1 Introduction Physical and numerical models are constructed to investigate the evolution and mechanism of salt migration driven by tectonic processes.In recent years,we have designed and ran series of models to simul...1 Introduction Physical and numerical models are constructed to investigate the evolution and mechanism of salt migration driven by tectonic processes.In recent years,we have designed and ran series of models to simulate salt展开更多
1 Introduction It has been noticed that salts link the Earth’s spheres(Zheng,2007),and rich information must have been recorded by salts on the geological processes they involved in.Salts have been found on Mars,Euro...1 Introduction It has been noticed that salts link the Earth’s spheres(Zheng,2007),and rich information must have been recorded by salts on the geological processes they involved in.Salts have been found on Mars,Europa,Enceladus,and salts might be common on planets(Zheng et al.,2013).Thus salts can be potential indicators for studying the geological history of planets.From the beginning of the 21st century,much new展开更多
Various material design strategies have been developed to enhance photocatalytic performance of TiO_(2).However,no report is available on applications of the photopiezocatalysis strategy on TiO_(2)due to its lack of p...Various material design strategies have been developed to enhance photocatalytic performance of TiO_(2).However,no report is available on applications of the photopiezocatalysis strategy on TiO_(2)due to its lack of piezoelectricity.Here we developed a low-temperature molten salt etching process to create rutile TiO_(2)nanoparticles by etching[MgO_(6)]octahedrons away from MgTiO_(3)by molten NH_(4)Cl,during which a lattice distortion occurred in TiO_(2).The lattice distortion broke the structure symmetry of rutile TiO_(2)and subsequently endowed these rutile TiO_(2)nanoparticles with an unusual piezoelectric response with the maximum effective piezoelectric coefficient(d_(33))of~41.6 pm/V,which had not previously been found in TiO_(2)photocatalysts.Thus,the photopiezocatalysis strategy was applied for the first time to enhance the photocatalytic performance of these TiO_(2)nanoparticles.The creation of lattice distortion to induce piezoelectricity could be extended to other photocatalysts that the photopiezocatalysis strategy has not been applied to and may generate novel functionalities for various technical applications.展开更多
Al-Cu-Y alloys were prepared by molten salt electrolysis in fluoride-oxide system composed of electrolyte（Na3 AlF6-AlF3-LiF-MgF2） and oxide（Al2 O3-CuO-Y2 O3）. Cathodic reduction process of Al2 O3,CuO and Y2 O3 wer...Al-Cu-Y alloys were prepared by molten salt electrolysis in fluoride-oxide system composed of electrolyte（Na3 AlF6-AlF3-LiF-MgF2） and oxide（Al2 O3-CuO-Y2 O3）. Cathodic reduction process of Al2 O3,CuO and Y2 O3 were analyzed by cyclic voltammetry and chronoamperometry. Components and phase composition of alloy samples prepared by potentiostatic electrolysis were characterized by scanning electron microscopy and energy dispersive spectroscopy. The results show that the Al-Cu-Y alloy can be prepared in the AIF3-NaF-5 wt%LiF-5 wt%MgF2（NaF/AlF3 = 2.2, molecular ratio） eutectic system with mixed oxide（Al2 O3-CuO-Y2 O3） through 2 h at the conditions of a temperature of 1208 K, cell voltage3.0 V, cathode current density 0.7 A/cm^2. Al（Ⅲ） and Cu（Ⅱ） ions can be reduced to zero valence Al（0） and Cu（0） directly on carbonaceous electrode surface by instantaneous nucleation, respectively, the reduction process is controlled by diffusion. The reduction potential of Y（Ⅲ） ions is close to the active ions of fluoride melts, but strengthened phase AI3 Y can be formed through electrochemical reduction and alloyed process with active Al（Ⅲ） and Cu（Ⅱ） ions, meanwhile, the Al2 Cu and Al3 Y phases are distributed at the grain boundary of Al matrix.展开更多
The simultaneous control of crystal phase stability and one-dimensional growth has always been the major challenge for the preparation of tetragonal zirconia whiskers.In this study,we report a facile molten salt proce...The simultaneous control of crystal phase stability and one-dimensional growth has always been the major challenge for the preparation of tetragonal zirconia whiskers.In this study,we report a facile molten salt processing that utilizes CaF_(2) as a stabilizer and adsorbent to meet the phase and morphology requirements.The processes of stabilization,phase transition,ion adsorption and formation of special morphology involved in zirconia growth were investigated by XRD,IR,SEM,DTA-TG and TEM.By controlling the amount of CaF_(2)(15 wt%)added in the reaction precursor,tetragonal zirconia whiskers with a desired aspect ratio(>16)can be synthesized,which show single crystalline nature and[001]preferred direction.Ca ions doped at low temperature inhibit the occurrence of phase transition,which allows the tetragonal structure to be retained to room temperature.The inducement and pattern of whisker growth are supposed to be F-adsorption and screw dislocation elongation,respectively.The specific selectivity of surface adsorbed ions to certain zirconia crystal planes reduces or even inhibits the epitaxial growth rate in this direction,offering a viable avenue for the morphology modulation of inorganic nanomaterials.展开更多
基金supported by China Geological Survey Bureau potash resources investigation and evaluation project (1212011085524)NSFC projects (40872134, 41272227 )
文摘1 Introduction Physical and numerical models are constructed to investigate the evolution and mechanism of salt migration driven by tectonic processes.In recent years,we have designed and ran series of models to simulate salt
文摘1 Introduction It has been noticed that salts link the Earth’s spheres(Zheng,2007),and rich information must have been recorded by salts on the geological processes they involved in.Salts have been found on Mars,Europa,Enceladus,and salts might be common on planets(Zheng et al.,2013).Thus salts can be potential indicators for studying the geological history of planets.From the beginning of the 21st century,much new
基金This study was supported by the National Natural Science Foundation of China(Grant Nos.52272125 and 51902271)the Fundamental Research Funds for the Central Universities(Grant Nos.2682021CX116,2682020CX07,and 2682020CX08)Sichuan Science and Technology Program(Grant Nos.2020YJ0259,2020YJ0072,and 2021YFH0163).We would like to thank Analysis and Testing Center of Southwest Jiaotong University for the assistance on material characterization.
