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.
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：
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 10 12 to 10 16 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 .
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.
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.
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.
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：
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 10 6 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：
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 .
期刊：
Journal of Biomedical Physics and Engineering,2025年15(1):15-26 ISSN：2251-7200
作者机构：
[Dong, Hu] School of Information Science and Engineering, Changsha Normal University, Changsha 410100, China;[Hu, Jiwen] School of Mathematics and Science, Nanhua University, Hengyang, 421001, China;[Zou, Xiao] School of Physics and Electronics, Hunan Normal University, Changsha 410081, China;[Chen, Wei] School of Electronic Information and Electrical Engineering, Changsha University, Changsha, 410022, China
摘要：
BACKGROUND: High-intensity Focused Ultrasound (HIFU) is a rapidly developing non-invasive treatment method for tumors in recent years. OBJECTIVE: The present study aimed to investigate the lesion and temperature effects of HIFU combined with different concentrations and volumes of ethanol on porcine liver. MATERIAL AND METHODS: In this experimental study, different concentrations and volumes of ethanol were injected into the focal area of porcine liver using B-mode ultrasound, and the focal temperature was monitored using a k-type needle thermocouple. The peak negative pressure and sound intensity at the focal point of porcine liver were calculated by Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation. Further, the presence of cavitation effects within porcine liver was further determined by ultrasound hyperechoic. The differences in lesion volume and temperature, caused by different concentrations and volumes of ethanol on porcine liver, were measured. RESULTS: HIFU irradiation combined with ethanol injection caused greater lesion volume and higher focal temperature in porcine liver. At the same HIFU irradiation power, an increase in the volume of ethanol resulted in an increase in lesion volume and focal temperature. At a fixed volume of ethanol injected and HIFU irradiation power, higher ethanol concentrations resulted in higher lesion volumes and focal temperature. CONCLUSION: The combination of HIFU and ethanol synergistically affects the lesion of porcine liver, manifested as the larger the ethanol concentration and volume, the larger the lesion volume and the higher the focal temperature.
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：
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：
FORTSCHRITTE DER PHYSIK-PROGRESS OF PHYSICS,2025年:2400236 ISSN：0015-8208
通讯作者：
Xiaoyan Zhu<&wdkj&>Wenbin Lin<&wdkj&>Siming Liu
作者机构：
[Xiaoyan Zhu] School of Mathematics and Physics, University of South China, Hengyang, China;[Wei Gao; Siming Liu] School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, China;[Wenbin Lin] School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, China<&wdkj&>School of Mathematics and Physics, University of South China, Hengyang, China
通讯机构：
[Xiaoyan Zhu; Wenbin Lin; Siming Liu] S;School of Mathematics and Physics, University of South China, Hengyang, China<&wdkj&>School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, China<&wdkj&>School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, China<&wdkj&>School of Mathematics and Physics, University of South China, Hengyang, China
关键词：
perihelion precession;post-newtonian approximations;quasi-keplerian motion;Sen black hole
摘要：
Based on the Sen spacetime, the orbital energy and angular momentum are calculated, and the solution for the motion of a test particle derived to the second post-Newtonian order. The effect of the Sen black hole's charge q m $q_{m}$ on the periastron advance and orbital period is obtained. In particular, it is found that q m $q_{m}$ has an influence on perihelion precession at both the first and second post-Newtonian orders, whereas its effect on the orbital period is confined solely to the second post-Newtonian order. Finally, the precession of the star S2 is used to constrain our model and the value of q m / M $q_m/M$ is 0.51.
