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Extension of covariant derivative(Ⅰ): From component form to objective form 被引量:4
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作者 Ya-Jun Yin 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第1期79-87,共9页
This paper extends the covariant derivative un der curved coordinate systems in 3D Euclid space. Based on the axiom of the covariant form invariability, the classical covariant derivative that can only act on componen... This paper extends the covariant derivative un der curved coordinate systems in 3D Euclid space. Based on the axiom of the covariant form invariability, the classical covariant derivative that can only act on components is ex tended to the generalized covariant derivative that can act on any geometric quantity including base vectors, vectors and tensors. Under the axiom, the algebra structure of the gen eralized covariant derivative is proved to be covariant dif ferential ring. Based on the powerful operation capabilities and simple analytical properties of the generalized covariant derivative, the tensor analysis in curved coordinate systems is simplified to a large extent. 展开更多
关键词 Tensor analysis Classical covariant derivatives Generalized covariant derivatives The axiom of the covari-ant form invariability covariant differential ring
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Extension of covariant derivative(Ⅱ): From flat space to curved space 被引量:4
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作者 Ya-Jun Yin 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第1期88-95,共8页
This paper extends the classical covariant deriva tive to the generalized covariant derivative on curved sur faces. The basement for the extension is similar to the pre vious paper, i.e., the axiom of the covariant fo... This paper extends the classical covariant deriva tive to the generalized covariant derivative on curved sur faces. The basement for the extension is similar to the pre vious paper, i.e., the axiom of the covariant form invariabil ity. Based on the generalized covariant derivative, a covari ant differential transformation group with orthogonal duality is set up. Through such orthogonal duality, tensor analy sis on curved surfaces is simplified intensively. Under the covariant differential transformation group, the differential invariabilities and integral invariabilities are constructed on curved surfaces. 展开更多
关键词 Tensor analysis on curved surfaces Classicalcovariant derivative and generalized covariant derivative Axiom of the covariant form invariability covariant differ-ential transformation group Differential invariabilities andintegral invariabilities
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Generalized covariant differentiation and axiom-based tensor analysis 被引量:3
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作者 Yajun YIN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2016年第3期379-394,共16页
This paper reports the new progresses in the axiomatization of tensor anal- ysis, including the thought of axiomatization, the concept of generalized components, the axiom of covariant form invariability, the axiomati... This paper reports the new progresses in the axiomatization of tensor anal- ysis, including the thought of axiomatization, the concept of generalized components, the axiom of covariant form invariability, the axiomatized definition, the algebraic structure, the transformation group, and the simple calculation of generalized covariant differentia- tions. These progresses strengthen the tendency of the axiomatization of tensor analysis. 展开更多
关键词 tensor analysis axiom of covariant form invariability generalized compo-nent generalized covariant differentiation covariant differential transformation group
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Extension of covariant derivative(Ⅲ): From classical gradient to shape gradient 被引量:4
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作者 Ya-Jun Yin 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2015年第1期96-103,共8页
