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Timing and Spectral Analysis of the Black Hole X-Ray Binary MAXI J1803-298 with Insight-HXMT Data
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作者 Ying-Chen Xu Jin-Lu Qu +6 位作者 MMéndez Rui-Can Ma Long Ji Liang Zhang Yue Huang Qing-Cui Bu Li-Ming Song 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第6期209-224,共16页
We present a comprehensive analysis of the 2021 outburst of MAXI J1803–298 utilizing observations of the Insight-Hard X-ray Modulation Telescope(Insight-HXMT)spanning from the low hard state to the high soft state.Wi... We present a comprehensive analysis of the 2021 outburst of MAXI J1803–298 utilizing observations of the Insight-Hard X-ray Modulation Telescope(Insight-HXMT)spanning from the low hard state to the high soft state.Within the Insight-HXMT data set,compared to the previous work,we identify a more prolonged presence of typeC quasi-periodic oscillations(QPOs)with centroid frequencies ranging from~0.16 to 6.3 Hz,which present correlations with the hardness ratio and the photon index of the Comptonized component.For QPO frequencies less than~2 Hz,the QPO phase lags are hard(photons of 10–19 keV arrive later than those of 1–4 keV),while at higher frequencies,the lags become soft at and above~4 Hz.Furthermore,the spectra in all Insight-HXMT observations consist of a multi-color blackbody component and a Comptonized component,as commonly observed in classical black hole X-ray binaries.We analyze state transitions and the evolution of accretion geometry in this work.The fitted inner disk radius increases abnormally during the low hard state,hypothesized to result from the corona condensing onto the inner disk.Additionally,two significant drops in flux are observed during the soft intermediate state,maybe implying changes in the corona/jet and the disk,respectively. 展开更多
关键词 x-rays:binaries ACCRETION accretion disks stars:black holes
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Study of Type-B QPOs Observed in Black Hole X-Ray Binary Swift J1728.9-3613
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作者 Raj Kumar 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第3期1-9,共9页
We report the detection of type-B quasi-periodic oscillation(QPO)of the black hole X-ray binary Swift J1728.9-3613 observed by NICER during the 2019 outburst.A type-B QPO was observed for the first two days and it dis... We report the detection of type-B quasi-periodic oscillation(QPO)of the black hole X-ray binary Swift J1728.9-3613 observed by NICER during the 2019 outburst.A type-B QPO was observed for the first two days and it disappeared as flux increased,but again appeared at∼7.70 Hz when flux was dramatically decreased.The source was found in the soft intermediate state during these observations.We further studied the energy dependence of the QPO.We found that QPO was observed only for a higher energy range implying that the origin of QPO is possibly due to the corona emitting higher energy photons by the inverse Compton process.The variation of spectral parameters can be explained with the disk truncation model.The fractional rms was found to be monotonically increased with energy.The phase lag spectrum followed the“U-shaped”curve.The rms and phase lag spectrum are modeled and explained with the single-component Comptonization model vkompthdk. 展开更多
关键词 x-rays binaries-accretion-accretion disks-x-rays individual (Swift J1728.9-3613)
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The orbital phase resolved spectroscopy of X-ray binary 4U 1822–371 with Suzaku
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作者 Shu Niu Shu-Ping Yan +3 位作者 Shi-Jun Lei Michael A.Nowak Norbert S.Schulz Li Ji 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2016年第4期37-46,共10页
4U 1822-371 is a typical edge-on eclipsing low mass X-ray binary and the prototype of accre- tion disk coronal sources. We report on the results of a spectral analysis over the energy range 0.5-45 keV observed by Suza... 4U 1822-371 is a typical edge-on eclipsing low mass X-ray binary and the prototype of accre- tion disk coronal sources. We report on the results of a spectral analysis over the energy range 0.5-45 keV observed by Suzaku in 2006. We extract spectra from five orbital phases. The spectra can be equally well described by various previously proposed models: an optically thick model described by a partially cov- ered cutoff power law and an optically thin model described by a blackbody plus a cutoff power law. The optically thick model requires a covering fraction of about 55%, while the optically thin model requires a temperature of the central source of about 0.16 keV. The spectrum in the optically thick model also shows the previously detected cyclotron line feature at ~30 keV with the same Suzaku observation. This fea- ture confirms the presence of a strong magnetic field. The Fe Ks fluorescent line strengths as well as the detected Fe xxvI strengths are similar to previous Chandra and XMM-Newton detections in our phased spectral analysis; however, we also observe strong Fe xxvI during the eclipse, which indicates a slightly larger central corona. 展开更多
