Structure and composition of Earth are fundamental importance in exploring the dynamic evolution of the crust and mantle.The Qinling Orogenic Belt(QOB)is located between the North China plate and the South China Plate...Structure and composition of Earth are fundamental importance in exploring the dynamic evolution of the crust and mantle.The Qinling Orogenic Belt(QOB)is located between the North China plate and the South China Plate,and is one of the main orogenic belts in China.To explore the composition and origin of anisotropy and the low wave velocity zone of the QOB,ten rock samples(gneiss and schist)were collected from the five sites of the QOB and the P-and S-wave velocities of these samples were measured under 0.6 to 2.0 GPa and 100 to 550℃.The wave velocities increase with increasing pressure and decreasing temperature.The V_(P)and V_(S)of the schist and gneiss match the velocity of the middle and lower crust of the QOB,indicating that schist and gneiss are important component of the QOB.All the schist and gneiss samples exhibit obvious seismic anisotropy with 1.64%-17.42%for V_(S)and 2.93%-14.78%for V_(P)under conditions of crust and upper mantle.The CPO/LPO and layering distribution of mica in rock samples are the main reasons for this anisotropy.The V_(S)structures below the five sampled sites from seismic ambient noise tomography were built to explore the effect of schist and gneiss on the composition and structure of the QOB.The results indicate that orientation-arranged gneiss and schist driven by the tectonic stresses might be a new origin of the character of V_(P)/V_(S),seismic anisotropy,and the low velocity zone in the QOB.展开更多
The recently discovered endosulfan-degrading bacterial strain Alcaligenesfaecalis JBW4 was isolated from activated sludge. This strain is able to use endosulfan as a carbon and energy source. The optimal conditions fo...The recently discovered endosulfan-degrading bacterial strain Alcaligenesfaecalis JBW4 was isolated from activated sludge. This strain is able to use endosulfan as a carbon and energy source. The optimal conditions for the growth of strain JBW4 and for biodegradation by this strain were identified, and the metabolic products of endosulfan degradation were studied in detail. The maximum level of endosulfan biodegradation by strain JBW4 was obtained using broth at an initial pH of 7.0, an incubation temperature of 40℃ and an endosulfan concentration of I00 mg/L. The concentration of endosulfan was determined by gas chromatography. Strain JBW4 was able to degrade 87.5% of α-endosulfan and 83.9% of β-endosulfan within 5 days. These degradation rates are much higher than the previously reported bacterial strains. Endosulfan diol and endosulfan lactone were the major metabolites detected by gas chromatography-mass spectrometry; endosulfan sulfate, which is a persistent and toxic metabolite, was not detected. These results suggested that A. faecalis JBW4 degrades endosulfan via a non-oxidative pathway. The biodegradation of endosulfan by A. faecalis is reported for the first time. Additionally, the present study indicates that strain JBW4 may have potential for the biodegradation of endosulfan residues.展开更多
Helium diffusion in mantle minerals is crucial for understanding mantle structure and the dynamic processes of Earth's degassing.In this paper,we report helium incorporation and the mechanism of its diffusion in p...Helium diffusion in mantle minerals is crucial for understanding mantle structure and the dynamic processes of Earth's degassing.In this paper,we report helium incorporation and the mechanism of its diffusion in perfect crystals of quartz and coesite.The diffusion pathways,activation energies(Ea),and frequency factors of helium under ambient and high pressure conditions were calculated using Density Functional Theory(DFT)and the climbing image nudged elastic band(CI-NEB)method.The calculated diffusive coefficients of He in the quartz in different orientations are:D[100]=1.24×10^(−6)exp.(−26.83 kJ/mol/RT)m^(2)/s D[010]=1.11×10^(−6)exp.(−31.60 kJ/mol/RT)m^(2)/s.and in the coesite:D[100]=3.00×10^(−7)exp.(−33.79 kJ/mol/RT)m^(2)/s D[001]=2.21×10^(−6)exp.(−18.33 kJ/mol/RT)m^(2)/s.The calculated results indicate that diffusivity of helium is anisotropic in both quartz and coesite and that the degree of anisotropy is much more pronounced in coesite.Helium diffusion behavior in coesite under high pressures was investigated.The activation energies increased with pressure:Ea[100]increased from 33.79 kJ/mol to 58.36 kJ/mol,and Ea[001]increased from 18.33 kJ/mol to 48.87 kJ/mol as pressure increased from0 GPa to 12 GPa.Our calculations showed that helium is not be quantitatively retained in silica at typical surface temperatures on Earth,which is consistent with the findings from previous studies.These results have implications for discussion of the Earth's mantle evolution and for recognition thermal histories of ultra-high pressure(UHP)metamorphic terranes.展开更多
