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Trajectory prediction in pipeline form for intercepting hypersonic gliding vehicles based on LSTM

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Chinese Journal of Aeronautics 2023年第5期36卷 421-433页

作者： Lihan sun Baoqing YANG jie MA Control and Simulation Center Harbin Institute of TechnologyHarbin 150040China

The interception problem of Hypersonic Gliding Vehicles(HGVs)has been an important aspect of missile defense *** order to provide interceptors with accurate information of target trajectory,a model based on an improved Long Short-Time Memory(LSTM)network for trajectory prediction pipeline is proposed for the interception of a skip gliding hypersonic ***,for trajectory prediction required by intercepting guidance laws,the altitude,velocity and velocity direction of the target are formulated in the form of analytic functions,consisting of linear decay terms and amplitude decay sinusoidal ***,the dynamic characteristics of the model parameters are analyzed,and the target trajectory prediction pipeline is proposed with the prediction error ***,an improved LSTM network is designed to estimate parameters in a dynamically-updated manner,and estimation results are used for the calculation of the final trajectory prediction *** proposed prediction algorithm provides information on the velocity vector for midcourse guidance with the effect of prediction errors on interception taken into *** is conducted and the results show the high accuracy of the algorithm in HGVs’trajectory prediction which is conducive to increasing the interception success rate.

关键词： Hypersonic glide vehicles Long-short time memory Near space Skip glide Trajectory prediction

Observational study of land-atmosphere turbulent flux exchange over complex underlying surfaces in urban and suburban areas

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Science China Earth Sciences 2021年第7期64卷 1050-1064页

作者： jie SHA Jun ZOU Jianning sun School of Atmospheric Sciences Nanjing UniversityNanjing 210023China Joint International Research Laboratory of Atmospheric and Earth System Sciences Nanjing UniversityNanjing 210023China Jiangsu Provincial Collaborative Innovation Center of Climate Change Nanjing 210023China

Based on observation data from urban observation stations in Nanjing and Suzhou at two heights in the roughness sublayer above the canopy and observation data at three heights in the SORPES station at the Xianlin Campus of Nanjing University in a suburban area,the of land-atmosphere turbulent flux exchange and the energy balance over complex underlying surfaces were *** results indicated that in the roughness sublayer above the canopy,the nearsurface momentum flux,sensible heat flux,and latent heat flux increase with height,and the observation value of the surface albedo increases with ***,the observation value of the net radiation decreases with height,thus resulting in a change in the urban surface energy budget with *** the SORPES station in the Xianlin Campus of Nanjing University located in a hilly area,the momentum flux,sensible heat flux,and latent heat flux of the ground observation field significantly differed from those of the two heights on the tower,while the two heights on the tower were extremely *** results indicate that the flux observation over the complex underlying surface exhibits adequate local only when it is conducted at a higher altitude above the *** turbulent flux observation results at a lower altitude in urban areas are underestimated,while the turbulent flux observation results near the surface produce a large deviation over the underlying hilly complex.

关键词： Complex underlying surface Land-atmosphere exchange Turbulent flux Observation height Local representativeness

Numerical Study of New-Type Receiver with Axially-Hollow Spiral Deflector for Parabolic Trough Direct-Steam-Generation Loop of Concentrating Solar Power System

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Journal of Thermal Science 2023年第2期32卷 597-610页

作者： SHI Yaolu sun jie WEI Jinjia School of Chemical Engineering and Technology Xi'an Jiaotong UniversityXi'an 710049China Adv Energy Sci&Technol Guangdong Lab Foshan Xianhu LabXianhu Hydrogen ValleyFoshan 528200China

The thermal stress-induced deformation issue of receiver is crucial to the performance and reliability of a parabolic-trough(PT) concentrating solar power(CSP) system with the promising direct steam generation(DSG) *** objective of the present study is to propose a new-type receiver with axially-hollow spiral deflector and optimize the geometric structure to solve the above *** this end,optical-flow-thermal multi-physics coupling models have been established for the preheating,boiling and superheating sections of a typical PT-DSG *** simulation results show that our proposed new-type receiver demonstrates outstanding comprehensive *** can minimize the circumferential temperature difference through the spiral deflector while lower the flow resistance cost through the axially hollow structure at the same *** quantitatively evaluated by the temperature uniformity improvement(ε_(ΔT)) and the performance evaluation criteria(PEC),different designs are achieved based on different optimal *** ε_(ΔT)is of primary importance,the optimal design with torsional ratio of 1 is achieved,with ε_(ΔT)=25.4%,25.7%,41.5% and PEC=0.486,0.878,0.596corresponding to preheating,boiling,superheating sections,*** PEC is of primary importance,the optimal design with torsional ratio of 6-6.5 is achieved,with PEC=0.950,2.070,0.993 and ε_(ΔT)=18.2%,13.3 %,19.4% corresponding to preheating,boiling,superheating sections,respectively.

关键词： concentrating solar power parabolic though collector direct steam generation performance evaluation criteria axially-hollow spiral deflector

Existence and multiplicity of positive solutions for an elastic beam equation

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Applied Mathematics(A Journal of Chinese Universities) 2011年第3期26卷 253-264页

作者： sun yong-ping College of Electron and Information Zhejiang University of Media and Communications Hangzhou310018 China.

