作者机构：
[Fan, Chenzhou; Wang, Tianlin] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Xu, Feng; Xu, F; Guo, Changqing] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
通讯机构：
[Xu, F ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
关键词：
Foundation excitation;Gap constraint;Fluid-conveying pipe;Impact vibration
摘要：
In practical engineering, the unilateral gap constraint impact vibration in fluid-conveying pipes is a critical concern, often arising from constraint loosening or the presence of barriers around the pipe. These factors can significantly affect the service life and safety reliability of the pipes. A tension and compression anisotropy spring with rapidly increasing restoring force in compression but almost zero restoring force in tension is proposed to simulate the unilateral gap constraint, model a fluid-conveying pipe with a Pfluger column. Its reliability is also verified based on the bifurcation phase diagram comparison between the small and large stiffness conditions. Subsequently, we establish a vibration mechanics analysis model for the cantilever fluid-conveying pipe under foundation excitation to assess the effects of basic excitation frequency, fluid velocity, distributed follower force, position coordinate of unilateral gap constraint, and the viscoelastic coefficient on the impact vibration stability of the fluid-conveying pipe. Our findings reveal that when the period-doubling bifurcation sequence is interrupted by Bare-grazing bifurcation, the system directly transitions into chaotic vibration or induces a new period-doubling bifurcation sequence, followed by re-entry into chaotic vibration. These results provide valuable insights into the intricate dynamics of fluid-conveying pipes under foundation excitation, offering a deeper understanding of the impact of various parameters on the pipe's vibration.
In practical engineering, the unilateral gap constraint impact vibration in fluid-conveying pipes is a critical concern, often arising from constraint loosening or the presence of barriers around the pipe. These factors can significantly affect the service life and safety reliability of the pipes. A tension and compression anisotropy spring with rapidly increasing restoring force in compression but almost zero restoring force in tension is proposed to simulate the unilateral gap constraint, model a fluid-conveying pipe with a Pfluger column. Its reliability is also verified based on the bifurcation phase diagram comparison between the small and large stiffness conditions. Subsequently, we establish a vibration mechanics analysis model for the cantilever fluid-conveying pipe under foundation excitation to assess the effects of basic excitation frequency, fluid velocity, distributed follower force, position coordinate of unilateral gap constraint, and the viscoelastic coefficient on the impact vibration stability of the fluid-conveying pipe. Our findings reveal that when the period-doubling bifurcation sequence is interrupted by Bare-grazing bifurcation, the system directly transitions into chaotic vibration or induces a new period-doubling bifurcation sequence, followed by re-entry into chaotic vibration. These results provide valuable insights into the intricate dynamics of fluid-conveying pipes under foundation excitation, offering a deeper understanding of the impact of various parameters on the pipe's vibration.
摘要：
In this paper, we give six classes of permutation polynomials of the form $ (x^{2^m}+x+\delta)^s+ax $ over $ \mathbb{F}_{2^{2m}} $ and six classes of permutation polynomials of the form $ (x^{p^m}-x+\delta)^s+ax^{p^m}+a^{p^m}x $ over $ \mathbb{F}_{p^{2m}} $ ($ p $ being an odd prime), respectively. In addition, we also investigate permutation polynomials obtained from piecewise functions. Consequently, we find some complete permutation polynomials.
作者机构：
[Lin, Wenbin; Jiang, Chunhua; Yang, Bo; Lin, WB] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Yang, Bo] Chinese Acad Sci, Purple Mt Observ, Nanjing 210023, Peoples R China.
通讯机构：
[Lin, WB ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
关键词：
Black holes;Regular Simpson-Visser black-bounce spacetime;Periastron advance
摘要：
In this paper, we present the second post-Newtonian solution for the quasi-Keplerian motion of a test particle in the regular Simpson-Visser black-bounce spacetime which has a bounce parameter $a$. The obtained solution is formulated in terms of the orbital energy, angular momentum, and the bounce parameter of the black hole. We explicitly analyze the leading effects of the bounce parameter, which has dimensions of length, on the test particle's orbit, including the periastron advance and orbital period. Then, we apply this model to the precessing motion of OJ 287 and determine the upper limits of the dimensionless bounce parameter as $a/m =3.45\pm 0.01$, where $m$ is the mass of the regular black hole. Compared with the bound given by the periastron advance of star S2, our bound on $a/m$ is reduced by one order of magnitude, although our upper limit of $a$ still needs further improvement.
