中国科学院机构知识库网格系统: 检索

Stress Drops of Intermediate-Depth and Deep Earthquakes in the Tonga Slab 期刊论文 OAI收割
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 2022, 卷号: 127, 期号: 10, 页码: 23
作者: Tian, Dongdong; Wei, S. Shawn; Wang, Wei; Wang, Fan

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intermediate-depth and deep earthquakes Tonga subduction zone fluid-related embrittlement source spectra stress drops double seismic zone

Modeling of the source neutrons of D-T neutron generator based on in-situ depth profiling of tritium in the tritide target 期刊论文 OAI收割
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 2020, 卷号: 982
作者: Zhu, Qingjun; Bao, Jie; Chen, Wuhui; Huang, Kai

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收藏 | 浏览/下载：35/0 | 提交时间：2020/12/07

D-T neutron generator Neutronic experiment Tritium Alpha spectra Source neutrons

No pulsed radio emission during a bursting phase of a Galactic magnetar 期刊论文 OAI收割
Nature, 2020, 卷号: 587, 页码: 63-65
作者: HXMT

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收藏 | 浏览/下载：44/0 | 提交时间：2022/02/08

Astrophysics - High Energy Astrophysical Phenomena Abstract: Fast radio bursts (FRBs) are millisecond-duration radio transients of unknown physical origin observed at extragalactic distances^1-3. It has long been speculated that magnetars are the engine powering repeating bursts from FRB sources^4-13, but no convincing evidence has been collected so far¹⁴. Recently, the Galactic magnetar SRG 1935+2154 entered an active phase by emitting intense soft íray bursts¹⁵. One FRB-like event with two peaks (FRB 200428) and a luminosity slightly lower than the faintest extragalactic FRBs was detected from the source, in association with a soft íray/hard-X-ray flare^18-21. Here we report an eight-hour targeted radio observational campaign comprising four sessions and assisted by multi-wavelength (optical and hard-X-ray) data. During the third session, 29 soft-íray repeater (SGR) bursts were detected in íray energies. Throughout the observing period, we detected no single dispersed pulsed emission coincident with the arrivals of SGR bursts, but unfortunately we were not observing when the FRB was detected. The non-detection places a fluence upper limit that is eight orders of magnitude lower than the fluence of FRB 200428. Our results suggest that FRB-SGR burst associations are rare. FRBs may be highly relativistic and geometrically beamed, or FRB-like events associated with SGR bursts may have narrow spectra and characteristic frequencies outside the observed band. It is also possible that the physical conditions required to achieve coherent radiation in SGR bursts are difficult to satisfy, and that only under extreme conditions could an FRB be associated with an SGR burst.

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

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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.

Calculation of the wide-angle neutron spectra from the Be-9(d, xn) reaction in a thick beryllium target 期刊论文 OAI收割
CHINESE PHYSICS C, 2019, 卷号: 43, 期号: 5, 页码: 6
作者: Ding, Yan-Yan; Ma, Zhan-Wen; Huang, Zhi-Wu; Zhang, Ya-Ling; Wang, Jun-Run

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收藏 | 浏览/下载：82/0 | 提交时间：2019/11/10

neutron source Be-9(d, xn) reaction thick target wide-angle neutron spectra neutron angular distributions

Timing analysis of Swift J1658.2-4242's outburst in 2018 with Insight-HXMT, NICER and AstroSat 期刊论文 OAI收割
Journal of High Energy Astrophysics, 2019, 卷号: 24, 页码: 30-40
作者: HXMT

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收藏 | 浏览/下载：57/0 | 提交时间：2022/02/08

Accretion accretion disks Black hole physics X-rays: binaries: Swift J1658.2-4242 Astrophysics - High Energy Astrophysical Phenomena Abstract: We present the observational results from a detailed timing analysis of the black hole candidate Swift J1658.2-4242 during its 2018 outburst with the observations of Hard X-ray Modulation Telescope (Insight-HXMT), Neutron Star Interior Composition Explorer (NICER) and AstroSat in 0.1-250 keV. The evolution of intensity, hardness and integrated fractional root mean square (rms) observed by Insight-HXMT and NICER are presented in this paper. Type-C quasi-periodic oscillations (QPOs) observed by NICER (0.8-3.5 Hz) and Insight-HXMT (1-1.6 Hz) are also reported in this work. The features of the QPOs are analyzed with an energy range of 0.5-50 keV. The relations between QPO frequency and other characteristics such as intensity, hardness and QPO rms are carefully studied. The timing and spectral properties indicate that Swift J1658.2-4242 is a black hole binary system. Besides, the rms spectra of the source calculated from the simultaneous observation of Insight-HXMT, NICER and AstroSat support the Lense-Thirring origin of the QPOs. The relation between QPO phase lag and the centroid frequency of Swift J1658.2-4242 reveals a near zero constant when < 4Hz and a soft phase lag at 6.68 Hz. This independence follows the same trend as the high inclination galactic black hole binaries such as MAXI J1659-152.

Optical response of (InGa)(AsSb)/GaAs quantum dots embedded in a GaP matrix 期刊论文 OAI收割
Physical Review B, 2019, 卷号: 100, 期号: 19, 页码: 19
作者: P.Steindl; E.M.Sala; B.Alen; D.F.Marron; D.Bimberg

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收藏 | 浏览/下载：16/0 | 提交时间：2020/08/24

single-photon source,temperature-dependence,excitonic recombination,raman-spectra,oxygen donor,gaas,emission,luminescence,photoluminescence,localization,Materials Science,Physics

Fluorescence fingerprinting properties for exploring water-soluble organic compounds in PM2.5 in an industrial city of northwest China 期刊论文 OAI收割
ATMOSPHERIC ENVIRONMENT, 2018, 卷号: 184, 页码: 203-211
作者: Mu, Situ; Tan, Jihua; Hu, Jingnan; Xiao, Kang; Duan, Jingchun

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收藏 | 浏览/下载：41/0 | 提交时间：2019/06/21

Fluorescence properties Excitation-emission matrix spectra Aerosol source apportionment Urban environment

Study on response function model for γ-ray scintillation detector 期刊论文 OAI收割
ATOMIC ENERGY SCIENCE AND TECHNOLOGY, 2015, 卷号: 49, 期号: 8, 页码: 1354-1358
作者: Li Z(李哲); Zhang YW(张译文); Sun SF(孙世峰); Wang BY(王宝义); Wei L(魏龙)

收藏 | 浏览/下载：61/0 | 提交时间：2016/04/18

Detector response Gamma ray spectra Gamma-ray energy Interaction mechanisms Non-linear parameters Radiation source Response function models Weighted least squares

InAs/GaSb type-II superlattice grown by MOCVD for long-wavelength infrared detection 期刊论文 OAI收割
optoelectronics and advanced materials-rapid communications, 2011, 卷号: 5, 期号: 9, 页码: 1017-1020
作者: Xin, Liwei; Wang, Tao; Yang, Jin; Wang, Jingwei; Yin, Fei

收藏 | 浏览/下载：35/0 | 提交时间：2014/01/07

B1.InAs/GaSb A3.superlattices A3.source flux control A3.MOCVD A1.PL spectra