The Lucaogou Formation in the Jimusar Sag of the eastern Junggar Basin is an important sedimentary stratum accumulating huge amounts of lacustrine tight oil in China, where organic-rich rocks are commonly observed. Fo...The Lucaogou Formation in the Jimusar Sag of the eastern Junggar Basin is an important sedimentary stratum accumulating huge amounts of lacustrine tight oil in China, where organic-rich rocks are commonly observed. Focusing on the Lucaogou Formation, a precise analysis of the inorganic and organic petrology and the inorganic geochemistry characteristics was conducted. The paleoclimate and paleoenvironment during sedimentation of the Lucaogou Formation were established,and the key factors that were controlling the accumulation of organic matter during this time were identified. The results of this study suggest that during the sedimentation of the Lucaogou Formation, the paleoclimate periodically changed from a humid environment to an arid environment. As a result, the salinity of the water and the redox environment fluctuated.During the sedimentation period, the lake showed su cient nutrient supplies and a high primary productivity. The interval studies in the Lucaogou Formation were divided into five sedimentary cycles, where the first, second, and fifth sedimentary cycles consisted of cyclical paleoclimate fluctuations varied from a humid environment to an arid environment and shifted back to a humid environment with levels of salinity from low to high and decreased again. The third and fourth cycles have cyclical fluctuations from a humid to an arid environment and corresponding salinity variation between low and high levels.During the period when organic-rich rocks in the Lucaogou Formation deposited in the Jimusar Sag, the paleoclimate and the water body were suitable for lower aquatic organisms to flourish. As a result, its paleoproductivity was high, especially during the early period of each cycle. A quiet deep water body is likely to form an anoxic environment at the bottom and is also good for accumulation and preservation of organisms. Fine-grained sediments were accumulated at a low deposition rate, with a low dilution of organic matter. Therefore, high paleoproductivity provided a su cient volume of organisms in the studied area in a quiet deep water body with an anoxic environment and these were the key factors controlling formation of organic-rich rocks.展开更多
The genesis of the fine crystalline dolomites that exhibit good to excellent reservoir properties in the upper fourth member of the Eocene Shahejie Formation(Es4s)around the Sikou Sag, Bohai Bay Basin, is uncertain....The genesis of the fine crystalline dolomites that exhibit good to excellent reservoir properties in the upper fourth member of the Eocene Shahejie Formation(Es4s)around the Sikou Sag, Bohai Bay Basin, is uncertain. This paper investigates the formation mechanisms of this fine crystalline dolomite using XRD, SEM, thin section analysis and geochemical data. The stratigraphy of the Sikou lacustrine carbonate is dominated by the repetition of metre-scale, high-frequency deposition cycles, and the amount of dolomite within a cycle increases upward from the cycle bottom. These dolomite crystals are 2–30 μm in length, subhedral to anhedral in shape and typically replace both grains and matrix. They also occur as rim cement and have thin lamellae within ooid cortices. Textural relations indicate that the dolomite predates equant sparry calcite cement and coarse calcite cement. The Sr concentrations of dolomites range from 900 to 1200 ppm. Dolomite δ18O values(-11.3 to-8.2 ‰ PDB) are depleted relative to calcite mudstone(-8.3 to-5.4 ‰ PDB) that precipitated from lake water, while δ13C values(0.06–1.74 ‰ PDB) are within the normal range of calcite mudstone values(-2.13 to 1.99 ‰ PDB). High87Sr/86Sr values(0.710210–0.710844) indicate that amounts of Ca2+ and Mg2+have been derived from the chemical weathering of Palaeozoic carbonate bedrocks. The high strontium concentration indicates that hypersaline conditions were maintainedduring the formation of the dolomites and that the dolomites were formed by the replacement of precursor calcite or by direct precipitation.展开更多
AIM: To investigate the impact of titanium dioxide nanoparticles(Ti O2NPs) on embryonic development and retinal neurogenesis.METHODS: The agglomeration and sedimentation of Ti O2 NPs solutions at different dilutions w...AIM: To investigate the impact of titanium dioxide nanoparticles(Ti O2NPs) on embryonic development and retinal neurogenesis.METHODS: The agglomeration and sedimentation of Ti O2 NPs solutions at different dilutions were observed,and the ultraviolet-visible spectra of their supernatants were measured. Zebrafish embryos were experimentally exposed to Ti O2 NPs until 72 h postfertilization(hpf). The retinal neurogenesis and distribution of the microglia were analyzed by immunohistochemistry and whole mount in situ hybridization.RESULTS: The 1 mg/L was determined to be an appropriate exposure dose. Embryos exposed to Ti O2 NPs had a normal phenotype. The neurogenesis was initiated on time, and ganglion cells, cones and rods were well differentiated at 72 hpf. The expression of fms m RNA and the 4C4 antibody, which were specific to microglia in the central nervous system(CNS), closely resembled their endogenous profile.CONCLUSION: These data demonstrate that short-term exposure to Ti O2 NPs at a low dose does not lead to delayed embryonic development or retinal neurotoxicity.展开更多
