Controlled by the squeezing collision between the Yangtze block and the North China block and the left movement of the Tanlu fault, the Xu-Su region developed into an arc-shaped nappe structure, and many destructive e...Controlled by the squeezing collision between the Yangtze block and the North China block and the left movement of the Tanlu fault, the Xu-Su region developed into an arc-shaped nappe structure, and many destructive earthquakes occurred in its periphery. The geological structure of this area is complex, and there is the possibility of moderate and strong earthquakes. To further explore the crust density structure and identify the main faults and deep structural features in the Xu-Su region, based on the observed seismic data and gravity/GNSS co-site observation data, combined with the EGM2008 global gravity field model, we obtained the density of three-dimensional structure using cross gradient method joint inversion. Based on this, a geological model of the Xu-Su region was established. The results show that the crustal density anomaly amplitude within 0-25 km of the Xu-Su region ranges from-280 to 490 kg/m3, showing a zonal distribution in east-west direction and a segmented north-south direction. There are several density anomalies in the shallow(0-4 km) region at Tongshan, Huaibei, Xiayi, Woyang, etc. The density anomalies are significantly correlated with the distribution of regional faults. The density structure is divided into two large regions by Subei fault, which can be further divided along the eastwest Kouziji-Nanzhao fault and Guzhen-Huaiyuan fault. The earthquakes are obviously related to the regional fault activity and the spatial distribution of abnormal bodies. The earthquake-prone areas(5-15 km) correspond to the abnormal density mutation zone, upper uplift zone, and transformation zone near Xiaoxian, Tongshan, and Xushuanglou faults. The comprehensive results show three weak seismic activity areas in the whole region, which are located near the Huaibei, Xiaoxian, and Wohe faults. The results provide theoretical support for seismic risk analysis in this area, and these three areas should be emphasized in future seismic hazard analysis.展开更多
The structural features and three-dimensional nature of the charge density wave （CDW） state of the layered chalcogenide 1T-TaSe2-xTex （0≤x≤2.0） are characterized by Cs-corrected transmission electron microscopy ...The structural features and three-dimensional nature of the charge density wave （CDW） state of the layered chalcogenide 1T-TaSe2-xTex （0≤x≤2.0） are characterized by Cs-corrected transmission electron microscopy measurements. Notable changes of both average structure and the CDW state arising from Te substitution for Se are clearly demonstrated in samples with x〉0.3. The commensurate CDW state characterized by the known star-of-David clustering in the 1T-TaSe2 crystal becomes visibly unstable with Te substitution and vanishes when x=0.3. The 1T-TaSe2-xTex （0.3≤x≤1.3） samples generally adopt a remarkable incommensurate CDW state with monoclinic distortion, which could be fundamentally in correlation with the strong qq-dependent electron-phonon coupling-induced period-lattice-distortion as identified in TaTe22. Systematic analysis demonstrates that the occurrence of superconductivity is related to the suppression of the commensurate CDW phase and the presence of discommensuration is an evident structural feature observed in the superconducting samples.展开更多
The deformation mechanisms of the Tianshan orogenic belt(TOB)are one of the most important unresolved issues in the collision of the Indian and Eurasian plates.To better understand the lithospheric deformation of the ...The deformation mechanisms of the Tianshan orogenic belt(TOB)are one of the most important unresolved issues in the collision of the Indian and Eurasian plates.To better understand the lithospheric deformation of the eastern Tianshan orogenic belt,we combined the S-wave tomography and gravity data to develop a three-dimensional(3D)density model of the crust and upper mantle beneath the eastern Tianshan area.Results show that the crust of the eastern Tianshan is mainly characterized by positive density anomalies,revealing widespread subduction-related magmatism during the Paleozoic.We however have also observed extensive low-density anomalies beneath the eastern Tianshan at depths deeper than~100 km,which is likely linked to a relatively hot mantle.The most fundamental differences of the lithosphere within the eastern Tianshan occur in the uppermost mantle.The uppermost mantle layers in the Bogda Shan and Harlik Shan are relatively dense.This is likely associated with an eclogite body in the uppermost mantle.The most significant negative anomaly of the uppermost mantle is however found in the Jueluotage tectonic belt and the central Tianshan Block and is possibly associated with depleted mantle material.We suggest that these differences related to compositional changes may control the strength of the lithospheric mantle and have affected the uplift of the northern and southern segments of the eastern Tianshan after the Permian.展开更多
We derive explicit expressions for quantum discord and classical correlation for an X structure density matrix. Based on the characteristics of the expressions, the quantum discord and the classical correlation are ea...We derive explicit expressions for quantum discord and classical correlation for an X structure density matrix. Based on the characteristics of the expressions, the quantum discord and the classical correlation are easily obtained and compared under different initial conditions using a novel analytical method. We explain the relationships among quantum discord, classical correlation, and entanglement, and further find that the quantum discord is not always larger than the entanglement measured by concurrence in a general two-qubit X state. The new method, which is different from previous approaches, has certain guiding significance for analysing quantum discord and classical correlation of a two-qubit X state, such as a mixed state.展开更多
