We present broadband X-ray spectral analysis of the black hole X-ray binary MAXI J1348-630,performed using five AstroSat observations.The source was in the soft spectral state for the first three observations and in t...We present broadband X-ray spectral analysis of the black hole X-ray binary MAXI J1348-630,performed using five AstroSat observations.The source was in the soft spectral state for the first three observations and in the hard state for the last two.The three soft state spectra were modeled using a relativistic thin accretion disk with reflection features and thermal Comptonization.Joint fitting of the soft state spectra constrained the spin parameter of the black hole a_(*)>0.97 and the disk inclination angle i=32.9_(-0.6)^(+4.1)degrees.The bright and faint hard states had bolometric flux a factor of~6 and~10 less than that of the soft state respectively.Their spectra were fitted using the same model except that the inner disk radius was not assumed to be at the last stable orbit.However,the estimated values do not indicate large truncation radii and the inferred accretion rate in the disk was an order of magnitude lower than that of the soft state.Along with earlier reported temporal analysis,AstroS at data provide a comprehensive picture of the evolution of the source.展开更多
在斯仑贝谢公司出版的《油田评论》1990年第2卷第2期上详细报道了该公司正在研制的MAXIS系统。MAXIS是multitask acquisition and imaging system(多重任务的采集与成象系统)的首字母缩写。MAXIS将是CSU的更新换代产品,它包括重新设计的...在斯仑贝谢公司出版的《油田评论》1990年第2卷第2期上详细报道了该公司正在研制的MAXIS系统。MAXIS是multitask acquisition and imaging system(多重任务的采集与成象系统)的首字母缩写。MAXIS将是CSU的更新换代产品,它包括重新设计的MAXIS 500地面系统、一个新的交互成象工作站以及新型井下成象仪器和高数据传输率的遥测装置。MAXIS系统将大大提高井场效率,改善测井质量,并使用户参与测井工作。本文根据上述报道编译而成。展开更多
Galactic transient black hole candidate(BHC)MAXI J1836–194 was discovered on 2011 Aug30,by MAXI/GSC and Swift/BAT.The source activity during this outburst continued for^3 months before entering into the quiescent sta...Galactic transient black hole candidate(BHC)MAXI J1836–194 was discovered on 2011 Aug30,by MAXI/GSC and Swift/BAT.The source activity during this outburst continued for^3 months before entering into the quiescent state.It again became active in March 2012 and continued for another^2 months.In this paper,3-25 keV RXTE/PCA spectra from the 2011 outburst and 0.5-10.0 keV Swift/XRT data during its 2012 outburst are analyzed with the two-component advective flow(TCAF)model based fits files in XSPEC.We calculate the X-ray contributions coming from jets/outflow using a newly developed method based on the deviation of the TCAF model normalization.We also study the correlation between observed radio and estimated jet X-ray fluxes.The correlation indices(b)are found to be 1.79 and 0.61,when the 7.45 GHz Very Large Array(VLA)radio flux is correlated with the total X-ray and jet X-ray fluxes in 3-25 keV range respectively.It has been found that the jet contributes in X-rays up to a maximum of 86%during its 2011 outburst.This makes the BHC MAXI J1836–194 strongly jet dominated during the initial rising phase.展开更多
Low mass black hole binaries are generally transient sources and spend most of their time in the quiescent state. It is believed that the inner accretion flow in the quiescent state is in the form of advection dominat...Low mass black hole binaries are generally transient sources and spend most of their time in the quiescent state. It is believed that the inner accretion flow in the quiescent state is in the form of advection dominated accretion flow and the cold outer accretion disk is truncated far away from the central black hole. During the onset of an outburst, the disk gradually extends towards the central black hole.However, the observational evidence for this general picture is indirect at best. Here we present the results of a study performed to understand the variation of the inner disk radius during the early phase of an outburst. We investigated the variation of the inner disk radius during the 2010 outburst of the black hole candidate MAXI J1659-152 using the method of simultaneous spectral fitting. We found that the inner edge of the disk is truncated at a large radius in the beginning of the outburst when the source was in the hard state. We found a systematic decrease in the inner disk radius as the outburst progressed. We also estimated an upper limit on the mass of the black hole to be 8.1 ± 2.9 M within the uncertainty of the distance and inclination angle.展开更多
