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以硝酸铜为铜源、硝酸铝为铝源,以草酸为沉淀剂,采用微波辅助合成p型半导体CuAlO_2纳米晶。通过X射线衍射仪(XRD)、傅里叶红外光谱(FT-IR)、紫外可见吸收光谱(UV-Vis)和激光粒度分析仪对其物相结构、化学性能、光学性质和粒径大小进行了表征分析,并对反应机理进行了讨论。研究了煅烧温度、原料配比等因素对产品结构的影响。结果表明:当Cu~(2+)和Al~(3+)摩尔比为1∶1,煅烧温度为1200℃时,样品为纯的CuAlO_2晶相,晶粒大小为41nm;样品含有与氢键缔合的OH基;其禁带宽度为4.53eV,与块体材料相比,发生了蓝移,其归因于晶粒减小而产生量子效应所致。 相似文献
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就某矿山变电站大型同步电动机难以启动的问题进行了多方面的计算,分析和论证,从中朝阳同难以启动的关键-供电线路阻抗偏大所致。提出了几种降一路阻抗值以解决电动机启动问题的方法。同时指出在上述条件下再采取降压措施以启动电动机的不妥当做法。 相似文献
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Li2Fe0.5Mn0.5SiO4 material was synthesized by a citric acid-assisted sol-gel method. The influence of the stoichiometric ratio value of n(citric acid) to n(Fe2+-Mn2+) on the electrochemical properties of Li2Fe0.5Mn0.5SiO4 was studied. The final sample was identified as Li2Fe0.5Mn0.5SiO4 with a Pmn21 monoclinic structure by X-ray diffraction analysis. The crystal phases components and crystal phase structure of the Li2Fe0.5Mn0.4SiO4 material were improved as the increase of the stoichiometric ratio value of n(citric acid) to n(Fe2+-Mn2+). Field-emission scanning electron microscopy verified that the Li2Fe0.5Mn0.5SiO4 particles are agglomerates of Li2Fe0.5Mn0.5SiO4 primary particles with a geometric mean diameter of 220 nm. The Li2Fe0.5Mn0.5SiO4 sample was used as an electrode material for rechargeable lithium ion batteries, and the electrochemical measurements were carried out at room temperature. The Li2Fe0.5Mn0.5SiO4 electrode delivered a first discharge capacity of 230.1 mAh/g at the current density of 10 mA/g in first cycle and about 162 mAh/g after 20 cycles at the current density of 20 mA/g. 相似文献
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对共沉淀法合成(Ni_(0.5)Mn_(1.5))(OH)_4前驱体的主要工艺参数展开了详细讨论,结果表明:当pH=10和螯合剂浓度为1mol/L时,其前驱体颗粒表现为球形且具有最高的密度;对终产物LiNi_(0.5)Mn_(1.5)O_4材料的物化性能和电化学性能进行了测试分析,扫描电镜和X射线衍射表征结果表明:其由直径为2~3μm、不规则形状的一次颗粒堆积成二次颗粒,产物不含有Li_(1-x)Ni_xO或NiO_x等不纯物;该样品具有较好的倍率和优秀的循环性能,可能归结于终产物具有较高的纯度,不含有杂相。 相似文献
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