The northeast Tibetan plateau contains important inlbrmation on the northeastward growth of the Tibetan plateau. It is bounded by the Ordos Block to the east, the Alxa Block to the north, and the Tibetan Plateau to th...The northeast Tibetan plateau contains important inlbrmation on the northeastward growth of the Tibetan plateau. It is bounded by the Ordos Block to the east, the Alxa Block to the north, and the Tibetan Plateau to the south （inset in Fig. 1; Tapponnier et al., 2001）, and has undergone complex intracontinental deformation during the Cenozoic. In this region, the northeast-convex arcuate structures developed northeastward, and are composed of a series of Cenozoic NW-SE-trending basin-and-range terrain, i.e., the Haiyuan-Xingrenbu basin, Tongxin basin and Hongsipu basin, the Yueliang Shan-Nanhua Shan- Huangjiawa Shan, Xiang Shan-Xiangjing Shan, Yantong Shan and Luo Shan-Niushou Shah, which is geometrically similar with the American basin-range tectonics.展开更多
Rock–soil aggregate landslides(RSALs) are a common geological hazard in deeply incised valleys in southwestern China. Large-scale RSALs are widely distributed in the upper reaches of the Dadu River, Danba County, Sic...Rock–soil aggregate landslides(RSALs) are a common geological hazard in deeply incised valleys in southwestern China. Large-scale RSALs are widely distributed in the upper reaches of the Dadu River, Danba County, Sichuan Province, and are influenced by slope structure, which can be divided into open, lock, strip, and dumbbell types, as well as soil type and meso-structure, which can be classified as layered rock–soil aggregate, block-soil, and grainsoil. In this study, the evolution of four types of structures, such as layered-dumbbell, block-soil lock, banded block-soil, and block-soil open types, were analyzed by field surveys, surface and deep displacement monitoring, and Flac3 D. It was found that the Danba reach of the Dadu River showed incised valley through the evolution from wide to slow valley affected by internal and external geological processes since the Quaternary Glaciation. In the layered-dumbbell rock–soil aggregate, the main sliding pattern is multi-stage sliding at different depths. Circular sliding in the trailing edge and plane sliding along the bedrock in the front edge body occurin the block-soil-lock type aggregate. Large-scale multi-level and circular sliding over long distances occur in the banded block-soil aggregate. The blocksoil open type is stable, with only circular sliding occurring in local and shallow surfaces of the body. The monitoring and numerical simulation results further show that slope structure and regularity have diversified with RSALs. The results provide a basis for analyzing the stability mechanism of RSALs and preventing RSALs in deeply incised valleys.展开更多
High-efficiency photocatalytic hydrogen evolution(PHE)relies on the development of inexpensive,stable,and efficient photocatalysts.Cadmium sulfide(CdS),as a typical binary metal sulfide,has attracted considerable rese...High-efficiency photocatalytic hydrogen evolution(PHE)relies on the development of inexpensive,stable,and efficient photocatalysts.Cadmium sulfide(CdS),as a typical binary metal sulfide,has attracted considerable research attention due to its negative conduction band position,narrow band gap for visible-light response,and strong driving force for PHE.However,the construction of CdSbased photocatalysts and the PHE rate still require improvement for practical applications.In this review,recent advances in CdS-based photocatalysts for PHE via water splitting are systematically summarized.First,the semiconductor properties of CdS,including the crystal and band structures,are briefly introduced.Afterward,the fundamental mechanisms of PHE using semiconductor photocatalysts via water splitting are discussed.Subsequently,the photoactivity of bare CdS with different morphologies and structures,CdS with cocatalyst loading,and CdS-based heterojunction photocatalysts are reviewed and discussed in detail.Finally,the challenges and prospects for exploring advanced CdS-based photocatalysts are provided.展开更多
Developing non-precious metal-based bifunctional electrocatalysts capable for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is essential to achieve efficient water electrolysis for mass hydrog...Developing non-precious metal-based bifunctional electrocatalysts capable for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is essential to achieve efficient water electrolysis for mass hydrogen production,however it remains challenging.Here,we report the synthesis of hierarchical nanorod arrays comprising core-shell structured P-doped NiMoO4@NiFe-coordination polymer(denoted as P-NiMoO4@NiFeCP)as bifunctional electrocatalysts for water electrolysis.Furthermore,we systematically investigate the influence of NiFeCP shell thickness on electrocatalytic activity,manifesting the presence of strong interfacial synergetic effect between P-NiMoO4 and NiFeCP for boosting both the HER and OER.With advantageous hierarchical architectures and unique core-shell structures,optimized P-NiMoO_(4)@NiFeCP-7.3(7.3 is the shell thickness in nm)requires overpotentials of merely 256 and 297 mV to yield a current density of 1000 mA·cm^(−2)for the HER and OER in 1 M KOH,respectively.More importantly,it can serve as a bifunctional electrocatalyst for efficient and sustainable overall water electrolysis,delivering large current densities of 500 and 1000 mA·cm^(−2)at low cell voltages of 1.804 and 1.865 V,along with high stability of over 500 h at 1000 mA·cm−2,demonstrating the great potential of this electrocatalyst towards practical applications.展开更多
