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Light Simplified Millet Production Technique Adopting Film Mulching and Hole Sowing
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作者 李顺国 刘猛 +6 位作者 宋世佳 程汝宏 赵宇 任晓利 刘斐 南春梅 夏雪岩 《Agricultural Science & Technology》 CAS 2016年第4期887-889,905,共4页
In order to solve the problem that dry-land foxtail millet production completely relies on rainwater with low instable yield and tedious cultivation, Millet Research Institute of Hebei Academy of Agriculture and Fores... In order to solve the problem that dry-land foxtail millet production completely relies on rainwater with low instable yield and tedious cultivation, Millet Research Institute of Hebei Academy of Agriculture and Forestry Sciences integrated a light simplified production technique integrating film mulching, hole sowing and fertilization with mechanized production, forming the light simplified foxtail millet production technique adopting film mulching and hole sowing. This study introduced the light simplified foxtail millet production technique adopting film mulching and hole sowing, including main links such as preparation before sowing, sowing, attached agricultural machines, field management, harvest and residual film recovery. 展开更多
关键词 Foxtail millet Integrated film mulching hole sowing and fertilization SIMPLIFICATION
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Solvents incubatedπ-πstacking in hole transport layer for perovskite-silicon 2-terminal tandem solar cells with 27.21%efficiency
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作者 Qiaoyan Ma Jufeng Qiu +10 位作者 Yuzhao Yang Fei Tang Yilin Zeng Nanxi Ma Bohao Yu Feiping Lu Chong Liu Andreas Lambertz Weiyuan Duan Kaining Ding Yaohua Mai 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第7期25-30,I0002,共7页
Room temperature sputtered inorganic nickel oxide(NiO_(x))is one of the most promising hole transport layers(HTL)for perovskite-sillion 2-terminal tandem solar cells with the aid of ultrathin and compact organic layer... Room temperature sputtered inorganic nickel oxide(NiO_(x))is one of the most promising hole transport layers(HTL)for perovskite-sillion 2-terminal tandem solar cells with the aid of ultrathin and compact organic layers to passivate the surface defects.In this study,the aromatic solvent with different substituent groups was used to regulate the conformation of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)am ine](PTAA)layer.As a result,the single-junction perovskite solar cell(PSC)gained a power conversion efficiency(PCE)of 20.63%,contributing to a 27.21%efficiency for monolithic perovskite/silicon(double-side polished)2-terminal tandem solar cell,by applying the alkyl aromatic solvent to enhance theπ-πstacking of PTAA molecular chains.The tandem solar cell can maintain 95%initial efficiency after aging over 1000 h.This study provides a universal approach for improving the photovoltaic performance of NiO_(x)/polymer-based perovskite/silicon tandem solar cells and other single junction inverted PSCs. 展开更多
关键词 Tandem solar cells Low temperature deposition hole transporting property π-πstacking Alkyl aromatic solvent
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The parameters of binary black hole system in PKS 1510-089 被引量:3
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作者 李娟 樊军辉 袁聿海 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第3期876-880,共5页
Observations of PKS 1510-089 indicate the existence of a deep flux minimum with a timescale of -35 min and an interval of about 336 ± 14 d. A binary black hole system is proposed to be at the nucleus of this obje... Observations of PKS 1510-089 indicate the existence of a deep flux minimum with a timescale of -35 min and an interval of about 336 ± 14 d. A binary black hole system is proposed to be at the nucleus of this object. The secondary black hole orbits around the primary black hole. The minimum is caused by the periodic eclipse of the primary black hole by the secondary black hole. Based on the observations of PKS 1510-089, we estimate the parameters of the binary black hole system. The masses for the primary and secondary black holes are 1.37 × 10^9M⊙(M⊙ is the solar mass) and 1.37 × 10^7M⊙, and the major axis for this pair being about 0.1 parsec(pc). 展开更多