作者机构：
[Lin, Wenbin; Lin, WB] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Lin, Wenbin; Lin, WB] Southwest Jiaotong Univ, Sch Phys Sci & Technol, Chengdu 610031, Peoples R China.
通讯机构：
[Lin, WB ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;Southwest Jiaotong Univ, Sch Phys Sci & Technol, Chengdu 610031, Peoples R China.
关键词：
post-Newtonian approximation;gravitomagnetic field;second gravitational potential;spherically-symmetric system
摘要：
We prove that the post-Newtonian time-dependent metric of the self-gravitating and collapsing infinitely-thin spherical shell does satisfy Einstein field equations to the corresponding order. Meanwhile, the leading-order components of the thin spherical shell's energy-momentum tensor are recovered.
摘要：
This paper presents a Respiratory Syncytial Virus (RSV) epidemic model for a continuous human population of super-spreading infected individuals. The model uses a generalized fractal-fractional derivative with the Mittag-Leffler function to analyze transmission, considering different infection stages, and demonstrates the effectiveness of certain individuals as viral spreaders. Using linear growth and Lipschitz requirements, the study determines the existence, uniqueness, positiveness, and boundedness of a proposed fractional-order system in order to assess its viability. The global stability of equilibrium points is verified by the Lyapunov function, and the effects of the model's parameters are investigated through sensitivity analysis. To comprehend the model's behavior and create preventative measures for infected people, a numerical simulation of its activity is also carried out. By offering a more realistic depiction of virus behavior at various dimensions and population effects, the fractal-fractional model enhances comprehension and forecasts. The results highlight the importance of fractional order and its fitting function in the model by demonstrating how input parameters affect the dynamic behavior of RSV infection. Such an investigation will aid in understanding the behavior of the RSV and develop prevention measures for infected individuals.
作者机构：
[Chen, Guohao; Wang, Zhiqiao] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Zhang, XY; Zhang, Xiaoyang] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
通讯机构：
[Zhang, XY ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
关键词：
thermal effect;locally resonant;finite element method;tunable bandgap;defect states;waveguide
摘要：
Based on the finite element method, the modulation of the bending wave bandgap and bending waveguide of locally resonant phononic crystal (PnC) plates via a thermal environment is investigated. First, the finite element model of the PnC subjected to a thermal field is introduced; then, the modulation behavior of the bending wave bandgap of the PnC under thermal flux is illustrated; finally, the tunable waveguide of the bending waveguide of the PnC supercell is proposed to be realized by setting up a local heat source. The results show that the injected heat flux causes the PnC unit cell band structure to move toward the low-frequency region while the relative bandgap width increases. The linear defect state of the PnC supercell structure is realized by introducing a local heat source, and a new band is added to the bending wave bandgap of the original supercell. The transmission loss of the bending wave is significantly higher than that of the bending wave bandgap of the supercell in the frequency interval of the linear defect of the supercell, and the frequency response vibrational modes of the supercell structure validate the feasibility of the thermally controlled bending waveguide. This method provides a flexible and efficient control strategy for the frequency tuning of the bending wave bandgap and waveguide.
