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Synchrotron-aided reconstruction of the prioniodinin multielement conodont apparatus (Hadrodontina) from the Lower Triassic of China 期刊论文  OAI收割
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY, 2020, 卷号: 560, 页码: 11
作者:  Sun, Zuoyu;  Liu, Shuang;  Ji, Cheng;  Jiang, Dayong;  Zhou, Min
  |  收藏  |  浏览/下载：24/0  |  提交时间：2021/03/09
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
  |  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 distances1-3. It has long been speculated that magnetars are the engine powering repeating bursts from FRB sources4-13, 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 flare18-21. 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.  
Introducing a special collection of papers in the Journal of High Energy Astrophysics on the Early Results of China's 1st X-ray Astronomy Satellite: Insight-HXMT 期刊论文  OAI收割
Journal of High Energy Astrophysics, 2020, 卷号: 27, 页码: 51-52
作者:  HXMT
  |  收藏  |  浏览/下载：51/0  |  提交时间：2022/02/08
Astrophysics - High Energy Astrophysical Phenomena  Abstract: Insight-HXMT is the first Chinese X-ray astronomical mission, launched successfully on June 15, 2017, from China's Jiuquan Satellite Launch Center. Insight-HXMT was designed to have a broad energy coverage in X-rays, from 1-250 keV, with excellent timing and adequate energy resolution at soft X-rays, and the largest effective area at hard X-rays. This allows, in particular, to observe bright sources like X-ray binaries (XRBs) in their bright/outburst states with high cadence and high statistics at hard and soft X-rays at once. It was then expected that the Insight-HXMT mission will bring us new insights regarding the characteristics of several source classes. Examples include characterizing High-Mass X-ray Binaries (HMXBs) and the outburst evolution of Low-Mass X-ray Binaries (LMXBs). For instance, in HMXB systems, the region around their Alfven radius that is responsible to determine whether accretion or propeller occurs, or the region around the NS magnetic pole where the intense X-rays are supposed to be produced are specially appealing targets of study. For the LMXBs, the evolution the outburst and the properties of the compact objects themselves are obvious priority targets for Insight-HXMT. Due to the broad coverage in energy, Insight-HXMT is specially well suited to study the influence of thermonuclear (type-I) X-ray bursts upon the surrounding environment.  
Comparison of simulated backgrounds with in-orbit observations for HE, ME, and LE onboard Insight-HXMT 期刊论文  OAI收割
Astrophysics and Space Science, 2020, 卷号: 365, 页码: 158
作者:  HXMT
  |  收藏  |  浏览/下载：50/0  |  提交时间：2022/02/08
Insight-HXMT  Geant4 simulation  Background observation  Astrophysics  - Instrumentation and Methods for Astrophysics  Abstract: Insight-HXMT, the first X-ray astronomical satellite in China, aims to reveal new sources in the Galaxy and to study fundamental physics of X-ray binaries from 1 to 250 keV. It has three collimated telescopes, the High Energy X-ray telescope (HE), the Medium Energy X-ray telescope (ME), and the Low Energy X-ray telescope (LE). Before the launch, in-orbit backgrounds of these three telescopes had been estimated through Geant4 simulation, in order to investigate the instrument performance and the achievement of scientific goals. In this work, these simulated backgrounds are compared with in-orbit observations. Good agreements are shown for all three telescopes. For HE, (1) the deviation of the simulated background rate after two years of operation in space is 5 % from the observation  (2) the total background spectrum and the relative abundance of the 67 keV line show long-term increases both in simulations and observations. For ME, (1) the deviation of simulated background rate is within 15 % from the observation, and (2) there are no obvious long-term increase features in the background spectra of simulations and observations. For LE, the background level given by simulations is also consistent with observations. The consistencies of these comparisons validate that the Insight-HXMT mass model, i.e., space environment components and models adopted, physics processes selected, and detector constructions built, is reasonable. However, the line features at 7.5 and 8.0 keV, which are obvious in the observed spectra of LE, are not evident in simulations. This might result from uncertainties in the LE constructions.  
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.  
In-orbit Demonstration of X-Ray Pulsar Navigation with the Insight-HXMT Satellite 期刊论文  OAI收割
The Astrophysical Journal Supplement Series, 2019, 卷号: 244, 页码: 1
作者:  HXMT
  |  收藏  |  浏览/下载：15/0  |  提交时间：2022/02/08
pulsars: general  techniques: miscellaneous  Astrophysics -  Instrumentation and Methods for Astrophysics  Abstract: In this work, we report the in-orbit demonstration of X-ray pulsar navigation with Insight-Hard X-ray Modulation Telescope (Insight-HXMT) Satellite, which was launched on 2017 June 15. The new pulsar navigation method Significance Enhancement of Pulse-profile with Orbit-dynamics is adopted to determine the orbit with observations of only one pulsar. In this test, the Crab pulsar is chosen and observed by Insight-HXMT from 2017 August 31 to September 5. Using the five-day long observation data, the orbit of Insight-HXMT is determined successfully with the three telescopes onboard: High Energy X-ray Telescope, Medium Energy X-ray Telescope, and Low Energy X-ray Telescope, respectively. By combining all the data, the position and velocity of the Insight-HXMT are pinpointed to within 10 km (3ҩ and 10 m s-1 (3ҩ, respectively.  
