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Study on the flow structure in curved open channels with suspended vegetation using multi relaxation time lattice Boltzmann method

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Journal of Hydrodynamics 2024年第2期36卷 300-315页

作者： He-fang Jing Qiao-ling Zhang Wei-hong Wang Zong-ning Zhang School of Mathematics and Information Science North Minzu UniversityYinchuan750021China School of Civil Engineering North Minzu UniversityYinchuan750021China department of basic {2. Zhengzhou University of Science and TechnologyZhengzhou450064China

Suspended vegetation in rivers,lakes,reservoirs and canals can change flow structure,which will in turn affect the sediment transport and cause the variation of water ecological *** order to study the characteristics of bend flow through suspended vegetation,three-dimensional numerical simulations are carried out by using the multi-relaxation-time lattice Boltzmann method(MRT-LBM).The drag force induced by vegetation is added in the velocity correction in the equilibrium distribution and a hybrid format combined bounce and specular reflection scheme is applied in the solid-fluid *** the validation of this model,six cases are designed to conduct the numerical simulations according to the root depth and the arrangement of *** simulated results show that the suspended vegetation can redistribute the flow structure in curved open *** the arrangement of suspended vegetation,the main flow moves to the side without vegetation,and the distribution of velocity tends to be balanced when vegetation is arranged on the entire cross section,the range of circulating current is reduced from the whole cross section to the local position without vegetation,however,the circulating current can still exist in the curve where the suspended vegetation enters less than half of the water *** addition,it can also be concluded that the suspended vegetation can affect the lateral gradient of flow velocity,and the bed shear stress in the curved channel.

关键词： Multi-relaxation-time lattice Boltzmann method(MRT-LBM) suspended vegetation curved open channel circulating current bed shearstress

Analytical solutions of equatorial geodesic motion in Kerr spacetime

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Chinese Physics C 2024年第4期48卷 222-239页

作者：刘岩孙兵 department of Physics Yantai UniversityYantai 264005China department of basic {2. Beijing University of AgricultureBeijing 102206China CAS Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China

The study of Kerr geodesics has a long history,particularly for those occurring within the equatorial plane,which are generally ***,when compared with the classification introduced by one of the authors[***.D 105,02.075(2.2.)],it becomes apparent that certain classes of geodesics,such as trapped orbits,still lack analytical ***,in this study,we provide explicit analytical solutions for equatorial timelike geodesics in Kerr spacetime,including solutions of trapped orbits,which capture the characteristics of special geodesics,such as the positions and conserved quantities of circular,bound,and deflecting ***,we determine the precise location at which retrograde orbits undergo a transition from counter-rotating to prograde motion due to the strong gravitational effects near a rotating black ***,the trajectory remains prograde for orbits with negative energy despite the negative angular ***,we investigate the intriguing phenomenon of deflecting orbits exhibiting an increased number of revolutions around the black hole as the turning point approaches the turning point of the trapped ***,we find that only prograde marginal deflecting geodesics are capable of traversing through the *** summary,our findings present explicit solutions for equatorial timelike geodesics and offer insights into the dynamics of particle motion in the vicinity of a rotating black hole.

关键词： geodesic motion analytical solutions equatorial plane Kerr spacetime

Low-rank spectral estimation algorithm of learning Markov model

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Frontiers of Mathematics in China 2024年第3期19卷 137-155页

作者： Yongye ZHAO Shujun BI department of basic {2. Guangzhou Maritime UniversityGuangzhou 510725China department of Mathematics South China University of TechnologyGuangzhou 510640China

This paper proposes a low-rank spectral estimation algorithm of learning Markov ***,an approximate projection algorithm for the rank-constrained frequency matrix set is proposed,and thereafter its local Lipschitzian error bound ***,we propose a low-rank spectral estimation algorithm for estimating the state transition frequency matrix and the probability matrix of Markov model by applying the approximate projection algorithm to correct the maximum likelihood estimation of the frequency matrix,and prove that there is only a multiplying constant difference in estimation errors between the low-rank spectral estimation and the maximum likelihood estimation under appropriate ***,numerical comparisons with the prevailing maximum likelihood estimation,spectral estimation,and rank-constrained maxi-mum likelihood estimation show that the low-rank spectral estimation algorithm is effective.