关键词 ACCRETION accretion disks -- binaries: eclipsing -- line: formation -- binaries: spectroscopic-- x-rays: binaries
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A striking confluence between theory and observations of high-mass X-ray binary pulsars
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作者 Dimitris M.Christodoulou Silas G.T.Laycock Demosthenes Kazanas 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2018年第10期117-122,共6页
We analyze the most powerful X-ray outbursts from neutron stars in eleven Magellanic high-mass X-ray binaries and three pulsating ultraluminous X-ray sources. Most of the outbursts rise to Lmax which is about the leve... We analyze the most powerful X-ray outbursts from neutron stars in eleven Magellanic high-mass X-ray binaries and three pulsating ultraluminous X-ray sources. Most of the outbursts rise to Lmax which is about the level of the Eddington luminosity, while the remaining more powerful outbursts also appear to recognize that limit when their emissions are assumed to be anisotropic and beamed toward our direction. We use the measurements of pulsar spin periods Ps and their derivatives Ps to calculate the X-ray luminosities Lp in their faintest accreting ("propeller-line") states. In five cases with unknown Ps, we use the lowest observed X-ray luminosities, which only adds to the heterogeneity of the sample. Then we calculate the ratios Lp/Lmax and we obtain an outstanding confluence of theory and observations from which we conclude that work done on both fronts is accurate and the results are trustworthy: sources known to reside on the lowest Magellanic propeller line are all located on/near that line, whereas other sources jump higher and reach higher-lying propeller lines. These jumps can be interpreted in only one way, higher-lying pulsars have stronger surface magnetic fields in agreement with previous empirical results in which Ps and Lp values were not used. 展开更多
关键词 ACCRETION accretion disks - stars magnetic fields - stars neutron - x-rays BINARIES
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Broad-band spectroscopy of the transient X-ray binary pulsar KS 1947+300 during 2013 giant outburst: Detection of pulsating soft X-ray excess component
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作者 Prahlad Epili Sachindra Naik Gaurava K.Jaisawal 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2016年第5期59-68,共10页
We present the results obtained from detailed timing and spectral studies of the Be/X-ray binary pulsar KS 1947+300 during its 2013 giant outburst. We used data from Suzaku observations of the pulsar at two epochs, i... We present the results obtained from detailed timing and spectral studies of the Be/X-ray binary pulsar KS 1947+300 during its 2013 giant outburst. We used data from Suzaku observations of the pulsar at two epochs, i.e. on 2013 October 22 (close to the peak of the outburst) and 2013 November 22. X- ray pulsations at - 18.81 s were clearly detected in the light curves obtained from both observations. Pulse periods estimated during the outburst showed that the pulsar was spinning up. The pulse profile was found to be single-peaked up to -10 keV beyond which a sharp peak followed by a dip-like feature appeared at hard X-rays. The dip-like feature has been observed up to -70 keV. The 1-110 keV broad-band spectroscopy of both observations revealed that the best-fit model was comprised of a partially absorbed Negative and Positive power law with EXponential cutoff (NPEX) continuum model along with a blackbody component for the soft X-ray excess and two Gaussian functions at 6.4 and 6.7 keV for emission lines. Both the lines were identified as emission from neutral and He-like iron atoms. To fit the spectra, we included the previously reported cyclotron absorption line at 12.2 keV. From the spin-up rate, the magnetic field of the pulsar was estimated to be -1.2 x 10^12 G and found to be comparable to that obtained from the detection of the cyclotron absorption feature. Pulse-phase resolved spectroscopy revealed the pulsating nature of the soft X-ray excess component in phase with the continuum flux. This confirms that the accretion column and/or accretion stream are the most probable regions of the soft X-ray excess emission in KS1947+300. The presence of the pulsating soft X-ray excess in phase with continuum emission may be the possible reason for not observing the dip at soft X-rays. 展开更多