The 2017 Geoscience Frontiers Annual Convention was held in Beijing, China during October 19e21, 2017 hosted by China University of Geosciences, Beijing (Fig. 1). This convention assembled earth scientists from seven ...The 2017 Geoscience Frontiers Annual Convention was held in Beijing, China during October 19e21, 2017 hosted by China University of Geosciences, Beijing (Fig. 1). This convention assembled earth scientists from seven countries, including Australia (Dr. Christopher Spencer and Dr. Stijn Glorie), Korea (Dr. S. Kwon), India (Dr. Shaji Erath), Japan (Dr. Toshiaki Tsunogae and Dr. Masaki Yoshida), Russia (Dr. Inna Safonova), UK (Dr. Nick Roberts), China, and also representatives from Elsevier (Beijing).展开更多
Magnetic skyrmions,the topological spin textures firstly observed in chiral magnets,have aroused huge interest due to their emergent electromagnetism and potential applications in spintronics.Over the last decade,sign...Magnetic skyrmions,the topological spin textures firstly observed in chiral magnets,have aroused huge interest due to their emergent electromagnetism and potential applications in spintronics.Over the last decade,significant efforts have been devoted to skyrmion generation,stabilization,and dynamics.In most cases,the theoretical and experimental investigations have been performed in the materials where the skyrmions have a circular shape.As we know,magnetic anisotropy(K_(u))and Dzyaloshinskii-Moriya interaction(DMI)play key roles in the stabilization of the skyrmions in chiral magnets.Therefore,modifying the Kand DMI provide new degrees of freedom for studying the related physics and applications of skyrmions in addition to engineering their energetics and sizes.In this review,the latest progress on the study of the anisotropic deformation of magnetic skyrmions(i.e.,elliptical magnetic skyrmions)is summarized.The physical origins and important advantages of elliptical magnetic skyrmions are mainly focused on.This review gives an insight into the understanding of the physical mechanisms of elliptical magnetic skyrmion-hosting systems.展开更多
The pressure nitric acid leaching of alkali-pre- treated low-grade limonitic laterite, as well as removing impurity AI(III) and preparing intermediate product of nickel/cobalt sulphide from leaching liquor were inve...The pressure nitric acid leaching of alkali-pre- treated low-grade limonitic laterite, as well as removing impurity AI(III) and preparing intermediate product of nickel/cobalt sulphide from leaching liquor were investi- gated. After pretreatment, iron exists in the form of amorphous iron oxides, while nickel is adsorbed on the surface of iron oxides in the form of nickel oxide. The preferable pressure leaching conditions are determined as follows: leaching temperature of 458 K, leaching duration of 60 min, initial acidity of nitric acid of 1.90 mol.L-~ and liquid to solid ratio of 3:1 (volume to mass ratio). Under these conditions, the leaching efficiencies of Ni, Co and A1 are 95 %, 88 % and 55 %, respectively, and that of Fe is less than 1%. The loss rates of Ni and Co are 1.8 % and 1.5 %, respectively, during the step of removing impurity AI(III). The sulphide precipitation process produces the interim production of nickel/cobalt sulphides, recovering greater than 99 % of Ni and Co in the purified solution. The iron-rich (〉60 %) pressure leaching residue with low Cr, S can be further reclaimed as the raw materials for iron making.展开更多
Investigating the formation and evolution of coarse-grained deposits in modern lakes and the relevant controlling conditions is indispensable to the prediction of reservoir sandbodies, disaster prediction,and limnolog...Investigating the formation and evolution of coarse-grained deposits in modern lakes and the relevant controlling conditions is indispensable to the prediction of reservoir sandbodies, disaster prediction,and limnological research. The source-to-sink system of coarse-grained deposits in Lake Chenghai, a deep,scarped Late Quaternary lake, was investigated in this study based on 62 outcrops, Advanced Land Observing Satellite(ALOS) digital elevation model(DEM) data, and regional geological survey data. The findings include the following:(1) the source areas of coarse-grained deposits in Lake Chenghai were lithologically classified into carbonate source areas, basaltic source areas and siliciclastic source areas, and were geomorphically categorized as scarp type or confluence type. Subaqueous colluvial aprons have formed downstream of the carbonate source areas and scarp-type basaltic source areas, while Gilbert-type deltas have formed downstream of siliciclastic source areas and confluence-type basaltic source areas.