Oxygen isotope fractionation between coexisting minerals in slowly cooled rocks conveys information about their cooling history. By using the fast grain boundary(FGB) model to simulate closed-system diffusive exchange...Oxygen isotope fractionation between coexisting minerals in slowly cooled rocks conveys information about their cooling history. By using the fast grain boundary(FGB) model to simulate closed-system diffusive exchange of oxygen isotopes between coexisting minerals, I show that the apparent equilibrium temperatures(Tae) by the mineral pair with the largest isotopic fractionation(PLIF) always lies between the closure temperatures(Tc) of those two minerals. Therefore, when the rate of oxygen diffusion and hence Tc for the PLIF chance to be comparable(such as in the case of quartz and magnetite), Tae will serve as a good approximation of Tc regardless of variation in mineral proportions. The specialty of the PLIF in constraining Tae within their Tc range can be generalized to other stable isotope systems and element partitioning. By approximating Tc with Tae and inverting Dodson's equation, the cooling rate of plutonic or metamorphic rocks can be inferred.展开更多
Ironmaking is the art of removal the arch-enemy oxygen from iron ore by means of carbon reduction and thus producing hot metal.Steelmaking is the art of removing carbon from liquid hot metal by means of best friend pu...Ironmaking is the art of removal the arch-enemy oxygen from iron ore by means of carbon reduction and thus producing hot metal.Steelmaking is the art of removing carbon from liquid hot metal by means of best friend pure oxygen,followed by alloying and deoxidation-where oxygen returns to be the arch-enemy.Non-metallic particles in steel such as oxides can have a detrimental effect on the steel product properties in terms of formability,strength and surface properties.An overview of the battle for clean steel production is given based on the experience of the author in industry as well as university research.展开更多
The interfacial oxygen transfer rate is one of the main factors to control the composition of alloys.The commonly employed method of studying the interfacial oxygen transfer rate is the chemical composition analysis;h...The interfacial oxygen transfer rate is one of the main factors to control the composition of alloys.The commonly employed method of studying the interfacial oxygen transfer rate is the chemical composition analysis;however,it is difficult to be studied in situ.Here,a new method of measuring the oxygen transfer rate at the gas-slag and slag-metal interfaces was reported based on electrochemical analyses.The interfacial oxygen transfer rate in the smelting process of Inconel 718 superalloy was investigated at 1723,1773,1823,and 1873 K.The experimental results show that the electrochemical method can measure the real-time oxygen content;hence,this method is promising in controlling the oxygen content in alloys.As the temperature increased,both the equilibrium oxygen content and the rate of oxygen absorption increased significantly,and the increase was the most obvious when the temperature was 1873 K.The possible reason is that the increase in temperature weakens the mass transfer resistance of the electric double layer at the interface,thus accelerating the oxygen transfer rate.展开更多
TiClx （x=2.17） was prepared by using titanium sponge to reduce the concentration of TiCl4 in a NaCl-KCl melt under negative pressure. The as-prepared NaCl-KCl-TiClx melt was employed as the electrolyte, and two para...TiClx （x=2.17） was prepared by using titanium sponge to reduce the concentration of TiCl4 in a NaCl-KCl melt under negative pressure. The as-prepared NaCl-KCl-TiClx melt was employed as the electrolyte, and two parallel crude titanium plates and one high-purity titanium plate were used as the anode and cathode, respectively. A series of electrochemical tests were performed to investigate the influence of electrolytic parameters on the current efficiency and quality of cathodic products. The results indicated that the quality of cathodic products was related to the current efficiency, which is significantly dependent on the current density and the initial concentration of titanium ions. The significance of this study is the attainment of high-purity titanium with a low oxygen content of 30× 10^-6.展开更多