This paper presents the 3D density structure of crust in the Longmenshan range and adjacent areas, with constraints from seismic and density data. The density structure of crust shows that the immense boundary plane o...This paper presents the 3D density structure of crust in the Longmenshan range and adjacent areas, with constraints from seismic and density data. The density structure of crust shows that the immense boundary plane of density distribution in relation to the Longmeshan fault belt is extended downward to -80 km deep. This density boundary plane dips towards the northwest and crosses the Moho. With the proximity to the Longmenshan fault belt, it has a larger magnitude of undulation in the upper and middle crust levels. Density changes abruptly across Longmeshan fault belt. Seismic data show that most of the earthquakes in the Longmenshan area after the 2008 Ms8.0 Wenchuan Earthquake occurred within the upper to middle crust. These earthquakes are clearly distributed in the uplifted region of the basement. A few of them occurs in the transitional zone between the uplifted and subsided areas. But most of the earthquakes distributes in transitional zone from subsided to uplifted areas in the upper and middle crust where relatively large density changes occurr The 3D density structure of crust in the Longmenshan and adjacent areas can thus help us to understand the pattern of overthrusting from the standpoint of deep crust and where the earthquakes occurred.展开更多
To determine the lateral and vertical variations in crustal structure and their influence on the seismicity of the Western North China Craton,the Trans-North China Orogen,and the surrounding regions,the wavelet multi-...To determine the lateral and vertical variations in crustal structure and their influence on the seismicity of the Western North China Craton,the Trans-North China Orogen,and the surrounding regions,the wavelet multi-scale structures,Moho depth,crustal density structures,and isostatic state are modelled using Bouguer gravity anomaly data,topography,and earthquake focal mechanisms.We obtained homogeneous crustal densities and deviations of<1 km between the crustal thicknesses estimated from the isostatic model and those inverted from the Bouguer gravity anomalies in the Ordos Block,the Inner Mongolia Suture Zone,the Sichuan Basin,and the Jizhong Depression.These results provide new evidence for relatively simple and stable continental crustal structures,and indicate that these regions will remain stable in both the vertical and lateral directions.The Hetao Graben,Yinchuan Graben,Weihe Basin,and Shanxi graben system have heterogeneous crustal densities and are isostatically over-compensated.In contrast,the crust beneath the Yinshan Uplift,Lvliang Uplift,and northern and central Taihang Uplift is thin and under-compensated.The heterogeneous crustal densities and non-isostatic state beneath the Tibetan Plateau and Qinling Central China Orogen indicate that these two blocks are unstable in the vertical and lateral directions.Although Cenozoic deformation of the North China Craton is thought to be driven by lithospheric stresses related to the India-Eurasia collision and Pacific slab retreat in South East Asia,we suggest that gravitational potential energy created by the heterogeneous crustal structure modulates these first-order forces.The results of this study could constrain the causes of seismicity in systems surrounding the Ordos Block.展开更多
The electronic band structures, densities of states （DOSs）, and projected densities of states （PDOSs） of the wurtzite In1-xGaxN with x=0, 0.0625, 0.125 are studied using the generalized-gradient approximation （GG...The electronic band structures, densities of states （DOSs）, and projected densities of states （PDOSs） of the wurtzite In1-xGaxN with x=0, 0.0625, 0.125 are studied using the generalized-gradient approximation （GGA） and GGA＋U in density functional theory. Our calculations suggest that in the case of wurtzite InN it is important to apply an on-site Hubbard correction to both the d states of indium and the p states of nitrogen in order to recover the correct energy level symmetry and obtain a reliable description of the InN band structure. The method is used to study the electronic properties of the wurtzite In1-xGaxN. The conduction band minimum （CBM） energy increases, while the valence band maximum （VBM） energy decreases with the increase of the gallium concentration. The effect leads to broadening the band gap （BG） and the valence band width （VBW）. Furthermore, the compressive strain in the crystal can cause the BG and the VBW to increase with the increase of gallium concentrations.展开更多
For the frequency range of I kHz-lOMHz, the interface state density of Ni contacts on p-GaN is studied using capacitance-voltage （C-V） and conductance-frequency-voltage （G-f-V） measurements at room temperature. To...For the frequency range of I kHz-lOMHz, the interface state density of Ni contacts on p-GaN is studied using capacitance-voltage （C-V） and conductance-frequency-voltage （G-f-V） measurements at room temperature. To obtain the real capacitance and interface state density of the Ni/p-GaN structures, the effects of the series resistance （Rs） on high-frequency （SMHz） capacitance values measured at a reverse and a forward bias are investigated. The mean interface state densities obtained from the CHF-CLF capacitance and the conductance method are 2 ×1012 e V-1 cm-2 and 0.94 × 1012 eV-1 cm-2, respectively. Furthermore, the interface state density derived from the conductance method is higher than that reported from the Ni/n-GaN in the literature, which is ascribed to a poor crystal quality and to a large defect density of the Mg-doped p-GaN.展开更多
The Papua New Guinea-Solomon(PN-SL)arc is one of the regions with active crustal motions and strong geological actions.Thus,its complex subduction system makes it an ideal laboratory for studying the initiation mechan...The Papua New Guinea-Solomon(PN-SL)arc is one of the regions with active crustal motions and strong geological actions.Thus,its complex subduction system makes it an ideal laboratory for studying the initiation mechanism of plate subduction.However,the PN-SL subduction system has not yet been sufficiently studied,and its density structure has yet to be revealed.In this paper,we used the free-air gravity data,Parker-Oldenburg density surface inversion method,and the genetic algorithm density inversion method to obtain the density structure of an approximately 1000-km-long northwest-southeast line crossing the PN-SL subduction system under the constraints of the CRUST1.0 global crustal model,onshore seismic data,and the LLNL-G3Dv3 global P-wave velocity model.The density structure shows that density differences between the plates on the two sides of the trench could play a significant role in plate subduction.展开更多
