An efficient catalyst SO4^2--TiO2(ST) from industrial metatitanic acid has been successfully prepared to catalyze hydrolysis of ball-milling cellulose. The results show that the highest catalytic efficiency is obtaine...An efficient catalyst SO4^2--TiO2(ST) from industrial metatitanic acid has been successfully prepared to catalyze hydrolysis of ball-milling cellulose. The results show that the highest catalytic efficiency is obtained for ST calcined at 450 ℃(ST-450) with the yield of 21.8% glucose, 13.0% 5-HMF and 4.2% furfural at 200 ℃ for30 min. The ball milling of cellulose and solid acid catalyst significantly enhances the cellulose hydrolysis. The high Lewis to Bronsted acid sites ratio for ST-450 induced by bidentate ligands between SO4^2-and TiO2 benefits high organics yield, and high total acid sites contribute to the high cellulose conversion. The large pore volume of 0.29 cm^3·g^-1 and appropriate pore size of 7.35 nm of ST-450 also contribute to the high performance. High reaction temperature over 200 ℃ exhibits negative effect on glucose and 5-HMF yield due to undesired side reactions, while furfural product is stable in the reaction system. The bidentate ligands between SO4^2-and TiO2 are considered as active acid sites for cellulose hydrolysis in water–ethanol solvents.展开更多
The vigorous development of two-dimensional(2D)materials brings about numerous opportunities for lithiumion batteries(LIBs)due to their unique 2D layered structure,large specific surface area,outstanding mechanical an...The vigorous development of two-dimensional(2D)materials brings about numerous opportunities for lithiumion batteries(LIBs)due to their unique 2D layered structure,large specific surface area,outstanding mechanical and flexibility properties,etc.Modern technologies for production of 2D materials include but are not limited to mechanochemical(solid-state/liquid-phase)exfoliation,the solvothermal method and chemical vapor deposition.In this review,strategies leading to the production of 2D materials via solid-state mechanochemistry featuring traditional high energy ball-milling and Sichuan University patented pan-milling are highlighted.The mechanism involving exfoliation,edge selective carbon radical generation of the 2D materials is delineated and this is followed by detailed discussion on representative mechanochemical techniques for tailored and improved lithium-ion storage performance.In the light of the advantages of the solid-state mechanochemical method,there is great promise for the commercialization of 2D materials for the next-generation high performance LIBs.展开更多
A composite of SnS_(2)and carbon nanotube(CNT)was successfully synthesized as a visible-light-driven photocatalyst with a mechanochemical method.In comparing with SnS_(2),the SnS_(2)/CNT composite im-proved much the p...A composite of SnS_(2)and carbon nanotube(CNT)was successfully synthesized as a visible-light-driven photocatalyst with a mechanochemical method.In comparing with SnS_(2),the SnS_(2)/CNT composite im-proved much the photocatalytic removal of Cr(VI)in acidic condition,which was confirmed to its special solid acid structure.During the synthesis of the SnS_(2)/CNT composite by ball milling,S-C p-πbonding was formed between sulfur atoms in SnS_(2)and carbon atoms in CNT.The generated S-C p-πbonding enhanced the transfer of photo-induced electrons in the bulk phase of the composite photocatalyst un-der visible light irradiation.Moreover,the persistent radical sites on CNT were able to trap photo-induced electrons and served as conjugated acid sites in the photocatalysis,which increased surface concentration of protons through their association with H+.These made the catalyst have a solid acid structure with plentiful surface protons,promoting the interfacial electron transfer between the catalysts and Cr(VI)and increasing the source of H+for the reduction of Cr(VI).As a result,the photocatalytic reduction rate of Cr(VI)on the SnS_(2)/CNT composite were dramatically enhanced,being about 800%that on SnS_(2).On the basis of various characterizations and probe experiments,we confirmed the significance of the solid acid structure of the photocatalyst and clarified the catalytic mechanism of the new photocatalyst.Our finding may provide a new strategy to prepare highly active photocatalysts for proton-involved reactions.展开更多
