中国科学院机构知识库网格系统: 检索

Assessing agricultural non-point source pollution loads in typical basins of upper Yellow River by incorporating critical impacting factors 期刊论文 OAI收割
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION, 2023, 卷号: 177, 页码: 17-28
作者: Zhou, Jinhan; Liu, Xiaohuang; Liu, Xiaojie; Wang, Weili; Wang, Lingqing

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Pollution load Non -point source pollution Rainfall Topographic driving Interception Calculate

Structural amelioration of 920 nm optically pumped semiconductor vertical external-cavity surface emitting laser (OPS-VECSEL) (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Energy, Environment and Sustainable Development, EESD 2012, October 12, 2012 - October 14, 2012, Jilin, China
作者: Liu Y.; Liu Y.; Wang L.; Wang L.; Wang L.

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920 nm optically pumped semiconductor vertical external-cavity surface emitting laser (OPS-VECSEL) has an important application in laser display. We constructed and optimized a 920 nm OPS-VECSEL with active region of In0.09Ga0.91As quantum well (QW) system pumped by 808 nm laser diode module. By the finite element method self-consistent solutions of the semiconductor electronic and optical equations are realized to calculate the characteristics parameters of OPS-VECSEL. The performances of device especially the mode the threshold and the optical-optical translation efficiency were analyzed by dealing with different number of QWs (1 2 and 3) in one period QW depth barrier width the component and dimension of the non-absorption layer. We chose an improved structure of them. On this basis we ameliorated the number of QW periods and the simulation showed that in order to obtain high performance device the choice of the number of QW periods must be cautious. (2013) Trans Tech Publications Switzerland.

A line mapping based automatic registration algorithm of infrared and visible images 会议论文 OAI收割
5th International Symposium on Photoelectronic Detection and Imaging (ISPDI) - Infrared Imaging and Applications, Beijing, June 25-27, 2013
作者: Ai R(艾锐); Shi ZL(史泽林); Xu DJ(徐德江); Zhang CS(张程硕)

收藏 | 浏览/下载：36/0 | 提交时间：2013/12/26

There exist complex gray mapping relationships among infrared and visible images because of the different imaging mechanisms. The difficulty of infrared and visible image registration is to find a reasonable similarity definition. In this paper, we develop a novel image similarity called implicit linesegment similarity(ILS) and a registration algorithm of infrared and visible images based on ILS. Essentially, the algorithm achieves image registration by aligning the corresponding line segment features in two images. First, we extract line segment features and record their coordinate positions in one of the images, and map these line segments into the second image based on the geometric transformation model. Then we iteratively maximize the degree of similarity between the line segment features and correspondence regions in the second image to obtain the model parameters. The advantage of doing this is no need directly measuring the gray similarity between the two images. We adopt a multi-resolution analysis method to calculate the model parameters from coarse to fine on Gaussian scale space. The geometric transformation parameters are finally obtained by the improved Powell algorithm. Comparative experiments demonstrate that the proposed algorithm can effectively achieve the automatic registration for infrared and visible images, and under considerable accuracy it makes a more significant improvement on computational efficiency and anti-noise ability than previously proposed algorithms.

The application of digital signal processing (DSP) for the real time solving of artillery fire control exterior trajectory (EI CONFERENCE) 会议论文 OAI收割
2012 IEEE 3rd International Conference on Software Engineering and Service Science, ICSESS 2012, June 22, 2012 - June 24, 2012, Beijing, China
作者: Li D.

收藏 | 浏览/下载：141/0 | 提交时间：2013/03/25

Method of gain firing data by calculate the group of differential equation has the advantages of high repeatability and high accuracy But much of the CPU time is occupied by the task of re-iteration in computational processing. Therefore it is not the real time processing. This paper introduces a method to quickly determine angle of firing by iteration method which realizes Runge-Kutta method for the equations of exterior ballistic according to the model of mass center motion of projectile. Moreover it also provides the flow of real-time integral solution and be proved by the simulation of MATLAB. Its accuracy satisfies the requirements. This work can be as reference for the design of opt-electrical fire control system and the demonstration work. 2012 IEEE.

The application of Kalman filtering technique on the multi-position strap-down north seeking system (EI CONFERENCE) 会议论文 OAI收割
2012 5th International Symposium on Computational Intelligence and Design, ISCID 2012, October 28, 2012 - October 29, 2012, Hangzhou, China
作者: Liu S.-J.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

In order to fit the sin wave curve of a multiposition strap-down north seeking system and to calculate the real north angle accurately the data collected from the Dynamically tuned gyro(DTG) must be filtered firstly to reduce the noise jamming. The principles of the system are introduced. The factors influencing the measuring precision are also analyzed. Then The DTG data are processed by second-order Butterworth filtering and Kalman filtering together. Experimental results indicate that the built-up filtering method can reduce noise jamming more effectively than second-order Butterworth filtering in the low frequency. 2012 IEEE.

A brightness and color correction method of LED display based on CCD camera (EI CONFERENCE) 会议论文 OAI收割
2012 International Applied Mechanics, MechatronicsAutomation and System Simulation Meeting, AMMASS 2012, June 24, 2012 - June 26, 2012, Hangzhou, China
作者: Wang R.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

The correction methods of LED displays are aiming to address the uniform issues which includes brightness aspect and color aspect. The correction method use a 33 correction coefficients matrix to reshape the pulse width of each LED. To calculate the correction coefficients a linear system is established which includes a color CCD and a LED display. And a correction algorithm is introduced based on the color CCD. This algorithm describes the relationships of the main color components of a LED when the gray level of a LED is increasing or decreasing the three main color components would change according to the correction coefficients. The results shows that the correction based on this algorithm improved the performance of LED displays. (2012) Trans Tech Publications Switzerland.

