中国科学院机构知识库网格系统: 检索

The main and added effects of heat on mortality in 33 Chinese cities from 2007 to 2013 期刊论文 OAI收割
FRONTIERS OF ENVIRONMENTAL SCIENCE & ENGINEERING, 2023, 卷号: 17, 期号: 7, 页码: 81
作者: Niu, Yanlin; Yang, Jun; Zhao, Qi; Gao, Yuan; Xue, Tao

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收藏 | 浏览/下载：17/0 | 提交时间：2024/01/04

Heat Added effect Vulnerable population Main effect Mortality

塔里木河干流区土地利用/覆被变化及其生态环境效应[J] 期刊论文 OAI收割
地理科学, 2012, 卷号: 2, 页码: 244-250
作者: 赵锐锋; 姜朋辉; 陈亚宁; 石培基; 潘竟虎

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收藏 | 浏览/下载：13/0 | 提交时间：2017/12/29

土地利用/覆被变化转移矩阵生态环境效应塔里木河干流 Land Use/cover Change Conversion Matrix Eco-environment Effect The Main Stream Of Tarim River

The lightweight design of the inner framework of the opto-electronic stabilization platform based on finite element analysis (EI CONFERENCE) 会议论文 OAI收割
2011 IEEE 18th International Conference on Industrial Engineering and Engineering Management, IE and EM 2011, September 3, 2011 - September 5, 2011, Changchun, China
Zou Q.; Ma H.-L.; Hu Y.; Ding J.-W.

收藏 | 浏览/下载：26/0 | 提交时间：2013/03/25

The airborne opto-electronic stabilization platform should have the characteristics of high requirements for stability tracking accuracy and lightweight. In order to verify the rationality of the main load-bearing structure the inner-gimbal finite element analysis was performed. Because of the poor working conditions of the airborne opto-electronic stabilization platform and the wide range of working temperature variation -45 C 60 C according to the actual working environment air-resistance and temperature were added to the loads of the inner-gimbal in analysis. What's more based on the analysis results lightweight design was performed to the initial model and 64.37% of mass was decreased. The remarkable effect was obtained. This research is going to be instructive to design and production of the airborne opto-electronic stabilization platform in the future. 2011 IEEE.

Research on the the device of non-angular vibration for opto-electronic platform (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Smart Structures and Materials in Manufacturing and Testing, April 26, 2010 - April 29, 2010, Dalian, China
An Y.; Song C.-P.; Kuang R.-J.; Jin G.

收藏 | 浏览/下载：29/0 | 提交时间：2013/03/25

The opto-electronic platform is the main equipment for aviation reconnaissance. It is a surveillance system with the function of search recognition orientation and tracking by opto- electronic instruments. It is made up of opto-electronic instruments which are used to get high quality image and stabilization tracking system to control stabilization and gesture of platform for exact tracking. The opto-electronic platform purpose is to achieve high quality image. Besides the impact of optic system the image quality of the system is influenced greatly in the vibration environment. The research worked by Zhao peng which demonstrated the affection caused by angular vibration was worse than which caused by line vibration and what was multiplied direct ratio with plane altitude. So it is necessary to design a new device which could be used widely and has good angular vibration isolation effect. According to the theory of parallelogram the non-angular vibration device had been designed with spatial links and the theory of non-angular vibration was analyzed. The three-dimensional model was set with UG the analysis was done by ADAMS/vibration software. The acceleration and displacement response of the device in each direction was calculated by inspiriting it with sine wave of the acceleration in three directions and the stiffness and damp were studied. All the work prove the design principle of the device is reasonable and the device is adopted to keep the platform motion moving horizontally at the meantime the device is good at isolating vibration in all directions. 2010 SPIE.

Design of high-speed low-noise pre-amplifier for CCD camera (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology, April 26, 2010 - April 29, 2010, Dalian, China
作者: Zhang S.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

Pre-amplifier circuit is critical for the noise performance of the high speed CCD camera. Its main functions are amplification and impedance transform. The high speed and low noise pre-amplifier of CCD camera is discussed and designed in this paper. The high speed and low noise operational amplifier OPA842 is adopted as the main part. The gain-set resistors for the amplifier are designed optimally. The different precision gain-set resistors are swept using Monte Carlo method. CCD video signal which has high DC offset voltage is AC coupled to the amplifier. The output signal of the amplifier is source terminated using 50 ohms matching resistor so as to transmit the video signal through coaxial cable. When the circuit works in high speed the PCB will have important effect to circuit performance and can even cause the amplifier unstable due to the parasitic problem of PCB. So the parasitic model of the PCB is established and the PCB layout design issues are also presented. The design result shows that the pre-amplifier can be used in the camera whose pixel rate could be up to 40 MHz and its input referred noise density is about 3 nV/Hz 1/2. 2010 Copyright SPIE - The International Society for Optical Engineering.

