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Construction of Resilient Functions
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作者 ZHANGJie WENQiao-yan 《Wuhan University Journal of Natural Sciences》 EI CAS 2005年第1期199-202,共4页
Bastd on the relationship between nonlinearity and resiliency of amulti-output function, we present a method for constructing noninterseeling linear codes frompacking design. Through these linear codes, we obtain n-va... Bastd on the relationship between nonlinearity and resiliency of amulti-output function, we present a method for constructing noninterseeling linear codes frompacking design. Through these linear codes, we obtain n-variable, m-output, t-resilient functionswith very high nonlinearity. Their nonlinearities are currently the best results for most of cases. 展开更多
关键词 resilient functions packing design correlation-immune functions lineatcodes
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Effects of thermo-magneto-electro nonlinearity characteristics on the stability of functionally graded piezoelectric beam
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作者 Haohao BI Bo WANG +1 位作者 Zichen DENG Shuodao WANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2020年第2期313-326,共14页
Due to the increasing interests in using functionally graded piezoelectric materials(FGPMs) in the design of advanced micro-electro-mechanical systems, it is important to understand the stability behaviors of the FGPM... Due to the increasing interests in using functionally graded piezoelectric materials(FGPMs) in the design of advanced micro-electro-mechanical systems, it is important to understand the stability behaviors of the FGPM beams. In this study, considering the effects of geometrical nonlinearity, temperature, and electricity in the constitutive relations and the effect of the magnetic field on the FGPM beam, the Euler-Bernoulli beam model is adopted, and the nonlinear governing equation of motion is derived via Hamilton's principle. A perturbation method, which can decompose the deflection into static and dynamic components, is utilized to linearize the nonlinear governing equation. Then,a dynamic stability analysis is carried out, and the approximate analytical solutions for the nonlinear frequency and boundary frequencies of the unstable region are obtained.Numerical examples are performed to verify the present analysis. The effects of the static deflection, the static load factor, the temperature change, and the magnetic field flux on the stability behaviors of the FGPM beam are discussed. From the proposed analytical solutions and numerical results, one can easily and clearly find the effects of various controlled parameters, such as geometric and physical properties of the system, on the mechanical behaviors of structures, and the conclusions are very important and useful for the design of micro-devices. 展开更多
关键词 functionally GRADED piezoelectric material(FGPM) GEOMETRICAL nonlinearity stability analysis
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Thermal Nonlinearity of Functionalized Graphene Enhanced by Gold Nanorods
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《Journal of Electrical Engineering》 2017年第4期171-180,共10页
The nonlinearity of functionalized and nonfunctionlaized graphene as well as gold nanorods were investigated using the Z-scan system with an Ar+ laser beam tuned at a wavelength of 514 nm in a CW (continuous wave) ... The nonlinearity of functionalized and nonfunctionlaized graphene as well as gold nanorods were investigated using the Z-scan system with an Ar+ laser beam tuned at a wavelength of 514 nm in a CW (continuous wave) regime that was in resonance with AuNRs (gold nanorods). Z-scan experimental study indicated that functionalized graphene had a negative nonlinear refraction with self-defocusing performance. The result concluded that gold nanorods (average length was 36 ± 3 nm, and the average diameter was 12 ± 2 nm) enhance the thermal nonlinear properties of graphene oxide materials. Gold nanorods were proved to enhance the nonlinear absorption by 50%, and there was a large enhancement on the thermal nonlinear refraction and the thermo-optical coefficient (dn/dT). It was observed that the AuFG (functionalized graphene film with gold nanorods) presented a large thermal nonlinear refraction. The value of the nonlinear refraction (nl') of FG and AuFG samples was shifted from -0.533 x 10.7 cm2/W to -2.92 x 10-7 cm2/W. There was a large enhancement in thermal refraction value that was about five factors larger than the nonlinear refraction of the host material (FG) and much larger (4 orders of magnitude) than that for AuNRs. 展开更多
关键词 functionalized graphene gold nanorods nonlinear absorption refractive index thermal nonlinearity.
