排序方式: 共有9条查询结果,搜索用时 18 毫秒
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分光光度法测定水杨酸的含量 总被引:2,自引:0,他引:2
水杨酸与醋酸铜在 p H为 5 .8~ 6.0时 ,能迅速形成 1种稳定的黄绿色络合物 ,此络合物在波长40 0 nm处有最大吸收 ,ε为 2 0 1 L/(cm· mol) ,在 0 .2~ 4.0 mg/m L范围内遵守比耳定律 ,并能稳定 3 0 h.在以水杨酸为原料电化学还原制备水杨醛的电解液中 ,水杨醛和硼酸影响此络合物的吸光度 ,但可以采用乙醚萃取的方法消除影响 相似文献
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微波法制备掺碳LiFePO4正极材料 总被引:7,自引:0,他引:7
Cathode material LiFePO4 of lithium-ion battery was synthesized by microwave heating. The “carbon-included” LiFePO4 with improved conductivity was synthesized by the addition of graphite. And the influence of microwave-heating time on structure, morphology and charge/discharge performance of the products was discussed. The results of XRD, SEM, XPS, CV and charge/discharge testing measurements showed that the LiFePO4 product after 9 min in microwave oven had more advantages than other products. 相似文献
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锂离子二次电池正极材料LiVPO4F的制备及其电化学性能的研究 总被引:3,自引:0,他引:3
A new cathode material, LiVPO4F, has been synthesized through two steps of solid-state reactions. In the first step, vanadium pentoxide, ammonium dihydrogen phosphate, and a high surface area carbon were pre-heated at 300 ℃ and reacted at 750 ℃ under an inert atmosphere to yield the trivalent vanadium phosphate VPO4. In the second step, the product LiVPO4F was synthesized by the reaction with VPO4 and LiF. The LiVPO4F was characterized by X-ray diffraction, scanning electron microscopy, cyclic voltammetry and charge/discharge testing measurements. The LiVPO4F is triclinic crystalline system. At 0.1 C rate, the first charge/discharge capacities were 150.1 mAh·g-1 and 132.6 mAh·g-1; At 0.2 C rate, the first charge/discharge capacities were 142.9 mAh·g-1 and 125.2 mAh·g-1. The LiVPO4F from this work has higher charge/discharge voltage 4.3 V and 4.1 V, respectively. 相似文献
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哌啶酮阴极电还原合成哌啶醇 总被引:1,自引:1,他引:0
常温、常压下采用电化学法合成哌啶醇,反应选择性好,产品单一,易分离,且电解液可循环使用.以锌作阴极材料,研究了电量、电流密度、氢氧化钠浓度、乙醇浓度、哌啶酮浓度对哌啶酮转化率的影响,得出最佳反应条件:电量1.1F/mol,电流密度300A/m2,0.50mol/L的氢氧化钠,φ(乙醇)为30%,哌啶酮浓度1.0mol/L.在此条件下,哌啶醇的平均产率为95.40%,经分离,产品纯度达99%以上. 相似文献
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草酸电还原制乙醇酸化学分析方法的研究 总被引:1,自引:0,他引:1
草酸阴极还原制乙醇酸的电解液可用简便的化学分析方法测定,其中草酸的定量可以钙盐沉淀后用高锰酸钾法测定;乙醛酸的定量用国家标准附以酸度计控制终点来测定;乙醇酸的定量用邻苯二甲酸酐来测定.本化学分析方法具有快速、简单、可靠的特点,具有重要的工业价值. 相似文献
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草酸电还原研制乙醇酸 总被引:3,自引:0,他引:3
采用循环伏安(CV)法确定了草酸可以还原为乙醇酸,以铅作阴极材料的阳离子交换膜电解槽,电解草酸研制乙醇酸,并且以电流密度、电量、温度和电解液的流速做了4因素4水平的正交实验,得出了最佳工艺条件,产率达88%以上。 相似文献
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采用高温固相法2步合成了掺Cr的锂离子电池正极材料LiV1-xCrxPO4F(x=0,0.01,0.03,0.05,0.07),XRD测试表明LiV1-xCrxPO4F属三斜晶系。通过恒电流充放电,循环伏安和交流阻抗实验表明:掺Cr后LiVPO4F正极材料更有利于锂离子的嵌入和嵌出,材料的放电容量和循环性能进一步提高,例如,铬掺杂的LiVPO4F样品在室温、0.2 C倍率下充放电,循环50周后容量在110 mAh·g-1以上。文中还讨论了充放电容量随掺Cr量的关系,nCr含量为0.03的LiV1-xCrxPO4F有着较高的放电平台和良好的循环稳定性。 相似文献
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