There are a number of structures and structural styles found in extensional tectonic settings of the world,and it is a big challenge to study the evolution of these structures. Evolution of structures formed in extens...There are a number of structures and structural styles found in extensional tectonic settings of the world,and it is a big challenge to study the evolution of these structures. Evolution of structures formed in extensional tectonic settings have been studied by researchers on different extensional basins of the world. Southern Sindh Monocline lies on the western corner of Indian Plate and the tectonic history of Indian plate has also experienced different extensional episodes, and its journey rifted from Gondwanaland to its final welding to Asia. The aim of this study is to figure out the evolution of structures in the subsurface of Southern Sindh Monocline, Pakistan using the seismic data interpretation and flattening of horizons approach. Structures within the subsurface of Southern Sindh Monocline have been characterized by different tectonic episodes of Indian plate while rifting from Gondwanaland, rifting from other plates at different geological times and to its collision with the Asia. Basic structures within study area are classified into nine types while the structural styles have been classified into six types as horst and grabens, dominos, crotch, synthetic and antithetic, negative and flashlight structural style. The structures within the study area revealed evidence for three major structural episodes which can be characterized as Episode 1: Structures associated with rifting of Indian plate from Gondwanaland during Late Jurassic to Early Cretaceous, Episode 2: Modification and reactivation of previous structures while Madagascar rifted from Indian Plate during the Middle Cretaceous and during Episode 3: Inversion and reactivation of structures occurred when Indian Plate collided with Asia during Early Eocene.展开更多
Alkaline electrochemical water oxidation powered by renewable energies is a promising and environmentally friendly way to produce hydrogen.The industrial water electrolyzers are commonly operated at a high current den...Alkaline electrochemical water oxidation powered by renewable energies is a promising and environmentally friendly way to produce hydrogen.The industrial water electrolyzers are commonly operated at a high current density,calling for abundant and durable active sites to participate in.The rational design of hierarchically structured electrocatalysts is thus essential to industrial water electrolyzers.Herein,we develop a Fe3+induced nanosizing strategy for fabricating such a hierarchical FeCo LDH@Co3O4(LDH:layered double hydroxide)nanostructure array for high-rate water oxidation.Density functional theory(DFT)simulations indicate that the introduction of Fe3+with a small ion radius and high electrical repulsion in the LDH layer distorted the LDH layer,resulting in a reduced nanosheet size and enabling the formation of a hierarchical structure.Such structure cannot be achieved without the participation of Fe3+cations.Benefiting from the significantly enhanced electrochemical surface areas and charge/mass transport due to the hierarchical structure together with the boosted intrinsic activity by electronic modulation of Fe3+,such FeCo LDH@Co3O4 electrode can deliver an industrial-level current density of 1,000 mA·cm-2 at a small overpotential of 392 mV for water oxidation.When assembled in a water electrolyzer,it delivers a current density of 100 mA·cm-2 at a low operation voltage of 1.61 V.Powered by solar light,the electrolyzer demonstrates high solar-to-hydrogen efficiency of 18.15%with stable and reproducible photoresponse.These results provide new insights for constructing hierarchical nanostructures for advanced water oxidation and other diverse applications.展开更多