The structural, electronic and elastic properties of YCu compound in the B2 （CsCl） phase were investigated using the density functional theory （DFT） within the generalized gradient approximation （GGA）. The elect...The structural, electronic and elastic properties of YCu compound in the B2 （CsCl） phase were investigated using the density functional theory （DFT） within the generalized gradient approximation （GGA）. The electronic density of states （DOS） obtained in this way accorded weU with the results of a recent study utilizing the full-potential linearized augmented plane wave （FLAPW） method. We also found that the density of d-states at the Fermi energy was low. The calculated equilibrium properties such as lattice constant, bulk modulus and its first derivative, and the elastic constants were in good agreement with experimental and theoretical results.展开更多
In this paper, we analyze lithospheric density distribution of China and surrounding regions on the basis of 30＇ × 30＇ gravity data and 1°×1 °P-wave velodty data, Firstly, we used the empirical e...In this paper, we analyze lithospheric density distribution of China and surrounding regions on the basis of 30＇ × 30＇ gravity data and 1°×1 °P-wave velodty data, Firstly, we used the empirical equation be- tween the density and the P-wave velocity difference as the base of the initial model of the Asian lithospheric density. Secondly, we calculated the gravity anomaly, caused by the Moho discontinuity and the sedimentary layer discontinuity, by the Parker formula. Thirdly, the gravity anomaly of the spherical harmonics with 2 40 order for the anomalous body below the lithosphere is calculated based on the model of EGM96. Finally, by using Algebra Reconstruction Techniques （ART）, the inversion of 30＇ ~ 30＇ residual lithospheric Bouguer gravity anomaly caused by the lithosphere yields a rather detailed struc- tural model. The results show that the lithospheric density distribution of China and surrounding regions has a certain connection with the tectonic structure. The density is relatively high in the Philippine Sea plate, Japan Sea, the Indian plate, the Kazakhstan shield and the Western Siberia plain, whereas the Tibetan Plateau has low-density characteristics. The minimum value of density lies in the north of Philippines, in the Taiwan province and in the Ryukyu island arc.展开更多
The first-principles calculations have been performed to determine the effects of Te doping to the structural, electronic, and optical properties of Ga As NWs. The calculated formation energies show that the single Te...The first-principles calculations have been performed to determine the effects of Te doping to the structural, electronic, and optical properties of Ga As NWs. The calculated formation energies show that the single Te energetically prefers to substitute the core Ga（Ef = 0.4111 eV） under As-rich conditions of Ga As nanowires, while on surface, the single Te tends to substitute the surface As site. With increasing the Te concentration, the favorable substitution sites are 2Te–Ga–A and 3Te–Ga–D. Thus, the stability of the structure of the electronic structure and optical properties are discussed.展开更多
The zincblende ternary alloys Tl_xGa_（1-x） As（0 〈 x 〈 1） are studied by numerical analysis based on the plane wave pseudopotential method within the density functional theory and the local density approximation....The zincblende ternary alloys Tl_xGa_（1-x） As（0 〈 x 〈 1） are studied by numerical analysis based on the plane wave pseudopotential method within the density functional theory and the local density approximation. To model the alloys,16-atom supercells with the 2 × 2 × 2 dimensions are used and the dependency of the lattice parameter, bulk modulus,electronic structure, energy band gap, and optical bowing on the concentration x are analyzed. The results indicate that the ternary Tl_xGa_（1-x） As alloys have an average band gap bowing parameter of 4.48 eV for semiconductor alloys and 2.412 eV for semimetals. It is found that the band gap bowing strongly depends on composition and alloying a small Tl content with GaAs produces important modifications in the band structures of the alloys.展开更多
The longitudinal structure function with shadowing correction according to the nonlinear effects of the gluon density behavior at low x is considered. The solution of the GLR-MQ evolution equation for the gluon densit...The longitudinal structure function with shadowing correction according to the nonlinear effects of the gluon density behavior at low x is considered. The solution of the GLR-MQ evolution equation for the gluon density shows that the FL^g（x, Q2） behavior can be tamed by the singularity at low x values. Comparing our results with H1 data at R=4 GeV-1 shows that at very low x this behavior is completely tamed by taking shadowing correction into account.展开更多
Gravity anomalies across the Indian region depict most of the geological and tectonic domains of the Indian continental lithosphere,which evolved through Archean cratonic nucleation,Proterozoic accretion,Phanerozoic I...Gravity anomalies across the Indian region depict most of the geological and tectonic domains of the Indian continental lithosphere,which evolved through Archean cratonic nucleation,Proterozoic accretion,Phanerozoic India-Eurasia plate convergence,and modification through many thermal perturbations and rifting.Integrated analysis of gravity and geoid anomalies together with topographic and heat flow data led to deciphering the mechanism of isostatic compensation of topographic and geological loads,lithospheric structure,and composition.展开更多
