The potential—pH diagrams of the Cr-H2O system at temperatures of 298, 323, 373 and 423 K were established through thermodynamic calculation with coupling of experimental results. The potential—pH diagram at 298 K a...The potential—pH diagrams of the Cr-H2O system at temperatures of 298, 323, 373 and 423 K were established through thermodynamic calculation with coupling of experimental results. The potential—pH diagram at 298 K agrees well with the previously reported results. Based on the potential—pH diagrams of the Cr-H2O and Fe-H2O systems, IR spectra and XRD pattern, the existence forms of iron in the potassium chromate were analyzed, and the methods of iron removal were investigated. The results show that the existence forms of iron in the potassium chromate are potassium ferrate. These results are instructive and helpful to the hydrometallurgical processing of chromite ore.展开更多
The principles of chemical equilibrium were used to derive a new set of formulae representing the oxygen potentials for five buffer gas mixtures at normal pressure.Various sorts of classical formulae for them are on- ...The principles of chemical equilibrium were used to derive a new set of formulae representing the oxygen potentials for five buffer gas mixtures at normal pressure.Various sorts of classical formulae for them are on- ly a particular representation under ignoring the effects of oxygen,thereby being unavailable for accurate cal- culation of oxygen potentials.In this paper,the oxygen potentials set by CO_2-H_2 gas mixtures and the mis- takes and errors of the classical expressions for them were discussed emphatically.The deviation in partial pressures of oxygen in some of previous experiments under the oxygen potentials controlled by CO_2-H_2 gas mixtures was explained quantitatively.The oxygen-potential diagrams predicting the equilibrated gas com- positions from the initial conditions have been also given.展开更多
The ruminal redox potential (Eh) can reflect the microbiological activity and dynamics of fermentation in the rumen. It might be an important indicator of rumen fermentation in combination with pH. However, the rumina...The ruminal redox potential (Eh) can reflect the microbiological activity and dynamics of fermentation in the rumen. It might be an important indicator of rumen fermentation in combination with pH. However, the ruminal Eh has been rarely studied in dairy cows due to the difficulty of its measurement, and the relationship between ruminal Eh and pH is not clear. The objective of this study was to investigate the relationship between ruminal Eh and pH of dairy cows by meta-analysis of systematic measurements from different experiments. A database was constructed from 22 experiments on cannulated dairy cattle including 57 dietary treatments. The ruminal pH and Eh were measured without air contact between 0 and 8 h post-feeding. The results demonstrated a quadratic correlation between ruminal Eh and pH with a reliable within-animal variation (Eh = -1697 + 540.7 pH -47.7 pH2, nobservation = 70, nanimal = 26, P Eh, but not always to the same extent. Some of them still influenced the relationship between ruminal Eh and pH. While the mechanism of the interaction between ruminal Eh and pH remains to be elucidated, it would be interesting to associate Eh to microbial profile, ruminal VFA concentration and milk production performance in future studies.展开更多
The continuous rise of consumer price index (CPI) has increased concern over China's macroeconomic situation. Will inflation have a disastrous impact on the Chinese economy? What risks are brewing behind the boomi...The continuous rise of consumer price index (CPI) has increased concern over China's macroeconomic situation. Will inflation have a disastrous impact on the Chinese economy? What risks are brewing behind the booming real estate and stock markets? Have bubbles already occurred in the Chinese economy? From his office in Guohong Building, Beijing, Dr. Fan Gang gave his views on these questions in an exclusive interview with China Economist.展开更多
The effects of marine environmental factors-temperature （T）, dissolved oxygen （DO）, salinity （S） and pH--on the oxidation-reduction potential （ORP） of natural seawater were studied in laboratory. The results s...The effects of marine environmental factors-temperature （T）, dissolved oxygen （DO）, salinity （S） and pH--on the oxidation-reduction potential （ORP） of natural seawater were studied in laboratory. The results show an indistinct relationship between these four factors and the ORE but they did impact the ORP. Common mathematical methods were not applicable for describing the relationship. Therefore, a grey relational analysis （GRA） method was developed. The degrees of correlation were calculated according to GILA and the values of T, pH, DO and S were 0.744, 0.710, 0.692 and 0.690, respectively. From these values, the relations of these factors to the ORP could be described and evaluated, and those of T and pH were relatively major. In general, ORP is influenced by the synergic effect of T, DO, pH and S, with no single factor having an outstanding role.展开更多
From the Gibbs free energy and the equations of two-phase equilibrium curves of the two-dimensionalbinary system which has the Lennard-Jones potential, using the Collins model, the eutectic-type phase diagram and thep...From the Gibbs free energy and the equations of two-phase equilibrium curves of the two-dimensionalbinary system which has the Lennard-Jones potential, using the Collins model, the eutectic-type phase diagram and theperitectic-type phase diagram of the binary system are obtained, whose results are quite similar to the behavior of thethree-dimensional (3D) substances.展开更多