The tectonic evolution of Southeast China during Late Mesozoic is a prominent topic. Numerous tectonic models on Late Mesozoic evolution ofSoutheast Chinahave been?published in the past 50 years. We synthesized many u...The tectonic evolution of Southeast China during Late Mesozoic is a prominent topic. Numerous tectonic models on Late Mesozoic evolution ofSoutheast Chinahave been?published in the past 50 years. We synthesized many up-to-date and precise zircon U-Pb ages, sedimentary strata, and regional structures and discussed the oxygen fugacity of magmas and related ore deposits. We also analyzed the most current tectonic models published by some scholars. A multistage tectonic stress evolution history during Late Mesozoic was constructed, which included the following stages: 1) Early-Middle Jurassic (196 - 175 Ma) extension, in which many bimodal volcanics formed;2) Middle-Late Jurassic (165 - 140 Ma) compression, which generated largescale gneissic granites, garnet-bearing granites, stratigraphic hiatus, and nappe structures;3) Early Cretaceous (140 ± 5 - 120 Ma) extension, which formed weakly deformed or undeformed granites, alkali granites, metamorphic core complexes, graben basins, and basic dike swarms;4) Early Cretaceous (120 - 110 Ma) compression, which generated nappe structures, volcanic hiatuses, and garnet-bearing granites;and 5) Early-Late Cretaceous (110 - 80 Ma) extension, which generated largescale bimodal volcanics, basic dike swarms, alkali granites, and graben basins. The Late Mesozoic tectonic evolution ofSoutheast Chinamay be attributed to the drifting history of the Paleo-Pacific plate. The drifting direction of the Paleo-Pacific plate has changed several times since 140 Ma, which led to major changes in the tectonicphenomena from Jurassic to Cretaceous and to the formation of Late Mesozoic mineral deposits.展开更多
The purpose of this review article is to present some of the recent contributions that show the use of thermo-dynamics to describe biological systems and their evolution, illustrating the agreement that this theory pr...The purpose of this review article is to present some of the recent contributions that show the use of thermo-dynamics to describe biological systems and their evolution, illustrating the agreement that this theory pre-sents with the field of evolution. Organic systems are described as thermodynamic systems where entropy is produced by the irreversible processes, considering as an established fact that this entropy is eliminated through their frontiers to preserve life. The necessary and sufficient conditions to describe the evolution of life in the negentropy principle are established. Underlining the fact that the necessary condition requires formulation, which is founded on the principle of minimum entropy production for open systems operating near equilibrium. Other formulations are mentioned, particularly the information theory, the energy inten-siveness hypothesis and the theory of open systems far from equilibrium. Finally suggesting the possibility of considering the lineal formulation as a viable alternative;that is, given the internal constrictions under which a biological system operates, it is possible that the validity of its application is broader than it has been suggested.展开更多
Numerical analysis was made for shoreline evolution in the vicinity ofcoastal structures, including spur dike, detached breakwaters. The nonlinear partial differentialequation was derived, and numerical solutions were...Numerical analysis was made for shoreline evolution in the vicinity ofcoastal structures, including spur dike, detached breakwaters. The nonlinear partial differentialequation was derived, and numerical solutions were obtained by the finite difference method. Thenumerical results show good agreement with previous analytical results.展开更多
The microstructure, chemical composition and morphology evolution of icosahedral quasicrystalline phase of Mg67.4Zn28.9Y3.7 ternary alloy were investigated in detail at different pouring temperatures by X-ray diffract...The microstructure, chemical composition and morphology evolution of icosahedral quasicrystalline phase of Mg67.4Zn28.9Y3.7 ternary alloy were investigated in detail at different pouring temperatures by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and energy-dispersive spectrum （EDS）. Low interracial energy favors the formation of l-phase. The experimental results show that the primary l-phase reveals petal-shaped with five and six branches, where each branch has facetted growth morphology with the size ranging from 50 to 100μm. As the temperature decreases, the polygon-shaped l-phase forms, attributed to the decomposition of branch of petal-shaped l-phase, and then it grows bigger and some of the fine polygons join together to form large polygons. Besides these, （α-Mg＋l-phase） eutectic structures disappear and the relative amount of Mg7Zn3 phase increases as the pouring temperature decreases. The chemical composition and morphology evolution of l-phase were also discussed.展开更多
ZnO nanosheets and nanoflakes were grown on alumina particles in the absence of surfactants via heterogeneous precipitation using urea, zinc acetate and bayerite as precursors. Thermo-gravimetric analysis （TGA）, X-r...ZnO nanosheets and nanoflakes were grown on alumina particles in the absence of surfactants via heterogeneous precipitation using urea, zinc acetate and bayerite as precursors. Thermo-gravimetric analysis （TGA）, X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FTIR） were used and the results indicated the formation of only two phases： wurtzite-type ZnO and γ-Al2O3. ZnO nanoflakes were grown on alumina particles in the samples with ZnO content of 40 and 60 wt%, By increasing the ZnO content to 80 wt%, a porous hierarchical structure of ZnO with nanosheet arrays appeared. Both of these nanoflakes and nanosheets were about 40-80 nm in thickness and about 1-2 μm in diameter. It was proposed that Zns（CO3）2（OH）6 nuclei undergo higher growth rates in thin sheets at edges of bayerite particles with a higher surface energy. The Brunauer-Emmett-Teller （BET） measurements proved a reachable high surface area for hierarchical structures of ZnO nanosheets, which could mainly be attributed to their unique growth on alumina particles. Also, UV absorption results revealed that ZnO--Al2O3 compositions still show the UV characteristic absorption of ZnO, which can evidence the presence of photocatalytic properties in ZnO-Al2O3 compositions.展开更多
