Kinetic study of Y, Ba, Cu oxalates and coprecipitated Y-Ba-Cu oxalate
摘要:
The kinetics of the decomposition of Y, Ba and Cu oxalates and coprecipitanted Y-Ba-Cu oxalate was investigated under a nitrogen atmosphere on the basis of dynamic thermogravimetric data, the average activation energies of the decomposition of Y, Ba and Cu oxalates were obtained from the slopes of the T. Ozawa plot.The average activation energies for the dehydration of these oxalate and coprecipitated Y-Ba-Cu oxalate were also evaluated from the thermogravimetric curves.
The crystalstructure of bariumoxalatehydrate, BaC204.2H20, was reinvestigated using a synchrotronX-raypowderpattern and a single crystalX-ray data set. The compound is monoclinic, a = 7.538(l), b = 11.062(l), c = 7.105(1) angstroms, beta = 105.42(l)“, space group P21/c, with Z = 4. The precision of the structure arrived at with the synchrotronX-raypowderpattern is not as high as that obtained
使用同步加速器 X 射线粉末图案和单晶 X 射线数据集重新研究草酸钡水合物 BaC2O4.2H2O 的晶体结构。该化合物为单斜晶系,a = 7.538(l), b = 11.062(l), c = 7.105(1) 埃,β = 105.42(l)",空间群 P21/c,Z = 4。用同步加速器 X 射线粉末图得到的结构不如用单晶 X 射线数据得到的结构高。钡原子与 键合。草酸根离子和水分子之间具有 2.71(l)-2.97(l) 埃范围内的 9 个钡氧键。该结构具有范围为 2.72(2)-2.91(2) 埃的氢键,并且草酸根离子与平面性的偏差很小。
The thermal decomposition of oxalates. Part 18. The preparation and thermal decomposition of acid barium oxalates
作者:Asif.S. Bhatti、David Dollimore、Albert Fletcher
DOI:10.1016/0040-6031(84)87133-6
日期:1984.7
study entails the preparation of variousforms of barium oxalate. The main method of preparation used was the simultaneous mixing of equimolar solutions of barium chloride and oxalic acid over a range of concentrations of starting materials from 0.2 to 1.6 mol. Each compound was analysed for its percentage of barium, oxalate and water content. Thermogravimetric and differential thermal analysis data were
BaCrO4 microdiscs composed of multi-layered microplates were successfully synthesized by a facile oxalate-assisted precipitation method. Based on time-dependent experiments, a dissolution–recrystallization–self-assembly process has been proposed.
Grain size dependence of the critical current density in YBa<sub>2</sub>Cu<sub>3</sub>O<sub><i>x</i></sub>superconductors
作者:M. Kuwabara、H. Shimooka
DOI:10.1063/1.102373
日期:1989.12.25
The grainsizedependence of the criticalcurrentdensity in bulk single‐phase YBa2Cu3Ox ceramics was investigated. The grainsize of the materials was changed to range approximately from 1.0 to 25 μm by changing the conditions of power processing and sintering, associated with an increase in the sintered density of the materials with increasing grainsize. The criticalcurrentdensity has been found