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In-flight Energy Calibration of the GECAM Gamma-ray Detectors

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Research in Astronomy and Astrophysics 2024年第10期24卷 48-57页

作者： Rui Qiao Dong-Ya Guo Wen-Xi Peng Yan-Qiu Zhang Shuo Xiao Shao-Lin Xiong Chao Zheng Chao-Yang Li Jia-Cong Liu Wang-Chen Xue Jian-Jian He Zheng-Hua An Da-Li Zhang Xin-Qiao Li Li-Ming Song Shi-Jie Zheng Ke Gong Ya-Qing Liu Xin-Ying Song Xiao-Yun Zhao Xiang-Yang Wen Yan-Bing Xu Xiang Ma Xiao-Bo Li Ping Wang Yue Huang Ce Cai Qi-Bin Yi Yi Zhao Chen-Wei Wang Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China university of Chinese Academy of sciences Beijing 100049China China West normal university Nanchong 637002China Xiangtan university Xiangtan 411105China beijing normal university Beijing 100875China

The Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)mission is designed to monitor the Gamma-Ray Bursts(GRBs)associated with gravitational waves and other high-energy transient *** mission consists of two microsatellites which are planned to operate at the opposite sides of the *** GECAM satellite could detect and localize GRBs in about 8 keV-5 MeV with its 25 Gamma-Ray Detectors(GRDs).In this work,we report the in-flight energy calibration of GRDs using the characteristic gamma-ray lines in the background spectra,and show their performance evolution during the commissioning ***,a preliminary cross-calibration of energy response with Fermi GBM data is also presented,validating the energy response of GRDs.

关键词： (stars:)gamma-ray burst:general instrumentation:detectors methods:data analysis

Deep-learning architecture for PM_(2.5) concentration prediction: A review

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Environmental Science and Ecotechnology 2024年第5期21卷 17-33页

作者： Shiyun Zhou Wei Wang Long Zhu Qi Qiao Yulin Kang Institute of Environmental Information Chinese Research Academy of Environmental SciencesBeijing 100012China school of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China College of Water sciences Beijing Normal UniversityBeijing 100875China

Accurately predicting the concentration of fine particulate matter(PM_(2.5))is crucial for evaluating air pollution levels and public *** advancements have seen a significant rise in using deep learning(DL)models for forecasting PM_(2.5) ***,there is a lack of unified and standardized frameworks for assessing the performance of DL-based PM_(2.5) prediction *** we extensively reviewed those DL-based hybrid models for forecasting PM_(2.5) levels according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)*** examined the similarities and differences among various DL models in predicting PM_(2.5) by comparing their complexity and *** categorized PM_(2.5) DL methodologies into seven types based on performance and application conditions,including four types of DL-based models and three types of hybrid learning *** research indicates that established deep learning architectures are commonly used and respected for their ***,many of these models often fall short in terms of innovation and ***,models hybrid with traditional approaches,like deterministic and statistical models,exhibit high interpretability but compromise on accuracy and ***,hybrid DL models,representing the pinnacle of innovation among the studied models,encounter issues with *** introduce a novel three-dimensional evaluation framework,i.e.,Dataset-MethodExperiment Standard(DMES)to unify and standardize the evaluation for PM_(2.5) predictions using DL *** review provides a framework for future evaluations of DL-based models,which could inspire researchers to standardize DL model usage in PM_(2.5) prediction and improve the quality of related studies.

关键词： PM_(2.5)concentration prediction Deep-learning based model Bibliometrics analysis Evaluation framework

THE NYSTROM METHOD FOR ELASTIC WAVE SCATTERINGBY UNBOUNDED ROUGH SURFACES

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Journal of Computational Mathematics 2024年第5期42卷 1407-1426页

作者： Jianliang Li Xiaoli Liu Bo Zhang Haiwen Zhang Key Laboratory of Computing and Stochastic Mathematics School of Mathematics and StatisticsHunan Normal UniversityChangsha 410081China school of mathematical sciences Beihang UniversityBeijing 100191China LSEC and Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China school of mathematical sciences University of Chinese Academy of SciencesBeijing 100049China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

We consider a numerical algorithm for the two-dimensional time-harmonic elastic wave scattering by unbounded rough surfaces with Dirichlet boundary condition.A Nystr¨om method is proposed for the scattering problem based on the integral equation *** of the Nystr¨om method is established with convergence rate depending on the smoothness of the rough *** doing so,a crucial role is played by analyzing the singularities of the kernels of the relevant boundary integral *** experiments are presented to demonstrate the effectiveness of the *** subject classification:35P25,45P05.