The scuffing behavior of hybrid ceramic bearing lubricated with solid is greatly affected by the contact flash temperature. Formulas are dedused using Lee’s asperity flash temperature method, to calculate the flash t...The scuffing behavior of hybrid ceramic bearing lubricated with solid is greatly affected by the contact flash temperature. Formulas are dedused using Lee’s asperity flash temperature method, to calculate the flash temperature of ball bearing lubricated with solid. The maximum flash temperature is calculated for hybrid ceramic ball bearings. The results show that under given conditions, the flash temperature of inner race is higher than that of outer race, the flash temperature of the hybrid ceramic bearing is sensitive to the load, rotational speed and race curvature. The flash temperature of inner race at 20 000 r/min is 66 9% more than that that at 11 000 r/min, and with the load changing from 1.1 kN to 2 kN, the flash temperature inner race goes up to 165 7%. Very common for high speed ball bearings, when curvature coefficients of both inner and outer race change from 0 515 to 0 56, the inner race flash temperature decreases from 421 446℃ to 56 2℃.展开更多
We fabricated a silver ion emitter based on the solid state electrolyte film of RbAg4 I5 prepared by pulsed laser deposition. The RbAg4 I5 target for PLD process was mechano-chemically synthesized by high-energy ball ...We fabricated a silver ion emitter based on the solid state electrolyte film of RbAg4 I5 prepared by pulsed laser deposition. The RbAg4 I5 target for PLD process was mechano-chemically synthesized by high-energy ball milling in Ar atmosphere using β-AgI and RbI as raw materials. The ion-conducting properties of RbAg4 I5 were studied by alternating current(AC) impedance spectroscopy and the ionic conductivity at room temperature was estimated 0.21 S/m. The structure, morphology, and elemental composition of the RbAg4 I5 film were investigated. The Ag+ ion-conducting property of the prepared superioni-conductor film was exploited for ion–beam generation. The temperature and accelerating voltage dependences of the ion current were studied. Few nA current was obtained at the temperature of 196?C and the accelerating voltage of 10 kV.展开更多
基金Supported by the Key Program of National Natural Science Foundation of China(No.21336008).
文摘An efficient catalyst SO4^2--TiO2(ST) from industrial metatitanic acid has been successfully prepared to catalyze hydrolysis of ball-milling cellulose. The results show that the highest catalytic efficiency is obtained for ST calcined at 450 ℃(ST-450) with the yield of 21.8% glucose, 13.0% 5-HMF and 4.2% furfural at 200 ℃ for30 min. The ball milling of cellulose and solid acid catalyst significantly enhances the cellulose hydrolysis. The high Lewis to Bronsted acid sites ratio for ST-450 induced by bidentate ligands between SO4^2-and TiO2 benefits high organics yield, and high total acid sites contribute to the high cellulose conversion. The large pore volume of 0.29 cm^3·g^-1 and appropriate pore size of 7.35 nm of ST-450 also contribute to the high performance. High reaction temperature over 200 ℃ exhibits negative effect on glucose and 5-HMF yield due to undesired side reactions, while furfural product is stable in the reaction system. The bidentate ligands between SO4^2-and TiO2 are considered as active acid sites for cellulose hydrolysis in water–ethanol solvents.
基金financially supported by the National Natural Science Foundation of China(No.51933007,51673123)the National Key R&D Program of China(No.2017YFE0111500)the Program for Featured Directions of Engineering Multidisciplines of Sichuan University(No.2020SCUNG203)。
文摘The vigorous development of two-dimensional(2D)materials brings about numerous opportunities for lithiumion batteries(LIBs)due to their unique 2D layered structure,large specific surface area,outstanding mechanical and flexibility properties,etc.Modern technologies for production of 2D materials include but are not limited to mechanochemical(solid-state/liquid-phase)exfoliation,the solvothermal method and chemical vapor deposition.In this review,strategies leading to the production of 2D materials via solid-state mechanochemistry featuring traditional high energy ball-milling and Sichuan University patented pan-milling are highlighted.The mechanism involving exfoliation,edge selective carbon radical generation of the 2D materials is delineated and this is followed by detailed discussion on representative mechanochemical techniques for tailored and improved lithium-ion storage performance.In the light of the advantages of the solid-state mechanochemical method,there is great promise for the commercialization of 2D materials for the next-generation high performance LIBs.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.21906184,22076007)the Fundamental Research Funds for the Central Universities,South-Central University for Nationalities(No.CZQ23008).
