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Shock Formation for 2D Isentropic Euler Equations with Self-similar Variables

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Chinese Annals of Mathematics,Series B 2024年第3期45卷 349-412页

作者： Wenze su School of Mathematical Sciences Fudan UniversityShanghai 200433China

The author studies the 2D isentropic Euler equations with the ideal gas *** exhibits a set of smooth initial data that give rise to shock formation at a single point near the planar *** solutions to the 2D isentropic Euler equations are associated with non-zero vorticity at the shock and have uniform-in-time-1/3-Holder ***,these point shocks are of self-similar type and share the same profile,which is a solution to the 2D self-similar Burgers *** proof of the solutions,following the 3D construction of Buckmaster,Shkoller and Vicol(in 2023),is based on the stable 2D self-similar Burgers profile and the modulation method.

关键词： 2D isentropic Euler equations Shock formation Self-similar solution

Design and pricing of maintenance service contract based on Nash non-cooperative game approach

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Journal of Systems Engineering and Electronics 2024年第1期35卷 118-129页

作者： su Chun HUANg Kui School of Mechanical Engineering Southeast UniversityNanjing 211189China

Nowadays manufacturers are facing fierce *** from the products,providing customers with multiple maintenance options in the service contract becomes more popular,since it can help to improve customer satisfaction,and ultimately promote sales and maximize profit for the *** considering the combinations of corrective maintenance and preventive maintenance,totally three types of maintenance service contracts are ***,attractive incentive and penalty mechanisms are adopted in the *** this basis,Nash non-cooperative game is applied to analyze the revenue for both the manufacturer and customers,and so as to optimize the pricing mechanism of maintenance service contract and achieve a win-win *** experiments are *** results show that by taking into account the incentive and penalty mechanisms,the revenue can be improved for both the customers and ***,with the increase of repair rate and improvement factor in the preventive maintenance,the revenue will increase gradually for both the parties.

关键词： maintenance service contract Nash game incentive and penalty mechanism corrective maintenance preventive maintenance

Exact solutions for magnetohydrodynamic nanofluids flow and heat transfer over a permeable axisymmetric radially stretching/shrinking sheet

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Chinese Physics B 2024年第2期33卷 108-114页

作者： U.S.Mahabaleshwar g.P.Vanitha L.M.Pérez Emad H.Aly I.Pop Department of Studies in Mathematics Davangere UniversityShivagangothriDavangereIndia Departamento de F´ısica FACIUniversidad de Tarapac´aCasilla 7DAricaChile Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt Department of Mathematics Babes-Bolyai University400084 Cluj-NapocaRomania

We report on the magnetohydrodynamic impact on the axisymmetric flow of Al_(2)O_(3)/Cu nanoparticles suspended in H_(2)O past a stretched/shrinked *** the use of partial differential equations and the corresponding thermophysical characteristics of nanoparticles,the physical flow process is *** resultant nonlinear system of partial differential equations is converted into a system of ordinary differential equations using the suitable similarity *** transformed differential equations are solved *** of the magnetic parameter,solid volume fraction and stretching/shrinking parameter on momentum and temperature distribution have been analyzed and interpreted *** skin friction and Nusselt number were also *** addition,existence of dual solution was deduced for the shrinking sheet and unique solution for the stretching ***,Al_(2)O_(3)/H_(2)O nanofluid flow has better thermal conductivity on comparing with Cu/H_(2)O ***,it was found that the first solutions of the stream are stable and physically realizable,whereas those of the second ones are unstable.