关键词 pulsars: individual (KS 1947+300) -- stars: neutron -- x-rays: binaries
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Near-infrared observations of the Be/X-ray binary pulsar A0535+262
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作者 Sachindra Naik Blesson Mathew +2 位作者 D.P.K.Banerjee N.M.Ashok Rajeev R.Jaiswal 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2012年第2期177-186,共10页
We present the results obtained from extensive near-infrared (IR) spectro- scopic and photometric observations of the Be/X-ray binary A0535+262/HDE 245770 at different phases of its - 111 d orbital period. This obs... We present the results obtained from extensive near-infrared (IR) spectro- scopic and photometric observations of the Be/X-ray binary A0535+262/HDE 245770 at different phases of its - 111 d orbital period. This observation campaign is part of the monitoring program of selective Be/X-ray binary systems aimed at understanding X-ray and near-IR properties at different orbital phases, especially during the perias- tron passage of the neutron star. The near-IR observations presented here were carried out using the 1.2 m telescope at the Mt. Abu IR Observatory. Though the source was relatively faint for spectroscopic observations with the 1.2 m telescope, we monitored the source closely during the 2011 February-March giant X-ray outburst to primarily investigate whether any drastic changes in the near-IR JHK spectra took place at the periastron passage. Changes of such a striking nature were expected to be detectable in our spectra. Photometric observations of the Be star show a gradual and systematic fading in the JHK light curves since the onset of the X-ray outburst, which could suggest a mild evacuation/truncation of the circumstellar disk of the Be companion. Near-IR spectroscopy of the object shows that the JHK spectra are dominated by the emission lines of hydrogen Brackett and Paschen series and HeI lines at 1.0830, 1.7002 and 2.0585 μm. The presence of all the hydrogen emission lines in the JHK spectra, along with the absence of any significant change in the continuum of the Be companion during X-ray quiescent and X-ray outburst phases, suggests that the near- IR line emitting regions of the disk are not significantly affected during the X-ray outburst. 展开更多
关键词 infrared: stars - Be binaries - stars: individual (A0535+262) - tech-niques: spectroscopic
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Suzaku observation of Be / X-ray binary pulsar EXO 2030+375 被引量:1
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作者 Sachindra Naik Gaurava K.Jaisawal 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2015年第4期537-548,共12页
We study the timing and spectral properties of Be/X-ray binary pulsar EXO 2030+375 using a Suzaku observation taken on 2012 May 23, during a less intense Type I outburst. Pulsations were clearly detected in the X-ray... We study the timing and spectral properties of Be/X-ray binary pulsar EXO 2030+375 using a Suzaku observation taken on 2012 May 23, during a less intense Type I outburst. Pulsations were clearly detected in the X-ray light curves at a barycentric period of 41.2852 s, which suggest that the pulsar is spinning-up. The pulse profiles were found to be peculiar, e.g. unlike those obtained from the earlier Suzaku observation acquired on 2007 May 14. A single-peaked narrow profile at soft X-rays (0.5-10 keV range) changed to a double-peaked broad profile in the 12-55 keV energy range and again reverted back to a smooth single-peaked profile at hard X-rays (55-70 keV range). The 1.0-100.0 keV broadband spectrum of the pulsar was found to be well described by three continuum models described as (i) a partial covering high energy cut-off power-law model, (ii) a partially absorbed power-law with high- energy exponential rolloff and (iii) a partial covering Negative and Positive power law with EXponential (NPEX) continuum model. Unlike the earlier Suzaku observation during which several low energy emission lines were detected, a weak and narrow Iron Ka emission line at 6.4 keV was only present in the pulsar spectrum during the 2012 May outburst. Non-detection of any absorption like feature in the 1-100 keV energy range supports the claim of the absence of the cyclotron resonance scattering feature in EXO 2030+375 from the earlier Suzaku observation. Pulse-phase resolved spectroscopy revealed the presence of additional dense matter causing the absence of a second peak from the soft X-ray pulse profiles. The details of the results are described in the paper. 展开更多
