The Phapon gold deposit, located in northern Laos, is a unique large-scale gold deposit in Luang Prabang-Loei metallogenic belt. It is hosted in the Lower Permian limestone and controlled by a NE-trending ductile-brit...The Phapon gold deposit, located in northern Laos, is a unique large-scale gold deposit in Luang Prabang-Loei metallogenic belt. It is hosted in the Lower Permian limestone and controlled by a NE-trending ductile-brittle fault system. There are three types of primary ore including auriferous calcite vein type, disseminated type, and breccia type, and the first two are important in the Phapon gold deposit. Based on fluid inclusion petrography and microthermometry, three types of primary fluid inclusions including type 1 liquid-rich aqueous, type 2 vapor-rich aqueous and type 3 daughter mineralbearing aqueous were identified in hydrothermal calcite grains. The ore-forming fluids are normally homogeneous, as indicated by the widespread type 1 inclusions with identical composition. The coexistence of type 1 and type 2 inclusions, showing similar final homogenization temperature but different compositions, indicate that fluid immiscibility did locally take place in both two types of ores. The results of microthermometry and H-O isotopes geochemistry indicate that there are little differences on ore-fluid geochemistry between the auriferous calcite vein-type and disseminated type ores. The oreforming fluids are characterized by medium-low temperatures(157–268 oC) and low salinity(1.6 wt.%–9.9 wt.% NaCl eq.). It is likely to have a metamorphic-dominant mixed source, which could be associated with dehydration and decarbonisation of Lower Permian limestone and Middle–Upper Triassic sandstones during the dynamic metamorphism. The fluid-wallrock interaction played a major role, and the locally occurred fluid-immiscible processes played a subordinate role in gold precipitation. Combined with the regional and ore deposit geology, and ore-fluid geochemistry, we suggest that the Phapon gold deposit is best considered to be a member of the epizonal orogenic deposit class.展开更多
An integrated study of zircon U-Pb geochronology and petrochemistry, together with zircon Lu-Hf isotopes, has been carried out on the basaltic-andesitic tuff and volcanic breccia from the Nam Hang Formation and andesi...An integrated study of zircon U-Pb geochronology and petrochemistry, together with zircon Lu-Hf isotopes, has been carried out on the basaltic-andesitic tuff and volcanic breccia from the Nam Hang Formation and andesitic tuff from the Muang-Nan Formation in the Xaignabouli area, which had been mapped as the Permian–Early Triassic on the 1 : 1 000 000 geological map or Late Carboniferous on the 1 : 200 000 geological maps. Zircon U-Pb dating of three samples yielded weighted mean ages of 235±2.6, 232±1.4 and 278±2.8 Ma, respectively, suggesting a Late Triassic origin for the Nam Hang Formation and an Early Permian origin for the Muang-Nan Formation. Geochemically, they are characterized by depletions in HFSEs(e.g., Nb, Ta, Ti) and high LILE/HFSE ratios, and they have positive zircon ε_(Hf)(t) values of 8.7–15.9, which exhibits the continental arc volcanic affinity and partial melting of subducting oceanic slab in the magma source. Combined with spatial occurrence of the volcanic rock and existing geochronological and geochemical data, we suggest that the Xaignabouli-Luang Prabang volcanic belt can be linked to the Loei-Phetchabun belt. The Permian–Triassic volcanic rocks in this belt might be a product of the Nan back-arc basin eastward subduction.展开更多
The Nan Suture and Sukhothai Arc Terrane are products of the eastward subduction of the Paleotethyan Ocean during the Late Carboniferous to Triassic.However,their footprints in northwestern Laos are poorly constrained...The Nan Suture and Sukhothai Arc Terrane are products of the eastward subduction of the Paleotethyan Ocean during the Late Carboniferous to Triassic.However,their footprints in northwestern Laos are poorly constrained.New geochronological and geochemical data presented in this study demonstrate a Late Permian origin for the andesitic rocks in the B.Xiengnou area rather than Late Triassic.The breccia-bearing andesitic tuff in the B.On ultramafic complex yield a zircon U-Pb age of 260±1.4 Ma,geochemically displaying a MORB-like signature.The andesitic tuff in the B.Kiophoulan-B.Houayhak belt gave the U-Pb age of 254±1.3 Ma,with arc-like geochemical affinity.By combining geochronological and geochemical data from the Nan Suture and Sukhothai Arc Terrane,the authors suggest that the andesitic rocks in the B.On ultramafic complex formed in a back-arc basin background,which connected the Jinghong and Nan back-arc basin during the Permian;while the andesitic tuff in the B.Kiophoulan-B.Houayhak belt erupted in the Sukhothai continental arc setting.展开更多
