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Quantile Regression for Thinning-based INAR(1)Models of Time Series of Counts

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Acta Mathematicae Applicatae Sinica 2021年第2期37卷 264-277页

作者： Dan-shu SHENG De-hui Wang Kai yang zi-ang WU School of Mathematics Jilin UniversityChangchun 130012China School of Economics Liaoning UniversityShenyang 110036China School of Mathematics and Statistics Changchun University of TechnologyChangchun 130012China

In this paper,we develop the quantile regression(QR)estimation for the first-order integer-valued autoregressive(INAR(1))models by defining the smoothing INAR(1)*** method is used to derive the QR estimators for the autoregressive coefficient and the quantile of *** consistency and asymptotic normality of the proposed estimators are *** performances of the proposed estimation procedures are evaluated by Monte Carlo *** results show that the proposed procedures perform well for simulations and a real data application.

关键词： INAR(1)process quantile regression parameter estimation jittering

Gradient Structured Copper by Rotationally Accelerated Shot Peening

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Journal of Materials Science & Technology 2017年第7期33卷 758-761页

作者： X.Wang Y.S.Li Q.z.ang Y.H.zhao Y.T.zhu Nano Structural Materials Center School of Materials Science and Engineering Nanjing University of Science and Technology Nanjing 210094 China School of Mechanical Engineering Nanjing University of Science and Technology Nanjing 210094 China Department of Materials Science and Engineering North Carolina State University Raleigh NC 27695 USA

A new technology-rotationally accelerated shot peening（RASP）, was developed to prepare gradient structured materials. By using centrifugal acceleration principle and large steel balls, the RASP technology can produce much higher impact energy compared to conventional shot peening. As a proof-of-concept demonstration, the RASP was utilized to refine the surface layer in pure copper（Cu） with an average grain size of 85 nm. The grain size increases largely from surface downwards the bulk, forming an800 ？m thick gradient-structured surface layer and consequently a micro-hardness gradient. The difference between the RASP technology and other established techniques in preparing gradient structured materials is discussed. The RASP technology exhibits a promoting future for large-scale manufacturing of gradient materials.

关键词： Microstructure Rotationally accelerated shot peening Gradient structure Hardness Copper

Precise asymptotics in the law of the logarithm for random fields in Hilbert space

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Journal of zhejiang University-Science A(Applied Physics & Engineering) 2007年第4期8卷 651-659页

作者： FU Ke-ang z.ang Li-xin Department of Mathematics Zhejiang University Hangzhou 310027 China

Consider the positive d-dimensional lattice z^d（d≥2） with partial ordering ≤, let {XK; K∈z＋^d} be i.i.d, random variables taking values in a real separable Hilbert space （H, ｜｜·｜｜） with mean zero and covariance operator ∑ and set partial sums SN =∑K≤nXK,K,N∈z＋^d. Under some moment conditions, we obtain the precise asymptotics of a kind of weighted infinite series for partial sums SN as ε↓ by using the truncation and approximation methods. The results are related to the convergence rates of the law of the logarithm in Hilbert space, and they also extend the results of （Gut and Spataru, 2003）.

关键词： The law of the logarithm Random field Hilbert space. Tail probabilitv. Truncation method

A weak invariance principle for self-normalized products of sums of mixing sequences

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Applied Mathematics(A Journal of Chinese Universities) 2008年第2期23卷 183-189页

作者： FU Ke-ang HUang Wei Dept. of Math. Zhejiang Univ. Hangzhou 310027 China

Let variables in the {X, Xn, n ≥ 1} be a sequence of strictly stationary φ-mixing positive random domain of attraction of the normal law. Under some suitable conditions the principle for self-normalized products of ... 详细信息

关键词： self-normalized product domain of attraction of the normal law φ-mixing Wiener process.

A Self-normalized Law of the Iterated Logarithm for the Geometrically Weighted Random Series

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Acta Mathematica Sinica,English Series 2016年第3期32卷 384-392页

作者： Ke ang FU Wei HUang School of Statistics and Mathematics Zhejiang Gongshang University Department of Mathematics Zhejiang University

Let {X, Xn; n ≥ 0} be a sequence of independent and identically distributed random variables with EX=0, and assume that EX^2I（｜X｜ ≤ x） is slowly varying as x →∞, i.e., X is in the domain of attraction of the normal law. In this paper, a self-normalized law of the iterated logarithm for the geometrically weighted random series Σ~∞（n=0）β~nXn（0 〈 β 〈 1） is obtained, under some minimal conditions.

关键词： Domain of attraction of the normal law geometrically weighted series law of the iteratedlogarithm self-normalization slowly varying

Seismic fragility analysis of highway bridges considering multi-dimensional performance limit state

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Earthquake Engineering and Engineering Vibration 2012年第2期11卷 185-193页

作者： Wang, Qi'ang Wu, ziyan Liu, Shukui School of Mechanics Civil Engineering and Architecture Northwestern Polytechnical University Xi'an 710129 China School of Mechanics Civil Engineering and Architecture Chang'an Campus of Northwestern Polytechnical University 883# mailbox Xi'an 710129 China

Fragility analysis for highway bridges has become increasingly important in the risk assessment of highway transportation networks exposed to seismic hazards. This study introduces a methodology to calculate fragility that considers multi-dimensional performance limit state parameters and makes a first attempt to develop fragility curves for a multi-span continuous (MSC) concrete girder bridge considering two performance limit state parameters: column ductility and transverse deformation in the abutments. The main purpose of this paper is to show that the performance limit states, which are compared with the seismic response parameters in the calculation of fragility, should be properly modeled as randomly interdependent variables instead of deterministic quantities. The sensitivity of fragility curves is also investigated when the dependency between the limit states is different. The results indicate that the proposed method can be used to describe the vulnerable behavior of bridges which are sensitive to multiple response parameters and that the fragility information generated by this method will be more reliable and likely to be implemented into transportation network loss estimation.

