The Hujiayu Cu deposit,representative of the ＂HuBi-type＂ Cu deposits in the Zhongtiao Mountains district in the southern edge of the North China Craton,is primarily hosted in graphitebearing schists and carbonate ro...The Hujiayu Cu deposit,representative of the ＂HuBi-type＂ Cu deposits in the Zhongtiao Mountains district in the southern edge of the North China Craton,is primarily hosted in graphitebearing schists and carbonate rocks.The ore minerals comprise mainly chalcopyrite,with minor sphalerite,siegenite[（Co,Ni）_3S_4],and clausthalite[Pb（S,Se）].The gangue minerals are mainly quartz and dolomite,with minor albite.Four fluid inclusion types were recognized in the chalcopyrite-pyrite-dolomite-quartz veins,including CO_2-rich inclusions（type Ⅰ）,low-salinity,liquid-dominated,biphase aqueous inclusions（type Ⅱ）,solid-bearing aqueous inclusions（type Ⅲ）,and solid-bearing aqueous-carbonic inclusions（type Ⅳ）.Type I inclusion can be further divided into two sub-types,i.e.,monophase CO_2 inclusions（type Ⅰa） and biphase CO_2-rich inclusions（with a visible aqueous phase）,and type Ⅲ inclusion is divided into a subtype with a halite daughter mineral（type Ⅲa） and a subtype with multiple solids（type Ⅲb）.Various fluid inclusion assemblages（FIAs） were identified through petrographic observations,and were classified into four groups.The group-1 FIA,consisting of monophase CO_2 inclusions（type Ⅰa）,homogenized into the liquid phase in a large range of temperatures from-1 to 28℃,suggesting post-entrapment modification.The group-2 FIA consists of type Ⅰb,Ⅲb and Ⅳ inclusions,and is interpreted to reflect fluid immiscibility.The group-3 FIA comprises type Ⅱ and Ⅲa inclusions,and the group-4FIA consists of type Ⅱ inclusions with consistent phase ratios.The group-1 and group-2 FIAs are interpreted to be entrapped during mineralization,whereas group-3 and group-4 FIAs probably represent the post-mineralization fluids.The solid CO_2 melting temperatures range from-60.6 to56.6℃ and from-66.0 to-63.4℃ for type Ⅰa and type Ⅳ inclusions,respectively.The homogenization temperatures for type Ⅱ inclusions range from 132 to 170℃ for group-3 FIAs and115 to 219℃ for group-4 FIAs.The halite melting temperatures range from 530 to 562℃ for typeⅢ b and Ⅳ inclusions,whereas those for type Ⅲa inclusions range from 198 to 398℃.Laser Raman and SEM-EDS results show that the gas species in fluid inclusions are mainly CO_2 with minor CH_4,and the solids are dominated by calcite and halite.The calcite in the hosting marble and dolomite in the hydrothermal veins have δ^（13）C_（V-pdb） values of-0.2 to 1.2‰ and-1.2 to-6.3‰,and δ^（18）O_（v-smow） values of 14.0 to 20.8 ‰ and 13.2 to 14.3‰,respectively.The fluid inclusion and carbon-oxygen isotope data suggest that the ore-forming fluids were probably derived from metamorphic fluids,which had reacted with organic matter in sedimentary rocks or graphite and undergone phase separation at 1.4-1.8 kbar and 230-240℃,after peak metamorphism.It is proposed that the Hujiayu Cu deposit consists of two mineralization stages.The early stage mineralization,characterized by disseminated and veinlet copper sulfides,probably took place in an environment similar to sediment-hosted stratiform copper mineralization.Ore minerals formed in this precursor mineralization stage were remobilized and enriched in the late metamorphic hydrothermal stage,leading to the formation of thick quartz-dolomite-sulfides veins.展开更多
