Defect engineering is a commonly methodology used to enhance the thermoelectric performance of thermoelectric PbTe by improving its electronic transport properties.At the nanoscale,defects can induce quantum tunneling...Defect engineering is a commonly methodology used to enhance the thermoelectric performance of thermoelectric PbTe by improving its electronic transport properties.At the nanoscale,defects can induce quantum tunneling effects that significantly impact the electrical properties of materials.To understand the specific mechanisms underlying the quantum transport properties of PbTe,we employ the non-equilibrium Green's function(NEGF)method to investigate the effects of intrinsic defects(point defects and grain boundaries)on the electronic transport properties of PbTe-based nanodevices from a quantum mechanical perspective.Our results show that the Pb vacancy(VPb)has the highest conduction.The conduction depends on the defect type,chemical potential and bias voltage.The presence of intrinsic point defects introduces impurity levels,facilitating the electron tunneling and leading to an increase in the transmission coefficient,thereby enhancing the electronic transport properties.For PbTe containing grain boundaries,these boundaries suppress the electronic transport properties.The Te occupied twin boundary(Te-TB)exerts a stronger inhibitory effect than the Pb occupied twin boundary(Pb-TB).Nevertheless,the combined effect between twin boundaries and point defects can enhance the electrical properties.Therefore,in order to obtain highly conductive of PbTe materials,a Te-rich synthesis environment should be used to promote the effective formation of Pb vacancy.Our work offers a comprehensive understanding of the impact of defects on electron scattering in thermoelectric materials.展开更多
Understanding the effects of point liquid loading on transversely isotropic poroelastic media is crucial for advancing geomechanics and biomechanics, where precise modeling of fluid-structure interactions is essential...Understanding the effects of point liquid loading on transversely isotropic poroelastic media is crucial for advancing geomechanics and biomechanics, where precise modeling of fluid-structure interactions is essential. This paper presents a comprehensive analysis of infinite transversely isotropic poroelasticity under a fluid source, based on Biot's theory, aiming to uncover new and previously unexplored insights in the literature. We begin our study by deriving a general solution for fluid-saturated, transversely isotropic poroelastic materials in terms of harmonic functions that satisfy sixth-order homogeneous partial differential equations, using potential theory and Almansi's theorem. Based on these general solutions and potential functions, we construct a Green's function for a point fluid source, introducing three new harmonic functions with undetermined constants. These constants are determined by enforcing continuity and equilibrium conditions. Substituting these into the general solution yields fundamental solutions for poroelasticity that provide crucial support for a wide range of project problems. Numerical results and comparisons with existing literature are provided to illustrate physical mechanisms through contour plots. Our observations reveal that all components tend to zero in the far field and become singular at the concentrated source. Additionally, the contours exhibit rapid changes near the point fluid source but display gradual variations at a distance from it. These findings highlight the intricate behavior of the system under point liquid loading, offering valuable insights for further research and practical applications.展开更多
In this paper,we study a class of Sturm-Liouville problems,where the boundary conditions involve eigenparameters.Firstly,by defining a new inner product which depends on the transmission conditions,we obtain a new Hil...In this paper,we study a class of Sturm-Liouville problems,where the boundary conditions involve eigenparameters.Firstly,by defining a new inner product which depends on the transmission conditions,we obtain a new Hilbert space,on which the concerned operator A is self-adjoint.Then we construct the fundamental solutions to the problem,obtain the necessary and sufficient conditions for eigenvalues,and prove that the eigenvalues are simple.Finally,we investigate Green’s functions of such problem.展开更多
We present a method to unify the calculation of Green＇s functions for an electromagnetic（EM） transmitting source embedded in a homogeneous stratified medium.A virtual interface parallel to layer interfaces is intro...We present a method to unify the calculation of Green＇s functions for an electromagnetic（EM） transmitting source embedded in a homogeneous stratified medium.A virtual interface parallel to layer interfaces is introduced through the source location.The potentials for Green＇s function are derived by decomposing the partial wave solutions to Helmholtz＇s equations into upward and downward within boundaries.The amplitudes of the potentials in each stratum are obtained recursively from the initial amplitudes at the source level.The initial amplitudes are derived by coupling with the transmitting sources and following the discontinuity of the tangential electric and magnetic fields at the source interface.Only the initial terms are related to the transmitting sources and thus need to be modified for different transmitters,whereas the kernel connected with the stratified media stays unchanged.Hence,the present method can be easily applied to EM transmitting sources with little modification.The application of the proposed method to the marine controlled-source electromagnetic method（MCSEM） demonstrates its simplicity and flexibility.展开更多
By using integral transform methods, the Green(s functions of horizontal harmonic force applied at the interior of the saturated half-space soil are obtained in the paper. The general solutions of the Biot dynamic equ...By using integral transform methods, the Green(s functions of horizontal harmonic force applied at the interior of the saturated half-space soil are obtained in the paper. The general solutions of the Biot dynamic equations in frequency domain are established through the use of Hankel integral transforms technique. Utilizing the above- mentioned general solutions, and the boundary conditions of the surface of the half-space and the continuous conditions at the plane of the horizontal force, the solutions of the boundary value problem can be determined. By the numerical inverse Hankel transforms method, the Green(s functions of the harmonic horizontal force are obtainable. The degenerate case of the results deduced from this paper agrees well with the known results. Two numerical examples are given in the paper.展开更多
