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Chinese Physics B 2024年第8期33卷 137-152页

作者：赵会超马雷诺解西阳 department of Mathematics and Physics and Hebei Key Laboratory of Physics and Energy TechnologyNorth China Electric Power UniversityBaoding 071003China

This paper aims to investigate the multi-soliton solutions of the coupled Lakshmanan–Porsezian–Daniel equations with variable coefficients under nonzero boundary *** equations are utilized to model the phenomenon of nonlinear waves propagating simultaneously in non-uniform optical *** analyzing the Lax pair and the Riemann–Hilbert problem,we aim to provide a comprehensive understanding of the dynamics and interactions of solitons of this ***,we study the impacts of group velocity dispersion or the fourth-order dispersion on soliton *** appropriate parameter selections,we observe various nonlinear phenomena,including the disappearance of solitons after interaction and their transformation into breather-like solitons,as well as the propagation of breathers with variable periodicity and interactions between solitons with variable periodicities.

关键词： soliton Riemann-Hilbert problem non-zero boundary conditions coupled Lakshmanan-Porsezian-Daniel equation

Dynamics of fundamental and double-pole breathers and solitons for a nonlinear Schr¨odinger equation with sextic operator under non-zero boundary conditions

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Chinese Physics B 2024年第9期33卷 268-280页

作者： Luyao Zhang Xiyang Xie department of Mathematics and Physics Hebei Key Laboratory of Physics and Energy TechnologyNorth China Electric Power UniversityBaoding 071003China

We study the dynamics of fundamental and double-pole breathers and solitons for the focusing and defocusing nonlinearSchr¨odinger equation with the sextic operator under non-zero boundary conditions. Our analysis mainly focuses onthe dynamical properties of simple- and double-pole solutions. Firstly, through verification, we find that solutions undernon-zero boundary conditions can be transformed into solutions under zero boundary conditions, whether in simple-pole ordouble-pole cases. For the focusing case, in the investigation of simple-pole solutions, temporal periodic breather and thespatial-temporal periodic breather are obtained by modulating parameters. Additionally, in the case of multi-pole solitons,we analyze parallel-state solitons, bound-state solitons, and intersecting solitons, providing a brief analysis of their *** the double-pole case, we observe that the two solitons undergo two interactions, resulting in a distinctive “triangle”crest. Furthermore, for the defocusing case, we briefly consider two situations of simple-pole solutions, obtaining one andtwo dark solitons.

关键词： double-pole solitons double-pole breathers Riemann–Hilbert problem non-zero boundary conditions nonlinear Schr¨odinger equation with sextic operator

Riemann–Hilbert problem for the defocusing Lakshmanan–Porsezian–Daniel equation with fully asymmetric nonzero boundary conditions

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Chinese Physics B 2024年第9期33卷 208-215页

作者： Jianying Ji Xiyang Xie department of Mathematics and Physics and Hebei Key Laboratory of Physics and Energy TechnologyNorth China Electric Power UniversityBaoding 071003China

The Riemann–Hilbert approach is demonstrated to investigate the defocusing Lakshmanan–Porsezian–Daniel equation under fully asymmetric nonzero boundary *** contrast to the symmetry case,this paper focuses on the branch points related to the scattering problem rather than using the Riemann *** the direct problem,we analyze the Jost solution of lax pairs and some properties of scattering matrix,including two kinds of *** inverse problem at branch points can be presented,corresponding to the associated Riemann–***,we investigate the time evolution problem and estimate the value of solving the solutions by Jost *** the inverse problem,we construct it as a Riemann–Hilbert problem and formulate the reconstruction formula for the defocusing Lakshmanan–Porsezian–Daniel *** solutions of the Riemann–Hilbert problem can be constructed by estimating the ***,we work out the solutions under fully asymmetric nonzero boundary conditions precisely via utilizing the Sokhotski–Plemelj formula and the square of the negative column transformation with the assistance of Riemann *** results are valuable for understanding physical phenomena and developing further applications of optical problems.

关键词： Riemann–Hilbert problem defocusing Lakshmanan–Porsezian–Daniel equation inverse scattering transform asymmetric nonzero boundary conditions

Nuclear charge radius predictions by kernel ridge regression with odd-even effects

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Nuclear Science and Techniques 2024年第2期35卷 94-102页

作者： Lu Tang Zhen-Hua Zhang Mathematics and Physics department North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and energy Technology North China Electric Power UniversityBaoding 071000China

The extended kernel ridge regression(EKRR)method with odd-even effects was adopted to improve the description of the nuclear charge radius using five commonly used nuclear *** are:(i)the isospin-dependent A^(1∕3) formula,(ii)relativistic continuum Hartree-Bogoliubov(RCHB)theory,(iii)Hartree-Fock-Bogoliubov(HFB)model HFB25,(iv)the Weizsacker-Skyrme(WS)model WS*,and(v)HFB25**** the last two models,the charge radii were calculated using a five-parameter formula with the nuclear shell corrections and deformations obtained from the WS and HFB25 models,*** each model,the resultant root-mean-square deviation for the 1014 nuclei with proton number Z≥8 can be significantly reduced to 0.009-0.013 fm after considering the modification with the EKRR *** best among them was the RCHB model,with a root-mean-square deviation of 0.0092 *** extrapolation abilities of the KRR and EKRR methods for the neutron-rich region were examined,and it was found that after considering the odd-even effects,the extrapolation power was improved compared with that of the original KRR *** strong odd-even staggering of nuclear charge radii of Ca and Cu isotopes and the abrupt kinks across the neutron N=126 and 82 shell closures were also calculated and could be reproduced quite well by calculations using the EKRR method.

