Progenitor Leydig cells are derived from stem cells. The proliferation and differentiation of progenitor Leydig cells significantly contributes to Leydig cell number during puberty. However, the regulation of these pr...Progenitor Leydig cells are derived from stem cells. The proliferation and differentiation of progenitor Leydig cells significantly contributes to Leydig cell number during puberty. However, the regulation of these processes remains unclear. The objective of the present study was to determine whether luteinizing hormone (LH) or androgen contributes to the proliferation and differentiation of progenitor Leydig cells. Fourteen-day-old male Sprague-Dawley rats were treated for 7 days with NalGlu, which is a gonadotropin- releasing hormone antagonist, to reduce the secretion of LH in the pituitary and thus, androgen in the testis. Rats were co-administered with LH or 7a-methyl-nortestosterone (MENT), which is an androgen resistant to metabolism by 5a-reductase 1 in progenitor Leydig cells, and the subsequent effects of LH or androgen were measured. 3H-Thymidine was also intravenously injected into rats to study thymidine incorporation in progenitor Leydig cells. Progenitor Leydig cells were examined. NalGlu administration reduced progenitor Leydig cell proliferation by 83%. In addition, LH or MENT treatment restored Leydig cell proliferative capacity to 73% or 50% of control, respectively. The messenger RNA levels of proliferation-related genes were measured using real-time PCR. The expression levels of Igfl, Lifr, Pdgfra, Bcl2, Ccnd3and Pcnawere upregulated by MENT, and those of Pdgfra, Ccnd3and Pcnawere upregulated by LH. Both LH and MENT stimulated the differentiation of progenitor Leydig cells in vitro. We concluded that both LH and MENT were involved in regulating the development of progenitor Leydig cells.展开更多
AIM:To investigate therapeutic effects of traditional Chinese medicine formulations,Hexuemingmu(HXMM)on laser-induced choroidal neovascularization(CNV)and followup effect in mice.METHODS:C57 BL/6 mice of 8-week-old we...AIM:To investigate therapeutic effects of traditional Chinese medicine formulations,Hexuemingmu(HXMM)on laser-induced choroidal neovascularization(CNV)and followup effect in mice.METHODS:C57 BL/6 mice of 8-week-old were used and CNV was induced with 577 nm laser photocoagulation.Animals were randomly divided into groups and different doses of HXMM were administered daily.One,four,and eight weeks after the intervention,the electroretinogram(ERG),fundus fluorescence angiography,choroidal flat mount and immunofluorescence staining were preformed to evaluate the function and CNV formation.The expression levels of angiogenic proteins were determined by Western blotting and immunofluorescence staining.An analysis of variance and Kruskal-Wallis test were used to test the differences among the groups.RESULTS:The results showed that HXMM effectively increased amplitude of ERG of mice(P<0.05),alleviated fundus CNV leakage(P<0.05),and reduced the area of neovascularization and the expression of angiogenic proteins(P<0.05)after laser-induced CNV.CONCLUSION:HXMM can protect the retinal function of mice after laser-induced CNV,and inhibit the CNV development.展开更多
AIM:To explore the effects of laser-activated remote phosphors(LARP)on visual function in guinea pigs.METHODS:Electroretinogram(ERG)of guinea pigs were observed after LARP irradiation at different frequencies and irra...AIM:To explore the effects of laser-activated remote phosphors(LARP)on visual function in guinea pigs.METHODS:Electroretinogram(ERG)of guinea pigs were observed after LARP irradiation at different frequencies and irradiation times.We evaluated the expression of rhodopsin,β-catenin,connexin36,calretinin,and calbindin in the retina of guinea pigs and measured the density of photoreceptor cells after high-frequency LARP irradiation.RESULTS:After LARP irradiation,the ERG results showed that the amplitude of the dark-adapted 3.0 b-wave of the model eye was lower than that of the control eye after high-frequency irradiation(P<0.05).The expression of rhodopsin,β-catenin,connexin36,calretinin,and calbindin in the retina of guinea pig declined.CONCLUSION:There is frequency cumulative damage effect on the retina that relates to LARP illumination frequency.This has significance for staff visual protection policies under LARP lighting conditions.展开更多
