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A generalization of b.nach's lemma and its applications to perturb.tions of b.unded linear operators

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Applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 363-369页

作者： WANG zi DING Jiu WANG Yu-wen School of Mathematics Sciences Harbin Normal UniversityHarbin 150025China School of Mathematics and Natural Sciences The University of Southern MississippiHattiesburg MS 39406-5043USA Academic Committee Harbin Institute of PetroleumHarbin 150027China

Let X b. a b.nach space and let P:X→X b. a b.unded linear *** an algeb.aic inequality on the spectrum of P,we give a new sufficient condition that guarantees the existence of(I-P)^(-1) as a b.unded linear operator on X,and a b.und on its spectral radius is also *** generalizes the classic b.nach *** apply the result to the perturb.tion analysis of general b.unded linear operators on X with commutative perturb.tions.

关键词： b.nach lemma spectral radius generalized inverse perturb.tion analysis

Weyl Type Theorem for b.unded Linear Operator and Its Functional Calculus

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Acta Mathematica Sinica,English Series 2024年第2期40卷 528-536页

作者： Gao Hui zi FENG Peng Tong LI School of Mathematics Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China

Let H b. a complex infinite dimensional Hilb.rt space and b.H)b. the algeb.a of all b.unded linear operators on *** this paper,we mainly study the operators that satisfy b.th a-Weyl's theorem and property(R).Also,the operators whose functional calculus satisfies the two properties are also *** give the features for the operator or its functional calculus for which b.th a-Weyl's theorem and property(R)hold.

关键词： a-Weyl's theorem property(R) functional calculus

Rapid prediction of damaged ship roll motion responses in b.am waves b.sed on stacking algorithm

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Journal of Hydrodynamics 2024年第2期36卷 394-405页

作者： Xin-ran Liu Ting-qiu Li zi-ping Wang School of Naval Architecture Ocean and Energy Power EngineeringWuhan University of TechnologyWuhan430063China

Accurate modeling for highly non-linear coupling of a damaged ship with liquid sloshing in waves is still of considerab.e interest within the computational fluid dynamics(CFD)and AI *** paper describ.s a data-driven Stacking algorithm for fast prediction of roll motion response amplitudes in b.am waves b. constructing a hydrodynamics model of a damaged ship b.sed on the dynamic overlapping grid CFD *** general idea is to optimize various parameters varying with four types of classical b.se models like multi-layer perception,support vector regression,random forest,and hist gradient b.osting *** offers several attractive properties in terms of accuracy and efficiency b. choosing the standard DTMb.5415 model with doub.e damaged compartments for *** is clearly demonstrated that the predicted response amplitude operator(RAO)in the regular b.am waves agrees well with the experimental data availab.e,which verifies the accuracy of the estab.ished damaged ship hydrodynamics *** high-quality CFD samples,therefore,implementation of the designed Stacking algorithm with its optimal comb.nation can predict the damaged ship roll motion amplitudes effectively and accurately(e.g.,the coefficient of determination 0.9926,the average ab.olute error 0.0955 and CPU 3s),b. comparison of four types of typical b.se models and their various ***,the estab.ished Stacking algorithm provides one potential that can b.eak through prob.ems involving the time-consuming and low efficiency for large-scale lengthy CFD simulations.

关键词： Ship motion damaged ship computational fluid dynamics(CFD) machine learning stacking algorithm

An Interpolation Method for Karhunen-Loève Expansion of Random Field Discretization

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工程与科学中的计算机建模(英文) 2024年第1期138卷 245-272页

作者： zi Han Zhentian Huang Department of Engineering Mechanics Hohai UniversityNanjing211100China College of Civil and Transportation Engineering Shenzhen UniversityGuangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and UtilizationInstitute of Deep Earth Sciences and Green EnergyShenzhenChina

In the context of glob.l mean square error concerning the numb.r of random variab.es in the representation,the Karhunen–Loève(KL)expansion is the optimal series expansion method for random field *** computational efficiency and accuracy of the KL expansion are contingent upon the accurate resolution of the Fredholm integral eigenvalue prob.em(IEVP).The paper proposes an interpolation method b.sed on different interpolation b.sis functions such as moving least squares(MLS),least squares(LS),and finite element method(FEM)to solve the *** with the Galerkin method b.sed on finite element or Legendre polynomials,the main advantage of the interpolation method is that,in the calculation of eigenvalues and eigenfunctions in one-dimensional random fields,the integral matrix containing covariance function only requires a single integral,which is less than a two-folded integral b. the Galerkin *** effectiveness and computational efficiency of the proposed interpolation method are verified through various one-dimensional ***,b.sed on theKL expansion and polynomial chaos expansion,the stochastic analysis of two-dimensional regular and irregular domains is conducted,and the b.sis function of the extended finite element method(XFEM)is introduced as the interpolation b.sis function in two-dimensional irregular domains to solve the IEVP.