期刊：
Nuclear Engineering and Design,2025年433:113872 ISSN：0029-5493
通讯作者：
Liu, HL
作者机构：
[Liu, Hongliang; Ouyang, Zigen; Liu, HL; Liu, Wangheng] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Zeng, Wenjie] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Liu, Hua] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Liu, HL ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
关键词：
Adaptive learning observer;Radial basis function neural networks;Fixed-time fault-tolerant control;Control rod drive mechanism faults;Load following for modular high-temperature;gas-cooled reactor
摘要：
Load following of the Modular High-Temperature Gas-Cooled Reactor (MHTGR) under Control Rod Drive Mechanism (CRDM) faults and disturbances remains a major challenge. This paper focuses on proposing a fixed-time fault-tolerant control method for this issue without considering the sensitivities associated with parameter setting. Firstly, to reconstruct some unmeasurable states of the MHTGR and the values of CRDM faults, an adaptive learning observer is established. Based on the learning characteristic of Radial Basis Function Neural Networks (RBFNN), the lumped uncertainties can be approximated. And then a fixed-time fault-tolerant controller is developed to ensure that the actual load output of the MHTGR actually tracks the expected output power within a fixed time, which can be determined through the system and controller parameters. Finally, simulations under two operational conditions demonstrate the control method is effective and feasible to the MHTGR system under disturbance and CRDM faults.
Load following of the Modular High-Temperature Gas-Cooled Reactor (MHTGR) under Control Rod Drive Mechanism (CRDM) faults and disturbances remains a major challenge. This paper focuses on proposing a fixed-time fault-tolerant control method for this issue without considering the sensitivities associated with parameter setting. Firstly, to reconstruct some unmeasurable states of the MHTGR and the values of CRDM faults, an adaptive learning observer is established. Based on the learning characteristic of Radial Basis Function Neural Networks (RBFNN), the lumped uncertainties can be approximated. And then a fixed-time fault-tolerant controller is developed to ensure that the actual load output of the MHTGR actually tracks the expected output power within a fixed time, which can be determined through the system and controller parameters. Finally, simulations under two operational conditions demonstrate the control method is effective and feasible to the MHTGR system under disturbance and CRDM faults.
作者机构：
[Lin, Wenbin; Li, Jie] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Lv, Hongkui; Huang, Jiajun] Chinese Acad Sci, Inst High Energy Phys, Key Lab Particle Astrophys, Beijing 100049, Peoples R China.;[Lv, Hongkui] TIANFU Cosm Ray Res Ctr, Chengdu, Sichuan, Peoples R China.;[Lin, Wenbin; Liu, Yang] Univ South China, Sch Comp Sci, Hengyang 421001, Peoples R China.;[Huang, Jiajun] Univ Chinese Acad Sci, Beijing, Peoples R China.
通讯机构：
[Li, J ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
摘要：
Abstract Identifying gamma rays and rejecting the background of cosmic-ray hadrons are crucial for very-high-energy gamma-ray observations and relevant scientific research. Based on the simulated data from the square kilometer array (KM2A) of LHAASO, eight high-level features were extracted for the gamma/hadron classification. Machine learning (ML) models, including logistic regression, support vector machines, decision trees, random forests, XGBoost, CatBoost, and deep neural networks (DNN) were constructed and trained using data sets of four energy bands ranging from 1012 to 1016 eV, and finally fused using the stacking ensemble algorithm. To comprehensively assess the classification ability of each model, the accuracy, F1 score, precision, recall, and area under the curve value of the receiver operating characteristic curve were used. The results show that the ML methods have a significant improvement on particle classification in LHAASO-KM2A, particularly in the low-energy range. Among these methods, XGBoost, CatBoost, and DNN demonstrate stronger classification capabilities than decision trees and random forests, while the fusion model exhibits the best discriminatory ability. The ML methods provide a useful and alternative method for gamma/hadron identification. The codes used in this paper are available at Zenodo at doi:10.5281/zenodo.13623261.
作者机构：
[Wang, Hongyong] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Ou, Chunhua; Ou, CH] Mem Univ Newfoundland, Dept Math & Stat, St John, NF A1C 5S7, Canada.
通讯机构：
[Ou, CH ] M;Mem Univ Newfoundland, Dept Math & Stat, St John, NF A1C 5S7, Canada.
