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Xiaofei Bie Chunzhong Wang H. Ehrenberg Yingjin Wei Gang Chen Xing Meng Guangtian Zou Fei Du 《Solid State Sciences》2010,12(8):1364-1367
ZnO nanoflowers are synthesized by hydrothermal method. The morphology of ZnO is captured by SEM, TEM and HRTEM, which is composed of closely packed nanorods of about 100 nm in diameter and 1 μm in length. The ZFC/FC curves show superparamagnetic features. The abnormal increase in magnetization curves below 14 K comes from the isolated vacancy clusters with no interaction. The magnetic hysteresis at 300 K displays saturation state and confirms room-temperature ferromagnetism. While the magnetic hysteresis at 5 K shows nonsaturation state due to the enhanced effects of vacancy clusters. The O 1s XPS results can be fitted to three Gaussian peaks. The existence of medium-binding energy located at 531.16 eV confirms the deficiency of O ions at the surface of ZnO nanoflowers. 相似文献
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Tao Jiang Fei Du Kejin Zhang Yingjin Wei Zhe Li Chunzhong Wang Gang Chen 《Solid State Sciences》2010,12(9):1672-1676
Carbon coated and carbon free Li3V2(PO4)3 cathode materials were prepared by carbothermal reduction and H2 reduction methods, respectively. The carbon free material had a grain size about 1 μm whereas the carbon coated material was less than 100 nm. The surface carbon layer enhanced the electronic conductivity of Li3V2(PO4)3 by five orders of magnitude. In addition, the surface carbon layer also prevented the formation of SEI film, decreased the charge transfer resistance and increased the chemical diffusion coefficient of Li+ ions. All of these advantages improved the electrochemical performance of Li3V2(PO4)3. As most of intercalation materials, the low temperature performance of Li3V2(PO4)3 was poorer than that at room temperature. This was attributed to the electrochemical sluggish kinetics which caused higher charge transfer resistance and smaller chemical diffusion coefficient. The carbon coating technique was effective to eliminate these sluggish kinetics, and then improved the low temperature performance of Li3V2(PO4)3. 相似文献
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Preparation and Electrochemical Properties of Tin–Iron–Carbon Nanocomposite as the Anode of Lithium‐Ion Batteries
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Dr. Xu Yang Dr. Rongyu Zhang Dr. Xiaofei Bie Prof. Chunzhong Wang Malin Li Dr. Nan Chen Prof. Yingjin Wei Prof. Gang Chen Dr. Fei Du 《化学:亚洲杂志》2015,10(11):2460-2466
Tin–iron–carbon nanocomposite is successfully prepared by a sol–gel method followed by a chemical vapor deposition (CVD) process with acetylene gas as the carbon source. The structural properties, morphology, and electrochemical performances of the nanocomposite are comprehensively studied in comparison with those properties of tin–carbon and iron–carbon nanocomposites. Sheet‐like carbon architecture and different carbon contents are induced thanks to the catalytic effect of iron during CVD. Among three nanocomposites, tin–iron–carbon demonstrates the highest reversible capacity of 800 mA h g?1 with 96.9 % capacity retention after 50 cycles. It also exhibits the best rate capability with a discharge capacity of 420 mA h g?1 at a current density of 1000 mA g?1. This enhanced performance is strongly related to the carbon morphology and content, which can not only accommodate the large volume change, but also improve the electronic conductivity of the nanocomposite. Hence, the tin–iron–carbon nanocomposite is expected to be a promising anode for lithium‐ion batteries. 相似文献
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基于Web技术的网络拓扑图生成方法的研究 总被引:5,自引:0,他引:5
综合采用提取路由表和地址转发表的方法,对网络逻辑拓扑结构和物理拓扑结构进行自动探索,提出了用于优化显示网络拓扑图的一种显示算法,采用Java技术实现了基于Web的网络拓扑图,并对在实现过程中遇到的问题进行了探讨。试验结果表明,由此生成的网络拓扑图准确、美观、能够实现跨平台和跨区域的管理。 相似文献
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