关键词： Random field discretization KL expansion IEVP MLS FEM stochastic analysis

Reliab.e calculations of nuclear b.nding energies b. the Gaussian process of machine learning

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Nuclear Science and Techniques 2024年第6期35卷 130-144页

作者： zi-Yi Yuan Dong b.i Zhen Wang Zhong-Zhou Ren School of Physics Science and Engineering Tongji UniversityShanghai 200092China College of Science Hohai UniversityNanjing 211100China Key Lab.ratory of Advanced Micro-Structure Materials Ministry of EducationShanghai 200092China

Reliab.e calculations of nuclear b.nding energies are crucial for advancing the research of nuclear physics. Machine learning provides an innovative approach to exploring complex physical prob.ems. In this study, the nuclear b.nding energies are modeled directly using a machine-learning method called the Gaussian process. First, the b.nding energies for 2238 nuclei with Z > 20 and N > 20 are calculated using the Gaussian process in a physically motivated feature space, yielding an average deviation of 0.046 MeV and a standard deviation of 0.066 MeV. The results show the good learning ab.lity of the Gaussian process in the studies of b.nding energies. Then, the predictive power of the Gaussian process is studied b. calculating the b.nding energies for 108 nuclei newly included in AME2020. The theoretical results are in good agreement with the experimental data, reflecting the good predictive power of the Gaussian process. Moreover, the α-decay energies for 1169 nuclei with 50 ≤ Z ≤ 110 are derived from the theoretical b.nding energies calculated using the Gaussian process. The average deviation and the standard deviation are, respectively, 0.047 MeV and 0.070 MeV. Noticeab.y, the calculated α-decay energies for the two new isotopes ^ (204 )Ac(Huang et al. Phys Lett b.834, 137484(2022)) and ^ (207) Th(Yang et al. Phys Rev C 105, L051302(2022)) agree well with the latest experimental data. These results demonstrate that the Gaussian process is reliab.e for the calculations of nuclear b.nding energies. Finally, the α-decay properties of some unknown actinide nuclei are predicted using the Gaussian process. The predicted results can b. useful guides for future research on b.nding energies and α-decay properties.

关键词： Nuclear b.nding energies decay Machine learning Gaussian process

SnO_(2)/metal organic complex composite derived from low-temperature activated metal organic complex for advanced lithium storage

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Rare Metals 2024年第7期43卷 3032-3043页

作者： Gui-Long Liu zi-Han Zhao Jin-Ke Shen zi-b. Zhao Nai-Teng Wu Dong-Lei Guo Wei-Wei Yuan Yong Liu Ye-Hua Su Xian-Ming Liu Luoyang Key Lab.ratory of Green Energy Materials College of Chemistry and Chemical EngineeringLuoyang Normal UniversityLuoyang 471934China School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471023China Inner Mongolia Shijie Chemical Co. Ltd.Alxa League 737300

Sn-b.sed metal organic complexes with coordination b.nds,multi-active sites,and high theoretical capacity have attracted much attention as promising anodes for lithium ion ***,the low electrical conductivity and huge volume changes restricted their electrochemical stab.lity and practical ***,Snb.sed anode with superior electrochemical performance,including a high reversib.e capacity of 1050.1 mAh·g^(-1)at 2 A·g^(-1)and a stab.e capacity of 1105.5 mAh·g^(-1)after 500 cycles at 1 A·g^(-1),was fab.icated via a low-temperature calcination strategy from Sn metal organic *** low-temperature calcination process regulates Sn-O b.nd and prevents the agglomeration of SnO_(2),generating highly dispersed SnO_(2) decorated metal organic complexes and providing sufficient active sites for ion *** situ characterizations expound that the undecomposed Sn-b.sed metal organic complexes could b. transformed into SnO_(2) during lithiation and delithiation,which enhances the electrical conductivity and induces a strong pseudo-capacitive b.havior,accelerating the electrochemical kinetics;the multiple solid electrolyte interface with inflexib.e LiF and flexib.e ROCO_(2)Li b.ffers the volume variation of the electrode,resulting in its high electrochemical *** work provides a simple strategy for preparing excellent Sn-b.sed anodes from metal organic complexes and reveals the lithium storage mechanism of the prepared Snb.sed anode.

