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Stability of Inverse Problems for Ultrahyperbolic Equations

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Chinese Annals of Mathematics,Series B 2014年第4期35卷 527-556页

作者： Fikret G?LGELEYEN Masahiro yamamoto Department of Mathematics Bülent Ecevit University Zonguldak 67100 Turkey Department of Mathematical Sciences The University of Tokyo 3-8-1 Komaba Meguro Tokyo 1538914 Japan

In this paper, the authors consider inverse problems of determining a coemcient or a source term in an ultrahyperbolic equation by some lateral boundary data. the authors prove HSlder estimates which are global and lo... 详细信息

关键词： Ultrahyperbolic equation Inverse problem Stability Carleman estimate

Boundary Conditions for Combustion Field and LB Simulation of Diesel Particulate Filter

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Communications in Computational Physics 2013年第3期13卷 769-779页

作者： Kazuhiro yamamoto Department of Mechanical Science and Engineering Faculty of EngineeringNagoya UniversityFuro-choChikusa-kuNagoya464-8603 Japan

A diesel particulate filter(DPF)is a key technology to meet future emission standards of particulate matters(PM),mainly *** is generally consists of a wall-flow type filter positioned in the exhaust stream of a diesel *** is difficult to simulate the thermal flow in DPF,because we need to consider the soot deposition and combustion in the complex geometry of filter *** our previous study,we proposed an approach for the conjugate simulation of gas-solid *** is,the gas phase was simulated by the lattice Boltzmann method(LBM),coupled with the equation of heat conduction inside the solid filter ***,its numerical procedure was slightly *** this study,to reduce numerical costs,we have tested a new boundary condition with chemical equilibrium in soot combustion at the surface of filter *** on the soot oxidation rate with catalysts evaluated in experiments,the lattice Boltzmann simulation of soot combustion in the catalyzed DPF is firstly presented to consider the process in the after-treatment of diesel exhaust *** heat and mass transfer is shown to discuss the effect of catalysts.

关键词： Lattice Boltzmann method DPF heat conduction X-ray Ct multiphase flow

Effect of vanadium and chromium on the microstructural features of V–Cr–Mn–Ni spheroidal carbide cast irons

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International Journal of Minerals,Metallurgy and Materials 2014年第11期21卷 1096-1108页

作者： V.G.Efremenko K.Shimizu A.P.Cheiliakh t.V.Kozarevskaya K.Kusumoto K.yamamoto Department of Metal Science and Heat treatment of Metals Pryazovskyi State Technical UniversityMariupol 87500 Ukraine Manufacturing and Engineering Design Center Muroran Institute of TechnologyMuroran 050-8585 Japan

the objective of this investigation is to study the influence of vanadium（5.0wt%–10.0wt%） and chromium（0–9.0wt%） on the microstructure and hardness of Cr-V-Mn-Ni white cast irons with spheroidal vanadium carbides. the alloys＇ microstructural features are presented and discussed with regard to the distribution of phase elements. the structural constituents of the alloys are spheroidal VC, proeutectoid cementite, ledeburite eutectic, rosette-shaped carbide eutectic（based on M7C3）, pearlite, martensite, and austenite. their combinations and area fraction（AF） ratios are reported to be influenced by the alloys＇ chemical composition. Spheroidized VC particles are found to be sites for the nucleation of carbide eutectics. Cr and V are shown to substitute each other in the VC and M7C3 carbides, respectively. Chromium alloying leads to the formation of a eutectic（γ-Fe ＋ М7С3）, preventing the appearance of proeutectoid cementite in the structure. Vanadium and chromium are revealed to increase the total carbide fraction and the amount of austenite in the matrix. Cr is observed to play a key role in controlling the metallic matrix microstructure.