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A Note on Exact Traveling Wave Solutions of the Perturbed Nonlinear Schrdinger's Equation with Kerr Law Nonlinearity 被引量:4
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作者 张再云 甘向阳 +2 位作者 余德民 张映辉 李新平 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第5期764-770,共7页
In this paper,we investigate nonlinear the perturbed nonlinear Schrdinger's equation (NLSE) with Kerr law nonlinearity given in [Z.Y.Zhang,et al.,Appl.Math.Comput.216 (2010) 3064] and obtain exact traveling soluti... In this paper,we investigate nonlinear the perturbed nonlinear Schrdinger's equation (NLSE) with Kerr law nonlinearity given in [Z.Y.Zhang,et al.,Appl.Math.Comput.216 (2010) 3064] and obtain exact traveling solutions by using infinite series method (ISM),Cosine-function method (CFM).We show that the solutions by using ISM and CFM are equal.Finally,we obtain abundant exact traveling wave solutions of NLSE by using Jacobi elliptic function expansion method (JEFEM). 展开更多
关键词 exact solutions NLSE with Kerr law nonlinearity infinite series method (ISM) Cosine-function method (CFM) Jacobi elliptic function expansion method (JEFEM)
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Large deflection response-based geometrical nonlinearity of nanocomposite structures reinforced with carbon nanotubes
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作者 S.ZGHAL A.FRIKHA F.DAMMAK 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2020年第8期1227-1250,共24页
This paper deals with the nonlinear large deflection analysis of functionally graded carbon nanotube-reinforced composite(FG-CNTRC)plates and panels using a finite element method.Based on the first-order shear deforma... This paper deals with the nonlinear large deflection analysis of functionally graded carbon nanotube-reinforced composite(FG-CNTRC)plates and panels using a finite element method.Based on the first-order shear deformation theory(FSDT),the proposed model takes into account the transverse shear deformations and incorporates the geometrical nonlinearity type.A C^0 isoparametric finite shell element is developed for the present nonlinear model with the description of large displacements and finite rotations.By adopting the extended rule of mixture,the effective material properties of FG-CNTRCs are approximated with the introduction of some efficiency parameters.Four carbon nanotube(CNT)distributions,labeled uniformly distributed(UD)-CNT,FG-VCNT,FG-O-CNT,and FG-X-CNT,are considered.The solution procedure is carried out via the Newton-Raphson incremental technique.Various numerical applications in both isotropic and CNTRC composite cases are performed to trace the potential of the present model.The effects of the CNT distributions,their volume fractions,and the geometrical characteristics on the nonlinear deflection responses of FG-CNTRC structures are highlighted via a detailed parametric study. 展开更多
关键词 carbon nanotube(CNT) functionally graded material(FGM) geometrical nonlinearity large deflection
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Terminal Angular Constraint Integrated Guidance and Control for Flexible Hypersonic Vehicle with Dead-Zone Input Nonlinearity
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作者 Hewei Zhao 《Journal of Beijing Institute of Technology》 EI CAS 2020年第4期489-503,共15页
This paper presents an integrated guidance and control model for a flexible hypersonic vehicle with terminal angular constraints.The integrated guidance and control model is bounded and the dead-zone input nonlinearit... This paper presents an integrated guidance and control model for a flexible hypersonic vehicle with terminal angular constraints.The integrated guidance and control model is bounded and the dead-zone input nonlinearity is considered in the system dynamics.The line of sight angle,line of sight angle rate,attack angle and pitch rate are involved in the integrated guidance and control system.The controller is designed with a backstepping method,in which a first order filter is employed to avoid the differential explosion.The full tuned radial basis function(RBF)neural network(NN)is used to approximate the system dynamics with robust item coping with the reconstruction errors,the exactitude model requirement is reduced in the controller design.In the last step of backstepping method design,the adaptive control with Nussbaum function is used for the unknown dynamics with a time-varying control gain function.The uniform ultimate boundedness stability of the control system is proved.The simulation results validate the effectiveness of the controller design. 展开更多