关键词： Nuclear charge radius Machine learning Kernel ridge regression method

Does the Hartman effect exist in triangular barriers

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Chinese Physics B 2024年第3期33卷 214-230页

作者：李青玲郑爽肖智 department of Mathematics and Physics North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and energy Technology North China Electric Power UniversityBaoding 071000Chin

We study the phase,Larmor and dwell times of a particle scattered off triangular barriers(TBs).It is interesting that the dependences of dwell,reflective phase and Larmor times on the wave number,barrier width and height for a pair of mirror-symmetric(MS)exact triangular barriers(ETBs)are quite different,as the two ETBs have quite distinct scattering *** comparison,the dependence of the transmitted phase or Larmor times is exactly the same,since the transmitted amplitudes are the same for a pair of MS *** further study the Hartman effect by defining the phase and Larmor velocities associated with the phase and Larmor *** find no barrier width saturation effect for the transmitted and reflected *** is indicated by the fact that all the velocities approach finite constants that are much smaller than the speed of light in vacuum for TBs with positive-slope impact *** for ETBs with vertical left edges,the naive velocities seem to also indicate the absence of the Hartman *** are quite distinct from rectangular barriers and may shed new light on the clarification of the tunneling time issues.

关键词： triangular barrier Hartman effect

Robustness of the octupole collectivity in 144Ba within the cranking covariant density functional theory in 3D lattice

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Nuclear Science and Techniques 2024年第8期35卷 124-131页

作者： Ze‑Kai Li Yuan‑Yuan Wang Mathematics and Physics department North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and energy Technology North China Electric Power UniversityBaoding 071000China

The octupole deformation and collectivity in octupole double-magic nucleus 144Ba are investigated using the Cranking covariant density functional theory in a three-dimensional lattice *** reduced B(E3)transition probability is implemented for the first time in semiclassical approximation based on the microscopically calculated electric octupole *** available data,including the I-ωrelation and electric transitional probabilities B(E2)and B(E3)are well ***,it is shown that the ground state of 144Ba exhibits axial octupole and quadrupole deformations that persist up to high spins(I≈24h).

关键词： Octupole collectivity Cranking covariant density functional theory Rotational spectrum electric transitional probabilities

Numerical Investigation on Characteristics of Supercritical CO_(2)Heat Transfer in Vertical Circular Tubes with Circumferentially Half-Side Heating

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Journal of Thermal Science 2024年第5期33卷 1744-1756页

作者： ZHANG Yan ZHANG Xinyi YAN Chenshuai WU Wenhua GAO Erman School of energy and Power Engineering Northeast Electric Power UniversityJilin 132012China

The design of heat exchangers in the advanced supercritical power conversion system cannot be separated from the study of heat transfer ***-side heating mode is often encountered for solar receiver and supercritical ***,the characteristics of supercritical CO_(2)(sCO_(2))convection heat transfer in vertical tubes with circumferentially half-side heating was numerically investigated through the SST k-ωturbulent model which matches well with the experimental ***,heat transfer between sCO_(2)upflow and downflow was *** to film boiling heat transfer at subcritical pressure,numerical results were processed according to the supercritical pseudo-phase transition hypothesis,with liquid-like phase in the tube core region and vapor-like film in the region near the heated tube *** structure of two layers was demarcated by pseudo-critical temperature T_(pc).Therefore,sCO_(2)heat transfer was assessed according to double thermal resistances caused by vapor-like film near the wall and core liquid-like *** findings suggest that wall temperature for upflow is higher than that for downflow,which is attributed to larger thermal resistance in the fluid domain for upflow than that for *** difference guarantees the excellent heat transfer performance for downflow than *** is also further concluded that the formation of vapor-like film near the wall due to pseudo-phase transition plays a key role in dominating wall temperature and inducing heat transfer deterioration in half-side heating *** present contribution is significant to the design of supercritical heat exchanger under half-side heating mode.

