Search

The research and achievements of high performance polarizer coatings by many scholars around the world are reviewed, including the spectral properties, laser damage threshold and stress control. For the performance requirements of polarizer coatings in China Shenguang series facilities, it describes the investigation of spectral properties, laser damage threshold, and figure accuracy of the polarizer coatings based on electron beam depolarization by Shanghai Institute of Opitcs and Fine Mechanics of the Chinese Academy of Sciences(SIOM). Much work and achievements on design, preparation and past-treatment of the coating are given. On the basis of the research achievements, high performance thin films polarizer with low defect density and low stress have obtained. The Brewster angle thin film polarizer developed by our team has participated in the International Laser Damage Competition held on the SPIE 2012 Laser Damage & SPIE 2013 Laser Damage Symposium. The p-polarized LIDT(Laser Induced Damage Threshold) as well as the average of p-polarized and s-polarized LIDT achieves the best results. The stress-induced crazing of large aperture polarizer coating is also solved, by which the manufacturing of large aperture polarizer is implemented in China, showing the spectral properties of TP>98%, RS>99% and the flux property of 17 J/cm2(9 ns). Now, the prepared large aperture polarizer has supported the stable operation of ShenguangII-UP laser facility. ? 2016, Science Press. All right reserved.

Pelage is one of the most important characteristics of mammals.The research about the association between molting and environment is an important aspect in the study of animal ecology.Mammals′ autumn molting is completely to taking off their summer hairs and growing rich hairs in winter.But the quantitative studies of thermal insulation of animals′ pelage which was changing in the autumn molting process have not been involved.Our objective was to find out the relationship between characteristics and heat insulation of hair in squirrel,Sciurus vulgaris manchuricus,that is molting in autumn.In order to study the association between hair length and pelage thermal insulation property,we measured hair length and tested thermal insulation of skins of 27 female squirrels(Sciurus vulgaris manchuricus)(twenty-five adults and two subadults) during autumn molting period.The hairs(5 intermediate guard hairs and 5 undercoat hairs) were sampled from the mid back of each skin and thermal insulation was tested at the same site.Results showed that 1) with the progression of autumn molting,the pelage thermal conductivity decreased in association with increment of winter hair length,and reached stable at the end of hair growth.2) Significant positive associations were detected between pairs of four hair indexes namely the length of intermediate guard hairs,length of under hairs,root of medulla-absent proportion in intermediate guard hairs and under hairs(P0.01).Meanwhile,these four indexes were also significantly negatively associated with thermal conductivity coefficient(P0.01).These results suggest pelage thermal conductivity is effected by the thickness of under fur.In conclusion,the results reflect the specific changes and interrelation of hair length,the extent of growth and thermal insulation in the every time stage during autumn molting period.

To support the correct design of cryogenic optical systems,a measuring system for the detectivity of infrared detectors in low temperature background was established and applied to some infrared detectors for testing their detection characteristics.First,the theoretical analysis for noise and response characteristics of an infrared acquisition system was introduced,and the relationship between the design of a low temperature optical system and the detectivity of infrared detector in the low temperature background was established.Then,a measurement system of detectivity in the low temperature background based on thermal vacuum enviroment was proposed,and experimental research on some infrared detectors in the low temperature background was accomplished.Finally,the variation regularities of limiting integration time and detectivity in low temperature compared with those in normal temperature case were discussed as well.Experimental results indicate that both of the integration time and detecitivity in the low temperature background are 20times that in normal temperature background.The regularity derived can satisfy the requirments of system index design of low temperature optical systems.