(2) The formation and evolution of coarse-grained deposits are controlled by the sediment flux that evolves in synchrony with the geomorphic evolution of the source areas and the sink regimes. Scarps represent the initial landform of the source areas.Source material rolls off or slides down scarps or forms small-scale debris flows before entering the lake. The source material initially formed subaqueous colluvial apron(synonymous with subaqueous fans) where sufficient space was present to accommodate sediments and the basement angle exceeded than the natural angle of repose. As weathering and denudation have progressed, the initial scarps have transformed into confluencetype slopes, and the source material has formed medium-and large-scale debris flows that have entered the lake, resulting in an increase in sediment flux. Consequently, the subaqueous colluvial aprons have rapidly grown and developed subaerial deposits, which have evolved into larger-scale Gilbert-type deltas that overlie the initial aprons.(3) The morphology and distribution of coarse-grained deposits vary in response to differences in quantity and composition of materials from different source areas, which resulting from different rates of weathering and denudation and different sediment input regimes. Firstly, the size and surface slope angle of a subaqueous colluvial apron from a carbonate source are smaller than those of a subaqueous colluvial apron of basaltic origin. Secondly, a Gilbert-type delta from a basaltic source features a greater slope angle and a thicker topset than does a Gilbert-type delta of siliciclastic origin, and the latter exhibits a longer foreset and a thicker bottomset than in the former. Thirdly, the sizes of subaqueous colluvial aprons are not strongly correlated with the sizes of the source areas, while the sizes of Gilbert-type deltas are.展开更多
基金supported by the National Science and Technology Major Program of China(Grant No.2017ZX05009002)the National Basic Research Program of China(Grant No.2014CB239002)+1 种基金the Natural Science Foundation of Shandong Province,China(Grant No.ZR2014DQ016)the Natural Science Foundation Joint Special of Shandong Province,China(Grant No.ZR2016DL05)
文摘The Lucaogou Formation in the Jimusar Sag of the eastern Junggar Basin is an important sedimentary stratum accumulating huge amounts of lacustrine tight oil in China, where organic-rich rocks are commonly observed. Focusing on the Lucaogou Formation, a precise analysis of the inorganic and organic petrology and the inorganic geochemistry characteristics was conducted. The paleoclimate and paleoenvironment during sedimentation of the Lucaogou Formation were established,and the key factors that were controlling the accumulation of organic matter during this time were identified. The results of this study suggest that during the sedimentation of the Lucaogou Formation, the paleoclimate periodically changed from a humid environment to an arid environment. As a result, the salinity of the water and the redox environment fluctuated.During the sedimentation period, the lake showed su cient nutrient supplies and a high primary productivity. The interval studies in the Lucaogou Formation were divided into five sedimentary cycles, where the first, second, and fifth sedimentary cycles consisted of cyclical paleoclimate fluctuations varied from a humid environment to an arid environment and shifted back to a humid environment with levels of salinity from low to high and decreased again. The third and fourth cycles have cyclical fluctuations from a humid to an arid environment and corresponding salinity variation between low and high levels.During the period when organic-rich rocks in the Lucaogou Formation deposited in the Jimusar Sag, the paleoclimate and the water body were suitable for lower aquatic organisms to flourish. As a result, its paleoproductivity was high, especially during the early period of each cycle. A quiet deep water body is likely to form an anoxic environment at the bottom and is also good for accumulation and preservation of organisms. Fine-grained sediments were accumulated at a low deposition rate, with a low dilution of organic matter. Therefore, high paleoproductivity provided a su cient volume of organisms in the studied area in a quiet deep water body with an anoxic environment and these were the key factors controlling formation of organic-rich rocks.