关键词 pulsars: individual (EXO 2030+375) -- stars: neutron -- x-rays: stars
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AstroSat observation of the Be/X-ray binary Pulsar 3A 0726–260(4U 0728–25)
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作者 Jayashree Roy Prahlad C.Agrawal +1 位作者 Baibhav Singari Ranjeev Misra 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2020年第9期349-357,共9页
Results on timing and spectral properties of the Be/X-ray binary pulsar 3A 0726-260(4U 0728-25)are presented.The binary was observed on 2016 May 6-7 with the Large Area X-ray Proportional Counter(LAXPC)and Soft X-ray ... Results on timing and spectral properties of the Be/X-ray binary pulsar 3A 0726-260(4U 0728-25)are presented.The binary was observed on 2016 May 6-7 with the Large Area X-ray Proportional Counter(LAXPC)and Soft X-ray Telescope(SXT)instruments onboard the AstroSat satellite.During this observation,the source was in non-flaring persistent state at a flux level of^8.6±0.3×10^-11 erg cm^-2 s^-1in 0.4-20 keV.Strong X-ray pulsations with a period of 103.144±0.001 s are detected in 0.3-7 keV with the SXT and in 3-40 keV with the LAXPC.The pulse profile is energy dependent,and there is an indication that the pulse shape changes from a broad single pulse to a double pulse at higher energy.At energies above20 keV,we report the first time detection of pulsation period 103.145±0.001 s and the double peaked pulse profile from the source.The energy spectrum of the source is derived from the combined analysis of the SXT and LAXPC spectral data in 0.4-20 keV.The best spectral fit is obtained by a power law model with a photon index(1.7±0.03)with high energy spectral cut-off at 12.9±0.7 keV.A broad iron line at^6.3 keV is detected in the energy spectrum.We briefly discuss the implications of these results. 展开更多
关键词 Be/X ray binary pulsar 4U 0728–25
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基于高光谱和X-ray CT的苹果水心病无损检测方法
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作者 于心圆 王振杰 +6 位作者 尤思聪 屠康 兰维杰 彭菁 朱丽霞 陈涛 潘磊庆 《智慧农业(中英文)》 2025年第4期108-118,共11页
[目的/意义]苹果“冰糖心”又称水心病,是一种常见的果实病害,严重的水心病果会随着储藏时间的增加发生霉变,造成食品安全隐患。为实现不同等级水心病苹果快速无损检测,本研究旨在构建有效的分级与可溶性固形物(Soluble Solids Content,... [目的/意义]苹果“冰糖心”又称水心病,是一种常见的果实病害,严重的水心病果会随着储藏时间的增加发生霉变,造成食品安全隐患。为实现不同等级水心病苹果快速无损检测,本研究旨在构建有效的分级与可溶性固形物(Soluble Solids Content,SSC)预测模型。[方法]本研究选取了230个富士苹果,其中正常、轻度、中度、重度水心苹果数量分别为113、61、47和9个,分别采集了400~1000 nm范围的反射光谱和X射线计算机断层成像(X-ray Computed Tomography,X-ray CT)数据,并测定了SSC含量。[结果和讨论]SSC随水心程度加剧呈上升趋势,重度水心苹果呈现更高的光谱反射率,X-ray CT扫描成像观察到水心区域的组织体积平均密度高于健康组织,基于三维重建算法实现不同等级水心苹果内部水心组织可视化分布。基于偏最小二乘判别分析(Partial Least Squares Discriminant Analysis,PLSDA)构建的不同水心程度苹果果实分级模型建模集和测试集准确率分别为98.7%和95.9%;构建不同水心程度苹果果实SSC回归模型,校正集决定系数(Correlation Coefficient of Calibration,R_(C)^(2))为0.962,均方根误差(Root Mean Squares Error of Calibration,RMSEC)为0.264,测试集决定系数(Correlation Coefficient of Prediction,R_(P)^(2))为0.879,均方根误差(Root Mean Squares Error of Prediction,RMSEP)为0.435。[结论]该研究构建的不同水心程度苹果果实分级模型能够实现苹果不同等级水心病的预测,构建的不同水心程度苹果果实SSC回归模型能够较好地预测苹果果实的SSC,为苹果水心病无损检测和品质评估提供了有效方法。 展开更多
关键词 水心病 高光谱成像技术 x-ray CT成像技术 可溶性固形物
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Tests of Solar X-Ray Image Reconstruction:A New Index for Assessing Image Quality 被引量:1
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作者 Zhen-Tong Li Wen-Hui Yu +2 位作者 Yang Su Wei Chen Wei-Qun Gan 《Research in Astronomy and Astrophysics》 2025年第3期76-89,共14页
Indirect X-ray modulation imaging has been adopted in a number of solar missions and provided reconstructed X-ray images of solar flares that are of great scientific importance.However,the assessment of the image qual... Indirect X-ray modulation imaging has been adopted in a number of solar missions and provided reconstructed X-ray images of solar flares that are of great scientific importance.However,the assessment of the image quality of the reconstruction is still difficult,which is particularly useful for scheme design of X-ray imaging systems,testing and improvement of imaging algorithms,and scientific research of X-ray sources.Currently,there is no specified method to quantitatively evaluate the quality of X-ray image reconstruction and the point-spread function(PSF)of an X-ray imager.In this paper,we propose percentage