REE-fluorocarbonates as major REE minerals in the Bayan Obo deposit, the largestREE deposit in the world, were analyzed for their stable isotopic compositions. The δ13C andδ18O values of huanghoite, cebaite and bast...REE-fluorocarbonates as major REE minerals in the Bayan Obo deposit, the largestREE deposit in the world, were analyzed for their stable isotopic compositions. The δ13C andδ18O values of huanghoite, cebaite and bastnaesite from late-stage veins vary in the ranges of -7. 8 - - 4. 0‰ and 6. 7 - 9. 4‰ respectively. These data are relatively similar tO those ofbastnaesites from banded ores: δ13C - 5. 6 - - 5. 2‰ and δ18O 3. 6 - 5. 5‰ The REEfluorocarbonates from both late-stage veins and banded ores are characterized by lower δ13C andδ18O values, especially the δ18O values of bastnaesites from banded ores. Compared with them,the disseminated bastnaesits the dolomite-type ores possess rather high δ13C and δ18O values, i.e., - 2. 1 - - O. 4‰ and 8. 6 - 12. 9‰ respectively. The high values are typical of thesedimentary host dolomite rocks as well as of the dolomite-type ores. The carbon and oxygenisotopic characteristics of REE fluorocarbonate minerals provide new evidence for the hypothesison the origin of Bayan Obo deposit-epigenetic hydrothermal metasomatism.展开更多
RuO2 nanoparticles supported on multi-walled carbon nanotubes（CNTs） functionalized with oxygen（OCNTs） and nitrogen（NCNTs） were employed for the oxygen evolution reaction（OER） in 0.1 M KOH.The catalysts were sy...RuO2 nanoparticles supported on multi-walled carbon nanotubes（CNTs） functionalized with oxygen（OCNTs） and nitrogen（NCNTs） were employed for the oxygen evolution reaction（OER） in 0.1 M KOH.The catalysts were synthesized by metal-organic chemical vapor deposition using ruthenium carbonyl（Ru3（CO）（12）） as Ru precursor. The obtained RuO2/OCNT and RuO2/NCNT composites were characterized using TEM, H2-TPR, XRD and XPS in order probe structure–activity correlations, particularly, the effect of the different surface functional groups on the electrochemical OER performance. The electrocatalytic activity and stability of the catalysts with mean RuO2 particle sizes of 13–14 nm was evaluated by linear sweep voltammetry, cyclic voltammetry, and chronopotentiometry, showing that the generation of nitrogen-containing functional groups on CNTs was beneficial for both OER activity and stability. In the presence of RuO2, carbon corrosion was found to be significantly less severe.展开更多
The introduction of nitrogen heteroatoms into carbon materials is a facile and efficient strategy to regulate their reactivities and facilitate their potential applications in energy conversion and storage. However,mo...The introduction of nitrogen heteroatoms into carbon materials is a facile and efficient strategy to regulate their reactivities and facilitate their potential applications in energy conversion and storage. However,most of nitrogen heteroatoms are doped into the bulk phase of carbon without site selectivity, which significantly reduces the contacts of feedstocks with the active dopants in a conductive scaffold. Herein we proposed the chemical vapor deposition of a nitrogen-doped graphene skin on the 3D porous graphene framework and donated the carbon/carbon composite as surface N-doped grapheme（SNG）. In contrast with routine N-doped graphene framework（NGF） with bulk distribution of N heteroatoms, the SNG renders a high surface N content of 1.81 at%, enhanced electrical conductivity of 31 S cm^（-1）, a large surface area of 1531 m^2 g^（-1）, a low defect density with a low I_D/I_G ratio of 1.55 calculated from Raman spectrum, and a high oxidation peak of 532.7 ℃ in oxygen atmosphere. The selective distribution of N heteroatoms on the surface of SNG affords the effective exposure of active sites at the interfaces of the electrode/electrolyte, so that more N heteroatoms are able to contact with oxygen feedstocks in oxygen reduction reaction or serve as polysulfide anchoring sites to retard the shuttle of polysulfides in a lithium–sulfur battery. This work opens a fresh viewpoint on the manipulation of active site distribution in a conductive scaffolds for multi-electron redox reaction based energy conversion and storage.展开更多
