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The study of proto-magnetar winds

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Research in Astronomy and Astrophysics 2010年第3期10卷 244-252页

作者： Yan-Jun Chen ye-fei yuan Department of Physics and Electronic Science Changsha University of Science and Technology Changsha Hunan 410114 Center for Astrophysics University of Science and Technology of China Hefei 230026 China

The velocity profiles and properties of proto-magnetar winds are investigated. It is found that the corotation of wind matter with magnetic field lines significantly affects r-process nucleosynthesis and could lead to... 详细信息

关键词： stars: neutron -- stars: winds outflows -- supernovae: general -- stars magnetic fields -- nuclear reactions nucleosynthesis abundances

Constraints on black hole spins with a general relativistic accretion disk corona model

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Research in Astronomy and Astrophysics 2016年第4期16卷 15-26页

作者： Bei You Xin-Wu Cao ye-fei yuan Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical ObservatoryChinese Academy of SciencesShanghai 200030China Department of Astronomy University of Science and Technology of ChinaHefei 230026China University of Chinese Academy of Sciences Beijing 100049China

The peaks in the spectra of the accretion disks surrounding massive black holes in quasars are in the far-UV or soft X-ray band, which are usually not observed. However, in the disk corona model, soft photons from the disk are Comptonized to high energy in the hot corona, and the hard X-ray spectra （lu- minosity and spectral shape） contain information on the incident spectra from the disk. The values of black hole spin parameter a. are inferred from the spectral fitting, which are spread over a large range, ~ -0.94 to 0.998. We find that the inclination angles and mass accretion rates are well determined by the spectral fitting, but the results are sensitive to the accuracy of black hole mass estimates. No tight constraints on the black hole spins are achieved, if the uncertainties in black hole mass measurements are a factor of four, which are typical for the single-epoch reverberation mapping method. Recently, the accuracy of black hole mass measurement has been significantly improved to 0.2 - 0.4 dex with the velocity resolved reverber- ation mapping method. The black hole spin can be well constrained if the mass measurement accuracy is 50%. In the accretion disk corona scenario, a fraction of power dissipated in the disk is transported into the corona, and therefore the accretion disk is thinner than a bare disk for the same mass accretion rate, because the radiation pressure in the disk is reduced. We find that the thin disk approximation, H/R ≤0. 1, is still valid if 0.3 〈 m 〈 0.5, provided half of the dissipated power is radiated in the corona above the disk.

关键词： quasars: accretion disk -- X-ray: corona -- black hole physics -- galaxies: active

Maser Emission of Relativistic Electrons Spiralling and Drifting in Curved Magnetic Fields

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Chinese Journal of Astronomy and Astrophysics 2007年第2期7卷 304-316页

作者： Jiong Liu ye-fei yuan Xiao-Long Deng Center for Astrophysics University of Science and Technology of China Hefei 230026

Synchro-curvature radiation describes the emission from a relativistic charged particle which is moving and spiralling in a curved magnetic field. We investigate the maser emission for synchro-curvature radiation including drift of the guiding center of the radiating electron. It is shown that under some conditions the absorption coefficient can be negative, so maser can happen. These conditions are different from those needed for maser emission of curvature radiation including drift of the charged particles. We point out that our results, including the emissivity, can reduce to these of curvature radiation. Previously it was found that synchro-curvature radiation can not generate maser in vacuum, but we argue that synchrocurvature radiation including drift can generate maser even in vacuum. We discuss the possibilities of the potential applications of the synchro-curvature maser in modeling gamma ray bursts and pulsars.

关键词： masers - plasmas - radiation mechanisms non-thermal

The Effect of AGN and SNe Feedback on Star Formation,Reionization and the Near Infrared Background

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Chinese Journal of Astronomy and Astrophysics 2008年第6期8卷 631-642页

作者： Lei Wangt Ji-Rong Mao Shou-Ping Xiang ye-fei yuan Center for Astrophysics University of Science and Technology of China Hefei 230026 China Yunnan Observatory National Astronomical Observatories Chinese Academy of Sciences Kunming 650011 China

Feedback from supernovae （SNe） and from active galactic nuclei （AGN） accom- panies the history of star formation and galaxy evolution. We present an analytic model to explain how and when the SNe and AGN exert their feedback effects on the star formation and galaxy evolution processes. By using SNe and AGN kinetic feedback mechanisms based on the Lambda Cold Dark Matter （LCDM） model, we explore how these feedback mecha- nisms affect the star formation history （SFH）, the Near-Infrared Background （NIRB） flux and the cosmological reionization. We find the values of the feedback strengths, εAGN = 1.0 -0.03^＋0.5 and εSN = 0.04 -0.02^＋0.02, can provide a reasonable explanation of most of the observational resuits, and that the AGN feedback effect on star formation history is quite different from the SNe feedback at high redshifts. Our conclusions manifest quantitatively that these feedback effects decrease star formation rate density （SFRD） and the NIRB flux （in 1.4 - 4.0 μm）, and postpone the time of completion of the cosmological reionization.