proximity degree(PPD)by considering the imaging characteristics of X-ray image reconstruction and in particular,sidelobes and their effects on imaging quality.After testing a variety of imaging quality assessments in six aspects,we utilized the technique for order preference by similarity to ideal solution to the indices that meet the requirements.Then we develop the final quality index for X-ray image reconstruction,QuIX,which consists of the selected indices and the new PPD.QuIX performs well in a series of tests,including assessment of instrument PSF and simulation tests under different grid configurations,as well as imaging tests with RHESSI data.It is also a useful tool for testing of imaging algorithms,and determination of imaging parameters for both RHESSI and ASO-S/Hard X-ray Imager,such as field of view,beam width factor,and detector selection. 展开更多
关键词 SUN flares-Sun x-rays gamma-rays-techniques image processing
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Tests of Solar X-Ray Image Reconstruction:Study of X-Ray Imaging Algorithms and Reconstruction Parameters 被引量:1
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作者 Wenhui Yu Yang Su +2 位作者 Zhentong Li Wei Chen Weiqun Gan 《Research in Astronomy and Astrophysics》 2025年第3期90-110,共21页
Imaging observations of solar X-ray bursts can reveal details of the energy release process and particle acceleration in flares.Most hard X-ray imagers make use of the modulation-based Fourier transform imaging method... Imaging observations of solar X-ray bursts can reveal details of the energy release process and particle acceleration in flares.Most hard X-ray imagers make use of the modulation-based Fourier transform imaging method,an indirect imaging technique that requires algorithms to reconstruct and optimize images.During the last decade,a variety of algorithms have been developed and improved.However,it is difficult to quantitatively evaluate the image quality of different solutions without a true,reference image of observation.How to choose the values of imaging parameters for these algorithms to get the best performance is also an open question.In this study,we present a detailed test of the characteristics of these algorithms,imaging dynamic range and a crucial parameter for the CLEAN method,clean beam width factor(CBWF).We first used SDO/AIA EUV images to compute DEM maps and calculate thermal X-ray maps.Then these realistic sources and several types of simulated sources are used as the ground truth in the imaging simulations for both RHESSI and ASO-S/HXI.The different solutions are evaluated quantitatively by a number of means.The overall results suggest that EM,PIXON,and CLEAN are exceptional methods for sidelobe elimination,producing images with clear source details.Although MEM_GE,MEM_NJIT,VIS_WV and VIS_CS possess fast imaging processes and generate good images,they too possess associated imperfections unique to each method.The two forward fit algorithms,VF and FF,perform differently,and VF appears to be more robust and useful.We also demonstrated the imaging capability of HXI and available HXI algorithms.Furthermore,the effect of CBWF on image quality was investigated,and the optimal settings for both RHESSI and HXI were proposed. 展开更多
关键词 techniques image processing-Sun flares-Sun x-rays gamma rays
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Role of post-operative X-rays in distal-radius fractures among pediatric patients 被引量:1
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作者 Ammar K Alomran Bandar A Alzahrani +4 位作者 Dana S Alamoud Layan S Alsultan Meshail M AlSaud Raneem G Althobaiti Badriah S Alruwaili 《World Journal of Orthopedics》 2025年第5期51-60,共10页
BACKGROUND In pediatric age group patients(<18 years old)treated operatively for distal radius/both bone fractures extending imaging beyond the initial postoperative period-particularly in uncomplicated cases-appea... BACKGROUND In pediatric age group patients(<18 years old)treated operatively for distal radius/both bone fractures extending imaging beyond the initial postoperative period-particularly in uncomplicated cases-appears to provide limited additional benefit.AIM To determine the necessary number of follow-up X-rays to use resources efficiently.METHODS Participants included in this study are pediatric age group patients who were treated operatively for distal radius/both bone fractures and were identified from a prospected collected data from the operating room database between the years 2009 and 2017.The data in the study included patients who had distal radius fractures and underwent fixation