The plane wave pseudo-potential method was used to investigate the structural, electronic, and elastic properties of Cd Se_（1-x）Te_x in the zinc blende phase. It is observed that the electronic properties are improv...The plane wave pseudo-potential method was used to investigate the structural, electronic, and elastic properties of Cd Se_（1-x）Te_x in the zinc blende phase. It is observed that the electronic properties are improved considerably by using LDA ＋ U as compared to the LDA approach. The calculated lattice constants and bulk moduli are also comparable to the experimental results. The cohesive energies for pure Cd Se and Cd Te binary and their mixed alloys are calculated. The second-order elastic constants are also calculated by the Lagrangian theory of elasticity. The elastic properties show that the studied material has a ductile nature.展开更多
The South China continental margin spans various land-sea tectonic units,including the Jiangnan orogenic belt,the Cathaysia Block,and the northern margin of the South China Sea,exhibiting significant crustal structura...The South China continental margin spans various land-sea tectonic units,including the Jiangnan orogenic belt,the Cathaysia Block,and the northern margin of the South China Sea,exhibiting significant crustal structural differences.The widespread exposure of Mesozoic granites in South China reveals extensive tectonic-magmatic activities in the region.Therefore,in-depth research into the deep structure of the South China continental margin is of great significance for understanding the tectonic evolution and resource effects of the area.This paper focuses on the South China and northern South China Sea regions,employing the Hamiltonian Monte Carlo(HMC) three-dimensional density gravity inversion method,combined with deep seismic sounding and ocean bottom seismometer data,to establish a three-dimensional density model covering the land-sea extent of the South China continental margin.The density structure reveals Moho depths of 28-48 km in the South China continent,22-28 km in the northern margin of the South China Sea,and 10-20 km in the northwestern sub-basin,with the Moho surface rising from land to sea.Based on the density characteristics of granites in the region,the possible distribution ranges of granite bodies are delineated.The results show that the bottom boundaries of the Miaoershan-Yuechengling and Zhuguangshan-Wanyangshan granite bodies extend approximately 12-15 km,while the bottom boundaries of the Fogang and Darongshan-Shiwandashan granite bodies are at depths of about 4-5 km.The crustal structure of the South China continental margin thickens from sea to land,superimposed with local crustal thinning,reflecting the complex tectonic changes of the South China continent and the comprehensive influence of multi-phase tectonic-magmatic activities.The depth distribution of large granite bodies inferred from the density structure provides a basis for exploring deep tectonic-magmatic activities and their impact on mineralization in the region.展开更多
Using the gravity/GNSS data of 318 stations observed in 2020,this paper optimizes the Bouguer and free-air gravity anomalies around the 2021 Yangbi Ms 6.4 Earthquake,inverses the lithospheric density structure of the ...Using the gravity/GNSS data of 318 stations observed in 2020,this paper optimizes the Bouguer and free-air gravity anomalies around the 2021 Yangbi Ms 6.4 Earthquake,inverses the lithospheric density structure of the focal area,and obtains the distribution of isostatic additional force borne by the lithosphere.The results show that the Bouguer gravity anomaly in western Yunnan varies from-120 to-360 m Gal.As a whole the anomalies are large in the north and small in the south,and the value in the source area of the 2021 Yangbi Ms 6.4 Earthquake is about-260 m Gal.Significant lateral differences indicates that the crust around the great earthquake does not belong to a solid and stable tectonic unit.The lithosphere in the source area is basically in equilibrium,indicating that the occurrence of the great event is not relative to the lithospheric equilibrium,but to the differential movement of the crust in the horizontal direction.In addition,we obtain the teleseismic SKS phases of 51 stations.As a whole,the polarization direction of fast wave in western Yunnan is approximately vertical to the maximum gradient change direction of regional Bouguer gravity anomaly that reflects the change of Moho.展开更多
The structure and magnetic properties of Osn （n=11～22） clusters are systematically studied by using density functional theory （DFT）. For each size, the average binding energy per atom, the second-order difference...The structure and magnetic properties of Osn （n=11～22） clusters are systematically studied by using density functional theory （DFT）. For each size, the average binding energy per atom, the second-order differences of total energies and the highest occupied molecular orbital （HOMO）–the lowest unoccupied molecular orbital （LUMO） gaps are calculated to analyze the stability of the cluster. The structures of Os14 and Os18 clusters are based on a close-packed hexagonal structure, and they have maximum stabilities, so n=14, 18 are the magic numbers. The 5d electrons play a dominant role in the chemical reaction of Osn clusters. The magnetic moments of Osn clusters are quenched around n=12, and when n=18～22 the value approximates to zero, due to the difference of electron transfer.展开更多
The atomic geometry, structure stability, electronic and magnetic properties of VSe2 were systematically investigated based on the density functional theory（DFT）. Varying from 3D to 2D four VSe2 structures, bulk 2H-...The atomic geometry, structure stability, electronic and magnetic properties of VSe2 were systematically investigated based on the density functional theory（DFT）. Varying from 3D to 2D four VSe2 structures, bulk 2H-VSe2 and 1T-VSe2, monolayer H-VSe2 and T-VSe2 are all demonstrated as thermodynamically stable by lattice dynamic calculations. More interestingly, the phase transition temperature is dramatically different due to the lattice size. Finally, owing to different crystal structures, H-VSe2 is semimetallic whereas T-VSe2 is totally metallic and also they have different magnetic moments. Our main argument is that being exfoliated from bulk to monolayer, 2H-VSe2 transforms to T-VSe2, accompanied by both semimetallic-metallic transition and dramatic magnetic moment variation. Our calculations provide a novel structure phase transition and an efficient way to modulate the electronic structure and magnetic moment of layered VSe2, which suggests potential applications as high-performance functional nanomaterial.展开更多