This paper further extends the generalized covari ant derivative from the first covariant derivative to the sec ond one on curved surfaces. Through the linear transforma tion between the first generalized covariant de... This paper further extends the generalized covari ant derivative from the first covariant derivative to the sec ond one on curved surfaces. Through the linear transforma tion between the first generalized covariant derivative and the second one, the second covariant differential transformation group is set up. Under this transformation group, the sec ond class of differential invariants and integral invariants on curved surfaces is made clear. Besides, the symmetric struc ture of the tensor analysis on curved surfaces are revealed. 展开更多
关键词 Tensor analysis on curved surfaces The sec-ond generalized covariant derivative The second covariantdifferential transformation group The second class of dif-ferential and integral invariants
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Stability of the linear chain structure for 12C in covariant density functional theory on a 3D lattice 被引量:4
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作者 ZhengXue Ren ShuangQuan Zhang +3 位作者 PengWei Zhao Naoyuki Itagaki Joachim AMaruhn Jie Meng 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2019年第11期6-13,共8页
The stability of the linear chain structure of three α clusters for 12C against the bending and fission is investigated in the cranking covariant density functional theory, in which the equation of motion is solved o... The stability of the linear chain structure of three α clusters for 12C against the bending and fission is investigated in the cranking covariant density functional theory, in which the equation of motion is solved on a 3D lattice with the inverse Hamiltonian and the Fourier spectral methods. Starting from a twisted three α initial configuration, it is found that the linear chain structure is stable when the rotational frequency is within the range of ~2.0-~2.5 MeV. Beyond this range, the final states are not stable against fission. By examining the density distributions and the occupation of single-particle levels, however, these fissions are found to arise from the occupation of unphysical continuum with large angular momenta. To properly remove these unphysical continuum, a damping function for the cranking term is introduced. Eventually, the stable linear chain structure could survive up to the rotational frequency ~3.5 MeV, but the fission still occurs when the rotational frequency approaches ~4.0 MeV. 展开更多
关键词 covariant density functional theory cranking model 3D LATTICE space linear chain STRUCTURE alpha-cluster STRUCTURE COLLECTIVE ROTATION 12C
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基于LSTM网络的川东地区月降水量预测 被引量:6
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作者 陈慧 齐振方 《水电能源科学》 北大核心 2021年第8期14-17,13,共5页
降水量时间序列变化模拟对揭示全球气候变化规律和认识地表水文过程具有重要意义。基于1981~2005年川东地区降水观测资料,采用长短期记忆神经网络(LSTM)构建降水量逐月预测模型,预测2006~2019年逐月降水变化特征,并比较不同协变量下基于... 降水量时间序列变化模拟对揭示全球气候变化规律和认识地表水文过程具有重要意义。基于1981~2005年川东地区降水观测资料,采用长短期记忆神经网络(LSTM)构建降水量逐月预测模型,预测2006~2019年逐月降水变化特征,并比较不同协变量下基于LSTM和随机森林(RF)模型的降水量预测精度。结果表明,LSTM模型在以气候因子(C)与历史降水资料(H)为输入变量时比单独输入C、H变量条件下具有更高精度,其N_(S)E达0.50,M_(RE)、R_(MSE)分别为29.15%、38.72 mm;与RF模型相比,基于LSTM降水量预测模型具有更高预测性能,其N_(SE)比RF模型提高0.06,M_(RE)、R_(MSE)减小3.43%、3.66mm;川东地区降水量预测模型精度分布具有空间异质性,呈自东南部平原向北部山地减少的分布特征。 展开更多
关键词 LSTM模型 降水量预测 时间序列 协变量
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Generalized Covariant Derivative with Respect to Time in Flat Space(Ⅰ):Eulerian Description 被引量:2
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作者 Yajun Yin 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2016年第4期345-358,共14页
This paper reports a new derivative in the Eulerian description in flat space-the generalized covariant derivative with respect to time. The following contents are included:(a) the restricted covariant derivative with... This paper reports a new derivative in the Eulerian description in flat space-the generalized covariant derivative with respect to time. The following contents are included:(a) the restricted covariant derivative with respect to time for Eulerian component is defined;(b) the postulate of the covariant form invariability in time field is set up;(c) the generalized covariant derivative with respect to time for generalized Eulerian component is defined;(d) the algebraic structure of the generalized covariant derivative with respect to time is made clear;(e) the covariant differential transformation group in time filed is derived. These progresses reveal the covariant form invariability of Eulerian space and time. 展开更多
关键词 Eulerian description covariant form invariability generalized Eulerian component generalized covariant derivative with respect to time covariant differential transformation group
