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Predominance of linear Q and μ systematics in randominteraction ensembles

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Nuclear Science and Techniques 2018年第11期29卷 247-253页

作者： zhen-zhen qin Yang Lei School of Science Southwest University of Science and TechnologyMianyang 621010China School of National Defense Science and Technology Southwest University of Science and TechnologyMianyang 621010China

In random-interaction ensembles, the electric quadrupole moments(Q) and magnetic moments(μ) of the Iπ = 11/2-isomers of the Cd isotopes predominantly exhibit a linear correlation with the neutron numbers,corresponding to the recently emphasized linear Q and μsystematics in realistic nuclear systems. Although the seniority scheme enhances such predominance(more essentially for μ), the configuration mixing due to quadrupole-like and δ-force-like proton-neutron(pn) interactions is responsible for the linear Q and μ systematics,respectively, in realistic nuclear system, as well as randominteraction ensembles.

关键词： Random interaction Electromagnetic moment Linear systematics Proton–neutron interaction

Neural network study of the nuclear ground-state spin distribution within a random interaction ensemble

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Nuclear Science and Techniques 2024年第3期35卷 216-227页

作者： Deng Liu Alam Noor A zhen-zhen qin Yang Lei School of Mathematics and Physics Southwest University of Science and TechnologyMianyang 621010China School of Nuclear Science and Technology Southwest University of Science and TechnologyMianyang 621010China

The distribution of the nuclear ground-state spin in a two-body random ensemble(TBRE)was studied using a general classification neural network(NN)model with two-body interaction matrix elements as input features and the corresponding ground-state spins as labels or output *** quantum many-body system problem exceeds the capability of our optimized NNs in terms of accurately predicting the ground-state spin of each sample within the ***,our NN model effectively captured the statistical properties of the ground-state spin because it learned the empirical regularity of the ground-state spin distribution in TBRE,as discovered by physicists.

关键词： Neural network Two-body random ensemble Spin distribution of nuclear ground state

Structural,electronic,and magnetic properties of vanadium atom-adsorbed MoSe2 monolayer

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Chinese Physics B 2017年第2期26卷 392-398页

作者： Ping Llu zhen-zhen qin Yun-Liang Yue Xu Zuo College of Electronic Information and Optical Engineering Nankai University Tianjin 300071 China

Using the first-principles calculations, we study the structural, electronic, and magnetic properties of vanadium adsorbed MoSe_2 monolayer, and the magnetic couplings between the V adatoms at different adsorption concentrations. The calculations show that the V atom is chemically adsorbed on the MoSe_2 monolayer and prefers the location on the top of an Mo atom surrounded by three nearest-neighbor Se atoms. The interatomic electron transfer from the V to the nearestneighbor Se results in the polarized covalent bond with weak covalency, associated with the hybridizations of V with Se and Mo. The V adatom induces local impurity states in the middle of the band gap of pristine MoSe_2, and the peak of density of states right below the Fermi energy is associated with the V- dz^2 orbital. A single V adatom induces a magnetic moment of 5 μBthat mainly distributes on the V-3d and Mo-4d orbitals. The V adatom is in high-spin state, and its local magnetic moment is associated with the mid-gap impurity states that are mainly from the V-3d orbitals. In addition,the crystal field squashes a part of the V-4s electrons into the V-3d orbitals, which enhances the local magnetic *** magnetic ground states at different adsorption concentrations are calculated by generalized gradient approximations（GGA） and GGA＋U with enhanced electron localization. In addition, the exchange integrals between the nearest-neighbor V adatoms at different adsorption concentrations are calculated by fitting the first-principle total energies of ferromagnetic（FM） and antiferromagnetic（AFM） states to the Heisenberg model. The calculations with GGA show that there is a transition from ferromagnetic to antiferromagnetic ground state with increasing the distance between the V adatoms. We propose an exchange mechanism based on the on-site exchange on Mo and the hybridization between Mo and V, to explain the strong ferromagnetic coupling at a short distance between the V adatoms. However, the ferromagneti

关键词： V-adatom MoSe2 monolayer magnetic moment magnetic coupling first-principles calculation

A Chandra study of the massive, distant galaxy cluster SDSS J0150–1005

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Research in Astronomy and Astrophysics 2013年第10期13卷 1155-1162页

作者： zhen-zhen qin Hai-Guang Xu Jing-Ying Wang Jun-Hua Gu Department of Physics Shanghai Jiao Tong University National Astronomical Observatories Chinese Academy of Sciences

We present a study of a fossil cluster,SDSS J0150–1005（z 0.364）,with high spatial resolution based on the imaging spectroscopic analysis of Chandra *** Chandra X-ray image shows a relaxed and symmetric morphology,which indicates that SDSS J0150–1005 is a well-developed galaxy cluster with no sign of a recent *** to the isothermal model,its global gas temperature is 5.73±0.80 keV,and the virial mass is 6.23±1.34×1014M⊙.Compared with the polytropic temperature model,the mass calculated based on the isothermal model is overestimated by 49%±*** central gas entropy,S0.1 r200=143.9±18.3 keV cm2,is significantly lower than the average value of normal galaxy clusters with similar *** results indicate that SDSS J0150–1005 formed during an early epoch.