关键词：
Lotka-Volterra competition system;gap formation;forced pulsating waves;spreading dynamics;shifting media
摘要：
We study the propagation dynamics of a Lotka-Volterra competition system in which one growth rate behaves like a monotonically decreasing wave profile that shifts with a given speed and is also periodic in the first spatial variable, while the other growth rate behaves similarly, except that its profile is monotonically increasing with respect to the shifting variable. Furthermore, both growth functions are assumed to be sign-changed, which implies that the environments in which the species live switch spatially from 'good' regions (suitable for survival) to 'bad' regions (not suitable for survival) and vice versa. We reveal that the model admits a forced pulsating wave only when the forced speed lies within a finite interval (c & lowast;,c(& lowast;)) that contains zero. Biologically, this corresponds to the formation of a shifting cline. Moreover, we find that c(& lowast;)<0 and c(& lowast;)>0 can be calculated in terms of the Fisher-KPP speeds related to the linearized equations of each species. By applying a sliding technique, we show that the forced pulsating wave is unique. We also prove that the forced pulsating wave is Lyapunov-stable. Finally, the spreading dynamics of spatial gap formation in the two species are also investigated when the forced wave speed is either less than c(& lowast;) or greater that c(& lowast;). We employ a novel approach to demonstrate how the species invade in response to a shifting environment.
摘要：
The nonlinear vibrations developing in sheets and strips during rolling are of practical technological importance and of theoretical interest. However, the existing numerical methods adopted in research are plagued by problems such as computational inefficiency, difficulty in dealing with bifurcations, slow convergence and frequency cancellations. This study develops an analytical method for solving the problem of rolled strip quasi-periodic motions in the resonant state. First, the conventional incremental harmonic balance method is used to analyze the periodic response of a strip. Its nonlinear frequency response curve is obtained and the type of bifurcation along with its location is determined. Second, the quasi-periodic motion spectrum of the strip is characterized utilizing the fact that the adjacent frequencies in the side bands are equidistant from each other and contain two incommensurable fundamental frequencies. The fundamental frequencies of the strip quasi-periodic motion, as well as all of the frequency components and their corresponding amplitudes, are accurately resolved, especially the quasi-periodic motion response near the critical point. Finally, several numerical examples of the nonlinear vibrations exhibited by the rolled strip in the presence of internal resonance are investigated in depth to validate the proposed method performance and accuracy. These examples are concerned with the internal resonance with an even inherent frequency ratio of 1:6, which may arise during the rolling process, but remains relatively unexplored. The newly proposed method will add to the arsenal of available analytical techniques, expanding the capabilities of both researchers and practicing engineers.
摘要：
Cu-based self-lubricating composites have excellent mechanical properties and enhanced friction characteristics, rendering them ideal for aerospace wear parts. However, the significant mismatch in coefficients of thermal expansion (CTE) between them and counterparts, typically steel, would limit their widespread application. To address this issue, Ni50Fe powders with a low CTE are incorporated into Cu15Ni8Sn-MoS 2 composites via mixing and hot-pressed sintering, resulting in Cu15Ni8Sn-Ni50Fe-MoS 2 composites. The addition of Ni50Fe significantly reduces the CTE of the composites. When added in moderation, Ni50Fe can enhance the mechanical properties and wear resistance, despite a slight degradation in lubricity. The variations in mechanical and friction properties of the composites are attributed to the reaction of Cu and Fe with MoS 2 and the change of matrix composition. The composite containing 40 vol% Ni50Fe (N40) has the best comprehensive performance. Compared to the Cu15Ni8Sn-MoS 2 composite, the CTE of N40 is reduced by 13.7%, along with increases in hardness (5.2%), transverse rupture strength (19.1%), radial crushing strength (11.3%), and a reduction in wear rate (8.8%), although its friction coefficient increases by 15.4%.
摘要：
Acoustic phonons have long been believed to dominate the lattice thermal conductivity ( κ l ) and the contribution of optical phonons can be neglected in crystal structures. KCaBi, as a high-throughput screening semiconductor with ultralow κ l [J. Am. Chem. Soc. 144, 4448 (2022)], has been demonstrated that the contribution of optical phonons plays an important role in thermal transport. In this work, by solving the Boltzmann transport equation, it is found that the κ l of KCaBi is 2.2 at 300K, with acoustic phonons dominating the z-direction κ l and optical phonons contributing around 50% to the x-direction κ l under the four-phonon picture. The uncommon contribution of optical phonons also manifests the possibility of tuning the κ l anisotropy based on optical phonons. Following this line of thinking, it is found that applying tensile strain can cause a more pronounced decrease of acoustic phonon contribution than that of optical counterpart due to the highly dispersive optical branches, thus enhancing the anisotropic ratio of κ l . Moreover, the microscopic mechanism is elucidated by analyzing the phonon dispersion relation, phonon mode-wise contribution and phonon scattering rates. Our study could provide appealing alternatives for the regulation of phonon transport from the viewpoint of optical phonons.