A high temperature equilibration experiment was carried out to investigate the effect of oxygen partial pres- sure on the phase equilibria and liquidus in CaO-Al2O3- FeOx system with the intermediate oxygen partial pr...A high temperature equilibration experiment was carried out to investigate the effect of oxygen partial pres- sure on the phase equilibria and liquidus in CaO-Al2O3- FeOx system with the intermediate oxygen partial pressures of 10.13 Pa and 1.01 × 10^-3 Pa. The equilibrated phases and their compositions of the quenched samples were analyzed by using SEM/EPMA （Scanning Electron Microscope/Electron Probe Micro Analysis） and XRD （X Ray Diffraction）. The phase equilibrium results include two cases, the two phase coexistence and the three-phase coexistence in the high Al2O3 region with oxygen partial pressure of either 10.13 Pa or 1.01 × 10^-3 Pa. Effects of oxygen partial pressure and temperature on the liquidus along the primary phase fields of CaO · Al2O3 and CaO · 2Al2O3 were nota hle. With the decrease of oxygen partial pressure, the liquid area expands and the liquidus of CaO · Al2O3 and CaO · 2Al2O3 primary fields moves to the Al2O3-FeOx region. On the other hand, the liquid area of CaO Al2O3-FeOx sys tem extends extremely to the high Al2O3 region with the temperature increasing from 1 400 to 1 500℃, especially at lower oxygen partial pressure. The present experiment results are in good agreement with the calculated ones by FactSage.展开更多
Thimble zirconia oxygen sensors were prepared with yttria stabilized zirconia(YSZ). The surfaces of the electrode, electrolyte and their interface were observed by scanning electron microscope(SEM). The sensor was exa...Thimble zirconia oxygen sensors were prepared with yttria stabilized zirconia(YSZ). The surfaces of the electrode, electrolyte and their interface were observed by scanning electron microscope(SEM). The sensor was examined with engine bench test to evaluate the essential performance. The results show that the oxygen sensor has good performance, which can meet the demand of practical applications. Chemical equilibrium theory was introduced to explain electromotive force of the sensors and the influence of temperature on the signals. The educed theoretical model of electromotive force agrees well with testing results.展开更多
Oxygen isotope fractionation is studied during the synthesis of kaolinite under controlled conditions of temperature and time. Equilibrium conditions have been established and its relationship with temperature has bee...Oxygen isotope fractionation is studied during the synthesis of kaolinite under controlled conditions of temperature and time. Equilibrium conditions have been established and its relationship with temperature has been studied. Kaolinite was hydrothermally precipitated starting from non-crystalline aluminosilicate gels. The amount of kaolinite obtained increases up to a limited constant value and in all cases coexists with the amorphous starting gels. It can be seen that the data obtained at 48 hours of synthesis can be considered as quasi-equilibrium, since the total isotopic equilibrium has not been reached, only the sample obtained at 24 hours should be discarded for studies in equilibrium. This would allow us, with the samples obtained at 720 hours, to try to establish a relationship between isotopic fractionation and temperature, provided that we know the water in equilibrium with the synthesized kaolinite. Two equations have been obtained that show correlation coefficients with a high statistical significance.展开更多
The effect of thermal oxidation of activated carbon surface on its adsorption of dibenzothiophene was investigated.The surface oxidation of the activated carbon was carried out by heating at different temperatures in ...The effect of thermal oxidation of activated carbon surface on its adsorption of dibenzothiophene was investigated.The surface oxidation of the activated carbon was carried out by heating at different temperatures in the air.Static equilibrium adsorption experiments were conducted to determine the isotherms of dibenzothiophene on the original and oxidized activated carbons.The type and concentration of oxygen functional groups on the activated carbons were determined by diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and Boehm titration respectively.The influence of the surface chemistry of the activated carbons on the adsorption capacity for dibenzothiophene was discussed.The results showed that the acid oxygen-containing groups of the activated carbon surfaces played an important role in enhancing the adsorption of dibenzothiophene.It was shown that the use of thermal oxidation could increase the concentration of oxygen-containing groups on the activated carbon surfaces,and consequently increase its adsorption capacity for dibenzothiophene.It was also found that the higher the oxidation temperature,the more the oxygen-containing groups on activated carbon surface,which enhanced the adsorption capacity of dibenzothiophene on its surfaces.The Langmuir equation was shown to fit well these isotherms.展开更多
