The wavelength-tunable rectangular mode-locking operation is demonstrated in an all-fiber laser based on semi- conductor saturable absorber mirror. As the dissipative soliton resonance signature, the pulse duration va...The wavelength-tunable rectangular mode-locking operation is demonstrated in an all-fiber laser based on semi- conductor saturable absorber mirror. As the dissipative soliton resonance signature, the pulse duration varies from 5SOps to 2.1 ns as a function o~ the increasing pump power. Correspondingly, the maximum pulse energy is 9.11 n3. Moreover, it is found that the wavelength tunable operation with a range of approximately 10 nm could be obtained by properly adjusting the polarization controllers. The characteristics of the rectangular pulses at different wavelengths are similar to each other. The demonstration of the wavelength tunable rectangular pulses would be beneficial to some applications for many fields such as spectroscopy and sensing research.展开更多
A method of designing an E-plane power combiner composed of two quarter-arc bent rectangular waveguides is proposed for sub-THz and THz waves. The quarter-arc bent-waveguide power combiner has a simple geometry which ...A method of designing an E-plane power combiner composed of two quarter-arc bent rectangular waveguides is proposed for sub-THz and THz waves. The quarter-arc bent-waveguide power combiner has a simple geometry which is easy to design and fabricate. By HFSS codes, the physical mechanism and performance of the power combiner are analyzed, and the relationship between the output characteristics and the structure/operating parameters is given. Simulation results show that our power combiner is suitable for the combining of two equalpower and reversed-phase signals, the bandwidth of the combiner is wide and can be adjusted by the radius of the quarter-arc, and the isolation performance of the combiner can be improved by adding thin film resistive septa at the junction of two quarter-arc bent waveguides. Meanwhile, an approximate method based on the analytic geometrical analysis is given to design this power combiner for different frequency bands.展开更多
Based on generalized variational principles, an element called MR-12 was constructed for the static and dynamic analysis of thin plates with orthogonal anisotropy. Numerical results showed that this incompatible eleme...Based on generalized variational principles, an element called MR-12 was constructed for the static and dynamic analysis of thin plates with orthogonal anisotropy. Numerical results showed that this incompatible element converges very rapidly and has good accuracy. It was demonstrated that generalized varialional principles arc useful and effective in founding incompatible clement.Moreover, element MR-12 is easy for implementation since it does not differ very much from the common rectangular element R-12 of thin plate.展开更多
A three-dimensional rigid body on the shape of a parallelepiped is modelled in order to rock on a side or a vertex of the base,in order to evaluate the seismic response of rigid blocks lying on a horizontal support.Th...A three-dimensional rigid body on the shape of a parallelepiped is modelled in order to rock on a side or a vertex of the base,in order to evaluate the seismic response of rigid blocks lying on a horizontal support.The center of mass of the body is considered as eccentric with respect to its geometric center.As seismic input,three Italian recorded accelerograms,with different spectral content,are used.The study is mainly conducted to highlight the differences between the seismic response of 2D and 3D models of rigid blocks,with the aim to understand if,in some cases,the use of the 3D model of rigid block is required to obtain safer results.In fact,the outcomes show that in some ranges of the geometrical and mechanical parameters that characterize the excitation and the body,a two-dimensional model,which is not able to consider the 3D rocking on a vertex,can provide unsafe results.In particular,it is found that the overturning process of the three-dimensional block can occur under excitations which are lower than those which overturn a corresponding two-dimensional block.展开更多
基金Supported by the National High-Technology Research and Development Program of China under Grant No 2014AA041901the NSAF Foundation of National Natural Science Foundation of China under Grant No U1330134+1 种基金the Opening Project of Shanghai Key Laboratory of All Solid-State Laser and Applied Techniques under Grant No 2012ADL02the National Natural Science Foundation of China under Grant No 61308024
文摘The wavelength-tunable rectangular mode-locking operation is demonstrated in an all-fiber laser based on semi- conductor saturable absorber mirror. As the dissipative soliton resonance signature, the pulse duration varies from 5SOps to 2.1 ns as a function o~ the increasing pump power. Correspondingly, the maximum pulse energy is 9.11 n3. Moreover, it is found that the wavelength tunable operation with a range of approximately 10 nm could be obtained by properly adjusting the polarization controllers. The characteristics of the rectangular pulses at different wavelengths are similar to each other. The demonstration of the wavelength tunable rectangular pulses would be beneficial to some applications for many fields such as spectroscopy and sensing research.
基金Supported by the National Natural Science Foundation of China under Grant No 11075032the Fundamental Research Funds for the Central Universities under Grant No ZYGX2014J033
文摘A method of designing an E-plane power combiner composed of two quarter-arc bent rectangular waveguides is proposed for sub-THz and THz waves. The quarter-arc bent-waveguide power combiner has a simple geometry which is easy to design and fabricate. By HFSS codes, the physical mechanism and performance of the power combiner are analyzed, and the relationship between the output characteristics and the structure/operating parameters is given. Simulation results show that our power combiner is suitable for the combining of two equalpower and reversed-phase signals, the bandwidth of the combiner is wide and can be adjusted by the radius of the quarter-arc, and the isolation performance of the combiner can be improved by adding thin film resistive septa at the junction of two quarter-arc bent waveguides. Meanwhile, an approximate method based on the analytic geometrical analysis is given to design this power combiner for different frequency bands.
文摘Based on generalized variational principles, an element called MR-12 was constructed for the static and dynamic analysis of thin plates with orthogonal anisotropy. Numerical results showed that this incompatible element converges very rapidly and has good accuracy. It was demonstrated that generalized varialional principles arc useful and effective in founding incompatible clement.Moreover, element MR-12 is easy for implementation since it does not differ very much from the common rectangular element R-12 of thin plate.
基金partially funded by FY 2009-2010 PRIN–Italian Ministry for Research
文摘A three-dimensional rigid body on the shape of a parallelepiped is modelled in order to rock on a side or a vertex of the base,in order to evaluate the seismic response of rigid blocks lying on a horizontal support.The center of mass of the body is considered as eccentric with respect to its geometric center.As seismic input,three Italian recorded accelerograms,with different spectral content,are used.The study is mainly conducted to highlight the differences between the seismic response of 2D and 3D models of rigid blocks,with the aim to understand if,in some cases,the use of the 3D model of rigid block is required to obtain safer results.In fact,the outcomes show that in some ranges of the geometrical and mechanical parameters that characterize the excitation and the body,a two-dimensional model,which is not able to consider the 3D rocking on a vertex,can provide unsafe results.In particular,it is found that the overturning process of the three-dimensional block can occur under excitations which are lower than those which overturn a corresponding two-dimensional block.