文摘A composite of SnS_(2)and carbon nanotube(CNT)was successfully synthesized as a visible-light-driven photocatalyst with a mechanochemical method.In comparing with SnS_(2),the SnS_(2)/CNT composite im-proved much the photocatalytic removal of Cr(VI)in acidic condition,which was confirmed to its special solid acid structure.During the synthesis of the SnS_(2)/CNT composite by ball milling,S-C p-πbonding was formed between sulfur atoms in SnS_(2)and carbon atoms in CNT.The generated S-C p-πbonding enhanced the transfer of photo-induced electrons in the bulk phase of the composite photocatalyst un-der visible light irradiation.Moreover,the persistent radical sites on CNT were able to trap photo-induced electrons and served as conjugated acid sites in the photocatalysis,which increased surface concentration of protons through their association with H+.These made the catalyst have a solid acid structure with plentiful surface protons,promoting the interfacial electron transfer between the catalysts and Cr(VI)and increasing the source of H+for the reduction of Cr(VI).As a result,the photocatalytic reduction rate of Cr(VI)on the SnS_(2)/CNT composite were dramatically enhanced,being about 800%that on SnS_(2).On the basis of various characterizations and probe experiments,we confirmed the significance of the solid acid structure of the photocatalyst and clarified the catalytic mechanism of the new photocatalyst.Our finding may provide a new strategy to prepare highly active photocatalysts for proton-involved reactions.
文摘The scuffing behavior of hybrid ceramic bearing lubricated with solid is greatly affected by the contact flash temperature. Formulas are dedused using Lee’s asperity flash temperature method, to calculate the flash temperature of ball bearing lubricated with solid. The maximum flash temperature is calculated for hybrid ceramic ball bearings. The results show that under given conditions, the flash temperature of inner race is higher than that of outer race, the flash temperature of the hybrid ceramic bearing is sensitive to the load, rotational speed and race curvature. The flash temperature of inner race at 20 000 r/min is 66 9% more than that that at 11 000 r/min, and with the load changing from 1.1 kN to 2 kN, the flash temperature inner race goes up to 165 7%. Very common for high speed ball bearings, when curvature coefficients of both inner and outer race change from 0 515 to 0 56, the inner race flash temperature decreases from 421 446℃ to 56 2℃.
基金Project supported by the National Natural Science Foundation of China(Grant No.11875210)China Postdoctoral Science Foundation(Grant No.2018M640724)+1 种基金the International Cooperation Program of Guangdong Provincial Science and Technology Plan Project(Grant No.2018A050506082)the Talent Project of Lingnan Normal University,China(Grant No.ZL1931)
文摘We fabricated a silver ion emitter based on the solid state electrolyte film of RbAg4 I5 prepared by pulsed laser deposition. The RbAg4 I5 target for PLD process was mechano-chemically synthesized by high-energy ball milling in Ar atmosphere using β-AgI and RbI as raw materials. The ion-conducting properties of RbAg4 I5 were studied by alternating current(AC) impedance spectroscopy and the ionic conductivity at room temperature was estimated 0.21 S/m. The structure, morphology, and elemental composition of the RbAg4 I5 film were investigated. The Ag+ ion-conducting property of the prepared superioni-conductor film was exploited for ion–beam generation. The temperature and accelerating voltage dependences of the ion current were studied. Few nA current was obtained at the temperature of 196?C and the accelerating voltage of 10 kV.