We present the results obtained from detailed timing and spectral studies of a black hole candidate MAXI J1813-095 using Swift,NICER,and NuSTAR observations during its 2018 outburst.The timing behavior of the source i...We present the results obtained from detailed timing and spectral studies of a black hole candidate MAXI J1813-095 using Swift,NICER,and NuSTAR observations during its 2018 outburst.The timing behavior of the source is mainly studied by examining NICER light curves in the 0.5−10 keV range.We did not find any signature of quasi-periodic oscillations in the power density spectra of the source.We carry out spectral analysis with a combined disk blackbody&power law model,and physical two-component advective flow(TCAF)model.From the combined disk blackbody&power-law model,we extracted thermal and non-thermal fluxes,photon index and inner disk temperature.We also find evidence for weak reflection in the spectra.We have tested the physical TCAF model on a broadband spectrum from NuSTAR and Swift/XRT.The parameters like mass accretion rates,the size of Compton clouds and the shock strength are extracted.Our result affirms that the source remained in the hard state during the entire outburst which indicates a‘failed’outburst.We estimate the mass of the black hole as 7.4±1.5M⊙from the spectral study with the TCAF model.We apply the LAOR model for the Fe K line emission.From this,the spin parameter of the black hole is ascertained as a^(∗)>0.76.The inclination angle of the system is estimated to be in the range of 28°−45°from the reflection model.We find the source distance to be∼6 kpc.展开更多
The pollen abortion of Maxie A and Zhengshan97 A belong to stainless type with Ksolu-tion.The maiority of Maxie A abortive Pollenstook cireular shape and few was staining abortion
The genetic behavior of fertility restorationgenes of the cytoplasmic male sterile line Max-ie A was studied to facilitate the use ofMaweizhan male sterile cytoplasm.The F,F,and Fof Maxie A/Minhui 63 were grownin padd...The genetic behavior of fertility restorationgenes of the cytoplasmic male sterile line Max-ie A was studied to facilitate the use ofMaweizhan male sterile cytoplasm.The F,F,and Fof Maxie A/Minhui 63 were grownin paddy field,1993-1995.Meanwhile,someof the Fplants were testcrossed with themaintainer of Maxie A.The fertilities were展开更多
Bilevel programming problems are of growing interest both from theoretical and practical points of view.In this paper,we study a pessimistic bilevel programming problem in which the set of solutions of the lower level...Bilevel programming problems are of growing interest both from theoretical and practical points of view.In this paper,we study a pessimistic bilevel programming problem in which the set of solutions of the lower level problem is discrete.We first transform such a problem into a single-level optimization problem by using the maximum-entropy techniques.We then present a maximum entropy approach for solving the pessimistic bilevel programming problem.Finally,two examples illustrate the feasibility of the proposed approach.展开更多
卷积神经网络性能的快速提升是以不断堆叠的网络层数以及成倍增长的参数量和存储空间为代价,这不仅会使模型在训练过程中出现过拟合等问题,也不利于模型在资源受限的嵌入式设备上运行,因而提出模型压缩技术来解决上述问题,主要对模型压...卷积神经网络性能的快速提升是以不断堆叠的网络层数以及成倍增长的参数量和存储空间为代价,这不仅会使模型在训练过程中出现过拟合等问题,也不利于模型在资源受限的嵌入式设备上运行,因而提出模型压缩技术来解决上述问题,主要对模型压缩技术中的特征蒸馏算法进行了研究。针对特征蒸馏中利用教师网络特征图指导学生网络并不能很好地锻炼学生网络特征拟合能力的问题,提出基于特征分布蒸馏算法。该算法利用条件互信息的概念构建模型特征空间的概率分布,并引入最大平均差异(maximum mean discrepancy,MMD)设计损失函数以最小化教师网络和学生网络特征分布间的距离。在知识蒸馏的基础上利用toeplitz矩阵对学生网络进行权重共享操作,进一步节省了模型的存储空间。为验证在特征分布蒸馏算法训练下学生网络的特征拟合能力,在图像分类、目标检测和语义分割三种图像处理任务上进行了实验验证,实验表明所提算法在以上三种学习任务中的表现均优于对比算法且实现了不同网络架构间的蒸馏。展开更多
基金support from the China Scholarship Council(CSC),Grant No.2020GXZ016647IUCAA Visitors Programme+1 种基金the Centre for Research,CHRIST(Deemed to be University)financial support in the form of a Seed Money Grant(SMSS-2217)。
文摘We present broadband X-ray spectral analysis of the black hole X-ray binary MAXI J1348-630,performed using five AstroSat observations.The source was in the soft spectral state for the first three observations and in the hard state for the last two.The three soft state spectra were modeled using a relativistic thin accretion disk with reflection features and thermal Comptonization.Joint fitting of the soft state spectra constrained the spin parameter of the black hole a_(*)>0.97 and the disk inclination angle i=32.9_(-0.6)^(+4.1)degrees.The bright and faint hard states had bolometric flux a factor of~6 and~10 less than that of the soft state respectively.Their spectra were fitted using the same model except that the inner disk radius was not assumed to be at the last stable orbit.However,the estimated values do not indicate large truncation radii and the inferred accretion rate in the disk was an order of magnitude lower than that of the soft state.Along with earlier reported temporal analysis,AstroS at data provide a comprehensive picture of the evolution of the source.