在硬件在回路仿真系统中,模型需与数据采集卡之间进行实时数据的采集和交换,Simulink下Real Time Workspace工具箱提供了与硬件之间的实时数据采集和交换,但是工具箱并不支持市面上所有采集板卡的类型,给用户对采集板卡选型带来一定局...在硬件在回路仿真系统中,模型需与数据采集卡之间进行实时数据的采集和交换,Simulink下Real Time Workspace工具箱提供了与硬件之间的实时数据采集和交换,但是工具箱并不支持市面上所有采集板卡的类型,给用户对采集板卡选型带来一定局限性。因此本文使用Simulink中S-Function模块编写不同采集板卡的硬件驱动,证明只要是数据采集工具箱支持的板卡型号,都可以用S-Function进行模块化硬件驱动编写,解决了Simulink中Real Time Workspace工具箱给用户在使用Simulink建模过程中对板卡选型的局限性这一问题。展开更多
s Western Yunnan is located at the boundary of collision or underthrusting zone of Eurasian plate and is influenced by many times tectonic movements. With very complex geological environment and tectonic background, i...s Western Yunnan is located at the boundary of collision or underthrusting zone of Eurasian plate and is influenced by many times tectonic movements. With very complex geological environment and tectonic background, it is one of the seismically active areas. In the paper, the teleseismic records were selected from 16 national, local and mo-bile stations, including 4 very-wide-band mobile stations of PASSCAL. And nearly 2 000 receiver functions were extracted. Two measuring lines are 650 km and 450 km, respectively and across some major tectonic units in Western Yunnan. It is indicated that Nujiang might be a seam characterized by underthrusting. The western and eastern boundaries of Sichuan-Yunnan rhombus block, i.e., Honghe and Xiaojiang faults, might be an erection seam or collision belt. Panxi tectonic zone still has the characteristics of continental rift valley, that is, the surface is hollow and the upper mantle is upwarping. The tectonic situation in Western Yunnan is of certain regulation with the interlacing distribution of orogenic zone and seam. The crustal thickness decreases gradually from the north to the south and the S wave velocity is globally lower here.展开更多
基金financial support from the National Natural Science Foundation of China(No.12474016)the program of“Distinguished Expert of Taishan Scholar”(No.tstp20221124)+4 种基金the National Natural Science Foundation of China(Nos.52172212,12474017)the Shandong Provincial Science Foundation(ZR2021YQ03)the program for“Young Scientists of Taishan Scholars”(No.tsqn202306184)financial support from the National Natural Science Foundation of China(No.12464034)the Natural Science Foundation of Ningxia,China(No.2024AAC05070)。
文摘Defect engineering is a commonly methodology used to enhance the thermoelectric performance of thermoelectric PbTe by improving its electronic transport properties.At the nanoscale,defects can induce quantum tunneling effects that significantly impact the electrical properties of materials.To understand the specific mechanisms underlying the quantum transport properties of PbTe,we employ the non-equilibrium Green's function(NEGF)method to investigate the effects of intrinsic defects(point defects and grain boundaries)on the electronic transport properties of PbTe-based nanodevices from a quantum mechanical perspective.Our results show that the Pb vacancy(VPb)has the highest conduction.The conduction depends on the defect type,chemical potential and bias voltage.The presence of intrinsic point defects introduces impurity levels,facilitating the electron tunneling and leading to an increase in the transmission coefficient,thereby enhancing the electronic transport properties.For PbTe containing grain boundaries,these boundaries suppress the electronic transport properties.The Te occupied twin boundary(Te-TB)exerts a stronger inhibitory effect than the Pb occupied twin boundary(Pb-TB).Nevertheless,the combined effect between twin boundaries and point defects can enhance the electrical properties.Therefore,in order to obtain highly conductive of PbTe materials,a Te-rich synthesis environment should be used to promote the effective formation of Pb vacancy.Our work offers a comprehensive understanding of the impact of defects on electron scattering in thermoelectric materials.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12272269, 11972257,11832014 and 11472193)the Shanghai Pilot Program for Basic Researchthe Shanghai Gaofeng Project for University Academic Program Development。
文摘Understanding the effects of point liquid loading on transversely isotropic poroelastic media is crucial for advancing geomechanics and biomechanics, where precise modeling of fluid-structure interactions is essential. This paper presents a comprehensive analysis of infinite transversely isotropic poroelasticity under a fluid source, based on Biot's theory, aiming to uncover new and previously unexplored insights in the literature. We begin our study by deriving a general solution for fluid-saturated, transversely isotropic poroelastic materials in terms of harmonic functions that satisfy sixth-order homogeneous partial differential equations, using potential theory and Almansi's theorem. Based on these general solutions and potential functions, we construct a Green's function for a point fluid source, introducing three new harmonic functions with undetermined constants. These constants are determined by enforcing continuity and equilibrium conditions. Substituting these into the general solution yields fundamental solutions for poroelasticity that provide crucial support for a wide range of project problems. Numerical results and comparisons with existing literature are provided to illustrate physical mechanisms through contour plots. Our observations reveal that all components tend to zero in the far field and become singular at the concentrated source. Additionally, the contours exhibit rapid changes near the point fluid source but display gradual variations at a distance from it. These findings highlight the intricate behavior of the system under point liquid loading, offering valuable insights for further research and practical applications.