For aqueous interfacial reactions involving H+and OH-, the interfacial pH varies dynamically during the reaction process, which is a key factor determining the reaction performance. Herein, the kinetic relevance betwe...For aqueous interfacial reactions involving H+and OH-, the interfacial pH varies dynamically during the reaction process, which is a key factor determining the reaction performance. Herein, the kinetic relevance between the interfacial pH and reaction rate is deciphered owing to the success in establishing the transport equations of H+/OH- in unbuffered solutions, and is charted as a current(j)–pH diagram in the form of an electrochemical response. The as-described j–pH interplay is experimentally verified by the oxygen reduction and hydrogen evolution reactions. This diagram serves to form a panoramic graphic view of pH function working on the interfacial reactions in conjunction with the Pourbaix’s potential–pH diagram, and particularly enables a kinetic understanding of the transport effect of H+and OH-on the reaction rate and valuable instruction toward associated pH control and buffering manipulation.展开更多
This study investigated the leaching potential of diuron and linuron in different soil types in Gaza Strip, Palestine under laboratory and field conditions. Leaching potential was evaluated by tin columns and bioassay...This study investigated the leaching potential of diuron and linuron in different soil types in Gaza Strip, Palestine under laboratory and field conditions. Leaching potential was evaluated by tin columns and bioassay technique using Molokhia as test plant. The responses of the test plant were regressed versus concentrations of the herbicide to estimate linear regression equation and the regression coefficient. The obtained results indicate strong positive association between Molokhia and concentrations of diuron or linuron;accordingly it was used in the bioassay and estimation of the concentrations of the tested herbicides in the leaching depth. Leaching potential was very low in North Gaza and Kkan Younis soil, whereas in the Meddle zone soil was very large. Leaching potential under laboratory conditions was larger that under field conditions. The bioestimated concentrations in soil layer under field conditions were sever folds of magnitude lower than those under laboratory conditions. The interesting outcome of this study is that leaching potential is dependent on soil clay fraction, soil organic matter, and soil pH. These results provided answers to the questions raised by farmers in Gaza Strip.展开更多
The Collins model is introduced into the two-dimensional (2D) alternative ternary system having the Lennard-Jones (L-J) potential. The Gibbs free energy of this ternary system is calculated, and according to thermodyn...The Collins model is introduced into the two-dimensional (2D) alternative ternary system having the Lennard-Jones (L-J) potential. The Gibbs free energy of this ternary system is calculated, and according to thermodynamic theory, a group of equations that determine the solid-liquid diagram of ternary system are derived, someisothermal sectional diagrams of the 2D ternary system are obtained. The results are quite similar to the behavior ofthree-dimensional substances.展开更多
We investigate the nonlinear modes in a rotating double well potential with 79T symmetry. Focus on the existence and stability of the nonlinear PT modes in this system, we found that five types of PT modes can stably ...We investigate the nonlinear modes in a rotating double well potential with 79T symmetry. Focus on the existence and stability of the nonlinear PT modes in this system, we found that five types of PT modes can stably exist by given certain parameter settings. The multistable area between these modes are studied numerically and the bistable and tristable areas are delimited. With different input trial wavefunctions, five types of solitary wave modes are identified. We found that the rotating of the potential can significantly affect the power flow of the fundamental harmonic mode, whose effect is absent for the other modes.展开更多
Aqueous E pH Diagram is an essential tool for analyzing hydrometallurgical and corrosion processes. Due to the requirements for environmental protection and energy saving in recent years, waste water processing a...Aqueous E pH Diagram is an essential tool for analyzing hydrometallurgical and corrosion processes. Due to the requirements for environmental protection and energy saving in recent years, waste water processing and hydrometallurgical process of concentrate have been greatly developed. The construction of E pH diagrams has turned to multi component systems. However, there are some limits in plotting such diagrams. There is only one diagram for one multi component system, which can not reflect the truth of the aqueous reaction. In the paper, a new computation method is proposed to construct E pH diagrams. Component activity term is used to determine the boundary of stable areas. For the multi component systems, different atom ratios of elements have been taken into account. M S H 2O system is chosen to study since it is of importance in metallurgical solution. Compared with conventional methods, the algorithm is simple and conforms to real conditions.展开更多