基金funded by the National Natural Science Foundation of China(No.42174104,No.42204089)the Hubei Provincial Natural Science Foundation of China(2022CFB350)+1 种基金the Basic Research Fund of Institute of Seismology,China Earthquake Administration(IS202326341)Open Fund ofWuhan,Gravitation and Solid Earth Tides,National Observation and Research Station(WHYWZ202108,WHYWZ202301)。
文摘Controlled by the squeezing collision between the Yangtze block and the North China block and the left movement of the Tanlu fault, the Xu-Su region developed into an arc-shaped nappe structure, and many destructive earthquakes occurred in its periphery. The geological structure of this area is complex, and there is the possibility of moderate and strong earthquakes. To further explore the crust density structure and identify the main faults and deep structural features in the Xu-Su region, based on the observed seismic data and gravity/GNSS co-site observation data, combined with the EGM2008 global gravity field model, we obtained the density of three-dimensional structure using cross gradient method joint inversion. Based on this, a geological model of the Xu-Su region was established. The results show that the crustal density anomaly amplitude within 0-25 km of the Xu-Su region ranges from-280 to 490 kg/m3, showing a zonal distribution in east-west direction and a segmented north-south direction. There are several density anomalies in the shallow(0-4 km) region at Tongshan, Huaibei, Xiayi, Woyang, etc. The density anomalies are significantly correlated with the distribution of regional faults. The density structure is divided into two large regions by Subei fault, which can be further divided along the eastwest Kouziji-Nanzhao fault and Guzhen-Huaiyuan fault. The earthquakes are obviously related to the regional fault activity and the spatial distribution of abnormal bodies. The earthquake-prone areas(5-15 km) correspond to the abnormal density mutation zone, upper uplift zone, and transformation zone near Xiaoxian, Tongshan, and Xushuanglou faults. The comprehensive results show three weak seismic activity areas in the whole region, which are located near the Huaibei, Xiaoxian, and Wohe faults. The results provide theoretical support for seismic risk analysis in this area, and these three areas should be emphasized in future seismic hazard analysis.
基金Supported by the National Basic Research Program of China under Grant Nos 2015CB921300 and 2012CB821404the National Key Research and Development Program of China under Grant Nos 2016YFA0300300 and 2016YFA0300404+1 种基金the National Natural Science Foundation of China under Grant Nos 11474323,11604372,11274368,91221102,11190022,11674326 and 91422303the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB07020000
文摘The structural features and three-dimensional nature of the charge density wave （CDW） state of the layered chalcogenide 1T-TaSe2-xTex （0≤x≤2.0） are characterized by Cs-corrected transmission electron microscopy measurements. Notable changes of both average structure and the CDW state arising from Te substitution for Se are clearly demonstrated in samples with x〉0.3. The commensurate CDW state characterized by the known star-of-David clustering in the 1T-TaSe2 crystal becomes visibly unstable with Te substitution and vanishes when x=0.3. The 1T-TaSe2-xTex （0.3≤x≤1.3） samples generally adopt a remarkable incommensurate CDW state with monoclinic distortion, which could be fundamentally in correlation with the strong qq-dependent electron-phonon coupling-induced period-lattice-distortion as identified in TaTe22. Systematic analysis demonstrates that the occurrence of superconductivity is related to the suppression of the commensurate CDW phase and the presence of discommensuration is an evident structural feature observed in the superconducting samples.
基金supported by the National Natural Science Foundation of China(No.41774091).
文摘The deformation mechanisms of the Tianshan orogenic belt(TOB)are one of the most important unresolved issues in the collision of the Indian and Eurasian plates.To better understand the lithospheric deformation of the eastern Tianshan orogenic belt,we combined the S-wave tomography and gravity data to develop a three-dimensional(3D)density model of the crust and upper mantle beneath the eastern Tianshan area.Results show that the crust of the eastern Tianshan is mainly characterized by positive density anomalies,revealing widespread subduction-related magmatism during the Paleozoic.We however have also observed extensive low-density anomalies beneath the eastern Tianshan at depths deeper than~100 km,which is likely linked to a relatively hot mantle.The most fundamental differences of the lithosphere within the eastern Tianshan occur in the uppermost mantle.The uppermost mantle layers in the Bogda Shan and Harlik Shan are relatively dense.This is likely associated with an eclogite body in the uppermost mantle.The most significant negative anomaly of the uppermost mantle is however found in the Jueluotage tectonic belt and the central Tianshan Block and is possibly associated with depleted mantle material.We suggest that these differences related to compositional changes may control the strength of the lithospheric mantle and have affected the uplift of the northern and southern segments of the eastern Tianshan after the Permian.
基金supported by the Natural Science Foundation of Hunan Province of China (Grant No. 09JJ6011)the Natural Science Foundation of Education Department of Hunan Province, China (Grant Nos. 08A055 and 07C528)
文摘We derive explicit expressions for quantum discord and classical correlation for an X structure density matrix. Based on the characteristics of the expressions, the quantum discord and the classical correlation are easily obtained and compared under different initial conditions using a novel analytical method. We explain the relationships among quantum discord, classical correlation, and entanglement, and further find that the quantum discord is not always larger than the entanglement measured by concurrence in a general two-qubit X state. The new method, which is different from previous approaches, has certain guiding significance for analysing quantum discord and classical correlation of a two-qubit X state, such as a mixed state.
