A Mach-Zehnder(MZ) electro-optic(EO) modulator are real iz ed,with three optical layers as polymer materials.The functional layer is the co rona poled crosslinkable polyurethane.The ridge waveguide is fabricated by us...A Mach-Zehnder(MZ) electro-optic(EO) modulator are real iz ed,with three optical layers as polymer materials.The functional layer is the co rona poled crosslinkable polyurethane.The ridge waveguide is fabricated by using the spin-coating,poling,photolithography and oxygen reactive ion etching(RIE) techniques.The mode and the modulation properties of these devices are demonstra ted in a micron control system,while the light source works at the wavelength of 1 31 or 1 55 micron.展开更多
An electrostatic model for the shock observed in the earth's polar region is established by deriving the 'Sagdeev potential' from the magnetohydrodynamic equations in a cylindrical coordinate system. The r...An electrostatic model for the shock observed in the earth's polar region is established by deriving the 'Sagdeev potential' from the magnetohydrodynamic equations in a cylindrical coordinate system. The results show that the shock can develop from the ion acoustic wave or ion cyclotron wave in the polar region, and can exist when the Mach number M and the initial electric field E-0 satisfy the condition of vertical bar(a/M-2-1)E(0)vertical bar = 1. Also, some features of the shock wave are discussed. The result can interpret the electrostatic shock observed in the earth's polar region.展开更多
We study behavior of an atomic wave packet in a circularly polarized electromagnetic wave, and particularly calculate the atomic inversion of the wave packet. A general method of calculation is presented. The results ...We study behavior of an atomic wave packet in a circularly polarized electromagnetic wave, and particularly calculate the atomic inversion of the wave packet. A general method of calculation is presented. The results are interesting. For example, if the wave packet is very narrow or/and the interaction is very strong, no matter the atom is initially in its ground state or excited state, the atomic inversion approaches zero as time approaches infinity. If the atom is initially in its ground state and excited state with the probability 1/2 respectively, and if the momentum density is an even function, then the atomic inversion equals zero at any time.展开更多
We study theoretically transport properties of two-dimenslonal electron gases through antiparallel magneticelectric barrier structures. Two kinds of magnetic barrier configurations are employed： one is that the stren...We study theoretically transport properties of two-dimenslonal electron gases through antiparallel magneticelectric barrier structures. Two kinds of magnetic barrier configurations are employed： one is that the strength of the double δ-functlon in opposite directions is equal and the other is that the strength is unequal Similarities and differences of electronic transports are presented. It is found that the transmission and the conductance depend strongly on the shape of the magnetic barrier and the height of the electric harrier. The results indicate that this system does not possess any spin filtering and spin polarization and electron gases can realize perfect resonant tunneling and wave-vector filtering properties. Moreover, the strength of the effect of the inhomogeneous magnetic field on the transport properties is discussed.展开更多
We theoretically investigate the wave-vector and temperature-dependent electron transport in a magneticnanostructure modulated by an applied bias.The large spin-polarization can be achieved in such a device,and the de...We theoretically investigate the wave-vector and temperature-dependent electron transport in a magneticnanostructure modulated by an applied bias.The large spin-polarization can be achieved in such a device,and the degreeof spin-polarization strongly depends on the transverse wave-vector and the temperature.These interesting propertiesmay be helpful to spin-polarize electrons into semiconductors,and this device may be used as a spin filter.展开更多
Zinc-air battery is one of the most promising next-generation energy conversion and storage systems.Green and low-cost catalysts with high oxygen reduction reaction(ORR)catalytic activity are desired to meet the requi...Zinc-air battery is one of the most promising next-generation energy conversion and storage systems.Green and low-cost catalysts with high oxygen reduction reaction(ORR)catalytic activity are desired to meet the requirements of Zinc-air batteries.Herein,poly-active centric Co3O4-CeO2/Co-N-C(ketjenblack carbon)catalysts were prepared by a facile method.The Co3O4 and CeO2 nanoparticles are uniformly anchored on the surface of Co and N doped carbon support.The half-wave potential of Co3O4-CeO2/Co-N-C in the rotating disk electrode testing is close to that of Pt/C.The Zn-air battery using Co3O4-CeO2/Co-N-C as the cathode catalyst can provide a high specific capacity of 728 mA h g^-1 at 20 mA cm^-2 and maintain a stable discharge voltage.The remarkable catalytic performance is mainly attributed to the synergistic effect among Co3O4,CeO2 and Co-N-C,the outstanding electrical conductivity and the large surface area.Benefitting from the high catalytic activity,environmental friendliness and the facile synthesis process,Co3O4-CeO2/Co-N-C catalyst lends itself well to a great prospect in the application of metalair batteries.展开更多
In the present paper the problem of nonlinear interaction of two mildly-relativistic circularly polarized lasers in a cold plasma is studied in order to investigate electromagneticaily induced transparency （EIT）. Ba...In the present paper the problem of nonlinear interaction of two mildly-relativistic circularly polarized lasers in a cold plasma is studied in order to investigate electromagneticaily induced transparency （EIT）. Based on a relativistic kinetic model, by expansion of relativistic Lorentz factor in terms of lasers amplitude, we obtain the coupled nonlinear dispersion relations. It is observed that due to resonance in the second harmonic of plasma beat-wave, the new EIT pass-band is created in the high intensities of lasers. The effect of amplitude and frequency variation on the dispersion is numerically investigated.展开更多
文摘A Mach-Zehnder(MZ) electro-optic(EO) modulator are real iz ed,with three optical layers as polymer materials.The functional layer is the co rona poled crosslinkable polyurethane.The ridge waveguide is fabricated by using the spin-coating,poling,photolithography and oxygen reactive ion etching(RIE) techniques.The mode and the modulation properties of these devices are demonstra ted in a micron control system,while the light source works at the wavelength of 1 31 or 1 55 micron.