High accuracy star image locating and imaging calibration for star sensor technology (EI CONFERENCE) 会议论文 OAI收割
6th International Symposium on Precision Engineering Measurements and Instrumentation, August 8, 2010 - August 11, 2010, Hangzhou, China
作者: Wang Y.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

Today aircraft attitude measurement technology plays an important role in an aircraft system because it can provide orientation for aircraft in action. Lately star sensor technology used in aircraft attitude measurement has become more and more popular because of its high accuracy light weight without attitude accumulation errors and other advantages. There are three main steps for star sensor to measure aircraft attitude star image locating star identification and attitude tracking. The latter two steps are based on the accuracy of star image locating. So it's critical to make efforts to advance the accuracy of star image locating. Some imaging errors such as spherical aberration or coma aberration also have negative effect on the accuracy of star image locating of which the effect is necessarily reduced as well. At the beginning of this article the structure of star sensor hardware is introduced. Secondly three methods for star image locating are described specifically which are traditional centroid method Gauss quadric fitting method and improved Gauss quadric fitting method. Subsequently an imaging calibration method is described for the purpose of reducing the effect of imaging errors. Finally the experiment shows that the accuracy of the star sensor is 2-arc-second. 2010 SPIE.

Driving and image enhancement for CCD sensing image system (EI CONFERENCE) 会议论文 OAI收割
2010 3rd IEEE International Conference on Computer Science and Information Technology, ICCSIT 2010, July 9, 2010 - July 11, 2010, Chengdu, China
Zhang M.; Ren J.

收藏 | 浏览/下载：26/0 | 提交时间：2013/03/25

The paper designs a driving circuit of high sensitive wide dynamic for CCD sensing imaging system which adopts a Dalsa-made high resolution full-frame 33-mega pixels area CCD FTF5066M. Field Programmable Gate Array (FPGA) is used as the main device to accomplish the timing design of the circuits and power driver control of the sensor. By using the Correlated Double Sampling (CDS) technique the video noise is reduced and the SNR of the system is increased. The output rate of the imaging system designed with integrated chip can reach to 1.3 frames per second through bi-channel output. We use the histogram specification to adjust the brightness of the captured image. And then use the median filtering to suppress the noise. The traditional gray mean gradient (GMG) and the objective evaluation method based on Human Visual System (HVS) used to verify the effect of image enhancement. 2010 IEEE.

Modulation transfer function measurement of sampled imaging systems in field test (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
作者: Yang L.; Zhang J.; Zhang J.; Zhang J.; Wang J.

收藏 | 浏览/下载：25/0 | 提交时间：2013/03/25

A digital mirror device (DMD) based light projector was developed as the target generator in modulation transfer function (MTF) measurement. In order to overcome the sampling-scene phase effect in MTF measurement of sampled imaging systems a method using random targets is introduced to yield a phase-averaged MTF. The main potential problem of implementing this method is the fact that the stationary assumption of the random targets may be vitiated in practical measurement especially in field test due to the ill condition. We provide an efficient model-independent way of analyzing and isolating the spectral contents arising from these additional contributions to MTF measurement. Algorithms with adaptive parameter selection were also developed for spectral estimation of the test image in order to overcome the challenge brought by the size limit of the test matrices for one certain field of view derived from the isoplantic region. The MTF measurement of a CCD video imager is used to demonstrate the measurement technique and illustrate the benefits over other methods. In order to validate the results comparisons have been made between MTF measurements of imager implemented using this method and bar target direct measurements. 2010 Copyright SPIE - The International Society for Optical Engineering.

Analysis of impact of gyroscope synthetical error on an electric-optical stabilized control system (EI CONFERENCE) 会议论文 OAI收割
3rd International Conference on BioMedical Engineering and Informatics, BMEI 2010, October 16, 2010 - October 18, 2010, Yantai, China
作者: Zhang X.; Zhang X.; Zhang X.; Jiang H.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

As one of the key components on a seeker EO stabilized platform on a missile gyroscope is directly relative to errors of servo systems. Main errors of gyro such as bias drift and scale factor nonlinearity are added to a servo system the result is analyzed to illuminated that how a gyro has effect on a seeker servo system. With the mathematical models of a gyro and a seeker the principle of choosing a gyro is theoretically deduced first and then two gyros model with different main parameters are added into the same gimbals model the errors of servo systems are compared to prove the deduction. Final conclusion is helpful for choosing proper gyros in a seeker servo system. 2010 IEEE.

Directional multiscale edge detection using the contourlet transform (EI CONFERENCE) 会议论文 OAI收割
2010 IEEE International Conference on Advanced Computer Control, ICACC 2010, March 27, 2010 - March 29, 2010, 445 Hoes Lane - P.O.Box 1331, Piscataway, NJ 08855-1331, United States
作者: Jin L.-X.; Han S.-L.; Zhang R.-F.

收藏 | 浏览/下载：33/0 | 提交时间：2013/03/25

Wavelet multiresolution analysis allows us to detect edges at different scales also to obtain other important aspects of the extracted edges. However due to the usual two-dimensional tensor product wavelet transform is not optimal for representing images. The main problem in edge detection using wavelet transform is that it can only capture point-singularities and the extracted edges are not continuous. In order to solve that problem we propose a new image edge detection method based on the contourlet transform. The directional multiresolution representation Contourlet takes advantages of the intrinsic geometrical structure of images and is appropriate for the analysis of the image edges. Using the modulus maxima detection an image edge detection method based on contourlet transform is proposed. To suppress the image noise effect on edge detection the scale multiplication in contourlet domain is also proposed. Through real images experiments the proposed edge detection method's performance for the extracted edges is analyzed and compared with other two edge detection methods. The experiment result proves that the proposed edge detection method improves over wavelet-based techniques and Canny detector and also works well for noisy images. 2010 IEEE.