关键词： Markov model low-rank spectral estimation error bound approximate projection

Existence of Multiple Normalized Solutions for Schr?dinger-Choquard Equation with Mixed Nonlinearities

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Acta Mathematicae Applicatae Sinica 2024年

作者： Li-qin TANG Li WANG Jun WANG School of Mathematics Sun Yat-sen University department of basic {2. Hefei University of economics College of Science East China Jiaotong University

This paper considers the existence of multiple normalized solutions of the following SchrodingerChoquard equation where c,ε,μ> 0,N≥3,α∈(0,N),(N+α)/N 2./N 2.,λ∈R is a Lagrange multiplier...

This paper considers the existence of multiple normalized solutions of the following SchrodingerChoquard equation where c,ε,μ> 0,N≥3,α∈(0,N),(N+α)/N 2./N 2.,λ∈R is a Lagrange multiplier which is unknown,Iαis the Riesz potential,k:RN→[0,∞) is a continuous and positive ***εis small enough,we prove that the numbers of normalized solutions are at least the numbers of global maximum points of k by Ekeland:s variational principle and truncated skill.

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Pairing correlation of the kagome-lattice Hubbard model with the nearest-neighbor interaction

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Chinese Physics B 2024年第10期33卷 41-45页

作者： Chen Yang Chao Chen Runyu Ma Ying Liang Tianxing Ma School of Physics and Astronomy Beijing Normal UniversityBeijing 100875China department of basic {2. Naval University of EngineeringWuhan 430033China Key Laboratory of Multiscale Spin Physics(Ministry of Education) Beijing Normal UniversityBeijing 100875China

A recently discovered family of kagome lattice materials,AV_(3)Sb_(5)(A=K,Rb,Cs),has attracted great interest,especiallyin the debate over their dominant superconducting pairing *** explore this issue,we study the superconductingpairing behavior within the kagome-lattice Hubbard model through the constrained path Monte Carlo *** isfound that doping around the Dirac point generates a dominant next-nearest-neighbor-d pairing symmetry driven by on-siteCoulomb interaction ***,when considering the nearest-neighbor interaction V,it may induce nearest-neighbor-ppairing to become the preferred pairing *** results provide useful information to identify the dominant superconductingpairing symmetry in the AV_(3)Sb_(5)family.

关键词： kagome-lattice Hubbard model superconductivity pairing symmetry CPMC

Effect of Eu3+,Bi3+,and Li+ doping on luminescent property of GdNbO4

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Journal of Rare Earths 2024年第1期42卷 66-75页

作者： S.W.Wi Y.S.Lee department of Physics and Integrative Institute of basic Sciences Soongsil University

We investigated the emission properties of Eu3+-doped GdNbO4-based oxide phosphors,aiming at improving the Eu3+emission by codoping of Bi3+and Li+.Eu3+singly doped,Eu3+and Bi3+doubly doped,and Eu3+,Bi3+,and Li+triply doped GdNbO4were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu3+in the singly doped samples are significantly improved by the codoping of Bi3+,mainly due to the energy transfer from Bi3+to Eu3+.The additional codoping of Li+is found to increase the Eu3+emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu3+in GdNbO4does not change significantly with the codoping of Bi3+and Li+.Our results indicate that Li+doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO4phosphors.

关键词： Eu3+ GdNbO4 Codoping of Li+ Photoluminescence Sensitizer Rare earths

Giant and controllable Goos–H?nchen shift of a reflective beam off a hyperbolic metasurface of polar crystals

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Chinese Physics B 2024年第1期 300-307页

作者：薛天李宇博宋浩元王相光张强付淑芳周胜王选章 Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of Educationand School of Physics and Electronic EngineeringHarbin Normal University department of basic {2. Guangzhou Maritime University