1.Objective Southeast Asia has a 3500 km tin metallogenic belt in the world,extending from southern Yunnan Province to Bangka,Indonesia.This region is also the world’s largest one regarding tin production,which accou...1.Objective Southeast Asia has a 3500 km tin metallogenic belt in the world,extending from southern Yunnan Province to Bangka,Indonesia.This region is also the world’s largest one regarding tin production,which accounts for 85%of historical tin production globally(Lehmann B,2021).Myanmar is one of the main tin producers within this region(33000 t in 2020)and has become the key supplier after China and Indonesia.Research on tin mineralization in Myanmar mostly focused on ore-related granites,for zircon geochronology,magma evolution,and tectonic settings(Mao W et al.,2020).展开更多
—With the increase of converter-based renewable energy generation connected into the power grid, the interaction between renewable energy and grid impedance has introduced lots of new issues, among which the sub-and ...—With the increase of converter-based renewable energy generation connected into the power grid, the interaction between renewable energy and grid impedance has introduced lots of new issues, among which the sub-and super-synchronous oscillation phenomenon makes a big concern. The linear active disturbance rejection control(LADRC) is a potential way to improve the damping characteristics of the grid-connected system, but the key factors and influencing mechanism on system stability are unknown. This paper establishes the equivalent impedance and coupling admittance models of a typical three-phase grid-connected converter. Then, the influence of the key factors such as the bandwidth of the LADRC and grid impedance on the stability and frequency coupling effect is assessed in detail. Finally, the theoretical analysis results are verified by simulations and experiments.展开更多
This study examines the impact of outward foreign direct investment(OFDI)on Chinese manufacturing firms'financialization and servitization.Using a difference-in-differences approach with propensity score matching,...This study examines the impact of outward foreign direct investment(OFDI)on Chinese manufacturing firms'financialization and servitization.Using a difference-in-differences approach with propensity score matching,we found that OFDI encouraged firms'financial and service activities.The effects of OFDI on financialization were stronger for firms specializing in short-term financial assets,operating in labor and technology-intensive sectors,investing overseas to pursue production,resources and markets there,and investing in non-OECD and Belt and Road Initiative(BRI)countries.Meanwhile,firms investing overseas were more likely to provide services at the sale or postsale stages.Outward foreign direct investment has also boosted the service activities of firms operating in the technology-intensive sector by investing overseas to seek resources and markets,as well as investing in non-OECD and BRI countries.Finally,OFDI partially influenced the extent of financialization and servitization of firms by affecting their profit-making ability.展开更多
Large-scale electrolysis of water to produce high-purity hydrogen is one of the effective ways to solve the energy crisis and environmental pollution problems.However,efficient,cheap and stable catalysts are one of th...Large-scale electrolysis of water to produce high-purity hydrogen is one of the effective ways to solve the energy crisis and environmental pollution problems.However,efficient,cheap and stable catalysts are one of the bottlenecks for industrial application in water splitting.Herein,a facile one-step hydrothermal process was applied to fabricate Mn-doped nickel ferrite nanosheets(Mn-NiFe_(2)O_(4))which shown a low overpotential of 200 mV at 50 mA·cm^(-2)and a small Tafel slope of 47 mV·dec^(-1),together with a prominent turnover frequency(TOF)value(0.14 s^(-1))and robust stability.The in-situ UV-vis spectroscopy unveiled the surface reconstruction to generate NiOOH as active sites during oxygen evolution reaction(OER).The excellent electrocatalytic activity of Mn-NiFe_(2)O_(4)is attributed to the vertically grown nanosheets for exposure more active sites,rich oxygen vacancies,and the hybridization between Ni 3d and O 2p orbitals caused by Mn doping.This work should provide a facile strategy by Mn-doping to simultaneously engineer oxygen vacancies and electronic structure for synergistically triggering oxygen evolution reaction.展开更多
Materials exhibiting persistently ultralong room-temperature phosphorescence(RTP)are capturing significant attention due to their long lifetimes,pronounced Stokes shifts,and efficient exciton utilization[1–3].These a...Materials exhibiting persistently ultralong room-temperature phosphorescence(RTP)are capturing significant attention due to their long lifetimes,pronounced Stokes shifts,and efficient exciton utilization[1–3].These attributes position RTP materials as ideal candidates for advanced applications in information security,data storage,light-emitting diodes,bioimaging[4–6].展开更多
