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	Photometric Study and Absolute Parameter Estimation of Six Totally Eclipsing Contact Binaries 期刊论文 OAI收割 Astronomical Journal, 2021, 卷号: 162, 期号: 1, 页码: 13 作者: Li, Kai; Xia, Qi-Qi; Kim, Chun-Hwey; Gao, Xing; Hu, Shao-Ming \| 收藏 \| 浏览/下载：26/0 \| 提交时间：2022/06/30 low-mass-ratio light-curve analysis ursae-majoris system thermal relaxation oscillation radial-velocity curves flip-flop activity short-period limit rt leonis minoris uma-type binaries physical parameters Astronomy & Astrophysics
	An underlying clock in the extreme flip-flop state transitions of the black hole transient Swift J1658.2-4242 期刊论文 OAI收割 Astronomy and Astrophysics, 2020, 卷号: 641, 页码: A101 作者: HXMT \| 收藏 \| 浏览/下载：57/0 \| 提交时间：2022/02/08 accretion accretion disks black hole physics X-rays: binaries time Astrophysics - High Energy Astrophysical Phenomena Abstract: Aims: Flip-flops are top-hat-like X-ray flux variations, which have been observed in some transient accreting black hole binary systems, and feature simultaneous changes in the spectral hardness and the power density spectrum (PDS). They occur at a crucial time in the evolution of these systems, when the accretion disc emission starts to dominate over coronal emission. Flip-flops remain a poorly understood phenomenon, so we aim to thoroughly investigate them in a system featuring several such transitions. Methods: Within the multitude of observations of Swift J1658.2-4242 during its outburst in early 2018, we detected 15 flip-flops, enabling a detailed analysis of their individual properties and the differences between them. We present observations by XMM-Newton, NuSTAR, Astrosat, Swift, Insight-HXMT, INTEGRAL, and ATCA. We analysed their light curves, searched for periodicities, computed their PDSs, and fitted their X-ray spectra, to investigate the source behaviour during flip-flop transitions and how the interval featuring flip-flops differs from the rest of the outburst. Results: The flip-flops of Swift J1658.2-4242 are of an extreme variety, exhibiting flux differences of up to 77% within 100 s, which is much larger than what has been seen previously. We observed radical changes in the PDS simultaneous with the sharp flux variations, featuring transitions between the quasi-periodic oscillation types C and A, which have never been observed before. Changes in the PDS are delayed, but more rapid than changes in the light curve. Flip-flops occur in two intervals within the outburst, separated by about two weeks in which these phenomena were not seen. Transitions between the two flip-flop states occurred at random integer multiples of a fundamental period of 2.761 ks in the first interval and 2.61 ks in the second. Spectral analysis reveals the high and low flux flip-flop states to be very similar, but distinct from intervals lacking flip-flops. A change of the inner temperature of the accretion disc is responsible for most of the flux difference in the flip-flops. We also highlight the importance of correcting for the influence of the dust scattering halo on the X-ray spectra.
	Novel fast measurement method of twist angle and optical retardation of liquid crystal display (EI CONFERENCE) 会议论文 OAI收割 Asia Display 2007, AD'07, March 12, 2007 - March 16, 2007, Shanghai, China Huang X.; Lu Y.-T.; Kong X.-J.; Jing H.; Fu G.-Z.; Jin H. 收藏 \| 浏览/下载：14/0 \| 提交时间：2013/03/25 A novel method is proposed to measure twist angle and optical retardation of liquid crystal display in this paper. The new method which is one of single-wavelength methods has three characteristics introducing a method of measuring the total intensity ratio of the transmitted light to eliminate the influence of absorption by the polarizer using circularly and homogeneously aligned LC cell (CH-LC) as a unique polarization-converting device analyzer using variable sector diaphragm and photodetector to detect the total intensity of transmitted light whose original polarization direction is continuously changed from 0 to arbitrary angle CH-LC liquid crystal display and so on. The twist angle () and optical retardation (nd) can be derived by using Jones matrix analysis and a curve fitting where and nd are fitting parameters. Experiment proved the results are accurate the process of operation is fast the devices are economical.