Changes to the microstructure of a hard carbon(HC)and its solid electrolyte interface(SEI)can be effective in improving the electrode kinetics.However,achieving fast charging using a simple and inexpensive strategy wi...Changes to the microstructure of a hard carbon(HC)and its solid electrolyte interface(SEI)can be effective in improving the electrode kinetics.However,achieving fast charging using a simple and inexpensive strategy without sacrificing its initial Coulombic efficiency remains a challenge in sodium ion batteries.A simple liquid-phase coating approach has been used to generate a pitch-derived soft carbon layer on the HC surface,and its effect on the porosity of HC and SEI chemistry has been studied.A variety of structural characterizations show a soft carbon coating can increase the defect and ultra-micropore contents.The increase in ultra-micropore comes from both the soft carbon coatings and the larger pores within the HC that are partially filled by pitch,which provides more Na+storage sites.In-situ FTIR/EIS and ex-situ XPS showed that the soft carbon coating induced the formation of thinner SEI that is richer in NaF from the electrolyte,which stabilized the interface and promoted the charge transfer process.As a result,the anode produced fastcharging(329.8 mAh g^(−1)at 30 mA g^(−1)and 198.6 mAh g^(−1)at 300 mA g^(−1))and had a better cycling performance(a high capacity retention of 81.4%after 100 cycles at 150 mA g^(−1)).This work reveals the critical role of coating layer in changing the pore structure,SEI chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced fast charging capability.展开更多
The Lunggar iron deposit belongs to the Bangong-Nujiang metallogenic belt and is located in central Lhasa on the Tibetan Plateau.In the Lunggar deposit,iron mineralization formed in the skarnization contact zone betwe...The Lunggar iron deposit belongs to the Bangong-Nujiang metallogenic belt and is located in central Lhasa on the Tibetan Plateau.In the Lunggar deposit,iron mineralization formed in the skarnization contact zone between the Early Cretaceous granodiorite and the late Permian Xiala Formation limestone.In this study,we achieved detailed zircon U-Pb-Hf isotopes and mineral chemistry for the Early Cretaceous granodiorite.Zircon U-Pb dating results indicate that the Early Cretaceous granodiorite emplaced at ca.119 Ma.Based on the trace elements in zircons and the mineral chemical composition of amphibole and biotite,the Early Cretaceous granodiorite was believed to form under condition of high temperature(>700°C),low pressure(100400 MPa),and relatively high oxygen fugacity(lgfO2)(13.6 to 13.9)and H2O content(4%8%).Zircon trace elements,Hf isotope and biotite chemistry collectively reveal that significant juvenile mantle-derived magmas contributed to the source of the granodiorite.The relatively high logfO2 and shallow magma chamber are beneficial for skarn iron mineralization,implying remarkable potential for further prospecting in the Lunggar iron deposit.展开更多
Over the past two years, significant progress in space chemistry has been made in China. The research fields include meteorites, pre-solar materials, science researches of the moon, effects of the space debris on spac...Over the past two years, significant progress in space chemistry has been made in China. The research fields include meteorites, pre-solar materials, science researches of the moon, effects of the space debris on space environment, and heterogeneity of the Earth. Chinese Lunar Exploration Project Some studies are also dedicated to one important space mission "Chinese Lunar Exploration Project". In this paper, the main achievements are outlined, and some concepts and hypotheses are briefly revised.展开更多
Over the past years Chinese space chemists have done much work on space chemistry and related disciplines, especially on the solar nebular evolution,meteorjtes, comparative planetology and the origin and evolution of ...Over the past years Chinese space chemists have done much work on space chemistry and related disciplines, especially on the solar nebular evolution,meteorjtes, comparative planetology and the origin and evolution of the Earth.In this paper, the authors outline the main achievements and briefly describe some new views and hypotheses.展开更多
The chemistry of subsurface water bodies is difficult to understand unless precipitation chemistry and atmospheric processes are taken into consideration. Limited pioneer work has been carried out on considering preci...The chemistry of subsurface water bodies is difficult to understand unless precipitation chemistry and atmospheric processes are taken into consideration. Limited pioneer work has been carried out on considering precipitation chemistry.Polluted zone delineation is very much significant before the planning for any of the remedial measures.The dual contamination is a common problem noticed展开更多