作者机构：
[Ou, Qi; Ma, Wankun; Wang, Shuangshuang; Gong, Xueyu] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Yin, Lan; Chen, You; Yin, L] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Peng, Yaoyi] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.;[Zheng, Pingwei] Univ South China, Sch Resources Environm & Safety Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Yin, L ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
关键词：
minority ion heating;stellarator;ICRF
摘要：
A preliminary simulation of ion cyclotron resonance heating (ICRH) in the poloidal cross-section at the antenna location of the CN-H1 (Chinese Heliac 1) stellarator has been conducted for the first time using the full-wave solver TORIC. The heating scheme employed focuses on minority ion heating of He 4 (H), with an independent investigation into the effects of wave frequency, toroidal mode number, and minority ion concentration on ICRH. Preliminary simulation results indicate that, under the conditions of wave frequency f = 4.7MHz, central magnetic field B 0 = 0.32T and low-temperature, low-density plasma (with density on the order of 10 18 m −3 and temperature in the range of tens of eV), more efficient minority-ion heating can be achieved when the toroidal mode number is in the range of 10–20 and the minority ion concentration is between 15% and 30%. This simulation provides theoretical insights and delineates the parameter space for prospective ICRH experiments in CN-H1.
摘要：
Let q = 2 m . In this paper, we propose several classes of permutation pentanomials of the form ϵ 0 x d 0 + L ( ϵ 1 x d 1 + ϵ 2 x d 2 ) over F q n ( 2 ≤ n ≤ 4 ) from some certain linearized polynomial L ( x ) by using multivariate method and some techniques to determine the solutions of some equations. Furthermore, two classes of permutation pentanomials over F q n for n satisfying 3 | q n − 1 are also constructed based on some bijections over the unit circle U τ of F q n with order τ = q n − 1 + q n − 2 + ⋯ + q 2 + q + 1 .
Let q = 2 m . In this paper, we propose several classes of permutation pentanomials of the form ϵ 0 x d 0 + L ( ϵ 1 x d 1 + ϵ 2 x d 2 ) over F q n ( 2 ≤ n ≤ 4 ) from some certain linearized polynomial L ( x ) by using multivariate method and some techniques to determine the solutions of some equations. Furthermore, two classes of permutation pentanomials over F q n for n satisfying 3 | q n − 1 are also constructed based on some bijections over the unit circle U τ of F q n with order τ = q n − 1 + q n − 2 + ⋯ + q 2 + q + 1 .
通讯机构：
[Long, F ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
摘要：
Recently, magnetic reconnection has attracted considerable attention as a novel energy extraction mechanism, relying on the rapid reconnection of magnetic field lines within the ergosphere. We have investigated the properties of the energy extraction via magnetic reconnection in a Konoplya-Zhidenko rotating non-Kerr black hole spacetime with an extra deformation parameter. Our results show that the positive deformation parameter expands the possible region of energy extraction and improves the maximum power, maximum efficiency, and the maximum ratio of energy extraction between magnetic reconnection and the Blandford-Znajek process. This means that in the Konoplya-Zhidenko rotating non-Kerr black hole spacetime one can extract more energy via magnetic reconnection than in the Kerr black hole case. These effects of the deformation parameter may provide valuable clues for future astronomical observations of black holes and verification of gravity theories.
摘要：
The ASE (Amplified Spontaneous Emission) light source, based on erbium-doped fiber (EDF), is a broadband light source with advantages such as high power, excellent temperature stability, and low coherent light generation. It is widely used in the field of fiber optic sensing. However, traditional ASE sources suffer from temperature sensitivity and low efficiency, which can compromise the accuracy and stability of the output light's average wavelength. This study focuses on optimizing the erbium-doped fiber (EDF) to improve the temperature stability and efficiency of the ASE light source. Through simulations, we found that the appropriate doping concentration and length of the EDF are key factors in enhancing the stability and efficiency of the ASE source. Inorganic metal chloride vapor-phase doping combined with an improved chemical vapor deposition process was used to fabricate the erbium-doped fiber, ensuring low background loss, minimal OH- absorption, and uniform distribution of the erbium ions in the core of the fiber. The optimized EDFs were integrated into the ASE source, achieving a power conversion efficiency of 53.6% and a temperature stability of 0.118 ppm/degrees C within the temperature range of -50 degrees C to 70 degrees C. This study offers a practical approach for improving the performance of ASE light sources and advancing the development of high-precision fiber optic sensing technologies.