Large earthquakes can cause both casualties and economic losses, but they also provide invaluable opportunities for earthquake scientific research. Geofluids, due to their wide distribution, sensitive response to unde...Large earthquakes can cause both casualties and economic losses, but they also provide invaluable opportunities for earthquake scientific research. Geofluids, due to their wide distribution, sensitive response to underground conditions, and ease of observation, are widely applied in field investigations after earthquakes. Analyzing the origin of fluids, energy transfer processes, temperature/pressure conditions, and the spatial-temporal evolution of geofluids can provide valuable information concerning the mechanism of earthquake precursor anomalies, shortterm prediction methods, identification of the seismogenic faults, determination of earthquake risk, and the environmental impact of post-earthquake fluids. This article details post-earthquake scientific expeditions and research on fluid geochemistry in China and abroad, aimed at providing ideas and guidance for future scientific expedition work and geochemistry-related earthquake studies.展开更多
Sediments are one of the main carbon sinks in subduction zones,with CaCO_(3)and SiO_(2)being the main components in sediments.Their chemical stability plays a significant role in the form of carbon in the Earth’s man...Sediments are one of the main carbon sinks in subduction zones,with CaCO_(3)and SiO_(2)being the main components in sediments.Their chemical stability plays a significant role in the form of carbon in the Earth’s mantle.Here we report the reactions of CaCO_(3)with SiO_(2)in hydrated sediments at 0.8-2.0 GPa,400-500℃and redox-buffered conditions relevant to shallow subduction zones.Our results show that the reaction CaCO_(3)+SiO_(2)=CaSiO_(3)+C+O_(2)(fluid)occurs under CoCoO and IW buffered conditions to generate wollastonite(CaSiO_(3))and carbonaceous material(CM).Moreover,wollastonite is formed by the dissolution-crystallization process,which may be significantly affected by oxygen fugacity,leading to distinct crystallization habits(Yui,1966,Schott et al.,2012).Anhydrous experiments indicate that the reaction proceeds only in the presence of H2O within the pressure and temperature(P-T)range of this study.The reaction occurs more rapidly with aragonite-structured than calcite-structured CaCO_(3).Further,the experiment buffered with natural olivine at 1.0 GPa and 400℃proves that the above reaction can occur during serpentinization processes in shallow subduction zones.More importantly,nanoscale CM may be generated under relatively reducing conditions,exhibiting Raman characteristics of kerogen.These results provide new insights into how deep carbon is distributed in the Earth’s interior.展开更多
Main observation and conclusion The reaction of 2-alkynylanisoles/sulfides with SOCl_(2) and DMSO was conducted to conveniently furnish the biologically interesting 3-(methylthio)-benzo[b]furans/thiophenes via intramo...Main observation and conclusion The reaction of 2-alkynylanisoles/sulfides with SOCl_(2) and DMSO was conducted to conveniently furnish the biologically interesting 3-(methylthio)-benzo[b]furans/thiophenes via intramolecular cyclization.DMSO acts as a solvent as well as a sulfur source and can also be replaced with DMSO-d_(6),enabling the incorporation of the SCD3 moiety of DMSO-d_(6) to the 3-position of the heterocyclic frameworks.展开更多
The reaction of pyridin-2(1H)·ones with PhlCl_(2) and NH_(4)SCN enables an efficient regioselective thiocyanation,leading to the synthesis of the biologically interesting C5 thiocyanated 2-pyridones in good to hi...The reaction of pyridin-2(1H)·ones with PhlCl_(2) and NH_(4)SCN enables an efficient regioselective thiocyanation,leading to the synthesis of the biologically interesting C5 thiocyanated 2-pyridones in good to high yields.The mechanistic pathway of this metal-free approach is postulated to involve the formation of the reactive thiocyanogen chloride from the reaction of PhlCl_(2) and NH4SCN followed with the regioselective electrophilic thiocyanation of the pyridin-2(1H)-one ring.展开更多
基金supported by the National Natural Science Foundation of China(42174115 and 42330311)the Special Fund of the Institute of Earthquake Forecasting,China Earthquake Administration(CEAIEF20230301)the State key laboratory of earthquake dynamics(LED2021B02).
