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Multi-layer perceptron-based data-driven multiscale modelling of granular materials with a novel Frobenius norm-based internal variable

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2198-2218页

作者： Mengqi Wang y.t.Feng Shaoheng Guan tongming Qu Zienkiewicz Centre for Computational Engineering Faculty of Science and EngineeringSwansea UniversitySwanseaWalesSA18EPUK Institute of theoretical and Computational Physics Graz University of TechnologyGraz8010Austria Department of Civil and Environmental Engineering Hong Kong University of Science and TechnologyClearwater BayKowloonHong KongChina

One objective of developing machine learning(ML)-based material models is to integrate them with well-established numerical methods to solve boundary value problems(BVPs).In the family of ML models,recurrent neural networks(RNNs)have been extensively applied to capture history-dependent constitutive responses of granular materials,but these multiple-step-based neural networks are neither sufficiently efficient nor aligned with the standard finite element method(FEM).Single-step-based neural networks like the multi-layer perceptron(MLP)are an alternative to bypass the above issues but have to introduce some internal variables to encode complex loading *** this work,one novel Frobenius norm-based internal variable,together with the Fourier layer and residual architectureenhanced MLP model,is crafted to replicate the history-dependent constitutive features of representative volume element(RVE)for granular *** obtained ML models are then seamlessly embedded into the FEM to solve the BVP of a biaxial compression case and a rigid strip footing *** obtained solutions are comparable to results from the FEM-DEM multiscale modelling but achieve significantly improved *** results demonstrate the applicability of the proposed internal variable in enabling MLP to capture highly nonlinear constitutive responses of granular materials.

关键词： Granular materials History-dependence Multi-layer perceptron(MLP) Discrete element method FEM-DEM Machine learning

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Measurements on diproton emission from the break-up channels of ^(23)Al and ^(22)Mg

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Science China(Physics,Mechanics & Astronomy) 2011年第S1期54卷 18-23页

作者： tOGANO y AOI N BABA H HONDA t OKADA K HARA y IEKI K ISHIBASHI y ItOU y IWASA N KANNO S KAWABAtA t KIMURA H KONDO y KURItA K KUROKAWA M MORIGUCHI t MURAKAMI H OISHI H OtA S OZAWA A SAKURAI H SHIMOURA S SHIODA R tAKESHItA E tAKEUCHI S yAMADA K yAMADA y yASUDA y yONEDA K MOtOBAyASHI t Institute of Physical and Chemical Research (RIKEN) Wako Saitama 351-0198 Japan Department of Physics Rikkyo University Japan Institute of Physics University of Tsukuba Ibaraki Japan Department of Physics Tohoku University Japan Center for Nuclear Study (CNS) University of Tokyo Japan Department of Physics University of Tokyo Japan

two-proton relative momentum distributions from the break-up channels 23Al→p+p+21Na and 22Mg→p+p+20Ne at an energy of 60-70 A MeV have been measured together with two-proton opening angles at the projectile fragment separator beamline (RIPS) in the RIKEN Ring Cyclotron Facility. the results demonstrate the existence of diproton emission component from single-step 2He for highly excited 23Al and 22Mg.

关键词： diproton emission proton-rich nuclei 23Al and 22Mg

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Microstructural Evolution of Infrared Brazed CP-ti Using ti-Cu-Ni Brazes

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Journal of Materials Science & technology 2011年第2期27卷 131-138页

作者： C.t.Chang t.y.yeh R.K.Shiue C.S.Chang Department of Mechanical Engineering National Hualien Industrial Vocational Senior High SchoolHualien 970TaiwanChina Department of Materials Science and Engineering National Taiwan UniversityTaipei 106TaiwanChina Engineered Materials Solutions 39 Perry AvenueMS 4-1AttleboroMA 02703-2410USA

Microstructural evolution of infrared vacuum brazed CP-ti using two ti-based braze alloys,ti-15Cu-15Ni and ti-15Cu-25Ni,has been *** infrared brazed joint consisted of eutectic ti 2 Cu/ti 2 Ni intermetallic compounds and ti-rich *** eutectic ti 2 Cu/ti 2 Ni intermetallic compounds disappeared from the joint after being annealed at 900 C for 1 *** contrast,the depletion rate of both Cu and Ni from the braze alloy into CP-ti substrate at 750 C annealing was greatly decreased as compared with that annealed at 900 *** ti 2 Cu/ti 2 Ni phases were observed even if the specimen was annealed at 750 C for 15 *** the Ni content of the ti-15Cu-25Ni braze alloy is much higher than that of the ti-15Cu-15Ni alloy,the amount of eutectic ti 2 Cu/ti 2 Ni phases in ti-15Cu-25Ni brazed joint is more than that in ti-15Ci-15Ni brazed ***,similar microstructural evolution can be obtained from the infrared brazed joint annealed at various temperatures and/or time for both filler metals.