关键词： magnetohydrodynamic nanofluid stretching/shrinking sheet axisymmetric flow analytical solution suction/injection

Study on viscosity mechanism of caffeine crystallization solutions Author links open overlay panel

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Particuology 2024年第8期91卷 341-350页

作者： Linjing Yu Min su School of Chemical Engineering Hebei University of TechnologyTianjin300130China

The solid-liquid viscous system formed by high viscosity crystallization solution impacts the flow and separation ***,it is very important to study the viscosity mechanism to improve viscosity and regulate crystallization,ensuring a seamless production ***,the viscosity of crystallization solution was taken as the measurement parameter of caffeine as a model *** investigated the viscosity mechanism of caffeine crystallization solutions by combining experiment and *** results indicated that the weak interactions between caffeine and water result in increased viscosity of the caffeine crystallization ***,caffeine crystals possess elongated needle-like shapes,featuring a.substantial specific surface ***,there isπ-πstacking occurring between the(200)crystal face and(110)crystal face,effectively fostering coalescence of the crystals towards the radial side of the crystal along its elongated axis,resulting in a more viscous crystallization *** results contribute to comprehending the viscosity mechanism of crystal systems and provide theoretical foundation to enhance engineering efficiency in crystallization.

关键词： Crystallization Caffeine Viscosity mechanism Molecular simulation

Towards the Jacobian Conjecture

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Algebra Colloquium 2024年第3期31卷 361-388页

作者： Yucai su Department of Mathematics Jimei UniversityXiamen 361021China School of Mathematical Sciences Tongji UniversityShanghai 200092China

We first show that if there is a counterexample to the two-dimensional Jacobian conjecture,then there exists a nonempty closed smooth affine surface in C^(2)×C^(2)satisfying various ***,we conjecture that such a.surf... 详细信息

关键词： two-dimensional Jacobian conjecture Keller maps Jacobian pairs

Non-participation of asymptomatic candidates in screening protocols reduces early diagnosis and worsens prognosis of colorectal cancer

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World Journal of gastroenterology 2024年第26期30卷 3198-3200页

作者： Sergio Pérez-Holanda Office of Regional Viceministry of Health Regional Viceministry of HealthOviedo 33005AsturiasSpain

The Aga.suma et al’s study shows that despite the evidence of the benefits of an early colorectal cancer(CRC)diagnosis,through screening in asymptomatic subjects,up to 50%of candidates reject this option and many of those affected are diagnosed later,in advanced *** efficacy of screening programs has been well-established for several years,which reduces the risk of CRC morbidity and mortality,without taking into account the test used for screening,or other ***,a significant proportion of patients remain unscreened,so understanding the factors involved,as well as the barriers of the population to adherence is the first step to possibly modify the participation *** barriers could include a full range of social and political aspects,especially the type of financial provision of each health *** Japan,health services are universal,and this advantageous situation makes it easier for citizens to access to these services,contributing to the detection of various diseases,including ***,the symptomatic CRC group had a lower early-stage diagnosis rate than the patients detected during follow-up for other comorbidities,and symptomatic and cancer screening groups showed similar early-stage diagnosis.

关键词： Colorectal neoplasms Cancer registry Diagnostic route Cancer screening Stage at diagnosis

Towards efficient strain engineering of 2D materials:A four-points bending approach for compressive strain

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Nano Research 2024年第6期17卷 5317-5325页

作者： Hao Li Félix Carrascoso Ana Borrás gloria P.Moreno Francisco J.Aparicio Ángel Barranco Andrés Castellanos gómez Campus de Cantoblanco Instituto de Ciencia de Materiales de MadridC.Sor Juana Inés de la Cruz328049 MadridSpain Nanotechnology on surfaces and Plasma Lab Instituto de Ciencia de Materiales de Sevilla(CSIC-Universidad de Sevilla).C/Americo Vespucio 49E-41092 SevilleSpain Departamento de Física Aplicada I Escuela Politécnica SuperiorUniversidad de Sevillac/Virgen deÁfrica 7E-41011 SevilleSpain

Strain engineering,as a powerful strategy to tune the optical and electrical properties of two-dimensional(2D)materials by deforming their crystal lattice,has attracted significant interest in recent years.2D materials can sustain ultra-high strains,even up to 10%,due to the lack of dangling bonds on their surface,making them ideal brittle *** remarkable mechanical resilience,together with a strong strain-tunable band structure,endows 2D materials with a broad optical and electrical response upon ***,strain engineering based on 2D materials is restricted by their nanoscale and strain quantification *** this study,we have modified a homebuilt three-points bending apparatus to transform it into a four-points bending apparatus that allows for the application of both compressive and tensile strains on 2D *** approach allows for the efficient and reproducible construction of a strain system and minimizes the buckling effect caused by the van der Waals interaction by adamantane enca.sulation *** results demonstrate the feasibility of introducing compressive strain on 2D materials and the potential for tuning their optical and physical properties through this approach.

