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A multi-shot target wheel assembly for high-repetition-rate, laser-driven proton acceleration

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High Power Laser Science and Engineering 2024年第2期 91-98页

作者： J.Pe?as A.Bembibre D.Cortina-Gil L.Martín A.Reija C.Ruiz M.Seimetz A.Alejo J.Benlliure Instituto Galego de física de Altas Enerxías Universidade de Santiago de Compostela Laboratorio Láser de Aceleración y Aplicaciones RIAIDT Universidade de Santiago de Compostela Instituto Universitario de física fundamental y matemáticas y dpto.de Didáctica de la matemática y de las Ciencias Experimentales Universidad de Salamanca Instituto de Instrumentación para Imagen Molecular (I3M) CSIC-Universitat Politècnica de València

A multi-shot target assembly and automatic alignment procedure for laser–plasma proton acceleration at high repetition rate are introduced. The assembly is based on a multi-target rotating wheel capable of hosting more than 5000 targets,mounted on a 3D motorized stage to allow rapid replenishment and alignment of the target material between laser irradiations. The automatic alignment procedure consists of a detailed mapping of the impact positions at the target surface prior to the irradiation that ensures stable operation of the target, which alongside the purpose-built design of the target wheel, enables operation at rates up to 10 Hz. Stable and continuous laser-driven proton acceleration at 10 Hz is demonstrated, with observed cut-off energy stability about 15%.

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Rheological properties and concentration evolution of thickened tailings under the coupling effect of compression and shear

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 862-876页

作者： Aixiang Wu Zhenqi Wang Zhuen Ruan Raimund Bürger Shaoyong Wang yi Mo Key Laboratory of the Ministry of Education of China for High-efficient Mining and Safety of Metal Mines University of Science and Technology BeijingBeijing 100083China Shunde Innovation School University of Science and Technology BeijingFoshan 528399China CI2MA and departamento de Ingeniería matemática Facultad de Ciencias Físicas y MatemáticasUniversidad de ConcepciónCasilla 160-CConcepciónChile School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China China Railway Construction Tongguan Investment Co. Ltd.Tongling 244000China

Cemented paste backfill(CPB)is a key technology for green mining in metal mines,in which tailings thickening comprises the primary link of CPB ***,difficult flocculation and substandard concentrations of thickened tailings often *** rheological properties and concentration evolution in the thickened tailings remain ***,traditional indoor thickening experiments have yet to quantitatively characterize their rheological *** experiment of flocculation condition optimization based on the Box-Behnken design(BBD)was performed in the study,and the two response values were investigated:concentration and the mean weighted chord length(MWCL)of ***,optimal flocculation conditions were *** addition,the rheological properties and concentration evolution of different flocculant dosages and ultrafine tailing contents under shear,compression,and compression-shear coupling experimental conditions were tested and *** results show that the shear yield stress under compression and compression-shear coupling increases with the growth of compressive yield stress,while the shear yield stress increases slightly under *** order of shear yield stress from low to high under different thickening conditions is shear,compression,and compression-shear *** compression and compression-shear coupling,the concentration first rapidly increases with the growth of compressive yield stress and then slowly increases,while concentration increases slightly under *** order of concentration from low to high under different thickening conditions is shear,compression,and compression-shear ***,the evolution mechanism of the flocs and drainage channels during the thickening of the thickened tailings under different experimental conditions was revealed.

关键词： thickened tailings compression-shear coupling compressive yield stress shear yield stress concentration

A Probabilistic description of the Impact of Vaccine-Induced Immunity in the Dynamics of COVID-19 Transmission

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Open Journal of Modelling and Simulation 2024年第2期12卷 59-73页

作者： Javier Blecua Juan fernández-Recio José Manuel Gutiérrez Instituto de Ciencias de la Vid y del Vino (ICVV) CSIC-Universidad de La Rioja-Gobierno de La Rioja Logro&#241o Spain departamento de matemá ticas y Computaci&#243n Universidad de La Rioja Logro&#241o Spain