Three-way spacecraft Doppler tracking is currently widely used and it plays an important role in the control and navigation of deep space missions. Using the theory of three-way Doppler tracking, including possible vi...Three-way spacecraft Doppler tracking is currently widely used and it plays an important role in the control and navigation of deep space missions. Using the theory of three-way Doppler tracking, including possible violations of the local Lorentz invariance (LLI) and the local position invariance (LPI), we analyze the post-fit residuals of three-way Doppler tracking data of Mars Express. These Doppler observations were carried out from August 7th to 8th in 2009, with an uplink station administered by the European Space Agency at New Norcia in Australia and three downlink stations at Shanghai, Kunming and Urumqi in China. We find that, although these observations impose preliminary bounds on LLI at the level of 10^-2, they are not suitable for testing LPI because of the configuration of these stations and the accuracy of the observations. To our knowledge, this is one of the first attempts in China to apply radio science to the field of fundamental physics.展开更多
Recently,metal selenides have obtained widespread attention as electrode materials for alkali(Li^(+)/Na^(+)/K^(+))batteries due to their promising theoretical capacity and mechanism.Nevertheless,metal selenides,simila...Recently,metal selenides have obtained widespread attention as electrode materials for alkali(Li^(+)/Na^(+)/K^(+))batteries due to their promising theoretical capacity and mechanism.Nevertheless,metal selenides,similar to metal oxides and sulfides,also suffer from severe volume explosion during repeated charge/discharge processes,which results in the structure collapse and the following pulverization of electrode materials.Hence,it leads to poor cycle stability and influencing their further application.In order to solve these issues,some special strategies,including elemental doping,coupling with carbon materials,synthesis of the bimetal selenides with heterostructure,etc.,have been gradually applied to design novel electrode materials with outstanding electrochemical performance.Herein,the recent research progress on metal selenides as anodes for alkali ion batteries is summarized,including the regulation of crystal structure,synthesis strategies,modification methods,and electrochemical mechanisms and kinetics.Besides,the challenges of metal selenides and the perspective for future electrode material design are proposed.It is hoped to pave a way for the development of metal selenide electrode materials for the potential applications for alkali metal ion(Li^(+)/Na^(+)/K^(+))batteries.展开更多
Due to concerns about carbon leakage and sectoral competitiveness,the European Union(EU)proposed implementing the carbon border adjustment mechanism(CBAM).The effectiveness and potential negative consequences of CBAM ...Due to concerns about carbon leakage and sectoral competitiveness,the European Union(EU)proposed implementing the carbon border adjustment mechanism(CBAM).The effectiveness and potential negative consequences of CBAM have aroused extensive discussion.From the perspective of the economy-wide analysis,this study uses a global computable general equilibrium model to explore the rationality of CBAM from the aspects of socioeconomic impact and the effects of promoting climate mitigation.Furthermore,the potential alternative mechanism of CBAM is proposed.The results show that CBAM can reduce the EU's gross domestic product(GDP)loss;however,the GDP loss in all other regions increases.Moreover,CBAM raises household welfare losses in most regions,including the EU.Second,although CBAM can reduce the marginal abatement cost in eight regions,it comes at the cost of greater economic losses.Furthermore,the economic and household welfare cost of raising emissions reduction targets in regions like the USA and Japan is substantially higher than the impact of passively accepting the CBAM;therefore,CBAM's ability to drive ambitious emission reduction initiatives may be limited.Finally,for the potential alternative mechanism,from the perspective of reducing economic cost and household welfare losses,the EU could implement domestic tax cuts in the short-term and promote global unified carbon pricing in the long-term.展开更多