Recently we developed a technique of ozone/vacuum annealing to continuously change the doping level of the surface of Bi_2Sr_2CaCu_2O_(8+)and measured a nearly whole superconducting dome on one surface by in-situ angl...Recently we developed a technique of ozone/vacuum annealing to continuously change the doping level of the surface of Bi_2Sr_2CaCu_2O_(8+)and measured a nearly whole superconducting dome on one surface by in-situ angle-resolved photoemission spectroscopy [arXiv: 1805.06450]. Here we study the evolution of the electronic structures of Bi_2Sr_2CaCu_2O_(8+)xusing this technique together with tight binding fits. The tight binding parameters are extracted to study their evolution with doping.展开更多
Recent studies indicate that there is a large buried body developing in the Sangzhi-Shimen tectonic belt,which is between the Xuefeng intracontinental deformation system and the Xiangexi tectonic belt.In order to expl...Recent studies indicate that there is a large buried body developing in the Sangzhi-Shimen tectonic belt,which is between the Xuefeng intracontinental deformation system and the Xiangexi tectonic belt.In order to explore the tectonic evolution and main deformation-controlling factors of the buried body,we carried out a series of studies and built two new models based on the latest seismic data and fault-related fold theory.These new models show that the deformation of the buried body in the north segment of the study area is different from that in the middle-south segment.After further study,we found the main factors leading to these differences were:(1)the magnitude of the principal stress,(2)the range of tectonic movements,and(3)the morphology and depth of the basement detachment.Subsequently,with the physical simulation experiments,a 3D evolution model of the study area was built.展开更多
基金supported by research grants from China Geological Survey (CGS) (No.1212011120100,1212011120099 and 1212011220259)
文摘The northeast Tibetan plateau contains important inlbrmation on the northeastward growth of the Tibetan plateau. It is bounded by the Ordos Block to the east, the Alxa Block to the north, and the Tibetan Plateau to the south （inset in Fig. 1; Tapponnier et al., 2001）, and has undergone complex intracontinental deformation during the Cenozoic. In this region, the northeast-convex arcuate structures developed northeastward, and are composed of a series of Cenozoic NW-SE-trending basin-and-range terrain, i.e., the Haiyuan-Xingrenbu basin, Tongxin basin and Hongsipu basin, the Yueliang Shan-Nanhua Shan- Huangjiawa Shan, Xiang Shan-Xiangjing Shan, Yantong Shan and Luo Shan-Niushou Shah, which is geometrically similar with the American basin-range tectonics.
基金funded by the National Science Foundation of China(Grant Nos.41702374,4177020938,2018YFC1505406)China Geological Survey projects(Grant Nos.DD20190640,20190505)
文摘Rock–soil aggregate landslides(RSALs) are a common geological hazard in deeply incised valleys in southwestern China. Large-scale RSALs are widely distributed in the upper reaches of the Dadu River, Danba County, Sichuan Province, and are influenced by slope structure, which can be divided into open, lock, strip, and dumbbell types, as well as soil type and meso-structure, which can be classified as layered rock–soil aggregate, block-soil, and grainsoil. In this study, the evolution of four types of structures, such as layered-dumbbell, block-soil lock, banded block-soil, and block-soil open types, were analyzed by field surveys, surface and deep displacement monitoring, and Flac3 D. It was found that the Danba reach of the Dadu River showed incised valley through the evolution from wide to slow valley affected by internal and external geological processes since the Quaternary Glaciation. In the layered-dumbbell rock–soil aggregate, the main sliding pattern is multi-stage sliding at different depths. Circular sliding in the trailing edge and plane sliding along the bedrock in the front edge body occurin the block-soil-lock type aggregate. Large-scale multi-level and circular sliding over long distances occur in the banded block-soil aggregate. The blocksoil open type is stable, with only circular sliding occurring in local and shallow surfaces of the body. The monitoring and numerical simulation results further show that slope structure and regularity have diversified with RSALs. The results provide a basis for analyzing the stability mechanism of RSALs and preventing RSALs in deeply incised valleys.
