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Yuan X.-J.,Beijing Institute of Environmental Characteristics
Chinese Physics Letters | Year: 2012

In comparison with the phenomenon of negative index refraction observed in artificial meta-materials, it is interesting to ask if this type of behavior also exists or not in reaction-diffusion systems that support nonlinear chemical waves. Previous studies indicate that the negative index refraction could occur on a interface between a medium of a normal wave and a medium that supports anti-waves. Here we investigate the phenomenon in the complex Ginzburg - Landau equation (CGLE) in a close relationship with the quantitative model for the chloriteiodide-malonic acid (CIMA) reaction. The amplitude equation CGLE is deduced from the CIMA reaction, and simulations with mapped parameters from the reaction-diffusion equation reveal that the competition between normal waves and anti-waves on the interface determines whether the negative index refraction occurs or not. © 2012 Chinese Physical Society and IOP Publishing Ltd.


Hu L.,Beijing Institute of Environmental Characteristics | Liu H.,Xidian University | Zhou P.,Beijing Institute of Environmental Characteristics
Lecture Notes in Electrical Engineering | Year: 2010

An image feature extraction method, generalized 2-dimensional clustering-based discriminant analysis (G2DCDA), is proposed. This method can compress images along both rows and columns, and thus overcoming the drawbacks of too large feature matrices of 2DCDA. In addition, similar to 2DCDA, G2DCDA not only has the computational advantages of the 2D subspace methods available, but can deal with the multimodal distribution problems. Experiments conducted on the moving and stationary target acquisition and recognition (MSTAR) public database demonstrate that G2DCDA is more efficient than some 2D existing subspace methods, such as 2D principal component analysis (2DPCA), 2D linear discriminant analysis (2DLDA) and 2DCDA. Moreover, G2DCDA achieves higher recognition rates and lesser memory requirements. © 2010 Springer-Verlag Berlin Heidelberg.


Wang M.,Xian Yang Normal College | Li Y.L.,Xian Yang Normal College | Wang Y.,Beijing Institute of Environmental Characteristics | Xiang N.,Xian Yang Normal College | Xiang N.,Xidian University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

It has used the two-frequency mutual coherent function to study pulse scattering from one dimensional perfectly conducting rough surface. So this paper is mainly focused on that the analytical expressions for incoherent mutual function (MCF) for pulse scattering from one-dimensional random rough surface are obtained based on the Kirchhoff's approximation. According to the analytical solutions, numerical methods are shown that coherent and incoherent mutual function (MCF) change with the coherence bandwidth frequency difference and scattering angles in different incident angles incidence on laser (1.06μm) according to the mean of fluctuating heights and correlation length of the rough surfaces. And some important scattering characteristics of the coherent and incoherent mutual function (MCF) are be obtained in details. Our works is helpful when investigating the statistical characteristics of laser scattering fields of objects with rough surface. © 2013 SPIE.


Wang H.P.,Beijing Institute of Environmental Characteristics | Ji D.,Beijing Institute of Environmental Characteristics | Chen D.,Beijing Institute of Environmental Characteristics
Applied Mechanics and Materials | Year: 2013

A high-performance vehicle multi-axis optical encoder data acquisition system based on PC104 bus is introduced. The paper puts emphases on the main function of the system module. VHDL hardware description language is used to design the modules, and ModelSim is introduced to implement logic and sequential simulation. An experiment is carried on in Altera EPF10K40 chip. Both the simulation and experimental results verify the correctness and validity of the method. © (2013) Trans Tech Publications, Switzerland.


Liu J.,Science and Technology on Optical Radiation Laboratory | Deng R.,Science and Technology on Optical Radiation Laboratory | Wei A.,Beijing Institute of Environmental Characteristics | Yu Z.,Beijing Institute of Environmental Characteristics
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2014

For the miniaturization and portability demands of solar simulator, a portable solar simulator was designed. Illumination in 1.2 m×1.2 m rectangular irradiated area not less than 0.02 solar constant was required; furthermore, the un-uniformity of irradiated surface less than 5% was also needed. The system mainly consisted of short-arc xenon lamp, ellipsoidal reflector, fiber optic beams, and a group of collimating lens. Through software simulation and experimental verification, the results met all the requirements. Experimental results show that the method that designing a portable solar simulator with short-arc xenon lamp, ellipsoidal reflector, fiber optic beams, integral stick, and projection collimator lens group is effective and feasible. ©, 2014, Chinese Society of Astronautics. All right reserved.


Zhang H.,Science and Technology on Optical Radiation Laboratory | Ma Y.,Science and Technology on Optical Radiation Laboratory | Ji D.,Beijing Institute of Environmental Characteristics | Chen D.,Beijing Institute of Environmental Characteristics | Wang H.,Beijing Institute of Environmental Characteristics
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2016

As the large optoelectronic tracking device has the features of high tracking and measuring precision, large inertia and small field, it has no ability to search targets in large sky scope. Generally, it depends on the leading information from radars to find targets. Once the information's error exceeds the field of the device, it's hard for the optoelectronic tracking device to find the target. A quick helical search method in small sky scope was proposed based on the leading information. According to system model simulation and experiments, the method helped the large optoelectronic tracking device to capture target quickly when the target's leading information error outranged the field. The acquisition probability of targets was increased from 20% to 70% when the leading information error was less than twice of the device field. The turntable runned smoothly when applying this search method, and the searching parameters can be changed flexibly according to properties of different optoelectronic devices, features of targets and targets guiding error. It greatly improves acquisition probability of targets, and it is a kind practical and effective method for large optoelectronic device to find targets quickly in small sky scope. This method has high versatility. © 2016, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.


Hu L.P.,Beijing Institute of Environmental Characteristics
Proceedings of 2011 IEEE CIE International Conference on Radar, RADAR 2011 | Year: 2011

An image feature extraction technique, two-directional two-dimensional k-nearest neighbour discriminant analysis ((2D) 2k-NNDA), is presented from the viewpoint of the k-nearest neighbour (k-NN) classification, which is an extension of 2DNNDA based the idea of the nearest neighbour (1-NN) classification. Similar to 2DNNDA, (2D) 2k-NNDA makes use of the matrix representation of images and does not assume the class densities belong to any particular parametric family. (2D) 2k-NNDA is applied to target recognition and the results demonstrate that (2D) 2k-NNDA achieves at least the same or even higher recognition accuracy than the existing 2D subspace methods. © 2011 IEEE.


Liu J.,Beijing Institute of Environmental Characteristics | Liu J.,Science and Technology on Optical Radiation Laboratory | Deng R.,Beijing Institute of Environmental Characteristics | Deng R.,Science and Technology on Optical Radiation Laboratory | And 3 more authors.
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2015

According to the demands of target characteristics research, a solar simulator with 2.4 m-diameter effective illuminated area was designed. Several targets were required that the illumination of irradiated area was not less than 0.3 solar constant; the collimating angle of outgoing beam was less than ±1°, the un-uniformity of irradiated surface was less than ±3% and the spectral mismatch error reached level C. The solar simulator consisted of four short-arc xenon lamps, four ellipsoidal reflectors, two flat reflectors, a group of optical integrator, and a collimating reflector. Software simulation analysis and experiment test were carried out for the design. Test results show that the diameter of effective illuminated area is 2.43 m, the mean illumination of irradiated area is 3382 lx, the collimating angle of outgoing beam is ±0.97°, the un-uniformity of irradiated surface is ±2.8% and the spectral mismatch error reaches level C, which meet all the requirements. © 2015, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.

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