基金support from DST/GITA sponsored by the India-Taiwan collaborative project fund(GITA/DST/TWN/P-76/2017)support from DST/SERB sponsored by the Extra Mural Research project(EMR/2016/003918)+1 种基金supported in part by the Higher Education Dept.of the Govt.of West Bengal,Indiasupport from the ISRO sponsored RESPOND project(ISRO/RES/2/418/17-18)fund.
文摘Galactic transient black hole candidate(BHC)MAXI J1836–194 was discovered on 2011 Aug30,by MAXI/GSC and Swift/BAT.The source activity during this outburst continued for^3 months before entering into the quiescent state.It again became active in March 2012 and continued for another^2 months.In this paper,3-25 keV RXTE/PCA spectra from the 2011 outburst and 0.5-10.0 keV Swift/XRT data during its 2012 outburst are analyzed with the two-component advective flow(TCAF)model based fits files in XSPEC.We calculate the X-ray contributions coming from jets/outflow using a newly developed method based on the deviation of the TCAF model normalization.We also study the correlation between observed radio and estimated jet X-ray fluxes.The correlation indices(b)are found to be 1.79 and 0.61,when the 7.45 GHz Very Large Array(VLA)radio flux is correlated with the total X-ray and jet X-ray fluxes in 3-25 keV range respectively.It has been found that the jet contributes in X-rays up to a maximum of 86%during its 2011 outburst.This makes the BHC MAXI J1836–194 strongly jet dominated during the initial rising phase.
文摘Low mass black hole binaries are generally transient sources and spend most of their time in the quiescent state. It is believed that the inner accretion flow in the quiescent state is in the form of advection dominated accretion flow and the cold outer accretion disk is truncated far away from the central black hole. During the onset of an outburst, the disk gradually extends towards the central black hole.However, the observational evidence for this general picture is indirect at best. Here we present the results of a study performed to understand the variation of the inner disk radius during the early phase of an outburst. We investigated the variation of the inner disk radius during the 2010 outburst of the black hole candidate MAXI J1659-152 using the method of simultaneous spectral fitting. We found that the inner edge of the disk is truncated at a large radius in the beginning of the outburst when the source was in the hard state. We found a systematic decrease in the inner disk radius as the outburst progressed. We also estimated an upper limit on the mass of the black hole to be 8.1 ± 2.9 M within the uncertainty of the distance and inclination angle.