文摘An electrostatic model for the shock observed in the earth's polar region is established by deriving the 'Sagdeev potential' from the magnetohydrodynamic equations in a cylindrical coordinate system. The results show that the shock can develop from the ion acoustic wave or ion cyclotron wave in the polar region, and can exist when the Mach number M and the initial electric field E-0 satisfy the condition of vertical bar(a/M-2-1)E(0)vertical bar = 1. Also, some features of the shock wave are discussed. The result can interpret the electrostatic shock observed in the earth's polar region.
文摘We study behavior of an atomic wave packet in a circularly polarized electromagnetic wave, and particularly calculate the atomic inversion of the wave packet. A general method of calculation is presented. The results are interesting. For example, if the wave packet is very narrow or/and the interaction is very strong, no matter the atom is initially in its ground state or excited state, the atomic inversion approaches zero as time approaches infinity. If the atom is initially in its ground state and excited state with the probability 1/2 respectively, and if the momentum density is an even function, then the atomic inversion equals zero at any time.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 19847004 and 10474025.
文摘We study theoretically transport properties of two-dimenslonal electron gases through antiparallel magneticelectric barrier structures. Two kinds of magnetic barrier configurations are employed： one is that the strength of the double δ-functlon in opposite directions is equal and the other is that the strength is unequal Similarities and differences of electronic transports are presented. It is found that the transmission and the conductance depend strongly on the shape of the magnetic barrier and the height of the electric harrier. The results indicate that this system does not possess any spin filtering and spin polarization and electron gases can realize perfect resonant tunneling and wave-vector filtering properties. Moreover, the strength of the effect of the inhomogeneous magnetic field on the transport properties is discussed.
基金Supported by Hubei Province Key Laboratory of Systems Science in Metallurgical Process (Wuhan University of Science and Technology) under Grant No.C201018 the National Natural Science Foundation of China under Grant No.10805035
文摘We theoretically investigate the wave-vector and temperature-dependent electron transport in a magneticnanostructure modulated by an applied bias.The large spin-polarization can be achieved in such a device,and the degreeof spin-polarization strongly depends on the transverse wave-vector and the temperature.These interesting propertiesmay be helpful to spin-polarize electrons into semiconductors,and this device may be used as a spin filter.
基金financial support from the Department of Science and Technology of Guangdong Province,China(2019A050510043)Shenzhen Science and Technology Innovation Commission(JCYJ20180507183818040)。
文摘Zinc-air battery is one of the most promising next-generation energy conversion and storage systems.Green and low-cost catalysts with high oxygen reduction reaction(ORR)catalytic activity are desired to meet the requirements of Zinc-air batteries.Herein,poly-active centric Co3O4-CeO2/Co-N-C(ketjenblack carbon)catalysts were prepared by a facile method.The Co3O4 and CeO2 nanoparticles are uniformly anchored on the surface of Co and N doped carbon support.The half-wave potential of Co3O4-CeO2/Co-N-C in the rotating disk electrode testing is close to that of Pt/C.The Zn-air battery using Co3O4-CeO2/Co-N-C as the cathode catalyst can provide a high specific capacity of 728 mA h g^-1 at 20 mA cm^-2 and maintain a stable discharge voltage.The remarkable catalytic performance is mainly attributed to the synergistic effect among Co3O4,CeO2 and Co-N-C,the outstanding electrical conductivity and the large surface area.Benefitting from the high catalytic activity,environmental friendliness and the facile synthesis process,Co3O4-CeO2/Co-N-C catalyst lends itself well to a great prospect in the application of metalair batteries.
文摘In the present paper the problem of nonlinear interaction of two mildly-relativistic circularly polarized lasers in a cold plasma is studied in order to investigate electromagneticaily induced transparency （EIT）. Based on a relativistic kinetic model, by expansion of relativistic Lorentz factor in terms of lasers amplitude, we obtain the coupled nonlinear dispersion relations. It is observed that due to resonance in the second harmonic of plasma beat-wave, the new EIT pass-band is created in the high intensities of lasers. The effect of amplitude and frequency variation on the dispersion is numerically investigated.