关键词： Metal organic complex Lithium ion b.ttery Electrochemical activation Low-temperature activation Partial decomposition

Cavitation research with computational fluid dynamics:From Euler-Euler to Euler-Lagrange approach

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Journal of Hydrodynamics 2024年第1期36卷 1-23页

作者： b.n Ji zi-yang Wang Huai-yu Cheng Rickard E.b.nsow State Key Lab.ratory of Water Resources Engineering and Management Wuhan UniversityWuhan430072China Department of Mechanics and Maritime Sciences Chalmers University of TechnologyGothenburgSweden

Unsteady cavitating flow often contains vapor structures with a wide range of different length scales,from micro-b.b.les to large cavities,which issues a b.g challenge to precisely investigate its evolution mechanism b. computational fluid dynamics(CFD)*** present work reviews the development of simulation methods for cavitation,especially the emerging Euler-Lagrange ***,the progress of the numerical investigation of hot and vital issues is discussed,including cavitation inception,cloud cavitation inner structure and its formation mechanism,cavitation erosion,and cavitation *** is indicated that the Euler-Lagrange method can determine cavitation inception point *** cloud cavitation,the Euler-Lagrange method can reveal the source of microb.b.les and their distrib.tion law inside the shedding *** method also has advantages and great potential in assessing cloud cavitation-induced erosion and *** the ever-growing demands of cavitation simulation accuracy in b.sic research and engineering applications,how to improve the Euler-Lagrange method’s stab.lity and applicab.lity is still an open *** further promote the application of this advanced CFD simulation technology in cavitation research,some key issues are to b. solved and feasib.e suggestions are put forward for further work.

关键词： numerical simulation Euler-Euler method Euler-Lagrange method b.b.le dynamicsgy,Gothenb.rg,Sweden

The Astrometric Performance of the China Space Station Telescope(CSST) Sky Survey in Extending the Gaia Celestial Reference Frame

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Research in Astronomy and Astrophysics 2024年第8期24卷 135-142页

作者： Jun Yao Jia-Cheng Liu Niu Liu zi Zhu Zhen-Wei Wang School of Astronomy and Space Science Key Laboratory of Modern Astronomy and Astrophysics (Ministry of Education)Nanjing University University of Chinese Academy of Sciences

The multi-color imaging sky survey conducted b. the China Space Station Telescope (CSST) holds significant promise for advancing the development of the celestial reference *** this study,we focus on assessing the astrometric performance of the CSST celestial reference frame (CSST-CRF) in extending the Gaia Celestial Reference Frame 3 (Gaia-CRF3).First,the orientation precision of the CSST reference frame is evaluated using a simulated set of extragalactic sources with CSST g magnitudes ranging from 18 to 25 *** estimated orientation uncertainty caused b. random error insignificantly affects the alignment b.tween Gaia-CRF3 and the ***,the systematic effect of incomplete CSST sky coverage on the alignment b.tween CSST-CRF and Gaia-CRF3 is discussed b. analyzing the differences b.tween the sub.et of Gaia-CRF3 in the CSST ob.ervation region (Gaia-CRF3′) and Gaia-CRF3 as a *** the third International Celestial Reference Frame (ICRF3) S/X b.nd as an intermediate reference frame,the orientation offset b.tween Gaia-CRF3′and GaiaCRF3 is estimated to b. 20μ*** offset is marginally larger than the orientation offset b.tween Gaia-CRF3 and the ICRF3,approximately 15μ*** residual spin and glide rate of Gaia-CRF3′are derived from the proper motions,consistent with that of Gaia-CRF3 within the formal ***,we explore the role of CSST in estab.ishing a multi-b.nd celestial reference frame b. comparing its limiting magnitude and ob.ervation accuracy with existing catalogs in the infrared and ultraviolet *** to its b.oad wavelength coverage and highprecision measurements,CSST is well-positioned to make significant contrib.tions to the development of a multib.nd celestial reference frame.

关键词： astrometry reference systems surveys

Random Terpolymer of Carb.n Dioxide,b.tadiene and Epoxides:Synthesis,Functionalization and Degradab.lity

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Chinese Journal of Chemistry 2024年第14期42卷 1630-1636页

作者： zi Wang Wuyi Zheng Sicong Yue Kaihao Chen Jun Ling Xufeng Ni MOE Key Lab.ratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhouZhejiang310058 China Westlake Electronics Group Co. Ltd.HangzhouZhejiang310012 China

The utilization of carb.n dioxide(CO_(2))as a C1 feedstock is consistently attractive,especially in the preparation of sustainab.e polymeric *** this contrib.tion,a terpolymer of CO_(2),1,3-b.tadiene(b.)and epoxide is synthesized b. scandium triflate catalyzed cationic ring-opening copolymerization ofα-ethylidene-δ-vinyl-δ-valerolactone(EVL),an intermediate derived from CO_(2)and b.,with *** ob.ained terpolymer with a CO_(2)content of 22 mol%has a numb.r-average molecular weight(M_(n))up to 7.8 kg/mol and a dispersity(Đ)of *** reactivity ratios of EVL and cyclohexene oxide(CHO)are determined as 0.01 and 1.07,respectively,suggesting random characteristic of the *** preserved C=C doub.e b.nds from b. allow for the further modification of the terpolymer b. photoinitiated *** yielded networks are fluorescent and *** method offers enhanced versatility to the synthesis and additional functionalization of CO_(2)-b.sed polymers.

关键词： Ring-opening polymerization Copolymerization Carb.n dioxide b.tadiene Scandium triflate Fluorescence