共查询到18条相似文献,搜索用时 234 毫秒
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锂金属是具有高能量密度的负极材料,是下一代高能量密度电池研究的重点。在锂金属负极的改性研究中,锂对称电池是最常用的测试对象,但判断其短路的依据尚未统一,因此存在部分对短路数据的解析错误。本文利用原位电池对锂沉积过程中由于枝晶生长导致的短路现象进行了描述,对锂金属对称电池在充放电过程中的短路现象进行了分类和讨论。通过区分硬短路、软短路及电池活化过程,提出了判断锂对称电池中枝晶生长及电池短路的依据,为判定锂金属负极改性方法的有效性提供参考。 相似文献
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MB25镁合金中的准晶体与晶体相的研究 总被引:3,自引:0,他引:3
利用透射电子显微术(TEM)及能谱仪微区成分分析(EDS)技术,对含有稀土元素的铸态Mg-Zn-Zr-Y系高强镁合金MB25中的稀土相鉴定发现,在铸态合金的晶界上存在准晶相,其电子衍射谱显示出5-3-2次对称的特点,为二十面体准晶相。在与准晶相连区域发现一种MgZn_2型的Laves相,其点阵常数为a=0.542nm,C=0.873nm。 相似文献
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混合表面活性剂存在下二溴羟基苯基荧光酮光度法测定痕量铜 总被引:7,自引:0,他引:7
研究了在氯化十六烷基吡啶(CPC)和吐温-40存在下,铜与二溴羟基苯基荧光酮(DBH-PF)显色反应,结果表明,在pH6.0-7.1的六次甲基四胺-盐酸缓冲溶液中,铜与DBH-PF形成1:1配合物,其最大吸收峰全于570nm摩尔吸光系数1.2×10^5L.mol^-1.cm^-1,铜含量在0~6μg/25mL范围内符合比尔定律,方法用于测定环境水标样及牛肝粉标样中的痕量铜。 相似文献
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隔膜在锂离子电池中起着防止正负极直接短路和提供离子传输通道的作用,决定着电池的安全性能.在本文中,我们利用锂-铜电池的短路时间建立了一种评价隔膜安全性能的方法 .通过对电池短路时间的研究发现,对于同一种类型的隔膜,短路时间与隔膜厚度和内阻的线性相关度较高,隔膜厚度和内阻的增加均能延长电池的短路时间.同一厚度不同类型的隔膜,其电池的短路时间与隔膜自身的微孔结构相关.电池的短路时间与隔膜的穿刺强度之间的线性相关程度较低,结合电池短路后隔膜表面枝晶形貌的观察,我们推测枝晶是沿隔膜的孔道持续生长最终穿透隔膜,而非刺穿隔膜导致的电池短路.利用不同厚度的隔膜组装锂硫电池,发现循环寿命与隔膜厚度具有显著线性相关性,验证了测试方法在实际电池使用中的有效性.同时,研究也证实,利用功能隔膜调控锂的沉积行为、抑制锂的枝晶沉积能极大延长电池的短路时间,提升电池的安全性能,这为新型高安全性复合隔膜及电池的研究和设计提供了新的思路和理论依据. 相似文献
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阳极铜是铜电解过程的重要产品,其中含有一定量的金、银等贵金属,快速准确地测定阳极铜中的贵金属含量,具有重要的现实意义。采用火试金重量法可以同时且快速地测定出样品中的金量和银量,试样与适量的熔剂经高温熔融,铅将金、银富集起来形成铅扣,灰吹得到金、银合粒,用硝酸分金,重量法测得金量;用电感耦合等离子体发射光谱(ICP-OES)法测定分金液中的杂质量和金量,合粒质量减去金量及杂质量即为银量。此方法精密度好,准确度高。金、银的加标回收率在97.6%~102%,可以很好地满足阳极铜中金、银含量的测定。 相似文献
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利用火灾痕迹物证综合实验台,制备铝导线在不同过载电流作用下的残留物,用扫描电子显微镜观察、分析导线的断口形貌.结果表明:随着过载电流的增大,杯锥状断口逐渐变大,杯锥底部韧窝越来越大.因此,利用扫描电子显微镜观察、分析铝导线的断口形貌特征,可以鉴别其是否过载以及过载的程度. 相似文献
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《Mendeleev Communications》2021,31(4):459-461
The influence of contact barrier heights on the principal characteristics (open circuit voltage, short circuit current, fill factor, and power conversion efficiency) of a perovskite photovoltaic element was examined by numerical simulations in order to reach a maximum efficiency of the element. The role of crystal fields at the perovskite boundaries was pointed out. 相似文献
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Qiang Yuan Wei Jiang Lijia An R. K. Y. Li 《Journal of Polymer Science.Polymer Physics》2005,43(3):306-313
The effects of glass bead (GB) size and annealing temperature on the formation of β‐crystals of glass bead‐filled polypropylene (PP) are studied in this articles. Differential scanning calorimetry (DSC) measurements indicated that the amount of β‐form in PP crystals was a function of the glass bead content and size. For a fixed glass bead content, it was found that the smaller the diameter of the glass bead, the higher was the content of β‐crystals formed in the PP. On the other hand, wide‐angle X‐ray diffraction (WAXD) measurements revealed that the annealing temperature was also a major factor that affected the crystallization behavior of glass bead‐filled PP. It seemed that the blends with different glass bead contents had their own optimal annealing temperatures for β‐crystal formation. As an example, when the glass bead content was 48 wt %, the optimal annealing temperature for β‐crystal formation was about 108 °C, whereas it shifted to 100 °C for 14 wt % glass bead‐filled polypropylene. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 306–313, 2005 相似文献