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Generalized Covariant Derivative with Respect to Time in Flat Space(Ⅱ):Lagrangian Description 被引量:2
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作者 Yajun Yin 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2016年第4期359-370,共12页
The previous paper reported a new derivative in the Eulerian description in flat space—the generalized covariant derivative of generalized Eulerian component with respect to time. This paper extends the thought from ... The previous paper reported a new derivative in the Eulerian description in flat space—the generalized covariant derivative of generalized Eulerian component with respect to time. This paper extends the thought from the Eulerian description to the Lagrangian description:on the basis of the postulate of covariant form invariability in time field, we define a new derivative in the Lagrangian description in flat space—the generalized covariant derivative of generalized Lagrangian component with respect to time. Besides, the covariant differential transformation group is set up. The covariant form invariability of Lagrangian space-time is ascertained. 展开更多
关键词 Lagrangian description the postulate of covariant form invariability generalized Lagrangian component generalized covariant derivative with respect to time covariant differential transformation group
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α-cluster structure of ^(12)C and ^(16)O in the covariant density functional theory with a shell-model-like approach 被引量:3
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作者 刘朗 赵鹏巍 《Chinese Physics C》 SCIE CAS CSCD 2012年第9期818-822,共5页
The α-cluster structures for 12^C and 16^O are investigated in the framework of the covariant density functional theory, where the pairing correlation is treated with a particle number conserving shell-model-like app... The α-cluster structures for 12^C and 16^O are investigated in the framework of the covariant density functional theory, where the pairing correlation is treated with a particle number conserving shell-model-like approach. The ground states of 12^C and 160 have been calculated and the density distributions demonstrate an equilateral triangle 3α clustering for 12^C and a regular tetrahedron 4α clustering for 16^O The existence of linear nα chain structure of both 12^C and 16^O is revealed at high quadrupole deformation. 展开更多
关键词 pairing correlation α-cluster covariant density functional theory shell-model-like approach
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W^t-approximation representations over quasi k-Gorenstein algebras 被引量:3
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作者 黄兆泳 《Science China Mathematics》 SCIE 1999年第9期945-956,共12页
The notions of quasi k-Gorenstein algebras and W^t-approximation representations are introduced. The existence and uniqueness (up to projective equivalences) of W^t-approximation representations over quasi k-Gorenstei... The notions of quasi k-Gorenstein algebras and W^t-approximation representations are introduced. The existence and uniqueness (up to projective equivalences) of W^t-approximation representations over quasi k-Gorenstein algebras are established. Some applications of W^t-approximation representations to homologically finite subcategories are given. 展开更多
关键词 W t -approximation representations quasik-Gorenstein algebras contravariant finiteness covariant finiteness
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g factors of nuclear low-lying states:A covariant description 被引量:5
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作者 YAO JiangMing PENG Jing +1 位作者 MENG Jie RING Peter 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第2期198-203,共6页
The g factors and spectroscopic quadrupole moments of low-lying excited states 2+1,…,81+ in 24Mg are studied in a covariant density functional theory.The wave functions are constructed by configuration mixing of axia... The g factors and spectroscopic quadrupole moments of low-lying excited states 2+1,…,81+ in 24Mg are studied in a covariant density functional theory.The wave functions are constructed by configuration mixing of axially deformed mean-field states projected on good angular momentum.The mean-field states are obtained from the constraint relativistic point-coupling model plus BCS calculations using the PC-F1 parametrization for the particle-hole channel and a density-independent delta-force for the particle-particle channel.The available experimental g factor and spectroscopic quadrupole moment of 21+ state are reproduced quite well.The angular momentum dependence of g factors and spectroscopic quadrupole moments,as well as the effects of pairing correlations are investigated. 展开更多