surgery(n=88).RESULTS When assessing the difference in the odds of conducting 1 or less X-ray compared to 2 or more X-rays in regard to the type of fixation,the only significant difference is the closed reduction fixation method.Patients who underwent closed reduction method procedure have significantly lower odds of having 2 more X-rays compared to those who didn’t have closed reduction method.Open reduction,internal fixation,and other fixation methods(close reduction and internal fixation,debridement,or epiphysiodesis)have higher odds of having two or more X-rays compared to patients who did not receive these methods;however,these odds are not statistically significant.CONCLUSION The findings of this study reveal notable absence of a statistically significant association between the frequency of postoperative X-rays and the outcome of children with distal radius fractures. 展开更多
关键词 x-ray Distal radius fractures PEDIATRICS ORTHOPEDIC FRACTURES
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Diagnostics of temperature and blue-shifted velocity using soft X-ray spectra from the Macao Science Satellite-1 被引量:2
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作者 JianPing Li Xu Yang +6 位作者 Dong Li JinHua Shen Lei Yang Ya Wang LianSheng Li YongQiang Shi HaiSheng Ji 《Earth and Planetary Physics》 2025年第3期740-751,共12页
Using the new soft X-ray data from the Macao Science Satellite-1,we studied a solar flare that occurred on 22 June 2023.We found that the centroids of the Ca(around 3.9 keV)and Fe(around 6.7 keV)line features exhibit ... Using the new soft X-ray data from the Macao Science Satellite-1,we studied a solar flare that occurred on 22 June 2023.We found that the centroids of the Ca(around 3.9 keV)and Fe(around 6.7 keV)line features exhibit a rapid shift toward higher energy channels during the flare's rising phase,followed by a gradual decrease during the decay phase.Through precise energy calibration,the centroids are determined with high accuracy.Temperature and velocity are then self-consistently derived by comparing the centroids with those calculated from the synthesized line features using the latest CHIANTI atomic database(ver.10.1).The calculated maximum velocity reaches up to 710±60 km s-1,which significantly exceeds the previously reported values.Our results suggest that the entire shift of soft X-ray lines may occur during the process of chromospheric evaporation. 展开更多
关键词 Macao Science Satellite-1 solar flares soft x-ray lines chromospheric evaporation
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Investigation of bubbles escape behavior from low basicity mold flux for high-Mn high-Al steels using 3D X-ray microscope
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作者 Qiang Liu Xiang Li +3 位作者 Shen Du Ming Gao Yanbin Yin Jiongming Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 2025年第1期102-110,共9页
During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a rest... During the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the mold.In which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid slag.In contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive information.Therefore,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding times.The results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles increases.In addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually decreases.In one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the large.These findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels. 展开更多
关键词 mold flux low basicity BUBBLES three-dimensional x-ray microscope VISCOSITY
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CMOS direct conversion X-ray detector coupled with fluorinated liquid 被引量:1
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作者 Shi-Hua Liu Chao-Song Gao +5 位作者 Xin Zhang Xiang-Ming Sun Meng Wu Zhi-Hui Han Tong Wan Yong-Shuai Ge 《Nuclear Science and Techniques》 2025年第1期59-68,共10页