关键词： Elastic wave scattering Unbounded rough surface Nystrom method

Supermassive black holes triggered by QCD axion bubbles

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Communications in Theoretical Physics 2024年第5期76卷 134-139页

作者： Hai-Jun Li Ying-Quan Peng Wei Chao Yu-Feng Zhou Key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Center for Advanced Quantum Studies Department of PhysicsBeijing Normal UniversityBeijing 100875China school of Physical sciences University of Chinese Academy of SciencesBeijing 100049China school of Fundamental Physics and mathematical sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China International Centre for Theoretical Physics Asia-Pacific Beijing/HangzhouChina

Supermassive black holes(SMBHs)are ubiquitous in the center of galaxies,although the origin of their massive seeds is still *** this paper,we investigate the formation of SMBHs from the quantum chromodynamics(QCD)axion *** this case,primordial black holes(PBHs)are considered as the seeds of SMBHs,which are generated from the QCD axion bubbles due to an explicit Peccei–Quinn(PQ)symmetry breaking after *** QCD axion bubbles are formed when the QCD axion starts to oscillate during the QCD phase *** consider a general case in which the axion bubbles are formed with the bubble effective angle θ_(eff)∈(0,π],leading to the minimum PBH mass∼■(10^(4)−10^(7))M⊙for the axion decay constant f_(a)∼■(10^(16))*** PBHs at this mass region may account for the seeds of SMBHs.

关键词： supermassive black holes primordial black holes quantum chromodynamics axion

The symmetric space,strong isotropy irreducibility and equigeodesic properties

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Science China Mathematics 2024年第1期67卷 129-148页

作者： Ming Xu Ju Tan school of mathematical sciences Capital Normal UniversityBeijing 100048China school of Microelectronics and Data Science Anhui University of TechnologyMa'anshan 243032China

A smooth curve on a homogeneous manifold G/H is called a Riemannian equigeodesic if it is a homogeneous geodesic for any G-invariant Riemannian *** homogeneous manifold G/H is called Riemannian equigeodesic,if for any x∈G/H and any nonzero y∈Tx(G/H),there exists a Riemannian equigeodesic c(t) with c(0)=x and ■(0)=*** two notions can be naturally transferred to the Finsler setting,which provides the definitions for Finsler equigeodesics and Finsler equigeodesic *** prove two classification theorems for Riemannian equigeodesic spaces and Finsler equigeodesic spaces,***,a homogeneous manifold G/H with a connected simply connected quasi compact G and a connected H is Riemannian equigeodesic if and only if it can be decomposed as a product of Euclidean factors and compact strongly isotropy irreducible ***,a homogeneous manifold G/H with a compact semisimple G is Finsler equigeodesic if and only if it can be locally decomposed as a product,in which each factor is Spin(7)/G2,G2/SU (3) or a symmetric space of compact *** results imply that the symmetric space and the strongly isotropy irreducible space of compact type can be interpreted by equigeodesic *** an application,we classify the homogeneous manifold G/H with a compact semisimple G such that all the G-invariant Finsler metrics on G/H are *** suggests a new project in homogeneous Finsler geometry,i.e.,to systematically study the homogeneous manifold G/H on which all the G-invariant Finsler metrics satisfy a certain geometric property.

关键词： equigeodesic equigeodesic space flag manifold orbit type stratification symmetric space strongly isotropy irreducible space

A Hierarchical Method for Locating the Interferometric Fringes of Celestial Sources in the Visibility Data

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Research in Astronomy and Astrophysics 2024年第3期24卷 110-128页

作者： Rong Ma Ruiqing Yan Hanshuai Cui Xiaochun Cheng Jixia Li Fengquan Wu Zongyao Yin Hao Wang Wenyi Zeng Xianchuan Yu school of Artificial Intelligence Beijing Normal UniversityBeijing 100875China Department of Computer Science Swansea UniversitySwanseaSA18ENUK National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China

In source detection in the Tianlai project,locating the interferometric fringe in visibility data accurately will influence downstream tasks drastically,such as physical parameter estimation and weak source *** that traditional locating methods are time-consuming and supervised methods require a great quantity of expensive labeled data,in this paper,we first investigate characteristics of interferometric fringes in the simulation and real scenario separately,and integrate an almost parameter-free unsupervised clustering method and seeding filling or eraser algorithm to propose a hierarchical plug and play method to improve location ***,we apply our method to locate single and multiple sources’interferometric fringes in simulation ***,we apply our method to real data taken from the Tianlai radio telescope ***,we compare with unsupervised methods that are state of the *** results show that our method has robustness in different scenarios and can improve location measurement accuracy effectively.

