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浏览/检索结果: 共23条，第1-10条 帮助

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Changes in soil bacterial abundance and diversity in response to drip irrigation to Establish plant communities on highly saline Lands in north China 期刊论文  OAI收割
CATENA, 2025, 卷号: 252, 页码: 108874
作者:  Zhu, Wendong;  Kang, Yaohu;  Zhu, Yuanpeng;  Wan, Shuqin
  |  收藏  |  浏览/下载：18/0  |  提交时间：2025/04/21
Impacts of Urban Green Space on Land Surface Temperature from Urban Block Perspectives 期刊论文  OAI收割
REMOTE SENSING, 2022, 卷号: 14, 期号: 18, 页码: 17
作者:  An, Hongmin;  Cai, Hongyan;  Xu, Xinliang;  Qiao, Zhi;  Han, Dongrui
  |  收藏  |  浏览/下载：28/0  |  提交时间：2022/11/09
COMPOSITION OPERATORS BETWEEN BLOCH TYPE SPACES IN THE UNIT BALL 期刊论文  OAI收割
ACTA MATHEMATICA SCIENTIA, 2014, 卷号: 34, 期号: 1, 页码: 73-81
作者:  Dai, Jineng;  Ouyang, Caiheng
收藏  |  浏览/下载：32/0  |  提交时间：2015/06/24
Simulation test system of CCD signal processor based on FPGA (EI CONFERENCE) 会议论文  OAI收割
2nd International Conference on Mechatronics and Applied Mechanics, ICMAM 2012, December 8, 2012 - December 9, 2012, Taiwan
作者:  Zhang D.;  Liu D.-B.;  Zhang D.
收藏  |  浏览/下载：42/0  |  提交时间：2013/03/25
Simulation test system of CCD signal processor based on FPGA is proposed. Field-programmable gate array (FPGA) is applied as control processing core and used in the aerospace upgrade screening of industrial grade signal processor. The system functional composition and working principle were introduced in detail. Actually evaluation and testing system was completed with integrating the forty signal processor in a single board. The system has been successfully applied in the dynamic build-in screening test of industrial grade signal processor XRD98L63  the system work stably and reliability. Test result is zero on the nonconforming product rate  satisfying the qualification that single batch screening nonconforming rate is less than 5%  build-in screening of industrial grade components for the space load applications is implemented. (2013) Trans Tech Publications  Switzerland.  
Physical layer design for free space optical communication (EI CONFERENCE) 会议论文  OAI收割
2012 International Conference on Control Engineering and Communication Technology, ICCECT 2012, December 7, 2012 - December 9, 2012, Shenyang, Liaoning, China
作者:  Wang H.;  Zhang Q.;  Guo J.;  Guo J.;  Wang H.
收藏  |  浏览/下载：34/0  |  提交时间：2013/03/25
A small size Free Space Optical Communication System is introduced  including the hardware and the hardware specified physical layer protocol. In detail  the rapid synchronization method to reduce the handshake bandwidth requirement is demonstrated. The hardware of the system includes the laser driver system  the signal amplifying and shaping system  the data interface system. The hardware specified physical layer protocol is used to interface the outer data  serialize and deserialize the data stream  check transmission errors and schedule the data transmission. The overall system is a FIFO-like system and the user can use it as if he's operating a FIFO. The system is designed mainly for terrestrial FSO link whose signal channel is the atmosphere. Due to the complex composition and activity of the atmosphere  this signal channel brings in great influence on the transmitting laser in it  for example  the absorption and scattering of the atmosphere molecules and aerosols  the scintillation of received laser power caused by the turbulence of the atmosphere  all of which results in a much higher Bit Error Rate (BER) of the communication system than wired communication systems leading to frequent resynchronization. In our system  the sampling clock is generated locally using multi-phase sampling technique rather than PLLbased clock recovery  which helps to rapid synchronization. 2012 IEEE.  
