摘要：Cascading stages of high gain harmonic generation free electron laser （FEL） seem to be a feasible way to generate short wavelength radiation. With help of the analytical estimates, we design a two-stage cascading scheme to achieve 131 nm DUV radiation on the basis of the Shanghai deep ultraviolet free electron laser test facility. Detailed studies on the FEL performance, the stability and the sensitivity of the output power to parameter variation have been achieved by GENESIS1.3, and design of the lattice structure is presented.

摘要：Based on the femtosecond accelerator device, we are planning to build a broad band and tunable THz source using the Smith-Purcell radiation mechanism. Coherent Smith-Purcell radiation could be achieved owing to the super-short bunch produced in the device. To shorten the distance between the beam and grating, we use Transport to match the beta function producing a sheet beam on the grating surface. The optimization of grating length, groove depth and groove width are given in the paper. Then the radiation power for the shallow and deep grating using these parameters are presented. The detection devices and methods are also briefly discussed.

摘要：Nonuniform flow distribution along the radial direction usually exists in a Z-flow type radial flow adsorber,which will decrease the utilization of adsorbent and the switching time and may result in operating safety problems in cryogenic air *** order to improve the uniformity of the flow distribution along the radial direction in the adsorber,a differential equation is derived through pressure drop analysis in the Z-flow type radial adsorber with a cone in the middle of the central *** differential equation determines the ideal cross-sectional radii of the cone along the *** result shows that the cross-sectional radius of the cone should gradually decrease from 0.3 m to zero along the axis to ensure that the process air is distributed uniformly in the Z-flow type radial flow adsorber and the shape of the cone is a little *** flow distribution without the cone in the central pipe is compared under different bed *** is demonstrated that the proposed differential equation can provide theoretical support for designing Z-flow type radial flow adsorbers.

摘要：A new equivalent circuit model of organic-light-emitting-diode （OLED） is proposed. As the single- diode model is able to approximate OLED behavior as well as the multiple-diode model, the new model will be built based on it. In order to make sure that the experimental and simulated data are in good agreement, the constant resistor is exchanged for an exponential resistor in the new model. Compared with the measured data and the results of the other two OLED SPICE models, the simulated I-V characteristics of the new model match the measured data much better. This new model can be directly incorporated into an SPICE circuit simulator and presents good accuracy over the whole operating voltage.

摘要：We present a design study of a free electron laser （FEL） oscillator for high power THz source experiments on the basis of the Shanghai femtosecond accelerator device. A circular groove guide is used as a new interaction structure. Plane metal meshes are used as upstream and downstream mirrors of the resonator. The general design parameters are presented. We analyzed the spontaneous emission and stimulated emission in the oscillator using these parameters.

摘要：We adopt the groove guide as the cavity of the undulator to reduce the diffraction effect. The groove guide has the advantages of lower surface energy loss, larger power capacity, less modes, and larger structure dimension over the traditional method waveguide. The attenuation calculation is given in this paper including the cavity optimization. And the dispersive character indicates that the oscillator can work in different modes with the change of the electron beam energy.

摘要：A surface plasmon resonance(SPR) sensor based on a multi-core photonic crystal fiber(PCF) is presented in this *** is only one analyte channel positioned in the center of the PCF cross section,rather than several closely arranged analyte channels around the central *** the design of this sensor not only reduces the consumption of gold and samples,but also effectively avoids the interference between neighboring analyte *** field distributions of this fiber at different wavelengths and the sensing properties of this sensor are theoretically analyzed and discussed using finite element method(FEM).Simulation results confirm that both the thickness of metallic layer and the fiber structural parameters have significant effect on sensing *** amplitude sensitivity of the sensor is found to be 1.74×10-5RIU,and the spectral sensitivity is 3300 nm/RIU,corresponding to a resolution of 3.03×10-5 ***,in order to achieve PCF-SPR sensing characteristics,an experiment design scheme based on spectroscopic detection method is proposed.

摘要：In this paper, a novel photonic crystal fiber （PCF） with high birefringence and nonlinearity is designed. The charac- teristics of birefringence, dispersion and nonlinearity are studied by using the full-vector finite element method （FVFEM）. The numerical results show that the phase birefringence and nonlinear coefficient of PCF can be up to 4.51× 10-3 and 32.8972 ***-1 at 1.55 μm, respectively. The proposed PCF could be found to have important applications in the polarization-dependent nonlinear optics such as the pulse compress and reshaping in the C waveband.

摘要：In order to meet the requirements of the synchrotron radiation users, a fully coherent VUV free electron laser （FEL） has been preliminarily designed. One important goal of this design is that the radiation wavelength can be easily tuned in a broad range （70 170 nm）. In the light of the users＇ demand and our actual conditions, the self-seeding scheme is adopted for this proposal. Firstly, we attempted to fix the electron energy and only changed the undulator gap to vary the radiation wavelength; however, our analysis implies that this is difficult because of the great difference of the power gain length and FEL efficiency at different wavelengths. Therefore, we have considered dividing the wavelength range into three subareas. In each subarea, a constant electron energy is used and the wavelength tuning is realized only by adjusting the undulator gap. The simulation results show that this scheme has an acceptable performance.

摘要：A complete algorithm to design 4-band orthogonal wavelets with beautiful structure from 2-band orthogonal wavelets is presented. For more smoothness, the conception of transfer vanishing moment is introduced by transplanting the requirements of vanishing moment from the 4-band wavelets to the 2-band ones. Consequently, the design of 4-band orthogonal wavelets with P vanishing moments and beautiful structure from 2-band ones with P transfer vanishing moments is completed.