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Torsion Fields Generated by the Quantum Effects of Macro-bodies

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Research in Astronomy and Astrophysics 2022年第12期22卷 335-343页

作者： da-Ming chen National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

We generalize Einstein's General Relativity(GR)by assuming that all matter(including macro-objects)has quantum *** appropriate theory to fulfill this task is Gauge Theory Gravity(GTG)developed by the Cambridge *** is a“spin-torsion”theory,according to which,gravitational effects are described by a pair of gauge fields defined over a flat Minkowski background *** matter content is completely described by the Dirac spinor field,and the quantum effects of matter are identified as the spin tensor derived from the spinor *** existence of the spin of matter results in the torsion field defined over *** field plays the role of Bohmian quantum potential which turns out to be a kind of repulsive force as opposed to the gravitational potential which is *** equivalence principle remains and essential in this theory so that GR is relegated to a locally approximate theory wherein the quantum effects(torsion)are *** a toy model,we assume that the macro matter content can be described by the covariant Dirac equation and apply this theory to the simplest radially symmetric and static gravitational ***,by virtue of the cosmological principle,we are led to a static universe model in which the Hubble redshifts arise from the torsion fields.

关键词： cosmology:theory (cosmology:)dark matter (cosmology:)dark energy

Comparison of Modeling SPARC spiral galaxies’rotation curves:halo models ***

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Research in Astronomy and Astrophysics 2021年第11期21卷 10-18页

作者： Lin Wang da-Ming chen School of Physics and Electronics Henan UniversityKaifeng 475004China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China

The tension between luminous matter and dynamical matter has long been an interesting and controversial topic in the investigation of *** is particularly true when we study spiral galaxies for which we have high quality observations of rotation *** solutions to the tension are proposed in two different approaches,one is the dark matter hypothesis and the other is MOdified Newtonian Dynamics(MOND)*** we test the solutions by using observational data of rotation curves,the controversy arises when we apply them to both low surface brightness(LSB)galaxies and high surface brightness(HSB)*** one likes to use the rotation curves of LSB galaxies,since dark matter is needed or the Newtonian acceleration falls below the characteristic acceleration a0 in most regions of such galaxies,even near their *** for HSB galaxies,dark matter is needed or Newtonian acceleration falls below the characteristic acceleration a0 only in their outer regions so it is helpful to single out HSB galaxies from some large sample to test the *** this end,we employ a sub-sample of the rotation curves consisting of45 non-bulgy HSB galaxies selected from the Spitzer Photometry and Accurate Rotation Curves(SPARC)database to test two dark halo models(NFW and Burkert)and *** find that,among the three models,the core-dominated Burkert halo model(χ_(v)^(2)=1.00)provides a better description of the observed data than the NFW model(χ_(v)^(2)=1.44)or MOND model(χ_(v)^(2)=1.87).This is not consistent with the most recent numerical simulations,which tend to favor some cuspy density profiles for HSB *** MOND,when we take a0 as a free parameter,there is no obvious correlation between a0 and disk central surface brightness at 3.6μm of these HSB spiral galaxies,which is in line with the basic assumption of MOND that a0 should be a universal constant,but is surprisingly not consistent with the results when LSB galaxies are ***,our fi

关键词： cosmology:theory dark matter galaxies:halos

ON MAXIMA OF DUAL FUNCTION OF THE CDT SUBPROBLEM

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Journal of Computational Mathematics 2001年第2期19卷 113-124页

作者： Xiong-da chen Ya-xiang Yuan Reserach Development Center of Parallel Software Institute of SoftwareBeijing 100080China State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematics and Ssientific/Engineering ComputingAcademy of Mathematics and Systems SciencesChinese Academy of SciencesBeijing 100080China

Focuses on a study which determined the geometry meaning of the maxima of the CDT mathematical subproblem's dual function. Properties of trust region subproblem; Approximation of the CDT feasible region; Relations bet... 详细信息

关键词： trust region subproblem global minimizer approximation

Influence of steel corrosion on axial and eccentric compression behavior of coral aggregate concrete column

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Frontiers of Structural and Civil Engineering 2021年第6期15卷 1415-1425页

作者： Bo da Yan chen Hongfa YU Haiyan MA Bo YU da chen Xiao chen Zhangyu WU Jianbo GUO State Key Laboratory of Silicate Materials for Architectures Wuhan University of TechnologyWuhan 430070China College of Harbour Coastal and Offshore EngineeringHohai UniversityNanjing 210098China Key Laboratory of Coastal Disaster and Defence of Ministry of Education Hohai UniversityNanjing 210098China Guangxi Key Laboratory of Disaster Prevention and Engineering Safety Guangxi UniversityNanning 530004China Department of Civil and Airport Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

To study the behavior of coral aggregate concrete(CAC)column under axial and eccentric compression,the compression behavior of CAC column with different types of steel and initial eccentricity(ei)were tested,and the deformation behavior and ultimate bearing capacity(Nu)were *** results showed that as the ei increases,the Nu of CAC column decreases ***,the steel corrosion in CAC column is severe,which reduces the steel section and steel strength,and decreases the Nu of CAC *** durability of CAC structures can be improved by using new organic coated *** the influence of steel corrosion and interfacial bond deterioration,the calculation models of Nu under axial and eccentric compression were presented.