文摘Structure and composition of Earth are fundamental importance in exploring the dynamic evolution of the crust and mantle.The Qinling Orogenic Belt(QOB)is located between the North China plate and the South China Plate,and is one of the main orogenic belts in China.To explore the composition and origin of anisotropy and the low wave velocity zone of the QOB,ten rock samples(gneiss and schist)were collected from the five sites of the QOB and the P-and S-wave velocities of these samples were measured under 0.6 to 2.0 GPa and 100 to 550℃.The wave velocities increase with increasing pressure and decreasing temperature.The V_(P)and V_(S)of the schist and gneiss match the velocity of the middle and lower crust of the QOB,indicating that schist and gneiss are important component of the QOB.All the schist and gneiss samples exhibit obvious seismic anisotropy with 1.64%-17.42%for V_(S)and 2.93%-14.78%for V_(P)under conditions of crust and upper mantle.The CPO/LPO and layering distribution of mica in rock samples are the main reasons for this anisotropy.The V_(S)structures below the five sampled sites from seismic ambient noise tomography were built to explore the effect of schist and gneiss on the composition and structure of the QOB.The results indicate that orientation-arranged gneiss and schist driven by the tectonic stresses might be a new origin of the character of V_(P)/V_(S),seismic anisotropy,and the low velocity zone in the QOB.
基金supported by the National Natural Science Foundation of China(No.21377075,41071164,21277083,40801203,41001152)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20113702110007)
文摘The recently discovered endosulfan-degrading bacterial strain Alcaligenesfaecalis JBW4 was isolated from activated sludge. This strain is able to use endosulfan as a carbon and energy source. The optimal conditions for the growth of strain JBW4 and for biodegradation by this strain were identified, and the metabolic products of endosulfan degradation were studied in detail. The maximum level of endosulfan biodegradation by strain JBW4 was obtained using broth at an initial pH of 7.0, an incubation temperature of 40℃ and an endosulfan concentration of I00 mg/L. The concentration of endosulfan was determined by gas chromatography. Strain JBW4 was able to degrade 87.5% of α-endosulfan and 83.9% of β-endosulfan within 5 days. These degradation rates are much higher than the previously reported bacterial strains. Endosulfan diol and endosulfan lactone were the major metabolites detected by gas chromatography-mass spectrometry; endosulfan sulfate, which is a persistent and toxic metabolite, was not detected. These results suggested that A. faecalis JBW4 degrades endosulfan via a non-oxidative pathway. The biodegradation of endosulfan by A. faecalis is reported for the first time. Additionally, the present study indicates that strain JBW4 may have potential for the biodegradation of endosulfan residues.
基金the National Natural Science Foundation of China(Grant Nos.41174071,41573121)the open Foundation of the United Laboratory of High-Pressure Physics and Earthquake Science(Grant Nos.2019HPPES06 and 2019HPPES07)+1 种基金the Special Found of the Institute of Earthquake Forecasting,China Earthquake Administration(2018IEF010204)Key Laboratory of Earthquake Prediction,Institute pf Earthquake Forecasting,China Earthquake Administration(2017KLEP03).
文摘Helium diffusion in mantle minerals is crucial for understanding mantle structure and the dynamic processes of Earth's degassing.In this paper,we report helium incorporation and the mechanism of its diffusion in perfect crystals of quartz and coesite.The diffusion pathways,activation energies(Ea),and frequency factors of helium under ambient and high pressure conditions were calculated using Density Functional Theory(DFT)and the climbing image nudged elastic band(CI-NEB)method.The calculated diffusive coefficients of He in the quartz in different orientations are:D[100]=1.24×10^(−6)exp.(−26.83 kJ/mol/RT)m^(2)/s D[010]=1.11×10^(−6)exp.(−31.60 kJ/mol/RT)m^(2)/s.and in the coesite:D[100]=3.00×10^(−7)exp.(−33.79 kJ/mol/RT)m^(2)/s D[001]=2.21×10^(−6)exp.(−18.33 kJ/mol/RT)m^(2)/s.The calculated results indicate that diffusivity of helium is anisotropic in both quartz and coesite and that the degree of anisotropy is much more pronounced in coesite.Helium diffusion behavior in coesite under high pressures was investigated.The activation energies increased with pressure:Ea[100]increased from 33.79 kJ/mol to 58.36 kJ/mol,and Ea[001]increased from 18.33 kJ/mol to 48.87 kJ/mol as pressure increased from0 GPa to 12 GPa.Our calculations showed that helium is not be quantitatively retained in silica at typical surface temperatures on Earth,which is consistent with the findings from previous studies.These results have implications for discussion of the Earth's mantle evolution and for recognition thermal histories of ultra-high pressure(UHP)metamorphic terranes.