X-ray detectors show potential applications in medical imaging,materials science,and nuclear energy.To achieve high detection efficiency and spatial resolution,many conventional semiconductor materials,such as amorpho... X-ray detectors show potential applications in medical imaging,materials science,and nuclear energy.To achieve high detection efficiency and spatial resolution,many conventional semiconductor materials,such as amorphous selenium,cadmium telluride zinc,and perovskites,have been utilized in direct conversion X-ray detectors.However,these semiconductor materials are susceptible to temperature-induced performance degradation,crystallization,delamination,uneven lattice growth,radiation damage,and high dark current.This study explores a new approach by coupling an FC40 electronic fluorinated liquid with a specialized high-resolution and high-readout-speed complementary metal-oxide-semiconductor(CMOS)pixel array,specifically the Topmetal II−chip,to fabricate a direct conversion X-ray detector.The fluorinated liquid FC40(molecular formula:C_(21)F_(48)N_(2))is an electronic medium that is minimally affected by temperature and displays no issues with uniform conductivity.It exhibits a low dark current and minimal radiation damage and enables customizable thickness in X-ray absorption.This addresses the limitations inherent in conventional semiconductor-based detectors.In this study,simple X-ray detector imaging tests were conducted,demonstrating the excellent coupling capability between FC40 electronic fluorinated liquid and CMOS chips by the X-ray detector.A spatial resolution of 4.0 lp/mm was measured using a striped line par card,and a relatively clear image of a cockroach was displayed in the digital radiography imaging results.Preliminary test results indicated the feasibility of fabricating an X-ray detector by combining FC40 electronic fluorinated liquid and CMOS chips.Owing to the absence of issues related to chip-material coupling,a high spatial resolution could be achieved by reducing the chip pixel size.This method presents a new avenue for studies on novel liquid-based direct conversion X-ray detectors. 展开更多
关键词 FC40 electronic fluorinated liquid CMOS pixel chip x-ray detector Spatial resolution
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Experimental Observing Damage Evolution in Cement Pastes Exposed to External Sulfate Attack by in situ X-ray Computed Tomography
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作者 WU Min CAO Kailei +4 位作者 XIAO Weirong YU Zetai CAO Jierong DING Qingjun LI Jinhui 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2025年第1期164-170,共7页
The paper presents experimental investigation results of crack pattern change in cement pastes caused by external sulfate attack(ESA).To visualize the formation and development of cracks in cement pastes under ESA,an ... The paper presents experimental investigation results of crack pattern change in cement pastes caused by external sulfate attack(ESA).To visualize the formation and development of cracks in cement pastes under ESA,an X-ray computed tomography(X-ray CT)was used,i e,the tomography system of Zeiss Xradia 510 versa.The results indicate that X-CT can monitor the development process and distribution characteristics of the internal cracks of cement pastes under ESA with attack time.In addition,the C3A content in the cement significantly affects the damage mode of cement paste specimens during sulfate erosion.The damage of ordinary Portland cement(OPC)pastes subjected to sulfate attack with high C3A content are severe,while the damage of sulfate resistant Portland cement(SRPC)pastes is much smaller than that of OPC pastes.Furthermore,a quadratic function describes the correlation between the crack volume fraction and development depth for two cement pastes immermed in sulfate solution. 展开更多
关键词 CONCRETE external sulfate attack damage evolution situ x-ray computed tomography
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Synergistic properties of the binary mixed system of natural green surfactants:Camellia oleifera saponin and sodium cocoyl glycinate
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作者 Yawen Li Weixin Li +3 位作者 Fenglun Zhang Shihong Ma Jianxin Jiang Liwei Zhu 《日用化学工业(中英文)》 北大核心 2025年第7期831-843,共13页
Sodium cocoyl glycinate(SCG),an environmentally friendly anionic amino acid surfactant,is widely used in daily chemical products as an upgraded alternative to traditional surfactants.In this study,crude Camellia oleif... Sodium cocoyl glycinate(SCG),an environmentally friendly anionic amino acid surfactant,is widely used in daily chemical products as an upgraded alternative to traditional surfactants.In this study,crude Camellia oleifera saponin(COS)was purified using AB-8 macroporous adsorption resin,and its composition and structure were analyzed.The effects of different mole fractions of COS(αCOS)on surface tension(γ),oil-water interfacial tension(IFT),emulsification,and foam properties of COS-SCG binary mixed systems were investigated in mixtures of SCG with purified COS.The stability ofγand foamability under diverse environmental conditions were also discussed.The results indicated that the COS-SCG system exhibited remarkable surface-active synergism.The minimum