关键词 hypersonic vehicle terminal angular constraint dead-zone input nonlinearity full tuned radial basis function(RBF)neural network(NN) integrated guidance and control
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Construction of 1-Resilient Boolean Functions with Optimal Algebraic Immunity and Good Nonlinearity 被引量:6
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作者 潘森杉 傅晓彤 张卫国 《Journal of Computer Science & Technology》 SCIE EI CSCD 2011年第2期269-275,共7页
This paper presents a construction for a class of 1-resilient functions with optimal algebraic immunity on an even number of variables. The construction is based on the concatenation of two balanced functions in assoc... This paper presents a construction for a class of 1-resilient functions with optimal algebraic immunity on an even number of variables. The construction is based on the concatenation of two balanced functions in associative classes. For some n, a part of 1-resilient functions with maximum algebraic immunity constructed in the paper can achieve almost optimal nonlinearity. Apart from their high nonlinearity, the functions reach Siegenthaler's upper bound of algebraic degree. Also a class of l-resilient functions on any number n 〉 2 of variables with at least sub-optimal algebraic immunity is provided. 展开更多
关键词 stream ciphers Boolean functions 1-resilient algebraic immunity algebraic degree
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Moderately large amplitude forced vibration of sandwich functionally graded auxetic beams:an analytical approach
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作者 F.M.NASREKANI H.EIPAKCHI 《Applied Mathematics and Mechanics(English Edition)》 2026年第1期99-114,共16页
Sandwich functionally graded(FG)auxetic beams are extensively utilized in aerospace,automotive,and biomedical industries due to their excellent strength-toweight ratio,impact resistance,and tunable mechanical properti... Sandwich functionally graded(FG)auxetic beams are extensively utilized in aerospace,automotive,and biomedical industries due to their excellent strength-toweight ratio,impact resistance,and tunable mechanical properties.The integration of FG materials with auxetic structures enhances their adaptability in advanced engineering applications.However,understanding their dynamic behavior under external excitations is essential for optimal design and structural reliability.Nonlinear interactions in such structures pose significant challenges in vibration analysis,necessitating robust analytical methods.This study presents a closed-form solution for the nonlinear forced vibration analysis of sandwich FG auxetic beams,offering an accurate and efficient method for predicting their dynamic response.The beam consists of two FG face sheets with material properties varying through the thickness and a re-entrant honeycomb auxetic core with an adjustable Poisson's ratio.The governing nonlinear equations of motion are derived using the first-order shear deformation theory(FSDT),the modified Gibson model,and the von Kármán relations,formulated through Hamilton's principle.A closed-form solution is obtained via the Galerkin method and multiple-scale technique.The results demonstrate that FG layers enable control of the overweight and dynamic response amplitude,with positive power law indexes reducing weight.Comparisons with finite element results confirm the accuracy of the proposed formulation. 展开更多
关键词 functionally graded(FG)auxetic beam nonlinear forced vibration closedform solution multiple-scale method first-order shear deformation theory(FSDT)
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Constructions of vector output Boolean functions with high generalized nonlinearity
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作者 KE Pin-hui ZHANG Sheng-yuan 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2008年第2期77-81,共5页
