The 12 May 2008 Wenchuan earthquake （Ms=8.0） struck on the Longmen Shan foreland thrust zone. The event took place within the context of long-term uplift of the Longmen Shan range as a result of the extensive eastwa...The 12 May 2008 Wenchuan earthquake （Ms=8.0） struck on the Longmen Shan foreland thrust zone. The event took place within the context of long-term uplift of the Longmen Shan range as a result of the extensive eastward-extrusion of crustal materials from the Tibetan plateau against the rheologically strong crust of the Sichuan Basin. The Longmen Shan range is charac- terized by a Pre-Sinian crystalline complex constrained by the Maoxian-Wenchuan-Kangding ductile detach- ment at the western margin and the Yingxiu-Beichuan- Luding ductile thrust at the eastern margin. The Long- men Shan uplift was initiated by intracontinental sub- duction between the Songpan-Ganzi terrane and the Yangtze block during the Pre-Cenozoic. The uplift rate was increased considerably by the collision between the Indian and Eurasian plates since -50 Ma. The Wenchuan earthquake resulted in two major NE-strik- ing coseismic ruptures （i.e., the -275 km long Yingxiu- Beichuan-Qingchuan fault and the -100 km long Anx- ian-Guanxian fault）. Field investigations combined with focal solutions and seismic reflection profiles suggest that the coseismic ruptures are steeply dipping close-to- pure reverse or right reverse oblique slip faults in the -15 km thick upper crust. These faults are unfavorably oriented for frictional slip in the horizontally compres- sional regime, so that they need a long recurrence interval to accumulate the tectonic stress and fluid pres- sure to critically high levels for the formation of strong earthquakes at a given locality. It is also found that all the large earthquakes （Ms〉7.0） occurred in the fault zones across which the horizontal movement velocities measured by the GPS are markedly low （〈3 mm/yr）. The faults, which constitute the northeastern fronts of the enlarging Tibetan plateau against the strong Sichuan Basin, Ala Shan and Ordos blocks, are very destructive, although their average recurrence intervals are generally long.展开更多
In this study,the hot rolled medium manganese steel containing titanium was solution treated at 1,000°C and followed by aging treatment at 500,550,and 600°C.The influence of aging treatment on mechanical pro...In this study,the hot rolled medium manganese steel containing titanium was solution treated at 1,000°C and followed by aging treatment at 500,550,and 600°C.The influence of aging treatment on mechanical properties and wear resistance of medium manganese steel reinforced with Ti(C,N)particles was investigated.It was found that the matrix of medium manganese steel was austenite.The austenite grain size was refined,and Ti(C,N)particles were precipitated after aging treatment.Compared to that of the as-hot rolled sample,the initial hardness of 500°C aged sample increased by 9.5%to 312.86 HV,whose impact energy was more than doubled to 148.5 J.As the aging temperature raised to 600°C,the initial hardness changed slightly.However,the impact energy dropped significantly to 8 J due to the aggregation of Mn at the grain boundaries.In addition,the main wear mechanisms of the samples were fatigue wear and abrasive wear.It was worth noting that 500°C aged sample exhibited the best wear resistance under a 300 N applied load,whose wear loss was just half of the as-hot rolled sample.The relationship between wear loss and mechanical properties indicated that the wear resistance of medium manganese steel was independent of the initial hardness.The large difference in the wear resistance was predominately due to the outstanding work hardening ability of 500°C aged sample,whose strengthening mechanisms were contributed from transformation induced plasticity(TRIP)effect,dislocation strengthening,twinning induced plasticity(TWIP)effect,and precipitation strengthening.展开更多
The Tarim Basin is the largest, oil-bearing, superimposed basin in the northwest of China. The evolution and tectonic properties of the initial Tarim Basin have been hotly disputed and remain enigmatic. The Neoprotero...The Tarim Basin is the largest, oil-bearing, superimposed basin in the northwest of China. The evolution and tectonic properties of the initial Tarim Basin have been hotly disputed and remain enigmatic. The Neoproterozoic basin is covered by a vast desert and a huge-thickness of sedimentary strata, has experienced multiple tectonic movements, had a low signal to noise ratios(SNRs) of deep seismic reflection data, all of which have posed critical obstacles to research. We analysed four field outcrops, 18 wells distributed throughout the basin, 27 reprocessed seismic reflection profiles with higher SNRs across the basin and many ancillary local 2D and 3D profiles and aeromagnetic data. We found about 20 normal fault-controlled rifting depressions of the Cryogenian and Ediacaran scattered throughout the basin, which developed on the Precambrian metamorphic and crystalline basement. The structural framework is clearly different from that of the overlying Phanerozoic. The rifting depressions consist of mainly half grabens, symmetrical troughs and horst-grabens. From the northeast to southwest of the basin,they are divided into three rifting depression groups with the WNW, ENE, and NW-trends that are mainly controlled by normal faults. The maximum thicknesses of the strata are up to 4100 m. From the Cryogenian to Ediacaran, most of the main inherited faults to active and eventually ceased at the end of the Ediacaran or Early Cambrian, while subsidence centres appeared and migrated