Isopiestic molalities, vapor pressures and osmotic coefficients of aqueous Li 2B 4O 7 solutions from 0.027 5 to 2.939 7 mol/kg were determined at 298.15 K by using an improved apparatus. The rule of the changes in vap...Isopiestic molalities, vapor pressures and osmotic coefficients of aqueous Li 2B 4O 7 solutions from 0.027 5 to 2.939 7 mol/kg were determined at 298.15 K by using an improved apparatus. The rule of the changes in vapor pressure over aqueous Li 2B 4O 7 solutions was revealed, which indicated that the bond of borate anions with water are better than that of NaCl. The different formation reaction equilibria for the species containing boron of boric acid and borate anions B(OH) - 4, B 3O 3(OH) - 4 and B 4O 5(OH) 2- 4 in Li 2B 4O 7(aq) solutions were taken into account. The stoichiometric equilibrium constants for the formation reactions of the boron species and the ion-interaction parameters were estimated simultaneously by using Pitzer equations of osmotic coefficient with minor modifications. Sixteen parameters were obtained with a standard deviation 0.005 5 for the ion-interaction model.展开更多
To provide an accurate prediction of the product component dependence of temperature and pressure in vacuum distillation and give convenient and efficient guidance for the designing of the process parameters of indust...To provide an accurate prediction of the product component dependence of temperature and pressure in vacuum distillation and give convenient and efficient guidance for the designing of the process parameters of industrial production, according to the molecular interaction volume model(MIVM), the separation coefficient(β) and vapor-liquid equilibrium composition of Au-Ag alloy at different temperatures are calculated. Combined with the vapor-liquid equilibrium(VLE) theory, the VLE phase diagrams, including the temperature-composition(T-x) and pressure-composition(p-x) diagrams of Au-Ag alloy in vacuum distillation are plotted. The triple points and condensation temperatures of gold and silver vapors are calculated as well. The results show that the β decreases and the contents of gold in vapor phase increase with the distillation temperature increasing. Low pressures have positive effect on the separation of Ag and Au. The difference between the condensation temperatures of gold and silver is about 450 K in the pressure range of 1-10 Pa.展开更多
We study the effect of two non-interacting impurity atoms near by a one-dimensional nanowire, which is modeled as a tight-binding hopping model. The virtual single-electron hopping between two impurities will induce a...We study the effect of two non-interacting impurity atoms near by a one-dimensional nanowire, which is modeled as a tight-binding hopping model. The virtual single-electron hopping between two impurities will induce an additional energy depending on the distance of two impurities, which gives a electronic Casimir–Polder effect. We find that the Casimir–Polder force between the two impurities decreases with the impurity-impurity distance exponentially.And the effects of nanowire and finite temperature on the Casimir–Polder force are also discussed in detail, respectively.展开更多
文摘Isopiestic molalities, vapor pressures and osmotic coefficients of aqueous Li 2B 4O 7 solutions from 0.027 5 to 2.939 7 mol/kg were determined at 298.15 K by using an improved apparatus. The rule of the changes in vapor pressure over aqueous Li 2B 4O 7 solutions was revealed, which indicated that the bond of borate anions with water are better than that of NaCl. The different formation reaction equilibria for the species containing boron of boric acid and borate anions B(OH) - 4, B 3O 3(OH) - 4 and B 4O 5(OH) 2- 4 in Li 2B 4O 7(aq) solutions were taken into account. The stoichiometric equilibrium constants for the formation reactions of the boron species and the ion-interaction parameters were estimated simultaneously by using Pitzer equations of osmotic coefficient with minor modifications. Sixteen parameters were obtained with a standard deviation 0.005 5 for the ion-interaction model.
基金supported by the National Natural Science Foundation of China (No.52064029)Yunling Scholarship of Yunnan Province Ten-Thousand Plan,China (No.KKRC201952012)Yunnan Province Ten Thousand Talents Program-Youth Top Talent Project,China (No.2018-73)。
文摘To provide an accurate prediction of the product component dependence of temperature and pressure in vacuum distillation and give convenient and efficient guidance for the designing of the process parameters of industrial production, according to the molecular interaction volume model(MIVM), the separation coefficient(β) and vapor-liquid equilibrium composition of Au-Ag alloy at different temperatures are calculated. Combined with the vapor-liquid equilibrium(VLE) theory, the VLE phase diagrams, including the temperature-composition(T-x) and pressure-composition(p-x) diagrams of Au-Ag alloy in vacuum distillation are plotted. The triple points and condensation temperatures of gold and silver vapors are calculated as well. The results show that the β decreases and the contents of gold in vapor phase increase with the distillation temperature increasing. Low pressures have positive effect on the separation of Ag and Au. The difference between the condensation temperatures of gold and silver is about 450 K in the pressure range of 1-10 Pa.
基金Supported by National Natural Science Foundation of China under Grants Nos.11175044,11105021,11204028,and 11547242the Natural Science Foundation of Jilin Province under Grant No.201115007+1 种基金the Foundation of Changchun University of Science and Technology under Grant No.XQNJJ-2015-04supported by China Postdoctoral Science Foundation under Grant No.2015M580966
文摘We study the effect of two non-interacting impurity atoms near by a one-dimensional nanowire, which is modeled as a tight-binding hopping model. The virtual single-electron hopping between two impurities will induce an additional energy depending on the distance of two impurities, which gives a electronic Casimir–Polder effect. We find that the Casimir–Polder force between the two impurities decreases with the impurity-impurity distance exponentially.And the effects of nanowire and finite temperature on the Casimir–Polder force are also discussed in detail, respectively.