关键词 active galaxies black hole individual (PKS1510-089)
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Constraints on individual supermassive binary black holes using observations of PSR J1909-3744 被引量:1
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作者 Yi Feng Di Li +1 位作者 Yan-Rong Li Jian-Min Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第12期257-268,共12页
We perform a search for gravitational waves(GWs) from several supermassive binary black hole(SMBBH) candidates(NGC 5548, Mrk 231, OJ 287, PG 1302–102, NGC 4151, Ark 120 and 3C 66B) in long-term timing observations of... We perform a search for gravitational waves(GWs) from several supermassive binary black hole(SMBBH) candidates(NGC 5548, Mrk 231, OJ 287, PG 1302–102, NGC 4151, Ark 120 and 3C 66B) in long-term timing observations of the pulsar PSR J1909-3744 obtained using the Parkes radio telescope.No statistically significant signals were found. We constrain the chirp masses of those SMBBH candidates and find the chirp mass of NGC 5548 and 3C 66B to be less than 2.4 × 10^9 M⊙ and 2.5 × 10^9 M⊙(with 95% confidence), respectively. Our upper limits remain a factor of 3 to 370 above the likely chirp masses for these candidates as estimated from other approaches. The observations processed here provide upper limits on the GW strain amplitude that improve upon the results from the first Parkes Pulsar Timing Array data release by a factor of 2 to 7. We investigate how information about the orbital parameters can help to improve the search sensitivity for individual SMBBH systems. Finally, we show that these limits are insensitive to uncertainties in the Solar System ephemeris model. 展开更多
关键词 black hole physics gravitational waves pulsars:general pulsars:individual(PSR J1909-3744)
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Gamma-ray Bursts: a Probe of Black Holes
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作者 Wei Wang and Yong-Heng Zhao National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2001年第6期487-493,共7页
There is strong evidence for the existence of black holes (BHs) in some X-ray binaries and in most galactic nuclei based on different types of measurement, but black holes have not been definitely identified for the l... There is strong evidence for the existence of black holes (BHs) in some X-ray binaries and in most galactic nuclei based on different types of measurement, but black holes have not been definitely identified for the lack of very firm observational evidence up to now. Because direct evidence for BHs should come from determination of strong gravitational redshift, we expect an object can fall into the region near the BH horizon where radiation can be detected. Therefore the object must be a compact star such as a neutron star (NS), and intense astrophysical processes will release highly energetic radiation that is transient and fast-varying. These characteristics may point to the observed gamma-ray bursts (GRBs). Recent observations of iron lines suggest that afterglows of GRBs show properties similar to those observed in active galactic nuclei (AGNs), implying that the GRBs may originate from intense events related to black holes. A model for GRBs and after-glows is proposed here to obtain the range of gravitational redshifts (zg) of GRBs with known cosmological redshifts. Here, we provide a new method that, with a search for high-energy emission lines (X- or -γ-rays) in GRBs, one can determine the gravitational redshift. We expect zg to be 0.5 or even larger, so we can rule out the possibility of other compact objects such as NSs, and identify the central progenitors of GRBs as black holes. 展开更多
关键词 black hole physics - accretion accretion disks - gamma rays: burst
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Water and nitrogen transport characteristics of single-line interference infiltration under film hole irrigation with muddy water and fertilizer
