Papers by Author: Qiang Xu

Abstract: We propose a novel type of photonic crystal fiber with low fattened dispersion and high nonlinearity for four wave mixing. The dispersion and nonlinearity coefficient are investigated simultaneously by using the full vectorial finite element method with anisotropic perfectly matched layers. The optimized result has been obtained by adjusting the design parameter of the proposed fiber, which has dispersion is -1.53 ps•nm−1 km−1 at wavelength of 1.55μm, and in addition the relatively small effective mode area of 2.23μm2 is obtained at the same wavelength, which will induce higher nonlinearity coefficient is close 54.8 W-1• km-1 at the wavelength of 1.55μm. The proposed PCF is suitable for applications as a chromatic dispersion controller, dispersion compensator, or as candidate for the nonlinear optical systems because of its small effective mode area.

Abstract: After the horseradish peroxidase (HRP) was treated with different dose of N+ ion beam, the effect of N+ ion beam on the secondary structure of HRP was studied by FTIR(Fourier-transformation infrared spectroscopy). The results have shown that different dose ranging from 1015 to 1016 ions/cm2 has different effects on the secondary structure contents the HRP. The N+ implantation induce the mutual change in the secondary structure unit of HRP. It was suggested that N+ ion beam was bound to result in conformational change.

Abstract: The time effects of different vacuum treatment on the activity index (RZ=A403/A280) of the horseradish peroxidase (HRP) was investigated experimentally via the ultraviolet-visible spectroscopic techniques. The results have shown that Ultraviolet-Visible (UV-Vis) spectra have been changed obviously. Experimental results indicate that the conformation of HRP can be changed by vacuum. The activity index decrease possibly was caused by the conformation variations of HRP.

Abstract: The polarization properties of a new structure of high birefringence polarization maintaining photonic crystal fibers were explored, which were consisted of elliptical-holes and near elliptical core triangle lattice of hexangular structure based on polymer. The optical birefringence and the first order polarization mode dispersion were studied based on a full-vector localized basis function method. The numerical results show that the polarization properties are strongly dependent on structural parameters of the PCF. Furthermore, the proposed fiber was fabricated based on MMA monomer polymerization method in situ. So the proposed PCFs may be useful in the field of high birefringence polarization-maintaining optical communication.

Abstract: After the SOD was treated with different strength of electric field, the interactional mechanism of electric field on SOD activity was studied by circular dichroism. The activity of SOD was enhanced under the treatment by different strength of electric field. Circular dichroism spectra showed that the secondary structure of SOD was greatly changed by electric field, as β-sheet and β-turn contents decreased, while α-helix and random coil contents increased. It was considered that the increase of the α-helix structure near the active center would lead to the inactivation of SOD. The result of this study has important meaning to explain the biological effect of electric treatment seeds.

Abstract: The activity of Horseradish Peroxidase (HRP) was enhanced with different strength of high voltage electric field. The results have shown that Ultraviolet-Visible spectra have been changed obviously. Experimental results indicate that the conformation of HRP can be changed by electric field. The study also showed that the activity index of HRP was increased by the certain strength of electric field. The activity index increase possibly was caused by the conformation variations of HRP. The result of this study has important meaning to explain the macroscopical electrostatic biological effects.