基金supported by the National Natural Science Foundation of China(No.12461086)the Natural Science Foundation of Hubei Province(No.2022CFC016)。
文摘In this paper,we study a class of Sturm-Liouville problems,where the boundary conditions involve eigenparameters.Firstly,by defining a new inner product which depends on the transmission conditions,we obtain a new Hilbert space,on which the concerned operator A is self-adjoint.Then we construct the fundamental solutions to the problem,obtain the necessary and sufficient conditions for eigenvalues,and prove that the eigenvalues are simple.Finally,we investigate Green’s functions of such problem.
基金supported by CNSF(Granted No.40874050)Chinese High Technology Project(Granted No.2011YQ05006010)
文摘We present a method to unify the calculation of Green＇s functions for an electromagnetic（EM） transmitting source embedded in a homogeneous stratified medium.A virtual interface parallel to layer interfaces is introduced through the source location.The potentials for Green＇s function are derived by decomposing the partial wave solutions to Helmholtz＇s equations into upward and downward within boundaries.The amplitudes of the potentials in each stratum are obtained recursively from the initial amplitudes at the source level.The initial amplitudes are derived by coupling with the transmitting sources and following the discontinuity of the tangential electric and magnetic fields at the source interface.Only the initial terms are related to the transmitting sources and thus need to be modified for different transmitters,whereas the kernel connected with the stratified media stays unchanged.Hence,the present method can be easily applied to EM transmitting sources with little modification.The application of the proposed method to the marine controlled-source electromagnetic method（MCSEM） demonstrates its simplicity and flexibility.
基金State Natural Science Foundation (59879012) and Doctoral Foundation from State Education Commission (98024832).
文摘By using integral transform methods, the Green(s functions of horizontal harmonic force applied at the interior of the saturated half-space soil are obtained in the paper. The general solutions of the Biot dynamic equations in frequency domain are established through the use of Hankel integral transforms technique. Utilizing the above- mentioned general solutions, and the boundary conditions of the surface of the half-space and the continuous conditions at the plane of the horizontal force, the solutions of the boundary value problem can be determined. By the numerical inverse Hankel transforms method, the Green(s functions of the harmonic horizontal force are obtainable. The degenerate case of the results deduced from this paper agrees well with the known results. Two numerical examples are given in the paper.
文摘在硬件在回路仿真系统中,模型需与数据采集卡之间进行实时数据的采集和交换,Simulink下Real Time Workspace工具箱提供了与硬件之间的实时数据采集和交换,但是工具箱并不支持市面上所有采集板卡的类型,给用户对采集板卡选型带来一定局限性。因此本文使用Simulink中S-Function模块编写不同采集板卡的硬件驱动,证明只要是数据采集工具箱支持的板卡型号,都可以用S-Function进行模块化硬件驱动编写,解决了Simulink中Real Time Workspace工具箱给用户在使用Simulink建模过程中对板卡选型的局限性这一问题。
基金State Key Basic Research Development and Programming Project of China (G1998040700).
文摘s Western Yunnan is located at the boundary of collision or underthrusting zone of Eurasian plate and is influenced by many times tectonic movements. With very complex geological environment and tectonic background, it is one of the seismically active areas. In the paper, the teleseismic records were selected from 16 national, local and mo-bile stations, including 4 very-wide-band mobile stations of PASSCAL. And nearly 2 000 receiver functions were extracted. Two measuring lines are 650 km and 450 km, respectively and across some major tectonic units in Western Yunnan. It is indicated that Nujiang might be a seam characterized by underthrusting. The western and eastern boundaries of Sichuan-Yunnan rhombus block, i.e., Honghe and Xiaojiang faults, might be an erection seam or collision belt. Panxi tectonic zone still has the characteristics of continental rift valley, that is, the surface is hollow and the upper mantle is upwarping. The tectonic situation in Western Yunnan is of certain regulation with the interlacing distribution of orogenic zone and seam. The crustal thickness decreases gradually from the north to the south and the S wave velocity is globally lower here.