关键词： uniaxial compressive strain polymer enca.sulation differential reflectance spectroscopy exciton tunability

A Time-Domain Numerical Simulation for Free Motion Responses of Two Ships Advancing in Head Waves

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China Ocean Engineering 2024年第3期38卷 519-530页

作者： PAN su-yong CHENg Yong School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China

The constant panel method within the framework of potential flow theory in the time domain is developed for solving the hydrodynamic interactions between two parallel ships with forward *** solving problems within a time domain framework,the free water surface needs to simultaneously satisfy both the kinematic and dynamic boundary conditions of the free water *** provides conditions for adding artificial damping *** the Runge−Kutta method to solve equations related to *** upwind differential scheme is used in the present method to deal with the convection terms on the free surface to prevent waves *** the comparison with the available experimental data and other numerical methods,the present method is proved to have good mesh convergence,and satisfactory results can be *** constant panel method is applied to calculate the hydrodynamic interaction responses of two parallel ships advancing in head *** simulations are conducted on the effects of forward speed,different longitudinal and lateral distances on the motion response of two modified Wigley ships in head *** further investigations are conducted on the effects of different ship types on the motion response.

关键词： ship motions time domain simulation forward speed different distances wave loads

BaTiO3 solid solutions co-doped with gd3+ and Eu3+:Synthesis,structural evolution and dielectric properties

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Journal of Rare Earths 2024年第10期42卷 1920-1926页

作者： R.Martínez-López M.Pérez-Labra J.A.Romero-Serrano F.R.Barrientos-Hernández M.Reyes-Pérez M.I.Valenzuela-Carrillo g.Urbano-Reyes V.E.Reyes-Cruz g.I.Dávila-Pulido Academic Area of Earth Sciences and Materials Autonomous University of Hidalgo State Metallurgy and Materials Department ESIQIE-IPNUPALM Autonomous University of Coahuila Boulevard Adolfo López Mateos S/n

In this paper,the synthesis,structural evolution,and dielectric properties of BaTiO3solid solutions codoped with rare earth elements(gd3+and Eu3+) prepared using the solid-state reaction method are *** pure precursor powders of BaCl3,TiO2,gd2O3,and Eu2O3were mixed in stoichiometric proportions,ground in an agate mortar before being uniaxially pressed at 250 MPa and sintered at 1300℃ in air atmosphere for 6 h to obtain Ba1-3xgd2xTi1-3xEu4xO3（x=0,0.0015,0.01 and0.1）.X-ray diffraction（XRD） and Rietveld's refinement results reveal the crystal phase ferroelectric tetragonal BaTiO3for the samples with x=0,0.0015 and 0.01, as well as a consistent increment in the lattice parameters caused by the *** solubility limit of gd3+and Eu3+in the BaTiO3structure is reached for the sample with x>0.01,and the orthorhombic Eu2TiO5and monoclinic BaTi2O5secondary phases were *** Raman results show the characteristic peaks of ferroelectric tetragonal BaTiO3around 716 cm-1（LO of A1 symmetry）,515 cm-1（TO of A1 symmetry）,and 305 cm-1（B1）.The maximum relative permittivity measured at 1 kHz was recorded to be 6151.8 for the sample with x=0.0015,and a decrease in the Curie temperature to 105℃ with respect to the undoped sample was *** punctual microanalysis for the samples with x=0.0015,0.01,and 0.1 reveals grains composed of Ba,Ti,O,gd,and Eu homogeneously distributed in the *** Ba/Ti ratios for samples with x=0.0015,0.01 and 0.1 are 2.86,2.91,and 0.68,respectively,indicating substitution at the Ti site for samples with x=0.0015 and 0.01 and a.substitution at the Ba site for the sample with x=0.1.

关键词： BaTiO3 Doping Europium gadolinium Rare earths Synthesis