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Biomedical subjects

Guang-yin Zhang

Publications and source records attributed to Guang-yin Zhang.

3 recordsLinked to original sources

[Research of image spectrometer using linear variable interference filter].

In the present work we have designed a small-size portable imaging spectrometer using linear variable interference filter, with CCD camera as picture sensor, and micromotion stage to bring along interference filter which scan across every pixel of CCD array. The difference column pixel in the picture which we get at every step is monocolour partial image under different wavelength, with the step by step, these column monocolour pixels change the wavelength. And finally we reassembled these images and get the whole monocolour image with different wavelength. The interval of sweep step length decided by the required spectrum resolution and the required wavelength interval of different pictures. The experiment demonstrated the resolution of this spectrometer is about 16 nm, but that major reason of the limiting resolution is the band width of the linear variable interference filter. The spatial resolution of the instrument ultimately decided by CCD, filter and imaging lens. This spectrometer has some characters such as compact structure, higher spatial resolution, higher spectrum resolution, higher scan rate and so on. Furthermore, an application of this instrument in distinguishing from camouflage have been showed.

Analog-Digital Conversion↗

[Calculation of spectroscopic properties of Tm:YVO4 crystals].

Sigma and pi polarized absorption spectra of Tm:YVO4 crystal have been measured at room temperature. Considering the difference of the sigma and pi polarized absorption spectra and the changing of the refractive index with different wavelengths, we calculate the intensity parameters of Tm3+ in crystal YVO4 which are omega 2 = 1.9416 x 10(-20) (cm2), omega 4 = 0.1568 x 10(-20) (cm2), omega 6 = 0.3963 x 10(-20) (cm2) by Judd-Ofelt theory. The spectra characteristic parameters, such as radiative transition rates, luminescence branching ratio, total radiative lifetime and integral cross-section are also calculated. The results show that the spontaneous rate of the transition 1D2-->3F4 is much higher than that of the transition 1D2 to other levels.

Chemical Phenomena↗