关键词 covariant density functional theory magnetic moment g factor spectroscopic quadrupole moment
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Leading order relativistic chiral nucleon-nucleon interaction 被引量:2
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作者 任修磊 李凯文 +3 位作者 耿立升 龙炳蔚 Peter Ring 孟杰 《Chinese Physics C》 SCIE CAS CSCD 2018年第1期97-106,共10页
Motivated by the successes of relativistic theories in studies of atomic/molecular and nuclear systems and the need for a relativistic chiral force in relativistic nuclear structure studies, we explore a new relativis... Motivated by the successes of relativistic theories in studies of atomic/molecular and nuclear systems and the need for a relativistic chiral force in relativistic nuclear structure studies, we explore a new relativistic scheme to construct the nucleon-nucleon interaction in the framework of covariant chiral effective field theory. The chiral interaction is formulated up to leading order with covariant power counting and a Lorentz invariant chiral Lagrangian.We find that the relativistic scheme induces all six spin operators needed to describe the nuclear force. A detailed investigation of the partial wave potentials shows a better description of the;S——0 and;P;phase shifts than the leading order Weinberg approach, and similar to that of the next-to-leading order Weinberg approach. For the other partial waves with angular momenta J≥1, the relativistic results are almost the same as their leading order non-relativistic counterparts. 展开更多
关键词 covariant chiral perturbation theory nucleon-nucleon interaction relativistic scattering equation
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Twisted Semigroup Crossed Products and Twisted Toeplitz Algebras of Ordered Groups 被引量:2
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作者 Sriwulan ADJI Rizky ROSJANUARDI 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2007年第9期1639-1648,共10页
Let г^+ be the positive cone of a totally ordered abelian group г, and σa cocycle in г. We study the twisted crossed products by actions of г+ as endomorphisms of C^*-algebras, and use this to generalize the t... Let г^+ be the positive cone of a totally ordered abelian group г, and σa cocycle in г. We study the twisted crossed products by actions of г+ as endomorphisms of C^*-algebras, and use this to generalize the theorem of Ji. 展开更多
关键词 projective isometric representation covariant representation semigroup dynamical system twisted semigroup crossed product twisted Toeplitz algebra
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A Quantum Representation of the Homogeneous 5D Manifold and the Perelman Mappings of 5D onto Non-Homogeneous Lorentz 4D Manifolds 被引量:2
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作者 Kai Wai Wong Peter Chin Wan Fung Wan Ki Chow 《Journal of Modern Physics》 2019年第5期557-575,共19页
The expression of the Maxwell magnetic monopole was employed to correlate the space to space projection that gives rise to the Gell-Mann standard model, and space to time projection which gives the leptons;and how doe... The expression of the Maxwell magnetic monopole was employed to correlate the space to space projection that gives rise to the Gell-Mann standard model, and space to time projection which gives the leptons;and how does it correlate to the Perelman mappings from the homogeneous 5D manifold to the Lorentz 4D manifold, together with correlating the physical consequences caused by the breaking of the Diagonal Long Range Order [DLRO] of the monopoles quantum states affected by the motion of massive particles in the Lorentz 4D boundary of the 5D manifold, which leads to gravitons and the gravity field via the General Relativity covariant Riemannian 4D curvatures metric equation. 展开更多
关键词 5D HOMOGENEOUS MANIFOLD Perelman MAPPINGS Magnetic MONOPOLES Space Projections and Topological Symmetries covariant RIEMANNIAN Curvature and Gravity
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Static or dynamic pear shapes in radioactive nucleus ^(224)Rn?