基金supported by the Natural Science Foundation of China(No.40830316,40774026,40704016,40774051)the Ministry of Finance People's Republic of China(No.140102)+3 种基金China Geological Survey(No.1212010611809,1212010811033)scientific research project for public welfare from the Ministry of Land and Resources of China(No.200811021)the international co-operation project from the Ministry of Science and Technology of China(No.2006DFA21340)the Basic outlay of scientific research work from Ministry of Science and Technology of China(No.J0803)
文摘This paper presents the 3D density structure of crust in the Longmenshan range and adjacent areas, with constraints from seismic and density data. The density structure of crust shows that the immense boundary plane of density distribution in relation to the Longmeshan fault belt is extended downward to -80 km deep. This density boundary plane dips towards the northwest and crosses the Moho. With the proximity to the Longmenshan fault belt, it has a larger magnitude of undulation in the upper and middle crust levels. Density changes abruptly across Longmeshan fault belt. Seismic data show that most of the earthquakes in the Longmenshan area after the 2008 Ms8.0 Wenchuan Earthquake occurred within the upper to middle crust. These earthquakes are clearly distributed in the uplifted region of the basement. A few of them occurs in the transitional zone between the uplifted and subsided areas. But most of the earthquakes distributes in transitional zone from subsided to uplifted areas in the upper and middle crust where relatively large density changes occurr The 3D density structure of crust in the Longmenshan and adjacent areas can thus help us to understand the pattern of overthrusting from the standpoint of deep crust and where the earthquakes occurred.
基金supported by National Key Research and Development Program of China (Grant No. 2016YFC0600501)National Basic Research Program of China (Grant No. 2015CB452605)+2 种基金National Natural Science Foundation of China (Grant Nos. 41702075 and 41572315)Geological Survey Project of China (Grant No. DD20160045)the State Key Program of National Natural Science of China (Grant No. 41430320)
文摘To determine the lateral and vertical variations in crustal structure and their influence on the seismicity of the Western North China Craton,the Trans-North China Orogen,and the surrounding regions,the wavelet multi-scale structures,Moho depth,crustal density structures,and isostatic state are modelled using Bouguer gravity anomaly data,topography,and earthquake focal mechanisms.We obtained homogeneous crustal densities and deviations of<1 km between the crustal thicknesses estimated from the isostatic model and those inverted from the Bouguer gravity anomalies in the Ordos Block,the Inner Mongolia Suture Zone,the Sichuan Basin,and the Jizhong Depression.These results provide new evidence for relatively simple and stable continental crustal structures,and indicate that these regions will remain stable in both the vertical and lateral directions.The Hetao Graben,Yinchuan Graben,Weihe Basin,and Shanxi graben system have heterogeneous crustal densities and are isostatically over-compensated.In contrast,the crust beneath the Yinshan Uplift,Lvliang Uplift,and northern and central Taihang Uplift is thin and under-compensated.The heterogeneous crustal densities and non-isostatic state beneath the Tibetan Plateau and Qinling Central China Orogen indicate that these two blocks are unstable in the vertical and lateral directions.Although Cenozoic deformation of the North China Craton is thought to be driven by lithospheric stresses related to the India-Eurasia collision and Pacific slab retreat in South East Asia,we suggest that gravitational potential energy created by the heterogeneous crustal structure modulates these first-order forces.The results of this study could constrain the causes of seismicity in systems surrounding the Ordos Block.
基金Project supported by the National Natural Science Foundation of China(Grant No.50971094)the Natural Science Foundation of Beijing,China(Grant Nos.KZ201310028032 and 1092007)the Domestic Visiting Program for the Graduate Students of Inner Mongolia University,China
文摘The electronic band structures, densities of states （DOSs）, and projected densities of states （PDOSs） of the wurtzite In1-xGaxN with x=0, 0.0625, 0.125 are studied using the generalized-gradient approximation （GGA） and GGA＋U in density functional theory. Our calculations suggest that in the case of wurtzite InN it is important to apply an on-site Hubbard correction to both the d states of indium and the p states of nitrogen in order to recover the correct energy level symmetry and obtain a reliable description of the InN band structure. The method is used to study the electronic properties of the wurtzite In1-xGaxN. The conduction band minimum （CBM） energy increases, while the valence band maximum （VBM） energy decreases with the increase of the gallium concentration. The effect leads to broadening the band gap （BG） and the valence band width （VBW）. Furthermore, the compressive strain in the crystal can cause the BG and the VBW to increase with the increase of gallium concentrations.
基金Supported by the Natural Science Foundation of Jiangxi Province under Grant No 20133ACB20005the Key Program of National Natural Science Foundation of China under Grant No 41330318+3 种基金the Key Program of Science and Technology Research of Ministry of Education under Grant No NRE1515the Foundation of Training Academic and Technical Leaders for Main Majors of Jiangxi Province under Grant No 20142BCB22006the Research Foundation of Education Bureau of Jiangxi Province under Grant No GJJ14501the Engineering Research Center of Nuclear Technology Application(East China Institute of Technology)Ministry of Education under Grant NoHJSJYB2016-1
文摘For the frequency range of I kHz-lOMHz, the interface state density of Ni contacts on p-GaN is studied using capacitance-voltage （C-V） and conductance-frequency-voltage （G-f-V） measurements at room temperature. To obtain the real capacitance and interface state density of the Ni/p-GaN structures, the effects of the series resistance （Rs） on high-frequency （SMHz） capacitance values measured at a reverse and a forward bias are investigated. The mean interface state densities obtained from the CHF-CLF capacitance and the conductance method are 2 ×1012 e V-1 cm-2 and 0.94 × 1012 eV-1 cm-2, respectively. Furthermore, the interface state density derived from the conductance method is higher than that reported from the Ni/n-GaN in the literature, which is ascribed to a poor crystal quality and to a large defect density of the Mg-doped p-GaN.