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作者 JIANG Ruirui FEI Liangjun KANG Shouxuan 《排灌机械工程学报》 CSCD 北大核心 2022年第5期496-503,共8页
Based on the experimental data,this study investigated the effect of sand content of muddy water on water and nitrogen transport characteristics of the single-line interference infiltration under film hole irrigation ... Based on the experimental data,this study investigated the effect of sand content of muddy water on water and nitrogen transport characteristics of the single-line interference infiltration under film hole irrigation with muddy water and fertilizer.The relationship between the single-line interference infiltration parameters,the sand content,the wetting front movement distances,and the sand content were all established.The model of the cumulative infiltration volume of per unit film pore area,the vertical and horizontal wetting front movement distance of the free surface,and the wetting front movement distance of the interference center with sand content and infiltration time were proposed.Reveal the law of the change of soil water content and the distribution of NO_(3)^(-)-N content based on different muddy water sand content.The results indicate that at the same infiltration time,as the muddy water sand content increases,the cumulative infiltration volume per unit pore area decreases.The infiltration index of the free infiltration and the single-line interference vary little when the sand content increases,mainly are around 0.64 and 0.58.The relationship between infiltration parameters a,b and the sand content is linear function.At the same location,the more the sand content,the smaller the wetting front movement distance in free surface and the single-line interference surface,the less the NO_(3)^(-)-N content. 展开更多
关键词 film hole irrigation single-line interference infiltration muddy water FERTILIZER sand content NO_(3)^(-)-N content
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Revisiting the Evidence for an Intermediate-mass Black Hole in the Center of NGC 6624 with Simulations
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作者 Li-Chun Wang Yi Xie 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2022年第11期78-83,共6页
The acceleration of LMXB 4U 1820-30 derived from its orbital-period derivative P_(b)was supposed to be the evidence for an Intermediate-mass black hole(IMBH)in the Galactic globular cluster(GC)NGC 6624.However,we find... The acceleration of LMXB 4U 1820-30 derived from its orbital-period derivative P_(b)was supposed to be the evidence for an Intermediate-mass black hole(IMBH)in the Galactic globular cluster(GC)NGC 6624.However,we find that the anomalous P_(b)is mainly due to the gravitational wave emission,rather than the acceleration in cluster potential.Using the standard structure models of GCs,we simulate acceleration distributions for pulsars in the central region of the cluster.By fitting the acceleration of J1823-3021 A with the simulated distribution profiles(maximum values),it is suggested that an IMBH with mass M■950_(-350)^(+550)M_(⊙) may reside in the cluster center.We further show that the second period derivative P of J1823-3021 A is probably due to the gravitational perturbation of a nearby star. 展开更多
关键词 (stars:)pulsars:individual(J1823-3021A) (Galaxy:)globular clusters:individual(NGC 6624) stars:black holes
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A model of low-frequency quasi-periodic oscillations in black hole X-ray binaries
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作者 Zhi-Yun Wang Chang-Yin Huang +1 位作者 Ding-Xiong Wang Jiu-Zhou Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2012年第6期661-670,共10页
A model of low-frequency quasi-periodic oscillations (LFQPOs) of black hole X-ray binaries (BHXBs) is proposed based on the perturbed magnetohydrody- namic equations of an accretion disk. It turns out that the LFQ... A model of low-frequency quasi-periodic oscillations (LFQPOs) of black hole X-ray binaries (BHXBs) is proposed based on the perturbed magnetohydrody- namic equations of an accretion disk. It turns out that the LFQPO frequencies of some BHXBs can be fitted by the frequencies of the toroidal Alfv6n wave oscillation cor- responding to the maximal radiation flux. In addition, the positive correlation of the LFQPO frequencies with the radiation flux from an accretion disk is well interpreted. 展开更多
