The artificial neural network (ANN) and the pattern recognition were applied to study the correlation of enthalpies of fusion for divalent rare earth halides with their microstructural parameters,such as ionic radius ...The artificial neural network (ANN) and the pattern recognition were applied to study the correlation of enthalpies of fusion for divalent rare earth halides with their microstructural parameters,such as ionic radius and electronegativity. The model,represented by a back-propagation netal network, was trained with a 12 set of published data for divalent rare earth halides and then was used to predict the unknown ones. Also the criterion equations were ptesented to determine the enthalpies of fuSion for divalent rare earth halides using pattern recognition in mis work. The results from the model in ANN and criterion equations are in very good agreement with reference data.展开更多
Introduction CsEuF;, CsYbF;and RbYbF;are the first members of divalent rare earth ternary halides obtained via reduction of trivalent rare earth halides by alkali metals. Recently we adopted a new synthesis route in p...Introduction CsEuF;, CsYbF;and RbYbF;are the first members of divalent rare earth ternary halides obtained via reduction of trivalent rare earth halides by alkali metals. Recently we adopted a new synthesis route in preparing divalent rare earth chlorides and bromides and the five titled compounds were suc-展开更多
This work dealt with the computation of the mean activity coefficients of rare-earth halide aqueous solutions at 25℃, by means of the Quasi Random Lattice（QRL） model. The osmotic coefficients were then calculated c...This work dealt with the computation of the mean activity coefficients of rare-earth halide aqueous solutions at 25℃, by means of the Quasi Random Lattice（QRL） model. The osmotic coefficients were then calculated consistently, through the integration of the Gibbs-Duhem equation. Using of QRL was mainly motivated by its dependence on one parameter, given in the form of an electrolyte-dependent concentration, which was also the highest concentration at which the model could be applied. For all the electrolyte solutions here considered, this parameter was experimentally known and ranged from 1.5 to 2.2 mol/kg, at 25 ℃.Accordingly, rare- earth halide concentrations from strong dilution up to 2 mol/kg about could be considered without need for best-fit treatment in order to compute their osmotic and mean activity coefficients. The experimental knowledge about the parameter was an advantageous feature of QRL compared to existing literature models. Following a trend already observed with low charge electrolytes,a satisfactory agreement was obtained with the experimental values for all the investigated rare-earth chlorides and bromides. For the sake of compactness, in this work the considered rare-earth halides were all belonging to the P63/m space group in their crystalline（anhydrous） form.展开更多
Based on the thermodynamically self-consistent analysis and optimization of three sub-binary systems of the ternary system PrCl_3-CaCl_2-MgCl_2,the thermodynamics of this ternary system has been studied.Using Hillert ...Based on the thermodynamically self-consistent analysis and optimization of three sub-binary systems of the ternary system PrCl_3-CaCl_2-MgCl_2,the thermodynamics of this ternary system has been studied.Using Hillert model and taking MgCl_2 as an asymmetric component,the PrCl_3-CaCl_2-MgCl_2 phase diagram has been calculated.The agreement between calculated and measured compositions and temperatures at deflecting points on liquidus is good.The system is a simple eutectic one with a eutectic point at 26.0mol% PrCl_3, 41.5mol% CaCl_2,32.5mol% MgCl_2;560℃(calculated)and 26.0mol% PrCl_3,39.4mol% CaCl_2,34.6mol% MgCl_2;546℃(measured),respectively.展开更多
文摘The artificial neural network (ANN) and the pattern recognition were applied to study the correlation of enthalpies of fusion for divalent rare earth halides with their microstructural parameters,such as ionic radius and electronegativity. The model,represented by a back-propagation netal network, was trained with a 12 set of published data for divalent rare earth halides and then was used to predict the unknown ones. Also the criterion equations were ptesented to determine the enthalpies of fuSion for divalent rare earth halides using pattern recognition in mis work. The results from the model in ANN and criterion equations are in very good agreement with reference data.
文摘Introduction CsEuF;, CsYbF;and RbYbF;are the first members of divalent rare earth ternary halides obtained via reduction of trivalent rare earth halides by alkali metals. Recently we adopted a new synthesis route in preparing divalent rare earth chlorides and bromides and the five titled compounds were suc-
文摘This work dealt with the computation of the mean activity coefficients of rare-earth halide aqueous solutions at 25℃, by means of the Quasi Random Lattice（QRL） model. The osmotic coefficients were then calculated consistently, through the integration of the Gibbs-Duhem equation. Using of QRL was mainly motivated by its dependence on one parameter, given in the form of an electrolyte-dependent concentration, which was also the highest concentration at which the model could be applied. For all the electrolyte solutions here considered, this parameter was experimentally known and ranged from 1.5 to 2.2 mol/kg, at 25 ℃.Accordingly, rare- earth halide concentrations from strong dilution up to 2 mol/kg about could be considered without need for best-fit treatment in order to compute their osmotic and mean activity coefficients. The experimental knowledge about the parameter was an advantageous feature of QRL compared to existing literature models. Following a trend already observed with low charge electrolytes,a satisfactory agreement was obtained with the experimental values for all the investigated rare-earth chlorides and bromides. For the sake of compactness, in this work the considered rare-earth halides were all belonging to the P63/m space group in their crystalline（anhydrous） form.
基金Project Supported by National Natural Science Foundation of China
文摘Based on the thermodynamically self-consistent analysis and optimization of three sub-binary systems of the ternary system PrCl_3-CaCl_2-MgCl_2,the thermodynamics of this ternary system has been studied.Using Hillert model and taking MgCl_2 as an asymmetric component,the PrCl_3-CaCl_2-MgCl_2 phase diagram has been calculated.The agreement between calculated and measured compositions and temperatures at deflecting points on liquidus is good.The system is a simple eutectic one with a eutectic point at 26.0mol% PrCl_3, 41.5mol% CaCl_2,32.5mol% MgCl_2;560℃(calculated)and 26.0mol% PrCl_3,39.4mol% CaCl_2,34.6mol% MgCl_2;546℃(measured),respectively.