基金the National Natural Science Foundation of China(Nos.91858215,42076224)。
文摘The Papua New Guinea-Solomon(PN-SL)arc is one of the regions with active crustal motions and strong geological actions.Thus,its complex subduction system makes it an ideal laboratory for studying the initiation mechanism of plate subduction.However,the PN-SL subduction system has not yet been sufficiently studied,and its density structure has yet to be revealed.In this paper,we used the free-air gravity data,Parker-Oldenburg density surface inversion method,and the genetic algorithm density inversion method to obtain the density structure of an approximately 1000-km-long northwest-southeast line crossing the PN-SL subduction system under the constraints of the CRUST1.0 global crustal model,onshore seismic data,and the LLNL-G3Dv3 global P-wave velocity model.The density structure shows that density differences between the plates on the two sides of the trench could play a significant role in plate subduction.
基金supported by Gazi University Research Project Unit (05/2007/18)Hacettepe University (0701602005)
文摘The structural, electronic and elastic properties of YCu compound in the B2 （CsCl） phase were investigated using the density functional theory （DFT） within the generalized gradient approximation （GGA）. The electronic density of states （DOS） obtained in this way accorded weU with the results of a recent study utilizing the full-potential linearized augmented plane wave （FLAPW） method. We also found that the density of d-states at the Fermi energy was low. The calculated equilibrium properties such as lattice constant, bulk modulus and its first derivative, and the elastic constants were in good agreement with experimental and theoretical results.
基金supported by Project SinoProbe-02: Experiment and Integration of Deep Probe Techniques in ChinaNational Natural Science Foundation of China (NSFC, Grant No. 40874067)the Research Fund for the Doctoral Program of Higher Education (Grant No. 20070491520)
文摘In this paper, we analyze lithospheric density distribution of China and surrounding regions on the basis of 30＇ × 30＇ gravity data and 1°×1 °P-wave velodty data, Firstly, we used the empirical equation be- tween the density and the P-wave velocity difference as the base of the initial model of the Asian lithospheric density. Secondly, we calculated the gravity anomaly, caused by the Moho discontinuity and the sedimentary layer discontinuity, by the Parker formula. Thirdly, the gravity anomaly of the spherical harmonics with 2 40 order for the anomalous body below the lithosphere is calculated based on the model of EGM96. Finally, by using Algebra Reconstruction Techniques （ART）, the inversion of 30＇ ~ 30＇ residual lithospheric Bouguer gravity anomaly caused by the lithosphere yields a rather detailed struc- tural model. The results show that the lithospheric density distribution of China and surrounding regions has a certain connection with the tectonic structure. The density is relatively high in the Philippine Sea plate, Japan Sea, the Indian plate, the Kazakhstan shield and the Western Siberia plain, whereas the Tibetan Plateau has low-density characteristics. The minimum value of density lies in the north of Philippines, in the Taiwan province and in the Ryukyu island arc.
基金supported by the Open Fund of State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications,China,No.2012LF1003)the Research Foundation of Education Bureau of Sichuan Province(No.16ZA0316)
文摘The first-principles calculations have been performed to determine the effects of Te doping to the structural, electronic, and optical properties of Ga As NWs. The calculated formation energies show that the single Te energetically prefers to substitute the core Ga（Ef = 0.4111 eV） under As-rich conditions of Ga As nanowires, while on surface, the single Te tends to substitute the surface As site. With increasing the Te concentration, the favorable substitution sites are 2Te–Ga–A and 3Te–Ga–D. Thus, the stability of the structure of the electronic structure and optical properties are discussed.
文摘The zincblende ternary alloys Tl_xGa_（1-x） As（0 〈 x 〈 1） are studied by numerical analysis based on the plane wave pseudopotential method within the density functional theory and the local density approximation. To model the alloys,16-atom supercells with the 2 × 2 × 2 dimensions are used and the dependency of the lattice parameter, bulk modulus,electronic structure, energy band gap, and optical bowing on the concentration x are analyzed. The results indicate that the ternary Tl_xGa_（1-x） As alloys have an average band gap bowing parameter of 4.48 eV for semiconductor alloys and 2.412 eV for semimetals. It is found that the band gap bowing strongly depends on composition and alloying a small Tl content with GaAs produces important modifications in the band structures of the alloys.
文摘The longitudinal structure function with shadowing correction according to the nonlinear effects of the gluon density behavior at low x is considered. The solution of the GLR-MQ evolution equation for the gluon density shows that the FL^g（x, Q2） behavior can be tamed by the singularity at low x values. Comparing our results with H1 data at R=4 GeV-1 shows that at very low x this behavior is completely tamed by taking shadowing correction into account.
文摘Gravity anomalies across the Indian region depict most of the geological and tectonic domains of the Indian continental lithosphere,which evolved through Archean cratonic nucleation,Proterozoic accretion,Phanerozoic India-Eurasia plate convergence,and modification through many thermal perturbations and rifting.Integrated analysis of gravity and geoid anomalies together with topographic and heat flow data led to deciphering the mechanism of isostatic compensation of topographic and geological loads,lithospheric structure,and composition.