关键词 ACCRETION accretion disks -- black hole physics -- magnetic fields --stars: individual (XTE J1550-564 GRO J1655--40)
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Jet-dominated quiescent state in black hole X-ray binaries: the cases of A0620–00 and XTE J1118+480
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作者 Qi-Xiang Yang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2016年第4期79-86,共8页
The radiative mechanism of black hole X-ray transients (BHXTs) in their quiescent states (defined as the 2-10 keV X-ray luminosity ≤ 10^34 erg s-1) remains unclear. In this work, we investigate the quasi-simultan... The radiative mechanism of black hole X-ray transients (BHXTs) in their quiescent states (defined as the 2-10 keV X-ray luminosity ≤ 10^34 erg s-1) remains unclear. In this work, we investigate the quasi-simultaneous quiescent state spectrum (including radio, infrared, optical, ultraviolet and X-ray) of two BHXTs, A0620-00 and XTE J1118+480. We find that these two sources can be well described by a coupled accretion - jet model. More specifically, most of the emission (radio up to infrared, and the X-ray waveband) comes from the collimated relativistic jet. Emission from hot accretion flow is totally insignificant, and it can only be observed in mid-infrared (the synchrotron peak). Emission from the outer cold disk is only evident in the UV band. These results are consistent with our previous investigation on the quiescent state of V404 Cyg and confirm that the quiescent state is jet-dominated. 展开更多
关键词 ACCRETION accretion disks -- black hole physics -- X-rays: binaries -- stars: jets -- stars:individual (A0620-00 XTE J1118+480)
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Broadband Spectral Properties of MAXI J1348-630 using AstroSat Observations
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作者 Gitika Mall Jithesh Vadakkumthani Ranjeev Misra 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2023年第1期161-170,共10页
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
关键词 black hole physics-X-rays binaries-accretion-accretion disks-X-rays individual(MAXI J1348-630)
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A magnetic reconnection model for quasi-periodic oscillations in black hole systems
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作者 Chang-Yin Huang Ding-Xiong Wang +1 位作者 Jiu-Zhou Wang Zhi-Yun Wang 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2013年第6期705-718,共14页
The quasi-periodic oscillations (QPOs) in black hole (BH) systems with different scales are interpreted based on the magnetic reconnection of large-scale mag- netic fields generated by toroidal electric currents f... The quasi-periodic oscillations (QPOs) in black hole (BH) systems with different scales are interpreted based on the magnetic reconnection of large-scale mag- netic fields generated by toroidal electric currents flowing in the inner region of the accretion disk, where the current density is assumed to be proportional to the mass density of the accreting plasma. The magnetic connection (MC) is taken into account in resolving dynamic equations describing the accretion disk, in which the MC be- tween the inner and outer disk regions, between the plunging region and the disk, and between the BH horizon and the disk are involved. It turns out that a single QPO frequency associated with several BH systems with different scales can be fitted by in- voking the magnetic reconnection due to the MC between the inner and outer regions of the disk, including the BH binaries XTE J1859+226, XTE J1650-500 and GRS 1915+105 and the massive BHs in NGC 5408 X-1 and RE J1034+396. In addition, the X-ray spectra corresponding to the QPOs for these sources are fitted based on the typical disk-corona model. 展开更多
关键词 accretion accretion disks -- black hole physics -- magnetic fields --stars individual (XTE J1859+226 XTE J1650-500 GRS 1915+105) -- galaxies:individual (NGC 5408 RE J1034+396)