The recent outbreak of COVID-19 has caused millions of deaths worldwide and a huge societal and economic impact in virtually all countries. A large variety of mathematical models to describe the dynamics of COVID-19 transmission have been reported. Among them, Bayesian probabilistic models of COVID-19 transmission dynamics have been very efficient in the interpretation of early data from the beginning of the pandemic, helping to estimate the impact of non-pharmacological measures in each country, and forecasting the evolution of the pandemic in different potential scenarios. These models use probability distribution curves to describe key dynamic aspects of the transmission, like the probability for every infected person of infecting other individuals, dying or recovering, with parameters obtained from experimental epidemiological data. However, the impact of vaccine-induced immunity, which has been key for controlling the public health emergency caused by the pandemic, has been more challenging to describe in these models, due to the complexity of experimental data. Here we report different probability distribution curves to model the acquisition and decay of immunity after vaccination. We discuss the mathematical background and how these models can be integrated in existing Bayesian probabilistic models to provide a good estimation of the dynamics of COVID-19 transmission during the entire pandemic period.

关键词： COVID-19 Transmission Dynamics Probabilistic Model Bayesian Analysis Markov Chain Monte Carlo

A Symbolic-Numeric Approach for Parametrizing Ruled Surfaces

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Journal of Systems Science & Complexity 2020年第3期33卷 799-820页

作者： PÉREZ-DÍAZ Sonia SHEN Li-yong dpto.de física y matemáticas Universidad de Alcalá28871-Alcaláde HenaresMadridSpain School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China

This paper presents symbolic algorithms to determine whether a given surface(implicitly or parametrically defined)is a rational ruled surface and find a proper parametrization of the ruled ***,in practical applications,one has to deal with numerical objects that are given approximately,probably because they proceed from an exact data that has been perturbed under some previous measuring process or *** these numerical objects,the authors adapt the symbolic algorithms presented by means of the use of numerical *** authors develop numeric algorithms that allow to determine ruled surfaces"close"to an input(not necessarily ruled)surface,and the distance between the input and the output surface is computed.

关键词： Implicit representation numeric algorithm ruled surface standard parametrization

Solution of the Center Problem for a Class of Polynomial Differential Systems

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1685-1696页

作者： Chang Jian Liu Jaume Llibre Rafael Ramírez Valentín Ramírez School of Mathematics(Zhuhai) Sun Yat-sen UniversityZhuhai519086P.R.China departament de matemàtiques Universitat Autònoma de Barcelona08193BellaterraBarcelonaCataloniaSpain departament d’Enginyeria Informàtica i matemàtiques Universitat Rovira i VirgiliAvinguda dels Paiïsos Catalans 2643007TarragonaCataloniaSpain

Consider the polynomial differential system of degree m of the form x=-y(1+μ(a_(2)x-a_(1)y))+x(v(a_(1)x+a_(2)y)+Ω_(m-1)(x,y)),y=x(1+μ(a_(2)x-a_(1)y))+y(v(a_(1)x+a_(2)y)+Ω_(m-1)(x,y)),whereμandνare real numbers such that(μ^(2)+v^(2))(μ+v(m-2))(a_(1)^(2)+a_(2)^(2))≠m>2 andΩ_(m−1)(x,y)is a homogenous polynomial of degree m−1.A conjecture,stated in *** Equations 2019,suggests that whenν=1,this differential system has a weak center at the origin if and only if after a convenient linear change of variable(x,y)→(X,y)the system is invariant under the transformation(X,y,t)→(−X,y,−t).for every degree m we prove the extension of this conjecture to any value ofνexcept for a finite set of values ofμ.

关键词： Center problem polynomial differential system

On the Base Point Locus of Surface Parametrizations:formulas and Consequences

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Communications in Mathematics and Statistics 2022年第4期10卷 757-783页

作者： David A.Cox Sonia Pérez-Díaz J.Rafael Sendra department of Mathematics and Statistics Amherst CollegeAmherstMA 01002USA Universidad de Alcalá Dpto.de Física y Matemáticas28871 MadridSpain

This paper shows that the multiplicity of the base point locus of a projective rational surface parametrization can be expressed as the degree of the content of a univariate *** a consequence,we get a new proof of the degree formula relating the degree of the surface,the degree of the parametrization,the base point multiplicity and the degree of the rational map induced by the *** addition,we extend both formulas to the case of dominant rational maps of the projective plane and describe how the base point loci of a parametrization and its reparametrizations are *** an application of these results,we explore how the degree of a surface reparametrization is affected by the presence of base points.

