Updated on 2024/04/19

写真a

 
YAMAMOTO Masakazu
 
Organization
Academic Assembly Institute of Science and Technology JOUHOU DENSHI KOUGAKU KEIRETU Associate Professor
Faculty of Engineering Department of Engineering Associate Professor
Title
Associate Professor
External link

Degree

  • 博士(理学) ( 2010.9   東北大学 )

  • 修士(理学) ( 2007.3   東北大学 )

  • 学士(理学) ( 2005.3   愛媛大学 )

Research Interests

  • applied mathematics

  • asymptotic behavior of solutions

  • nonlinear differential equations

  • functional equations

Research Areas

  • Natural Science / Mathematical analysis

Research History

  • Niigata University   Faculty of Engineering Department of Engineering   Associate Professor

    2017.4

  • Niigata University   Abolition organization Mathematical Information Division   Associate Professor

    2015.4 - 2017.3

Professional Memberships

 

Papers

  • Optimal estimates for far field asymptotics of solutions to the quasi-geostrophic equation Reviewed

    Masakazu Yamamoto, Yuusuke Sugiyama

    Proceedings of the American Mathematical Society   149 ( 3 )   1099 - 1110   2021.1

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    Authorship:Lead author, Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:American Mathematical Society (AMS)  

    <p>The initial value problem for the two dimensional dissipative quasi-geostrophic equation of the critical and the supercritical cases is considered. Anomalous diffusion on this equation provides slow decay of solutions as the spatial parameter tends to infinity. In this paper, uniform estimates for far field asymptotics of solutions are given.</p>

    DOI: 10.1090/proc/15305

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    Other Link: https://www.ams.org/proc/earlyview/#proc15305/.pdf

  • Asymptotic stability of stationary solutions to the drift-diffusion model with the fractional dissipation Reviewed

    Yuusuke Sugiyama, Masakazu Yamamoto

    Journal of Evolution Equations   21 ( 2 )   1383 - 1417   2020.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1007/s00028-020-00628-4

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    Other Link: https://link.springer.com/article/10.1007/s00028-020-00628-4/fulltext.html

  • Spatial-decay of solutions to the quasi-geostrophic equation with the critical and supercritical dissipation Reviewed

    Masakazu Yamamoto, Yuusuke Sugiyama

    Nonlinearity   32 ( 7 )   2467 - 2480   2019.5

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    Authorship:Lead author, Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:IOP Publishing  

    DOI: 10.1088/1361-6544/ab0e5a

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    Other Link: https://iopscience.iop.org/article/10.1088/1361-6544/ab0e5a

  • Large-time asymptotics of a fractional drift–diffusion–Poisson system via the entropy method Reviewed

    Franz Achleitner, Ansgar Jüngel, Masakazu Yamamoto

    Nonlinear Analysis   179   270 - 293   2019.2

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.na.2018.08.017

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  • Asymptotic expansion of solutions to the drift–diffusion equation with fractional dissipation Reviewed

    Masakazu Yamamoto, Yuusuke Sugiyama

    Nonlinear Analysis: Theory, Methods &amp; Applications   141   57 - 87   2016.8

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    Authorship:Lead author, Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)   Publisher:Elsevier BV  

    DOI: 10.1016/j.na.2016.03.021

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  • Asymptotic Behavior of Solutions to the Drift-Diffusion Equation with Critical Dissipation Reviewed

    Masakazu Yamamoto, Yuusuke Sugiyama

    ANNALES HENRI POINCARE   17 ( 6 )   1331 - 1352   2016.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:SPRINGER BASEL AG  

    In this paper, the initial value problem for the drift-diffusion equation which stands for a model of a semiconductor device is studied. When the dissipative effect on the drift-diffusion equation is given by the half Laplacian, the dissipation balances to the extra force term. This case is called critical. The goal of this paper is to derive decay and asymptotic expansion of the solution to the drift-diffusion equation as time variable tends to infinity.

    DOI: 10.1007/s00023-015-0428-7

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  • Asymptotic expansion of solutions to the nonlinear dissipative equation with the anomalous diffusion Reviewed

    Masakazu Yamamoto

    JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS   427 ( 2 )   1027 - 1069   2015.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    The initial-value problem for the dissipative equation with the extra-force-term is considered. The dissipative effect on this equation is given by the fractional Laplacian which describes the anomalous diffusion. The main goal of this paper is to give an estimate on the difference between solutions and their asymptotic expansion as the space and the time variables tend to infinity. Furthermore, as an application, the large-time behavior of solutions to some concrete problems are discussed. (C) 2015 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.jmaa.2015.02.025

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  • Local and global solvability and blow up for the drift-diffusion equation with the fractional dissipation in the critical space Reviewed