关键词： cosmology theory galaxies evolution infrared general stars formation

The mass ratio distribution of MBH binaries in the hierarchical model

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Research in Astronomy and Astrophysics 2015年第6期15卷 773-784页

作者： Sheng-Nian Xu ye-fei yuan Jing-Meng Hao Ning-Yu Tang Key Laboratory for Research in Galaxies and Cosmology University of Science and Technology of China Chinese Academy of Sciences Academy of Mathematics and Systems Science Chinese Academy of Sciences

We present different mass ratio distributions of massive black hole （MBH） binaries due to different mechanisms involved in binary evolution. A binary system of MBHs forms after the merger of two galaxies, which has three stages： the dynamical friction stage, the stellar scattering or circumbinary disk stage, and the gravitational radiation stage. The second stage was once believed to be the ＂final parsec problem＂（FPP） as the binary stalled at this stage because of the depletion of stars. Now, the FPP has been shown to no longer be a problem. Here we get two different mass ratio distributions of MBH binaries under two mechanisms, stellar scattering and the cir- cumbinary disk interaction. For the circumbinary disk mechanism, we assume that the binary shrinks by interaction with a circumbinary disk and the two black holes （BHs） have different accretion rates in the simulation. We apply this simple assumption to the hierarchical coevolution model of MBHs and dark matter halos, and we find that there will be more equal-mass MBH binaries in the final coalescence for the case where the circumbinary mechanism operates. This is mainly because the secondary BH in the circumbinary disk system accretes at a higher rate than the primary one.

关键词： cosmology theory -- black hole physics -- galaxies interaction

The mini-QSO's contribution to cosmic reionization

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Research in Astronomy and Astrophysics 2010年第3期10卷 199-210页

作者： Ying-Ying Wang Lei Wang Shou-Ping Xiang Yu Wang Jing-Meng Hao ye-fei yuan Center for Astrophysics University of Science and Technology of China Hefei 230026 China Shanghai Astronomical Observatory Joint Institute for Galaxy and Cosmology （JOINGC） of SHAO and USTC Shanghai 200030 China

By employing an improved simulation of the evolution of black holes （BHs） based on the merger tree of dark matter halos, we explore the relationship between the central BH mass Mbh and velocity dispersion σ＊ at high redshift z ≥ 6 and quantify the mini-QSO＇s （with BH mass M = 200 - 105M⊙） contribution to cosmic reionization. The simulation demonstrates how seed BHs migrate onto the MBH-σ＊ relation by merging with each other and accreting gas at z ≥ 6： 1. The correlation between BHs and their host halos increases as the BHs grow; 2. The slope, i.e. Ф = dlog（Mbh）/dlog（σ＊） in the relationship, is insensitive to the redshift at z 〉 6. In agreement with previous work, we find that mini-QSOs＇ ionizing capability to the Universe lies in the range - 25% - 50% if early miniquasars have extremely high duty cycles, i.e. P（z 〉 6） - 0.9 - 1.

关键词： cosmology: theory -- galaxies: evolution

Applicationof Transferin Chinese Students' Learningon Reflexive Pronouns

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海外英语 2018年第15期 231-233页

作者：叶沅菲 Nanjing Normal University Nanjing 210000China

The thesis is designed to investigate what the Chinese reflexive transfer is and how it works on the basis of *** the analysis of binding theory, mismatches between Chinese reflexive and English reflexive would be discussed in two main aspects, namely, long-distance binding and subject orientation. To test and support the argument, more sufficient teaching data would be processed from questionnaire. At the end of the analysis, it is supposed to put forward suggestions for teaching English reflexive to Chinese students.

