Theoretical horizontal displacements caused by the 2004 Sumatra earthquake in the Sichuan-Yunnan area have been calculated according to a spherical dislocation theory and an earthquake-fault model. The results show th...Theoretical horizontal displacements caused by the 2004 Sumatra earthquake in the Sichuan-Yunnan area have been calculated according to a spherical dislocation theory and an earthquake-fault model. The results show that the theoretical displacements are basically consistent with the GPS observations in situ. On this basis,we have calculated the co-seismic displacements, strains, changes of gravity and geoid of the whole Earth, including China mainland and vicinity, caused by this earthquake. Key wards：展开更多
The process of tsunami evolution during its generation under the effect of the variable velocities of realistic submarine landslides based on a two-dimensional curvilinear slide model is investigated. Tsunami generati...The process of tsunami evolution during its generation under the effect of the variable velocities of realistic submarine landslides based on a two-dimensional curvilinear slide model is investigated. Tsunami generation from submarine gravity mass flows is described in three stages. The first stage represented by a rapid curvilinear down and uplift faulting with rise time. The second stage represented by a unilaterally propagation in the positive x direction to a significant length to produce curvilinear two-dimensional models represented by a depression slump, and a displaced accumulation slide model. The last stage represented by the time variation in the velocity of the accumulation slide (block slide). By using transforms method, Laplace in time and Fourier in space, tsunami waveforms within the frame of the linearized shallow water theory for constant water depth are analyzed analytically for the movable source model. Effect of the water depths on the amplification factor of the tsunami generation by the submarine slump and slide for different propagation lengths and widths has been studied and the results are plotted. Comparison of tsunami peak amplitudes is discussed for different propagation lengths, widths and water depths. In addition, we demonstrated the tsunami propagation waveforms after the slide stops moving at different propagation times.展开更多
Two-dimensional(2D)antiferromagnetic(AFM)skyrmions are free from stray magnetic field and skyrmion Hall effect,and can be driven by a small current density up to a high speed,desirable for low-power spintronic applica...Two-dimensional(2D)antiferromagnetic(AFM)skyrmions are free from stray magnetic field and skyrmion Hall effect,and can be driven by a small current density up to a high speed,desirable for low-power spintronic applications.However,most 2D AFM skyrmions are realized in complex heterostructured materials,which impedes the dense integration of spintronic devices.Here,we propose that 2D AFM skyrmions can be achieved in ruthenium tetrafluoride(RuF_(4))monolayer using hybrid functional theory combined with atomistic spin dynamics simulations.Our study indicates that 2D RuF_(4)is dynamically stable and its nondegenerate vibration modes in optical branches are either Raman or infrared active.Furthermore,2D RuF_(4)acts as an indirect bandgap semiconductor with an out-of-plane AFM state.Notably,the presence of a weak Dzyaloshinskii-Moriya interaction in 2D RuF_(4)leads to a spin spiral ground state at low temperatures,enabling the formation of AFM skyrmions with possible length modulation by an external magnetic field.Our results give insight into 2D RuF_(4)and may provide an intriguing platform for 2D AFM skyrmion-based spintronic applications.展开更多
The scattering characteristics of electromagnetic waves from buildings are presented. The uniform geometric theory of diffraction (UTD) is employed to approximate the near field-far field distribution. The numerical r...The scattering characteristics of electromagnetic waves from buildings are presented. The uniform geometric theory of diffraction (UTD) is employed to approximate the near field-far field distribution. The numerical results presented demonstrate that the UTD solution can be conveniently and efficiently applied to many practical problems. As such results are of importance to the mobile communication field.展开更多
基金supported by Basic Research Foundation from Institute of Earthquake Science,CEA(0210240101)
文摘Theoretical horizontal displacements caused by the 2004 Sumatra earthquake in the Sichuan-Yunnan area have been calculated according to a spherical dislocation theory and an earthquake-fault model. The results show that the theoretical displacements are basically consistent with the GPS observations in situ. On this basis,we have calculated the co-seismic displacements, strains, changes of gravity and geoid of the whole Earth, including China mainland and vicinity, caused by this earthquake. Key wards：
文摘The process of tsunami evolution during its generation under the effect of the variable velocities of realistic submarine landslides based on a two-dimensional curvilinear slide model is investigated. Tsunami generation from submarine gravity mass flows is described in three stages. The first stage represented by a rapid curvilinear down and uplift faulting with rise time. The second stage represented by a unilaterally propagation in the positive x direction to a significant length to produce curvilinear two-dimensional models represented by a depression slump, and a displaced accumulation slide model. The last stage represented by the time variation in the velocity of the accumulation slide (block slide). By using transforms method, Laplace in time and Fourier in space, tsunami waveforms within the frame of the linearized shallow water theory for constant water depth are analyzed analytically for the movable source model. Effect of the water depths on the amplification factor of the tsunami generation by the submarine slump and slide for different propagation lengths and widths has been studied and the results are plotted. Comparison of tsunami peak amplitudes is discussed for different propagation lengths, widths and water depths. In addition, we demonstrated the tsunami propagation waveforms after the slide stops moving at different propagation times.
基金supported by the National Key Research and Development Program of China(MOST)(2022YFA1405100)the National Natural Science Foundation of China(NSFC)(52172272)the Scientific Research Foundation of CUIT(KYTZ202172).
文摘Two-dimensional(2D)antiferromagnetic(AFM)skyrmions are free from stray magnetic field and skyrmion Hall effect,and can be driven by a small current density up to a high speed,desirable for low-power spintronic applications.However,most 2D AFM skyrmions are realized in complex heterostructured materials,which impedes the dense integration of spintronic devices.Here,we propose that 2D AFM skyrmions can be achieved in ruthenium tetrafluoride(RuF_(4))monolayer using hybrid functional theory combined with atomistic spin dynamics simulations.Our study indicates that 2D RuF_(4)is dynamically stable and its nondegenerate vibration modes in optical branches are either Raman or infrared active.Furthermore,2D RuF_(4)acts as an indirect bandgap semiconductor with an out-of-plane AFM state.Notably,the presence of a weak Dzyaloshinskii-Moriya interaction in 2D RuF_(4)leads to a spin spiral ground state at low temperatures,enabling the formation of AFM skyrmions with possible length modulation by an external magnetic field.Our results give insight into 2D RuF_(4)and may provide an intriguing platform for 2D AFM skyrmion-based spintronic applications.
文摘The scattering characteristics of electromagnetic waves from buildings are presented. The uniform geometric theory of diffraction (UTD) is employed to approximate the near field-far field distribution. The numerical results presented demonstrate that the UTD solution can be conveniently and efficiently applied to many practical problems. As such results are of importance to the mobile communication field.