关键词： galaxies:clusters:general galaxies:evolution galaxies:halos—intergalactic medium X-rays:galaxies:clusters

Insight into vertical piezoelectric characteristics regulated thermal transport in van der Waals two-dimensional materials

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Rare Metals 2024年第2期43卷 770-779页

作者： Dong-Hai Wei E Zhou Jin-Yuan Xu Hui-Min Wang Chen Shen Hong-Bin Zhang zhen-zhen qin Guang-Zhao qin State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha410082China Hunan Key Laboratory for Micro-Nano Energy Materials and Device and School of Physics and Optoelectronics Xiangtan UniversityXiangtan411105China Institute of Materials Science Technical University of DarmstadtAlarich-Weiss-Str.264287DarmstadtGermany School of Physics and Microelectronics Zhengzhou UniversityZhengzhou450001China

The urgent demand of extreme(ultra-high/low)thermal conductivity materials is triggered by the high-power device,where exploring the theories and mechanisms of regulating thermal transport properties plays a key ***,we elaborately investigate the effect of vertical(out-of-plane)piezoelectric characteristics on thermal transport,which is historically *** different stacking-order(AA and AB)bilayer boron nitride(Bi-BN)in two-dimensional(2D)materials are selected as study *** performing state-of-the-art first-principles calculations,it is found that the polarization charge along the out-of-plane orientation ascends significantly with the increasing piezoelectric response in AB stacked Bi-BN(Bi-BN-AB)followed by the enhanced interlayer B–N atomic ***,the amplitude of phonon anharmonicity in Bi-BN-AB increases larger than that in the AA stacked Bi-BN(Bi-BN-AA),resulting in the dramatic weakening of the thermal conductivity by 20.34%under 18%*** research reveals the significant role of the vertical(out-of-plane)piezoelectric characteristic in regulating thermal transport and provides new insight into accurately exploring the thermal transport performance of 2D van der Waals materials.

关键词： Thermal conductivity Piezoelectric effect 2D materials Bilayer BN Strain engineering

Metal enrichment via ram pressure stripping in the IGM of the compact galaxy group RGH 80

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Research in Astronomy and Astrophysics 2010年第4期10卷 301-308页

作者： Hai-Juan Cui Hai-Guang Xu Jun-Hua Gu Jing-Ying Wang Li-Yi Gu Yu Wang zhen-zhen qin Tao An Department of Physics Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

By creating and analyzing two dimensional gas temperature and abundance maps of the RGH 80 compact galaxy group with high-quality Chandra data,we detect a high-abundance （ 0.7 Z⊙） arc,where the metal abundance is significantly higher than the surrounding regions by 0.3Z⊙.This structure shows tight spatial correlations with the member galaxy PGC 046529,as well as with the arm-like feature identified on the X-ray image in the previous work of Randall et al.（2009）.Since no apparent signature of AGN activity is found to be associated with PGC 046529 in multi-band observations,and the gas temperature,metallicity,and mass of the high-abundance arc resemble those of the ISM of typical early-type galaxies,we conclude that this high-abundance structure is the remnant of the ISM of PGC 046529,which was stripped out of the galaxy by ram pressure stripping due to the motion of PGC 046529 in RGH *** novel case shows that ram pressure stripping can work as efficiently in the metal enrichment process in galaxy groups as it can in galaxy clusters.

关键词： galaxies:clusters:individual (RGH 80) - galaxy:abundance - intergalactic medium - X-rays:galaxies:clusters

Biases in hydrostatic mass profiles introduced by hot gas substructures:Chandra study of four galaxy clusters

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Research in Astronomy and Astrophysics 2010年第10期10卷 1005-1012页

作者： Li-Yi Gu Yu Wang Jun-Hua Gu Jing-Ying Wang zhen-zhen qin Meng-Yu Yao Jian-Long Yang Hai-Guang Xu Department of Physics Shanghai Jiao Tong University Shanghai 200240 China

By analyzing the azimuthal variations of total gravitating mass profiles in the central 300 h^-1 71 kpc regions of four galaxy clusters with Chandra data, we find that the azimuthally-averaged mass profiles may have been systematically underestimated by 16^＋9 -8% at lσ significance in the 50-100 h^-1 71 kpc regions, probably due to the prevailing existence of 2-D hot gas substructures in 100-300h^-1 71 kpc. The mass biases become negligible（-7＋11 _9＋ %） at 〉 150 h^-1 71 kpc. We confirm the results that the gas temperature maps can be used to probe the departure from hydrostatic equilibrium and help quantify the systematic biases in X-ray mass measurements in the central regions of clusters.