基金This research has made use of data and/or software provided by the High Energy Astrophysics Science Archive Research Center(HEASARC)which is a service of the Astrophysics Science Division at NASA/GSFC and the High Energy Astrophysics Division of the Smithsonian Astrophysical Observatory+5 种基金This research has made use of the NuSTAR Data Analysis Software(NuSTARDAS)jointly developed by the ASI Science Data Center(ASDC,Italy)California Institute of Technology(Caltech,USA)This work has made use of XRT data supplied by the UK Swift Science Data Centre at the University of Leicester,UK.A.J.and N.K.acknowledge support from the research fellowship from Physical Research Laboratory,Ahmedabad,Indiafunded by the Department of Space,Government of India for this work.K.C.acknowledges support from the DST/INSPIRE Fellowship(IF170233)R.B.acknowledges support from the CSIR-UGC NET qualified UGC fellowship(June-2018,527223)Research by S.K.C.and D.D.is supported in part by the Higher Education Dept.of the Govt.of West Bengal,India.S.K.C.and D.D.also acknowledge partial support from ISRO sponsored RESPOND project(ISRO/RES/2/418/17-18)fund.H.-K.C.is supported by MOST of Taiwan under grants MOST/106-2923-M-007-002-MY3 and MOST/108-2112-M-007-003.D.D.acknowledges support from DST/GITA sponsored India-Taiwan collaborative project(GITA/DST/TWN/P-76/2017)fund.
文摘We present the results obtained from detailed timing and spectral studies of a black hole candidate MAXI J1813-095 using Swift,NICER,and NuSTAR observations during its 2018 outburst.The timing behavior of the source is mainly studied by examining NICER light curves in the 0.5−10 keV range.We did not find any signature of quasi-periodic oscillations in the power density spectra of the source.We carry out spectral analysis with a combined disk blackbody&power law model,and physical two-component advective flow(TCAF)model.From the combined disk blackbody&power-law model,we extracted thermal and non-thermal fluxes,photon index and inner disk temperature.We also find evidence for weak reflection in the spectra.We have tested the physical TCAF model on a broadband spectrum from NuSTAR and Swift/XRT.The parameters like mass accretion rates,the size of Compton clouds and the shock strength are extracted.Our result affirms that the source remained in the hard state during the entire outburst which indicates a‘failed’outburst.We estimate the mass of the black hole as 7.4±1.5M⊙from the spectral study with the TCAF model.We apply the LAOR model for the Fe K line emission.From this,the spin parameter of the black hole is ascertained as a^(∗)>0.76.The inclination angle of the system is estimated to be in the range of 28°−45°from the reflection model.We find the source distance to be∼6 kpc.
文摘The pollen abortion of Maxie A and Zhengshan97 A belong to stainless type with Ksolu-tion.The maiority of Maxie A abortive Pollenstook cireular shape and few was staining abortion
文摘The genetic behavior of fertility restorationgenes of the cytoplasmic male sterile line Max-ie A was studied to facilitate the use ofMaweizhan male sterile cytoplasm.The F,F,and Fof Maxie A/Minhui 63 were grownin paddy field,1993-1995.Meanwhile,someof the Fplants were testcrossed with themaintainer of Maxie A.The fertilities were
基金Supported by the National Natural Science Foundation of China(11501233)the Key Project of Anhui Province University Excellent Youth Support Plan(gxyq ZD2016102)
文摘Bilevel programming problems are of growing interest both from theoretical and practical points of view.In this paper,we study a pessimistic bilevel programming problem in which the set of solutions of the lower level problem is discrete.We first transform such a problem into a single-level optimization problem by using the maximum-entropy techniques.We then present a maximum entropy approach for solving the pessimistic bilevel programming problem.Finally,two examples illustrate the feasibility of the proposed approach.
文摘卷积神经网络性能的快速提升是以不断堆叠的网络层数以及成倍增长的参数量和存储空间为代价,这不仅会使模型在训练过程中出现过拟合等问题,也不利于模型在资源受限的嵌入式设备上运行,因而提出模型压缩技术来解决上述问题,主要对模型压缩技术中的特征蒸馏算法进行了研究。针对特征蒸馏中利用教师网络特征图指导学生网络并不能很好地锻炼学生网络特征拟合能力的问题,提出基于特征分布蒸馏算法。该算法利用条件互信息的概念构建模型特征空间的概率分布,并引入最大平均差异(maximum mean discrepancy,MMD)设计损失函数以最小化教师网络和学生网络特征分布间的距离。在知识蒸馏的基础上利用toeplitz矩阵对学生网络进行权重共享操作,进一步节省了模型的存储空间。为验证在特征分布蒸馏算法训练下学生网络的特征拟合能力,在图像分类、目标检测和语义分割三种图像处理任务上进行了实验验证,实验表明所提算法在以上三种学习任务中的表现均优于对比算法且实现了不同网络架构间的蒸馏。