文摘Various material design strategies have been developed to enhance photocatalytic performance of TiO_(2).However,no report is available on applications of the photopiezocatalysis strategy on TiO_(2)due to its lack of piezoelectricity.Here we developed a low-temperature molten salt etching process to create rutile TiO_(2)nanoparticles by etching[MgO_(6)]octahedrons away from MgTiO_(3)by molten NH_(4)Cl,during which a lattice distortion occurred in TiO_(2).The lattice distortion broke the structure symmetry of rutile TiO_(2)and subsequently endowed these rutile TiO_(2)nanoparticles with an unusual piezoelectric response with the maximum effective piezoelectric coefficient(d_(33))of~41.6 pm/V,which had not previously been found in TiO_(2)photocatalysts.Thus,the photopiezocatalysis strategy was applied for the first time to enhance the photocatalytic performance of these TiO_(2)nanoparticles.The creation of lattice distortion to induce piezoelectricity could be extended to other photocatalysts that the photopiezocatalysis strategy has not been applied to and may generate novel functionalities for various technical applications.
基金Project supported by the National Natural Science Foundation of China(51564015)
文摘Al-Cu-Y alloys were prepared by molten salt electrolysis in fluoride-oxide system composed of electrolyte（Na3 AlF6-AlF3-LiF-MgF2） and oxide（Al2 O3-CuO-Y2 O3）. Cathodic reduction process of Al2 O3,CuO and Y2 O3 were analyzed by cyclic voltammetry and chronoamperometry. Components and phase composition of alloy samples prepared by potentiostatic electrolysis were characterized by scanning electron microscopy and energy dispersive spectroscopy. The results show that the Al-Cu-Y alloy can be prepared in the AIF3-NaF-5 wt%LiF-5 wt%MgF2（NaF/AlF3 = 2.2, molecular ratio） eutectic system with mixed oxide（Al2 O3-CuO-Y2 O3） through 2 h at the conditions of a temperature of 1208 K, cell voltage3.0 V, cathode current density 0.7 A/cm^2. Al（Ⅲ） and Cu（Ⅱ） ions can be reduced to zero valence Al（0） and Cu（0） directly on carbonaceous electrode surface by instantaneous nucleation, respectively, the reduction process is controlled by diffusion. The reduction potential of Y（Ⅲ） ions is close to the active ions of fluoride melts, but strengthened phase AI3 Y can be formed through electrochemical reduction and alloyed process with active Al（Ⅲ） and Cu（Ⅱ） ions, meanwhile, the Al2 Cu and Al3 Y phases are distributed at the grain boundary of Al matrix.
基金supported by the National Natural Science Foundation of China[grant numbers 51662016,51962014,52072162]the Key Research and Development Program of Jiangxi Province,China[grant number 20192BBEL50022]+3 种基金the Key projects of Youth Fund of Jiangxi Province,China[grant number 20202ACBL214006,20202ACBL214008]the Key Science Foundation of Jiangxi Provincial Department of Education,China[grant number GJJ180699]the Scientific Research Fund of Jiangxi Provincial Education Department(grant number GJJ160881)the Youth Science Foundation of Jiangxi Provincia Department of Education,China[grant number GJJ180740]。
文摘The simultaneous control of crystal phase stability and one-dimensional growth has always been the major challenge for the preparation of tetragonal zirconia whiskers.In this study,we report a facile molten salt processing that utilizes CaF_(2) as a stabilizer and adsorbent to meet the phase and morphology requirements.The processes of stabilization,phase transition,ion adsorption and formation of special morphology involved in zirconia growth were investigated by XRD,IR,SEM,DTA-TG and TEM.By controlling the amount of CaF_(2)(15 wt%)added in the reaction precursor,tetragonal zirconia whiskers with a desired aspect ratio(>16)can be synthesized,which show single crystalline nature and[001]preferred direction.Ca ions doped at low temperature inhibit the occurrence of phase transition,which allows the tetragonal structure to be retained to room temperature.The inducement and pattern of whisker growth are supposed to be F-adsorption and screw dislocation elongation,respectively.The specific selectivity of surface adsorbed ions to certain zirconia crystal planes reduces or even inhibits the epitaxial growth rate in this direction,offering a viable avenue for the morphology modulation of inorganic nanomaterials.
