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	SUBSTRUCTURING PRECONDITIONERS FOR THE SYSTEMS ARISING FROM PLANE WAVE DISCRETIZATION OF HELMHOLTZ EQUATIONS 期刊论文 OAI收割 SIAM JOURNAL ON SCIENTIFIC COMPUTING, 2016, 卷号: 38, 期号: 4, 页码: A2232-A2261 作者: Hu, Qiya; Zhang, Haiyang \| 收藏 \| 浏览/下载：30/0 \| 提交时间：2018/07/30 Helmholtz equation large wave number plane wave discretization nonoverlapping domain decomposition parallel preconditioner iteration counts
	Measuring the system gain of the TDI CCD remote sensing camera (EI CONFERENCE) 会议论文 OAI收割 Advanced Materials and Devices for Sensing and Imaging II, November 8, 2004 - November 10, 2004, Beijing, China Ya-xia L.; Hai-ming B.; Jie L.; Jin R.; Zhi-hang H. 收藏 \| 浏览/下载：62/0 \| 提交时间：2013/03/25 The gain of a TDI CCD camera is the conversion between the number of electrons recorded by the TDI CCD and the number of digital units (counts) contained in the CCD image"[1]. TDI CCD camera has been a main technical approach for meeting the requirements of high-resolution and lightweight of remote sensing equipment. It is useful to know this conversion for evaluating the performance of the TDI CCD camera. In general a lower gain is better. However the resulting slope is the gain of the TDI CCD. We did the experiments using the Integration Sphere in order to get a flat field effects. We calculated the gain of the four IT-EI-2048 TDI CCD. The results and figures of the four TDI CCD are given. this is only true as long as the total well depth (number of electrons that a pixel can hold) of the pixels can be represented. High gains result in higher digitization noise. System gains are designed to be a compromise between the extremes of high digitization noise and loss of well depth. In this paper the mathematical theory is given behind the gain calculation on a TDI CCD camera and shows how the mathematics suggests ways to measure the gain accurately according to the Axiom Tech. The gains were computed using the mean-variance method also known as the method of photon transfer curves. This method uses the effect of quantization on the variance in the measured counts over a uniformly illuminated patch of the detector. This derivation uses the concepts of signal and noise. A linear fit is done of variance vs. mean
	Questions on pure luminosity evolution for elliptical galaxies 期刊论文 OAI收割 ASTROPHYSICAL JOURNAL, 1999, 卷号: 511, 期号: 2, 页码: 574-584 作者: He, P; Zhang, YZ; He, P , Chinese Acad Sci, Beijing Astron Observ, Beijing 100080, Peoples R China. \| 收藏 \| 浏览/下载：22/0 \| 提交时间：2012/08/29 High-redshift Galaxies Faint Blue Galaxies K-band Survey Number Counts Ccd Observations Field Galaxies Merger Model Telescope Population Universe