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	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：61/0 \| 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.
	A SEMI-ANALYTIC METHOD TO SPEED UP THE CONVERGENCE OF SUCCESSIVE ORDER OF SCATTERING MODEL 会议论文 OAI收割 2012 Ieee International Geoscience and Remote Sensing Symposium (Igarss) Hou, Weizhen; Yin, Qiu; Li, Zhengqiang; Liu, Yalan 收藏 \| 浏览/下载：16/0 \| 提交时间：2014/12/07 Approximation methods convergence curve fitting remote sensing scattering ATMOSPHERE
	Study on resonance absorption raman scattering in i2 liquid-core optical fiber (EI CONFERENCE) 会议论文 OAI收割 Nonlinear Optics: Technologies and Applications, November 12, 2007 - November 13, 2007, Beijing, China 作者: Fang W.; Yi W. 收藏 \| 浏览/下载：23/0 \| 提交时间：2013/03/25 The Raman scattering of I2 liquid-core optical fiber under the condition of resonance absorption in liquid-core optical fiber is studied in this paper. Iodine is dissolved in transparent benzene to make solution of I2 in benzene and the absorption coefficients of the solution are measured at certain wavelengths. The absorption curve can be divided into non-resonance absorption region pre-resonance absorption region strict resonance absorption region and post-resonance absorption region respectively. Resonance absorption Raman scattering experiments are conducted by a 532 nm frequency-doubled Nd:YVO4 laser and the wavelength is in the strict resonance absorption region of solution of I2 in benzene. Compared with I2 the absorption of benzene can be neglected. Non-resonance Raman scattering of the solution is performed using a 632.8 nm He-Ne laser and no spectrum lines of I2 are found. The study demonstrates that there is one spectrum line of I2 in the Raman scattering spectrum in the I 2 liquid-core optical fiber but this line is not found in the spectrum of the non-resonance and resonance absorption Raman scattering of I2 solution in benzene using absorption cell. The experiments proved that I 2 Raman scattering is greatly enhanced by using both resonance absorption and liquid-core optical fiber.
	Preliminary transformation on experimental data of small angle X-ray scattering 期刊论文 OAI收割 HIGH ENERGY PHYSICS AND NUCLEAR PHYSICS-CHINESE EDITION, 2001, 卷号: 25, 页码: #REF! 作者: Zhao H(赵辉); Dong BZ(董宝中); Rong LX(荣利霞); Wang J(王俊); Zhao, H 收藏 \| 浏览/下载：19/0 \| 提交时间：2016/04/12 small angle X-ray scattering data transformation scattering curve