作者机构：
[Zhou, Menghu; Shi, Yunqing; Gu, Yadong; Liu, Qingsong; Yang, Qingsong; Ren, Zhi-An; Yi, Junkun; Ruan, Binbin; Chen, Lewei] Chinese Acad Sci, Beijing Natl Lab Condensed Matter Phys, Inst Phys, Beijing 100190, Peoples R China.;[Zhou, Menghu] Hunan Inst Technol, Sch Sci, Hengyang 421002, Peoples R China.;[Ni, Shunli; Ni, SL] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Shi, Yunqing; Liu, Qingsong; Yang, Qingsong; Ren, Zhi-An; Yi, Junkun; Chen, Lewei] Univ Chinese Acad Sci, Sch Phys Sci, Beijing 100049, Peoples R China.;[Yu, Jia] Quantum Sci Ctr, Guangdong Hong Kong Macao Greater Bay Area, Hong Kong 518045, Peoples R China.
通讯机构：
[Zhou, MH ] C;[Ni, SL ] U;Chinese Acad Sci, Beijing Natl Lab Condensed Matter Phys, Inst Phys, Beijing 100190, Peoples R China.;Hunan Inst Technol, Sch Sci, Hengyang 421002, Peoples R China.;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
摘要：
4Ha-NbSe2 single crystals were grown by the chemical vapor transport method followed by a quench to room temperature. The temperature-dependent magnetization and in-plane resistance reveal that the sample exhibits both charge-density-wave and superconducting orders, condensing at TCDW 43 K and Tc 6.5 K, respectively. The superconductivity was studied by specific heat and lower critical field (Hc1) down to 0.5 and 0.4 K, respectively. The electronic specific heat at superconducting state could be well described by an isotropic two-gap BCS model. The superconducting gaps were obtained to be of AL = 1.1 meV and AS = 0.3 meV with the weighting factors as 0.938 and 0.062, respectively. The in-plane Hc1//ab(T) and out-of-plane H//c c1 (T ) also support the two-gap s + s-wave scenario, which derives Hc1'/ab(0) and H//c c1 (0) as 78.3 and 149.8 Oe, respectively. The anisotropic parameter at 0 K based on Hc1 [PHc1 (0)] was deduced to be 1.9. Our results reveal nodeless two-gap pairing symmetry in 4Ha-NbSe2, which would gain more insight into the superconductivity of TMDs.
摘要：
Uranium is a rare and important energy mineral. In order to study the distribution characteristics of uranium deposits, we establish a data restoration algorithm with fractal features and sparse known point data. The algorithm ensures the accuracy of the restoration and the retention of fractal features through the steps of determining the basis function, preserving the dimension invariant restoration, and dimension greedy optimization. By comparing the numerical test with the Kriging interpolation method, it is proved that the algorithm is better in accuracy error and dimension error when restoring the fractal feature data.
期刊：
EUROPEAN PHYSICAL JOURNAL C,2025年85(1):1-9 ISSN：1434-6044
通讯作者：
Lin, WB
作者机构：
[Zhang, Feng-Yi] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Lin, Wenbin; Lin, WB; Zhang, Feng-Yi] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;[Lin, Wenbin; Lin, WB; Zhang, Feng-Yi] Univ South China, Hunan Key Lab Math Modeling & Sci Comp, Hengyang 421001, Peoples R China.
通讯机构：
[Lin, WB ] U;Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.;Univ South China, Hunan Key Lab Math Modeling & Sci Comp, Hengyang 421001, Peoples R China.
摘要：
The Hamilton–Jacobi approach offers a natural framework for analyzing inflationary dynamics, relying on the specified Hubble parameter rather than the potential, particularly in extended gravity theories. In this study, we apply this method to investigate inflation with non-minimal coupling, comparing the metric and Palatini formulations. Using a power-law Hubble parameter in the Jordan frame, we find that both formalisms satisfy the attractor condition, with a slight suppression in the Palatini case. Our results align closely with the latest observational data, demonstrating the Palatini formalism’s heightened sensitivity to coupling constants and model parameters. Furthermore, we show that within the model’s viable parameter space, the reheating process can achieve sufficiently high temperatures to support successful leptogenesis.