关键词： cosmology dark matter -- galaxies clusters general -- galaxies inter-galactic medium -- X-rays galaxies clusters

Group-scale asymmetric abundance structures in the NGC 533 group

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Research in Astronomy and Astrophysics 2012年第1期12卷 63-74页

作者： Jun-Hua Gu Hai-Guang Xu Jing-Ying Wang Yu Wang Shao-Feng Xu zhen-zhen qin Li-Yi Gu Tao An Zhong-Li Zhang Min Lei Department of Physics Shanghai Jiao Tong University Shanghai 200240 China Shanghai Astronomical Observatory Shanghai 200030 China. Department of Physics School of Science The University of Tokyo 7-3-1 Hongo Bunkyo-kuTokyo 113-0033 Japan Max-Planck-Institute of Astrophysics Karl-Schwarzschild-Str. 1 Postfach 1317 85741Garching Munich Germany School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China

By performing a two dimensional spectral analysis on the galaxy group NGC 533 with high-quality Chandra data, we find that the metal abundance distribution in this group is anisotropic. In the area around 2.5′ from the center, we find two concentrations of high abundance structures, in which the abundances are significantly higher than their surrounding regions at the 90% confidence level. We find that the total iron mass in these two regions agrees with the iron mass synthesized in the central dominant galaxy in n 19＋0.08 Gyr. The double-sided configuration of the high abun- 0.03 dance structure, together with the point-like radio emission in the center suggests that the abundance structures could have been transported from the center to their present positions by active galactic nucleus （AGN） activity. We further calculate the energy required for transport, and find that it could have been supplied during an AGN period. However, considering that this group is reported to have experienced a recent merger, the possibility that this merger is responsible for the abundance structures still cannot be excluded.

关键词： galaxies: clusters: individual (NGC 533) -- galaxy: abundances -- in-tergalactic medium -- X-rays: galaxies: clusters

红外光谱法研究古代彩绘蛋白胶料光老化的二级结构变化

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光谱学与光谱分析 2017年第9期37卷 2712-2716页

作者：马珍珍王丽琴 Gabriela Krist Tatjana Bayerova 杨璐西北大学文化遗产学院陕西西安710069 文化遗产研究与保护技术教育部重点实验室陕西西安710069 Institute of Conservation and Restoration University of Applied Arts Vienna

动物胶和蛋清是古代重要彩绘文物蛋白胶结材料,对其光老化蛋白质结构变化的研究与探索彩绘文物病变机理和选择科学保护材料、修复方法密切相关。以维也纳艺术历史博物馆的动物胶(骨胶、兔皮胶、鲟鱼胶)和蛋清为研究对象,利用红外光谱技... 详细信息

动物胶和蛋清是古代重要彩绘文物蛋白胶结材料,对其光老化蛋白质结构变化的研究与探索彩绘文物病变机理和选择科学保护材料、修复方法密切相关。以维也纳艺术历史博物馆的动物胶(骨胶、兔皮胶、鲟鱼胶)和蛋清为研究对象,利用红外光谱技术,结合酰胺Ⅰ带去卷积和高斯拟合法研究光老化过程中蛋白质二级结构的改变。结果表明,四种胶光老化后仍然具备蛋白质红外光谱的典型吸收特征。但红外吸收峰出现了不同程度的位移,其中蛋清糖苷键明显蓝移。酰胺Ⅰ带去卷积和高斯拟合结果显示,蛋白胶的二级结构占比发生了改变。其中,骨胶α-螺旋结构占比降低22.24%,逐渐解螺旋,无规则卷曲结构占比明显增高(9.76%);兔皮胶和鲟鱼胶α-螺旋结构占比分别降低5.31%,4.15%,前者无规则卷曲增幅最低(6.96%),后者反而减少,推测两者的光老化稳定性高。蛋清α-螺旋占比降低程度最高(44.45%),无规则卷曲占比增幅极大(27.49%),光老化稳定性最差。证实利用红外光谱技术,结合酰胺Ⅰ带去卷积和高斯拟合法研究文物蛋白胶料二级结构变化的方法是可行的,但其转化机理还需后期进一步探讨。

关键词：红外光谱蛋白胶料文物光老化二级结构高斯拟合