Carlet et al. recently introduced generalized nonlinearity to measure the ability to resist the improved correlation attack of a vector output Boolean function. This article presents a construction of vector output Bo... Carlet et al. recently introduced generalized nonlinearity to measure the ability to resist the improved correlation attack of a vector output Boolean function. This article presents a construction of vector output Boolean fimctions with high generalized nonlinearity using the e-biased sample space. The relation between the resilient order and generalized nonlinearity is also discussed. 展开更多
关键词 Boolean functions correlation attack generalizednonlinearity almost resilient functions
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Construction of balanced Boolean functions with high nonlinearity, good local and global avalanche characteristics 被引量:1
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作者 Luyang LI Yujuan SUN Weiguo ZHANG 《Frontiers of Mathematics in China》 SCIE CSCD 2016年第2期339-352,共14页
Boolean functions possessing multiple cryptographic criteria play an important role in the design of symmetric cryptosystems. The following criteria for cryptographic Boolean functions are often considered: high nonl... Boolean functions possessing multiple cryptographic criteria play an important role in the design of symmetric cryptosystems. The following criteria for cryptographic Boolean functions are often considered: high nonlinearity, balancedness, strict avalanche criterion, and global avalanche characteristics. The trade-off among these criteria is a difficult problem and has attracted many researchers. In this paper, two construction methods are provided to obtain balanced Boolean functions with high nonlinearity. Besides, the constructed functions satisfy strict avalanche criterion and have good global avalanche characteristics property. The algebraic immunity of the constructed functions is also considered. 展开更多
关键词 Boolean function CRYPTOGRAPHY nonlinearity strict avalanchecriterion (SAC) global avalanche characteristics
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Constructions of highly nonlinear resilient plateaud functions
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作者 张卫国 Chen Yuan 《High Technology Letters》 EI CAS 2011年第2期220-222,共3页
The main results in this paper are to construct two classes of plateaued functions with desirable cryptographic properties. By using the Maiorana-McFarland construction, a class of highly nonlinear resilient plateaued... The main results in this paper are to construct two classes of plateaued functions with desirable cryptographic properties. By using the Maiorana-McFarland construction, a class of highly nonlinear resilient plateaued functions satisfying the propagation criterion has been obtained. Johansson,s et al' s construction is modified slightly to obtain highly nonlinear multi-output resilient plateaued functions. 展开更多
关键词 CRYPTOGRAPHY boolean functions correcting codes plateaued functions resilient functions ERROR
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The impacts of non-surgical aesthetics on the core functional triad of skin
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作者 Ruifang Han Xiang Li +5 位作者 Juntong Li Shuyu Wang Shengnan Li Junpeng Yuan Jian Zhou Bin Cui 《Journal of Dermatologic Science and Cosmetic Technology》 2025年第4期1-10,共10页
As medical cosmetic technology advances rapidly,non-surgical aesthetics(NSA)interventions have emerged as a low-trauma and highly effective approach.It integrates traditional medical cosmetic techniques with modern te... As medical cosmetic technology advances rapidly,non-surgical aesthetics(NSA)interventions have emerged as a low-trauma and highly effective approach.It integrates traditional medical cosmetic techniques with modern technology,with the goal of enhancing skin condition and facial contour swiftly.However,in the process of NSA,external stimuli can impact the skin's three core functions in maintaining equilibrium,external defense,and selfrepair,leading to the occurrence of adverse reactions.Despite a breadth of literature on treatment efficacy,there is a lack of information on the changes in skin core functions.This article reviews the impact of NSA procedures on the core functional triad of skin.Due to the numerous and complex classifications of NSA procedures,this article reviews six of the most prevalent and most reported interventions over the past decade.The objective is to furnish professionals within the domain of medical aesthetics with more efficacious methodologies for the prevention and management of adverse reactions. 展开更多
