中国科学院机构知识库网格系统: 检索

An Improved Altimeter in-Orbit Range Noise-Level Estimation Approach Based on Along-Track Differential Method 期刊论文 OAI收割
REMOTE SENSING, 2022, 卷号: 14, 期号: 24, 页码: 19
作者: Liu, Xiaonan; Kong, Weiya; Sun, Hanwei; Xu, Yongsheng; Lu, Yaobing

|

收藏 | 浏览/下载：12/0 | 提交时间：2023/11/16

altimeter in-orbit noise level along-track differential method power spectrum density analysis Sentinel-6 ocean swells

The application of ratio correction method in radio spectrum 会议论文 OAI收割
Changsha, Hunan, China, 2020-12-18
作者: Zhang, Yankun; Li, Mingyue; He, Lesheng; Dong L(董亮); Wang M(汪敏)

|

收藏 | 浏览/下载：33/0 | 提交时间：2021/10/19

Discrete digital power spectrum Ratio correction method Spectral lines

Establishment of NmF2 empirical model in the northern hemisphere based on COSMIC occultation data 期刊论文 OAI收割
SCIENCE CHINA-TECHNOLOGICAL SCIENCES, 2014, 卷号: 57, 期号: 2, 页码: 339-344
作者: Niu Jun; Fang HanXian; Weng LiBin

收藏 | 浏览/下载：34/0 | 提交时间：2014/07/14

empirical NmF2 model empirical orthogonal function decomposition local wavelet power spectrum method least squares method

Improved method of target detection on optoelectronic hybrid joint transform correlator in cluttered scences (EI CONFERENCE) 会议论文 OAI收割
2011 3rd International Conference on Mechanical and Electronics Engineering, ICMEE 2011, September 23, 2011 - September 25, 2011, Hefei, China
作者: Yang L.; Yang L.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

A classical joint transform correlator (JTC) usually yields large correlation sidelobes as well as a large correlation peak width strong zero-order peak and low diffraction efficiency which make the detection ability of JTC lower. To overcome these difficulties firstly a joint power spectrum (JPS) subtraction technique in Fourier plane was proposed where reference image power spectrum and object image power spectrum are subtracted from the JPS before inverse Fourier-transform operation it is obvious that the modified JPS removes the zero-order term. Secondly a fringe-adjusted filter (FAF) was presented to suppress sidelobes and noises. The modified JPS is multiplied by a FAF before the inverse Fourier-transform operation to obtain the cross-correlation peak. Computer simulations demonstrated the improved method can obviously remove zero-order diffraction and effectively suppress the sidelobes and noises compared with classic JTC and then improve the detection ability for JTC. Experimental results presented the sharp correlation peak and also confirmed the method effectiveness. (2012) Trans Tech Publications Switzerland.

Spectral analysis on sub-tidal variability of salinity in Modaomen waterway of Pearl River estuary, China 会议论文 OAI收割
1st International Conference on Energy and Environmental Protection, ICEEP 2012, Hohhot, China, JUN 23-24, 2012
作者: Chen YY(陈苑盈)

收藏 | 浏览/下载：33/0 | 提交时间：2013/02/26

Estuaries Rivers Spectrum analysis Tides Time series Modaomen waterway Pearl River Pearl River estuary Phase analysis Power spectrum method Salinity Sub-tidal Tidal ranges

Design and demonstration of micro multi-step mirrors and light source in micro FTIR (EI CONFERENCE) 会议论文 OAI收割
6th IEEE International Conference on Nano/Micro Engineered and Molecular Systems, NEMS 2011, February 20, 2011 - February 23, 2011, Kaohsiung, Taiwan
Liang Z.; Fu J.; Feng C.; Liang J.