基金supported by the National Basic Research Program of China (Grant No. 2014CB239002)Natural Science Foundation of Shandong Province, China (Grant No. ZR2014DQ016)
文摘The genesis of the fine crystalline dolomites that exhibit good to excellent reservoir properties in the upper fourth member of the Eocene Shahejie Formation(Es4s)around the Sikou Sag, Bohai Bay Basin, is uncertain. This paper investigates the formation mechanisms of this fine crystalline dolomite using XRD, SEM, thin section analysis and geochemical data. The stratigraphy of the Sikou lacustrine carbonate is dominated by the repetition of metre-scale, high-frequency deposition cycles, and the amount of dolomite within a cycle increases upward from the cycle bottom. These dolomite crystals are 2–30 μm in length, subhedral to anhedral in shape and typically replace both grains and matrix. They also occur as rim cement and have thin lamellae within ooid cortices. Textural relations indicate that the dolomite predates equant sparry calcite cement and coarse calcite cement. The Sr concentrations of dolomites range from 900 to 1200 ppm. Dolomite δ18O values(-11.3 to-8.2 ‰ PDB) are depleted relative to calcite mudstone(-8.3 to-5.4 ‰ PDB) that precipitated from lake water, while δ13C values(0.06–1.74 ‰ PDB) are within the normal range of calcite mudstone values(-2.13 to 1.99 ‰ PDB). High87Sr/86Sr values(0.710210–0.710844) indicate that amounts of Ca2+ and Mg2+have been derived from the chemical weathering of Palaeozoic carbonate bedrocks. The high strontium concentration indicates that hypersaline conditions were maintainedduring the formation of the dolomites and that the dolomites were formed by the replacement of precursor calcite or by direct precipitation.
基金Supported by the National Natural Science Foundation of China (No.81301080)the National Key Technology R&D Program of China (2012BAI08B06)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry
文摘AIM: To investigate the impact of titanium dioxide nanoparticles(Ti O2NPs) on embryonic development and retinal neurogenesis.METHODS: The agglomeration and sedimentation of Ti O2 NPs solutions at different dilutions were observed,and the ultraviolet-visible spectra of their supernatants were measured. Zebrafish embryos were experimentally exposed to Ti O2 NPs until 72 h postfertilization(hpf). The retinal neurogenesis and distribution of the microglia were analyzed by immunohistochemistry and whole mount in situ hybridization.RESULTS: The 1 mg/L was determined to be an appropriate exposure dose. Embryos exposed to Ti O2 NPs had a normal phenotype. The neurogenesis was initiated on time, and ganglion cells, cones and rods were well differentiated at 72 hpf. The expression of fms m RNA and the 4C4 antibody, which were specific to microglia in the central nervous system(CNS), closely resembled their endogenous profile.CONCLUSION: These data demonstrate that short-term exposure to Ti O2 NPs at a low dose does not lead to delayed embryonic development or retinal neurotoxicity.
文摘The 2017 Geoscience Frontiers Annual Convention was held in Beijing, China during October 19e21, 2017 hosted by China University of Geosciences, Beijing (Fig. 1). This convention assembled earth scientists from seven countries, including Australia (Dr. Christopher Spencer and Dr. Stijn Glorie), Korea (Dr. S. Kwon), India (Dr. Shaji Erath), Japan (Dr. Toshiaki Tsunogae and Dr. Masaki Yoshida), Russia (Dr. Inna Safonova), UK (Dr. Nick Roberts), China, and also representatives from Elsevier (Beijing).
基金financially supported by Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110553)Science Center of the National Science Foundation of China(No.52088101)+5 种基金Beijing Natural Science Foundation(No.Z190009)the National Natural Science Foundation of China(NSFC,Nos.11874409 and 11904056)K.C.Wong Education Foundation(No.GJTD-2019-14)China Postdoctoral Science Foundation(No.2020M670499)Guangzhou basic and applied basic research project(No.202102020053)the startup funding from Songshan Lake Materials Laboratory(No.Y1D1071S511)。
文摘Magnetic skyrmions,the topological spin textures firstly observed in chiral magnets,have aroused huge interest due to their emergent electromagnetism and potential applications in spintronics.Over the last decade,significant efforts have been devoted to skyrmion generation,stabilization,and dynamics.In most cases,the theoretical and experimental investigations have been performed in the materials where the skyrmions have a circular shape.As we know,magnetic anisotropy(K_(u))and Dzyaloshinskii-Moriya interaction(DMI)play key roles in the stabilization of the skyrmions in chiral magnets.Therefore,modifying the Kand DMI provide new degrees of freedom for studying the related physics and applications of skyrmions in addition to engineering their energetics and sizes.In this review,the latest progress on the study of the anisotropic deformation of magnetic skyrmions(i.e.,elliptical magnetic skyrmions)is summarized.The physical origins and important advantages of elliptical magnetic skyrmions are mainly focused on.This review gives an insight into the understanding of the physical mechanisms of elliptical magnetic skyrmion-hosting systems.
