In this letter, a new moment method using helical segments is presented to model Normal Mode Helical Antenna (NMHA). Using this method, the NMHA can be modeled by a few segments. The current distributions and radiatio...In this letter, a new moment method using helical segments is presented to model Normal Mode Helical Antenna (NMHA). Using this method, the NMHA can be modeled by a few segments. The current distributions and radiation patterns of some NMHAs are calculated.A comparison is made between results obtained using this helical segment algorithm and a linear segment algorithm, and the results of the two algorithms agree fairly well. When calculating the impedance matrix [Z], all the elements of the matrix can be obtained by only calculating a few elements with the application of the symmetric and periodic characteristics of the NMHA.Therefore, the CPU time and the memory storage are significantly reduced, with the accuracy and speed enhanced.展开更多
The present investigation deals with the 2-dimensional deformation in a homogeneous thermoelastic solid with voids subjected to inclined loads.The heat conduction equation is affected with the Thomson coefficient.The ...The present investigation deals with the 2-dimensional deformation in a homogeneous thermoelastic solid with voids subjected to inclined loads.The heat conduction equation is affected with the Thomson coefficient.The basic governing equations are modified by using Green-Naghdi theory of type-III.The normal mode analysis technique is used to obtain the components of stress,strain,temperature,induced magnetic field and change in volume fraction field.The variations of these quantities have been depicted graphically in the Green-Naghdi theories of type-II and III for an insulated boundary.From numerical calculations,the effect of Thomson parameter and angle of inclination on a homogeneous,isotropic,electro-magneto-thermoelastic material with voids is revealed and discussed.展开更多
By using the quasiclassical trajectory method,changes of normal and local mode vibrational excitation energies with time are investigated for XH_4 (X=C,Si,Ge) molecules.The results demonstrate that in a CH_4 molecule ...By using the quasiclassical trajectory method,changes of normal and local mode vibrational excitation energies with time are investigated for XH_4 (X=C,Si,Ge) molecules.The results demonstrate that in a CH_4 molecule the coupling between C—H stretching vibration and H—C—H bending vibration is relative- ly large so that the energy transfer is fast;while in SiH_4 or GeH_4 molecules this coupling is relatively small and thus an obvious energy relaxation is observed.This implies that there exists approximate local mode vibrations for certain vibrational excitation states.展开更多
The purpose of this paper is to study the effect of rotation on the general three-dimensional model of the equations of the generalized thermoelasticity for a homogeneous isotropic elastic half-space solid. The proble...The purpose of this paper is to study the effect of rotation on the general three-dimensional model of the equations of the generalized thermoelasticity for a homogeneous isotropic elastic half-space solid. The problem is studied in the context of the Green-Naghdi theory of type II (without energy dissipation). The normal mode analysis is used to obtain the expressions for the temperature, thermal stress, strain and displacement. The distributions of variables considered are represented graphically.展开更多
In this paper we introduce the effect of initial stress on a magneto-thermoe- lastic functionally graded material (FGM) with Green Naghdi theory with energy dissipation. A system of PDE was obtained. The normal mode a...In this paper we introduce the effect of initial stress on a magneto-thermoe- lastic functionally graded material (FGM) with Green Naghdi theory with energy dissipation. A system of PDE was obtained. The normal mode analysis method is used to convert these equations into ODE and get the analytical solution to write expressions for displacements, temperatures, stresses. Some comparisons carried out to view the initial stress influence on the field variables. Numerical results are graphed to view the influence of initial stress. Some particular cases are deduced in this study.展开更多
文摘In this letter, a new moment method using helical segments is presented to model Normal Mode Helical Antenna (NMHA). Using this method, the NMHA can be modeled by a few segments. The current distributions and radiation patterns of some NMHAs are calculated.A comparison is made between results obtained using this helical segment algorithm and a linear segment algorithm, and the results of the two algorithms agree fairly well. When calculating the impedance matrix [Z], all the elements of the matrix can be obtained by only calculating a few elements with the application of the symmetric and periodic characteristics of the NMHA.Therefore, the CPU time and the memory storage are significantly reduced, with the accuracy and speed enhanced.
文摘The present investigation deals with the 2-dimensional deformation in a homogeneous thermoelastic solid with voids subjected to inclined loads.The heat conduction equation is affected with the Thomson coefficient.The basic governing equations are modified by using Green-Naghdi theory of type-III.The normal mode analysis technique is used to obtain the components of stress,strain,temperature,induced magnetic field and change in volume fraction field.The variations of these quantities have been depicted graphically in the Green-Naghdi theories of type-II and III for an insulated boundary.From numerical calculations,the effect of Thomson parameter and angle of inclination on a homogeneous,isotropic,electro-magneto-thermoelastic material with voids is revealed and discussed.
基金the National Natural Science Foundation of Chinathe State Education Commission Science Foundation
文摘By using the quasiclassical trajectory method,changes of normal and local mode vibrational excitation energies with time are investigated for XH_4 (X=C,Si,Ge) molecules.The results demonstrate that in a CH_4 molecule the coupling between C—H stretching vibration and H—C—H bending vibration is relative- ly large so that the energy transfer is fast;while in SiH_4 or GeH_4 molecules this coupling is relatively small and thus an obvious energy relaxation is observed.This implies that there exists approximate local mode vibrations for certain vibrational excitation states.
文摘The purpose of this paper is to study the effect of rotation on the general three-dimensional model of the equations of the generalized thermoelasticity for a homogeneous isotropic elastic half-space solid. The problem is studied in the context of the Green-Naghdi theory of type II (without energy dissipation). The normal mode analysis is used to obtain the expressions for the temperature, thermal stress, strain and displacement. The distributions of variables considered are represented graphically.
文摘In this paper we introduce the effect of initial stress on a magneto-thermoe- lastic functionally graded material (FGM) with Green Naghdi theory with energy dissipation. A system of PDE was obtained. The normal mode analysis method is used to convert these equations into ODE and get the analytical solution to write expressions for displacements, temperatures, stresses. Some comparisons carried out to view the initial stress influence on the field variables. Numerical results are graphed to view the influence of initial stress. Some particular cases are deduced in this study.