关键词 Non-surgical aesthetics Equilibrium RESILIENCE SELF-HEALING Skin functions Prevention and management
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Resilient Nonlinear MPC With a Dynamic Event-Triggered Strategy Under DoS Attacks
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作者 Shuang Shen Runqi Chai +1 位作者 Yuanqing Xia Senchun Chai 《IEEE/CAA Journal of Automatica Sinica》 2025年第3期642-644,共3页
Dear Editor,This letter deals with the stabilization of a resilient model predictive control(MPC)algorithm with a dynamic event-triggered mechanism subject to Denial-of-Service(Do S)attacks.Different from previous wor... Dear Editor,This letter deals with the stabilization of a resilient model predictive control(MPC)algorithm with a dynamic event-triggered mechanism subject to Denial-of-Service(Do S)attacks.Different from previous works,this letter is based on the designed threshold function to dynamically trigger and gives the upper bound conditions for intersampling intervals with attack and attack-free scenarios to converge. 展开更多
关键词 dynamic event triggered threshold function resilient MPC denial service attacks intersampling intervals STABILIZATION upper bound conditions resilient model predictive
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Investigating Drought Resilience in Fig Cultivars:A Comprehensive Study of Leaf Structural and Functional Characteristics
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作者 Nouha Haoudi Lahcen Hssaini +3 位作者 Jamila Bahhou Abderrahim Bentaibi Hicham Aboumadane Rachid Razouk 《Phyton-International Journal of Experimental Botany》 2025年第6期1857-1877,共21页
This study was carried out to assess plasticity to drought of 30 adult fig cultivars,based on a screening of leaf structural and functional traits under sustained deficit irrigation,corresponding to 60%of crop evapotr... This study was carried out to assess plasticity to drought of 30 adult fig cultivars,based on a screening of leaf structural and functional traits under sustained deficit irrigation,corresponding to 60%of crop evapotranspiration.All trees,three per cultivar,are planted in an ex-situ collection in Sais plain,northern Morocco.The measurements concerned leaf area,blade thickness,trichomes density,trichome hair length,stomatal density,stomatal dimensions,stomatal area index,chlorophyll concentration index,relative water content,stomatal conductance,leaf temperature,water loss in detached leaves,cuticular wax content,proline content,total phenolic compounds,and total soluble sugars.The ranking of cultivars regarding drought tolerance was established based on a two-level clustering approach,primarily relying on chlorophyll concentration index and secondarily on water status traits.Results showed significant genotypic variations for all measured traits,except phenolic compounds content.Correlations between structural and functional traits have pinpointed blade thickness and trichome hair length as the key indicators of fig drought tolerance,owing to their involvement in maintaining chlorophyll content under water stress conditions.The extent of the variations shows that fig leaf is endowed with a wide structural and functional diversity,which can give to the species potential for resilience to various environmental stresses,including drought.Among the cultivars assessed,two exotic varieties,“Kadota”and“Royal Blanck”,as well as four local cultivars,namely,“Ferqouch Jmel”,“El Qoti Labied”,“Hamra”and“Fassi”showed the highest drought plasticity level. 展开更多
关键词 Fig tree plasticity to drought leaf traits functional diversity RESILIENCE
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Flexural Nonlinear Natural Frequency Analysis of Rotational Functionally Graded Sandwich Rectangular Plates with Uniform and Inhomogeneous Pore Distributions in Thermal Environments
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作者 Dazhi Zhang Yongqiang Li 《Acta Mechanica Solida Sinica》 2025年第4期664-676,共13页
