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Wei C.,Chengdu University of Technology | Sang S.-H.,Chengdu University of Technology | Sang S.-H.,Key Laboratory of Sichuan Higher Education Institutions | Hu J.-X.,Chengdu University of Technology | And 3 more authors.
Asian Journal of Chemistry | Year: 2015

In this paper, the isothermal evaporation method was used to determine the metastable solubilities of strontium sulfate (SrSO4) at (278.2, 283.2, 303.2 and 323.2) K. During the evaporation progress, the concentrations of SrSO4 were measured at a period time and a set of the results were fitted to empirical equations of evaporating times. The metastable solubilities were determined by the maximum concentration and the metastable region of SrSO4 at 278.2 to 323.2 K was determined. By using simplified Pitzer equations and metastable solubilities at the given temperatures, the thermodynamic properties of SrSO4 (γ±, Φ, GE) were calculated and all the calculated results were compared with the stable values calculated by the literature solubilities in this work. Then the thermodynamic ion product (Qsp) of SrSO4 were calculated and compared with the thermodynamic solubility product (Ksp) of SrSO4 at different temperatures.

Zhang X.,Chengdu University of Technology | Zhang X.,Sichuan Zhiyuan Engineering Detecting Co. | Sang S.-H.,Chengdu University of Technology | Sang S.-H.,Key Laboratory of Sichuan Higher Education Institutions | And 4 more authors.
Journal of Chemical and Engineering Data | Year: 2014

The experimental studies on phase equilibria in the quaternary system Na+,K+//Cl-,B4O7 2--H2O at 323 K were done by the method of isothermal solution saturation. Solubilities of salts and densities of the solution were determined experimentally. The experimental results show that there is no double salt in the quaternary system Na+,K+//Cl -,B4O7 2--H2O at 323 K. The equilibrium phase diagram and the density-composition diagram were plotted based on the experimental data. In the phase diagram, the quaternary system has two invariant points, five univariant curves, and four crystallization fields corresponding to Na2B4O7·10H 2O, K2B4O7·4H2O, NaCl, and KCl. A brief discussion of the experimental results is described. © 2014 American Chemical Society.

Sang S.-H.,Chengdu University of Technology | Sang S.-H.,Key Laboratory of Sichuan Higher Education Institutions | Zhou M.-F.,Chengdu University of Technology | Zhou M.-F.,Key Laboratory of Sichuan Higher Education Institutions | And 4 more authors.
Journal of Solution Chemistry | Year: 2015

The mean activity coefficients of KCl in the KCl + K2B4O7 + H2O ternary systems were determined at total ionic strength ranging from (0.0100 to 1.0000) mol·kg-1 at 298.15 K by potential difference measurements from the electrochemical cell without liquid junction: $${\text{K-ISE}}\left| {{\text{KCl }}\left({m-{ 1} } \right),{\text{K}}-{ 2} {\text{B}}-{ 4} {\text{O}}-{ 7} \left({m-{ 2} } \right)} \right|{\text{ Cl-ISE}}$$ K-ISE KCl m 1, K 2 B 4 O 7 m 2 Cl-ISE. The mean activity coefficients of KCl were measured at different ionic strength fractions, $$y-{\text{B}}$$ y B, of K2B4O7 (with $$y-{\text{B}} = 0. 8, \, 0. 6, \, 0. 4, \, 0. 2,{\text{ and }}0. 0$$ y B = 0.8, 0.6, 0.4, 0.2, and 0.0). The experimental results showed that K-ISE and Cl-ISE in this work had good Nernstian responses, and the mean activity coefficients of KCl in KCl + K2B4O7 + H2O mixtures were calculated using the Nernst equation. Mixing interaction parameters of $$\theta-{{{\text{Cl}}^{ - } {\cdot} {\text{B}}-{4} {\text{O}}-{5} ({\text{OH}})-{4}^{2 - } }}$$ θ Cl - · B 4 O 5 (OH) 4 2 - and $$\psi-{{{\text{K}}^{ + } {\cdot} {\text{Cl}}^{ - } {\cdot} {\text{B}}-{4} {\text{O}}-{5} ({\text{OH}})-{4}^{2 - } }}$$ ψ K + · Cl - · B 4 O 5 (OH) 4 2 - in Pitzer's equation were evaluated from the present measurements of the mean activity coefficients of KCl. In addition, the osmotic coefficients, water activity, and the excess Gibbs energy of this system were calculated by Pitzer's equations. © 2015 Springer Science+Business Media New York.

Zhang K.-J.,Chengdu University of Technology | Zhang K.-J.,State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation | Zhang K.-J.,Key Laboratory of Sichuan Higher Education Institutions | Sang S.-H.,Chengdu University of Technology | And 8 more authors.
Journal of Chemical and Engineering Data | Year: 2013

The solubilities and densities of solid-liquid equilibria in the quaternary system KCl-KBr-K2SO4-H2O at 348 K were determined experimentally by using an isothermal solution saturation method. According to the experimental data, the phase diagram of the quaternary system was plotted. In the equilibrium phase diagram of the quaternary KCl-KBr-K 2SO4-H2O system at 348 K, there are one univariant dissolution curve and two crystallization fields corresponding to K(Cl, Br) and K2SO4, and no invariant point has been found in this quaternary system. The quaternary system contained solid solution K(Cl, Br). The density values in the equilibrium solution increase with the increase of potassium bromide concentration and decrease with the increase of potassium chloride concentration. © 2012 American Chemical Society.

Guan D.G.,Chengdu University of Technology | Guan D.G.,Key Laboratory of Sichuan Higher Education Institutions | Sun Y.,Chengdu University of Technology | Xu G.L.,Chengdu University of Technology | And 7 more authors.
Applied Mechanics and Materials | Year: 2013

A new kind of the electromagnetic shielding composite coatings with high performance was prepared using the Ni-Cu-coated glass fibers and nickel powders as fillers and using epoxy resin as binder. The effects of the fibers on the conductivity and electromagnetic shielding effectiveness of the coatings were studied. The study results show as follows: 1) when the optimum ratio of the fillers to epoxy resin is 4:1, the coatings containing 6 wt% the Ni-Cu-coated glass fibers has best conductivity and electromagnetic shielding effectiveness; when the coating layer thickness is 300 μm, the shielding effectiveness of the coatings is up to 43.71-52.31 dB and increased an average of 13.94 dB compared with the nickel powders/ epoxy resin electromagnetic shielding coatings in the frequency range of 0.3-1000 MHz. This offers a new idea to enhance the added value of the glass fibers and the prevention of electromagnetic environmental pollution. © (2013) Trans Tech Publications, Switzerland.

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