Sodium-ion batteries(SIBs) and potassium-ion batteries(PIBs) have been attracting great attentions and widely been exploited due to the abundant sodium/potassium resources.Hence,the preparation of high-powered anode m...Sodium-ion batteries(SIBs) and potassium-ion batteries(PIBs) have been attracting great attentions and widely been exploited due to the abundant sodium/potassium resources.Hence,the preparation of high-powered anode materials for SIBs/PIBs plays a decisive role for the commercial applications of SIBs/PIBs in the future.Manganese selenides are a class of potential anode materials for SIBs/PIBs because of their small band gap and high electrical conductivity.In this work,MnSe and ReS_(2) core-shell nanowires connecting by polydopamine derived carbon nanotube(MnSe@NC@ReS_(2)) have been successfully synthesized from growing ReS_(2) nanosheets array on the surface of MnSe@NC nano wires,which present excellent Na^(+)/K^(+) storage performance.While applied as SIBs anode,the specific capacity of 300 mAh·g^(-1) was maintwined after 400 cycles at the current density of 1.0 A·g^(-1).Besides,it could also keep 120 mAh·g^(-1) specific capacity after 900 cycles at 1.0 A·g^(-1) for the anode of PIBs.These heterogeneous engineering and one-dimensional-two-dimensional(1D-2D) hybrid strategies could provide an ideal strategy for the synthesis of new hetero-structured anode materials with outstanding battery performance for SIBs and PIBs.展开更多
Layered nickel oxides have been focused with intense research interests as high-performance lithium-ion batterie(LIB)anode.However,it is hard to obtain few layered nickel oxides material directly as it easily forms bu...Layered nickel oxides have been focused with intense research interests as high-performance lithium-ion batterie(LIB)anode.However,it is hard to obtain few layered nickel oxides material directly as it easily forms bulk material with the strong interaction between the interlayer.In this work,two-dimensional(2 D)nickel-based coordination polymers were successfully prepared according to aqueous phase copolymerization approach.And then uniform carbondoped NiO nanosheets were successfully obtained from facile solution assembly and post-thermal treatment.The detailed electrochemical testing shows that the uniform NiO nanocrystals encapsulated into porous N-doped carbon(NiO@NC)nanosheets present much higher rate capability with the discharge specific capacity of 782.7 mAh·g^(-1) at high current density of 2.0 A·g^(-1) than pure NiO(690 mAh·g^(-1)).It also shows long-term cycling performance with 91%retention after 50 cycles at 1.0 A·g^(-1).The high rate capability,cycling stability and the easy synthesis make NiO@NC nanosheets as a promising candidate for LIB anode and build up new way for the fabrication of metal oxides anode materials.展开更多
Silver vanadate(Ag_(0.33)V_(2)O_(5))nanorods were successfully synthesized by the pre-intercalation of Ag+into the interlayer of V_(2)O_(5)through a sol-gel method,which presented a favorable electrochemical performan...Silver vanadate(Ag_(0.33)V_(2)O_(5))nanorods were successfully synthesized by the pre-intercalation of Ag+into the interlayer of V_(2)O_(5)through a sol-gel method,which presented a favorable electrochemical performance of high capacity,rate capacity,and cycle stability.Specific ally,Ag_(0.33)V_(2)O_(5)electrode presented a high capacity of about 311 mAh·g^(-1)at the current density of0.1 A·g^(-1).It also delivered long-term cycling stability(144 mAh·g^(-1)after 500 cycles at 2 A·g^(-1)).The reasons for the superior electrochemical performance were the preintercalation Ag^+extended interlayer distance,and the introduction of elemental silver improved conductivity during charge/discharge.Additionally,the Zn^(2+)storage mechanism was revealed by various characteristic measurements.The prepared Ag_(0.33)V_(2)O_(5)nanorods from the sol-gel method were demonstrated as a promising cathode material for aqueous Zn^(2+)batteries.展开更多