Acoustic phonons have long been believed to dominate the lattice thermal conductivity ( κ l ) and the contribution of optical phonons can be neglected in crystal structures. KCaBi, as a high-throughput screening semiconductor with ultralow κ l [J. Am. Chem. Soc. 144, 4448 (2022)], has been demonstrated that the contribution of optical phonons plays an important role in thermal transport. In this work, by solving the Boltzmann transport equation, it is found that the κ l of KCaBi is 2.2 at 300K, with acoustic phonons dominating the z-direction κ l and optical phonons contributing around 50% to the x-direction κ l under the four-phonon picture. The uncommon contribution of optical phonons also manifests the possibility of tuning the κ l anisotropy based on optical phonons. Following this line of thinking, it is found that applying tensile strain can cause a more pronounced decrease of acoustic phonon contribution than that of optical counterpart due to the highly dispersive optical branches, thus enhancing the anisotropic ratio of κ l . Moreover, the microscopic mechanism is elucidated by analyzing the phonon dispersion relation, phonon mode-wise contribution and phonon scattering rates. Our study could provide appealing alternatives for the regulation of phonon transport from the viewpoint of optical phonons.
期刊：
Annals of Nuclear Energy,2025年212:111033 ISSN：0306-4549
通讯作者：
Liu, YQ
作者机构：
[Liu, YQ; Hu, Qian; Zheng, Yongle; Liu, Yanqi] Univ South China, Sch Math & Phys, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Liu, YQ ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Hunan, Peoples R China.
关键词：
NPPs;Organizational performance;PSF;Interval Hierarchical Analysis (IHA);Optimization study of PSF weighting
摘要：
The organizational performance of main control room (MCR) operators is crucial in digital nuclear power plants (NPPs). A comprehensive study determined the weights of performance-shaping factors (PSFs) influencing operators’ organizational performance. Firstly, a questionnaire survey was conducted, and an interval judgment matrix was innovatively established based on the expectation and standard deviation of statistical data acquired. Next, interval hierarchical analysis (IHA) was employed to derive reasonable intervals for each PSF weight. Finally, a hierarchical interval weighting optimization mathematical model was established for high-precision weighting calculation. This method offers a significant reference for optimizing the PSF weighting process. The approach presented in this paper is highly adaptable and provides new technical and theoretical support for the study of weighting theory.
The organizational performance of main control room (MCR) operators is crucial in digital nuclear power plants (NPPs). A comprehensive study determined the weights of performance-shaping factors (PSFs) influencing operators’ organizational performance. Firstly, a questionnaire survey was conducted, and an interval judgment matrix was innovatively established based on the expectation and standard deviation of statistical data acquired. Next, interval hierarchical analysis (IHA) was employed to derive reasonable intervals for each PSF weight. Finally, a hierarchical interval weighting optimization mathematical model was established for high-precision weighting calculation. This method offers a significant reference for optimizing the PSF weighting process. The approach presented in this paper is highly adaptable and provides new technical and theoretical support for the study of weighting theory.
作者机构：
[Lin, Wenbin; He, Guansheng; He, GS; Yang, Bo; Wang, Xuan] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Lin, Wenbin] Southwest Jiaotong Univ, Sch Phys Sci & Technol, Chengdu 610031, Peoples R China.;[He, Guansheng; He, GS; Yang, Bo] Chinese Acad Sci, Purple Mt Observ, Nanjing 210023, Peoples R China.
通讯机构：
[He, GS ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;Chinese Acad Sci, Purple Mt Observ, Nanjing 210023, Peoples R China.