This paper investigates the boundary value problem for elastic beam equation of the formu″″（t） q（t）f（t, u（t）,u′（t）,u″（t）,u′″（t））, 0〈t〈1,with the boundary conditionsu=（0）=u′（1）=u″（0）=u′″（1）=0.The boundary conditions describe the deformation of an elastic beam simply supported at left and clamped at right by sliding clamps. By using Leray-Schauder nonlinear alternate, Leray-Schauder fixed point theorem and a fixed point theorem due to Avery and Peterson, we establish some results on the existence and multiplicity of positive solutions to the boundary value problem. Our results extend and improve some recent work in the literature.

关键词： Positive solution existence and multiplicity elastic beam equation fixed point theorem nonlinear alternate.

Monotone positive solution for three-point boundary value problem

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Applied Mathematics(A Journal of Chinese Universities) 2008年第3期23卷 279-285页

作者： sun yong-ping College of Electronics and Information Zhejiang University of Media and Communications Hangzhou310018 China

In this paper, the existence of monotone positive solution for the following secondorder three-point boundary value problem is studied：x″（t）＋f（t,x（t））=0,0〈t〈1,x′（0）=0,x（1）＋δx′（η）=0,where η ∈ （0, 1）, δ∈ [0, ∞）, f ∈ C（[0, 1] × [0, ∞）, [0, ∞））. Under certain growth conditions on the nonlinear term f and by using a fixed point theorem of cone expansion and compression of functional type due to Avery, Anderson and Krueger, sufficient conditions for the existence of monotone positive solution are obtained and the bounds of solution are given. At last, an example is given to illustrate the result of the paper.

关键词： three-point boundary value problem fixed point theorem monotone positive solution

Three Symmetric Positive Solutions for Second-order Nonlocal Boundary Value Problems

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Acta Mathematicae Applicatae Sinica 2011年第2期27卷 233-242页

作者： yong-ping sun College of Electron and Information Zhejiang University of Media and Communications Hangzhou 310018China

Using the Leggett-Williams fixed point theorem, we will obtain at least three symmetric positive solutions to the second-order nonlocal boundary value problem of the form u″（t）＋g（t）f（t,u（t））=0,0〈t〈1,u（0）=u（1）=∫01m（s）u（s）ds. where m ∈ L1[0 1], g ：（0, 1）→ [0, ∞） is continuous, symmetric on （0, 1） and maybe singular at t = 0 and t = 1, f： [0, 1] × [0, ∞） → [0, ∞） is continuous and f（-, x） is symmetric on [0, 1] for all x∈ [0, ∞）.

关键词： symmetric positive solution nonlocal boundary value problem fixed point theorem

Existence and iteration of monotone positive solutions for a third-order two-point boundary value problem

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Applied Mathematics(A Journal of Chinese Universities) 2008年第4期23卷 413-419页

作者： sun yong-ping School of Electronics and Information Zhejiang University of Media and Communications Hangzhou 310018 China

The existence of nondecreasing positive solutions for the nonlinear third-order twopoint boundary value problem u′″（t）＋ q（t）f（t,u（t）,u′（t）） = 0, 0 〈 t 〈 1, u（0） = u″（0） = u′（1） = 0 is studied.... 详细信息

关键词： third-order two-point boundary value problem monotone iterative method positive solution,existence iterative scheme

Uniform Boundedness of Torsion Subgroups of Linear Groups

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Acta Mathematica Sinica,English Series 2008年第2期24卷 305-310页

作者： Bin yong sun Institute of Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 P. R. China

The torsion conjecture says： for any abelian variety A defined over a number field k, the order of the torsion subgroup of A（k） is bounded by a constant C（k,d） which depends only on the number field k and the dimension d of the abelian variety. The torsion conjecture remains open in general. However, in this paper, a short argument shows that the conjecture is true for more general fields if we consider linear groups instead of abelian varieties. If G is a connected linear algebraic group defined over a field k which is finitely generated over Q,Г is a torsion subgroup of G（k）. Then the order of Г is bounded by a constant C＇（k, d） which depends only on k and the dimension d of G.

关键词： linear algebraic group finite subgroup torsion conjecture torsion subgroup

Facile synthesis of hollow Ti2Nb10O29 microspheres for high-rate anode of Li-ion batteries

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Science China Chemistry 2018年第6期61卷 670-676页

作者： yong-Gang sun Tian-Qi sun Xi-jie Lin Xian-Sen Tao Dong Zhang Chen Zeng An-Min Cao Li-Jun Wan Key Laboratory of Molecular Nanostructure and Nanotechnology and Beijing National Laboratory for Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Fine Chemicals Dalian University of Technology Dalian 116024 China College of Food Science & Technology Huazhong Agricultural University Wuhan 430070 China

Titanium niobium oxides emerge as promising anode materials with potential for applications in lithium ion batteries with high safety and high energy ***,the innate low electronic conductivity of such a composite oxide seriously limits its practical capacity,which becomes a serious concern especially when a high rate charge/discharge capability is ***,using a modified template-assisted synthesis protocol,which features an in-situ entrapment of both titanium and niobium species during the formation of polymeric microsphere followed by a pyrolysis process,we succeed in preparing hollow microspheres of titanium niobium oxide with high efficiency in structural *** used as an anode material,the structurally-controlled hollow sample delivers high reversible capacity(103.7 m A h g^(-1)at 50 C)and extraordinary cycling capability especially at high charge/discharge currents(164.7 m A h g^(-1)after 500 cycles at 10 C).

关键词： hollow microspheres Ti2Nb10O29 anode materials high rate capability Li-ion batteries