Bimetallic selenide with core-shell structure(CoSe_(2)/ZnSe/NC@ZnSe/NC)has been successfully prepared through facile carbonization and selenization processes of its core-shell metal-organic framework precursors,in whi...Bimetallic selenide with core-shell structure(CoSe_(2)/ZnSe/NC@ZnSe/NC)has been successfully prepared through facile carbonization and selenization processes of its core-shell metal-organic framework precursors,in which the precursor is synthesized by epitaxial growth of zinc-based zeolite imidazolate framework(ZIF-8)on the surface of cobalt-based and zinc-based zeolite imidazolate framework(ZIF-67@ZIF-8).The coreshell structure has the advantage of alleviating the volume expansion during repeated insertion and extraction of sodium ions which can effectively avoid structural collapse.Additionally,bimetallic selenides and heterostructure are effective strategies to greatly improve the rate capability of the material.Therefore,the core-shell structural CoSe2/ZnSe/NC@ZnSe/NC material can maintain the original dodecahedron structure and delivers a specific capacity of 308.6 mAh·g^(-1)at 1.0 A·g^(-1)after 300 cycles with the desirable capacity retention of 90%.With the synergistic effects of heterostructure and core-shell structure,CoSe_(2)/ZnSe/NC@ZnSe/NC exhibits better electrochemical performance than CoSe_(2)/ZnSe/NC and CoSe_(2)/NC.These prove that both core-shell structure and heterostructure have positive effects on improving the electrochemical properties of materials.展开更多
TEMPO(2,2,6,6-tetramethylpipe ridine-1-oxyl)is well-established in orangocatalysis that usually work in synergy with transition-metal catalysis or semiconductor photocatalysis.Here,TEMPO was turned into a visible ligh...TEMPO(2,2,6,6-tetramethylpipe ridine-1-oxyl)is well-established in orangocatalysis that usually work in synergy with transition-metal catalysis or semiconductor photocatalysis.Here,TEMPO was turned into a visible light photocatalyst to conduct the selective aerobic oxidation of thiols into disulfides.With O2 as an oxidant,a mild and efficient protocol for the selective oxidation of thiols into disulfides including symmetrical and unsymmetrical ones with 5 mol%of TEPMO as a photocatalyst was developed at room temperature under the irradiation of 460 nm blue LEDs.It was found that a complex formed between TEMPO and thiols underpinned the visible light activity and disulfides were obtained in very high isolated yields.This work suggests that TEMPO takes diverse roles in for photocatalytic selective oxidative transformations with O2 as the oxidant.展开更多
基金We are grateful to Ms Chantal Sottas for technical assistance. This work was in part supported by the National Nature Science Foundation of China (nos. 30871434 and 31171425 to RS Ge, no. 30900846 to CQ Wang and no. 81200430 to YF Zhang).
文摘Progenitor Leydig cells are derived from stem cells. The proliferation and differentiation of progenitor Leydig cells significantly contributes to Leydig cell number during puberty. However, the regulation of these processes remains unclear. The objective of the present study was to determine whether luteinizing hormone (LH) or androgen contributes to the proliferation and differentiation of progenitor Leydig cells. Fourteen-day-old male Sprague-Dawley rats were treated for 7 days with NalGlu, which is a gonadotropin- releasing hormone antagonist, to reduce the secretion of LH in the pituitary and thus, androgen in the testis. Rats were co-administered with LH or 7a-methyl-nortestosterone (MENT), which is an androgen resistant to metabolism by 5a-reductase 1 in progenitor Leydig cells, and the subsequent effects of LH or androgen were measured. 3H-Thymidine was also intravenously injected into rats to study thymidine incorporation in progenitor Leydig cells. Progenitor Leydig cells were examined. NalGlu administration reduced progenitor Leydig cell proliferation by 83%. In addition, LH or MENT treatment restored Leydig cell proliferative capacity to 73% or 50% of control, respectively. The messenger RNA levels of proliferation-related genes were measured using real-time PCR. The expression levels of Igfl, Lifr, Pdgfra, Bcl2, Ccnd3and Pcnawere upregulated by MENT, and those of Pdgfra, Ccnd3and Pcnawere upregulated by LH. Both LH and MENT stimulated the differentiation of progenitor Leydig cells in vitro. We concluded that both LH and MENT were involved in regulating the development of progenitor Leydig cells.