This study investigates the nonlinear dynamic properties of rotating functionally graded sandwich rectangular plates in a thermal environment.The nonlinear vibration equations for a rotating metal-ceramic functionally... This study investigates the nonlinear dynamic properties of rotating functionally graded sandwich rectangular plates in a thermal environment.The nonlinear vibration equations for a rotating metal-ceramic functionally graded sandwich rectangular plate in a thermal environment are derived using classical thin plate theory and Hamilton’s principle,considering geometric nonlinearity,temperature-dependent material properties,and power law distribution of components through the thickness.With cantilever boundary conditions,the flexural nonlinear differential equations of the rectangular sandwich plate are obtained via the Galerkin method.Since the natural vibration differential equations exhibit nonlinear characteristics,the multiscale method is employed to derive the expression for nonlinear natural frequency.An example analysis reveals how the natural frequency of a functionally graded sandwich rectangular plate varies with rotational speed and temperature.Results show that the nonlinear/linear frequency ratio increases with rotational angular velocity Ω and thickness-to-length ratio h/a,follows a cosine-like periodic pattern with the setting angle,and shows a sharp decrease followed by a rapid increase with increasing width-to-length ratio b/a.The derived analytical solutions for nonlinear frequency provide valuable insights for assessing the dynamic characteristics of functionally graded structures. 展开更多
关键词 Rectangular plate SANDWICH functionally graded material Nonlinear natural frequency Rotational motion
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Generalized spline adaptive filtering algorithm based on q-hyperbolic function
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作者 Shiwei Yun Sihai Guan +1 位作者 Chuanwu Zhang Bharat Biswal 《Journal of Automation and Intelligence》 2025年第2期125-135,共11页
Based on the superiority of adaptive filtering algorithms designed with hyperbolic function-like objective functions,this paper proposes generalized spline adaptive filtering(SAF)algorithms designed with hyperbolic fu... Based on the superiority of adaptive filtering algorithms designed with hyperbolic function-like objective functions,this paper proposes generalized spline adaptive filtering(SAF)algorithms designed with hyperbolic function-like objective functions.Specifically,a series of generalized new SAF algorithms are proposed by introducing the q-deformed hyperbolic function as the cost function,named SAF-qDHSI,SAF-qDHCO,SAFqDHTA&SAF-qDHSE algorithms,respectively.Then,the proposed algorithm is theoretically demonstrated with detailed mean convergence and computational complexity analysis;secondly,the effect of different q values on the performance of the new algorithm is verified through data simulation;the new algorithm still has better performance under the interference of Gaussian noise and non-Gaussian noise even when facing the system mutation;finally,the new algorithm is verified through the measured engineering data,and the results show that the new algorithm has better convergence and robustness compared with the existing algorithm.In conclusion,the generalized algorithm based on the new cost function proposed in this paper is more effective in nonlinear system identification. 展开更多
关键词 Nonlinear systems Spline adaptive filtering q-deformed hyperbolic functions
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The localized excitation on the Weierstrass elliptic function periodic background for the (n+1)-dimensional generalized Kadomtsev–Petviashvili equation
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作者 Qiong He Jiabin Li +1 位作者 Yunqing Yang Yongshuai Zhang 《Communications in Theoretical Physics》 2025年第11期14-21,共8页
In order to investigate physically meaning localized nonlinear waves on the periodic background defined by Weierstrass elliptic℘-function for the(n+1)-dimensional generalized Kadomtsev–Petviashvili equation by Darbou... In order to investigate physically meaning localized nonlinear waves on the periodic background defined by Weierstrass elliptic℘-function for the(n+1)-dimensional generalized Kadomtsev–Petviashvili equation by Darboux transformation,the associated linear spectral problem with the Weierstrass function as the external potential is studied by utilizing the Laméfunction.The degenerate solutions of the nonlinear waves have also been obtained by approaching the limits of the half-periodsω_(1) andω_(2) of℘(x).At the same time,the evolution and nonlinear dynamics of various nonlinear waves under different parameter regimes are systematically discussed.The findings may open avenues for related experimental investigations and potential applications in various nonlinear science domains,such as nonlinear optics and oceanography. 展开更多
