Guang Pu Xue Yu Guang Pu Fen Xi
April 2015
Linear variable filters (LVF) are widely used in a variety of small rapid spectrometric detecting devices. In the present paper, the splitting property of LVF was studied, and the spectral-property expression in Gaussian form was given, and the relationship between indexes of expression and LVF center transmission, width of spectrum, and linear dispersion was specified. Measurement based on monochromator for imaging spectrometers calibration was introduced, the sensitivity for detection system was discussed, and the tolerance was analyzed.
View Article and Find Full Text PDFGuang Pu Xue Yu Guang Pu Fen Xi
July 2014
The principle and instrumental structure of large aperture static imaging spectrometer (LASIS) were briefly described in the present paper, the principle of the Mach-Zehnder imaging spectrometer was introduced, and the Mach-Zehnder interferometers' working way in the imaging spectrometer was illustrated. The structure of solid Mach-Zehnder interferometer was analyzed, and discussion was made based on the requirements of field of view (FOV) in image space and single sided interferogram with a small portion around zero path difference (ZPD). The additional optical path difference (OPD) created by manufacturing and matching tolerance of two asymmetrical pentagonal prisms will lead to the displacement of shearing and OPD nonlinearity.
View Article and Find Full Text PDFGuang Pu Xue Yu Guang Pu Fen Xi
June 2012
A wide-field pushbroom hyperspectral imager covering short-wavelength infrared range is presented, which can be carried by space borne or airborne platform for remote sensing, acquiring hyperspectral data cube, and analyzing substance compositions and physicochemical properties. Curved prism which simultaneously possesses the functions of dispersion and imaging is used as the prismatic element, and the combination with Offner relay configuration substantially simplifies the design of spectrometer. Compared to conventional dispersive spectral imagers, this design is compact, light-weighted, and small-sized, and can efficiently correct unavoidable spectral line curve (smile) and spectral band (keystone or frown) by prismatic dispersion Compared to grating spectral imagers of the same configuration, the energy utilization efficiency of this design is much higher.
View Article and Find Full Text PDFThe occurrence and phase distribution of polycyclic aromatic hydrocarbons (PAHs) in waters at the eight riverine outlets of the Pearl River Delta (China) were examined based on a monthly sampling program from March 2005 to February 2006. The total concentrations of PAHs in the aqueous phase and suspended particulate matter (SPM) combined ranged from 55.5 to 522 ng/L, at the mid level of the global values in rivers and estuaries.
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