基金the Army Laboratory Animal Foundation of China(No.SYDW2016-011)。
文摘AIM:To investigate therapeutic effects of traditional Chinese medicine formulations,Hexuemingmu(HXMM)on laser-induced choroidal neovascularization(CNV)and followup effect in mice.METHODS:C57 BL/6 mice of 8-week-old were used and CNV was induced with 577 nm laser photocoagulation.Animals were randomly divided into groups and different doses of HXMM were administered daily.One,four,and eight weeks after the intervention,the electroretinogram(ERG),fundus fluorescence angiography,choroidal flat mount and immunofluorescence staining were preformed to evaluate the function and CNV formation.The expression levels of angiogenic proteins were determined by Western blotting and immunofluorescence staining.An analysis of variance and Kruskal-Wallis test were used to test the differences among the groups.RESULTS:The results showed that HXMM effectively increased amplitude of ERG of mice(P<0.05),alleviated fundus CNV leakage(P<0.05),and reduced the area of neovascularization and the expression of angiogenic proteins(P<0.05)after laser-induced CNV.CONCLUSION:HXMM can protect the retinal function of mice after laser-induced CNV,and inhibit the CNV development.
基金Supported by the Key Research Plan of Shaanxi Province,China(No.2018SF-257)the Key Project of Equipment Scientific Research(No.172B02027)。
文摘AIM:To explore the effects of laser-activated remote phosphors(LARP)on visual function in guinea pigs.METHODS:Electroretinogram(ERG)of guinea pigs were observed after LARP irradiation at different frequencies and irradiation times.We evaluated the expression of rhodopsin,β-catenin,connexin36,calretinin,and calbindin in the retina of guinea pigs and measured the density of photoreceptor cells after high-frequency LARP irradiation.RESULTS:After LARP irradiation,the ERG results showed that the amplitude of the dark-adapted 3.0 b-wave of the model eye was lower than that of the control eye after high-frequency irradiation(P<0.05).The expression of rhodopsin,β-catenin,connexin36,calretinin,and calbindin in the retina of guinea pig declined.CONCLUSION:There is frequency cumulative damage effect on the retina that relates to LARP illumination frequency.This has significance for staff visual protection policies under LARP lighting conditions.
基金Supported by the National Natural Science Foundation of China
文摘Three-way spacecraft Doppler tracking is currently widely used and it plays an important role in the control and navigation of deep space missions. Using the theory of three-way Doppler tracking, including possible violations of the local Lorentz invariance (LLI) and the local position invariance (LPI), we analyze the post-fit residuals of three-way Doppler tracking data of Mars Express. These Doppler observations were carried out from August 7th to 8th in 2009, with an uplink station administered by the European Space Agency at New Norcia in Australia and three downlink stations at Shanghai, Kunming and Urumqi in China. We find that, although these observations impose preliminary bounds on LLI at the level of 10^-2, they are not suitable for testing LPI because of the configuration of these stations and the accuracy of the observations. To our knowledge, this is one of the first attempts in China to apply radio science to the field of fundamental physics.
基金supported by the National Natural Science Foundation of China(Nos.51563002 and 52101243)the"100-level"Innovative Talents Project of Guizhou Province,China(No.[2016]5653)+1 种基金the Natural Science Foundation of Guangdong Province(No.2020A1515010886)the Science and Technology Planning Project of Guangzhou(No.202102010373)。
文摘Recently,metal selenides have obtained widespread attention as electrode materials for alkali(Li^(+)/Na^(+)/K^(+))batteries due to their promising theoretical capacity and mechanism.Nevertheless,metal selenides,similar to metal oxides and sulfides,also suffer from severe volume explosion during repeated charge/discharge processes,which results in the structure collapse and the following pulverization of electrode materials.Hence,it leads to poor cycle stability and influencing their further application.In order to solve these issues,some special strategies,including elemental doping,coupling with carbon materials,synthesis of the bimetal selenides with heterostructure,etc.,have been gradually applied to design novel electrode materials with outstanding electrochemical performance.Herein,the recent research progress on metal selenides as anodes for alkali ion batteries is summarized,including the regulation of crystal structure,synthesis strategies,modification methods,and electrochemical mechanisms and kinetics.Besides,the challenges of metal selenides and the perspective for future electrode material design are proposed.It is hoped to pave a way for the development of metal selenide electrode materials for the potential applications for alkali metal ion(Li^(+)/Na^(+)/K^(+))batteries.