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鸭嘴式谷子穴播排种器设计与试验 被引量:1
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作者 刘华钰 衣淑娟 +2 位作者 陈涛 陶桂香 毛欣 《农机化研究》 北大核心 2024年第10期111-119,共9页
针对现有谷子排种器条播时重播严重的问题,结合农艺要求,设计了一种鸭嘴式谷子穴播排种器,并分析了排种器的工作过程,确定了排种器与鸭嘴式扎穴器的组合以及排种器转速、取种管直径、取种管角度。采用响应面优化试验,分析了排种器转速... 针对现有谷子排种器条播时重播严重的问题,结合农艺要求,设计了一种鸭嘴式谷子穴播排种器,并分析了排种器的工作过程,确定了排种器与鸭嘴式扎穴器的组合以及排种器转速、取种管直径、取种管角度。采用响应面优化试验,分析了排种器转速、取种管直径、取种管角度对穴粒数合格率、漏播率及重播率的影响,结果表明:在取种管角度为55°、取种管直径为8.5 mm、排种器转速为60r/min时,穴粒数合格率为96.70%,漏播率为1.74%,重播率为1.56%,排种性能较优。 展开更多
关键词 谷子 穴播排种器 鸭嘴式机构
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面向播种过程离散元仿真的玉米颗粒建模方法
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作者 陈泽仁 刘正彬 +2 位作者 关威 郭建波 薛朵梅 《农业工程学报》 EI CAS CSCD 北大核心 2024年第14期14-22,共9页
为实现基于离散元法的玉米播种过程数字化重现,改善播种机械的性能,需要构建相应的玉米颗粒群体模型。该研究对东北地区常见的玉米品种的颗粒形状、尺寸分布进行统计分析,提出了一种通用的玉米颗粒形状分类方法;在此基础上,基于球填充... 为实现基于离散元法的玉米播种过程数字化重现,改善播种机械的性能,需要构建相应的玉米颗粒群体模型。该研究对东北地区常见的玉米品种的颗粒形状、尺寸分布进行统计分析,提出了一种通用的玉米颗粒形状分类方法;在此基础上,基于球填充构建了相应的玉米颗粒群体离散元法建模方法,并以吉平1和平安11两个品种玉米为研究对象,通过堆积试验和筛分试验对填充球数目进行了优化。仿真结果表明,当马齿形、球锥形和类球形玉米颗粒模型的填充球数目分别为10~14、18和1时,玉米颗粒离散元法模型群体特性与实际玉米颗粒群体特性相一致,初步证明了所提玉米颗粒群体建模方法的有效性;最后,基于所建立的玉米颗粒群体模型进行了内窝孔排种器排种过程仿真,对其排种轮转速进行了优化,仿真优化结果与试验结果一致,进一步验证了本文所提出的玉米颗粒群体建模方法的有效性。研究结果可为播种机械数字化设计提供一定参考。 展开更多
关键词 玉米 离散元法 播种 群体建模 内窝孔排种器
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不同育苗孔穴及播种时间对烟株生长发育和质量影响
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作者 尹冬 黄旭民 +2 位作者 韩方仪 焦绍赫 张志高 《农业技术与装备》 2024年第1期167-169,172,共4页
为探究不同育苗孔穴和播种时间对烟株大田生长发育和质量的影响,筛选出合适的育苗孔穴数并确定合理的播种时间,2023年在乐安县湖溪乡进行了72孔育苗与128孔育苗对比试验,并对大田期烟株物质积累及质量进行了测定。得出如下结果:一是在... 为探究不同育苗孔穴和播种时间对烟株大田生长发育和质量的影响,筛选出合适的育苗孔穴数并确定合理的播种时间,2023年在乐安县湖溪乡进行了72孔育苗与128孔育苗对比试验,并对大田期烟株物质积累及质量进行了测定。得出如下结果:一是在大田前期,72孔育苗方式下烟株的生长发育具有明显优势,团棵期的叶片干物质积累量比常规128孔处理下提高28.1%,但该优势随生育发育过程逐步减小。在成熟期,72孔育苗下烟株叶片干物质积累比128孔处理的提高3.2%并且在72孔处理下烟株最终出叶数虽比常规128孔减少0.5~1片,但最大叶长有所增加。二是72孔处理的烟株在烤后中部烟比例比常规128孔降低,产量提升。三是试验结果显示12月29日播种处理的烟株比12月22日播种烟株的产质量有所提升。四是烟株中部叶的结构、油分等外观品质在不同孔穴处理下差异不显著,但较早播种处理下的烟株中部叶身份比晚移栽有一定下降。 展开更多
关键词 烟株 育苗孔穴 播种时间 干物质积累 品质
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The relation between black hole masses and Lorentz factors of the jet components in blazars 被引量:1
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作者 Ming Zhou Xin-Wu Cao 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2009年第3期293-301,共9页
We explore the relationship between black hole mass (MBH) and the motion of the jet components for a sample of blazars. The Very Long Baseline Array (VLBA) 2 cm Survey and its continuation: Monitoring of Jets in ... We explore the relationship between black hole mass (MBH) and the motion of the jet components for a sample of blazars. The Very Long Baseline Array (VLBA) 2 cm Survey and its continuation: Monitoring of Jets in active galactic nuclei (AGNs) with VLBA Experiments (MOJAVE) have observed 278 radio-loud AGNs, of which 146 blazars have reliable measurements of their apparent velocities of the jet components. We calculate the minimal Lorentz factors for these sources from their measured apparent velocities, and their black hole masses are estimated with their broad-line widths. A significant intrinsic correlation is found between black hole masses and the minimal Lorentz factors of the jet components. The Eddington ratio is only weakly correlated with the minimal Lorentz factor, which may imply that the Blandford-Znajek (BZ) mechanism may dominate over the Blandford-Payne (BP) mechanism for the jet acceleration (at least) in blazars. 展开更多
关键词 black hole physics - galaxies activen galaxies jets - galaxies NUCLEI
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Radio Luminosity,Black Hole Mass and Eddington Ratio for Quasars from the Sloan Digital Sky Survey 被引量:1
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作者 Wei-Hao Bian Yan-Mei Chen +2 位作者 Chen Hu Kai Huang Yan Xu 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2008年第5期522-536,共15页