In consideration of the development trends of backlights,a global dimming algorithm for side-lit backlights was proposed to solve the problems of Liquid Crystal Devices(LCDs) in low contrast ratio and high power consumption.The backlight dimming level was decided by the average luminance and the difference between the average and max grayscales of all subpixels.Then,the S-shaped function was involved to improve the static contrast ratio,by which the pixels with the grayscales more than the turning point of the curve could be become brighter and those less than the turning point could become darker,so that the static contrast ratio was improved efficiently.The algorithm was simulated and a prototype was developed to evaluate the effects of the dimming algorithm.Experimental results indicate that the power consumption of the LCD with the global dimming heavily depends on what to be displayed on the images.For 40 different kinds of images,the average power has reduced by 9.39% and the static contrast ratio improved by 124.7%.The side-lit backlights performing the proposed global dimming algorithm have the advantages of low-cost,small thickness,low power consumption and high constrast ratio.

To reveal the error propagation rules of camera geometric specification in stereoscopic mapping more accurately,the relationship between the mapping accuracy and specification difference parameters of dual-linear-array CCD camera is studied.Aiming at the characteristic of dual-linear-array stereoscopic mapping,effects of the geometric specification difference parameters on mapping positioning are analyzed.Based on the space forward intersection formula,the positioning accuracy(PA) model is established,and then the variations of PA with the difference between calibration errors of interior orientation elements are presented.The results show that the effect of the difference between principal point x errors on PA is obvious,and the PA rapidly decreases by 60% when the difference change increases to 2.5 μm from 1 μm.In addition,the effect of the difference between focus length f errors on PA can be almost neglected.The model and relevant conclusions have important guiding meaning for the optimization design and quantification of dual-linear-array CCD camera specification.

A on-line monitoring system was developed for the determination of chemical oxygen demand in water based on full-spectrum analysis.In this system,least-square method was used to obtain the transmission equation between absorbance and chemical oxygen demand(COD)value by measuring absorption spectra of water with known COD value,and then the established equation could inverse the COD values of the unknown water samples.For the COD determination of simulated complicated water samples,the instrumental reliability was well validated by comparing the measurement values of the analyzer with that of laboratory results.The monitoring system provided advantages of simplicity,rapidity,high precision,low consumption and environmental benignity,and was demonstrated an ideal alternative to real-time and on-line monitoring of COD in water.

To achieve sustainable development of wildlife resources,the protection of wildlife and maintenance of ecological balance has become one of the key goals in China.For the protection of wildlife resources,it is necessary to quantitatively study the trend in sustainable development of these wildlife resources.Analysis of the general trend of sustainable development,which is achieved by sustainable development wildlife resources,the protection of wildlife resources and habitat,and ecological balance,has important theoretical meaning as well as practical significance. In this paper,we established a system of wildlife sustainable evaluation indicators.We also used the entropy method to determine the weight of each index,examined the protection of wildlife resources and development of harmonious resource use,and analyzed the overall tendency of sustainable development of wildlife resources.The results show that:(1) From 2001—2009 in China there was an upward trend in the wildlife and habitat protection index,resource economic comprehensive index,and social progress index.(2) The degree of coordination between wildlife and environmental protection and comprehensive resource economics was 0.14—0.35 in 2001—2005 and 2007—2009.Also,the overall coordination development was at a relatively low level,which belonged to the class of disorders of recession.The degree value was 0.45 in 2006,which belonged to the coordination development in the transition phase.(3) Although the wildlife resource sustainable development level was increasing,the overall level was low.The comprehensive index was between 0.15—0.31 from 2001—2005,and between 0.45—0.47 from 2007—2008,which belonged to the traditional backward stage of development.The integrated index was 0.55 in 2006 and 0.56 in 2009,which was achieved by the transition from traditional development to sustainable development. Based on the actual situation of China′s wildlife protection,combining the related data analysis affects sustainable development of wildlife resources for the following reasons:(1) negative effects on wildlife and habitat protection;(2) need for more comprehensive wildlife advocacy;(3) the overall level of wildlife breeding industry needs to advance;(4) the wildlife resource industry level needs to be further improved;(5) wildlife resources for the sustainable development of macroeconomics must be regulated and controlled.On this basis we propose the following four methods to promote the sustainable development of wildlife resources in China:(1) Further strengthen the protection of wildlife and habitats.This can be done by developing teams of professional staff to work in wildlife protection,improving staff welfare,establishing community co-management systems,and galvanizing the enthusiasm of residents for the protection of wildlife.(2) Conduct public campaigns for "the science behind wildlife conservation".Develop new strategies for wildlife protection and new methods of publicity aimed at educating the public on the importance of reducing their use of wildlife resources.(3) Increasing scientific research on wildlife breeding to overcome current technical barriers.Optimization of industrial structure of wildlife resources to improve the quality of wildlife as a product.(4) Further improve laws and regulations governing wildlife resources,and promote development of a legal system to oversee the resource utilization industry.