基金the National Natural Science Foundation of China(72293605,72293600,72204013,72074022)R&D Program of Beijing Municipal Education Commission(SM202310005005)China Postdoctoral Science Foundation(2021M700314,2023T160035).
文摘Due to concerns about carbon leakage and sectoral competitiveness,the European Union(EU)proposed implementing the carbon border adjustment mechanism(CBAM).The effectiveness and potential negative consequences of CBAM have aroused extensive discussion.From the perspective of the economy-wide analysis,this study uses a global computable general equilibrium model to explore the rationality of CBAM from the aspects of socioeconomic impact and the effects of promoting climate mitigation.Furthermore,the potential alternative mechanism of CBAM is proposed.The results show that CBAM can reduce the EU's gross domestic product(GDP)loss;however,the GDP loss in all other regions increases.Moreover,CBAM raises household welfare losses in most regions,including the EU.Second,although CBAM can reduce the marginal abatement cost in eight regions,it comes at the cost of greater economic losses.Furthermore,the economic and household welfare cost of raising emissions reduction targets in regions like the USA and Japan is substantially higher than the impact of passively accepting the CBAM;therefore,CBAM's ability to drive ambitious emission reduction initiatives may be limited.Finally,for the potential alternative mechanism,from the perspective of reducing economic cost and household welfare losses,the EU could implement domestic tax cuts in the short-term and promote global unified carbon pricing in the long-term.
基金financially supported by the National Natural Science Foundation of China (No.52101243)the Natural Science Foundation of Guangdong Province (No.2023A1515012619)the Science and Technology Planning Project of Guangzhou (No.202102010373)。
文摘Sodium-ion batteries(SIBs) and potassium-ion batteries(PIBs) have been attracting great attentions and widely been exploited due to the abundant sodium/potassium resources.Hence,the preparation of high-powered anode materials for SIBs/PIBs plays a decisive role for the commercial applications of SIBs/PIBs in the future.Manganese selenides are a class of potential anode materials for SIBs/PIBs because of their small band gap and high electrical conductivity.In this work,MnSe and ReS_(2) core-shell nanowires connecting by polydopamine derived carbon nanotube(MnSe@NC@ReS_(2)) have been successfully synthesized from growing ReS_(2) nanosheets array on the surface of MnSe@NC nano wires,which present excellent Na^(+)/K^(+) storage performance.While applied as SIBs anode,the specific capacity of 300 mAh·g^(-1) was maintwined after 400 cycles at the current density of 1.0 A·g^(-1).Besides,it could also keep 120 mAh·g^(-1) specific capacity after 900 cycles at 1.0 A·g^(-1) for the anode of PIBs.These heterogeneous engineering and one-dimensional-two-dimensional(1D-2D) hybrid strategies could provide an ideal strategy for the synthesis of new hetero-structured anode materials with outstanding battery performance for SIBs and PIBs.
基金financially supported by the National Natural Science Foundation of China(No.21676060)the Natural Science Foundation of Guangdong Province of China(No.2018A030313516)the Science and Technology Planning Project of Guangzhou(No.201804010449)。
文摘Layered nickel oxides have been focused with intense research interests as high-performance lithium-ion batterie(LIB)anode.However,it is hard to obtain few layered nickel oxides material directly as it easily forms bulk material with the strong interaction between the interlayer.In this work,two-dimensional(2 D)nickel-based coordination polymers were successfully prepared according to aqueous phase copolymerization approach.And then uniform carbondoped NiO nanosheets were successfully obtained from facile solution assembly and post-thermal treatment.The detailed electrochemical testing shows that the uniform NiO nanocrystals encapsulated into porous N-doped carbon(NiO@NC)nanosheets present much higher rate capability with the discharge specific capacity of 782.7 mAh·g^(-1) at high current density of 2.0 A·g^(-1) than pure NiO(690 mAh·g^(-1)).It also shows long-term cycling performance with 91%retention after 50 cycles at 1.0 A·g^(-1).The high rate capability,cycling stability and the easy synthesis make NiO@NC nanosheets as a promising candidate for LIB anode and build up new way for the fabrication of metal oxides anode materials.