基金Project supported by the National Natural Science Foundation of China(No.51405160)the Guangzhou Pearl River New Talent Project(No.201710010064)+2 种基金the High-level Personnel Special Support Plan from Guangdong Province(No.2016TQ03X289)the Instrument Research Project of the National Natural Science Foundation of China(No.81327001)the Application-oriented R&D Projects of Guangdong Province(No.2015B090920002),China
基金financially supported by the National Natural Science Foundation of China (Nos. 51274044, 51304023, and U1302274)
文摘The pressure nitric acid leaching of alkali-pre- treated low-grade limonitic laterite, as well as removing impurity AI(III) and preparing intermediate product of nickel/cobalt sulphide from leaching liquor were investi- gated. After pretreatment, iron exists in the form of amorphous iron oxides, while nickel is adsorbed on the surface of iron oxides in the form of nickel oxide. The preferable pressure leaching conditions are determined as follows: leaching temperature of 458 K, leaching duration of 60 min, initial acidity of nitric acid of 1.90 mol.L-~ and liquid to solid ratio of 3:1 (volume to mass ratio). Under these conditions, the leaching efficiencies of Ni, Co and A1 are 95 %, 88 % and 55 %, respectively, and that of Fe is less than 1%. The loss rates of Ni and Co are 1.8 % and 1.5 %, respectively, during the step of removing impurity AI(III). The sulphide precipitation process produces the interim production of nickel/cobalt sulphides, recovering greater than 99 % of Ni and Co in the purified solution. The iron-rich (〉60 %) pressure leaching residue with low Cr, S can be further reclaimed as the raw materials for iron making.
基金the National Natural Science Foundation of China (Grant No. 42172115,41972099, 42102153)the China Postdoctoral Science Foundation (Grant No. 2021M693500)the National Major Science and Technology Projects of China(Grant No. 2017ZX05009-002, 2017ZX05072-002)。
文摘Investigating the formation and evolution of coarse-grained deposits in modern lakes and the relevant controlling conditions is indispensable to the prediction of reservoir sandbodies, disaster prediction,and limnological research. The source-to-sink system of coarse-grained deposits in Lake Chenghai, a deep,scarped Late Quaternary lake, was investigated in this study based on 62 outcrops, Advanced Land Observing Satellite(ALOS) digital elevation model(DEM) data, and regional geological survey data. The findings include the following:(1) the source areas of coarse-grained deposits in Lake Chenghai were lithologically classified into carbonate source areas, basaltic source areas and siliciclastic source areas, and were geomorphically categorized as scarp type or confluence type. Subaqueous colluvial aprons have formed downstream of the carbonate source areas and scarp-type basaltic source areas, while Gilbert-type deltas have formed downstream of siliciclastic source areas and confluence-type basaltic source areas.(2) The formation and evolution of coarse-grained deposits are controlled by the sediment flux that evolves in synchrony with the geomorphic evolution of the source areas and the sink regimes. Scarps represent the initial landform of the source areas.Source material rolls off or slides down scarps or forms small-scale debris flows before entering the lake. The source material initially formed subaqueous colluvial apron(synonymous with subaqueous fans) where sufficient space was present to accommodate sediments and the basement angle exceeded than the natural angle of repose. As weathering and denudation have progressed, the initial scarps have transformed into confluencetype slopes, and the source material has formed medium-and large-scale debris flows that have entered the lake, resulting in an increase in sediment flux. Consequently, the subaqueous colluvial aprons have rapidly grown and developed subaerial deposits, which have evolved into larger-scale Gilbert-type deltas that overlie the initial aprons.(3) The morphology and distribution of coarse-grained deposits vary in response to differences in quantity and composition of materials from different source areas, which resulting from different rates of weathering and denudation and different sediment input regimes. Firstly, the size and surface slope angle of a subaqueous colluvial apron from a carbonate source are smaller than those of a subaqueous colluvial apron of basaltic origin. Secondly, a Gilbert-type delta from a basaltic source features a greater slope angle and a thicker topset than does a Gilbert-type delta of siliciclastic origin, and the latter exhibits a longer foreset and a thicker bottomset than in the former. Thirdly, the sizes of subaqueous colluvial aprons are not strongly correlated with the sizes of the source areas, while the sizes of Gilbert-type deltas are.