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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：60/0  |  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.  
Evolution of the germanium-oxygen coordination number in lithium-lead-germanate glasses 期刊论文  OAI收割
JOURNAL OF NON-CRYSTALLINE SOLIDS, 2016, 卷号: 437, 页码: 10-16
作者:  Rada, M;  Aldea, N;  Wu ZH(吴忠华);  Zhang J(张静);  Wu, ZH
  |  收藏  |  浏览/下载：19/0  |  提交时间：2017/07/24
Influence of polychromaticity on particle structure determination in small-angle X-ray scattering 期刊论文  OAI收割
JOURNAL OF APPLIED CRYSTALLOGRAPHY, 2015, 卷号: 48, 页码: 1935-1942
作者:  Wang WJ(王文佳);  Chang GC(常广才);  Zhang LH(张连辉);  Dong YH(董宇辉);  刘鹏(多)
收藏  |  浏览/下载：32/0  |  提交时间：2016/04/18
Effect of synthetic pathways on the phase transition and side-chain crystallization behavior of alkyl-substituted cellulose ethers 期刊论文  OAI收割
polymer chemistry, 2014, 卷号: 5, 期号: 13, 页码: 4105-4114
Chen, Xi; Zheng, Nan; Wang, Qiao; Liu,Lingzhi; Men,Yongfeng
收藏  |  浏览/下载：34/0  |  提交时间：2015/07/14
The research of digltal CR medicine image adapitive enhancement method (EI CONFERENCE) 会议论文  OAI收割
4th International Conference on Mechanical and Electrical Technology, ICMET 2012, July 24, 2012 - July 26, 2012, Kuala Lumpur, Malaysia
Ming-Hui Z.; Yao-Yu Z.
收藏  |  浏览/下载：67/0  |  提交时间：2013/03/25
Digital CR medicine radiation image is in doctor's favor and has became medicine imaging technology new hot spot because of its high gray contrast  powerful computer disposal function  little radiation dosage  non-film diagnosis  different area consultation. But degradation of digital X-ray medical image such as low contrast and blurring during radiographic imaging  caused by complexity of body tissue and effects of X-ray scattering and electrical noise etc.  can worsen the results of analysis and diagnosis. So it is usually needed that CR medicine image is enhanced to improve its vision quality  and easy to doctor's more accurate diagnosis. The general enhancement algorithms over enhancing the contrast and lose image details  aiming at the defects  an enhancement algorithm for CR image is proposed based on the ratio of deviation to mean of domain. The arithmetic enhance CR image edge details by adjusting factor K based on the ratio of deviation to mean of domain of CR image. Experiment results demonstrate that the algorithm enhances CR image detail and CR image enhanced has good visual effect  the adaptive enhancement method is fit for CR medicine image. (2012) Trans Tech Publications  Switzerland.  
Direct methods beyond small-molecule crystallography 期刊论文  OAI收割
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE, 2010, 卷号: 207, 期号: 12, 页码: 2621
Fan, HF
收藏  |  浏览/下载：26/0  |  提交时间：2013/09/17
Structures of Co90Fe10/Cu multilayers determined by X-ray anomalous scattering measurements 期刊论文  OAI收割
THIN SOLID FILMS, 2006, 卷号: 496, 期号: 2, 页码: 571-575
作者:  An, YK;  Dai, B;  Mai, ZH;  Cai, JW;  Wu, ZH
收藏  |  浏览/下载：16/0  |  提交时间：2016/06/28
Elemental distribution at the interfaces of Ni70Co30/Cu magnetic multilayers by X-ray anomalous scattering 期刊论文  OAI收割
HIGH ENERGY PHYSICS AND NUCLEAR PHYSICS-CHINESE EDITION, 2005, 卷号: 29, 页码: #REF!
作者:  An, YK;  Dai, B;  Mai, ZH;  Cai, JW;  Wu, ZH
收藏  |  浏览/下载：15/0  |  提交时间：2016/04/11
ELECTRONIC-STRUCTURE AND SYMMETRY OF THE ITINERANT STATES IN HIGH-TC SUPERCONDUCTORS 期刊论文  OAI收割
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 1993, 卷号: 32, 页码: 581
BIANCONI, A; POMPA, M; TURTU, S; PAGLIUCA, S; LAGARDE, P; FLANK, AM; LI, CX
收藏  |  浏览/下载：27/0  |  提交时间：2013/09/17