Chemical records were recovered from snow pits samples collected over the two transects (south\|north transect and southeast\|northwest transect) of the Qinghai—Tibetan plateau. It shows that the mean concentration o...Chemical records were recovered from snow pits samples collected over the two transects (south\|north transect and southeast\|northwest transect) of the Qinghai—Tibetan plateau. It shows that the mean concentration of the major ions over the south regions of Mt. Tanggula is lower than that of the north regions. The flux of major ions over north plateau is over 3 times higher than the south. The cloudy atmosphere of the north plateau is mainly contributed to the local input of dust, while in the south plateau, sea salt ions transported by Indian monsoon is considerable. The continental dust transportation from the north and the marine aerosol transportation from the south reach an approximately equilibrium around Mt. Tanggula regions. Stable oxygen isotopic ratios ( δ 18 O) in precipitation from the south\|north transect shows that, over the north plateau, δ 18 O is positively correlated with temperature, while over south of the plateau the correlation becomes weak and δ 18 O is more correlated with the amount of precipitation.展开更多
The Neoproterozoic Riviera W-REE-Mo deposit is one of the largest unmined tungsten resources in the world and is associated with pervasively altered A-type granites of the Neoproterozoic Cape Granite Suite Western Cap...The Neoproterozoic Riviera W-REE-Mo deposit is one of the largest unmined tungsten resources in the world and is associated with pervasively altered A-type granites of the Neoproterozoic Cape Granite Suite Western Cape, South Africa. The present study investigated the mineral chemistry of scheelite, the principal ore mineral with the aim to record the variation of solid solution molybdenum for geometallurgical purposes and also as an indicator of changing redox conditions of the mineralizing hydrothermal fluids. Methodology included UV-fluorescence studies and micro-analyses by LA-ICP-MS. Results have shown that at least four phases of scheelite are hosted by the endoskarn zone, potassic alteration zone and various quartz-carbonate veins. This reflects hydrothermal fluid evolution from early stage reduced to late stage, vein associated and more oxidized. The molybdenum content of the dominant early phase scheelite is low and renders the deposit amenable to low penalty mineral recovery.展开更多
Reduced graphene oxide(RGO) sheets with varied contents and types of oxygenated groups were synthesized by Hummers treatment of natural graphite powders followed by different nontoxic and mild reduction methods, which...Reduced graphene oxide(RGO) sheets with varied contents and types of oxygenated groups were synthesized by Hummers treatment of natural graphite powders followed by different nontoxic and mild reduction methods, which include thermal and chemical reduction with ethylene glycol, KOH and Fe powder. The changes in microstructure and surface chemistry of RGOs were extensively characterized by SEM, TEM, AFM, XRD, XPS and Raman spectrum. The results show that significant exfoliation occurs during oxidation and is retained in reduction processes, along with the formation of curled wavy morphology. Compared with large d spacing(0.852 nm) of graphene oxide(GO), the(002) plane distance decreases to 0.358-0.384 nm of RGOs, indicating efficient tuning of surface functionalities through mild reduction methods. The ID/IG ratio of RGOs is about 1.0-1.15, indicating that reconstructed sp^2 domains have smaller sizes and larger quantity. The content of sp^2 bonded C in GO(36.93%, molar fraction) increases to 45.48%-72.92%(molar fraction) in RGOs, along with a drastic decrease in hydroxyl and epoxy and minor changes in carbonyl and carboxyl. Thermal reduction or chemical reduction produces RGOs with residual functionalities, which may render different chemical activity and is desirable in various applications.展开更多
The pyrolysis of 5-HMF was investigated using density functional theory methods at B3LYP/6-31 G++(d, p) level. Two possible pyrolytic pathways were proposed and full optimization of the energy gradient for the structu...The pyrolysis of 5-HMF was investigated using density functional theory methods at B3LYP/6-31 G++(d, p) level. Two possible pyrolytic pathways were proposed and full optimization of the energy gradient for the structures of reactants, products, intermediates and transition states of various reactions was implemented. The standard kinetic parameters in each reaction pathway were calculated and the formation and evolution mechanism of main pyrolysis products were analyzed. Bond dissociation energies calculation results show that the bond dissociation energy of CH_3—OH of 5-HMF is the lowest and the order of all kinds of bond dissociation energy is CH_3—OH<C—H<CH_3 OH—C_(aromatic)<CHO—C_(aromatic)<C_(aromatic)—H. In pathway(1), the energy barrier of furfural is 322.8 kJ/mol, the energy barrier of 2-furfuryl alcohol is 375.4 kJ/mol; the energy barrier of furan-2,5-dicarbaldehyde is 496.1 kJ/mol; the energy barrier of 5-methyl furfural is 375.8 kJ/mol, and the energy barrier of 2-methyl furan is 375.8 kJ/mol. In pathway(2), the activation energy required for open-loop with H_2O is higher.展开更多
