检索结果-南通市图书馆

Geometry of Broad Line Regions of Active Galactic Nuclei

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2008年第1期8卷 50-62页

作者： Xiao-Rong Lü1 key laboratory for Particle Astro{2., institute of high energy physics, Chinese Academy of Sciences, {4. 10004. 2.Graduate School of Chinese Academy of Sciences, {4. 10004. key laboratory for Particle Astro{2. Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 Graduate School of Chinese Academy of Sciences Beijing 100049

It has long remained an open question as to the geometry of the broad line region （BLR） in active galactic nuclei （AGNs）. The reverberation mapping technique which measures the response of the broad emission lines to the ionizing continuum, when combined with multiwavelength continuum fitted by sophisticated accretion disks, provides a way of probing the BLR geometry. We analyze a sample of 35 AGNs, which have been monitored by the reverberation mapping campaign. In view of energy budget, the reverberation-based BH masses are found to be in agreement with those obtained by accretion disk models in two thirds of the present sample while the reverberation mapping methods underestimate the BH masses in about one third of objects, as also suggested by CoUin et al. in a recent work. We point out that there are obviously two kinds of BLR geometry, which are strongly dependent on the Eddington ratio, and separated by the value LBol/LEdd - 0.1. These results prefer a scenario of the disk and wind configuration of the BLR and identify the Eddington ratio as the physical driver regulating the wind in the BLR.

关键词： accretion, accretion disks - galaxies active - galaxies Seyfert - quasars general

Role of gallium wetting layer in high-quality ZnO growth on sapphire (0001) substrates

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2004年第5期47卷 612-620页

作者： ZENG Zhaoquan1,3, WANG Yong2. DU Xiaolong1, MEI Zengxia1, KONG Xianghe3, JIA Jinfeng1, XUE Qikun1 & ZHANG Ze2. 4.1. State key laboratory for Surface {2., institute of {2., Chinese Academy of Sciences, {4. 100080, China 2. laboratory of Electron Microscopy, institute of {2., Chinese Academy of Sciences, {4. 100080, China 3. College of {2. and Engineering, Qufu Normal University, Qufu 2.3165, China 4. {4. University of Technology, {4. 10002., China State key laboratory for Surface {2. Institute of Physics Chinese Academy of Sciences Beijing China College of physics and Engineering Qufu Normal University Qufu China laboratory of Electron Microscopy Institute of Physics Chinese Academy of Sciences Beijing China beijing University of Technology Beijing China

A Ga wetting layer was used to modify the surface structure of sapphire (0001) substrate to prepare high-quality ZnO film by radio frequency plasma-assisted molecule beam epitaxy. We found that this Ga layer plays a crucial role in eliminating 30 rotation domains, controlling polarity and decreasing defect density in ZnO epilayers, as demonstrated by in situ reflection high {2. electron diffraction, ex situ high resolution X-ray diffraction and high resolution cross-sectional transmission electron microscopy. Zn-polar film of ZnO was determined by convergent beam electron diffraction. A Ga bilayer model is proposed to understand the effects of the Ga wetting layer on high-quality ZnO growth.

关键词： Ga wetting layer, sapphire, polarity, defect density, zinc oxide, rf-MBE, RHEED, HRXRD, TEM, CBED.

Implementation of a multiple round quantum dense coding using nuclear magnetic resonance

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2005年第6期48卷 706-715页

作者： ZHANG Jingfu1, XIE Jingyi2. WANG Chuan1, DENG Zhiwei3, LU Zhiheng4. & LONG Guilu1,5 1. key laboratory For Quantum Information and Measurements of MOE, Department of {2., Tsinghua University, {4. 100084.China 2. Department of Materials Science and Engineering, {4. Normal University, {4. 100875, China 3. Testing and analytical Center, {4. Normal University, {4. 100875,China 4. Department of {2., {4. Normal University, {4. 100875, China 5. key laboratory For atomic and Molecular Nanosciences, Tsinghua University, {4. 100084.China key laboratory For Quantum Information and Measurements Department of Physics Tsinghua University Beijing 100084 China Department of Materials Science and Engineering Beijing Normal University Beijing 100875 China Testing and analytical Center Beijing Normal University Beijing 100875 China Department of physics Beijing Normal University Beijing 100875 China key laboratory for Atomic and Molecular Nanosciences Tsinghua University Beijing 100084 China

A multiple round quantum dense coding scheme based on the quantum phase estimation algorithm is proposed and implemented in a three qubit nuclear magnetic resonance (NMR) quantum computer. Using an m + 1 qubit system, Bob can transmit one of 2.+1 messages to Alice, through manipulating only one qubit and exchanging it between Alice and Bob for m rounds. The information capacity is enhanced to m + 1 bits as compared to m bits in a classical scheme. The scheme has been demonstrated in NMR system, and the experimental results show a good agreement between theory and experiment.