关键词： Infrared Brazing CP-ti ti-Cu-Ni fillers Microstructure

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Oxidative stress, respiratory muscle dysfunction, and potential therapeutics in chronic obstructive pulmonary disease

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Frontiers in Biology 2012年第6期7卷 506-513页

作者： Li ZUO Allison H. HALLMAN Marvin K. yOUSIF Michael t. chien Molecular Physiology and Biophysics Laboratory Department of Biological Sciences Oakland University Rochester MI 48309 USA Department of Biology Kalamazoo College Kalamazoo MI 49006 USA

Chronic obstructive pulmonary disease （COPD） is a highly relevant disorder that induces respiratory muscle dysfunction. One prevalent symptom of COPD is resistive breathing which causes respiratory muscle to significantly increase the magnitude of contractions, resulting in reactive oxygen species （ROS） formation and oxidative stress. through cellular signaling cascades, ROS activate molecules such as mitogen-activated protein kinases and nuclear factor-kB. these signaling molecules stimulate the release of cytokines which in turn cause damage to the diaphragm, involving sarcomeric disruptions. In response to COPD induced fatigue, the diaphragm undergoes a beneficial fibertype shift to type I muscle fibers, which are more resistant to hypoxia than type II fibers. the lung hyperinflation that occurs in COPD also causes intercostal muscle dysfunction, thereby exacerbating COPD symptoms. In addition, COPD is known to have a connection with heart failure, diabetes, and aging, further decreasing respiratory function. Currently, there is no cure for this disorder. Nevertheless, various potential therapeutic strategies focusing on respiratory muscle have been identified including respiratory muscle training, β2-agonist therapy, and lung volume reduction surgery. In this review, we will outline the role of COPD, oxidative stress, and related complications in respiratory muscle dysfunction.

关键词： COPD diaphragm ROS cytokine respiratory therapy

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Asymptotics for filtration of polydisperse suspension with small impurities

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Applied Mathematics and Mechanics(English Edition) 2021年第1期42卷 109-126页

作者： L.I.KUZMINA y.V.OSIPOV t.N.GORBUNOVA Department of Applied Mathematics National Research University Higher School of EconomicsMoscow 101000Russia Department of Applied Mathematics Moscow State University of Civil Engineering(National Research University)Moscow 129337Russia

A model for deep bed filtration of a polydisperse suspension with small impurities in a porous medium is *** suspended particles move with the same velocity as the carrier water and get blocked in the pore throats due to the size-exclusion mechanism of particle retention.A solution of the model in the form of a traveling wave is *** global exact solution for a multiparticle filtration with one high concentration and several low concentrations of suspended particles is obtained in an explicit *** analytic solutions for a bidisperse suspension with large and small particles are *** profiles of the retained small particles change monotony with *** global asymptotics for the filtration of a polydisperse suspension with small kinetic rates is constructed in the whole filtration zone.

关键词： deep bed filtration suspension colloid porous medium particle size distribution analytical model

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Gap solitons of spin–orbit-coupled Bose–Einstein condensates in Pt periodic potential

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Chinese Physics B 2022年第1期31卷 140-145页

作者： S Wang y H Liu t F Xu Hebei Key Laboratory of Microstructural Material Physics School of ScienceYanshan UniversityQinhuangdao 066004China School of Science Yanshan UniversityQinhuangdao 066004China

We numerically investigate the gap solitons in Bose–Einstein condensates(BECs)with spin–orbit coupling(SOC)in the parity–time(Pt)-symmetric periodic *** find that the depths and periods of the imaginary lattice have an important influence on the shape and stability of these single-peak gap solitons and double-peak gap solitons in the first band *** dynamics of these gap solitons are checked by the split-time-step Crank–Nicolson *** is proved that the depths of the imaginary part of the Pt-symmetric periodic potential gradually increase,and the gap solitons become *** the different periods of imaginary part hardly affect the stability of the gap solitons in the corresponding parameter interval.