    Yuusuke Sugiyama, Masakazu Yamamoto, Keiichi Kato

    JOURNAL OF DIFFERENTIAL EQUATIONS   258 ( 9 )   2983 - 3010   2015.3

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    We study local and global existence and uniqueness of solutions to the drift-diffusion equation with fractional dissipation (-Delta)(theta/2). In the preceding works for some associated equations, the cases theta = 1 and theta &lt; 1 are known as critical and supercritical respectively. In the critical and supercritical cases, we may not apply the L-p-theory for semilinear equations of parabolic type used in the subcritical case 1 &lt; theta &lt;= 2. We discuss local existence with large data and global existence with small data in the Besov space B-p,q(n/p-theta) (R-n), which corresponds to the scaling invariant space of the equation. Furthermore we show that solutions can blow up in finite time if initial data is not small. (C) 2015 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.jde.2014.12.033

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  • Existence and analyticity of solutions to the drift-diffusion equation with critical dissipation Reviewed

    Masakazu Yamamoto, Keiichi Kato, Yuusuke Sugiyama

    HIROSHIMA MATHEMATICAL JOURNAL   44 ( 3 )   275 - 313   2014.11

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:HIROSHIMA UNIV, GRAD SCH SCI  

    The initial value problem for the drift-diffusion equation arising from a model of semiconductor-devices is studied. The goal in this paper is to derive wellposedness and real analyticity of solutions of the initial value problem for the drift-diffusion equation with its dissipating term A = (-Delta)(1/2). In the preceding works for some associated equations, the case corresponding to this is known as critical. In this case, the drift-diffusion equation A with L is of elliptic type, so we may not apply the L-p-theory for parabolic partial differential equations used in the case that the dissipating term is A(theta) = (-Delta)(theta/2) with 1 &lt; theta &lt;= 2.

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  • ASYMPTOTIC STABILITY OF STATIONARY SOLUTIONS TO THE DRIFT-DIFFUSION MODEL IN THE WHOLE SPACE Reviewed

    Ryo Kobayashi, Masakazu Yamamoto, Shuichi Kawashima

    ESAIM-CONTROL OPTIMISATION AND CALCULUS OF VARIATIONS   18 ( 4 )   1097 - 1121   2012.10

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:EDP SCIENCES S A  

    We study the initial value problem for the drift-diffusion model arising in semiconductor device simulation and plasma physics. We show that the corresponding stationary problem in the whole space R-n admits a unique stationary solution in a general situation. Moreover, it is proved that when n &gt;= 3, a unique solution to the initial value problem exists globally in time and converges to the corresponding stationary solution as time tends to infinity, provided that the amplitude of the stationary solution and the initial perturbation are suitably small. Also, we show the sharp decay estimate for the perturbation. The stability proof is based on the time weighted L-p energy method.

    DOI: 10.1051/cocv/2011191

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  • LARGE-TIME BEHAVIOR OF SOLUTIONS TO THE DRIFT-DIFFUSION EQUATION WITH FRACTIONAL DISSIPATION Reviewed

    Masakazu Yamamoto

    DIFFERENTIAL AND INTEGRAL EQUATIONS   25 ( 7-8 )   731 - 758   2012.7

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:KHAYYAM PUBL CO INC  

    We consider the Nernst-Planck-type drift-diffusion equation with fractional dissipation. For the initial-value problem of this equation, the well-posedness, the time-global existence, and the decay of solutions were already shown. When the dissipation operator is given by the Laplacian, the asymptotic expansion of the solution as t -&gt; infinity was obtained in a previous paper. We also derive the asymptotic expansion of the solution to the drift-diffusion equation with the fractional Laplacian.

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  • ASYMPTOTIC EXPANSION OF SOLUTIONS TO THE DISSIPATIVE EQUATION WITH FRACTIONAL LAPLACIAN Reviewed

    Masakazu Yamamoto

    SIAM JOURNAL ON MATHEMATICAL ANALYSIS   44 ( 6 )   3786 - 3805   2012

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:SIAM PUBLICATIONS  

    In this paper, the Cauchy problem for the linear dissipative equation with a potential is studied. The dissipative effect of this equation is given by the fractional Laplacian. When a dissipative equation is considered, the fractional Laplacian describes the anomalous diffusion. The main goal of this paper is to derive the large-time behavior of decaying solutions. Particularly, the estimate on the difference between solutions and their asymptotic expansion as t -&gt; infinity is given. The spatial decay of this difference is also derived. Generally speaking, when a dissipative equation with the fractional Laplacian is studied, it is difficult to obtain the asymptotic expansion of solutions with high order. The anomalous diffusion causes this difficulty. The spatial decay of the difference between solutions and their asymptotic expansion provides the asymptotic expansion with arbitrary high order. Furthermore, as an application, the large-time behavior of solutions to a nonlinear problem is discussed.

    DOI: 10.1137/120873200

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  • Spatial analyticity of solutions to the drift-diffusion equation with generalized dissipation Reviewed

    Masakazu Yamamoto

    ARCHIV DER MATHEMATIK   97 ( 3 )   261 - 270   2011.9

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:BIRKHAUSER VERLAG AG  

    We consider the Cauchy problem for the drift-diffusion equation arising from the model of semiconductor devices. We know the well-posedness, the time global existence and the decay of solutions. We show the spatial analyticity of the solution.