基金the Natural Science Foundation of Hainan Province(grant no.521RC495)the National Natural Science Foundation of China(grant nos.22109034,22109035,52164028,and 62105083)+1 种基金the Foundation of State Key Laboratory of Marine Resource Utilization in South China Sea(Hainan University,grant no.MRUKF2021029)the Start-up Research Foundation of Hainan University(grant nos.KYQD(ZR)-20008,20082,20083,20084,21065,21124,and 21125).
文摘High-efficiency photocatalytic hydrogen evolution(PHE)relies on the development of inexpensive,stable,and efficient photocatalysts.Cadmium sulfide(CdS),as a typical binary metal sulfide,has attracted considerable research attention due to its negative conduction band position,narrow band gap for visible-light response,and strong driving force for PHE.However,the construction of CdSbased photocatalysts and the PHE rate still require improvement for practical applications.In this review,recent advances in CdS-based photocatalysts for PHE via water splitting are systematically summarized.First,the semiconductor properties of CdS,including the crystal and band structures,are briefly introduced.Afterward,the fundamental mechanisms of PHE using semiconductor photocatalysts via water splitting are discussed.Subsequently,the photoactivity of bare CdS with different morphologies and structures,CdS with cocatalyst loading,and CdS-based heterojunction photocatalysts are reviewed and discussed in detail.Finally,the challenges and prospects for exploring advanced CdS-based photocatalysts are provided.
基金the Shenzhen Science and Technology Program(Nos.SGDX20201103095802006,RCYX20200714114535052,JCYJ20190808150001775,and JCYJ20190808143007479)the National Natural Science Foundation of China(Nos.U21A20312 and 21975162).
文摘Developing non-precious metal-based bifunctional electrocatalysts capable for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)is essential to achieve efficient water electrolysis for mass hydrogen production,however it remains challenging.Here,we report the synthesis of hierarchical nanorod arrays comprising core-shell structured P-doped NiMoO4@NiFe-coordination polymer(denoted as P-NiMoO4@NiFeCP)as bifunctional electrocatalysts for water electrolysis.Furthermore,we systematically investigate the influence of NiFeCP shell thickness on electrocatalytic activity,manifesting the presence of strong interfacial synergetic effect between P-NiMoO4 and NiFeCP for boosting both the HER and OER.With advantageous hierarchical architectures and unique core-shell structures,optimized P-NiMoO_(4)@NiFeCP-7.3(7.3 is the shell thickness in nm)requires overpotentials of merely 256 and 297 mV to yield a current density of 1000 mA·cm^(−2)for the HER and OER in 1 M KOH,respectively.More importantly,it can serve as a bifunctional electrocatalyst for efficient and sustainable overall water electrolysis,delivering large current densities of 500 and 1000 mA·cm^(−2)at low cell voltages of 1.804 and 1.865 V,along with high stability of over 500 h at 1000 mA·cm−2,demonstrating the great potential of this electrocatalyst towards practical applications.
文摘There are a number of structures and structural styles found in extensional tectonic settings of the world,and it is a big challenge to study the evolution of these structures. Evolution of structures formed in extensional tectonic settings have been studied by researchers on different extensional basins of the world. Southern Sindh Monocline lies on the western corner of Indian Plate and the tectonic history of Indian plate has also experienced different extensional episodes, and its journey rifted from Gondwanaland to its final welding to Asia. The aim of this study is to figure out the evolution of structures in the subsurface of Southern Sindh Monocline, Pakistan using the seismic data interpretation and flattening of horizons approach. Structures within the subsurface of Southern Sindh Monocline have been characterized by different tectonic episodes of Indian plate while rifting from Gondwanaland, rifting from other plates at different geological times and to its collision with the Asia. Basic structures within study area are classified into nine types while the structural styles have been classified into six types as horst and grabens, dominos, crotch, synthetic and antithetic, negative and flashlight structural style. The structures within the study area revealed evidence for three major structural episodes which can be characterized as Episode 1: Structures associated with rifting of Indian plate from Gondwanaland during Late Jurassic to Early Cretaceous, Episode 2: Modification and reactivation of previous structures while Madagascar rifted from Indian Plate during the Middle Cretaceous and during Episode 3: Inversion and reactivation of structures occurred when Indian Plate collided with Asia during Early Eocene.