Design and optimization of supporting structure for scanning mirror in aviation remote sensor (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Electric Information and Control Engineering, ICEICE 2011, April 15, 2011 - April 17, 2011, Wuhan, China
作者: Yang H.

收藏 | 浏览/下载：30/0 | 提交时间：2013/03/25

An optical supporting structure is studied to improve its structure stiffness and reduce the rotate error to meet the requirement of aviation remote sensor. A formula to calculate fundamental frequency is proposed using Rayleigh-Ritz method and a method of is analyzed. By means of OPTISTRUCT software the maximum fundamental frequency is converted to object function the deformation under the gravity and the mass are assigned to state variable wall thicknesses of the structure are converted to design variables. The analysis and test results indicate that the fundamental frequency of designed optical supporting structure has been improved 37.2 Hz from 96.9 Hz which guarantee the reliability of the sweep mechanism and the rotate error is 4.89 which is satisfied for the rotate accuracy in plunge angle. The method of optimization has a certain instructional significance for the design of supporting structures in aviation remote sensor. 2011 IEEE.

Laser pulse coded signal frequency measuring device based on DSP and CPLD (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Laser Sensing and Imaging; and Biological and Medical Applications of Photonics Sensing and Imaging, May 24, 2011 - May 26, 2011, Beijing, China
作者: Zhang H.-B.; Wang T.-F.; Guo R.-H.; Li Y.; Li Y.

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Laser pulse code is an anti-jamming measures used in semi-active laser guided weapons. On account of the laser-guided signals adopting pulse coding mode and the weak signal processing it need complex calculations in the frequency measurement process according to the laser pulse code signal time correlation to meet the request in optoelectronic countermeasures in semi-active laser guided weapons. To ensure accurately completing frequency measurement in a short time it needed to carry out self-related process with the pulse arrival time series composed of pulse arrival time calculate the signal repetition period and then identify the letter type to achieve signal decoding from determining the time value number and rank number in a signal cycle by Using CPLD and DSP for signal processing chip designing a laser-guided signal frequency measurement in the pulse frequency measurement device improving the signal processing capability through the appropriate software algorithms. In this article we introduced the principle of frequency measurement of the device described the hardware components of the device the system works and software analyzed the impact of some system factors on the accuracy of the measurement. The experimental results indicated that this system improve the accuracy of the measurement under the premise of volume real-time anti-interference low power of the laser pulse frequency measuring device. The practicality of the design reliability has been demonstrated from the experimental point of view.

Evaluation of the operating range for ground-based infrared imaging tracking system (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Infrared Imaging and Applications, May 24, 2011 - May 24, 2011, Beijing, China
作者: Zhang Z.-D.

收藏 | 浏览/下载：48/0 | 提交时间：2013/03/25

Ground-based infrared imaging tracking system (GIITS) is of great importance for aerial target warning and guard. The operating range is one of the key performance specifications on the other which should be calculated calculate the radiation power received on the detector in order to analysis whether the output signal meets the detection requirements or not analyzed and studied during the whole GIITS design process. The operating range is mostly influenced by a few factors without considering the effect of the background radiation. By improving of the traditional method including atmospheric attenuation a new operating range calculation model of the GIITS was established based on two requirements. One is that the image size of observed target should meet the requirement of the processor signal extraction. The number of the pixel occupied by target image should be more than 9. The other is that the signal noise ratio (SNR) of the GIITS should not be less than 5 to meet the requirements of the target detection probability and spatial frequency. The SNR calculation equation in form of energy is deduced and the radiation characteristic of the observed target and background are analyzed. When evaluate the operating range of the GIITS using the new method the performance of GIITS and feature of target and background. This paper firstly makes analysis and summarization on the definite localizations of the traditional operating range equation of the GIITS. The localizations are mainly in two aspects. On one hand we should successively calculate two operating range values according to two requirements mentioned above and choose the minimum value as the analytic result. In the end the dispersion of the image and the effect of image dispersion are not considered in the traditional method an evaluation of operating range for fighter aircraft is accomplished as an example. The influence factors in every aspect on operating range were explored by the calculated result. The new operating range calculation model provides the theoretical basis for the design and applications as well as the comprehensive evaluation of a GIITS. 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Data processing method of multi-position strap-down north seeking system based on SVD (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Mechatronic Science, Electric Engineering and Computer, MEC 2011, August 19, 2011 - August 22, 2011, Jilin, China
Shen C.-W.; Liu C.; Yu S.-B.; Wang Z.-Q.; Li J.-R.

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With the aim to fit the sin wave curve of a multi-position strap-down north seeking system and to calculate the real north angle accurately the principles of the system and the algorithm of singular value decomposition(SVD) are introduced. The factors influencing the measuring precision are also analyzed. Then the algorithm is adopted to fit curves. Experimental results indicate that the singular value decomposition is very precise for its error sum is 1.1102V and the squared error is 2.8mV. Moreover for phase angle measurement measured six times in same direction the squared error is 24 (1). The method based on SVD can satisfy the system precision requirements of curve-fitting north seeking systems. 2011 IEEE.