基金the financial support from the Recruitment Program of Global Experts(Thousand Talents),Chinathe Natural Science Foundation of China(41322015)
文摘Oxygen isotope fractionation between coexisting minerals in slowly cooled rocks conveys information about their cooling history. By using the fast grain boundary(FGB) model to simulate closed-system diffusive exchange of oxygen isotopes between coexisting minerals, I show that the apparent equilibrium temperatures(Tae) by the mineral pair with the largest isotopic fractionation(PLIF) always lies between the closure temperatures(Tc) of those two minerals. Therefore, when the rate of oxygen diffusion and hence Tc for the PLIF chance to be comparable(such as in the case of quartz and magnetite), Tae will serve as a good approximation of Tc regardless of variation in mineral proportions. The specialty of the PLIF in constraining Tae within their Tc range can be generalized to other stable isotope systems and element partitioning. By approximating Tc with Tae and inverting Dodson's equation, the cooling rate of plutonic or metamorphic rocks can be inferred.
文摘Ironmaking is the art of removal the arch-enemy oxygen from iron ore by means of carbon reduction and thus producing hot metal.Steelmaking is the art of removing carbon from liquid hot metal by means of best friend pure oxygen,followed by alloying and deoxidation-where oxygen returns to be the arch-enemy.Non-metallic particles in steel such as oxides can have a detrimental effect on the steel product properties in terms of formability,strength and surface properties.An overview of the battle for clean steel production is given based on the experience of the author in industry as well as university research.
基金gratefully express their appreciation to National Natural Science Foundation of China(Nos.51974153 and U1960203)the Joint Fund of State Key Laboratory of Marine Engineering and University of Science and Technology Liaoning(SKLMEA-USTL-201707)the China Scholarship Council(201908210457).
文摘The interfacial oxygen transfer rate is one of the main factors to control the composition of alloys.The commonly employed method of studying the interfacial oxygen transfer rate is the chemical composition analysis;however,it is difficult to be studied in situ.Here,a new method of measuring the oxygen transfer rate at the gas-slag and slag-metal interfaces was reported based on electrochemical analyses.The interfacial oxygen transfer rate in the smelting process of Inconel 718 superalloy was investigated at 1723,1773,1823,and 1873 K.The experimental results show that the electrochemical method can measure the real-time oxygen content;hence,this method is promising in controlling the oxygen content in alloys.As the temperature increased,both the equilibrium oxygen content and the rate of oxygen absorption increased significantly,and the increase was the most obvious when the temperature was 1873 K.The possible reason is that the increase in temperature weakens the mass transfer resistance of the electric double layer at the interface,thus accelerating the oxygen transfer rate.
基金the National Science Foundation of China(Nos.50934001 and 51322402)the National High-Tech Research and Development Program of China (No.2012AA062302)+2 种基金the Program of the Co-construction with Beijing Municipal Commission of Education of China (Nos.00012047 and 00012085)the Program for New Century Excellent Talents in Universities(NCET-11-0577)the Fundamental Research Funds for the Central Universities(No.FRF-AS-11-003A)
文摘TiClx （x=2.17） was prepared by using titanium sponge to reduce the concentration of TiCl4 in a NaCl-KCl melt under negative pressure. The as-prepared NaCl-KCl-TiClx melt was employed as the electrolyte, and two parallel crude titanium plates and one high-purity titanium plate were used as the anode and cathode, respectively. A series of electrochemical tests were performed to investigate the influence of electrolytic parameters on the current efficiency and quality of cathodic products. The results indicated that the quality of cathodic products was related to the current efficiency, which is significantly dependent on the current density and the initial concentration of titanium ions. The significance of this study is the attainment of high-purity titanium with a low oxygen content of 30× 10^-6.