基金supported by the National Nature Science Foundation of China [Grant number 42073063, 41402298]Central Public-interest Scientific Institution Basal Research Fund (CEAIEF2022060101)+2 种基金Special Fund of the Institute of Earthquake Forecasting (2021IEF0101)United Laboratory of High-Pressure Physics and Earthquake Science(Grant number 2022HPPES01)a contribution to IGCP Project 724。
文摘Large earthquakes can cause both casualties and economic losses, but they also provide invaluable opportunities for earthquake scientific research. Geofluids, due to their wide distribution, sensitive response to underground conditions, and ease of observation, are widely applied in field investigations after earthquakes. Analyzing the origin of fluids, energy transfer processes, temperature/pressure conditions, and the spatial-temporal evolution of geofluids can provide valuable information concerning the mechanism of earthquake precursor anomalies, shortterm prediction methods, identification of the seismogenic faults, determination of earthquake risk, and the environmental impact of post-earthquake fluids. This article details post-earthquake scientific expeditions and research on fluid geochemistry in China and abroad, aimed at providing ideas and guidance for future scientific expedition work and geochemistry-related earthquake studies.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFF0804100)the United Laboratory of High-Pressure Physics and Earthquake Science(Grant No.2022HPPES01)Some experiments are supported by the Synergic Extreme Condition User Facility(SECUF).
文摘Sediments are one of the main carbon sinks in subduction zones,with CaCO_(3)and SiO_(2)being the main components in sediments.Their chemical stability plays a significant role in the form of carbon in the Earth’s mantle.Here we report the reactions of CaCO_(3)with SiO_(2)in hydrated sediments at 0.8-2.0 GPa,400-500℃and redox-buffered conditions relevant to shallow subduction zones.Our results show that the reaction CaCO_(3)+SiO_(2)=CaSiO_(3)+C+O_(2)(fluid)occurs under CoCoO and IW buffered conditions to generate wollastonite(CaSiO_(3))and carbonaceous material(CM).Moreover,wollastonite is formed by the dissolution-crystallization process,which may be significantly affected by oxygen fugacity,leading to distinct crystallization habits(Yui,1966,Schott et al.,2012).Anhydrous experiments indicate that the reaction proceeds only in the presence of H2O within the pressure and temperature(P-T)range of this study.The reaction occurs more rapidly with aragonite-structured than calcite-structured CaCO_(3).Further,the experiment buffered with natural olivine at 1.0 GPa and 400℃proves that the above reaction can occur during serpentinization processes in shallow subduction zones.More importantly,nanoscale CM may be generated under relatively reducing conditions,exhibiting Raman characteristics of kerogen.These results provide new insights into how deep carbon is distributed in the Earth’s interior.
基金We acknowledge the National Natural Science Foundation of China(No.21472136)for financial support.
文摘Main observation and conclusion The reaction of 2-alkynylanisoles/sulfides with SOCl_(2) and DMSO was conducted to conveniently furnish the biologically interesting 3-(methylthio)-benzo[b]furans/thiophenes via intramolecular cyclization.DMSO acts as a solvent as well as a sulfur source and can also be replaced with DMSO-d_(6),enabling the incorporation of the SCD3 moiety of DMSO-d_(6) to the 3-position of the heterocyclic frameworks.
基金Y.Du acknowledges the National Natural Science Foundation of China(No.22071175)for financial support.
文摘The reaction of pyridin-2(1H)·ones with PhlCl_(2) and NH_(4)SCN enables an efficient regioselective thiocyanation,leading to the synthesis of the biologically interesting C5 thiocyanated 2-pyridones in good to high yields.The mechanistic pathway of this metal-free approach is postulated to involve the formation of the reactive thiocyanogen chloride from the reaction of PhlCl_(2) and NH4SCN followed with the regioselective electrophilic thiocyanation of the pyridin-2(1H)-one ring.