关键词： gap solitons spin–orbit coupling Pt-symmetric periodic potential

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NUMERICAL SIMULAtION OF INDUCtION SKULL MELtING PROCESS FOR tItANIUM-ALUMINIUM BASE ALLOy

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Acta Metallurgica Sinica(English Letters) 2004年第6期17卷 928-933页

作者： Z.y.Chen L.J.Xu F.t.Kong Q.Shu y.y.Chen SchoolofMaterialsScienceandEngineering HarbinInstituteofTechnologyHarbin150001China

the mathematics model for temperature field of water-cooling copper crucible induction skull melting process was established. the program for simulating temperature field of melting process was developed with finite element method. the temperature field of the melting process for ti-47Al-2Cr-2Nb alloy was calculated. During melting period, the temperature is raised gradually along radius augmentation direction. the elements of the charge near the crucible wall are molten first. the center elements of the charge are molten last. the melting time of the center element is just that of all the charge melting. the melting time of ti-47Al-2Cr-2Nb alloy is 15min. In which, the charge was heated by low power 80kW for 9min and by high power 300kW for 6min. When melting ti-47Al-2Cr-2Nb alloy, the loading power is nearly direct proportion to melt temperature. Increasing loading power may raise melt temperature. the best melting power of ti-47Al-2Cr-2Nb alloy is 305-310kW. this is identical with the melting test and has guidance sense to the melting process of actual titanium alloy.

关键词： tiAl base alloy melting numerical simulation

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Electronic structure of GaAs/A1GaAs quantum double rings in lateral electric field

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Chinese Optics Letters 2009年第10期7卷 882-885页

作者： y.yao t.Ochiai t.Mano t.Kuroda t.Noda N.Koguchi K.Sakoda National Institute for Materials Science University of tsukuba L-NESS Universit di Milano Bicocca

A three-dimensional model of GaAs/A1GaAs quantum double rings in the lateral static electric field is investigated theoretically. the eigenvalue problem with the effective-mass approximation is solved by means of the finite-element method. the energy levels and wave functions of quantum-confined electrons and heavy holes are obtained and show an agreement with our previous theoretical and experimental studies. It is shown in the approximation of neglecting the Coulomb attraction between the electron and heavy hole that a relatively large Stark shift of exciton emission of 4 meV is attainable with an applied electric field of 0.7 kV/cm.

关键词： GaAs Electronic structure of GaAs/A1GaAs quantum double rings in lateral electric field

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Design of double negativity elastic metamaterial

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International Journal of Smart and Nano Materials 2015年第1期6卷 61-72页

作者： y.C.Su C.t.Sun School of Aeronautics and Astronautics Purdue UniversityWest Lafay

A metamaterial model that possesses simultaneously negative effective mass density and negative effective young’s modulus is proposed in this *** curves and dynamic responses of the model are *** the double negative frequency region,it is demonstrated that the phase velocity is *** addition,it was found that the band gap region of the metamaterial can be predicted accurately by taking parts of single-unit cell to analyze the steady-state *** design is also fabricated by a 3D printer.

关键词： acoustic metamaterial double negativity local resonance negative mass negative modulus

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Meshless Methods Coupled with Other Numerical Methods

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tsinghua Science and technology 2005年第1期10卷 8-15页

作者： y.t.GU G.R.LIU CentreforAdvancedComputationsinEngineeringScience(ACES) DepartmentofMechanicalEngineeringNationalUniversityofSingapore10KentRidgeCrescentSingapore119260Singapore

Meshless or mesh-free (or shorten as MFree) methods have been proposed and achieved remarkable progress over the past few years. the idea of combining MFree methods with other existing numerical techniques such as the finite element method (FEM) and the boundary element method (BEM), is naturally of great interest in many practical applications. However, the shape functions used in some MFree methods do not have the Kronecker delta function property. In order to satisfy the combined conditions of displacement compatibility, two numerical techniques, using the hybrid displacement shape function and the modified variational form, are developed and discussed in this paper. In the first technique, the original MFree shape functions are modified to the hybrid forms that possess the Kronecker delta function property. In the second technique, the displacement compatibility is satisfied via a modified variational form based on the Lagrange multiplier method. Formulations of several coupled methods are presented. Numerical exam- ples are presented to demonstrate the effectiveness of the present coupling methods.

关键词： meshless method mesh-free method finite element method boundary element method coupling method stress analysis

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