The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and rev...The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and reviews written by faculty members,researchers and postgraduates in universities,colleges and research institutes all over China and overseas.展开更多
The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and rev...The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and reviews written by faculty members,researchers and postgraduates in universities,colleges and research institutes all over China and overseas.It reports the latest and the most creative results of important fundamental research in all aspects of chemistry and of developments with significant consequences across sub-disciplines.This journal is sponsored by Jilin University and mandated by the Ministry of Education of P.R.China.展开更多
Food Science and Human Wellness(FSHW ISSN:2213-4530,CN 10-1750/TS)publishes original research papers demonstrating the latest advancement of multidisci-plinary subjects related to food science and human health.Topics ...Food Science and Human Wellness(FSHW ISSN:2213-4530,CN 10-1750/TS)publishes original research papers demonstrating the latest advancement of multidisci-plinary subjects related to food science and human health.Topics may include but not limited to:nutriology,bio-chemistry,microbiology,immunology and toxicology.展开更多
Food Science and Human Wellness(FSHW ISSN:2213-4530,CN 10-1750/TS)publishes original research papers demonstrating the latest advancement of multidisci-plinary subjects related to food science and human health.Topics ...Food Science and Human Wellness(FSHW ISSN:2213-4530,CN 10-1750/TS)publishes original research papers demonstrating the latest advancement of multidisci-plinary subjects related to food science and human health.Topics may include but not limited to:nutriology,bio-chemistry,microbiology,immunology and toxicology.展开更多
The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and rev...The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and reviews written by faculty members,researchers and postgraduates in universities,colleges and research institutes all over China and overseas.It reports the latest and the most creative results of important fundamental research in all aspects of chemistry and of developments with significant consequences across sub-disciplines.This journal is sponsored by Jilin University and mandated by the Ministry of Education of P.R.China.展开更多
Food Science and Human Wellness(FSHW ISSN:2213-4530,CN 10-1750/TS)publishes original research papers demonstrating the latest advancement of multidisci-plinary subjects related to food science and human health.Topics ...Food Science and Human Wellness(FSHW ISSN:2213-4530,CN 10-1750/TS)publishes original research papers demonstrating the latest advancement of multidisci-plinary subjects related to food science and human health.Topics may include but not limited to:nutriology,bio-chemistry,microbiology,immunology and toxicology.展开更多
Food Science and Human Wellness(FSHW ISSN:2213-4530,CN 10-1750/TS)publishes original research papers demonstrating the latest advancement of multidisci-plinary subjects related to food science and human health..Topics...Food Science and Human Wellness(FSHW ISSN:2213-4530,CN 10-1750/TS)publishes original research papers demonstrating the latest advancement of multidisci-plinary subjects related to food science and human health..Topics may include but not limited to:nutriology,bio-chemistry,microbiology,immunology and toxicology.展开更多
基金National Key Research and Development Program of China(2022YFE0206300)National Natural Science Foundation of China(U21A2081,22075074,22209047)+2 种基金Guangdong Basic and Applied Basic Research Foundation(2024A1515011620)Hunan Provincial Natural Science Foundation of China(2024JJ5068)Foundation of Yuelushan Center for Industrial Innovation(2023YCII0119)。
文摘Changes to the microstructure of a hard carbon(HC)and its solid electrolyte interface(SEI)can be effective in improving the electrode kinetics.However,achieving fast charging using a simple and inexpensive strategy without sacrificing its initial Coulombic efficiency remains a challenge in sodium ion batteries.A simple liquid-phase coating approach has been used to generate a pitch-derived soft carbon layer on the HC surface,and its effect on the porosity of HC and SEI chemistry has been studied.A variety of structural characterizations show a soft carbon coating can increase the defect and ultra-micropore contents.The increase in ultra-micropore comes from both the soft carbon coatings and the larger pores within the HC that are partially filled by pitch,which provides more Na+storage sites.In-situ FTIR/EIS and ex-situ XPS showed that the soft carbon coating induced the formation of thinner SEI that is richer in NaF from the electrolyte,which stabilized the interface and promoted the charge transfer process.As a result,the anode produced fastcharging(329.8 mAh g^(−1)at 30 mA g^(−1)and 198.6 mAh g^(−1)at 300 mA g^(−1))and had a better cycling performance(a high capacity retention of 81.4%after 100 cycles at 150 mA g^(−1)).This work reveals the critical role of coating layer in changing the pore structure,SEI chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced fast charging capability.
