Microcalorimetric Study of the Action of Yb^3＋ ion on the Growth of Staphylococcus aureus

A microcalorimetric method was used to evaluate the action of Yb^3 ions onthe growth metabolism of Staphylococcus aureus.The power-time curves of the growth metabolism of Staphylo.coccus aureus and the action of Yb^3 ions were obtained by us-ing stopped-flow method at 37 ℃. For evaluation of the action,the growth rate constants ( k1 and k2) for the log phase 1, log phase 2, and the total heat effect (Qtotal) for Staphylococcus aureus were determined. The results show that Yb^3 ions at low concentrations have the stimnlatory effect on Staphylococcus au-reus and that Yb^3 ions at higher concentration could inhibit its growth.     

PROPERTIES AND MORPHOLOGY OF UNSATURATED POLYESTER/ACRYLATE-TERMINATED POLYURETHANE/ORGANOMONTMORILLONITE NANOCOMPOSITES

Unsaturated polyester resin （UPR）/acrylate-terminated polyurethane （ATPU）/organo-modified montmorillonite （OMMT） nanocomposites were prepared by the in situ intercalative polymerization method. Samples were prepared by the sequential mixing, i.e. mixture of the ATPU and styrene （S） and OMMT were prepared in the first step; UPR was then added to the pre-intercalates of ATPU/S/OMMT. Results indicate that the mechanical properties and thermal properties of UPR/ATPU/OMMT nanocomposites greatly depend on the amount of ATPU and OMMT. Results show that the addition of ATPU could increase the impact strength of UPR/ATPU composites, but the tensile strength, flexural strength and heat resistance of the materials are obviously decreased. When the weight ratio between UPR, ATPU and OMMT were 82：15：3, the impact strength and heat distortion-temperature of nanocomposite were greatly improved, meanwhile there was little change for other properties of the nanocomposites. The synergistic enhancement effects of ATPU and OMMT on the composites were observed. The structures and morphology of the composites were investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy.     

微量热法研究氰化物对鲤鱼肝线粒体代谢的影响

A microcalorimetric technique based on the metabolic heat-output was explored to evaluate the inhibition of cyanide on the mitochondrial metabolism of aquatic animal, Cyprinus carpio. The power-time curves could be divided into four parts： lag phase, active recovery phase, stationary phase, and decline phase, and the corresponding thermokinetic parameters were obtained. The maximum heat production rate Pmax decreased in a linear manner with the increase of concentration of cyanide, however, such mitochondria of aquatic animal were still metabolized actively even under the action of high concentration of cyanide. All the observations suggested that the mitochondria of this aquatic animal should exhibit considerable ability of cyanide-resistant respiration.     

半导体制冷技术原理与应用

半导体制冷（Semiconductor refrigeration）又称电子制冷、温差制冷或者热电制冷，是上世纪60年代后迅速发展起来的一项制冷技术。与普通制冷技术不同，半导体制冷不采用压缩机和制冷剂，不依赖制冷剂的相变传递热量，在直流电流通过具有热电转化效应的导体组成的回路时，利用热量转移特性制冷，是一种科技含量高的全新制冷技术。     

熔盐电磁感应加热器的实验研究及对比分析

通过搭建熔盐电磁感应加热试验系统,对电磁感应加热熔盐进行实验研究,得到不同工况下熔盐出口温度以及吸热量变化规律,并计算得到感应加热器对熔盐的加热效率。结果表明,熔盐的出口温度随线圈电流的增加而升高、随熔盐流速的增加而降低;熔盐流经感应加热器后的进出口温升随熔盐入口温度的升高而增大,但是温升的提高趋势并不明显;感应加热器对熔盐的加热效率随线圈电流、熔盐流速和熔盐进口温度的提高而增加;加热器材料为碳钢时熔盐的吸热量比不锈钢材料增加了23.39%,加热器材料为不锈钢和碳钢时对熔盐的加热效率最大值分别为71.44%和88.14%。     

飞行器热管理系统的热量流建模及优化

随着飞行器性能的提升,其高效热管理的重要性日益凸显,因而整体热管理系统逐渐得到广泛应用。本文以一种典型的飞行器整体热管理系统为研究对象,通过引入热阻、热动势和能量源等部件构建其热量流模型,应用基尔霍夫定律获得系统中能量的整体输运与转换规律,并明确系统性能和各设计、运行参数间的直接约束关系。以此为基础并结合遗传算法,以热管理系统的总体轻量化为目标,实现了其多参数全局优化。优化结果表明只依赖经验的系统设计容易错失最优解。     

基于热量流法的超临界CO2换热器性能分析

本文基于热量流法,应用进口温差定义的换热器通用热阻,采用分段法考虑超临界CO₂的物性变化,结合能量守恒方程,构建了超临界CO₂-冷却水换热过程的整体热量流拓扑模型,结合超临界CO₂物性库和经验关联式提出了换热器性能分析的流程图,实现了综合考虑物性-结构-运行参数的超临界CO₂-冷却水换热器的性能分析,进一步结合[火积]耗散热阻的概念提出了评价物性变化时换热器换热性能的等效热阻。通过分析获得了换热量的沿程分布规律,发现当进口压力为11 MPa时,总的换热量最大,此时等效热阻最小。总之,热量流法对超临界CO₂为工质的换热器设计和系统分析是可行和有效的。     

一种可视化DSC装置的设计与校准

设计研制了一种具有可视化功能的差示扫描量热装置,简称可视化DSC装置。该可视化DSC装置能够在差示扫描测量的同时,通过配套使用的显微镜摄像系统对测试样品的微观结构变化进行观察并记录。采用纯水为标准物质,对可视化DSC装置的温度测量与热量测量分别进行了校准,结果表明具有较高的测量稳定性。该可视化DSC装置能同时提供测试样品的热效应数据和微观结构的图像数据,提高了数据获取的同步性与测量结果的准确性。     

Gas flow in rotary kilns

This paper describes an experimental investigation on the flow characteristics within a rotating cylinder containing a rolling bed of sand. The axis of the cylinder was horizontal and there was no axial bulk flow of particles. The velocity field of the gas flowing through the cylinder was measured by hot-wire anemometry. The measurements indicate that the velocity field is asymmetric with respect to a diameter perpendicular to the granular bed. CFD calculations confirm this finding. The gas velocity profiles are crucial in determining heat transfer from gas to solid.     

平面近场辐射的单色效应和偏振态

本文计算了平面内涨落电磁场产生的电磁能密度和两平行平面间的微纳米尺度辐射热流密度,分析了近场辐射中单色效应对辐射的影响,结果表明对于碳化硅(SiC),单色效应极大地提高了电磁能密度和近场辐射换热量,而对于铝(Al)则没有明显的单色效应.本文还分析了不同偏振态对热辐射的影响.针对SiC材料,在微纳米尺度范围内,电磁能密度和辐射换热量主要受p偏振的近场倏逝波的影响,而s偏振电磁波和p偏振的远场传播波对微纳米尺度下辐射总量的贡献可以忽略.