关键词：
black holes;exact metric;gravitational lens
摘要：
Abstract The gravitational deflection of light signals restricted in the polar-axis plane of a moving Kerr-Newman (KN) black hole with a constant velocity along the polar axis is studied within the second post-Minkowskian (PM) approximation. For this purpose, the Lorentz boosting technique is adopted to obtain the exact metric of a moving KN black hole with an arbitrary constant velocity in Kerr-Schild coordinates for the first time. Based on the weak field limit of the exact metric, we then derive the equations of motion of test particles constrained in the polar-axis plane of a moving KN source whose velocity is along the polar axis and collinear with its angular momentum. An iterative technique is utilized subsequently in the calculations of the null deflection angle up to the 2PM order caused by the moving lens, and this deflection angle is found to be spin-independent. Finally, we discuss the influence of the motion of the lens on the gravitational deflection and estimate the possibility to detect this kinematical effect. Our work might be helpful for future astronomical observations.
作者机构：
[Wu, Xiao-Jun] China Jiliang Univ, Coll Modern Sci & Technol, Yiwu 322000, Zhejiang, Peoples R China.;[Lin, Wenbin; Li, Jie; Wu, Xiao-Jun] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Wu, Xiao-Jun] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Luo, Yan; Yuan, Ye-Fei] Univ Sci & Technol China, Sch Astron & Space Sci, Hefei 230026, Peoples R China.;[Luo, Yan; Yuan, Ye-Fei] Univ Sci & Technol China, CAS Key Lab Res Galaxies & Cosmol, Hefei 230026, Peoples R China.
通讯机构：
[Yuan, YF ] U;Univ Sci & Technol China, Sch Astron & Space Sci, Hefei 230026, Peoples R China.;Univ Sci & Technol China, CAS Key Lab Res Galaxies & Cosmol, Hefei 230026, Peoples R China.
摘要：
Abstract In the vicinity of galactic nuclei, stars orbiting supermassive black hole (SMBH) binaries can undergo tidal disruption events (TDEs) due to the Lidov–Kozai mechanism and three-body interactions. While numerical simulations have incorporated post-Newtonian (PN) corrections up to 2.5PN order, they have not accounted for the 1PN cross-term effects among the three bodies. In this study, we employ N-body simulations to investigate the impact of the 1PN cross terms on the orbits of stars around an intermediate-mass black hole (IMBH) perturbed by an outer SMBH. Our findings indicate that while the 1PN cross terms do not substantially affect the fractions of stellar outcomes, they can cause considerable variations in the orbits of stars around IMBH–SMBH binaries. Specifically, we find that the inclusion of the 1PN cross terms can lead to more concentrated distributions of semimajor axes. Furthermore, we observe heavy tails in the distributions of temporal shifts in TDEs when these cross terms are included, with the maximum change reaching about 106 yr, approaching the maximum integration time of this study. This investigation underscores the critical importance of incorporating the 1PN cross terms to ensure accuracy in comprehensive simulations of multibody systems in galactic nuclei. Notably, for stars partially disrupted by an SMBH binary, omitting these cross terms could result in erroneous predictions.
作者机构：
[Lin, Wenbin; Liu, Yang] Univ South China, Sch Comp Sci, Hengyang 421001, Peoples R China.;[Lin, Wenbin; Xu, Zhenghua; Li, Jie; Gao, Linqing] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Zhang, Haotong] Chinese Acad Sci, Natl Astron Observ, Beijing 100101, Peoples R China.;[Wang, Yu] Sapienza Univ Roma, ICRA & Dipartimento Fis, Piazzale Aldo Moro 5, I-00185 Rome, Italy.;[Lin, Wenbin; Wang, Yu] ICRANet, Pzza Repubbl 10, I-65122 Pescara, Italy.