基金Project(2018YSJS14)supported by the Open Research Fund Program of Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University),Ministry of Education,China
文摘The Lunggar iron deposit belongs to the Bangong-Nujiang metallogenic belt and is located in central Lhasa on the Tibetan Plateau.In the Lunggar deposit,iron mineralization formed in the skarnization contact zone between the Early Cretaceous granodiorite and the late Permian Xiala Formation limestone.In this study,we achieved detailed zircon U-Pb-Hf isotopes and mineral chemistry for the Early Cretaceous granodiorite.Zircon U-Pb dating results indicate that the Early Cretaceous granodiorite emplaced at ca.119 Ma.Based on the trace elements in zircons and the mineral chemical composition of amphibole and biotite,the Early Cretaceous granodiorite was believed to form under condition of high temperature(>700°C),low pressure(100400 MPa),and relatively high oxygen fugacity(lgfO2)(13.6 to 13.9)and H2O content(4%8%).Zircon trace elements,Hf isotope and biotite chemistry collectively reveal that significant juvenile mantle-derived magmas contributed to the source of the granodiorite.The relatively high logfO2 and shallow magma chamber are beneficial for skarn iron mineralization,implying remarkable potential for further prospecting in the Lunggar iron deposit.
文摘Over the past two years, significant progress in space chemistry has been made in China. The research fields include meteorites, pre-solar materials, science researches of the moon, effects of the space debris on space environment, and heterogeneity of the Earth. Chinese Lunar Exploration Project Some studies are also dedicated to one important space mission "Chinese Lunar Exploration Project". In this paper, the main achievements are outlined, and some concepts and hypotheses are briefly revised.
文摘Over the past years Chinese space chemists have done much work on space chemistry and related disciplines, especially on the solar nebular evolution,meteorjtes, comparative planetology and the origin and evolution of the Earth.In this paper, the authors outline the main achievements and briefly describe some new views and hypotheses.
文摘The chemistry of subsurface water bodies is difficult to understand unless precipitation chemistry and atmospheric processes are taken into consideration. Limited pioneer work has been carried out on considering precipitation chemistry.Polluted zone delineation is very much significant before the planning for any of the remedial measures.The dual contamination is a common problem noticed
文摘Chemical records were recovered from snow pits samples collected over the two transects (south\|north transect and southeast\|northwest transect) of the Qinghai—Tibetan plateau. It shows that the mean concentration of the major ions over the south regions of Mt. Tanggula is lower than that of the north regions. The flux of major ions over north plateau is over 3 times higher than the south. The cloudy atmosphere of the north plateau is mainly contributed to the local input of dust, while in the south plateau, sea salt ions transported by Indian monsoon is considerable. The continental dust transportation from the north and the marine aerosol transportation from the south reach an approximately equilibrium around Mt. Tanggula regions. Stable oxygen isotopic ratios ( δ 18 O) in precipitation from the south\|north transect shows that, over the north plateau, δ 18 O is positively correlated with temperature, while over south of the plateau the correlation becomes weak and δ 18 O is more correlated with the amount of precipitation.
文摘The Neoproterozoic Riviera W-REE-Mo deposit is one of the largest unmined tungsten resources in the world and is associated with pervasively altered A-type granites of the Neoproterozoic Cape Granite Suite Western Cape, South Africa. The present study investigated the mineral chemistry of scheelite, the principal ore mineral with the aim to record the variation of solid solution molybdenum for geometallurgical purposes and also as an indicator of changing redox conditions of the mineralizing hydrothermal fluids. Methodology included UV-fluorescence studies and micro-analyses by LA-ICP-MS. Results have shown that at least four phases of scheelite are hosted by the endoskarn zone, potassic alteration zone and various quartz-carbonate veins. This reflects hydrothermal fluid evolution from early stage reduced to late stage, vein associated and more oxidized. The molybdenum content of the dominant early phase scheelite is low and renders the deposit amenable to low penalty mineral recovery.