eastward along the faults. They revealed that the different parts of the Tarim continental block were in NNE-SSWoriented and NNW-SSE-oriented extensional paleo-stress fields(relative to the present) during the Neoproterozoic, and were accompanied by clockwise shearing. According to the analysis of the activities of syn-sedimentary faults, filling sediments,magmatic events, and coordination with aeromagnetic anomalies, the tectonic properties of the fault depressions are different and are primarily continental rifts or intra-continental fault-controlled basins. The rifting phases mainly occurred from 0.8–0.61 Ga.The formation of the rifting depression was associated with the initial opening of the South Altun-West Kunlun Ocean and the South Tianshan Ocean, which were located at the northern and southern margins of the Tarim Block, respectively, in response to the break-up of the Supercontinent Rodinia and the initial opening of the Proto-Tethys Ocean.展开更多
To reveal the petrological characteristics, metamorphic evolution histon and tectonic setting of the pelitic granulites from Ailaoshan Orogen, Uest Yunnan, China, a comprehensive study in mineral chemistry, petrogeoch...To reveal the petrological characteristics, metamorphic evolution histon and tectonic setting of the pelitic granulites from Ailaoshan Orogen, Uest Yunnan, China, a comprehensive study in mineral chemistry, petrogeochemistry and geochronology studies is presented in this paper. Two metamorphic stages of the granulites can be established:(1) the peak metamorphism recorded by the mineral assemblage of garnet, kyanite, K-feidspar and rutile, and the initial retrograde metamorphism shown by the mineral assemblage of garnet, sillimanite, sapphirine, spinel, K-feldspar, plagioclase and biotite;(2) the superim-posed metamorphism recorded by the mineral assemblage of biotite, muscovite, plagioclase, quartz and ilmenite. Zircon LA-ICP-MS U-Pb dating indicates that the protolith of the granulite was deposited after 337 Ma. The initial retrograde metamorphism occurred at P-T conditions of 8.6-12 kbar at 850-920℃ estimated by mineral assemblages, the low pressure limit of kyanite stability and GBPQ geothermobarometer in Indosinian (about 235 Ma), and the late superimposed metamorphism occurred at the P-T condition of 3.5-3.9 kbar at 572-576℃ estimated by GBPQ geothermobarometer since 33Ma. The first stage was related to the amalgamation of the South China and Indochina blocks during the Triassic, and the second stage was possibly related with the large scale sinistral slip-shearing since the Oligocene. It is inferred that the upper continental crust was suhducted/underthrusted to the lower continental crust (deeper than 30 km) and underwent granulite-facies metamorphism and then quickly exhumed to the middle-upper crust (10-12 km) and initial retrograde metamorphism occurred due to the collision of the Indochina and South China blocks during Indosinian, which was followed by superimposition of the second stage of metamorphism since the Oligocene.展开更多
This work proposes a modified activated carbon support,with defects and heteroatoms(N,P-ACs)by nitrogen and phosphorus doping to load non-noble nickel to catalyze aromatic compound hydrogenation.The Ni/N,P-ACs-900(pre...This work proposes a modified activated carbon support,with defects and heteroatoms(N,P-ACs)by nitrogen and phosphorus doping to load non-noble nickel to catalyze aromatic compound hydrogenation.The Ni/N,P-ACs-900(prepared at 900℃)showed promising catalytic activity in liquid-phase 1,5-dinitronaphthalene hydrogenation with a 1,5-diaminonaphthalene yield of 95.8% under the mild condition of 100℃,which is comparable to the commercial Pd/C catalyst.The nitrogen species were burned off at 900℃,causing more defects for nickel metal loading,facilitating the interaction between the supports and the nickel metal,and resulting in highly dispersed metal particles.The computational study of the nickel binding energy has been conducted using density functional theory.It exhibits that the defects formed by heteroatom doping are beneficial to nickel anchoring and deposition to form highly uniform nickel particles.The phosphorus species in combination with the defects are suitable for H_(2) adsorption and dissociation.These results reveal that the heteroatomic doping on the active carbon shows significant effects in the hydrogenation of the liquid-phase aromatic compounds.These findings could provide a promising route for the rational design of aromatic compound hydrogenation catalysts to significantly decrease the cost by instead using noble metal catalysts in the industry.展开更多
文摘The 12 May 2008 Wenchuan earthquake （Ms=8.0） struck on the Longmen Shan foreland thrust zone. The event took place within the context of long-term uplift of the Longmen Shan range as a result of the extensive eastward-extrusion of crustal materials from the Tibetan plateau against the rheologically strong crust of the Sichuan Basin. The Longmen Shan range is charac- terized by a Pre-Sinian crystalline complex constrained by the Maoxian-Wenchuan-Kangding ductile detach- ment at the western margin and the Yingxiu-Beichuan- Luding ductile thrust at the eastern margin. The Long- men Shan uplift was initiated by intracontinental sub- duction between the Songpan-Ganzi terrane and the Yangtze block during the Pre-Cenozoic. The uplift rate was increased considerably by the collision between the Indian and Eurasian plates since -50 Ma. The Wenchuan earthquake resulted in two major NE-strik- ing coseismic ruptures （i.e., the -275 km long Yingxiu- Beichuan-Qingchuan fault and the -100 km long Anx- ian-Guanxian