Rare earth elements are indispensable raw materials for advanced aero-engines, special optical materials, and high-performance electronic products. With the development of the social economy, the global demand for rar...Rare earth elements are indispensable raw materials for advanced aero-engines, special optical materials, and high-performance electronic products. With the development of the social economy, the global demand for rare earth resources is increasing, and rare earths have become a key metal for the development of new industries and frontier technologies that are highly valued both at home and abroad. Ion-adsorbed rare earth ores are an important source of rare earths, so the efficient green leaching of ion-adsorbed rare earths is important. Researchers found that the selection of an efficient green leaching agent for ion-adsorbed rare earths is based on the zeta potential of tailing clay minerals in addition to leaching efficiency, and both zeta potential and leaching ion concentration are related to mineral acidity and alkalinity, and the pH of tailing water suspension is a direct indicator of environmental water quality requirements. Therefore, the efficiency of the leaching process is closely integrated with the environmental evaluation, and the characteristics and correlation of the changes in zeta potential, pH, conductivity and pollutant concentration of the pulp of clay mineral content during the leaching process of ore leaching and tailings aqueous electrolyte solution leaching are studied by evaluating the leaching system, and a set of correlation leaching efficiency and environmental impact evaluation method is established based on the results of the above analysis, which is of scientific development of ion adsorption rare earth resources. It has important theoretical significance and practical application value.展开更多
The effect of brine salinity,cation type,pH,and produced sand on zeta potential(ZP)measurements with and without the presence of silica nanoparticles is investigated through pH measurement,static tests for sand and ZP...The effect of brine salinity,cation type,pH,and produced sand on zeta potential(ZP)measurements with and without the presence of silica nanoparticles is investigated through pH measurement,static tests for sand and ZP measurements as well as Field Emission Scanning Electron Microscope(FESEM)analyses.Three important factors were investigated:composition of the injected brine,surface charge and pH.Their influence on stability of nanoparticles in the injected brine and amount of sand segregation was determined and the analysis of the new outcomes based on rock/brine ZP measurements was reported.The results show that the use of silica nanoparticles with high pH helps in preventing sand production and that pH has a main effect on the surface charge of the sand particle released,affecting the ZP of the solution.Nanoparticles can be active as a coating on sand grains and prevent sand segregation during water flooding.Divalent cations have been found to acquire a more substantial impact on neutralizing the negative charge of the sand particles than monovalent cations at the same concentration and pH conditions at 25℃.The value of ZP becomes of higher negative value with the decrease of brine salinity.The effectiveness of SiO_(2)nanoparticles is quite different for soft water and smart water.For soft water,the nanoparticles work more effective at pH higher than 8;and for smart water,the nanoparticles perform better at pH lower than 8.To reduce sand production with the use of silica nanoparticles,it is highly suggested to increase pH,as pH and sand production mechanisms were observed to be inversely related.展开更多
基金Project(2007CB613501) supported by the National Basic Research Program of ChinaProject(2006BAC02A05) supported by the National Science and Technology Pillar Program of ChinaProject(50904058) supported by the National Natural Science Foundation of China
文摘The potential—pH diagrams of the Cr-H2O system at temperatures of 298, 323, 373 and 423 K were established through thermodynamic calculation with coupling of experimental results. The potential—pH diagram at 298 K agrees well with the previously reported results. Based on the potential—pH diagrams of the Cr-H2O and Fe-H2O systems, IR spectra and XRD pattern, the existence forms of iron in the potassium chromate were analyzed, and the methods of iron removal were investigated. The results show that the existence forms of iron in the potassium chromate are potassium ferrate. These results are instructive and helpful to the hydrometallurgical processing of chromite ore.
文摘The principles of chemical equilibrium were used to derive a new set of formulae representing the oxygen potentials for five buffer gas mixtures at normal pressure.Various sorts of classical formulae for them are on- ly a particular representation under ignoring the effects of oxygen,thereby being unavailable for accurate cal- culation of oxygen potentials.In this paper,the oxygen potentials set by CO_2-H_2 gas mixtures and the mis- takes and errors of the classical expressions for them were discussed emphatically.The deviation in partial pressures of oxygen in some of previous experiments under the oxygen potentials controlled by CO_2-H_2 gas mixtures was explained quantitatively.The oxygen-potential diagrams predicting the equilibrated gas com- positions from the initial conditions have been also given.