基金financially supported by the National Natural Science Foundation of China (No.52101243)the Natural Science Foundation of Guangdong Province (No. 2020A1515010886)the Science and Technology Planning Project of Guangzhou (No.202102010373)
文摘Silver vanadate(Ag_(0.33)V_(2)O_(5))nanorods were successfully synthesized by the pre-intercalation of Ag+into the interlayer of V_(2)O_(5)through a sol-gel method,which presented a favorable electrochemical performance of high capacity,rate capacity,and cycle stability.Specific ally,Ag_(0.33)V_(2)O_(5)electrode presented a high capacity of about 311 mAh·g^(-1)at the current density of0.1 A·g^(-1).It also delivered long-term cycling stability(144 mAh·g^(-1)after 500 cycles at 2 A·g^(-1)).The reasons for the superior electrochemical performance were the preintercalation Ag^+extended interlayer distance,and the introduction of elemental silver improved conductivity during charge/discharge.Additionally,the Zn^(2+)storage mechanism was revealed by various characteristic measurements.The prepared Ag_(0.33)V_(2)O_(5)nanorods from the sol-gel method were demonstrated as a promising cathode material for aqueous Zn^(2+)batteries.
基金financially supported by the National Natural Science Foundation of China(Nos.52101243 and 51563002)the Natural Science Foundation of Guangdong Province(Nos.2020A1515010886 and 2021A1515010078)+1 种基金the Scientific and Technological Plan of Guangdong Province,China(No.2019B090905007)the Science and Technology Planning Project of Guangzhou(No.202102010373)。
文摘Bimetallic selenide with core-shell structure(CoSe_(2)/ZnSe/NC@ZnSe/NC)has been successfully prepared through facile carbonization and selenization processes of its core-shell metal-organic framework precursors,in which the precursor is synthesized by epitaxial growth of zinc-based zeolite imidazolate framework(ZIF-8)on the surface of cobalt-based and zinc-based zeolite imidazolate framework(ZIF-67@ZIF-8).The coreshell structure has the advantage of alleviating the volume expansion during repeated insertion and extraction of sodium ions which can effectively avoid structural collapse.Additionally,bimetallic selenides and heterostructure are effective strategies to greatly improve the rate capability of the material.Therefore,the core-shell structural CoSe2/ZnSe/NC@ZnSe/NC material can maintain the original dodecahedron structure and delivers a specific capacity of 308.6 mAh·g^(-1)at 1.0 A·g^(-1)after 300 cycles with the desirable capacity retention of 90%.With the synergistic effects of heterostructure and core-shell structure,CoSe_(2)/ZnSe/NC@ZnSe/NC exhibits better electrochemical performance than CoSe_(2)/ZnSe/NC and CoSe_(2)/NC.These prove that both core-shell structure and heterostructure have positive effects on improving the electrochemical properties of materials.
基金supported by the National Natural Science Foundation of China(Nos.21773173,21503086)the Fundamental Research Funds for the Central Universities(No.2042018kf0212)the start-up fund of Wuhan University。
文摘TEMPO(2,2,6,6-tetramethylpipe ridine-1-oxyl)is well-established in orangocatalysis that usually work in synergy with transition-metal catalysis or semiconductor photocatalysis.Here,TEMPO was turned into a visible light photocatalyst to conduct the selective aerobic oxidation of thiols into disulfides.With O2 as an oxidant,a mild and efficient protocol for the selective oxidation of thiols into disulfides including symmetrical and unsymmetrical ones with 5 mol%of TEPMO as a photocatalyst was developed at room temperature under the irradiation of 460 nm blue LEDs.It was found that a complex formed between TEMPO and thiols underpinned the visible light activity and disulfides were obtained in very high isolated yields.This work suggests that TEMPO takes diverse roles in for photocatalytic selective oxidative transformations with O2 as the oxidant.