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201.
试验研究是将锰酸锂烧结前的混合料(主要是二氧化锰与碳酸锂的混合物)压成团块,再放到烧结炉中进行烧结,由于经压团的物料接触很紧密,其堆密度由1.06 g/cm3提高到1.39 g/cm3,提高了31%,同样体积的匣钵可多装31%的物料,即在几乎相同的电耗及工时的情况下,锰酸锂的产量可提高31%,同时,也大大改善了物料间的高温固相反应动力学条件,有利于反应产物晶粒的长大及晶形完善,使锰酸锂产品的质量得到改善,压实密度由2.90 g/cm3左右提高到3.00 g/cm3以上,这有利于提高电池的体积能量密度。 相似文献
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以多种岩石循环加卸载声发射试验为基础,针对岩石损耗比和加卸载响应比特性进行了研究,探索岩石在受载过程中的内部损伤演化和破坏前兆特性。结果表明,在循环加卸载下角岩等三种岩石损耗比变化特性一致:低应力水平阶段损耗比较大,呈明显下降趋势;中等应力水平阶段比值下降趋势较平缓;高等应力水平阶段比值趋于稳定,在0.08~0.10时,试样破坏。而钨钼矿等三种岩石加卸载响应比变化特性一致:低应力水平阶段卸载时几乎没有声发射,加卸载响应比较大;中等应力水平阶段卸载时声发射较活跃,比值下降至1左右;高等应力水平阶段卸载时声发射很活跃,当比值重新大于1时,试样破坏。试验结果都体现了岩石内部损伤从很小到稳定扩展再到不稳定扩展的过程。可见,损耗比和加卸载响应比的变化特性均可用于评价岩石损伤情况,也可用作岩石破坏预测的参考依据。 相似文献
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Syntheses of LiCoO2 for cathode materials of secondary batteries from reflux reactions at 130–200 °C
《Journal of power sources》2002,104(1):125-131
Low temperature syntheses of LiCoO2 cathode materials for Li-secondary battery applications were studied in aqueous solutions by hydrothermal and reflux reactions. By controlling the oxidation potential of the reaction environments, we could synthesize phase pure LiCoO2 directly from Co(OH)2 at as low as 130 °C, contrary to the reported hydrothermal reactions at 200–220 °C starting with CoOOH. Having high pH over 15 and an O2 flow induced the oxidation reaction of the divalent cobalt in Co(OH)2. The products so obtained have well-crystallized high temperature form of LiCoO2 with the layered structure as proved by powder X-ray diffraction (XRD) and the Raman spectroscopy data. The particles have a uniform size distribution around 100 nm with well-developed crystallite morphology. 相似文献
208.
《Journal of power sources》2002,112(1):191-198
Asymmetric alkyl carbonate solvents (ACS) have been used as components of liquid electrolyte systems designed for Li-ion cells. Four ACS were selected: methyl-propyl carbonate (MPC), ethyl-propyl carbonate (EPC), methyl-isopropyl carbonate (MiPC) and ethyl-isopropyl carbonate (EiPC). The common features of all these ACS are a low melting point and a low viscosity, enhancing electrolytes conductivity toward low temperatures. The viscosity and the conductivity (salt: LiPF6, 1 M) of the ACS and their mixtures with ethylene carbonate (EC, 50% v/v), were studied as a function of the temperature (T). Arrhenius types plots of the logarithm of the conductivity versus 1/T reveals that ACS and ACS/EC mixtures are vitreous at low temperatures. The electrochemical and cycling behaviors of a graphite anode and a LiCoO2 cathode have been evaluated using coin cells with a Li counter electrode. The charge and discharge capacities have been determined as a function of the cycle number. MiPC which builds an highly stable surface film on the graphite electrode, can be used as a single-solvent electrolyte with only a slight decrease in capacity of the LiCoO2 cathode. All ACS/EC mixtures exhibit good filming properties at the negative electrode and no capacity loose at the positive electrode. The ability of some of the electrodes–electrolyte systems to undergo increased rates of discharge (C/5 to C/2) has been also evaluated. 相似文献
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《Pattern recognition letters》1988,8(3):171-179
A number of tesselation based GIS using quadtrees as the underlying data structure have been constructed in recent years. At present there is an almost universal trend towards the representation of a thematic layer as a collection of binary, linear quadtrees, one for each color (value) in the layer. In such a scheme set operations are carried out by taking unions and intersections of binary quadtrees. This paper presents an alternative database scheme where a layer is stored as a single multicolored quadtree, using a bit-list to store values at higher nodes in the tree. This allows the union of any set of values within a layer to be carried out by a single top down traversal of the tree, using parallel bit-masking operations. Experimental evidence is presented to show that these Bit-Mapped Multi-Colored quadtrees lead to faster colour selection and boolean overlay between layers in a GIS. Furthermore, the recent development of One-To-Four and Autumnal quadtrees have meant that it is now possible to exploit the hierarchical structure of regular quadtrees in GIS without paying an associated storage penalty. Experimental results using these developments are presented to show that representing a layer using a Bit-Mapped Multi-Colored quadtree is more space and time efficient for set operations in comparison to the use of a collection of binary quadtrees, one for each value in the layer. 相似文献