critical micelle concentration(cmc)of the mixed system was lower than that of SCG,and adding a small mole fraction of COS(1%-2%)induced a synergistic reduction ofγ.Specifically,the cmc andγwere 2.50×10-4 mol/L and 23.1 mN/m forαCOS=1%,respectively.The system exhibited exceptional IFT reduction capacity,achieving a minimum value of 1.42 mN/m atαCOS=10%.The mixed system reached a foaming volume(atαCOS=50%)and foam stability(atαCOS=75%)were 51.0 mL and 97.37%,respectively.Microscopic analysis further confirmed these outstanding foam properties.Moreover,the COS-SCG system displayed reducedγwith enhanced foaming volume under elevated temperatures(35-75℃)and salinity(0-20 g/L).However,acidic conditions and hard water compromised bothγstability and foamability. 展开更多
关键词 SAPONIN sodium cocoyl glycinate binary mixed system synergism interfacial tension foam properties
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Impact factor analysis of less developed farmers'livelihood strategies based on the binary Logit model
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作者 HE Li-Long TAN Hao-Wen +1 位作者 GUO Jin-Ting XIA Ting-Fu 《四川大学学报(自然科学版)》 北大核心 2025年第5期1265-1280,共16页
In this paper,based on the structure-behavior coupling paradigm,we propose the concept of deviation of central town to describe the geography-market distance between farmers and the central regional town.Using the sur... In this paper,based on the structure-behavior coupling paradigm,we propose the concept of deviation of central town to describe the geography-market distance between farmers and the central regional town.Using the survey data from farmers in a poverty-stricken village in Western China,the impact of deviation of central town on farmers'livelihood strategies is analyzed.The results indicate that farmers exhibit spatial heterogeneity in their livelihood strategies.Those with low deviation show a strong inclination towards working in urban areas,while those with high deviation tend to integrate into rural industries.The deviation of central town influences farmers'livelihood strategies through the information effect,which is also affected by the level of rural infrastructure and public services,labor force structure and assistance policies.The obtained results are expected to provide guidance for promoting the integration of farmers into the urban-rural economic cycle based on sustainable livelihoods and connecting poverty alleviation with rural revitalization. 展开更多
关键词 Deviation of central town Livelihood strategy binary Logit model
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耐张线夹X-ray无损探伤机器人设计及应用
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作者 姜传霏 尚鑫 +3 位作者 张欣伟 黄志建 莫剑波 陈翠珠 《机床与液压》 北大核心 2025年第17期85-91,共7页
为提高高压输电线路耐张线夹无损探伤作业的效率和安全性,增加电力系统的稳定性,针对带电作业的电磁环境进行分析,自主设计X-ray无损探伤机器人。基于功能模块分解实现自上线机构、线路行走机构、X光检测机械臂及电磁兼容系统的设计,开... 为提高高压输电线路耐张线夹无损探伤作业的效率和安全性,增加电力系统的稳定性,针对带电作业的电磁环境进行分析,自主设计X-ray无损探伤机器人。基于功能模块分解实现自上线机构、线路行走机构、X光检测机械臂及电磁兼容系统的设计,开展核心零部件和等电位过程的电磁仿真分析,初步完成探伤机器人样机研制并进行220 kV带电作业实验。开发的无损探伤机器人具有轻量化设计、结构紧凑、操控简单、精准高效以及位姿灵活等特点,可实现带电线路一键自动上下线、快速跨越障碍物、保持通信流畅、实时成像等功能,在高压输电线路无损探伤作业领域具有广阔的应用前景。 展开更多
关键词 机器人 耐张线夹 x-ray无损探伤
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Transcending Binary Opposition: Exploring the Path to Harmonious Coexistence of Humanity From a Philosophical Perspective
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作者 CUI Weicheng 《Philosophy Study》 2025年第2期49-60,共12页
This paper analyzes binary opposition thinking,dominant in Western societies since ancient Greece,its prevalence in philosophy,international relations,etc.While it influenced science and technology,it also caused conf... This paper analyzes binary opposition thinking,dominant in Western societies since ancient Greece,its prevalence in philosophy,international relations,etc.While it influenced science and technology,it also caused conflicts,hindering the sustainable development of humanity.The paper explores the“binary co-existence”philosophy from Eastern thought.It explains its basis,applications,and significance in overcoming global social issues currently encountered.This philosophy emphasizes mutual dependence of opposites,offering solutions to global challenges.The paper stresses the urgency of shifting from binary opposition to binary co-existence,crucial for resolving conflicts and promoting sustainable development.It discusses ways like education and media to achieve this for global harmony. 展开更多
关键词 binary opposition binary co-existence thinking paradigm global challenges sustainable development TRANSFORMATION
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