关键词： highway bridge seismic hazard multi-dimensional performance limit state fragility curves sensitivity

Entropic destruction of heavy quarkonium with hyperscaling violation

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Chinese Physics C 2021年第10期45卷 47-52页

作者： ang Li zi-Qiang z.ang School of Mathematics and Physics China University of GeosciencesWuhan 430074China Key Laboratory of Quark and Lepton Physics(MOE) Central China Normal UniversityWuhan 430079China

We study the entropic destruction of heavy quarkonium in strongly coupled theories with an anisotropic scaling symmetry in time and a spatial *** consider Lifshitz and hyperscaling violation theories,which are covariant under a generalized Lifshitz scaling symmetry with the dynamical exponent z and hyperscaling violation exponentθ.It is shown that the entropic force depends on the parameters of these *** particular,increasing z decreases the entropic force,thus reducing the quarkonium dissociation,while increasingθhas the opposite effect.

关键词： QGP quarkonium dissociation AdS/CFT correspondence entropic force

Contributions of adsorption, bioreduction and desorption to uranium immobilization by extracellular polymeric substances

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Frontiers of Environmental Science & Engineering 2023年第9期17卷 125-135页

作者： Chen zhou Ermias Gebrekrstos Tesfamariam Youneng Tang ang Li Biodesign Swette Center for Environmental Biotechnology Arizona State UniversityTempeAZ 85281USA Department of Civil and Environmental Engineering FAMU-FSU College of EngineeringFlorida State UniversityTallahasseeFL 32310USA State Key Laboratory of Urban Water Resource and Environment School of EnvironmentHarbin Institute of TechnologyHarbin 150090China

Hexavalent uranium(U(VI))can be immobilized by various *** role of extracellular polymeric substances(EPS)in U(VI)immobilization has not been *** work provides a model framework to quantify the contributions of three processes involved in EPS-mediated U(VI)immobilization:adsorption,bioreduction and *** associated EPS was extracted from a pure bacterial strain,Klebsiella sp.J1,and then exposed to H_(2) and O_(2)(no bioreduction control)to immobilize U(VI)in batch experiments.U(VI)immobilization was faster when exposed to H_(2) than O_(2) and stabilized at 94%for H_(2) and 85%for O_(2),*** non-equilibrium data from the H_(2) experiments were best simulated by a kinetic model consisting of pseudo-second-order adsorption(ka=2.87×10^(−3) g EPS·(mg U)^(−1)·min^(−1)),first-order bioreduction(kb=0.112 min−1)and first-order desorption(kd=7.00×10^(−3) min^(−1))and fitted the experimental data with R^(2) of *** adsorption was dominant in the first minute of the experiments with H_(2),bioreduction was dominant from the second minute to the 50th *** 50 min,adsorption was negligible,and bioreduction was balanced by *** work also provides the first set of equilibrium data for U(VI)adsorption by EPS *** equilibrium experiments with O_(2) were well simulated by both the Langmuir isotherm and the Freundlich isotherm,suggesting multiple mechanisms involved in the interactions between U(VI)and *** thermodynamic study indicated that the adsorption of U(VI)onto EPS was endothermic,spontaneous and favorable at higher temperatures.

关键词： Adsorption Bioreduction Desorption Kinetics Isotherm Uranium

Broadband strong optical dichroism in topological Dirac semimetals with Fermi velocity anisotropy

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Chinese Physics B 2020年第7期29卷 128-134页

作者： J Lim K J A Ooi C z.ang L K ang Yee Sin ang Science Math and TechnologySingapore University of Technology and DesignSingapore School of Energy and Chemical Engineering Xiamen University MalaysiaSelangor Darul Ehsan 43900Malaysia College of Chemistry and Chemical Engineering Xiamen UniversityXiamen 361005China School of Physics University of WollongongNorthfields AvenueNew South Wales 2522Australia

Prototypical three-dimensional(3D)topological Dirac semimetals(DSMs),such as Cd3As2 and Na3Bi,contain electrons that obey a linear momentum-energy dispersion with different Fermi velocities along the three orthogonal momentum *** being extensively studied in recent years,the inherent Fermi velocity anisotropy has often been neglected in the theoretical and numerical studies of 3D *** this omission does not qualitatively alter the physics of light-driven massless quasiparticles in 3D DSMs,it does quantitatively change the optical coefficients which can lead to nontrivial implications in terms of nanophotonics and plasmonics *** we study the linear optical response of 3D DSMs for general Fermi velocity values along each *** the signature conductivity-frequency scaling,σ(ω)∝ω,of 3D Dirac fermion is well-protected from the Fermi velocity anisotropy,the linear optical response exhibits strong linear dichroism as captured by the universal extinction ratio scaling law,Λi j=(vi/v j)^2(where i=j denotes the three spatial coordinates x,y,z,and vi is the i-direction Fermi velocity),which is independent of frequency,temperature,doping,and carrier scattering *** Cd3As2 and Na3Bi3,an exceptionally strong extinction ratio larger than 15 and covering a broad terahertz window is *** findings shed new light on the role of Fermi velocity anisotropy in the optical response of Dirac semimetals and open up novel polarization-sensitive functionalities,such as photodetection and light modulation.

关键词： topological Dirac semimetal optical anisotropy linear dichroismn linear response theory