fault）. Field investigations combined with focal solutions and seismic reflection profiles suggest that the coseismic ruptures are steeply dipping close-to- pure reverse or right reverse oblique slip faults in the -15 km thick upper crust. These faults are unfavorably oriented for frictional slip in the horizontally compres- sional regime, so that they need a long recurrence interval to accumulate the tectonic stress and fluid pres- sure to critically high levels for the formation of strong earthquakes at a given locality. It is also found that all the large earthquakes （Ms〉7.0） occurred in the fault zones across which the horizontal movement velocities measured by the GPS are markedly low （〈3 mm/yr）. The faults, which constitute the northeastern fronts of the enlarging Tibetan plateau against the strong Sichuan Basin, Ala Shan and Ordos blocks, are very destructive, although their average recurrence intervals are generally long.
基金The authors acknowledge the support from the National Natural Foundation of China(Grant No.51974084)Taiyuan University of Science and Technology Scientific Research Initial Funding(Grant Nos.20202039 and 20212052)China Postdoctoral Science Foundation(Grant Nos.2020M673194 and 2020T130329).
文摘In this study,the hot rolled medium manganese steel containing titanium was solution treated at 1,000°C and followed by aging treatment at 500,550,and 600°C.The influence of aging treatment on mechanical properties and wear resistance of medium manganese steel reinforced with Ti(C,N)particles was investigated.It was found that the matrix of medium manganese steel was austenite.The austenite grain size was refined,and Ti(C,N)particles were precipitated after aging treatment.Compared to that of the as-hot rolled sample,the initial hardness of 500°C aged sample increased by 9.5%to 312.86 HV,whose impact energy was more than doubled to 148.5 J.As the aging temperature raised to 600°C,the initial hardness changed slightly.However,the impact energy dropped significantly to 8 J due to the aggregation of Mn at the grain boundaries.In addition,the main wear mechanisms of the samples were fatigue wear and abrasive wear.It was worth noting that 500°C aged sample exhibited the best wear resistance under a 300 N applied load,whose wear loss was just half of the as-hot rolled sample.The relationship between wear loss and mechanical properties indicated that the wear resistance of medium manganese steel was independent of the initial hardness.The large difference in the wear resistance was predominately due to the outstanding work hardening ability of 500°C aged sample,whose strengthening mechanisms were contributed from transformation induced plasticity(TRIP)effect,dislocation strengthening,twinning induced plasticity(TWIP)effect,and precipitation strengthening.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41872121 & 41630207)the Basic Scientific Research Projects of the Chinese Academy of Geological Sciences (Grant Nos. JYYWF20180903 & JYYWF20182103)+1 种基金the Science Research project from the Northwest Subsidiary of SINOPEC (Grant No. KY2013-S-024)the work project of Chinese Geological Survey (Grant Nos. 12120115002101, DD20160022, DD20160169 & 12120115026901)
文摘The Tarim Basin is the largest, oil-bearing, superimposed basin in the northwest of China. The evolution and tectonic properties of the initial Tarim Basin have been hotly disputed and remain enigmatic. The Neoproterozoic basin is covered by a vast desert and a huge-thickness of sedimentary strata, has experienced multiple tectonic movements, had a low signal to noise ratios(SNRs) of deep seismic reflection data, all of which have posed critical obstacles to research. We analysed four field outcrops, 18 wells distributed throughout the basin, 27 reprocessed seismic reflection profiles with higher SNRs across the basin and many ancillary local 2D and 3D profiles and aeromagnetic data. We found about 20 normal fault-controlled rifting depressions of the Cryogenian and Ediacaran scattered throughout the basin, which developed on the Precambrian metamorphic and crystalline basement. The structural framework is clearly different from that of the overlying Phanerozoic. The rifting depressions consist of mainly half grabens, symmetrical troughs and horst-grabens. From the northeast to southwest of the basin,they are divided into three rifting depression groups with the WNW, ENE, and NW-trends that are mainly controlled by normal faults. The maximum thicknesses of the strata are up to 4100 m. From the Cryogenian to Ediacaran, most of the main inherited faults to active and eventually ceased at the end of the Ediacaran or Early Cambrian, while subsidence centres appeared and migrated eastward along the faults. They revealed that the different parts of the Tarim continental block were in NNE-SSWoriented and NNW-SSE-oriented extensional paleo-stress fields(relative to the present) during the Neoproterozoic, and were accompanied by clockwise shearing. According to the analysis of the activities of syn-sedimentary faults, filling sediments,magmatic events, and coordination with aeromagnetic anomalies, the tectonic properties of the fault depressions are different and are primarily continental rifts or intra-continental fault-controlled basins. The rifting phases mainly occurred from 0.8–0.61 Ga.The formation of the rifting depression was associated with the initial opening of the South Altun-West Kunlun Ocean and the South Tianshan Ocean, which were located at the northern and southern margins of the Tarim Block, respectively, in response to the break-up of the Supercontinent Rodinia and the initial opening of the Proto-Tethys Ocean.