文摘The ruminal redox potential (Eh) can reflect the microbiological activity and dynamics of fermentation in the rumen. It might be an important indicator of rumen fermentation in combination with pH. However, the ruminal Eh has been rarely studied in dairy cows due to the difficulty of its measurement, and the relationship between ruminal Eh and pH is not clear. The objective of this study was to investigate the relationship between ruminal Eh and pH of dairy cows by meta-analysis of systematic measurements from different experiments. A database was constructed from 22 experiments on cannulated dairy cattle including 57 dietary treatments. The ruminal pH and Eh were measured without air contact between 0 and 8 h post-feeding. The results demonstrated a quadratic correlation between ruminal Eh and pH with a reliable within-animal variation (Eh = -1697 + 540.7 pH -47.7 pH2, nobservation = 70, nanimal = 26, P Eh, but not always to the same extent. Some of them still influenced the relationship between ruminal Eh and pH. While the mechanism of the interaction between ruminal Eh and pH remains to be elucidated, it would be interesting to associate Eh to microbial profile, ruminal VFA concentration and milk production performance in future studies.
文摘The continuous rise of consumer price index (CPI) has increased concern over China's macroeconomic situation. Will inflation have a disastrous impact on the Chinese economy? What risks are brewing behind the booming real estate and stock markets? Have bubbles already occurred in the Chinese economy? From his office in Guohong Building, Beijing, Dr. Fan Gang gave his views on these questions in an exclusive interview with China Economist.
基金Supporte by the Knowledge Innovation Project of the Chinese Academy of Sciences (No KZCX2-YW-210)National Key Technology Research and Development Program (No2007BAB27B04)the High Technology Research and Development Program of China (No 2001AA635080)
文摘The effects of marine environmental factors-temperature （T）, dissolved oxygen （DO）, salinity （S） and pH--on the oxidation-reduction potential （ORP） of natural seawater were studied in laboratory. The results show an indistinct relationship between these four factors and the ORE but they did impact the ORP. Common mathematical methods were not applicable for describing the relationship. Therefore, a grey relational analysis （GRA） method was developed. The degrees of correlation were calculated according to GILA and the values of T, pH, DO and S were 0.744, 0.710, 0.692 and 0.690, respectively. From these values, the relations of these factors to the ORP could be described and evaluated, and those of T and pH were relatively major. In general, ORP is influenced by the synergic effect of T, DO, pH and S, with no single factor having an outstanding role.
文摘From the Gibbs free energy and the equations of two-phase equilibrium curves of the two-dimensionalbinary system which has the Lennard-Jones potential, using the Collins model, the eutectic-type phase diagram and theperitectic-type phase diagram of the binary system are obtained, whose results are quite similar to the behavior of thethree-dimensional (3D) substances.
基金the National Natural Science Foundation of China(51525805,51727812,51808526)。
文摘For aqueous interfacial reactions involving H+and OH-, the interfacial pH varies dynamically during the reaction process, which is a key factor determining the reaction performance. Herein, the kinetic relevance between the interfacial pH and reaction rate is deciphered owing to the success in establishing the transport equations of H+/OH- in unbuffered solutions, and is charted as a current(j)–pH diagram in the form of an electrochemical response. The as-described j–pH interplay is experimentally verified by the oxygen reduction and hydrogen evolution reactions. This diagram serves to form a panoramic graphic view of pH function working on the interfacial reactions in conjunction with the Pourbaix’s potential–pH diagram, and particularly enables a kinetic understanding of the transport effect of H+and OH-on the reaction rate and valuable instruction toward associated pH control and buffering manipulation.
文摘This study investigated the leaching potential of diuron and linuron in different soil types in Gaza Strip, Palestine under laboratory and field conditions. Leaching potential was evaluated by tin columns and bioassay technique using Molokhia as test plant. The responses of the test plant were regressed versus concentrations of the herbicide to estimate linear regression equation and the regression coefficient. The obtained results indicate strong positive association between Molokhia and concentrations of diuron or linuron;accordingly it was used in the bioassay and estimation of the concentrations of the tested herbicides in the leaching depth. Leaching potential was very low in North Gaza and Kkan Younis soil, whereas in the Meddle zone soil was very large. Leaching potential under laboratory conditions was larger that under field conditions. The bioestimated concentrations in soil layer under field conditions were sever folds of magnitude lower than those under laboratory conditions. The interesting outcome of this study is that leaching potential is dependent on soil clay fraction, soil organic matter, and soil pH. These results provided answers to the questions raised by farmers in Gaza Strip.