基金Item Sponsored by National Natural Science Foundation of China(50974034,51074039)
文摘A high temperature equilibration experiment was carried out to investigate the effect of oxygen partial pres- sure on the phase equilibria and liquidus in CaO-Al2O3- FeOx system with the intermediate oxygen partial pressures of 10.13 Pa and 1.01 × 10^-3 Pa. The equilibrated phases and their compositions of the quenched samples were analyzed by using SEM/EPMA （Scanning Electron Microscope/Electron Probe Micro Analysis） and XRD （X Ray Diffraction）. The phase equilibrium results include two cases, the two phase coexistence and the three-phase coexistence in the high Al2O3 region with oxygen partial pressure of either 10.13 Pa or 1.01 × 10^-3 Pa. Effects of oxygen partial pressure and temperature on the liquidus along the primary phase fields of CaO · Al2O3 and CaO · 2Al2O3 were nota hle. With the decrease of oxygen partial pressure, the liquid area expands and the liquidus of CaO · Al2O3 and CaO · 2Al2O3 primary fields moves to the Al2O3-FeOx region. On the other hand, the liquid area of CaO Al2O3-FeOx sys tem extends extremely to the high Al2O3 region with the temperature increasing from 1 400 to 1 500℃, especially at lower oxygen partial pressure. The present experiment results are in good agreement with the calculated ones by FactSage.
文摘Thimble zirconia oxygen sensors were prepared with yttria stabilized zirconia(YSZ). The surfaces of the electrode, electrolyte and their interface were observed by scanning electron microscope(SEM). The sensor was examined with engine bench test to evaluate the essential performance. The results show that the oxygen sensor has good performance, which can meet the demand of practical applications. Chemical equilibrium theory was introduced to explain electromotive force of the sensors and the influence of temperature on the signals. The educed theoretical model of electromotive force agrees well with testing results.
文摘Oxygen isotope fractionation is studied during the synthesis of kaolinite under controlled conditions of temperature and time. Equilibrium conditions have been established and its relationship with temperature has been studied. Kaolinite was hydrothermally precipitated starting from non-crystalline aluminosilicate gels. The amount of kaolinite obtained increases up to a limited constant value and in all cases coexists with the amorphous starting gels. It can be seen that the data obtained at 48 hours of synthesis can be considered as quasi-equilibrium, since the total isotopic equilibrium has not been reached, only the sample obtained at 24 hours should be discarded for studies in equilibrium. This would allow us, with the samples obtained at 720 hours, to try to establish a relationship between isotopic fractionation and temperature, provided that we know the water in equilibrium with the synthesized kaolinite. Two equations have been obtained that show correlation coefficients with a high statistical significance.
文摘The effect of thermal oxidation of activated carbon surface on its adsorption of dibenzothiophene was investigated.The surface oxidation of the activated carbon was carried out by heating at different temperatures in the air.Static equilibrium adsorption experiments were conducted to determine the isotherms of dibenzothiophene on the original and oxidized activated carbons.The type and concentration of oxygen functional groups on the activated carbons were determined by diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and Boehm titration respectively.The influence of the surface chemistry of the activated carbons on the adsorption capacity for dibenzothiophene was discussed.The results showed that the acid oxygen-containing groups of the activated carbon surfaces played an important role in enhancing the adsorption of dibenzothiophene.It was shown that the use of thermal oxidation could increase the concentration of oxygen-containing groups on the activated carbon surfaces,and consequently increase its adsorption capacity for dibenzothiophene.It was also found that the higher the oxidation temperature,the more the oxygen-containing groups on activated carbon surface,which enhanced the adsorption capacity of dibenzothiophene on its surfaces.The Langmuir equation was shown to fit well these isotherms.
