共查询到17条相似文献，搜索用时 234 毫秒
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试验用压缩空气泡沫系统(CAFS)的设计 总被引：1，自引：0，他引：1
压缩空气泡沫系统（CAFS)是近年来出现并得到长足发展的一种高效泡沫灭火系统，介绍了试验用CAFS的设计和建立，包括CAFS系统动力配置的设计，总体参数的确定，泵和压缩机的选型及系统各部分的选型和设计。 相似文献
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该文介绍了一种压缩式空气泡沫灭火系统 ,该系统将压缩空气通入到有压混合液中 ,产生尺寸均匀 ,出口动量大的泡沫 .结果表明 ,泡沫的粘性、润湿性均显著提高 .试验采用了一种特殊设计的钟摆式测试装置 ,证明了泡沫屈服应力的存在 ,试验结果显示屈服应力随气体百分比和泡沫尺寸的提高而增大 相似文献
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股市泡沫问题向来是一个比较有争议的问题,本文以中国股市市盈率为基础,对中国股市的泡沫程度进行了简单判断,认为中国股票市场的泡沫程度的确较高,并分析了泡沫程度较高的原因,提出了改进措施。 相似文献
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泡沫炭(CF)是具有炭特征的海绵状炭材料.泡沫炭以其低密度、耐高温、高机械强度等优异性能而在较多领域展示出巨大应用潜力.对泡沫炭的制备原料、制备方法进行了综述,讨论了制备过程中的影响因素和其结构性能的差异,归纳了泡沫炭的结构、性质和应用,并对泡沫炭未来的发展进行了展望. 相似文献
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利用玉米秸秆酶解木质素通过添加和液化改性2种方法分别制备填充型和液化改性型聚氨酯泡沫。采用红外光谱(FTIR)对聚氨酯泡沫的结构进行表征,并通过压缩试验和动态机械(DMA)试验分别测定2种制备方法对聚氨酯泡沫的物理性能和动态力学性能的影响。结果表明:液化改性型聚氨酯泡沫密度低于填充型聚氨酯泡沫,凝胶量和压缩强度要高于填充型聚氨酯泡沫。当木质素液化产物添加量为30%时,液化改性型聚氨酯泡沫的压缩强度达到最大值291kPa。当多元醇替代物含量低于30%时,液化改性型聚氨酯泡沫的玻璃化温度稍高于填充型聚氨酯泡沫。 相似文献
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介绍了国内外利用林木剩余物与聚苯乙烯泡沫材料复合制造保温材料的研究与开发现状,并对林木剩余物的资源及加工工艺可行性进行探讨,旨在提出利用林木剩余物与聚苯乙烯泡沫材料复合制造保温隔音产品的新思路. 相似文献
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木材干燥窑的保温性与节能分析 总被引：5，自引：3，他引：2
常规砖砌壳体木材干燥窑热能消耗大，节能潜力很大，本文通过对窑体保温材料和大门密，保温性能改进措施的分析及应用，结果表明，壳体热损失减少６０％以上，总能源可减少１２％以上，节能效果显著，此外对用热油作为导热介质，也探讨了其节能的可行性。 相似文献
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压前含水率对杉木间伐材压缩木性能的影响 总被引：3，自引：0，他引：3
通过对杉木间伐材压缩密化的水分和物理力学性能进行分析,并观察木材微观结构的变化,可得出以下结果：1)压缩木各方向的水分分布不均匀,容易翘曲变形；2)水分对压缩木的物理力学性能有影响,压前含水率50％左右,压缩木硬度、抗弯弹性模量和抗弯强度最大,但冲击韧性随着压前含水率的增加呈下降趋势。从微观结构的观察可知,杉木间伐材压缩木的细胞只是被挤压,细胞腔变小而细胞壁未受到破坏。为了降低压后含水率,使水分分布均匀,可以采取两种办法：一是使初始含水率尽可能低,二是热压时间尽可能长。 相似文献
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Ren Li Zhiqiang Gao Shanghuan Feng Jianmin Chang Yanmei Wu Rongfeng Huang 《Journal of Wood Science》2018,64(6):751-757
Sandwich compression of wood that can control the density and position of compressed layer(s) in the compressed wood provides a promising pathway for full valorization of low-density plantation wood. This study aims at investigating the effects of preheating temperatures (60–210 °C) on sandwich compression of wood, with respect to density distribution, position and thickness of the compressed layer(s). Poplar (Populus tomentosa) lumbers with moisture content below 10.0% were first soaked in water for 2 h and stored in a sealed plastic bag for 18 h, the surface-wetted lumbers were preheated on hot plates at 60–210 °C and further compressed from 25 to 20 cm under 6.0 MPa at the same temperature on the radial direction. The compressed lumbers were characterized in terms of density distribution, position and thickness of compressed layer(s). It was found that depending on preheating temperatures, sandwich compressed wood with three structural