关键词 nonlinear wave spectral analysis linear spectral problem Laméfunction Darboux transformation
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Nonlinear traveling wave vibration of rotating ferromagnetic functionally graded cylindrical shells under multi-physics fields
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作者 Feng LIAO Yuda HU +1 位作者 Tao YANG Xiaoman LIU 《Applied Mathematics and Mechanics(English Edition)》 2025年第10期1921-1938,I0025-I0036,共30页
The nonlinear traveling wave vibration of rotating ferromagnetic functionally graded(FG)cylindrical shells under multi-physics fields is investigated.Grounded in the Kirchhoff-Love thin shell theory,the geometric nonl... The nonlinear traveling wave vibration of rotating ferromagnetic functionally graded(FG)cylindrical shells under multi-physics fields is investigated.Grounded in the Kirchhoff-Love thin shell theory,the geometric nonlinearity is incorporated into the model,and the constitutive equations are derived.The physical parameters of functionally graded materials(FGMs),which exhibit continuous variation across the thickness gradient,are of particular interest.The nonlinear magneto-thermoelastic governing equations are derived in accord with Hamilton's principle.The nonlinear partial differential equations are discretized with the Galerkin method,and the analytical expression of traveling wave frequencies is derived with an approximate method.The accuracy of the proposed method is validated through the comparison with the results from the literature and numerical solutions.Finally,the visualization analyses are conducted to examine the effects of key parameters on the traveling wave frequencies.The results show that the factors including the power-law index,temperature,magnetic field intensity,and rotating speed have the coupling effects with respect to the nonlinear vibration behavior. 展开更多
关键词 ferromagnetic functionally graded(FG)cylindrical shell nonlinear traveling wave vibration multi-physics field approximate analytical method
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树种多样性对森林生态系统多功能性和韧性的影响
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作者 刘世荣 陈远其 +2 位作者 聂秀青 明安刚 王晖 《林业科学》 北大核心 2026年第1期1-18,共18页
生物多样性对森林生态系统功能和生态系统服务具有十分重要的影响,而不断加剧的气候变化正在严重威胁森林生物多样性及生态系统的健康和稳定性。为应对气候变化和保护生物多样性,提高森林生态系统韧性、多功能性和可持续性尤为重要。树... 生物多样性对森林生态系统功能和生态系统服务具有十分重要的影响,而不断加剧的气候变化正在严重威胁森林生物多样性及生态系统的健康和稳定性。为应对气候变化和保护生物多样性,提高森林生态系统韧性、多功能性和可持续性尤为重要。树种多样性是森林经营过程中关注的核心问题,直接影响森林生态系统的多功能性、稳定性和可持续性,是当今国内外森林生态学研究的前沿和热点。由于森林生态系统的复杂性(如类型多样、结构复杂以及对干扰和环境变化的时空动态响应),人们对树种多样性调控森林生态系统多功能性内在机理的认识还十分有限。本研究系统总结树种多样性对生态系统多功能性影响的生态学原理,包括生态位分化、资源分配与功能性状整合及拮抗、互补效应与选择效应、杠杆效应与功能冗余等;综述近年来树种多样性与生态系统多功能性的研究进展,涉及树种多样性对树木生长、林分生产力、根系及根系分泌物、土壤有机碳、土壤养分、土壤微生物和根系-土壤-微生物互作等生态过程与相关功能的影响,以及树种多样性对森林生态系统响应极端干旱、病虫害、外来物种入侵等的影响;结合经营实践,从树种选择与遗传多样性、混交与不同功能型树种组配、轮伐期调整与地力维持、景观配置与多功能性等方面提出人工林质量与生态系统多功能性协同提升的经营技术对策。最后,展望树种多样性与生态系统多功能性的未来研究趋势,探究应对气候变化与生物多样性保护相协同的近自然解决方案,以期为全球气候变化背景下森林生态系统经营,尤其是人工林多功能可持续经营提供科学依据和实践参考。 展开更多
关键词 森林 树种多样性 多功能性 韧性 功能性状 森林质量 人工林 气候变化
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城市抗震韧性设计理论与方法
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作者 谢礼立 翟长海 +1 位作者 裴顺顺 胡杰 《地震工程与工程振动》 北大核心 2026年第1期1-13,共13页
随着全球城市化的加速推进,城市地震风险防控需求日益凸显。城市防震减灾的重大需求对以工程结构地震安全为核心目标的传统抗震设计理论提出了严峻挑战。目前,城市抗震韧性设计方法在国内外尚处于空白状态。本文概述了抗震设计理论的发... 随着全球城市化的加速推进,城市地震风险防控需求日益凸显。城市防震减灾的重大需求对以工程结构地震安全为核心目标的传统抗震设计理论提出了严峻挑战。目前,城市抗震韧性设计方法在国内外尚处于空白状态。本文概述了抗震设计理论的发展历程,明确了以工程韧性为根本、以制度韧性和社会经济韧性为保障的“一根本、两保障”城市抗震韧性设计构成要素,提出了确保建筑及土木基础设施抗震安全、满足城市震后预定功能、确保城市能够快速恢复的“三目标”城市抗震韧性设计总要求,构建了包括确定城市抗震韧性目标、建筑及土木基础设施结构地震安全设计、城市工程系统震后功能验算、制定震后城市工程系统功能快速恢复的技术与策略、城市制度和经济社会抗震韧性概念设计的“五环节”城市抗震韧性设计步骤,实现了“建筑及土木基础设施-工程系统-城市系统”在韧性目标、震后功能及恢复过程三方面的协同,建立了城市抗震韧性设计理论与方法,阐明了基于抗震韧性的城市抗震设计与基于性态的结构抗震设计之间的关联,从而为实现城市抗震韧性的总目标奠定了科学与技术的基础。该设计方法为从保障建筑及单体设施结构抗震安全,向保障工程系统和城市系统震后功能及快速恢复的防灾范式转变提供理论和技术支撑,也为地震安全韧性城市的构建提供了可行途径。 展开更多
关键词 城市系统 基于韧性的城市抗震设计理论 抗震韧性目标 震后功能验算 快速恢复技术和策略 地震安全韧性城市构建
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