We investigate the MBH-σ* relation for radio-loud quasars with redshifl z 〈 0.83 in Data Release 3 of the Sloan Digital Sky Survey (SDSS). The sample consists of 3772 quasars with better models of the H/4 and [O ... We investigate the MBH-σ* relation for radio-loud quasars with redshifl z 〈 0.83 in Data Release 3 of the Sloan Digital Sky Survey (SDSS). The sample consists of 3772 quasars with better models of the H/4 and [O Ⅲ] lines and available radio luminosity, including 306 radio-loud quasars, 3466 radio-quiet quasars with measured radio luminosity or upper-limit of radio luminosity (181 radio-quiet quasars with measured radio luminosity). The virial supermassive black hole mass (MBH) is calculated from the broad Hβline, and the host stellar velocity dispersion (σ*) is traced by the core [O Ⅲ] gaseous velocity dispersion. The radio luminosity and radio loudness are derived from the FIRST catalog. Our results are as follows: (1) For radio-quiet quasars, we confirm that there is no obvious deviation from the MBH-σ* relation defined for inactive galaxies when the uncertainties in ~IBH and the luminosity bias are concerned. (2) We find that the radio-loud quasars deviate more from the MBH-σ* relation than do the radio-quiet quasars. This deviation is only partly due to a possible cosmological evolution of the MBH-σ* relation and the luminosity bias. (3) The radio luminosity is proportional to MBH1.28+0.23-0.16(LBol/LEdd) ^1.29+0.31-0.24 for radio-quiet quasars and to -MBH3.10+0.60-0.70(LBol/LEdd)^4.18+1.40-1.10 - for radio-loud quasars. The weaker dependence of the radio luminosity on the mass and the Eddington ratio for radio-loud quasars shows that other physical effects would account for their radio luminosities, such as the spin of the black hole. 展开更多
关键词 QUASARS emission lines - galaxies nuclei -galaxies bulges - black hole physics
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Hyperaccretion after the Blandford-Znajek Process:A New Model for GRBs with X-Ray Flares Observed in Early Afterglows 被引量:1
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作者 Wei-Hua Lei Ding-Xiong Wang Yuan-Chuan Zou Lei Zhang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2008年第4期404-410,共7页
We propose a three-stage model with Blandford-Znajek (BZ) and hyperaccretion process to interpret the recent observations of early afterglows of Gamma-Ray Bursts (GRBs). In the first stage, the prompt GRB is power... We propose a three-stage model with Blandford-Znajek (BZ) and hyperaccretion process to interpret the recent observations of early afterglows of Gamma-Ray Bursts (GRBs). In the first stage, the prompt GRB is powered by a rotating black hole (BH) invoking the BZ process. The second stage is a quiet stage, in which the BZ process is shut off, and the accretion onto the BH is depressed by the torque exerted by the magnetic coupling (MC) process. Part of the rotational energy transported by the MC process from the BH is stored in the disk as magnetic energy. In the third stage, the MC process is shut off when the magnetic energy in the disk accumulates and triggers magnetic instability. At this moment, the hyperaccretion process may set in, and the jet launched in this restarted central engine generates the observed X-ray flares. This model can account for the energies and timescales of GRBs with X-ray flares observed in early afterglows. 展开更多
关键词 accretion accretion disks - black hole physics - magnetic fields - gammarays BURSTS
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Entropy of Dilatonic Black Hole due to Arbitrary Spin Fields 被引量:1
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作者 You-Gen Shen and Chang-Jun Gao (Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 Institute of Theoretical Physics, Chinese Academy of Scienc 《Chinese Journal of Astronomy and Astrophysics》 CSCD 北大核心 2001年第4期357-364,共8页
Using the membrane model based on the brick-wall model, we calculate the free energy and entropy of dilatonic black hole due to arbitrary spin fields. The result shows that the entropy of scalar field and the entropy ... Using the membrane model based on the brick-wall model, we calculate the free energy and entropy of dilatonic black hole due to arbitrary spin fields. The result shows that the entropy of scalar field and the entropy of Fermionic field have similar formulas. There is only a numerical coefficient between them. 展开更多