文摘The plane wave pseudo-potential method was used to investigate the structural, electronic, and elastic properties of Cd Se_（1-x）Te_x in the zinc blende phase. It is observed that the electronic properties are improved considerably by using LDA ＋ U as compared to the LDA approach. The calculated lattice constants and bulk moduli are also comparable to the experimental results. The cohesive energies for pure Cd Se and Cd Te binary and their mixed alloys are calculated. The second-order elastic constants are also calculated by the Lagrangian theory of elasticity. The elastic properties show that the studied material has a ductile nature.
基金supported by the National Natural Science Foundation of China (Grant No.42074092)Project of Stable Support for Youth Team in Basic Research Field,Chinese Academy of Sciences (Grant No.YSBR-020)。
文摘The South China continental margin spans various land-sea tectonic units,including the Jiangnan orogenic belt,the Cathaysia Block,and the northern margin of the South China Sea,exhibiting significant crustal structural differences.The widespread exposure of Mesozoic granites in South China reveals extensive tectonic-magmatic activities in the region.Therefore,in-depth research into the deep structure of the South China continental margin is of great significance for understanding the tectonic evolution and resource effects of the area.This paper focuses on the South China and northern South China Sea regions,employing the Hamiltonian Monte Carlo(HMC) three-dimensional density gravity inversion method,combined with deep seismic sounding and ocean bottom seismometer data,to establish a three-dimensional density model covering the land-sea extent of the South China continental margin.The density structure reveals Moho depths of 28-48 km in the South China continent,22-28 km in the northern margin of the South China Sea,and 10-20 km in the northwestern sub-basin,with the Moho surface rising from land to sea.Based on the density characteristics of granites in the region,the possible distribution ranges of granite bodies are delineated.The results show that the bottom boundaries of the Miaoershan-Yuechengling and Zhuguangshan-Wanyangshan granite bodies extend approximately 12-15 km,while the bottom boundaries of the Fogang and Darongshan-Shiwandashan granite bodies are at depths of about 4-5 km.The crustal structure of the South China continental margin thickens from sea to land,superimposed with local crustal thinning,reflecting the complex tectonic changes of the South China continent and the comprehensive influence of multi-phase tectonic-magmatic activities.The depth distribution of large granite bodies inferred from the density structure provides a basis for exploring deep tectonic-magmatic activities and their impact on mineralization in the region.
基金financially supported by the National Natural Science Foundation of China (Nos.42274008,U1839208)the National Key R&D Program of China (No.2018YFC1503704)。
文摘Using the gravity/GNSS data of 318 stations observed in 2020,this paper optimizes the Bouguer and free-air gravity anomalies around the 2021 Yangbi Ms 6.4 Earthquake,inverses the lithospheric density structure of the focal area,and obtains the distribution of isostatic additional force borne by the lithosphere.The results show that the Bouguer gravity anomaly in western Yunnan varies from-120 to-360 m Gal.As a whole the anomalies are large in the north and small in the south,and the value in the source area of the 2021 Yangbi Ms 6.4 Earthquake is about-260 m Gal.Significant lateral differences indicates that the crust around the great earthquake does not belong to a solid and stable tectonic unit.The lithosphere in the source area is basically in equilibrium,indicating that the occurrence of the great event is not relative to the lithospheric equilibrium,but to the differential movement of the crust in the horizontal direction.In addition,we obtain the teleseismic SKS phases of 51 stations.As a whole,the polarization direction of fast wave in western Yunnan is approximately vertical to the maximum gradient change direction of regional Bouguer gravity anomaly that reflects the change of Moho.
基金Project supported by the National Natural Science Foundation of China(Grant No.51072072)
文摘The structure and magnetic properties of Osn （n=11～22） clusters are systematically studied by using density functional theory （DFT）. For each size, the average binding energy per atom, the second-order differences of total energies and the highest occupied molecular orbital （HOMO）–the lowest unoccupied molecular orbital （LUMO） gaps are calculated to analyze the stability of the cluster. The structures of Os14 and Os18 clusters are based on a close-packed hexagonal structure, and they have maximum stabilities, so n=14, 18 are the magic numbers. The 5d electrons play a dominant role in the chemical reaction of Osn clusters. The magnetic moments of Osn clusters are quenched around n=12, and when n=18～22 the value approximates to zero, due to the difference of electron transfer.
基金Funded by the National Natural Science Foundation of China(No.11547115)the Science Research Foundation for Ph D of Liaoning Province(No.201501091)
文摘The atomic geometry, structure stability, electronic and magnetic properties of VSe2 were systematically investigated based on the density functional theory（DFT）. Varying from 3D to 2D four VSe2 structures, bulk 2H-VSe2 and 1T-VSe2, monolayer H-VSe2 and T-VSe2 are all demonstrated as thermodynamically stable by lattice dynamic calculations. More interestingly, the phase transition temperature is dramatically different due to the lattice size. Finally, owing to different crystal structures, H-VSe2 is semimetallic whereas T-VSe2 is totally metallic and also they have different magnetic moments. Our main argument is that being exfoliated from bulk to monolayer, 2H-VSe2 transforms to T-VSe2, accompanied by both semimetallic-metallic transition and dramatic magnetic moment variation. Our calculations provide a novel structure phase transition and an efficient way to modulate the electronic structure and magnetic moment of layered VSe2, which suggests potential applications as high-performance functional nanomaterial.