From the studies of ore deposit geologic settings, sulfur i so topes, lead isotopes, carbon isotopes and oxygen isotopes, fluid inclusions and petrochemistry in this paper, the authors have drawn a conclusion that the...From the studies of ore deposit geologic settings, sulfur i so topes, lead isotopes, carbon isotopes and oxygen isotopes, fluid inclusions and petrochemistry in this paper, the authors have drawn a conclusion that the ore- forming hydrothermal solutions are the high-temperature magmatic hydrothermal s olutions for the gold ore deposit, and at the same time, the involvement of crus tal materials can not be ruled out. It is the first time that the authors have p roposed that the Laozuoshan gold-polymetallic ore deposit in Heilongjiang Prov ince was formed in the calc-alkaline series environment at the margin of an act ive continent.展开更多
Being stratiform or stratoid, the Huangbaishuwan witherite deposit at Ziyang and the Wenyuhe witherite-barite deposit at Zhushan occur in the lower Lower Cambrian siliceous rocks and the orebodies are remarkably contr...Being stratiform or stratoid, the Huangbaishuwan witherite deposit at Ziyang and the Wenyuhe witherite-barite deposit at Zhushan occur in the lower Lower Cambrian siliceous rocks and the orebodies are remarkably controlled by lithological character and petrography. Boron, carbon and oxygen isotopic studies of witherite, barytocalcite and calcite have shown that the car-bon, involved in the formation of these minerals, was derived mainly from hydrocarbons and bio-genetic gases resulting from degradation, polycondensation and dehydroxylation of bio-organic matter in sediments at the early stage of diagenesis; the boron was a mixture of boron in pore wa-ter and that released in the process of degradation of organic matter, with a minor amount of boron from cycling brines in the deep interior of the basin. Boron, carbon and oxygen isotopic studies unanimously demonstrated that witherite was precipitated in this sort of organic carbon-rich pore water medium during the early stage of diagenesis. Extensive occurrence of biodetritus and clastic texture in witherite ores strongly evidenced that Ba2+ was concentrated and settled down in the form of bio-barite on the seafloor as a result of biological processes, thereafter forming the initially enriched orebodies of barium deposits. Biological processes in seawater and early diagenesis in sediments are the major ore-forming mechanisms of witherite deposits in the region studied.展开更多
基金financed by Major State Basic Research Development Program(2012CB416605)Natural Science Foundation of China(41402083)
文摘The Hujiayu Cu deposit,representative of the ＂HuBi-type＂ Cu deposits in the Zhongtiao Mountains district in the southern edge of the North China Craton,is primarily hosted in graphitebearing schists and carbonate rocks.The ore minerals comprise mainly chalcopyrite,with minor sphalerite,siegenite[（Co,Ni）_3S_4],and clausthalite[Pb（S,Se）].The gangue minerals are mainly quartz and dolomite,with minor albite.Four fluid inclusion types were recognized in the chalcopyrite-pyrite-dolomite-quartz veins,including CO_2-rich inclusions（type Ⅰ）,low-salinity,liquid-dominated,biphase aqueous inclusions（type Ⅱ）,solid-bearing aqueous inclusions（type Ⅲ）,and solid-bearing aqueous-carbonic inclusions（type Ⅳ）.Type I inclusion can be further divided into two sub-types,i.e.,monophase CO_2 inclusions（type Ⅰa） and biphase CO_2-rich inclusions（with a visible aqueous phase）,and type Ⅲ inclusion is divided into a subtype with a halite daughter mineral（type Ⅲa） and a subtype with multiple solids（type Ⅲb）.Various fluid inclusion assemblages（FIAs） were identified through petrographic observations,and were classified into four groups.The group-1 FIA,consisting of monophase CO_2 inclusions（type Ⅰa）,homogenized into the liquid phase in a large range of temperatures from-1 to 28℃,suggesting post-entrapment modification.The group-2 FIA consists of type Ⅰb,Ⅲb and Ⅳ inclusions,and is interpreted to reflect fluid immiscibility.The group-3 