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Qing Ji XIE Xiao Lian SUN Xiao Lan GU Hong Wei LIU You Yu ZHANG Shou Zhuo YAO 《中国化学快报》1999,10(1):73-76
Thequartzcrystalimpedancetechniqueisapowerfulmethodtocharacterizecrystalresonancesincemultipleinformationaboutcrystalresonanceincludingtheresonantfrequencyandchangesinsomephysicaland/orchemicalpropertiesofthetestsystemcanFigure1.Equivalentelectricalc... 相似文献
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Hierarchical nanomanufacturing: from shaped zeolite nanoparticles to high-performance separation membranes 总被引:1,自引:0,他引:1
Despite more than a decade of intense research on the high-resolution selectivity of thin zeolite films as alternatives to energy-intensive industrial separations, membranes consisting of intergrown, oriented zeolite crystals have fallen short of gaining wide commercial application. Factors including poor performance, high cost, and difficulties in scale up have contributed to this, and have also stunted their application in other niche markets. Until recently, rational design of these materials was limited because of the elusive mechanism of zeolite growth, and forced more empirical approaches. New understanding of zeolite growth along with recent advances in the molecular engineering of crystal microstructure and morphology, assembly of crystal monolayers, and synthesis of ordered films constitute a strong foundation for meeting stringent industrial demands in the future. Together with new processing capabilities, such a foundation should make it possible to synthesize commercially viable zeolite membranes through hierarchical approaches. Such advances open exciting prospects beyond the realm of separations for assembly of novel and complex functional materials including molecular sensors, mechanically stable dielectrics, and novel reaction-diffusion devices. 相似文献
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The losses in the cupellation and parting procedures of the fire assay for gold were evaluated with simulated buttons of lead foil. Variation in weight of lead, silver-gold ratio, and cupel size did not affect gold losses. Removal of cupel material from the bead increased the gold loss. Flattening the bead and increasing the parting acid strength reduced the gold losses somewhat. No evidence of losses by volatilization was observed. 相似文献
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报道了一种新型近红外响应光热转换试剂/液晶弹性体复合材料.目前绝大多数近红外吸收的无机金属纳米粒子,由于自身或其稳定剂(如长链硫醇或季铵盐)的化学性质,会致使经典的Finkelmann两步硅氢化加成反应中所使用的催化剂中毒失活,从而极大地限制了无机金属纳米粒子/液晶弹性体复合材料的拓展与应用.为了解决这一科学问题,我们采用了两步硫醇-烯点击化学快速制备单畴取向液晶弹性体薄膜的技术,将对近红外光有强吸收的油溶性硫化铜纳米粒子,成功地掺杂入聚硅氧烷液晶弹性体体系中,制备了近红外响应的硫化铜纳米粒子/液晶弹性体复合薄膜.通过使用紫外可见光谱、透射电子显微镜、扫描电子显微镜、偏光显微镜、示差扫描量热法、变温广角X射线散射对该复合材料进行了深入的研究,结果表明:该薄膜材料在980 nm近红外光源的照射下,可以实现高效的光热转换,从而实现快速、可逆的二维伸缩运动. 相似文献