关键词： methods data analysis-techniques image processing-techniques interferometric

On Minor Left Prime Factorization Problem for Multivariate Polynomial Matrices

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Journal of Systems Science & Complexity 2024年第3期37卷 1295-1307页

作者： LU Dong WANG Dingkang XIAO Fanghui school of Mathematics Southwest Jiaotong UniversityChengdu 610031China KLMM Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China school of mathematical sciences University of Chinese Academy of SciencesBeijing 100049China MOE-LCSM School of Mathematics and StatisticsHunan Normal UniversityChangsha 410081China

A new necessary and sufficient condition for the existence of minor left prime factorizations of multivariate polynomial matrices without full row rank is *** key idea is to establish a relationship between a matrix and any of its full row rank *** on the new result,the authors propose an algorithm for factorizing matrices and have implemented it on the computer algebra system *** examples are given to illustrate the effectiveness of the algorithm,and experimental data shows that the algorithm is efficient.

关键词： Free modules Grobner bases minor left prime(MLP) multivariate polynomial matrices polynomial matrix factorizations

The Non-inclusion Diagnosability of Hypercubes Under the PMC Model

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Journal of the Operations Research Society of China 2024年第2期12卷 478-484页

作者： Mei-Jie Ma Min Xu Tong-Tong Ding Xiang-Jun Li Qiang Zhu school of Mathematics and Statistics Qilu University of Technology(Shandong Academy of Sciences)Jinan 250353ShandongChina school of mathematical sciences Beijing Normal UniversityLaboratory of Mathematics and Complex SystemsMinistry of EducationBeijing 100875China school of Information and Mathematics Yangtze UniversityJingzhou 434023HubeiChina school of Mathematics and Statistics XiDian UniversityXi'an 710071ShaanXiChina

Diagnosability of a multiprocessor system is an important measure of the reliability of interconnection ***-level diagnosis is a primary strategy to identify the faulty processors in a multiprocessor *** on a sound assumption proposed by Zhu et ***,we proposed a new diagnosability named non-inclusion diagnosability and showed that the non-inclusion diagnosability t_(N)(Q_(n))of the hypercube under the PMC model is *** is,assume that if two vertex sets F_(1) and F_(2) are both consistent with a syndrome and F_(1)C F_(2),then F_(2) is not the faulty set which we are looking for;the faulty set F is 1-step diagnosable if|F|≤2n-2 in Q_(n) under the PMC model.

关键词： Interconnection network Diagnosability Hypercube PMC model

New black-to-white hole solutions with improved geometry and energy conditions

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 30-43页

作者： Zhongwen Feng Yi Ling Xiaoning Wu Qingquan Jiang school of Physics and Astronomy China West Normal UniversityNanchong 637009China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China school of Physics University of Chinese Academy of SciencesBeijing 100049China Institute of Mathematics Academy of Mathematics and System Science and Hua Loo-Keng Key Laboratory of MathematicsChinese Academy of SciencesBeijing 100190China school of mathematical sciences University of Chinese Academy of SciencesBeijing 100190China

We construct new black-to-white hole solutions which connect the geometry of spacetime at some gluing surface inside the *** continuity of the metric can be guaranteed up to the arbitrary order which is controlled by the power factor *** sort of black-to-white holes is characterized by the sub-Planckian scalar curvature,independent of the mass of black-to-white *** importantly,we show that the energy condition is only violated within a small region near the gluing *** geodesics of particles within the region from black hole to white hole is also *** turns out that the matter falling into the black hole may pass through the center without singularity and come out from the white *** scenario provides novel ideas for understanding the information loss paradox in traditional black hole physics.

关键词： regular black hole energy condition singularity quantum gravity