关键词： Base point Hilbert-Samuel multiplicity Surface parametrization Reparametrization Parametrization degree Surface degree

Area Operators on Bergman Spaces

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1161-1176页

作者： Xiao fen LV Jordi PAU Mao fa WANG department of Mathematics Huzhou UniversityHuzhou 313000P.R.China departament de matemàtiques i Informàtica Universitat de Barcelona08007 BarcelonaCataloniaSpain School of Mathematics and Statistics Wuhan UniversityWuhan 430072P.R.China

We completely characterize the boundedness of area operators from the Bergman spaces A_(α)^(p)(Bn)to the Lebesgue spaces L^(q)(S_(n))for all 0for the case n=1,some partial results were previously obtained by Wu in[Wu,Z.:Volterra operator,area integral and Carleson measures,*** Math.,54,2487–2500(2011)].Especially,in the case qfor the area operators to be *** solve the cases left open there and extend the results to n-complex dimension.

关键词： Area operator Bergman space tent space area formula

A generalization of the half-normal distribution

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Applied Mathematics(A Journal of Chinese Universities) 2016年第4期31卷 409-424页

作者： yolanda M. Gomez Ignacio Vidal departamento de matemáticas facultad de ciencias universidad de católica del norte Antofagasta Chile instituto de matemática y física universidad de talca Chile

In this paper we introduce an extension of the half-normal distribution in order to model a great variety of non-negative data. Its hazard rate function can be decreasing or increasing, depending on its parameters. Some properties of this new distribution are presented. for example, we give a general expression for the moments and a stochastic representation. Also, the cumulative distribution function, the hazard rate function, the survival function and the quantile function can be easily evaluated. Maximum likelihood estimators can be computed by using numerical procedures. finally, a real-life dataset has been presented to illustrate its applicability.

关键词： half-normal distribution generalized half-normal distribution maximum likelihood estimate

增材制造Ti6Al4V合金的闪速等离子体电解氧化与在生理介质中的电化学行为

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Transactions of Nonferrous Metals Society of China 2024年第4期34卷 1150-1166页

作者： H.MORA-SANCHEZ C.RAMOS M.MOHEDANO B.TORRES R.ARRABAL E.MATyKINA departamento de Ingeniería Química y de Materiales Facultad de Ciencias QuímicasUniversidad Complutense de Madrid28040 MadridSpain CIdeTEC Basque Research and Technology Alliance(BRTA)Po.Miramón 19620014 Donostia-San SebastiánSpain departamento matemática Aplicada Ciencia e Ingeniería de Materiales y Tecnología ElectrónicaUniversidad Rey Juan CarlosC/Tulipán s/nMóstoles 28933MadridSpain

研究激光粉末床熔融增材制造(AM)(又称直接金属激光烧结)技术制备的Ti6Al4V合金等离子体电解氧化(PEO)处理及其电化学行为。通过短时间(<120 s)PEO处理(也称闪速PEO),在AM合金和传统合金表面制备了3~10μm厚、含Ca和P的涂层。然后在改... 详细信息

研究激光粉末床熔融增材制造(AM)(又称直接金属激光烧结)技术制备的Ti6Al4V合金等离子体电解氧化(PEO)处理及其电化学行为。通过短时间(<120 s)PEO处理(也称闪速PEO),在AM合金和传统合金表面制备了3~10μm厚、含Ca和P的涂层。然后在改良的α-MEM溶液中,通过动电位极化曲线和电化学阻抗谱(EIS)评估了合金的电化学行为。与传统合金相比,AM合金中形成了细小的层片状α显微组织和层间小尺寸的β相颗粒,这促使了火花的产生,从而促进了PEO涂层的生长。闪速PEO涂层提高了传统合金和AM合金的耐腐蚀性,最薄的涂层(<3μm)提供了高达3倍的保护。AM Ti6Al4V由于其高的晶界密度,易受局部缝隙腐蚀的影响。而即使短至35 s的闪速PEO处理也足以成功避免这种情况。

关键词：增材制造激光粉末床熔融等离子体电解氧化闪速PEO 钛缝隙腐蚀 α-MEM

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