COMPACT DIFFERENCES OF COMPOSITION OPERATORS ON HOLOMORPHIC FUNCTION SPACES IN THE UNIT BALL 期刊论文  OAI收割
ACTA MATHEMATICA SCIENTIA, 2011, 卷号: 31, 期号: 5, 页码: 1679-1693
作者:  Jiang Liangying;  Ouyang Caiheng
收藏  |  浏览/下载：29/0  |  提交时间：2015/06/25
Composition operators between Bloch type spaces and Zygmund spaces in the unit ball 期刊论文  OAI收割
PROCEEDINGS OF THE INDIAN ACADEMY OF SCIENCES-MATHEMATICAL SCIENCES, 2011, 卷号: 121, 期号: 3, 页码: 327-337
作者:  Dai, Jineng;  Ouyang, Caiheng
收藏  |  浏览/下载：27/0  |  提交时间：2015/06/25
COMPACT COMPOSITION OPERATORS ON GENERALIZED LIPSCHITZ SPACES 期刊论文  OAI收割
ACTA MATHEMATICA SCIENTIA, 2011, 卷号: 31, 期号: 4, 页码: 1347-1356
作者:  Dai Jineng;  Ouyang Caiheng
收藏  |  浏览/下载：21/0  |  提交时间：2015/06/25
The research on statistical properties of TDI-CCD imaging noise (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Gu Y.-Y.; Shen X.-H.; He G.-X.
收藏  |  浏览/下载：30/0  |  提交时间：2013/03/25
TDI-CCD can improve the sensitivity of space camera without any degradation of spatial resolution which is widely used in aerospace imaging devices. The article describes the basic working principle and application characteristics of TDI-CCD devices  analyses the composition of TDI-CCD imaging noise  and propose a new method to analyze TDI-CCD imaging noise with statistical probability distribution. In order to estimate the distribution of gray values affect by noise we introduced the concept of skewness and kurtosis. We design an experiment using constant illumination light source  take image with TDI-CCD working at different stage such as stage 16  stage 32  stage 48  stage 64 and stage 96  analyse the characteristics of image noise with the method we proposed  experimental results show that the gray values approximately meet normal distribution in large sample cases. 2011 SPIE.  
Design of motion compensation mechanism of satellite remote sensing camera (EI CONFERENCE) 会议论文  OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Space Exploration Technologies and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Gu S.; Yan Y.; Xu K.; Jin G.
收藏  |  浏览/下载：49/0  |  提交时间：2013/03/25
With the development of aerospace remote sensing technology  the ground resolution of remote sensing camera enhances continuously. Since there is relative motion between camera and ground target when taking pictures  the target image recorded in recording media is moved and blurred. In order to enhance the imaging quality and resolution of the camera  the image motion had to be compensated. In order to abate the effect of image motion to image quality of space camera and improve the resolution of the camera  the compensation method of image motion to space camera is researched. First  the reason of producing drift angle and adjustment principle are analyzed in this paper. This paper introduce the composition and transmission principle of image motion compensation mechanism. Second  the system adopts 80C31 as controller of drift angle  and adopts stepping motor for actuators  and adopts absolute photoelectric encoder as the drift Angle measuring element. Then the control mathematical model of the image motion compensation mechanism are deduced  and it achieve the closed-loop control of the drift angle position. At the last  this paper analyses the transmission precision of the mechanism. Through the experiment  we measured the actual precision of the image motion compensation mechanism  and compared with the theoretical analysis. There are two major contributions in this paper. First  the traditional image motion compensation mechanism is big volume and quality heavy. This has not fit for the development trend of space camera miniaturization and lightweight. But if reduce the volume and quality of mechanism  it will bring adverse effects for the precision and stiffness of mechanism. For this problem  This paper designed a image motion compensation that have some advantages such as small size  light weight at the same time  high precision  stiffness and so on. This image motion compensation can be applicable to the small optics cameras with high resolution. Second  the traditional mechanism control need to corrected  fitting and iterative for the control formula of mechanism. Only in this way  we can get the optimal control mathematical model. This paper has high precision of the control formula derived. It can achieve the high precision control without fitting  It also simplify the difficulty of control mathematical model establishment. This paper designed the range of adjusting of image motion compensation mechanism between -5 +5. Based on choosing-5  -4  -3  -2  -1  0  +1  +2  +3  +4  +4 as the expectation value of the imaginary drift angle  we get ten groups of the fact data in adjusting drift angle measured. The test results show that the precision of the drift angle control system can be achieved in 1. It can meet the system requirements that the precision of the control system is less than 3'  and it can achieve the high-precision image motion compensation. 2011 SPIE.  
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