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Infrared Search and Track (IRST) System has become the main approach to cover a wide area with high resolution imagery of long-range targets. A fast-steering mirror (FSM) is generally integrated in the optical system to provide back scanned motion for maintaining the line-of-sight stability. However, the conventional optical designs can hold only the center of field relatively stable on the FPA during back-scanning; all other field points may wander during the exposure time due to imaging distortion characteristic of the optical system which reduces the quality of the observed images. This paper reports a lens design with implemented Non-Rotationally symmetric field mapping which can keep all field points stable on the FPA during back-scanning. This lens design covers a large Field of view (FOV) of 10° x 8° for single frame and a maximum scanning angle of 2.16°. With a F/2 SXGA (1280 x 1024) cooled detector, this optical system help scan a large number of objects in a long-range distance at a high scanning rate with diffraction limit performance.

This paper reports a design process for high magnification mid-wave infrared continuous zoom lens. The process consists of algorithms for finding global paraxial solution, optimization strategies for balancing aberrations in all zoom configurations, and cam curve smoothing methods in opto-mechanical design. Using this process, a parfocal continuous zoom lens with F/4, magnification of 20× working with a 640x512 cooled 15μm pixel pitch detector array, has been successfully designed and fabricated. In principal, this design bases on a zoom and a focus group. The zoom group consisting of three separate moving lens subsets allows for a high magnification ratio of 20× and its parfocality during continuous zooming, while the focus group helps changing focal planes and ensures normal operation in a large temperature and observation range. The lens uses different optical surfaces varying from spherical to hybrid diffractiveaspheric form. This results in high optical performance with MTF approaching diffraction limit while keeping the overall system compact and light weight. For the coordination of lens movement in the zoom group, smooth cam curves having satisfactory stiffness and pressure angles were achieved by a smoothing method which maps different system focal length values with appropriate barrel rotation angles. The simulation of optical performance and experimental testing results will be presented. This zoom lens can be used in long range surveillance camera system.

Degradation of chitosan in swollen state with hydrogen peroxide solution (5% w/v) by γ-irradiation was investigated. Molecular weight (Mw) of irradiated chitosan was determined by gel permeation chromatography (GPC). Fourier transform infrared (FT-IR) and ultraviolet-visible (UV-vis) spectrawere analyzed to study the structure changes of degraded chitosan. The results showed that the chitosan of low Mw ~30-45 kDawas efficiently prepared by γ-irradiation of chitosan swollen in hydrogen peroxide solution at low dose less than 20kGy. The main structure as well as the degree of deacetylation of the degraded chitosan was almost no significant change. Furthermore, the radiation degradation yield (Gs) was remarkably enhanced by the presence of H2O2. The obtained low Mw chitosan revealed high antimicrobial activity for E. colithat can be used for food preservation and other purposes as well.

Degradation of chitosan in swollen state with hydrogen peroxide solution (5% w/v) by γ-irradiation was investigated. Molecular weight (Mw) of irradiated chitosan was determined by gel permeation chromatography (GPC). Fourier transform infrared (FT-IR) and ultraviolet-visible (UVvis) spectrawere analyzed to study the structure changes of degraded chitosan. The results showed that the chitosan of low Mw ~30-45 kDawas efficiently prepared by γ-irradiation of chitosan swollen in hydrogen peroxide solution at low dose less than 20kGy. The main structure as well as the degree of deacetylation of the degraded chitosan was almost no significant change. Furthermore, the radiationdegradation yield (Gs) was remarkably enhanced by the presence of H2O2. The obtained low Mw chitosan revealed high antimicrobial activity for E. colithat can be used for food preservation and other purposes as well.