关键词： quantum dense coding, multiple round, nuclear magnetic resorance

Characterization of microarc oxidation coatings on pure titanium

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2003年第1期22卷 42-48页

作者： XUE Wenbin, WANG Chao, Li Yongliang, and CHEN Ruyikey laboratory for Beam Technology and Materials Modification, {2. of Low energy {4. {4., beijing Normal University, beijing 100875, China 北京师范大学射线束技术与材料改性教育部重点实验室北京 100875

key laboratory for Beam Technology and Materials Modification, {2. ofLow energy {4. {4., beijing Normal UniversityThe morphology, composition, and phase structure of the oxide coatings produced on the surface ofpure titanium by alternating-current microarc discharge in aluminate solution were investigated byX-ray diffraction and scanning electron microscopy. The profiles of the hardness H and the elasticmodulus E in the coatings were determined using a nanoindentation method. The concentrationdistributions of Ti, Al, and O in the coating show that this coating over 30 mu m thick contains twolayers: an outer layer and an inner layer. The oxide coating is mainly composed of TiO_2.rutile andAl_2.iO_5 compounds. During oxidation, the temperature in the microarc discharge channel was veryhigh to make the local coating molten. From the surface to the interior of the coating, H and Eincrease gradually, and then reach maximum values of 9.78 GPa and 176 GPa respectively at a distanceof 7 mu m from the coating/titanium interface. They are also rather high near the interface.

关键词： pure titanium ceramic coating microarc oxidation microstructure nanoindentation

On the knee of Galactic cosmic rays in light of sub-TeV spectral hardenings

在线全文

学校读者我要写书评

暂无评论

Chinese physics C 2018年第7期42卷 113-122页

作者： Yi-Qing Guo1 2.Qiang Yuan1 3 1. key laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory Chinese Academy of Sciences Nanjing 2.0008 China 2. key laboratory of Particle Astrophysics institute of {4. energy physics key laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of Sciences key laboratory of Particle Astro{2. Institute of High Energy PhysicsChinese Academy of Sciences School of Astronomy and Space Science University of Science and Technology of China

More than fifty years after the discovery of the knee in the cosmic ray （CR） spectra, its physical origin remains a mystery. This is partly due to the ambiguity of the energy spectra of individual components. Recently, direct measurements from several space experiments found significant spectral hardenings of CR nuclei at ~2.0 GV. A joint modeling of the direct and indirect measurements may help to understand the experimental systematics and the physics of the knee. In this work, we update the phenomenological ＂poly-gonato＂ model to include the spectral hardenings, with a changing spectral index of γ ＋ β·logE. This modification gives a reasonable description of the CR spectra in a wide energy range. However, the fits to different data sets give different results. We find that the fit to the AMS-02.and CREAM data slightly favors a relatively low energy knee of the light components. In such a case, the expected all-particle spectra under-shoot the data, which may require an extra component of CRs. The fits to AMS-02.data and the light component （H＋He） data from the Tibet ASγ/ARGO-YBJ/WFCTA and KASCADE experiments give consistent results with the all-particle spectra. We further propose a possible physical realization of such a ＂modified poly-gonato＂ model of spectral hardenings by means of spatially-dependent diffusion of CRs. We find reasonably good agreement between the model predictions and the data for CR spectra, the secondary-to-primary ratios, and the amplitude of anisotropies.

关键词： cosmic ray knee spectrum propagation

Magnetic moments of ^(33)Mg in the time-odd relativistic mean field approach

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2009年第10期52卷 1586-1592页

作者： LI Jian1,ZHANG Ying1,YAO JiangMing1 & MENG Jie1,2.1 School of physics,State key {2. of {4. physics and Technology,Peking University,{4. 100871,China 2.School of physics and {4. energy Engineering,Beihang University,{4. 100191,China School of physics State Key Laboratory of Nuclear Physics and Technology Peking University Beijing China School of physics and nuclear {2. Engineering Beihang University Beijing China

The configuration-fixed deformation constrained relativistic mean field approach with time-odd component has been applied to investigate the ground state properties of 33Mg with effective interaction *** ground state of 33Mg has been found to be prolate deformed,β2.0.2.,with the odd neutron in 1/2.330] orbital and the energy -2.1.85 MeV which is close to the data -2.2.06 *** magnetic moment -0.9134.μN is obtained with the effective electromagnetic current which well reproduces the data -0.74.6 μN self-consistently without introducing any *** energy splittings of time reversal conjugate states,the neutron current,the energy contribution from the nuclear magnetic potential,and the effect of core polarization are discussed in detail.