The strategies including noncovalent macrocycle-confined supramolecular assembly and construction of rigid hydrogen-bond network have been verified as effective routes to brighten aqueous-phase room temperature phosph...The strategies including noncovalent macrocycle-confined supramolecular assembly and construction of rigid hydrogen-bond network have been verified as effective routes to brighten aqueous-phase room temperature phosphorescence.Molecule-based room-temperature phosphorescence(RTP)has attracted widespread attention in the fields of chemical sensors,optical anti-counterfeiting,information encoding and so on,due to unique characteristics of long excited-state lifetimes,large Stokes shifts and high signal-tonoise ratios[1,2].Currently,to obtain RTP with considerable efficiency and long lifetime,two brilliant strategies have been developed:one is the introduction of heavy atoms,which facilitates the spin-orbital coupling and intersystem crossing(ISC)from singlet to triplet states。展开更多
基金financially supported by the China Geological Survey Project (No. 121201010000150013)
文摘The Phapon gold deposit, located in northern Laos, is a unique large-scale gold deposit in Luang Prabang-Loei metallogenic belt. It is hosted in the Lower Permian limestone and controlled by a NE-trending ductile-brittle fault system. There are three types of primary ore including auriferous calcite vein type, disseminated type, and breccia type, and the first two are important in the Phapon gold deposit. Based on fluid inclusion petrography and microthermometry, three types of primary fluid inclusions including type 1 liquid-rich aqueous, type 2 vapor-rich aqueous and type 3 daughter mineralbearing aqueous were identified in hydrothermal calcite grains. The ore-forming fluids are normally homogeneous, as indicated by the widespread type 1 inclusions with identical composition. The coexistence of type 1 and type 2 inclusions, showing similar final homogenization temperature but different compositions, indicate that fluid immiscibility did locally take place in both two types of ores. The results of microthermometry and H-O isotopes geochemistry indicate that there are little differences on ore-fluid geochemistry between the auriferous calcite vein-type and disseminated type ores. The oreforming fluids are characterized by medium-low temperatures(157–268 oC) and low salinity(1.6 wt.%–9.9 wt.% NaCl eq.). It is likely to have a metamorphic-dominant mixed source, which could be associated with dehydration and decarbonisation of Lower Permian limestone and Middle–Upper Triassic sandstones during the dynamic metamorphism. The fluid-wallrock interaction played a major role, and the locally occurred fluid-immiscible processes played a subordinate role in gold precipitation. Combined with the regional and ore deposit geology, and ore-fluid geochemistry, we suggest that the Phapon gold deposit is best considered to be a member of the epizonal orogenic deposit class.
基金financially supported by the China Geological Survey (No. 121201010000150013)
文摘An integrated study of zircon U-Pb geochronology and petrochemistry, together with zircon Lu-Hf isotopes, has been carried out on the basaltic-andesitic tuff and volcanic breccia from the Nam Hang Formation and andesitic tuff from the Muang-Nan Formation in the Xaignabouli area, which had been mapped as the Permian–Early Triassic on the 1 : 1 000 000 geological map or Late Carboniferous on the 1 : 200 000 geological maps. Zircon U-Pb dating of three samples yielded weighted mean ages of 235±2.6, 232±1.4 and 278±2.8 Ma, respectively, suggesting a Late Triassic origin for the Nam Hang Formation and an Early Permian origin for the Muang-Nan Formation. Geochemically, they are characterized by depletions in HFSEs(e.g., Nb, Ta, Ti) and high LILE/HFSE ratios, and they have positive zircon ε_(Hf)(t) values of 8.7–15.9, which exhibits the continental arc volcanic affinity and partial melting of subducting oceanic slab in the magma source. Combined with spatial occurrence of the volcanic rock and existing geochronological and geochemical data, we suggest that the Xaignabouli-Luang Prabang volcanic belt can be linked to the Loei-Phetchabun belt. The Permian–Triassic volcanic rocks in this belt might be a product of the Nan back-arc basin eastward subduction.
基金This study is co-supported by the National Natural Science Foundation of China(41702087)the China Geological Survey(DD2019444)the China Scholarship Council(201908575026).
文摘The Nan Suture and Sukhothai Arc Terrane are products of the eastward subduction of the Paleotethyan Ocean during the Late Carboniferous to Triassic.However,their footprints in northwestern Laos are poorly constrained.New geochronological and geochemical data presented in this study demonstrate a Late Permian origin for the andesitic rocks in the B.Xiengnou area rather than Late Triassic.The breccia-bearing andesitic tuff in the B.On ultramafic complex yield a zircon U-Pb age of 260±1.4 Ma,geochemically displaying a MORB-like signature.The andesitic tuff in the B.Kiophoulan-B.Houayhak belt gave the U-Pb age of 254±1.3 Ma,with arc-like geochemical affinity.By combining geochronological and geochemical data from the Nan Suture and Sukhothai Arc Terrane,the authors suggest that the andesitic rocks in the B.On ultramafic complex formed in a back-arc basin background,which connected the Jinghong and Nan back-arc basin during the Permian;while the andesitic tuff in the B.Kiophoulan-B.Houayhak belt erupted in the Sukhothai continental arc setting.
基金supported by the project of China Geological Survey(DD20221805,ZD20220301).