关键词： cast irons carbides microstructure vanadium chromium austenite pearlite

Precipitation of Icosahedral Quasicrystalline Phase, R-phase and Laves Phase in Ferritic Alloys

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材料热处理学报 2004年第5期25卷 229-233页

作者： Keisuke yamamoto Yoshisato Kimura Yoshinao Mishima Department of Materials Science and Engineering Tokyo Institute of Technology Yokohama JapanDepartment of Materials Science and Engineering Tokyo Institute of Technology Yokohama JapanDepartment of Materials Science and Engineering Tokyo Institute of Technology Yokohama Japan

Ferritic heat resistant steels involving precipitation of intermetallic phases have drawn a growing interest for the enhancement of creep strength, while the brittleness of the intermetallic phases may lower the toughness of the alloy. therefore, it is necessary to optimize the dispersion characteristics of the intermetallics phase through microstructural control to minimize the trade-off between the strength and toughness. the effects of -Fe matrix substructures on the precipitation sequence, morphology, dispersion characteristics, and the stability of the intermetallic phases are investigated in Fe-Cr-W-Co-Si system. the precipitates of the Si-free Fe-10Cr-l.4W-4.5Co (at%) alloy aged at 873K are the R-phase but those of the Si-added Fe-10Cr-l.4W-4.5Co-0.3Si (at%) alloy are the icosahedral quasicrystalline phase. the precipitates in both the Si-free and Si-added alloys aged at 973K are the Laves phase. Matrix of the alloys is controlled by heat treatments as to provide three types of matrix substructures; ferrite, ferrite/martensite mixture and martensite. the hardening behavior of the alloys depends on the matrix substructures and is independent of the kinds of precipitates. In the alloys with ferrite matrix, the peak of hardness during aging at 873K shifts to longer aging time in comparison with that in the alloys with lath martensite matrix which contain numbers of nucleation sites.

关键词：过渡电子扫描仪准晶体 R相拉夫斯相铁素体钢

Effect of Cold-Rolling on Precipitation Phenomena in Sensitized type 316L and 304L Austenitic Stainless Steels

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材料热处理学报 2004年第5期25卷 217-222页

作者： H.tsubakino A.yamamoto t.Yamada L.Liu M.terasawa S.Nakahigashi H.Harada GraduateSchoolofEngineering UniversityofHyogoHimejiHyogoJapan GraduateStudent UniversityofHyogoHimejiHyogoJapan JapanPowerEngineeringandInspectionCo. YokohamaKanagawaJapan Koyo-SeikoCo.Ltd. KashiwaraOsakaJapan

Precipitation phenomena in type 316L and 304L stainless steels were studied mainly by transmission electron microscopic (tEM) observations after cold-rolling ranging from 0% (as solution annealed) to 80% reduction in thickness, and then by sensitization treatment. Precipitates were identified by electron diffraction analysis and EDS analysis. Precipitates observed in sensitized 316L stainless steel were sigma and chi phases, whereas carbide and sigma were observed in sensitized 304L stainless steel. Recrystallized grains were formed in 30% cold-rolled and sensitized 304L. However, the tendency toward recrystallization in sensitized 316L was much lower than in 304L. Precipitation of sigma and chi phases was accelerated by cold-rolling and they were observed at grain boundaries in lower cold-rolling; they were also seen, in grain interiors in higher cold-rolling. Higher deformation induced partially recrystallization combined with precipitation, resulting in the formation of heterogeneous microstructures.

关键词：冷轧 316L 304L 奥氏体不锈钢 tEM

Numerical Investigation on Detonation Wave through U-bend

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Journal of thermal Science 2010年第6期19卷 540-544页

作者： Shinobu Otsuka Masaya Suzuki Makoto yamamoto Department of Mechanical Engineering Tokyo University of Science

Pulse detonation engine (PDE) is expected for a next-generation propulsion system. PDE is a promising engine that can generates power and thrust by using intermittent detonation. Promotion of deflagration to detonation transition (below DDt) is a key issue to realize this system. PDE has experimentally been investigated, and it was confirmed that detonation tubes with U-shaped bends are useful for fast DDt. However, the mechanism of DDt promotion due to U-bends has not been well clarified. In the present study, the influence of a U-bend on detona-tion wave propagation is researched with computational fluid dynamics (CFD). the numerical results show that detonation wave disappears once near the U-bend inlet and restarts after passing through it. In addition, it was found that the use of the U-bend with small channel width and curvature radius can induce fast DDt.