We conduct a theoretical analysis of the massive and tunable Goos–H¨anchen(GH) shift on a polar crystal covered with periodical black phosphorus(BP)-patches in the THz range. The surface plasmon phonon polaritons(SPPPs), which are coupled by the surface phonon polaritons(SPh Ps) and surface plasmon polaritons(SPPs), can greatly increase GH *** on the in-plane anisotropy of BP, two typical metasurface models are designed and investigated. An enormous GH shift of about-7565.58 λ0is achieved by adjusting the physical parameters of the BP-patches. In the designed metasurface structure, the maximum sensitivity accompanying large GH shifts can reach about 6.43 × 108λ0/RIU, which is extremely sensitive to the size, carrier density, and layer number of BP. Compared with a traditional surface plasmon resonance sensor, the sensitivity is increased by at least two orders of magnitude. We believe that investigating metasurface-based SPPPs sensors could lead to high-sensitivity biochemical detection applications.

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Engineering the spectra of photon triplets generated from micro/nanofiber

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Chinese Physics B 2024年第3期33卷 408-414页

作者：瞿川郭东琴李笑笑刘振旗赵义张胜海卫正统 The College of basic department Information Engineering UniversityZhengzhou 450000China

Quantum light sources are the core resources for photonics-based quantum information *** investigate the spectral engineering of photon triplets generated by third-order spontaneous parametric down-conversion in micro/*** phase mismatching at one-third pump frequency gives rise to non-degenerate photon triplets,the joint spectral intensity of which has an elliptical locus with a fixed eccentricity of√6/***,we propose a frequency-division scheme to separate non-degenerate photon triplets into three channels with high heralding efficiency for the first *** an appropriate pump wavelength can compensate for the fabrication errors of micro/nanofiber and also generate narrowband,non-degenerate photon triplet sources with a high signal-to-noise ***,the long-period micro/nanofiber grating introduces a new controllable degree of freedom to tailor phase matching,resulting from the periodic oscillation of *** this scheme,the wavelength of photon triplets can be flexibly tuned using quasi-phase *** study the generation of photon triplets from this novel perspective of spectrum engineering,and we believe that this work will accelerate the practical implementation of photon triplets in quantum information processing.

关键词： photon triplets micro/nanofiber spectrum engineering

Higgs-like(pseudo)scalars in AdS_(4),marginal and irrelevant deformations in CFT_(3),and instantons on S^(3)

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Chinese Physics C 2024年第4期48卷 68-81页

作者： M.Naghdi department of Physics Faculty of Basic SciencesUniversity of IlamIlamIran

Employing a 4-form ansatz of 11-dimensional supergravity over a non-dynamical AdS_(4)×S^(7)/Z_(k)background and setting the internal space as an S1 Hopf fibration on CP3,we obtain a consistent ***(pseudo)scalars,in the resulting scalar equations in Euclidean AdS_(4)space,may be considered to arise from(anti)M-branes wrapping around the internal directions in the(Wick-rotated)skew-whiffed M2.brane background(as the resulting theory is for anti-M2.branes),thus realizing the modes after swapping the three fundamental representations 8_(s),8_(c),and 8_(v) of SO(8).Taking the backreaction on the external and internal spaces,we obtain the massless and massive modes,corresponding to exactly marginal and marginally irrelevant deformations on the boundary CFT3,***,we obtain a closed solution for the bulk equation and compute its correction with respect to the background ***,considering the Higgs-like(breathing)mode m^(2.=18,having all supersymmetries as well as parity and scale-invariance broken,solving the associated bulk equation with mathematical methods,specifically the Adomian decomposition method,and analyzing the behavior near the boundary of the solutions,we realize the boundary duals in the SU(4)×U(1)-singlet sectors of the ABJM ***,introducing the new dual deformationΔ_(+)=3,6 operators made of bi-fundamental scalars,fermions,and U(1)gauge fields,we obtain the SO(4)-invariant solutions as small instantons on a three-sphere with the radius at infinity,which correspond to collapsing bulk bubbles leading to big-crunch singularities.

关键词： AdS_(4)/CFT_(3)correspondence scalar equations in AdS_(4) instantons marginal and irrelevant operators (anti)M-branes