基金Project(51274248)supported by the National Natural Science Foundation of ChinaProjects(2015DFR50580,2013DFA31440)supported by the International Scientific and Technological Cooperation Program of China
文摘Reduced graphene oxide(RGO) sheets with varied contents and types of oxygenated groups were synthesized by Hummers treatment of natural graphite powders followed by different nontoxic and mild reduction methods, which include thermal and chemical reduction with ethylene glycol, KOH and Fe powder. The changes in microstructure and surface chemistry of RGOs were extensively characterized by SEM, TEM, AFM, XRD, XPS and Raman spectrum. The results show that significant exfoliation occurs during oxidation and is retained in reduction processes, along with the formation of curled wavy morphology. Compared with large d spacing(0.852 nm) of graphene oxide(GO), the(002) plane distance decreases to 0.358-0.384 nm of RGOs, indicating efficient tuning of surface functionalities through mild reduction methods. The ID/IG ratio of RGOs is about 1.0-1.15, indicating that reconstructed sp^2 domains have smaller sizes and larger quantity. The content of sp^2 bonded C in GO(36.93%, molar fraction) increases to 45.48%-72.92%(molar fraction) in RGOs, along with a drastic decrease in hydroxyl and epoxy and minor changes in carbonyl and carboxyl. Thermal reduction or chemical reduction produces RGOs with residual functionalities, which may render different chemical activity and is desirable in various applications.
基金Project(51276023)supported by the National Natural Science Foundation of China
文摘The pyrolysis of 5-HMF was investigated using density functional theory methods at B3LYP/6-31 G++(d, p) level. Two possible pyrolytic pathways were proposed and full optimization of the energy gradient for the structures of reactants, products, intermediates and transition states of various reactions was implemented. The standard kinetic parameters in each reaction pathway were calculated and the formation and evolution mechanism of main pyrolysis products were analyzed. Bond dissociation energies calculation results show that the bond dissociation energy of CH_3—OH of 5-HMF is the lowest and the order of all kinds of bond dissociation energy is CH_3—OH<C—H<CH_3 OH—C_(aromatic)<CHO—C_(aromatic)<C_(aromatic)—H. In pathway(1), the energy barrier of furfural is 322.8 kJ/mol, the energy barrier of 2-furfuryl alcohol is 375.4 kJ/mol; the energy barrier of furan-2,5-dicarbaldehyde is 496.1 kJ/mol; the energy barrier of 5-methyl furfural is 375.8 kJ/mol, and the energy barrier of 2-methyl furan is 375.8 kJ/mol. In pathway(2), the activation energy required for open-loop with H_2O is higher.
文摘The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and reviews written by faculty members,researchers and postgraduates in universities,colleges and research institutes all over China and overseas.
文摘The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and reviews written by faculty members,researchers and postgraduates in universities,colleges and research institutes all over China and overseas.It reports the latest and the most creative results of important fundamental research in all aspects of chemistry and of developments with significant consequences across sub-disciplines.This journal is sponsored by Jilin University and mandated by the Ministry of Education of P.R.China.
文摘Food Science and Human Wellness(FSHW ISSN:2213-4530,CN 10-1750/TS)publishes original research papers demonstrating the latest advancement of multidisci-plinary subjects related to food science and human health.Topics may include but not limited to:nutriology,bio-chemistry,microbiology,immunology and toxicology.
文摘Food Science and Human Wellness(FSHW ISSN:2213-4530,CN 10-1750/TS)publishes original research papers demonstrating the latest advancement of multidisci-plinary subjects related to food science and human health.Topics may include but not limited to:nutriology,bio-chemistry,microbiology,immunology and toxicology.
文摘The journal Chemical Research in Chinese Universities is a comprehensive academic journal in the field of chemistry,published bimonthly since 1984.The journal publishes research articles,letters/communications and reviews written by faculty members,researchers and postgraduates in universities,colleges and research institutes all over China and overseas.It reports the latest and the most creative results of important fundamental research in all aspects of chemistry and of developments with significant consequences across sub-disciplines.This journal is sponsored by Jilin University and mandated by the Ministry of Education of P.R.China.
文摘Food Science and Human Wellness(FSHW ISSN:2213-4530,CN 10-1750/TS)publishes original research papers demonstrating the latest advancement of multidisci-plinary subjects related to food science and human health.Topics may include but not limited to:nutriology,bio-chemistry,microbiology,immunology and toxicology.
文摘Food Science and Human Wellness(FSHW ISSN:2213-4530,CN 10-1750/TS)publishes original research papers demonstrating the latest advancement of multidisci-plinary subjects related to food science and human health..Topics may include but not limited to:nutriology,bio-chemistry,microbiology,immunology and toxicology.