基金The project supported by National Natural Science Foundation of China
文摘The Collins model is introduced into the two-dimensional (2D) alternative ternary system having the Lennard-Jones (L-J) potential. The Gibbs free energy of this ternary system is calculated, and according to thermodynamic theory, a group of equations that determine the solid-liquid diagram of ternary system are derived, someisothermal sectional diagrams of the 2D ternary system are obtained. The results are quite similar to the behavior ofthree-dimensional substances.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11104083 and 10934011)
文摘We investigate the nonlinear modes in a rotating double well potential with 79T symmetry. Focus on the existence and stability of the nonlinear PT modes in this system, we found that five types of PT modes can stably exist by given certain parameter settings. The multistable area between these modes are studied numerically and the bistable and tristable areas are delimited. With different input trial wavefunctions, five types of solitary wave modes are identified. We found that the rotating of the potential can significantly affect the power flow of the fundamental harmonic mode, whose effect is absent for the other modes.
文摘Aqueous E pH Diagram is an essential tool for analyzing hydrometallurgical and corrosion processes. Due to the requirements for environmental protection and energy saving in recent years, waste water processing and hydrometallurgical process of concentrate have been greatly developed. The construction of E pH diagrams has turned to multi component systems. However, there are some limits in plotting such diagrams. There is only one diagram for one multi component system, which can not reflect the truth of the aqueous reaction. In the paper, a new computation method is proposed to construct E pH diagrams. Component activity term is used to determine the boundary of stable areas. For the multi component systems, different atom ratios of elements have been taken into account. M S H 2O system is chosen to study since it is of importance in metallurgical solution. Compared with conventional methods, the algorithm is simple and conforms to real conditions.
文摘Rare earth elements are indispensable raw materials for advanced aero-engines, special optical materials, and high-performance electronic products. With the development of the social economy, the global demand for rare earth resources is increasing, and rare earths have become a key metal for the development of new industries and frontier technologies that are highly valued both at home and abroad. Ion-adsorbed rare earth ores are an important source of rare earths, so the efficient green leaching of ion-adsorbed rare earths is important. Researchers found that the selection of an efficient green leaching agent for ion-adsorbed rare earths is based on the zeta potential of tailing clay minerals in addition to leaching efficiency, and both zeta potential and leaching ion concentration are related to mineral acidity and alkalinity, and the pH of tailing water suspension is a direct indicator of environmental water quality requirements. Therefore, the efficiency of the leaching process is closely integrated with the environmental evaluation, and the characteristics and correlation of the changes in zeta potential, pH, conductivity and pollutant concentration of the pulp of clay mineral content during the leaching process of ore leaching and tailings aqueous electrolyte solution leaching are studied by evaluating the leaching system, and a set of correlation leaching efficiency and environmental impact evaluation method is established based on the results of the above analysis, which is of scientific development of ion adsorption rare earth resources. It has important theoretical significance and practical application value.
文摘The effect of brine salinity,cation type,pH,and produced sand on zeta potential(ZP)measurements with and without the presence of silica nanoparticles is investigated through pH measurement,static tests for sand and ZP measurements as well as Field Emission Scanning Electron Microscope(FESEM)analyses.Three important factors were investigated:composition of the injected brine,surface charge and pH.Their influence on stability of nanoparticles in the injected brine and amount of sand segregation was determined and the analysis of the new outcomes based on rock/brine ZP measurements was reported.The results show that the use of silica nanoparticles with high pH helps in preventing sand production and that pH has a main effect on the surface charge of the sand particle released,affecting the ZP of the solution.Nanoparticles can be active as a coating on sand grains and prevent sand segregation during water flooding.Divalent cations have been found to acquire a more substantial impact on neutralizing the negative charge of the sand particles than monovalent cations at the same concentration and pH conditions at 25℃.The value of ZP becomes of higher negative value with the decrease of brine salinity.The effectiveness of SiO_(2)nanoparticles is quite different for soft water and smart water.For soft water,the nanoparticles work more effective at pH higher than 8;and for smart water,the nanoparticles perform better at pH lower than 8.To reduce sand production with the use of silica nanoparticles,it is highly suggested to increase pH,as pH and sand production mechanisms were observed to be inversely related.
