Li_(1-x)Cr_xFePO_4的微波合成研究

采用机械球磨结合微波法合成了Cr3+掺杂锂离子电池正极材料Li1-xCrxFePO4。通过X射线衍射(XRD)、扫描电镜(SEM)和恒电流充放电测试研究了Cr3+掺杂方式和掺杂量对样品的物相结构、形貌和电化学性能的影响。实验结果表明,微波法可以快速合成Li1-xCrxFePO4正极材料;以共沉淀掺杂方式合成的样品Li0.99Cr0.01-FePO4具有最好的电化学性能,在室温下以20mA/g进行充放电测试,其首次放电容量为153.59mAh/g,10次循环之后还有149.29mAh/g,容量保持率为97.20%。     

Li-Mn-Ti复合氧化物的结构及其在酸介质中的稳定性

采用固相法合成系列Li-Mn-Ti复合氧化物(理论化学式为LiTi<,x>Mn<,2-x>p<,4>,0≤x≤1);利用热重-差示扫描量热法(TG-DSC)、X射线衍射(XRD)和扫描电子显微镜(SEM)等对其结构和形貌进行表征,并通过酸浸实验考察其在弱酸性介质中的稳定性.结果表明:当x≤0.5时,Ti能完全地纳入尖晶石晶格,并使晶胞参数增大、晶粒变小;Li-Mn-Ti复合氧化物酸浸前、后能够保持尖晶石的结构和形貌,具有结构稳定性,但其化学稳定性还有待进一步提高.     

腐蚀监测用探头的研究

研制了Ａｇ／ＡｇＣｌ固体参比电极，并讨论了影响电极稳定性和温度系数的因素，同时制备了以固体参比电极为基础，中心嵌入与研究对象同材质的金属电极作为研究电极，外层以不锈钢作辅助电极的腐蚀监测探头。该探头可用于低阻和高阻介质的电化学测量。     

Preparation of cobalt-modified magnetite and its magnetic properties

Magnetite was modified by reaction with alkaline solution containing Co^2 and Fe^2 to obtain a cobalt ferrite layer on the surface of particles. The influences of modification conditions on the properties were investigated. The as-prepared particles were characterized by X-ray diffraction(XRD) and transmission electron microscope(TEM). The results show that pH value influences the particles composition directly, the desirable CoFe2O4 is obtained as pH value is 12. The coercivity of particles increases with the increase of cobalt content, and the cobalt efficiency reaches a maximum value at cobalt content of 2.71% (mass fraction). With cobalt modification, the magnetite particles have the similar lattice constant and structure to that without cobalt modification, and the squareness ratio is almost 0.5. The increase of the coercivity is attributed to the uniaxial magnetic anisotropy and magnetocrystalline anisotropy of cobalt-ferrite itself.     

Asymmetric synthesis of 3β-acetoxy-17,17-ethylendioxy-15β,16β-methylene-5-androsten-7β-ol

3β-acetoxy-17,17-ethylendioxy-15β,16β-methylene-5-androsten-7β-ol( Ⅰ ) was prepared by 3 steps from 3β-acetoxy-15β,16β-methylene-5-androsten-17-one ( Ⅱ ) with overall yield of 52.7%. Thus, interaction of ethylene glycol and material ( Ⅱ ) gave 3β-acetoxy- 17,17-ethylendioxy-15β,16β-methylene-5-androsten ( Ⅲ ) which was subsequently oxidated and stereoselectively reduced to produce compound( Ⅰ ). The normal influencing factors, such as the types of oxidants and reductives, the mole ratio of reactants, the reaction temperature, and the addition ways of reactants, in oxidation and reduction were discussed. The results show that the oxidation rate order is CrO3-C5 H5 N (1: 1, mole fraction)＞CrO3-C5H5 N(1: 2)＞ (C5H5NH)2 Cr2O7 in terms of the oxidant, the yield of the oxidation becomes higher with increasing the oxidant stoichiometry and raising the reaction temperature. And the optimum condition is that the reaction temperature is at 30 ℃, and n(Ⅲ)/n(CrO3-C5H5N(1: 2))=1: 20. The yield of the -7β alcohol order with Li[Al(OC(CH3)3)3H] (e. G. 78. 6%) is more than that with NaBH4 (e. G. 14. 5%) in terms of the reductive agent and the reduction rate decreases in the course of reaction. The compound (Ⅰ) is characterized by 1R and MS.     

电力系统电压控制专家系统程序开发

本文依据易于实现的灵敏度方法，开发电力系统电压控制专家系统，该专家系统程序用Turbo prolog语言编号，并调用Fortran语言编写的潮流程序。全部程序都在PC机上实现，最后用实例测试该专家系统的正确性。     

Kinetics of Fe_3O_4 formation by air oxidation

1　INTRODUCTIONFe3O4 hasanumberofnovelpropertiesandper formances ,itsuniquemagnetic ,thermalandtribolog icalpropertiesmakeitanewtypeofmaterialspromis inginvariousapplicationssuchaspigment,toner ,in formationstorage ,ferrofluids ,bioprocessing ,elec tronicsandcatalyst[1,2 ] .Owingtothewideapplica tion ,majorityofresearchersfocusedontheprepara tionmethodsofmagnetite[310 ] ,however ,themech anismandkineticsofFe3O4 formationwerescarcelystudied .Thekineticsandmechanismofoxyhydrox idesformatio…     

氧化铁黑颜料的制备

采用硫酸浸出黄铁矿烧渣的FeSO4浸出作为原料,选用氧化沉淀法制备氧化铁黑颜料,所得产品的性能指标达到HG／T2250－91一级品标准,介绍了该制法的反应原理及工艺流程。讨论了氧化反应温度、pH值、空气流速、硫酸亚铁浓度、Fe^3 /Fe^2 比值对产品性能的影响。     

硫铁矿烧渣制备静电复印显影剂用Fe3O4

硫铁矿烧渣是生产硫酸时产生的固体废弃物。硫铁矿烧渣经硫酸浸出,用机械活化的硫铁矿还原,过滤得到硫酸亚铁溶液。以此溶液为原料,采用空气氧化法制备显影剂用Fe3O4。研究了FeSO4浓度、碱种类、pH值、空气流量和温度对产品性能的影响,用XRD、SEM、粒度分析和磁性能测试等手段对产品进行了表征。结果表明,在最佳工艺条件下得到了球形Fe3O4,粒度分布范围为0.1～0.5μm,磁饱和强度为96.2Am2/kg,矫顽力为10.7kA/m,满足静电复印显影剂对磁粉的要求。