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71.
Yuning Lou Yajuan Dong Xiaoyong Wang Feirong Gong Min Zhao Zongming Rong 《Journal of surfactants and detergents》2021,24(1):3-13
Two generations of novel linear-dendritic carboxylate surfactants C18-G1-(COONa)2 and C18-G2-(COONa)4 have been synthesized by the divergent method and their structures are characterized by 1H Nuclear Magnetic Resonance and Infrared analysis. The electrical conductivity measurement is used to measure the Krafft temperatures of C18-G1-(COONa)2 and C18-G2-(COONa)4, which are much smaller than those of the corresponding conventional surfactant sodium stearate. The markedly enhanced solubility of two linear-dendritic surfactants is ascribed to the high hydrophilicity of surfactant headgroups induced by the carboxylate and ester groups. The critical micelle concentration (CMC) values obtained from both the electrical conductivity and surface tension measurements indicate that the micellizations of linear-dendritic surfactants become favorable with the increase in the number of the surfactant headgroup. However, the surface activity parameters including the surface tension at the CMC, maximum surface excess, and minimum surface area reveal that C18-G1-(COONa)2 exhibits greater efficiency in absorbing at the air/water interface compared to C18-G2-(COONa)4, owing to their different steric repulsions of the surfactant headgroups. In addition, C18-G1-(COONa)2 and C18-G2-(COONa)4 have higher emulsifying ability than the conventional surfactants sodium stearate and sodium octadecyl sulfate. 相似文献
72.
针对大型软包锂离子电池热物性参数的测定问题,提出适用于该型电池的热参数表征方法. 基于准稳态导热原理,建立电池的传热理论模型. 开展实验研究电池的比定压热容和导热系数与温度的依变关系,分析热损对测试结果的影响,对测试方法的有效性进行验证. 结果表明,电池比定压热容随着温度的升高而线性增大,导热系数受温度的影响较小. 在900 s内可以测得电池热参数在10~60 °C下的变化状况,实验验证结果显示测算精度高于92.3%,具有测算周期短、准确度高和测试灵活等优势. 相似文献
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1 INTRODUCTIONWorldwide research and efforts are currentlyunderway to fabricate all solid state, rechargeableLi and Li ion batteries utilizing Li+ conductivepolymer electrolytes[1]. Solid polymer electrolytespossesses many advantages including high ionicconductivity, high specific surface energy, solventfree, wide electrochemical stability windows, lightand easy processability[2]. Apart from polyethy lene oxide ( PEO )[3], poly ( vinyl alcohol )(PAV)[4], … 相似文献
75.
高强度高导电的形变Cu-Fe原位复合材料 总被引:9,自引:1,他引:9
通过合金成分和变形工艺研究, 制备了一种高强度高导电性的形变Cu-Fe原位复合材料.实验结果表明, 铁含量越高, 强度越高, 导电性越低; 加入少量镁或锆, 可提高强度, 但同时损失导电性.在变形过程中, 加入适当的中间热处理, 在改变强度不太大的前提下, 能大大提高导电性.通过合理选择合金成分和变形工艺流程, 可制备不同强度和导电性等级要求的Cu-Fe原位复合材料. 相似文献
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78.
Electric and mechanical performances of Bi0.5Sb1.5Te3 prepared by spark plasma sintering 总被引:1,自引:0,他引:1
Thermoelectric (TE) materials are a kind of functional materials which can be used to convert directly heat energy to electricity or reversely.The thermoelectric effects hold great potential for application in power generation and refrigeration.Bi2Te3 and its alloys are well known as best TE materials currently available near room temperature.This paper studies respectively the effects of spark plasma sintering (SPS) on electric performance of Bi0.5Sb1.5Te3 thermoelectric materials that are prepared through vacuum melting and ball milling.Through X-ray Diffraction and cold field emission scanning electric microscope s4800, the phase constituent and microstructure of the TE materials samples were analyzed.Electric conductivity and power factor can be improved with the rise of Spark Plasma Sintering temperature (from 300 to 500 ℃) and pressure(from 30 to 60 MPa), and the density and mechanical strength of Bi0.5Sb1.5Te3 thermoelectric material increase, too. 相似文献
79.
稀土元素Ce对纯铜导电性及力学性能的影响 总被引:12,自引:0,他引:12
在纯铜中加入稀土元素Ce,研究不同含量Ce及不同保温时间对纯铜的导电性、抗拉强度、硬度、耐磨性等的影响.研究发现在纯铜中加入Ce起到净化、去杂质的作用,改善纯铜的导电性;也可使晶粒细化,改善纯铜的抗拉强度及其它力学性能.且熔炼时加入稀土后的保温时间要适当.在试验的条件下保温时间以30 min为宜,稀土Ce的最佳加入量w为0.02%. 相似文献
80.
The electrical conductivity of NiO was measured at 740°C in an oxygen pressure range of 10–2 –1.3 Torr. By means of continuous recording, longtime experiments were performed. The results show that for any admittance of oxygen, the electrical conductivity initially increased and then decreased to its initial value. For pressures higher than 0.1 Torr the decrease of the signal was reduced and the time required to attain the initial value sometimes reached several days. These results suggest that the electrical conductivity changes may be considered as a transitory phenomenon connected to attaining gassolid equilibrium. 相似文献