关键词 black hole physics - entropy - spin
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Weak gravitational lensing of quantum perturbed lukewarm black holes and cosmological constant effect
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作者 Hossein Ghaffarnejad Mojtaba Amir Mojahedi 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2017年第6期17-36,共20页
The aim of the paper is to study weak gravitational lensing of quantum (perturbed) and classical lukewarm black holes (QLBHs and CLBHs respectively) in the presence of cosmological parameter A. We apply a numerica... The aim of the paper is to study weak gravitational lensing of quantum (perturbed) and classical lukewarm black holes (QLBHs and CLBHs respectively) in the presence of cosmological parameter A. We apply a numerical method to evaluate the deflection angle of bending light rays, image locations θ of sample sourceβ = π- 4, and corresponding magnifications μ. There are no obtained real values for Einstein ring locations θE(β = 0) for CLBHs but we calculate them for QLBHs. As an experimental test of our calculations, we choose mass M of 60 types of the most massive observed galactic black holes acting as a gravitational lens and study quantum matter field effects on the angle of bending light rays in the presence of cosmological constant effects. We calculate locations of non-relativistic images and corresponding magnifications. Numerical diagrams show that the quantum matter effects cause absolute values of the quantum deflection angle to be reduced with respect to the classical ones. The sign of the quantum deflection angle is changed with respect to the classical values in the presence of the cosmological constant. This means dominance of the anti-gravity counterpart of the cosmological horizon on the angle of bending light rays with respect to absorbing effects of 60 local types of the most massive observed black holes. Variations of the image positions and magnifications are negligible when increasing dimensionless cosmological constant ∈ = 16AM2 /2The deflection angle takes positive (negative) values for CLBHs (QLBHs) and they decrease very fast (slowly) by increasing the closest distance x0 of bending light ray and/or dimensionless cosmological parameter for sample giant black holes with 0.001 〈 ∈ 〈 0.01. 展开更多
关键词 gravitational lensing weak - strong - micro - stars black holes
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Do Radio-loud Active Galactic Nuclei really follow the same M_(BH)-σ_* Relation as Normal Galaxies?
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作者 Yi Liu Dong-Rong Jiang 《Chinese Journal of Astronomy and Astrophysics》 CSCD 2006年第6期655-662,共8页
In an examination of the relationship between the black hole mass MBH and stellar velocity dispersion σ* in radio-loud active galactic nuclei (AGNs), we studied two effects which may cause uncertainties in the bla... In an examination of the relationship between the black hole mass MBH and stellar velocity dispersion σ* in radio-loud active galactic nuclei (AGNs), we studied two effects which may cause uncertainties in the black hole mass estimates of radio-loud AGNs: the relativistic beaming effect on the observed optical continuum radiation and the orientation effect on the broad emission line width. After correcting these two effects, we re-examined the MBH- σ[OIII] relation for a sample of radio-loud and radio-quiet AGNs, and found the relation for radio-loud AGNs still deviated from that for nearby normal galaxies and radio-quiet AGNs. We also found there is no significant correlation between radio jet power and narrow [OIII] line width, indicating absence of strong interaction between radio jet and narrow line region. It may be that the deviation of the MBH-σ* relation of radio-loud AGNs is intrinsic, or that the [OIII] line width is not a good indicator of σ* for radio-loud AGNs. 展开更多
关键词 black hole physics - galaxies active - galaxies nuclei - quasars general
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