文摘1.Objective Southeast Asia has a 3500 km tin metallogenic belt in the world,extending from southern Yunnan Province to Bangka,Indonesia.This region is also the world’s largest one regarding tin production,which accounts for 85%of historical tin production globally(Lehmann B,2021).Myanmar is one of the main tin producers within this region(33000 t in 2020)and has become the key supplier after China and Indonesia.Research on tin mineralization in Myanmar mostly focused on ore-related granites,for zircon geochronology,magma evolution,and tectonic settings(Mao W et al.,2020).
基金supported in part by the National Natural Science Foundation of China (No. 52077222)the Fundamental Research Funds for the Central Universities (No. 19CX02016A)。
文摘—With the increase of converter-based renewable energy generation connected into the power grid, the interaction between renewable energy and grid impedance has introduced lots of new issues, among which the sub-and super-synchronous oscillation phenomenon makes a big concern. The linear active disturbance rejection control(LADRC) is a potential way to improve the damping characteristics of the grid-connected system, but the key factors and influencing mechanism on system stability are unknown. This paper establishes the equivalent impedance and coupling admittance models of a typical three-phase grid-connected converter. Then, the influence of the key factors such as the bandwidth of the LADRC and grid impedance on the stability and frequency coupling effect is assessed in detail. Finally, the theoretical analysis results are verified by simulations and experiments.
基金supported financially by the National Social Science Foundation of China(No.19CJY049)the National Natural Science Foundation of China(Nos.72173052,71803058,71873050)the Fundamental Research Funds from the Central Universities of China(No.2662022JGYJY02)。
文摘This study examines the impact of outward foreign direct investment(OFDI)on Chinese manufacturing firms'financialization and servitization.Using a difference-in-differences approach with propensity score matching,we found that OFDI encouraged firms'financial and service activities.The effects of OFDI on financialization were stronger for firms specializing in short-term financial assets,operating in labor and technology-intensive sectors,investing overseas to pursue production,resources and markets there,and investing in non-OECD and Belt and Road Initiative(BRI)countries.Meanwhile,firms investing overseas were more likely to provide services at the sale or postsale stages.Outward foreign direct investment has also boosted the service activities of firms operating in the technology-intensive sector by investing overseas to seek resources and markets,as well as investing in non-OECD and BRI countries.Finally,OFDI partially influenced the extent of financialization and servitization of firms by affecting their profit-making ability.
基金We acknowledge the financial support from the National Natural Science Foundation of China(Nos.U1662104 and 21576288).
文摘Large-scale electrolysis of water to produce high-purity hydrogen is one of the effective ways to solve the energy crisis and environmental pollution problems.However,efficient,cheap and stable catalysts are one of the bottlenecks for industrial application in water splitting.Herein,a facile one-step hydrothermal process was applied to fabricate Mn-doped nickel ferrite nanosheets(Mn-NiFe_(2)O_(4))which shown a low overpotential of 200 mV at 50 mA·cm^(-2)and a small Tafel slope of 47 mV·dec^(-1),together with a prominent turnover frequency(TOF)value(0.14 s^(-1))and robust stability.The in-situ UV-vis spectroscopy unveiled the surface reconstruction to generate NiOOH as active sites during oxygen evolution reaction(OER).The excellent electrocatalytic activity of Mn-NiFe_(2)O_(4)is attributed to the vertically grown nanosheets for exposure more active sites,rich oxygen vacancies,and the hybridization between Ni 3d and O 2p orbitals caused by Mn doping.This work should provide a facile strategy by Mn-doping to simultaneously engineer oxygen vacancies and electronic structure for synergistically triggering oxygen evolution reaction.
基金supported by the National Natural Science Foundation of China(22275021)Beijing Municipal Natural Science Foundation(L234064)+2 种基金Beijing Nova Program(20230484414)Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai(AMGM2024F23)Fundamental Research Funds for the Central Universities.
文摘Materials exhibiting persistently ultralong room-temperature phosphorescence(RTP)are capturing significant attention due to their long lifetimes,pronounced Stokes shifts,and efficient exciton utilization[1–3].These attributes position RTP materials as ideal candidates for advanced applications in information security,data storage,light-emitting diodes,bioimaging[4–6].
文摘The strategies including noncovalent macrocycle-confined supramolecular assembly and construction of rigid hydrogen-bond network have been verified as effective routes to brighten aqueous-phase room temperature phosphorescence.Molecule-based room-temperature phosphorescence(RTP)has attracted widespread attention in the fields of chemical sensors,optical anti-counterfeiting,information encoding and so on,due to unique characteristics of long excited-state lifetimes,large Stokes shifts and high signal-tonoise ratios[1,2].Currently,to obtain RTP with considerable efficiency and long lifetime,two brilliant strategies have been developed:one is the introduction of heavy atoms,which facilitates the spin-orbital coupling and intersystem crossing(ISC)from singlet to triplet states。