基金supported by the National Natural Science Foundation of China (Nos. 91755101, 41272219)the Chinese Ministry of Science and Technology (No. Sinoprobe-05-03)the China Geological Survey (No. DD20160022-07)
文摘To reveal the petrological characteristics, metamorphic evolution histon and tectonic setting of the pelitic granulites from Ailaoshan Orogen, Uest Yunnan, China, a comprehensive study in mineral chemistry, petrogeochemistry and geochronology studies is presented in this paper. Two metamorphic stages of the granulites can be established:(1) the peak metamorphism recorded by the mineral assemblage of garnet, kyanite, K-feidspar and rutile, and the initial retrograde metamorphism shown by the mineral assemblage of garnet, sillimanite, sapphirine, spinel, K-feldspar, plagioclase and biotite;(2) the superim-posed metamorphism recorded by the mineral assemblage of biotite, muscovite, plagioclase, quartz and ilmenite. Zircon LA-ICP-MS U-Pb dating indicates that the protolith of the granulite was deposited after 337 Ma. The initial retrograde metamorphism occurred at P-T conditions of 8.6-12 kbar at 850-920℃ estimated by mineral assemblages, the low pressure limit of kyanite stability and GBPQ geothermobarometer in Indosinian (about 235 Ma), and the late superimposed metamorphism occurred at the P-T condition of 3.5-3.9 kbar at 572-576℃ estimated by GBPQ geothermobarometer since 33Ma. The first stage was related to the amalgamation of the South China and Indochina blocks during the Triassic, and the second stage was possibly related with the large scale sinistral slip-shearing since the Oligocene. It is inferred that the upper continental crust was suhducted/underthrusted to the lower continental crust (deeper than 30 km) and underwent granulite-facies metamorphism and then quickly exhumed to the middle-upper crust (10-12 km) and initial retrograde metamorphism occurred due to the collision of the Indochina and South China blocks during Indosinian, which was followed by superimposition of the second stage of metamorphism since the Oligocene.
基金This work was supported by the National Natural Science Foundation of China(Grant No.21908185)Project of Hunan Provincial Natural Science Foundation of China(Grant No.2018JJ3497)+1 种基金Project of Hunan Provincial Education Department(Grant Nos.19B572 and 20B547)Collaborative Innovation Center of New Chemical Technologies for Environmental Benignity and Efficient Resource Utilization,and National Department of Education Engineering Research Centre for Chemical Process Simulation and Optimization.
文摘This work proposes a modified activated carbon support,with defects and heteroatoms(N,P-ACs)by nitrogen and phosphorus doping to load non-noble nickel to catalyze aromatic compound hydrogenation.The Ni/N,P-ACs-900(prepared at 900℃)showed promising catalytic activity in liquid-phase 1,5-dinitronaphthalene hydrogenation with a 1,5-diaminonaphthalene yield of 95.8% under the mild condition of 100℃,which is comparable to the commercial Pd/C catalyst.The nitrogen species were burned off at 900℃,causing more defects for nickel metal loading,facilitating the interaction between the supports and the nickel metal,and resulting in highly dispersed metal particles.The computational study of the nickel binding energy has been conducted using density functional theory.It exhibits that the defects formed by heteroatom doping are beneficial to nickel anchoring and deposition to form highly uniform nickel particles.The phosphorus species in combination with the defects are suitable for H_(2) adsorption and dissociation.These results reveal that the heteroatomic doping on the active carbon shows significant effects in the hydrogenation of the liquid-phase aromatic compounds.These findings could provide a promising route for the rational design of aromatic compound hydrogenation catalysts to significantly decrease the cost by instead using noble metal catalysts in the industry.