基金the financial support from the National Natural Science Foundation of China(Nos.22025208,22075300,and 21902162)the China National Postdoctoral Program for Innovative Talents(No.BX2021319)+1 种基金the DNL Cooperation Fund,CAS(No.DNL202008)the Chinese Academy of Sciences.
文摘Alkaline electrochemical water oxidation powered by renewable energies is a promising and environmentally friendly way to produce hydrogen.The industrial water electrolyzers are commonly operated at a high current density,calling for abundant and durable active sites to participate in.The rational design of hierarchically structured electrocatalysts is thus essential to industrial water electrolyzers.Herein,we develop a Fe3+induced nanosizing strategy for fabricating such a hierarchical FeCo LDH@Co3O4(LDH:layered double hydroxide)nanostructure array for high-rate water oxidation.Density functional theory(DFT)simulations indicate that the introduction of Fe3+with a small ion radius and high electrical repulsion in the LDH layer distorted the LDH layer,resulting in a reduced nanosheet size and enabling the formation of a hierarchical structure.Such structure cannot be achieved without the participation of Fe3+cations.Benefiting from the significantly enhanced electrochemical surface areas and charge/mass transport due to the hierarchical structure together with the boosted intrinsic activity by electronic modulation of Fe3+,such FeCo LDH@Co3O4 electrode can deliver an industrial-level current density of 1,000 mA·cm-2 at a small overpotential of 392 mV for water oxidation.When assembled in a water electrolyzer,it delivers a current density of 100 mA·cm-2 at a low operation voltage of 1.61 V.Powered by solar light,the electrolyzer demonstrates high solar-to-hydrogen efficiency of 18.15%with stable and reproducible photoresponse.These results provide new insights for constructing hierarchical nanostructures for advanced water oxidation and other diverse applications.
文摘The tectonic evolution of Southeast China during Late Mesozoic is a prominent topic. Numerous tectonic models on Late Mesozoic evolution ofSoutheast Chinahave been?published in the past 50 years. We synthesized many up-to-date and precise zircon U-Pb ages, sedimentary strata, and regional structures and discussed the oxygen fugacity of magmas and related ore deposits. We also analyzed the most current tectonic models published by some scholars. A multistage tectonic stress evolution history during Late Mesozoic was constructed, which included the following stages: 1) Early-Middle Jurassic (196 - 175 Ma) extension, in which many bimodal volcanics formed;2) Middle-Late Jurassic (165 - 140 Ma) compression, which generated largescale gneissic granites, garnet-bearing granites, stratigraphic hiatus, and nappe structures;3) Early Cretaceous (140 ± 5 - 120 Ma) extension, which formed weakly deformed or undeformed granites, alkali granites, metamorphic core complexes, graben basins, and basic dike swarms;4) Early Cretaceous (120 - 110 Ma) compression, which generated nappe structures, volcanic hiatuses, and garnet-bearing granites;and 5) Early-Late Cretaceous (110 - 80 Ma) extension, which generated largescale bimodal volcanics, basic dike swarms, alkali granites, and graben basins. The Late Mesozoic tectonic evolution ofSoutheast Chinamay be attributed to the drifting history of the Paleo-Pacific plate. The drifting direction of the Paleo-Pacific plate has changed several times since 140 Ma, which led to major changes in the tectonicphenomena from Jurassic to Cretaceous and to the formation of Late Mesozoic mineral deposits.
文摘The purpose of this review article is to present some of the recent contributions that show the use of thermo-dynamics to describe biological systems and their evolution, illustrating the agreement that this theory pre-sents with the field of evolution. Organic systems are described as thermodynamic systems where entropy is produced by the irreversible processes, considering as an established fact that this entropy is eliminated through their frontiers to preserve life. The necessary and sufficient conditions to describe the evolution of life in the negentropy principle are established. Underlining the fact that the necessary condition requires formulation, which is founded on the principle of minimum entropy production for open systems operating near equilibrium. Other formulations are mentioned, particularly the information theory, the energy inten-siveness hypothesis and the theory of open systems far from equilibrium. Finally suggesting the possibility of considering the lineal formulation as a viable alternative;that is, given the internal constrictions under which a biological system operates, it is possible that the validity of its application is broader than it has been suggested.