关键词： magnetic moment binding energy time-odd component configuration-fixed deformation constrained calculation relativistic mean field theory

Collision dynamics of He@C_(60)+He@C_(60) at low energies

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2008年第7期51卷 765-772页

作者： ZHAO Qiang1,2. ZHANG FengShou1,2.3 & ZHOU HongYu1,2.1 key {4. of Beam Technology and Material Modification of Ministry of Education, {2. of Low energy nuclear {4., beijing Normal University, beijing 100875, China 2.beijing Radiation Center, beijing 100875, China 3 Center of Theoretical nuclear {4., National {4. of Heavy Ion Accelerator of Lanzhou, Lanzhou 730000, China key laboratory of Beam Technology and Material Modification of Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing China beijing Radiation Center Beijing China Center of Theoretical nuclear physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China

A semi-empirical molecular dynamics model is developed. The central collisions of C60+C60 and He@C60+He@C60 at different incident energies are investigated based on this model. It is found that the dimer structures have been produced at proper incident energies and these fullerene dimers could be formed by a self-assembly of C60 fullerene and He@C60. The He atom has a significant effect at higher incident energy and this embedded He atom can enhance the stability of the dimer structure.

关键词： C60 He@C60 collision molecular dynamics

Anomalous magnetotransport in LaMn_(1-x)Te_xO_3

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2009年第7期52卷 987-992页

作者： TAN GuoTai1,2. CHEN ZhengHao3 & ZHANG XiaoZhong4.5 1 key laboratory of Beam Technology & Materials Modification of the Ministry of Education, {2. of Low {4. nuclear {4., beijing Normal University, beijing 100875, China 2.beijing Radiation Center, beijing 100875, China 3 laboratory of Optical {4., {2. of {4., Chinese Academy of Sciences, beijing 100080, China 4.key laboratory of Advanced Materials of the Ministry of Education, Department of Materials Science and Engineering, Tsinghua University, beijing 100084. China 5 beijing National Center for Electron Microscopy, Tsinghua University, beijing 100084. China key laboratory of Beam Technology & Materials Modification of the Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing China beijing Radiation Center Beijing China laboratory of Optical physics Institute of Physics Chinese Academy of Sciences Beijing China key laboratory of Advanced Materials of the Ministry of Education Department of Materials Science and Engineering Tsinghua University Beijing China beijing National Center for Electron Microscopy Tsinghua University Beijing China

The LaMn1-xTexO3+δ (x=0.1, 0.2. 0.3) were synthesized using solid-state reaction method for the first time. X-ray photoemission spectrum (XPS) shows that in the samples the Te ions have a valence of Te4., and Mn3+ ions are partly converted into Mn2. and Mn4. due to the excess oxygen and Te doping. The magnetotransport associated with Mn2., Mn3+ and Mn4. was investigated. The experimental results show that the samples are insulator at 0 T when the amount of Mn3+ is much larger or less than the sum of Mn2. and Mn4.; by contrast, the samples display metal to insulator transition with increasing temperature when the amount of Mn3+ is close to the sum of Mn2. and Mn4.. These anomalous magnetotransport behaviors were analyzed in the frame of the double-exchange (DE) mechanism.

关键词： colossal magnetoresistance La-Te-Mn-O magnetotransport

Properties of the 3/2.-[52.] band in the odd-N rare-earth nuclei

在线全文

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2011年第S1期54卷 37-43页

作者： CHEN Liang1,2. ZHOU XiaoHong1,2. ZHANG YuHu1, ZHANG ShuangQuan3 & ZHU LiHua4.1institute of Modern physics, Chinese Academy of Sciences, Lanzhou 730000, China 2.raduate University of Chinese Academy of Sciences, {2. 10004., China 3State key laboratory of {4. physics and Technology, School of physics, Peking University, {2. 100871, China 4.hina institute of Atomic energy, {2. 102.13, China institute of Modern physics Chinese Academy of Sciences Lanzhou China Graduate University of Chinese Academy of Sciences Beijing China State key laboratory of {2. physics and Technology School of Physics Peking University Beijing China China institute of Atomic energy Beijing China

high-spin states in 161Er have been studied experimentally via the 150Nd(16O, 5n) reaction at a beam energy of 86 MeV. Three rotational bands built on the 5/2.[64.2}, 3/2.[52.], and 11/2.[505] configurations have been extended up to high-spin states, and particularly, the α = -1/2.branch of the ground state 3/2.[52.] band has been revised significantly. It is found that signature inversion occurs in the 3/2.[52.] band after the band crossing in 161Er. The systematics of the signature inversion associated with the 3/2.[52.] configuration in the rare-earth region is discussed. The band properties are analyzed within the framework of a triaxial particle-rotor model, and a triaxial deformation is proposed to the 3/2.[52.] band.

关键词： high-spin states signature inversion triaxial particle-rotor model