FIA comprises type Ⅱ and Ⅲa inclusions,and the group-4FIA consists of type Ⅱ inclusions with consistent phase ratios.The group-1 and group-2 FIAs are interpreted to be entrapped during mineralization,whereas group-3 and group-4 FIAs probably represent the post-mineralization fluids.The solid CO_2 melting temperatures range from-60.6 to56.6℃ and from-66.0 to-63.4℃ for type Ⅰa and type Ⅳ inclusions,respectively.The homogenization temperatures for type Ⅱ inclusions range from 132 to 170℃ for group-3 FIAs and115 to 219℃ for group-4 FIAs.The halite melting temperatures range from 530 to 562℃ for typeⅢ b and Ⅳ inclusions,whereas those for type Ⅲa inclusions range from 198 to 398℃.Laser Raman and SEM-EDS results show that the gas species in fluid inclusions are mainly CO_2 with minor CH_4,and the solids are dominated by calcite and halite.The calcite in the hosting marble and dolomite in the hydrothermal veins have δ^（13）C_（V-pdb） values of-0.2 to 1.2‰ and-1.2 to-6.3‰,and δ^（18）O_（v-smow） values of 14.0 to 20.8 ‰ and 13.2 to 14.3‰,respectively.The fluid inclusion and carbon-oxygen isotope data suggest that the ore-forming fluids were probably derived from metamorphic fluids,which had reacted with organic matter in sedimentary rocks or graphite and undergone phase separation at 1.4-1.8 kbar and 230-240℃,after peak metamorphism.It is proposed that the Hujiayu Cu deposit consists of two mineralization stages.The early stage mineralization,characterized by disseminated and veinlet copper sulfides,probably took place in an environment similar to sediment-hosted stratiform copper mineralization.Ore minerals formed in this precursor mineralization stage were remobilized and enriched in the late metamorphic hydrothermal stage,leading to the formation of thick quartz-dolomite-sulfides veins.
文摘REE-fluorocarbonates as major REE minerals in the Bayan Obo deposit, the largestREE deposit in the world, were analyzed for their stable isotopic compositions. The δ13C andδ18O values of huanghoite, cebaite and bastnaesite from late-stage veins vary in the ranges of -7. 8 - - 4. 0‰ and 6. 7 - 9. 4‰ respectively. These data are relatively similar tO those ofbastnaesites from banded ores: δ13C - 5. 6 - - 5. 2‰ and δ18O 3. 6 - 5. 5‰ The REEfluorocarbonates from both late-stage veins and banded ores are characterized by lower δ13C andδ18O values, especially the δ18O values of bastnaesites from banded ores. Compared with them,the disseminated bastnaesits the dolomite-type ores possess rather high δ13C and δ18O values, i.e., - 2. 1 - - O. 4‰ and 8. 6 - 12. 9‰ respectively. The high values are typical of thesedimentary host dolomite rocks as well as of the dolomite-type ores. The carbon and oxygenisotopic characteristics of REE fluorocarbonate minerals provide new evidence for the hypothesison the origin of Bayan Obo deposit-epigenetic hydrothermal metasomatism.
基金the IMPRS-Sur Mat of the Max Planck Society for a research grant
文摘RuO2 nanoparticles supported on multi-walled carbon nanotubes（CNTs） functionalized with oxygen（OCNTs） and nitrogen（NCNTs） were employed for the oxygen evolution reaction（OER） in 0.1 M KOH.The catalysts were synthesized by metal-organic chemical vapor deposition using ruthenium carbonyl（Ru3（CO）（12）） as Ru precursor. The obtained RuO2/OCNT and RuO2/NCNT composites were characterized using TEM, H2-TPR, XRD and XPS in order probe structure–activity correlations, particularly, the effect of the different surface functional groups on the electrochemical OER performance. The electrocatalytic activity and stability of the catalysts with mean RuO2 particle sizes of 13–14 nm was evaluated by linear sweep voltammetry, cyclic voltammetry, and chronopotentiometry, showing that the generation of nitrogen-containing functional groups on CNTs was beneficial for both OER activity and stability. In the presence of RuO2, carbon corrosion was found to be significantly less severe.