关键词： supercritical CO_(2) pseudo-phase transition half-side heating thermal resistance flow direction

Isotopic dependence of the yield ratios of light fragments from different projectiles and their unified neutron skin thicknesses

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Nuclear Science and Techniques 2024年第3期35卷 228-236页

作者： Ting-Zhi Yan Shan Li School of energy and Power Engineering Northeast Electric Power UniversityJilin 132012China

The yield ratios of neutron-proton(R(n/p))and^(3)H-^(3)He(R(^(3)H∕^(3)He))with reduced rapidity from 0 to 0.5 were simulated at 50 MeV/u even-even ^(36−56)Ca+^(40)Ca,even-even ^(48−78)Ni+^(58)Ni,and ^(100−139)Sn(every third isotopes)+112 Sn for full reduced impact parameters using the isospin-dependent quantum molecular dynamics(IQMD)*** neutron and proton density distributions and root-mean-square radii of the reaction systems were obtained using the Skyrme-Hartree-Fock model,which was used for the phase space initialization of the projectile and target in *** defined the unified neutron skin thickness asΔRnp=^(1∕2) n−^(1∕2)p,which was negative for neutron-deficient *** unifiedΔRnp values for nuclei with the same relative neutron excess from different isotopic chains were nearly equal,except for extreme neutron-rich isotopes,which is a type of scaling *** yield ratios of the three isotopic chain-induced reactions,which depended on the reduced impact parameter and unified neutron skin thickness,were *** results showed that both R(n/p)and R(^(3)H∕^(3)He)decreased with a reduced impact parameter for extreme neutron-deficient isotopes;however,they increased with reduced impact parameters for extreme neutron-rich isotopes,and increased with theΔRnp of the projectiles for all reduced impact *** addition,a scaling phenomenon was observed betweenΔR np and the yield ratios in peripheral colli-sions from different isotopic chain projectiles(except for extreme neutron-rich isotopes).Thus,R(n/p)and R(^(3)H∕^(3)He)from peripheral collisions were suggested as experimental probes for extracting the neutron or proton skin thicknesses of non-extreme neutron-rich nuclei from different isotopic chains.

关键词： Exotic nuclei Unified neutron skin thickness Yield ratios IQMD

Promoted hydrogenation of CO2 to methanol over single-atom Cu sites with Na+-decorated microenvironment

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National Science Review 2024年第6期11卷 264-272页

作者： Li-Li Ling Xinyu Guan Xiaoshuo Liu Xiao-Mei Lei Zhongyuan Lin Hai-Long Jiang Hefei National Research Center for Physical Sciences at the Microscale Department of Chemistry University of Science and Technology of China School of energy and Power Engineering North China Electric Power University School of energy and Environment Southeast University

Although single-atom Cu sites exhibit high efficiency in CO2hydrogenation to methanol,they are prone to forming Cu nanoparticles due to reduction and aggregation under reaction conditions,especially at high ***,single-atom Cu sites stabilized by adjacent Na+ions have been successfully constructed within a metal-organic framework（MOF）-based catalyst,namely *** is found that the electrostatic interaction between the Na+and Hδ-species plays a pivotal role in upholding the atomic dispersion of Cu in MOF-808-NaCu during CO2hydrogenation,even at temperatures of up to 275℃.This exceptional stabilization effect endows the catalyst with excellent activity(306 g·kgcat-1·h-1),high selectivity to methanol（93%） and long-term stability at elevated reaction temperatures,far surpassing the counterpart in the absence of Na+（denoted as MOF-808-Cu）.This work develops an effective strategy for the fabrication of stable single-atom sites for advanced catalysis by creating an alkali-decorated microenvironment in close proximity.

关键词： single-atom sites metal–organic framework CO2 hydrogenation heterogeneous catalysis alkali-metal decoration

Assessment and Enhancement of FRC of Power Systems Considering Thermal Power Dynamic Conditions

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CSEE Journal of Power and energy Systems 2024年第4期10卷 1371-1383页

作者： Feng Hong Yalei Pang Weiming Ji Lu Liang Fang Fang Junhong Hao Jizhen Liu State Key Laboratory of Alternate electric Power System with Renewable energy Sources and School of Control and Computer Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Alternate electric Power System with Renewable energy Sources School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing 102206China

Frequency stability and security have been a vital challenge as large-scale renewable energy is integrated into power *** contrast,the proportion of traditional thermal power units decreases during the decarbonization transformation process,resulting in poor frequency *** paper aims to explore the potential of frequency regulation support,dynamic assessment,and capacity promotion of thermal power plants in the transition *** the dynamic characteristics of the main steam working fluid under different working conditions,a nonlinear observer is constructed by extracting the main steam pressure and valve opening degree *** real-time frequency modulation capacity of thermal power units can provide a dynamic state for the power grid.A dynamic adaptive modification for primary frequency control(PFC)of power systems,including wind power and thermal power,is proposed and *** power dynamic allocation factor is adaptively optimized by predicting the speed droop ratio,and the frequency modulation capability of the system is improved by more than 11%under extreme ***,through the Monte Carlo simulation of unit states of the system under various working conditions,the promotion of the frequency regulation capacity with high wind power penetration(WPP)is verified.

关键词： Dynamic evaluation frequency regulation power system predictive modeling wind penetration