作者：
Xu, Qiming;Liu, Hongliang;Xiao, Qizhen;Zeng, Wenjie;Luo, Run
期刊：
Annals of Nuclear Energy,2025年216:111259 ISSN：0306-4549
通讯作者：
Liu, HL
作者机构：
[Xiao, Qizhen; Liu, Hongliang; Xu, Qiming; Liu, HL] 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.;[Luo, Run] Univ South China, Sch Resources Environm & Safety 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：
Fixed-time stability;Adaptive learning observer;Load following;Pressurized water reactor;Compound disturbances
摘要：
Enhancing the load following capacity of Nuclear Power Plants (NPPs) remains a challenge. This paper focuses on designing a fixed-time stable controller for load following operation of a Pressurized Water Reactor (PWR) with compound disturbances. To compensate the limitation of current measuring techniques, an adaptive learning observer is firstly proposed to estimate the hard-to-measure states like Xenon concentration, Iodine concentration, average reactor fuel temperature and the compound disturbances of the PWR system. Based on these important information, in order to ensure that the output power of PWR can rapidly and accurately follow the prescribed idea power, a fixed-time stable controller is presented. Sequentially, Lyapunov method is employed to verify that the control system can be stable within a fixed-time, which upper bound can be accurately calculated by some parameters. Finally, simulation results are provided to illustrate the effectiveness of the designed controller in the load following operation and the performance of the adaptive learning observer.
Enhancing the load following capacity of Nuclear Power Plants (NPPs) remains a challenge. This paper focuses on designing a fixed-time stable controller for load following operation of a Pressurized Water Reactor (PWR) with compound disturbances. To compensate the limitation of current measuring techniques, an adaptive learning observer is firstly proposed to estimate the hard-to-measure states like Xenon concentration, Iodine concentration, average reactor fuel temperature and the compound disturbances of the PWR system. Based on these important information, in order to ensure that the output power of PWR can rapidly and accurately follow the prescribed idea power, a fixed-time stable controller is presented. Sequentially, Lyapunov method is employed to verify that the control system can be stable within a fixed-time, which upper bound can be accurately calculated by some parameters. Finally, simulation results are provided to illustrate the effectiveness of the designed controller in the load following operation and the performance of the adaptive learning observer.
期刊：
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing,2025年18:4174-4187 ISSN：1939-1404
通讯作者：
Feng, GC
作者机构：
[Xiong, Zhiqiang; Li, Ning; Feng, Guangcai; Chen, Hesheng; Jiang, Hongbo] Cent South Univ, Sch Geosci & Info Phys, Changsha 410083, Peoples R China.;[Wang, Yuexin] Wuhan Geomat Inst, Wuhan 430022, Peoples R China.;[Lin, Zeng] Univ South China, Sch Math & Phys, Hengyang 421001, Peoples R China.
通讯机构：
[Feng, GC ] C;Cent South Univ, Sch Geosci & Info Phys, Changsha 410083, Peoples R China.
关键词：
Interferometry;Synthetic aperture radar;Climate change;Rivers;Global warming;Land use planning;Interferometric synthetic aperture radar (InSAR);land subsidence (LS);Yangtze river delta (YRD)
摘要：
The combined effects of global warming and human activities have intensified land subsidence (LS), limiting the sustainable development of economy in delta regions. Despite the potential of interferometric synthetic aperture radar (InSAR) for monitoring LS, its application across vast delta regions may be hindered by complex data processing, high computational demands, and the need for standardized results. To overcome these challenges, we adopted the multitemporal InSAR technique, integrating a frame data parallel processing strategy and an overall adjustment correction method, to obtain the temporal deformation sequences of the entire Yangtze River Delta (YRD) region in China from January 2019 to December 2021. We calculated the annual average deformation rate and identified deformation areas, with 73.5% concentrated along the Yangtze River, along the coastline, and within the northern Anhui mining area. A significant correlation was observed between LS and anthropogenic activities, such as economic development and land reclamation activities. Further analysis reveals that the increase in GDP growth rate may contribute to LS. Approximately, 38% of the reclaimed area in the YRD is at risk of LS. Land reclamation activities present a dichotomy, with Hangzhou Bay as the dividing line. This study provides a new perspective and scientific basis for understanding and analyzing LS in deltaic environments, contributing to sustainable development and advancing wide-area InSAR deformation monitoring.