基金supported by the National Key Research and Development Program(2016YFA0202500 and 2016YFA0200102)the Natural Scientific Foundation of China(21776019)
文摘The introduction of nitrogen heteroatoms into carbon materials is a facile and efficient strategy to regulate their reactivities and facilitate their potential applications in energy conversion and storage. However,most of nitrogen heteroatoms are doped into the bulk phase of carbon without site selectivity, which significantly reduces the contacts of feedstocks with the active dopants in a conductive scaffold. Herein we proposed the chemical vapor deposition of a nitrogen-doped graphene skin on the 3D porous graphene framework and donated the carbon/carbon composite as surface N-doped grapheme（SNG）. In contrast with routine N-doped graphene framework（NGF） with bulk distribution of N heteroatoms, the SNG renders a high surface N content of 1.81 at%, enhanced electrical conductivity of 31 S cm^（-1）, a large surface area of 1531 m^2 g^（-1）, a low defect density with a low I_D/I_G ratio of 1.55 calculated from Raman spectrum, and a high oxidation peak of 532.7 ℃ in oxygen atmosphere. The selective distribution of N heteroatoms on the surface of SNG affords the effective exposure of active sites at the interfaces of the electrode/electrolyte, so that more N heteroatoms are able to contact with oxygen feedstocks in oxygen reduction reaction or serve as polysulfide anchoring sites to retard the shuttle of polysulfides in a lithium–sulfur battery. This work opens a fresh viewpoint on the manipulation of active site distribution in a conductive scaffolds for multi-electron redox reaction based energy conversion and storage.
文摘From the studies of ore deposit geologic settings, sulfur i so topes, lead isotopes, carbon isotopes and oxygen isotopes, fluid inclusions and petrochemistry in this paper, the authors have drawn a conclusion that the ore- forming hydrothermal solutions are the high-temperature magmatic hydrothermal s olutions for the gold ore deposit, and at the same time, the involvement of crus tal materials can not be ruled out. It is the first time that the authors have p roposed that the Laozuoshan gold-polymetallic ore deposit in Heilongjiang Prov ince was formed in the calc-alkaline series environment at the margin of an act ive continent.
基金the“97’One Hundred Qualified Personnel Program”sponsored the Chinese Academy of Sciences+2 种基金the Climbing Program sponsored by Ministry of Science and Technology(Grant No.95-yu-39)the State Science Foundation for Outstanding Young Scientis ts(Grant No.49625304) the State Key Basic Research and Development Plan(Grant No.G1999045708).
文摘Being stratiform or stratoid, the Huangbaishuwan witherite deposit at Ziyang and the Wenyuhe witherite-barite deposit at Zhushan occur in the lower Lower Cambrian siliceous rocks and the orebodies are remarkably controlled by lithological character and petrography. Boron, carbon and oxygen isotopic studies of witherite, barytocalcite and calcite have shown that the car-bon, involved in the formation of these minerals, was derived mainly from hydrocarbons and bio-genetic gases resulting from degradation, polycondensation and dehydroxylation of bio-organic matter in sediments at the early stage of diagenesis; the boron was a mixture of boron in pore wa-ter and that released in the process of degradation of organic matter, with a minor amount of boron from cycling brines in the deep interior of the basin. Boron, carbon and oxygen isotopic studies unanimously demonstrated that witherite was precipitated in this sort of organic carbon-rich pore water medium during the early stage of diagenesis. Extensive occurrence of biodetritus and clastic texture in witherite ores strongly evidenced that Ba2+ was concentrated and settled down in the form of bio-barite on the seafloor as a result of biological processes, thereafter forming the initially enriched orebodies of barium deposits. Biological processes in seawater and early diagenesis in sediments are the major ore-forming mechanisms of witherite deposits in the region studied.