收藏 | 浏览/下载：43/0 | 提交时间：2013/03/25

To obtain high resolution high signal-to-noise ratio (SNR) high reliability and real time in wide spectral range we study the space modulation Micro Fourier Transform Spectrometer (FTS) based on multi-step mirrors covering the spectral range of 3-5m and 8-12 m in theory and experiment. The influences of spectrum reconstruction caused by the diffraction and extended light source in Fourier Transform Infrared Spectrometer (FTIR) are analyzed. A method to reduce the noises in spectrum reconstruction and the relationship between coherent intensity and solid angle of light source are discussed. An extended light source with suitable size is chosen considering the requirement of SNR and spectrum resolving power in the optical design. Furthermore the fabrication of micro multi-step mirrors which is the core part of FTS is investigated. Three methods for fabricating multi-step micro mirrors are demonstrated. 2011 IEEE.

Improved peak power method for measuring frequency responses of photodetectors in a self-heterodyne system 期刊论文 iSwitch采集
Microwave and optical technology letters, 2010, 卷号: 52, 期号: 10, 页码: 2199-2203
作者: Wang, Li Xian; Zhu, Ning Hua; Ke, Jian Hong; Li, Wei; Chen, Shuo Fu

收藏 | 浏览/下载：33/0 | 提交时间：2019/05/12

Distributed bragg reflector laser Frequency response Photodetector Time-resolved spectrum Peak power method

IMPROVED PEAK POWER METHOD FOR MEASURING FREQUENCY RESPONSES OF PHOTODETECTORS IN A SELF-HETERODYNE SYSTEM 期刊论文 OAI收割
microwave and optical technology letters, 2010, 卷号: 52, 期号: 10, 页码: 2199-2203
Wang LX (Wang Li Xian); Zhu NH (Zhu Ning Hua); Ke JH (Ke Jian Hong); Li W (Li Wei); Chen SF (Chen Shuo Fu); Xie LA (Xie Liang)

收藏 | 浏览/下载：112/1 | 提交时间：2010/09/07

distributed Bragg reflector laser frequency response photodetector time-resolved spectrum peak power method

Athermal design of hybrid refractive/harmonic diffractive optical system for far-infrared multi-band (EI CONFERENCE) 会议论文 OAI收割
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, November 19, 2008 - November 21, 2008, Chengdu, China
作者: Liu Y.; Liu Y.; Zhang H.; Zhang H.; Sun Q.

收藏 | 浏览/下载：33/0 | 提交时间：2013/03/25

In order to get enough information about the target avoid big chromatic aberration as a result of wide spectrum and the complexity of optical system and adapt different special environment temperature a hybrid refractive/harmonic diffractive optical system in far-infrared multi-band is described in the paper. This diffractive optical system has been designed an athermalized multi-band imaging system with harmonic diffractive element in 15-50m spectrum based on larger 1dispersion capability and particular thermal dispersive power of harmonic diffractive element. Then at the temperature range from 0C to 40C this design can simultaneously meet with all requirements of the imaging system in five harmonic wave bands including15.8-16.2m 18.5-20m 23-25m 30.5-33.5m and 46-50m. In each harmonic wave band the magnification changes as a function of wavelength which creates image registration error. To compensate this shortcoming a zoom optical system is designed with three lenses by means of optical two- component method. The design results show that the hybrid refractive/harmonic diffractive optical system can realize athermalized and achromatic design and the zoom optical system makes half image height at 3.53mm in every harmonic wave band and still realizes aberration compensation action. In the five harmonic wave bands each optical transfer function approaches the diffraction limit at ambient temperature range of 0C to 40C. Finally the system realizes the requirements of portability mini-type and ease for fabrication. 2009 SPIE.

A study of the light curve periodic behavior of BL Lac object S5 0716+714 期刊论文 OAI收割
ACTA PHYSICA SINICA, 2007, 卷号: 56, 期号: 7, 页码: 4305
作者: Zhang HJ(张皓晶); Zhang X(张雄)

|

收藏 | 浏览/下载：12/0 | 提交时间：2021/12/06

UNEQUALLY-SPACED DATA RAY-LOUD BLAZARS OPTICAL VARIABILITY GAMMA-RAY CCD PHOTOMETRY BLACK-HOLE S5-0716+714 OJ-287 BL Lac object S5 0716+714 light curve variation period method of power spectrum