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作者 Xian-Ye Wu Jin-Ze Cao +3 位作者 Kun-Ning Zhao Zhong-Min Liu Jian Xiang En-Fu Zhou 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第11期164-173,共10页
We report a comprehensive study on low-lying parity doublet states of ^(224)Rn by mixing both quadrupole-and octupoleshaped configurations in multireference covariant density functional theory,in which broken symmetri... We report a comprehensive study on low-lying parity doublet states of ^(224)Rn by mixing both quadrupole-and octupoleshaped configurations in multireference covariant density functional theory,in which broken symmetries in configurations are restored using projection techniques.The low-lying energy spectrum is reasonably reproduced when the shape fluctuations in both the quadrupole and octupole shapes are considered.Electric octupole transition strength in ^(224)Rn is found to be B(E3;3_(1)^(-)→0_(1)^(+))=43 W.u.,comparable to that in ^(224)Ra,whose data are 42(3)W.u..Our results indicate that ^(224)Rn shares similar low-energy structure with ^(224)Ra despite the excitation energy of first 3^(−)state of the former nucleus is higher than that of the latter.This study suggests ^(224)Rn is a candidate for the search for permanent electric dipole moment. 展开更多
关键词 covariant density functional theory Parity doublet bands Octupole correlations Electric transition strengths
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Holographic dark energy in non-conserved gravity theory
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作者 H R Fazlollahi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2024年第4期126-133,共8页
Recently, reconsidering the Rastall idea T_(μ;νν)^(v)=α_(,μ) through relativistic thermodynamics gives a new form for the scalar field α which led us to construct modern modified theory of gravity debugged ‘non... Recently, reconsidering the Rastall idea T_(μ;νν)^(v)=α_(,μ) through relativistic thermodynamics gives a new form for the scalar field α which led us to construct modern modified theory of gravity debugged ‘non-conserved gravity theory’ Fazlollahi 2023 Euro. Phys. J. C 83 923. This theory unlike other modified theories of gravity cannot directly explain the current acceleration expansion in the absence of the cosmological constant and or existence of other forms of dark energy. Hence, in this study we have reinvestigated holographic dark energy Ρ_(X)~H^(2) in the non-conserved theory of gravity. In this context, the density and pressure of dark energy depend on the non-conserved term and density of the dust matter field. As shown, due to non-conservation effects on large-scale structures, unlike the original holographic model, our model onsets an acceleration epoch for the current Universe satisfies observations. Moreover, the interaction and viscous scenarios are studied for this model. 展开更多
关键词 non-conserved gravity covariant form of thermodynamics holographic dark energy
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Evolution of N=20,28,50 shell closures in the 20≤Z≤30 region in deformed relativistic Hartree-Bogoliubov theory in continuum
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作者 郑茹尤 孙向向 +1 位作者 申国防 耿立升 《Chinese Physics C》 SCIE CAS CSCD 2024年第1期144-153,共10页
Magicity,or shell closure,plays an important role in our understanding of complex nuclear phenomena.In this work,we employ one of the state-of-the-art density functional theories,the deformed relativistic Hartree-Bogo... Magicity,or shell closure,plays an important role in our understanding of complex nuclear phenomena.In this work,we employ one of the state-of-the-art density functional theories,the deformed relativistic Hartree-Bogoliubov theory in continuum(DRHBc)with the density functional PC-PK1,to investigate the evolution of the N=20,28,50 shell closures in the 20≤Z≤30 region.We show how these three conventional shell closures evolve from the proton drip line to the neutron drip line by studying the charge radii,two-neutron separation energies,two-neutron gaps,quadrupole deformations,and single-particle levels.In particular,we find that in the 21≤Z≤27 region,the N=50 shell closure disappears or becomes quenched,mainly due to the deformation effects.Similarly,both experimental data and theoretical predictions indicate that the N=28 shell closure disappears in the Mn isotopic chain,mainly due to the deformation effects.The DRHBc theory predicts the existence of the N=20 shell closure in the Ca,Sc,and Ti isotopic chains,but the existing data for the Ti isotopes suggest the contrary,and therefore further research is needed. 展开更多
关键词 shell evolution covariant density functional theories magic numbers
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Radiative decays D*(s)→ D(s)γ in covariant confined quark model
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作者 C.T.Tran M.A.Ivanov +1 位作者 P.Santorelli Q.C.Vo 《Chinese Physics C》 SCIE CAS CSCD 2024年第2期45-56,共12页
Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢCollaborations.The radiative couplings gD*Dγencoding nonperturbative QCD effects are calculated in the framewo... Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢCollaborations.The radiative couplings gD*Dγencoding nonperturbative QCD effects are calculated in the framework of the covariant confined quark model developed by us.We compare our results with other theoretical studies and experimental data.The couplings(in GeV-1)|g(D*+D+γ)|=0.45(9)and|g(D*0D0γ)|=1.72(34)calculated in our model agree with the corresponding experimental data|g(D*+D+γ)|=0.47(7)and|g(D*0D0γ)|=1.77(16).The most interesting case is the decay Ds*→Dsγ,for which a recent prediction based on light-cone sum rules at next-to-leading order|gDs*Dsγ|=0.60(19)deviates from the first(and only to date)lattice QCD result|gDs*Dsγ|=0.11(2)at nearly3σ.Our calculation yields|gDs*Dsγ|=0.29(6),which falls somehow between the two mentioned results,although it is larger than those predicted in other studies using quark models or QCD sum rules. 展开更多
关键词 covariant quark model radiative decay charmed meson
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Moments of inertia of triaxial nuclei in covariant density functional theory
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作者 Yu-Meng Wang Qi-Bo Chen 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第10期197-207,共11页
The covariant density functional theory(CDFT)and five-dimensional collective Hamiltonian(5DCH)are used to analyze the experimental deformation parameters and moments of inertia(MoIs)of 12 triaxial nuclei as extracted ... The covariant density functional theory(CDFT)and five-dimensional collective Hamiltonian(5DCH)are used to analyze the experimental deformation parameters and moments of inertia(MoIs)of 12 triaxial nuclei as extracted by Allmond and Wood[J.M.Allmond and J.L.Wood,Phys.Lett.B 767,226(2017)].We find that the CDFT MoIs are generally smaller than the experimental values but exhibit qualitative consistency with the irrotational flow and experimental data for the relative MoIs,indicating that the intermediate axis exhibites the largest MoI.Additionally,it is found that the pairing interaction collapse could result in nuclei behaving as a rigid-body flow,as exhibited in the^(186-192)Os case.Furthermore,by incorporating enhanced CDFT MoIs(factor of f≈1.55)into the 5DCH,the experimental low-lying energy spectra and deformation parameters are reproduced successfully.Compared with both CDFT and the triaxial rotor model,the 5DCH demonstrates superior agreement with the experimental deformation parameters and low-lying energy spectra,respectively,emphasizing the importance of considering shape fluctuations. 展开更多
关键词 Moment of inertia Trixial nucleus covariant density functional theory Five-dimensional collective Hamiltonian Low-lying energy spectrum
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Human Gait Recognition for Biometrics Application Based on Deep Learning Fusion Assisted Framework
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作者 Ch Avais Hanif Muhammad Ali Mughal +3 位作者 Muhammad Attique Khan Nouf Abdullah Almujally Taerang Kim Jae-Hyuk Cha 《Computers, Materials & Continua》 SCIE EI 2024年第1期357-374,共18页
The demand for a non-contact biometric approach for candidate identification has grown over the past ten years.Based on the most important biometric application,human gait analysis is a significant research topic in c... The demand for a non-contact biometric approach for candidate identification has grown over the past ten years.Based on the most important biometric application,human gait analysis is a significant research topic in computer vision.Researchers have paid a lot of attention to gait recognition,specifically the identification of people based on their walking patterns,due to its potential to correctly identify people far away.Gait recognition systems have been used in a variety of applications,including security,medical examinations,identity management,and access control.These systems require a complex combination of technical,operational,and definitional considerations.The employment of gait recognition techniques and technologies has produced a number of beneficial and well-liked applications.Thiswork proposes a novel deep learning-based framework for human gait classification in video sequences.This framework’smain challenge is improving the accuracy of accuracy gait classification under varying conditions,such as carrying a bag and changing clothes.The proposed method’s first step is selecting two pre-trained deep learningmodels and training fromscratch using deep transfer learning.Next,deepmodels have been trained using static hyperparameters;however,the learning rate is calculated using the particle swarmoptimization(PSO)algorithm.Then,the best features are selected from both trained models using the Harris Hawks controlled Sine-Cosine optimization algorithm.This algorithm chooses the best features,combined in a novel correlation-based fusion technique.Finally,the fused best features are categorized using medium,bi-layer,and tri-layered neural networks.On the publicly accessible dataset known as the CASIA-B dataset,the experimental process of the suggested technique was carried out,and an improved accuracy of 94.14% was achieved.The achieved accuracy of the proposed method is improved by the recent state-of-the-art techniques that show the significance of this work. 展开更多
关键词 Gait recognition covariant factors BIOMETRIC deep learning FUSION feature selection
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