文摘Numerical analysis was made for shoreline evolution in the vicinity ofcoastal structures, including spur dike, detached breakwaters. The nonlinear partial differentialequation was derived, and numerical solutions were obtained by the finite difference method. Thenumerical results show good agreement with previous analytical results.
基金supported by the National Natural Science Foundation of China (Grant No.50571081)the Aeronautical Science Foundation of China (Grant No.04G53042)
文摘The microstructure, chemical composition and morphology evolution of icosahedral quasicrystalline phase of Mg67.4Zn28.9Y3.7 ternary alloy were investigated in detail at different pouring temperatures by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and energy-dispersive spectrum （EDS）. Low interracial energy favors the formation of l-phase. The experimental results show that the primary l-phase reveals petal-shaped with five and six branches, where each branch has facetted growth morphology with the size ranging from 50 to 100μm. As the temperature decreases, the polygon-shaped l-phase forms, attributed to the decomposition of branch of petal-shaped l-phase, and then it grows bigger and some of the fine polygons join together to form large polygons. Besides these, （α-Mg＋l-phase） eutectic structures disappear and the relative amount of Mg7Zn3 phase increases as the pouring temperature decreases. The chemical composition and morphology evolution of l-phase were also discussed.
文摘ZnO nanosheets and nanoflakes were grown on alumina particles in the absence of surfactants via heterogeneous precipitation using urea, zinc acetate and bayerite as precursors. Thermo-gravimetric analysis （TGA）, X-ray diffraction （XRD） and Fourier transform infrared spectroscopy （FTIR） were used and the results indicated the formation of only two phases： wurtzite-type ZnO and γ-Al2O3. ZnO nanoflakes were grown on alumina particles in the samples with ZnO content of 40 and 60 wt%, By increasing the ZnO content to 80 wt%, a porous hierarchical structure of ZnO with nanosheet arrays appeared. Both of these nanoflakes and nanosheets were about 40-80 nm in thickness and about 1-2 μm in diameter. It was proposed that Zns（CO3）2（OH）6 nuclei undergo higher growth rates in thin sheets at edges of bayerite particles with a higher surface energy. The Brunauer-Emmett-Teller （BET） measurements proved a reachable high surface area for hierarchical structures of ZnO nanosheets, which could mainly be attributed to their unique growth on alumina particles. Also, UV absorption results revealed that ZnO--Al2O3 compositions still show the UV characteristic absorption of ZnO, which can evidence the presence of photocatalytic properties in ZnO-Al2O3 compositions.
基金supported by the Ministry of Science and Technology of China(Grant Nos.2016YFA0401000,2016YFA0300600,2015CB921300,and 2015CB921000)the National Natural Science Foundation of China(Grant Nos.11227903,and 11574371)and the Chinese Academy of Sciences(Grant Nos.XDB07000000,and XDPB08-1)
文摘Recently we developed a technique of ozone/vacuum annealing to continuously change the doping level of the surface of Bi_2Sr_2CaCu_2O_(8+)and measured a nearly whole superconducting dome on one surface by in-situ angle-resolved photoemission spectroscopy [arXiv: 1805.06450]. Here we study the evolution of the electronic structures of Bi_2Sr_2CaCu_2O_(8+)xusing this technique together with tight binding fits. The tight binding parameters are extracted to study their evolution with doping.
基金supported by the National Science and Technology Major Projects(No.2011ZX05008-001)the National Natural Science Foundation of China(Nos.40739906,41272237)
文摘Recent studies indicate that there is a large buried body developing in the Sangzhi-Shimen tectonic belt,which is between the Xuefeng intracontinental deformation system and the Xiangexi tectonic belt.In order to explore the tectonic evolution and main deformation-controlling factors of the buried body,we carried out a series of studies and built two new models based on the latest seismic data and fault-related fold theory.These new models show that the deformation of the buried body in the north segment of the study area is different from that in the middle-south segment.After further study,we found the main factors leading to these differences were:(1)the magnitude of the principal stress,(2)the range of tectonic movements,and(3)the morphology and depth of the basement detachment.Subsequently,with the physical simulation experiments,a 3D evolution model of the study area was built.