通讯机构：
[Xu, ZH ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
摘要：
Abstract Quasar absorption lines are a powerful tool for studying the Universe, enabling us to probe distant gas, dust, and galaxy formation and evolution. However, detecting these lines, particularly Ca ii absorption lines, is a time-consuming and laborious process. Existing deep learning methods are prone to false positives and still require extensive manual verification and parameter measurement. This work presents three multitask convolutional neural network models and identifies the ResNet-CBAM model, which incorporates residual learning and an attention mechanism as the most effective. The results show that the ResNet-CBAM model achieves an accuracy of 99.7% in detecting Ca ii absorbers and excels in predicting critical parameters such as equivalent width and full width at half-maximum, with average correlation coefficients of 0.98 and 0.85, respectively. Furthermore, its remarkable generalization ability significantly improves detection precision on unseen data, rising from 20.3% of the cutting-edge model to 92.6%. In addition, with our numerous optimizations, our method can directly search for nonnormalized data, still achieving an accuracy of 98.6%. This translates to a dramatic reduction in manual inspection workload, paving the way for efficient and automated Ca ii absorber identification. In real-world applications on the Sloan Digital Sky Survey DR7 and DR12, our model successfully rediscovered 321 known Ca ii absorbers while identifying potential candidates in an additional 381 spectra. The codes used in this paper are available on Zenodo at doi:10.5281/zenodo.13953656.
摘要：
INTRODUCTION: The interaction between endothelial cells can regulate hemostasis, vasodilation, as well as immune and inflammatory responses. Excessive loading on the endothelial cells leads to endothelial damage and endothelial barrier dysfunction. Understandingandmasteringthe dynamic nature of cell-cell rupture plays a crucial role in exploring the practical applications related to tumor destruction, vascular remodeling, and drug delivery byemploying cavitation-induced damage tosoft tissues. METHODS: To investigate the damage mechanisms of endothelial cellular networks under ultrasound cavitation, we developed a model of junction rupture in cellular networks based on the assumption that the process of intercellular rupture is irreversible when ultrasound-mediated forces exceed the damage threshold, whereas intercellular junctions have reversible behavior before rupture. Simulations using the strain accumulation method show that stress and strain exhibit complex nonlinear dynamic behavior. Ultrasonic cavitation damage was tested and evaluated on human umbilical vein endothelial cells. RESULTS: The results indicated that the cellular network damage was positively correlated with force amplitude and pulse frequency and was negatively correlated with driving frequency. The time lag and the internal force of cellular junctions have an important influence on the resistance to damage of the cellular network due to external forces. The damage experiment based on ultrasonic cavitation confirmed the effectiveness of the proposedmodel. CONCLUSIONS: The model provided a platform for understanding the damage mechanism of endothelial tissues and ultimately improving options for their prevention and treatment.
摘要：
The problem of designing explicit bent and plateaued functions has been researched for several decades. However, finding new bent functions outside the well-known completed Maiorana-McFarland class $\mathcal {M}^{\#}$ is still a challenge. Plateaued functions have been characterized in many different ways, but there is no general and rigorous mathematical method to generate them directly, except for the ones in the spirit of the well-known Maiorana-McFarland constructions or those obtained through adaptations of the secondary constructions of bent functions. Jeong and Lee recently made significant advances regarding algorithms for constructing balanced plateaued functions with maximal algebraic degrees in [IEEE Trans. Inf. Theory, 70(2), 1408-1421, 2024]. Due to the gap between our significant interest in the notion of plateaued functions and the knowledge we have on it, our motivation is to bring further results on the constructions of plateaued functions that allow us to understand their structure better. This article creates a framework of new generic constructions of bent and plateaued functions by studying Boolean functions of the form $h(x)=f(x)+F(f_{1}(x),\ldots, f_{r}(x))$ , where $f_{i}(x)=f(x)+f(x+\mu _{i})$ for each $1\leq i\leq r$ . We firstly prove that h and f have the same extended Walsh-Hadamard spectrum if $D_{\mu _{i}}D_{\mu _{j}}f=0$ for any $1\leq i\lt j\leq r$ . This result extends a previous construction of bent functions to any Boolean functions. The strength of such a result is that it allows us to obtain several plateaued functions of high algebraic degrees from known ones with low algebraic degrees, which was a significant and challenging problem raised in the literature. Such a result is a real challenge and breaks a deadlock since no mathematical method allows the general constructions of plateaued functions. We next give an extended affine equivalent form of the function h, which provides us with another compelling perspective to design new bent functions (including those which are outside $\mathcal {M}^{\#}$ from certain known ones inside $\mathcal {M}^{\#}$ ) and plateaued functions. Finally, we present four generic constructions of bent functions outside $\mathcal {M}^{\#}$ from generalized Maiorana-McFarland functions.
