The instabilities of gyrotron, gyro-peniotron and cyclotron auto-resonance masers(CARM) and their relationship are analysed in detail. By introducing gyrokinetic variablesin the Vlasov equation, a unified description,...The instabilities of gyrotron, gyro-peniotron and cyclotron auto-resonance masers(CARM) and their relationship are analysed in detail. By introducing gyrokinetic variablesin the Vlasov equation, a unified description, i.e. the gyrokinetics, of these free-electronmasersisgiven.展开更多
A new method is proposed to enhance the efficiency of free-electron maser (EM). Aradial electrostatic field is introduced to assist the axial magnetic field to focus a large-orbitclectron beam. A new kind of azimuthal...A new method is proposed to enhance the efficiency of free-electron maser (EM). Aradial electrostatic field is introduced to assist the axial magnetic field to focus a large-orbitclectron beam. A new kind of azimuthal bunching mechanism. caused by the angular-momentum effect, is demonstrated. Nonlinear simulation of the interaction between a rela-tivistic electron beam and TE_(5,1,1) mode or TE_(10,1,1) mode shows that, as long as the initialparameters are properly chosen, the method is valid.展开更多
With the consideration of slip deformation mechanism and various slip systems of body centered cubic （BCC） metals, Taylor-type and finite element polycrystal models were embedded into the commercial finite element c...With the consideration of slip deformation mechanism and various slip systems of body centered cubic （BCC） metals, Taylor-type and finite element polycrystal models were embedded into the commercial finite element code ABAQUS to realize crystal plasticity finite element modeling, based on the rate dependent crystal constitutive equations. Initial orientations measured by electron backscatter diffraction （EBSD） were directly input into the crystal plasticity finite element model to simulate the develop- ment of rolling texture of interstitial-free steel （IF steel） at various reductions. The modeled results show a good agreement with the experimental results. With increasing reduction, the predicted and experimental rolling textures tend to sharper, and the results simulated by the Taylor-type model are stronger than those simulated by finite element model.＇Conclusions are obtained that rolling textures calculated with 48 { 110} 〈 111 〉＋ { 112 } 〈 111〉＋ { 123 } 〈 111 〉 slip systems are more approximate to EBSD results.展开更多
文摘The instabilities of gyrotron, gyro-peniotron and cyclotron auto-resonance masers(CARM) and their relationship are analysed in detail. By introducing gyrokinetic variablesin the Vlasov equation, a unified description, i.e. the gyrokinetics, of these free-electronmasersisgiven.
文摘A new method is proposed to enhance the efficiency of free-electron maser (EM). Aradial electrostatic field is introduced to assist the axial magnetic field to focus a large-orbitclectron beam. A new kind of azimuthal bunching mechanism. caused by the angular-momentum effect, is demonstrated. Nonlinear simulation of the interaction between a rela-tivistic electron beam and TE_(5,1,1) mode or TE_(10,1,1) mode shows that, as long as the initialparameters are properly chosen, the method is valid.
文摘With the consideration of slip deformation mechanism and various slip systems of body centered cubic （BCC） metals, Taylor-type and finite element polycrystal models were embedded into the commercial finite element code ABAQUS to realize crystal plasticity finite element modeling, based on the rate dependent crystal constitutive equations. Initial orientations measured by electron backscatter diffraction （EBSD） were directly input into the crystal plasticity finite element model to simulate the develop- ment of rolling texture of interstitial-free steel （IF steel） at various reductions. The modeled results show a good agreement with the experimental results. With increasing reduction, the predicted and experimental rolling textures tend to sharper, and the results simulated by the Taylor-type model are stronger than those simulated by finite element model.＇Conclusions are obtained that rolling textures calculated with 48 { 110} 〈 111 〉＋ { 112 } 〈 111〉＋ { 123 } 〈 111 〉 slip systems are more approximate to EBSD results.
