The study of the chlorite coatings always attracts scholars in China and other countries because the chlorite coatings play an important role in the preservation of residual primary pores in sandstone reservoirs.At pr...The study of the chlorite coatings always attracts scholars in China and other countries because the chlorite coatings play an important role in the preservation of residual primary pores in sandstone reservoirs.At present,the study of the origin and the controlling factors is relatively few.The occurrence,time of formation,genesis,controlling factors,and the mechanism of chlorite coatings inhibiting quartz overgrowths were studied in detail with thin section and SEM analysis.Samples were from the sandstone reservoirs of the T3x Group in the Baojie area,the transitional zone from the middle to the south of Sichuan Basin.The results indicate that the chlorite coatings on the walls of the pore spaces are oriented perpendicular to grain surfaces in the form of isopachous(even-thickness) grain-coating,while the chlorite coatings at the contacts between adjacent detrital grains are arranged with a preferred orientation tangential to the surface of detrital grains.The chlorite coatings were formed in the eogenetic stage.They were formed by recrystallization of Fe-rich clay films during the syndepositional period,and chlorite cements would be recrystallized after the coatings’ formation.The formation of chlorite coatings was mainly controlled by the depositional environment,provenance conditions,and diagenetic environment.The presence of chlorite coatings could result in the preservation of primary pores in deeply buried sandstone reservoirs by effectively inhibiting quartz overgrowths and the development of compaction and pressure solution.展开更多
Due to their large surface-to-volume ratio and low electronic noise,two-dimensional transition metal carbides(Ti_(3)C_(2)T_(x) MXene)and their derived transition metal oxides have demonstrated significant potential fo...Due to their large surface-to-volume ratio and low electronic noise,two-dimensional transition metal carbides(Ti_(3)C_(2)T_(x) MXene)and their derived transition metal oxides have demonstrated significant potential for use in high-precision gas sensing.However,the construction of high-sensitivity Ti_(3)C_(2)T_(x) MXene-based gas sensors operated at room temperature(RT)is still a major challenge.Herein,we demonstrate a sensitive nanocomposite prepared by uniformly anchoring silver nanoparticles(AgNPs)on Ti_(3)C_(2)T_(x) MXene-derived transition metal oxide(TiO_(2))nanosheets for high-sensitivity NH_(3) detection.AgNPs can not only serve as spacers to effectively prevent the restacking of MXene-derived TiO_(2)nanosheets and ensure an effective transmission highway for target gas molecules,but also enhance the sensitivity of the sensor through chemical and electronic sensitization.By integrating the unique merits of the individual components and the synergistic effects of the composites,the optimized Ag@TiO_(2)nanocomposite-based sensors revealed an extraordinary response value of 71.8 to 50 ppm NH_(3) at RT with a detection limit as low as 5 ppm.In addition,the Ag@TiO_(2)NH_(3) sensor also exhibits excellent selectivity and outstanding repeatability.This strategy provides an avenue for the development of MXene derivatives for advanced gas sensors.展开更多
The isothermal section of the Ho-Fe-In system at 773 K has been constructed by X-ray powder diffraction.One known structure ternary compound Er_(12)Fe_(2) In_(3)-type Ho_(12)Fe_(2) In_(3) has been confirmed.At the sam...The isothermal section of the Ho-Fe-In system at 773 K has been constructed by X-ray powder diffraction.One known structure ternary compound Er_(12)Fe_(2) In_(3)-type Ho_(12)Fe_(2) In_(3) has been confirmed.At the same time,solid solutions are not detected in Ho-Fe-In system at 773 K.The magnetic transition and magnetocaloric effect of Ho_(12)Fe_(2.08)In_(2.92) alloy with Er_(12)Fe_(2) In_(3)-type structure were investigated by magnetic susceptibility and isothermal magnetization measurements.One normal antiferromagnetic-paramagnetic transition and another abnormal one are discovered at 18 and 76 K in ground state,respectively.Owing to a first-order field-induced metamagnetic transition(antiferromagnetic-ferromagnetic) at/below the Neel temperature of 18 K),the negative entropy changes are observed at corresponding temperature.There is only a second-order ferromagnetic-paramagnetic transition near Curie temperature(TC),the maximum entropy change(Δ_(Smax)) values are-6.14 J·kg^(-1)·K^(-1) at 3 K and 7.88 J·kg^(-1)·K^(-1) at 28 K in a field range of 0-7 T.The reversible relative cooling power corresponding to negative entropy change can reach about 600 J·kg^(-1) in an wide operating temperature region Δ_(Tcycl)=74 K from 16 to90 K,which suggests that Ho_(12)Fe_(2.08)In_(2.92) could be a potential material for magnetic refrigeration in the corresponding temperature range.展开更多