摘要：
Let p be an odd prime and n a positive integer. This paper focuses on the investigation of permutation quadrinomials with generalized Niho exponents over finite fields of odd characteristic. Inspired by the works in [10] , we study two classes of permutation quadrinomials over F p n and a class of permutation quadrinomials over F 5 n . Finally, we verify that permutation quadrinomials presented in this paper are multiplicative inequivalent to known ones.
Let p be an odd prime and n a positive integer. This paper focuses on the investigation of permutation quadrinomials with generalized Niho exponents over finite fields of odd characteristic. Inspired by the works in [10] , we study two classes of permutation quadrinomials over F p n and a class of permutation quadrinomials over F 5 n . Finally, we verify that permutation quadrinomials presented in this paper are multiplicative inequivalent to known ones.
作者机构：
[Xiao, Qizhen; Liu, Hongliang; Xu, Qiming] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Song, Yingming] CNNC, Nucl Ind Coll, Beijing 102618, Peoples R China.
通讯机构：
[Song, YM ] C;CNNC, Nucl Ind Coll, Beijing 102618, Peoples R China.
关键词：
Adaptive finite-time state observer;Preassigned-time stable controller;Control rod drive mechanism faults;Sensor noises;Small modular reactor
摘要：
Load Following (L-F) control of Nuclear Power Plant (NPP) under actuator faults and measurement noises remains challenging both in theory and in practice. To solve this challenge, a globally preassigned-time stable fault-tolerant control strategy of rapid L-F for a Pressurized Water Reactor based Small Modular Reactors (PWR-SMR) under control rod drive mechanism (CRDM) faults and sensor noises is first proposed. From a practical standpoint, considering some states of PWR-SMR cannot be measured directly and the sensor noises in practice, a finite-time tracking differentiator and a nonlinear adaptive practical finite-time state observer are tactfully constructed, which can guarantee that the observation error system converges to a small residual set within a finite-time. Under the framework of Filippov solution, the differential inclusion technique is used to tackle the power error system which may be discontinuous. In addition, to compensate the adverse effects of the CRDM faults, a radial basis function neural network (RBFNN) is employed with a preassigned-time convergent updated law. Then two preassigned-time stable controllers are proposed to guarantee that the prescribed performance of L-F for PWR-SMR can be realized within a preassigned-time. At last, simulation studies, involving performances of L-F, tracking differentiator, finite-time observer and uncertainty of parameters, demonstrate the effectiveness and feasibility of the theoretical results.
Load Following (L-F) control of Nuclear Power Plant (NPP) under actuator faults and measurement noises remains challenging both in theory and in practice. To solve this challenge, a globally preassigned-time stable fault-tolerant control strategy of rapid L-F for a Pressurized Water Reactor based Small Modular Reactors (PWR-SMR) under control rod drive mechanism (CRDM) faults and sensor noises is first proposed. From a practical standpoint, considering some states of PWR-SMR cannot be measured directly and the sensor noises in practice, a finite-time tracking differentiator and a nonlinear adaptive practical finite-time state observer are tactfully constructed, which can guarantee that the observation error system converges to a small residual set within a finite-time. Under the framework of Filippov solution, the differential inclusion technique is used to tackle the power error system which may be discontinuous. In addition, to compensate the adverse effects of the CRDM faults, a radial basis function neural network (RBFNN) is employed with a preassigned-time convergent updated law. Then two preassigned-time stable controllers are proposed to guarantee that the prescribed performance of L-F for PWR-SMR can be realized within a preassigned-time. At last, simulation studies, involving performances of L-F, tracking differentiator, finite-time observer and uncertainty of parameters, demonstrate the effectiveness and feasibility of the theoretical results.