modes, namely, surface compressed wood, internal compressed wood and central compressed wood can be formed. Density of the compressed layer(s) in wood increased gradually as a result of the elevated preheating temperatures. Higher preheating temperatures gave rise to bigger distance between compressed layer(s) and the surface, and preheating temperature elevation from 90 to 120 °C contributed to a maximal distance increase of 2.71 mm. In addition, higher preheating temperatures resulted in bigger thickness of compressed layer(s) over 60–150 °C and temperature elevation from 120 to 150 °C lead to the layers integration from two into one. Further temperature elevation over 150 °C reduced the thickness of the compressed layer in wood. SEM scanning suggested that cell wall bucking rather than cell wall crack occurred in compressed layer(s) and transition layer(s). 相似文献
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To improve the impregnation of wood, the pre-treatment by compression was systematically studied in terms of effects of compression ratio, compression direction, compression speed and compression-unloading place on the liquid impregnation in poplar and Chinese fir. The results showed: the impregnation increased 0.0065 or 0.0074 g/cm3 for every 1% increase of compression ratio when the compression ratio was lower or equal to 50 and 40% for poplar and Chinese fir, respectively; it continued to increase afterwards while the variation was quite big. There existed a significant difference of the impregnation of wood compressed at different directions in Chinese fir, but not in poplar. There existed a significant difference of the impregnation of wood compressed at different speed in both species. The impregnation of wood is likely to be in favor of radial compression in terms of the amount of impregnation. 5 and 10 mm/min were recommended as a compromise of impregnation and pre-treatment efficiency. The impregnation of wood that the compression unloaded in water was about 18.2 (poplar) and 9.2% (Chinese fir) higher in amount and was much quicker in speed than that the compression unloaded in air, and the difference between them was significant, suggesting that compression unloaded in water is significant to improve the impregnation. 相似文献
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基于美国材料实验协会ASTM D6866标准,利用超低本底液体闪烁技术,测定不同原料来源的泡沫材料中放射性碳同位素~(14)C含量,转化为生物基含量,从而用于鉴别生物基泡沫材料。实验中,分别利用元素分析和热重分析确定样品用量及其氧化燃烧温度,样品燃烧后产生的二氧化碳经过一系列化学反应合成为液体苯,通过测定合成苯中的放射性碳同位素~(14)C含量来区别鉴定生物质基泡沫材料和石油基泡沫材料,同时测定本底物质煤炭和标准物质糖碳中的~(14)C含量。结果表明:采用该方法测定的糖碳标准物质的~(14)C放射性活度值与标准值一致,由生物质基泡沫材料的~(14)C放射性活度值测定结果计算得到的生物基含量结果与美国Beta实验室采用加速器质谱(AMS)方法测试的结果一致。4种泡沫样品的生物基含量分别为18.77%、23.51%、5.39%和11.13%,全部为生物质基泡沫材料。说明利用该方法能够鉴别生物质基泡沫材料与石油基泡沫材料。 相似文献
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森林泡沫灭火枪是以轻型泵为动力,将森林泡沫剂与水混合后迅速变成泡沫。直接用于灭火的喷泡工具,主要由接口、接头、喷嘴、枪体等部分组成。野外灭火试验表明,该枪灭火效果较好。 相似文献