关键词： L2 transfer reflexive pronoun binding theory SLA

Peripheral mitochondrial DNA as a neuroinflammatory biomarker for major depressive disorder

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Neural Regeneration Research 2025年第6期20卷 1541-1554页

作者： Jinmei ye Cong Duan Jiaxin Han Jinrong Chen Ning Sun yuan Li Tifei yuan Daihui Peng Division of Mood Disorder Shanghai Mental Health CenterShanghai Jiao Tong University School of MedicineShanghaiChina Department of Psychiatry First Hospital of Shanxi Medical UniversityTaiyuanShanxi ProvinceChina Shanghai Key Laboratory of Psychotic Disorders Brain Health InstituteNational Center for Mental DisordersShanghai Mental Health CenterShanghai Jiao Tong University School of MedicineShanghaiChina Co-Innovation Center of Neuroregeneration Nantong UniversityNantongJiangsu ProvinceChina

In the pathogenesis of major depressive disorder, chronic stress-related neuroinflammation hinders favorable prognosis and antidepressant response. Mitochondrial DNA may be an inflammatory trigger, after its release from stress-induced dysfunctional central nervous system mitochondria into peripheral circulation. This evidence supports the potential use of peripheral mitochondrial DNA as a neuroinflammatory biomarker for the diagnosis and treatment of major depressive disorder. Herein, we critically review the neuroinflammation theory in major depressive disorder, providing compelling evidence that mitochondrial DNA release acts as a critical biological substrate, and that it constitutes the neuroinflammatory disease pathway. After its release, mitochondrial DNA can be carried in the exosomes and transported to extracellular spaces in the central nervous system and peripheral circulation. Detectable exosomes render encaged mitochondrial DNA relatively stable. This mitochondrial DNA in peripheral circulation can thus be directly detected in clinical practice. These characteristics illustrate the potential for mitochondrial DNA to serve as an innovative clinical biomarker and molecular treatment target for major depressive disorder. This review also highlights the future potential value of clinical applications combining mitochondrial DNA with a panel of other biomarkers, to improve diagnostic precision in major depressive disorder.

关键词： biomarker cytokine exosomes inflammasome major depressive disorder microglia mitochondrial DNA mitochondrial dysfunction neuroinflammation Toll-like receptor

肺结核患者血清中白细胞介素-2含量检测及其与呼吸功能的相关性分析

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中国防痨杂志 2015年第12期37卷 1221-1224页

作者：叶远飞赣州市第五人民医院结核科江西341000

目的研究肺结核患者血清中白细胞介素-2（interleukin-2,IL-2）含量及其与呼吸功能的相关性.方法将2011年8月至2013年8月期间我院收治的90例肺结核患者纳入研究的观察组,将同期在我院体检的90名健康者纳入研究的对照组,采用酶联免疫... 详细信息

目的研究肺结核患者血清中白细胞介素-2（interleukin-2,IL-2）含量及其与呼吸功能的相关性.方法将2011年8月至2013年8月期间我院收治的90例肺结核患者纳入研究的观察组,将同期在我院体检的90名健康者纳入研究的对照组,采用酶联免疫吸附法（enzyme-linked immunosorbent assay,ELISA）检测血清中IL-2的含量,同时评价呼吸功能指标最大呼气流速、呼气一秒率、呼吸困难评分、6 min步行距离、步行后心率及呼吸频率.采用SPSS 18.0软件包进行数据的统计和分析,计量资料采用t检验分析,以P＜0.05为差异有统计学意义.结果（1）观察组患者高于对照组血清中IL-2含量分别为（185.8±29.5） pg/ml和（45.3±6.3）pg/ml,差异有统计学意义（t=16.392、P＜0.05）.观察组最大呼气流速（54.81±7.34）ml/s、呼气一秒率（51.36±5.58）％、呼吸困难评分（3.23±0.41）分、6 min步行距离（318.46±35.23）m均低于对照组（74.23±9.26） ml/s、（57.85±6.32）％、（4.68±0.53）分、（424.27±49.35）m,差异均有统计学意义（t值分别为5.283、4.894、5.896、6.905,P值均＜0.05）;观察组步行后心率（103.31±13.95）次/min及步行后呼吸频率分别为（32.66±4.21）次/min,均高于对照组（89.48±9.59）次/min、（23.45±2.94）次/min;差异均有统计学意义（t值分别为4.985、6.475、P值均＜0.05）（2）IL-2含量与最大呼气流速、呼气一秒率、呼吸困难评分、6 min步行距离呈负相关,与步行后心率及呼吸频率呈正相关,回归系数分别为-1.768、-1.650、-2.112、-1.932、2.342、1.904,P值均＜0.05.结论肺结核患者血清中IL-2含量显著升高,且与呼吸功能密切相关,可作为判断患者呼吸功能的客观指标.

关键词：结核,肺/血液白细胞介素2 呼吸功能试验