关键词： coral aggregate concrete column axial compression eccentric compression steel corrosion calculation model

Cusp-core problem and strong gravitational lensing

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Research in Astronomy and Astrophysics 2009年第11期9卷 1173-1184页

作者： Nan Li da-Ming chen National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

Cosmological numerical simulations of galaxy formation have led to the cuspy density profile of a pure cold dark matter halo toward the center, which is in sharp contradiction with the observations of the rotation curves of cold dark matter-dominated dwarf and low surface brightness disk galaxies, with the latter tending to favor mass profiles with a flat central core. Many efforts have been devoted to resolving this cusp-core problem in recent years, among them, baryon-cold dark matter interactions are considered to be the main physical mechanisms erasing the cold dark matter （CDM） cusp into a flat core in the centers of all CDM halos. Clearly, baryon-cold dark matter interactions are not customized only for CDM-dominated disk galaxies, but for all types, including giant ellipticals. We first fit the most recent high resolution observations of rotation curves with the Burkert profile, then use the constrained core size-halo mass relation to calculate the lensing frequency, and compare the predicted results with strong lensing observations. Unfortunately, it turns out that the core size constrained from rotation curves of disk galaxies cannot be extrapolated to giant ellipticals. We conclude that, in the standard cosmological paradigm, baryon-cold dark matter interactions are not universal mechanisms for galaxy formation, and therefore, they cannot be true solutions to the cusp-core problem.

关键词： cosmology dark matter -- galaxies formation -- galaxies halos -- galax- ies structure -- gravitational lensing

ATOMISTIC SIMULATION OF POINT DEFECTS IN NiAl ALLOY

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中国有色金属学会会刊：英文版 1997年第2期7卷 129-132页

作者： Liu, Zhenyun Lin, Dongliang chen, da Shanghai Jiao Tong Univ Shanghai China

ＡＴＯＭＩＳＴＩＣＳＩＭＵＬＡＴＩＯＮＯＦＰＯＩＮＴＤＥＦＥＣＴＳＩＮＮｉＡｌＡＬＬＯＹ①ＬｉｕＺｈｅｎｙｕｎ，ＬｉｎＤｏｎｇｌｉａｎｇ，ＣｈｅｎＤａＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅ，Ｓｈａｎ... 详细信息

ＡＴＯＭＩＳＴＩＣＳＩＭＵＬＡＴＩＯＮＯＦＰＯＩＮＴＤＥＦＥＣＴＳＩＮＮｉＡｌＡＬＬＯＹ①ＬｉｕＺｈｅｎｙｕｎ，ＬｉｎＤｏｎｇｌｉａｎｇ，ＣｈｅｎＤａＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅ，ＳｈａｎｇｈａｉＪｉａｏＴｏｎｇＵｎｉｖｅ...

关键词： NiAl intermetallic point defects computer simulation

Peak shrinking and interpolating for PAPR reduction in M-IFoF-based mobile fronthaul

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Digital Communications and Networks 2022年第1期8卷 51-57页

作者： Luping Qin Haibo Li da chen Tao Jiang Research Center of 6G Mobile Communications School of Cyber Science and Engineering Huazhong University of Science and Technology1037 Luoyu RoadWuhan 430074China State Key Laboratory of Optical Communication Technologies and Networks China Information Communication Technologies Group CorporationWuhan430074China

We apply a Peak Shrinking and Interpolating(PSI)scheme to improve the Peak-to-Average Power Ratio(PAPR)performance in Multiple Intermediate-Frequency-over-Fiber(M-IFoF)based mobile *** key idea is to detect the high peaks of the signal and shrink them,and then the shrunk peak values are interpolated into the original signal to reduce the *** also compare the PSI technique with the previous Tone-Reservation(TR)technique and Phase Pre-Distortion(PPD)technique in terms of PAPR reduction effect and computational *** simulation results indicate that the PSI scheme can reduce the PAPR by more than 4.3 dB at 0.1%CCDF,which outperforms the two previous schemes with lower computational ***,we find that altering M-IFoF system parameters has little effect on the performance of the PSI technique.

关键词： Mobile fronthaul Multi-IF-Over-Fiber(M-IFoF) Peak Shrinking and Interpolating(PSI) Tone-Reservation(TR) Phase Pre-Distortion(PPD)

On the Monotonicity of the Speed of Random Walks on a Percolation Cluster of Trees

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Acta Mathematica Sinica,English Series 2007年第11期23卷 1949-1954页

作者： da Yue chen Fu Xi ZHANG LMAM School of Mathematical Sciences Peking University Beijing 100871 P. R. China

The authors consider the simple random walk on the infinite cluster of the Bernoulli bond percolation of trees, and investigate the relation between the speed of the simple random walk and the retaining probability p ... 详细信息

关键词： random walk percolation speed monotonicity tree

Impact of finite-range tensor terms in the Gogny force on theβ-decay of magic nuclei

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Nuclear Science and Techniques 2021年第7期32卷 83-89页

作者： da-Zhuang chen Dong-Liang Fang Chun-Lin Bai College of Physics Sichuan UniversityChengdu 610065China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

Effects of finite-range tensor force onβ-decay of magic and semimagic nuclei of^(34)Si,^(68,78)Ni,and^(132)Sn have been investigated using the self-consistent Hartree–Fock plus random-phase approximation *** tensor force shifts the low-lying Gamow–Teller states downward and systematically improves the calculations of Q and logft ***,it systematically reduces the deviations between the theoretical and experimental data and significantly improves the calculation ofβ-decay *** effect is similar to that of zero-range tensor force.

关键词： tensor decay finite