关键词： Detonation Deflagration to Detonation transition (DDt) U-bend Computational Fluid Dynamics

A study of optimal switching problem in limited-cycle with multiple periods

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第12期11卷 933-937页

作者： Jing SUN Hisashi yamamoto Masayuki MAtSUI Graduate School of Engineering Nagoya Institute of Technology Gokiso-cho Showa-ku Nagoya Aichi 466-8555 Japan Department of System Design Management Systems Engineering Tokyo Metropolitan University 6-6 Asahigaoka Hino Tokyo 191-0065 Japan Department of lnformatics Graduate School of lnformatics and Engineering The University of Electro-Communications 1-5-1 Chofugaoka Chofu-shi Tokyo 182-8585 Japan

In a social system or production line,the restrictions of the cost and the due-time exist in each ***,whether these restrictions are satisfied is dependent not only on the risks of this period,but also on the risks generated *** consider controlling the production process by switching the processing rate to a faster one at a given *** paper deals with the optimal switching period to minimize the total expected cost of the production *** first propose the optimal switching period model,and then the mathematic formulation of the total expectation is ***,the policy of optimal switching period is investigated in detail by numerical experiments.

关键词： Limited-cycle problem Multi-period Optimal switching period Production seat system Manufacturing line

PIV MEASUREMENtS FOR GAS FLOW UNDER GRADIENt MAGNEtIC FIELDS

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Acta Mechanica Sinica 2004年第6期20卷 591-596页

作者：阮晓东吴锋 F.yamamoto the State Key Laboratory of Fluid Power transmission and Control Zhejiang UniversityHangzhou 310027China the College of Mechanical and Energy Engineering Zhejiang UniversityHangzhou 310027China 3 Department of Mechanical Engineering Fukui UniversityFukui 910-8507Japan

Particle Image Velocimetry(PIV)techniques were developed to measure the convec- tive N_2-air flow under gradient magnetic *** velocity fields were calculated by the Minimum Quadratic Difference(MQD)algorithm and spurious vectors were eliminated by Delaunay tessellation. the N_2-air flow was measured as the magnetic flux density varying from 0～1.5 t.A strengthened vortex flow of air was observed under the condition that the magnetic field was applied,and the ve- locity of N_2 jet rose with the increase of the magnetic *** experimental results show that the magnetic force will induce a vortex flow and cause a convection flow of the air mixture when both gradients of the O_2 concentration and the magnetic field intensity exist.

关键词： PIV magnetic field magnatoaerodynamics air convection

Study of older male drivers’driving stress compared with that of young male drivers

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Journal of traffic and transportation Engineering(English Edition) 2020年第4期7卷 467-481页

作者： Yannmq Zhao toshiyuki yamamoto Ryo Kanamori Department of Civil Engineering Nagoya UniversityNagoya 464-8603Japan Institute 0f Materials and Systems for Sustainability Nagoya UniuersityNagoya 464-8603Japan Institute of Innovation for Future Society Nagoya UniversityNagoya 464-8603Japan

In this study,older male drivers’stress while driving in straight links and while proceeding through intersections is *** area network(CAN),self-reported stress(SRS),and physiological data was collected in 22.4 km-long experimental trips among older and young ***,this study finds that older drivers reported much less stress than young ***,principal components(PCs)of the physiological data demonstrate that older drivers might underrate their driving stress in entire trips,except regarding turning at ***,following other vehicles reduced older drivers’driving stress because preceding vehicles might help them control driving speed,detect the path,and prevent road *** contrast,the similar condition increased the stress level of young *** results of random effects regression models confirm that age was the significant impact factor on SRS and physiological *** examining whether the stress at intersections could affect their driving behaviors,significant difference between two age groups was found neither in turning time nor in the driving *** study also confirms that physical and mental changes with aging can negatively affect older adults’*** the relationships among stress,speed,and accidents,we suggest the provision of more driver assistance systems,training,and education and improving intersection design for older drivers.

关键词： Driving behavior Driving stress Older driver Intersection Straight road