基金supported by the Natural Science Key Project of Education Board in Sichuan province,China (No.07ZA139)
文摘The study of the chlorite coatings always attracts scholars in China and other countries because the chlorite coatings play an important role in the preservation of residual primary pores in sandstone reservoirs.At present,the study of the origin and the controlling factors is relatively few.The occurrence,time of formation,genesis,controlling factors,and the mechanism of chlorite coatings inhibiting quartz overgrowths were studied in detail with thin section and SEM analysis.Samples were from the sandstone reservoirs of the T3x Group in the Baojie area,the transitional zone from the middle to the south of Sichuan Basin.The results indicate that the chlorite coatings on the walls of the pore spaces are oriented perpendicular to grain surfaces in the form of isopachous(even-thickness) grain-coating,while the chlorite coatings at the contacts between adjacent detrital grains are arranged with a preferred orientation tangential to the surface of detrital grains.The chlorite coatings were formed in the eogenetic stage.They were formed by recrystallization of Fe-rich clay films during the syndepositional period,and chlorite cements would be recrystallized after the coatings’ formation.The formation of chlorite coatings was mainly controlled by the depositional environment,provenance conditions,and diagenetic environment.The presence of chlorite coatings could result in the preservation of primary pores in deeply buried sandstone reservoirs by effectively inhibiting quartz overgrowths and the development of compaction and pressure solution.
基金supported by the National Natural Science Foundation of China (No. 52103308)the Postgraduate Research & Practice Innovation Program of Jiangsu Province (No. SJCX21_1555)the Natural Science Foundation of Jiangsu Province (No. BK20210826)
文摘Due to their large surface-to-volume ratio and low electronic noise,two-dimensional transition metal carbides(Ti_(3)C_(2)T_(x) MXene)and their derived transition metal oxides have demonstrated significant potential for use in high-precision gas sensing.However,the construction of high-sensitivity Ti_(3)C_(2)T_(x) MXene-based gas sensors operated at room temperature(RT)is still a major challenge.Herein,we demonstrate a sensitive nanocomposite prepared by uniformly anchoring silver nanoparticles(AgNPs)on Ti_(3)C_(2)T_(x) MXene-derived transition metal oxide(TiO_(2))nanosheets for high-sensitivity NH_(3) detection.AgNPs can not only serve as spacers to effectively prevent the restacking of MXene-derived TiO_(2)nanosheets and ensure an effective transmission highway for target gas molecules,but also enhance the sensitivity of the sensor through chemical and electronic sensitization.By integrating the unique merits of the individual components and the synergistic effects of the composites,the optimized Ag@TiO_(2)nanocomposite-based sensors revealed an extraordinary response value of 71.8 to 50 ppm NH_(3) at RT with a detection limit as low as 5 ppm.In addition,the Ag@TiO_(2)NH_(3) sensor also exhibits excellent selectivity and outstanding repeatability.This strategy provides an avenue for the development of MXene derivatives for advanced gas sensors.
基金financially supported by the Department of Science and Technology of Sichuan Province in China(No.2017JY0181)。
文摘The isothermal section of the Ho-Fe-In system at 773 K has been constructed by X-ray powder diffraction.One known structure ternary compound Er_(12)Fe_(2) In_(3)-type Ho_(12)Fe_(2) In_(3) has been confirmed.At the same time,solid solutions are not detected in Ho-Fe-In system at 773 K.The magnetic transition and magnetocaloric effect of Ho_(12)Fe_(2.08)In_(2.92) alloy with Er_(12)Fe_(2) In_(3)-type structure were investigated by magnetic susceptibility and isothermal magnetization measurements.One normal antiferromagnetic-paramagnetic transition and another abnormal one are discovered at 18 and 76 K in ground state,respectively.Owing to a first-order field-induced metamagnetic transition(antiferromagnetic-ferromagnetic) at/below the Neel temperature of 18 K),the negative entropy changes are observed at corresponding temperature.There is only a second-order ferromagnetic-paramagnetic transition near Curie temperature(TC),the maximum entropy change(Δ_(Smax)) values are-6.14 J·kg^(-1)·K^(-1) at 3 K and 7.88 J·kg^(-1)·K^(-1) at 28 K in a field range of 0-7 T.The reversible relative cooling power corresponding to negative entropy change can reach about 600 J·kg^(-1) in an wide operating temperature region Δ_(Tcycl)=74 K from 16 to90 K,which suggests that Ho_(12)Fe_(2.08)In_(2.92) could be a potential material for magnetic refrigeration in the corresponding temperature range.
