产生的现实原因及深层次的制度原因。小产权房产生的现实原因主要有：高房价的促使、政府监管的不到位、保障性住房的缺位。深层次的制度原因主要是我国农村集体土地使用权流转机制的缺失。因此,政府应通过调控抑制高房价,加强政府部门的监管力度,完善我国的保障性住房建设,以及在制度层面上对我国农村集体建设用地使用权流转制度进行变革。     

喀斯特小流域不同土地利用方式对土壤物理性状和微生物的影响——以广西都安澄江小流域为例

以广西都安澄江喀斯特小流域为研究单元,分析了不同土地利用方式对土壤表层物理性质和微生物的影响。结果表明:随着自然林地向灌丛地、灌草丛地、草地、人工林地、退耕地和旱地的转变,土壤容重、pH呈增加趋势,而土壤含水量、总孔隙度、电导率逐渐降低。各土地利用方式中,细菌数量最多,均占85%以上,放线菌和真菌相对较少。从总量上看,灌草丛地和草地土壤微生物总量最大,自然林地、灌丛地和旱地次之,退耕地和人工林地最小。各土地利用类型中自然林地和人工林地的土壤微生物多样性指数较高,灌草丛地、草地、灌丛地和退耕地次之,旱地最低。     

废弃FR4环氧树脂覆铜板热解特性及固体残余物组成

采用TG(热重分析仪)和自制小尺度管式炉热解试验台架装置分别探讨了电子废弃物FR4环氧树脂玻璃纤维覆铜板在纯N2气氛中,以10 K/min升温速率加热到800℃的热解特性及在不同热解终温、停留时间下的固体残余物质量分布规律;采用SEM(扫描电子显微镜)分别对2种热解终温(450℃、550℃)下热解后玻璃纤维布进行微观形貌表征。TG热解结果表明,试样在N2气氛下热分解反应主要集中在第1阶段(300~400℃),失重量占总失重量65.55%,500℃后热解残余率趋于不变;管式炉热解结果及残余物表观微观形貌表明,热解温度和停留时间对玻璃纤维析出产率影响较大,而对铜析出产率几乎没有影响。当热解温度为550℃且停留时间保持10min时,废弃FR4环氧树脂玻璃纤维覆铜板可充分热解,玻璃纤维层间的环氧树脂系胶结剂已分解完毕,热解残余率达到最低值且玻璃纤维布自身未见明显变化。研究表明,通过热解焚烧技术电子废弃物资源具有规模化再利用的可能性。