Temperature evolution of structural and electrical property for Sr7Mn4O15 at high temperature 期刊论文  OAI收割
JOURNAL OF ALLOYS AND COMPOUNDS, 2017, 卷号: 699, 页码: 230-234
作者:  Yang, X. M.;  Xie, Weimei;  Gu, X. M.;  Zhou, G. T.;  Lv, Kai
收藏  |  浏览/下载：30/0  |  提交时间：2017/04/06
Pd(PrSO3)(2)@SBA-15 and Pd-NPs(PrSO3)@SBA-15 hybrid materials: A highly active, reusable, and selective interface catalyst for C-X activations in air and water 期刊论文  OAI收割
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY, 2015, 卷号: 32, 页码: 218-224
作者:  Rostamnia, Sadegh;  Rahmani, Turaj;  Xin, Hongchuan
收藏  |  浏览/下载：39/0  |  提交时间：2016/01/14
进行凡纳滨对虾家系鉴定的多重微卫星鉴定体系及应用 专利  OAI收割
专利类型: 发明, 专利号: CN201310340730.1, 申请日期: 2013-12-25, 公开日期: 2013-12-25
作者:  相建海;  于洋
收藏  |  浏览/下载：38/0  |  提交时间：2014/08/04
进行凡纳滨对虾家系鉴定的多重微卫星鉴定体系  包括多重微卫星引物体系  其特征在于：使用多态性高的LvM1‑LvM15共15对微卫星引物构成两个多重微卫星引物体系  所述的两个多重微卫星引物体系如下：1）多重微卫星引物体系1的引物序列和荧光标记组合为：LvM1F:6‑FAM（羧基荧光素）‑5’‑GATGACCTGCCTTTCTCTGC‑3’LvM1R:5’‑GGGAGAGATGATGGGAAGAAG‑3’LvM2F:ROX（羧基X罗丹明）‑5’‑ATGGCACAAATAGGATCTTG‑3’LvM2R:5’‑GACTGGAAGAGCACTGATTC‑3’LvM3F:HEX(六氯荧光素)‑5’‑ATACGAAACACCCCATCCC‑3’LvM3R:5’‑GTGGTCTTACCTCGTGGCTC‑3’LvM4F:TAMRA(羧基四甲基罗丹明)‑5’‑AGCACCTAGCACTTGCTGAAC‑3’LvM4R:5’‑AGAGACTCACATCCTCATCCTC‑3’LvM5F:6‑FAM（羧基荧光素）‑5’‑CATTGAAAACGGAATCCTCG‑3’LvM5R:5’‑GATATTCCCATCAACACAGCG‑3’LvM6F:ROX（羧基X罗丹明）‑5’‑CACCAAAACGAACGAAACG‑3’LvM6R:5’‑GGATAAAAACGAATTGTATACCG‑3’LvM7F:HEX(六氯荧光素)‑5’‑GAGAGCAAATAAGAAAGGGC‑3’LvM7R:5’‑AGGATGCAAATGATAACGAG‑3’LvM8F:TAMRA(羧基四甲基罗丹明)‑5’‑GGCACACTGTTTAGTCCTCG‑3’LvM8R:5’‑CGAACAGAATGGCAGAGGAG‑3’LvM9F:6‑FAM（羧基荧光素）‑5’‑CCCGACTTGGCTTTTAGTTG‑3’LvM9R:5’‑GAGATTGCTATCCTCGGCTG‑3’LvM10F:ROX（羧基X罗丹明）‑5’‑GATCCTGCGAGTCACTTTATCTC‑3’LvM10R:5’‑TTTATTGCGTATCCCAGAAGC‑3’2）多重微卫星引物体系2的引物和荧光标记组合如下：LvM11F:6‑FAM（羧基荧光素）‑5’‑CCGCCATCATCATCAACA‑3’LvM11R:5’‑TCATTCGGGTTCGAGACTC‑3’LvM12F:ROX（羧基X罗丹明）‑5’‑GATCATTCGCCCCTCTTTTT‑3’LvM12R:5’‑ATCTACGGTTCGAGAGCAGA‑3’LvM13F:HEX(六氯荧光素)‑5’‑GGACTCACACTTCTGGTTC‑3’LvM13R:5’‑GGCTGCACCTTGTAAGTC‑3’LvM14F:TAMRA(羧基四甲基罗丹明)‑5’‑TATGCTCGTTCCCTTTGCTT‑3’LvM14R:5’‑TTGAAGGAAAAGTGTTGGGG‑3’LvM15F:6‑FAM（羧基荧光素）‑5’‑ACTAGTGGATCTGTCTATTCAT‑3’LvM15R:5’‑ATACCCACCCATGCATGTTA‑3’。  
Identification of 15d-PGJ(2) as an antagonist of farnesoid X receptor: Molecular modeling with biological evaluation 期刊论文  OAI收割
STEROIDS, 2013, 卷号: 78, 期号: 9, 页码: 813-822
作者:  Xu, Xing;  Lul, Yin;  Chen, Lili;  Chen, Jing;  Luo, Xiaomin
  |  收藏  |  浏览/下载：27/0  |  提交时间：2019/01/08