In consideration of the effect of radiometric specification of a mapping camera on the matching accuracy of imaging,the quantification of main radiometric specifications are analyzed,and the mathematical model between them is developed to provide theoretical foundations for determining the specifications of the mapping camera.Firstly,Least Squares Image Matching Algorithm(LSIM) is deduced mathematically,and then the main factors impacting matching accuracy are presented,including the scene characteristics,Modulation Transfer Function(MTF) for an imaging system,Signal to Noise Ratio(SNR) and Radiometric Distortion(RD) metrics.Then,the image degradation owing to the above factors is modeled and simulated.Based on LSIM,the mathematical model between matching accuracy and radiometric specifications is developed using Genetic Algorithm and Back-propagation Neural Network(GABPNN).Finally,the model is verified using simulated images and on-orbit images.Experimental results indicate that the model precision is less than 0.01pixels.It suggests that when the MTF N is set to be greater than 0.08,SNR greater than 45and RD less than 4% based on the model,the error of matching accuracy can be less than 0.1pixel.

Based on the physical model of which the targets were irradiated through artificial illuminator in normal circumstance,the calculation model of surface temperature was built through building heat conduction differential equations and altering the outedge radiation power.Combing the calculation of surface temperature related to targets′s geographical circumstance and orientation,taking the Hefei building′s eastward surface for example,the surface temperature was simulational calculated and discussed in different irradiation times and illumination parameters.The results show that altering the targets′s outedge namely the targets are irradiated through artificial illuminatorm,the temperature of targets are changed,the degree of variety is determined by illuminator′s power,distance,incident angle,and in general conditions,the surface temperature is changed obviously in the night,but not in the daytime.

In order to realize the automatic image registration for infrared images and visible images,an image registration method based on the Expectation Maximum(EM) iteration of the log-likelihood function is proposed.This method utilizes the image edge as the registration point,and thus the image registration is transferred into an edge point set registration.The point set is modeled as Gauss Mixture Model(GMM),and the likelihood function of the point set registration is obtained.To solve the affine transform parameter,the likelihood function is maximized with EM iterations.And during the EM iterations,the probability density of edge point is segmented with an adaptive threshold to eliminate the outer points,and the interference of outer point with the likelihood function is overcome and the affine transform parameter is determined accurately.The experiments on image registration for infrared images and visible images are verified,and the results indicate that the proposed method is effective.

Implementation of pulsed-pump technique to fiber amplifier is significantly useful in the situation of low repetition rate and high energy pulses operating.The Amplified Spontaneous Emision(ASE) dynamics simulation in a pulsed-pumped ytterbium-doped double-clad fiber amplifier was presented,which provides important references about optimizing the pulsed-pump mode.By solving the rate equations and light power propagation equations in fiber using the finite elements analysis method,the simulations of ASE dynamics were carried out,including evolution of forward,backward ASE power distribution in the fiber and variations of ASE output power at two ends of the fiber in the time span from 0~740 μs after injection of pump light.Through the analysis of simulation results,the difference between forward and backward ASE powers increasing speeds and characteristics of the two kinds of ASE powers distributions dynamic in fiber were indicated.