    DOI: 10.1007/s00013-011-0302-x

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  • Asymptotic expansion of solutions to the drift-diffusion equation with large initial data Reviewed

    Masakazu Yamamoto

    JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS   369 ( 1 )   144 - 163   2010.9

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    We consider the large-time behavior of the solution to the initial value problem for the Nernst-Planck type drift-diffusion equation in whole spaces. In the L(p)-framework, the global existence and the decay of the solution were shown. Moreover, the second-order asymptotic expansion of the solution as t -&gt; infinity was derived. We also deduce the higher-order asymptotic expansion of the solution. Especially, we discuss the contrast between the odd-dimensional case and the even-dimensional case. (C) 2010 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.jmaa.2010.02.049

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  • Asymptotic expansion of solution to the Nernst-Planck drift-diffusion equation Reviewed

    Masakazu Yamamoto

    RIMS Kokyuroku Bessatsu   B15   189 - 208   2009.12

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Kyoto University  

    CiNii Article

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  • ASYMPTOTIC BEHAVIOR OF SOLUTIONS TO DRIFT-DIFFUSION SYSTEM WITH GENERALIZED DISSIPATION Reviewed

    Takayoshi Ogawa, Masakazu Yamamoto

    MATHEMATICAL MODELS & METHODS IN APPLIED SCIENCES   19 ( 6 )   939 - 967   2009.6

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:WORLD SCIENTIFIC PUBL CO PTE LTD  

    We show the global existence and asymptotic behavior of solutions for the Cauchy problem of a nonlinear parabolic and elliptic system arising from semiconductor model. Our system has generalized dissipation given by a fractional order of the Laplacian. It is shown that the time global existence and decay of the solutions to the equation with large initial data. We also show the asymptotic expansion of the solution up to the second terms as t -&gt;infinity.

    DOI: 10.1142/S021820250900367X

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MISC

Presentations

  • Sharp estimates for spatial decay of solutions to the quasi-geostrophic equation Invited

    Yamamoto, M, Sugiyama, Y

    Critical exponent and nonlinear evolution equations 2020  2020.2 

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    Event date: 2020.2

    Language:English   Presentation type:Oral presentation (general)  

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  • Spatial decay of solutions to anomalous diffusion equation Invited

    Yamamoto, M, Sugiyama, Y

    Chemotaxis and Nonlinear Parabolic Equations  2019.11 

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    Event date: 2019.11

    Language:English   Presentation type:Oral presentation (general)  

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  • 分数冪拡散方程式の解の評価に関わる不等式について Invited

    Achleitner, F, Juengel, A, Yamamoto, M

    第29回 数理物理と微分方程式  2019.11 

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    Event date: 2019.11

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • 準地衡近似方程式の解のシャープな減衰評価について

    山本征法, 杉山裕介

    日本数学会2019年度秋季総合分科会  2019.9 

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    Event date: 2019.9

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • 準地衡近似方程式の解の時空遠方でのシャープな評価 Invited

    山本征法, 杉山裕介

    信州大学偏微分方程式研究会  2019.6 

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    Event date: 2019.6

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • 半線形分数冪拡散方程式の解の時間大域挙動について Invited

    Achleitner, F, Juengel, A, Yamamoto, M

    熊本大学応用解析セミナー  2019.6 

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    Event date: 2019.6

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • 準地衡近似方程式の解の時空遠方での挙動について Invited

    山本征法, 杉山裕介

    第10回 北海道-東北 偏微分方程式コンソーシアムセミナー  2019.1 

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    Event date: 2019.1

    Language:Japanese   Presentation type:Oral presentation (general)  

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  • Application of the entropy methods to the fractional diffusion equations Invited International conference

    Masakazu Yamamoto

    Mathematics of Schroedinger Equations and Related Topics  2019.1 

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    Event date: 2019.1

    Language:English   Presentation type:Oral presentation (general)  

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  • Asymptotic behavior of solutions to the quasi-geostrophic equation of critical and supercritical type Invited

    Masakazu Yamamoto

    2018.11 

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    Language:Japanese   Presentation type:Oral presentation (general)  

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  • 準地衡近似方程式の解の空間遠方での減衰について

    山本 征法

    日本数学会2018年度秋期総合分科会  2018.9 

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    Language:Japanese   Presentation type:Oral presentation (general)  

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  • 分数冪拡散方程式の解の空間遠方での挙動について Invited

    山本 征法

    第8回 北海道-東北 偏微分方程式コンソーシアムセミナー  2018.3 

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    Language:Japanese   Presentation type:Oral presentation (general)  

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  • Asymptotic expansion of solutions to the drift-diffusion equation with anomalous diffusion International conference

    Masakazu Yamamoto

    Equadiff 2017  2017.7 

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    Language:English   Presentation type:Oral presentation (general)  

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  • Navier-Stokes方程式の解の漸近評価について Invited

    山本 征法

    第27回 数理物理と微分方程式  2016.11 

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    Language:Japanese   Presentation type:Oral presentation (general)  

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  • 拡散冪が小さな移流拡散方程式の解の漸近展開について Invited

    山本 征法

    第26回 数理物理と微分方程式  2015.11 

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  • 超臨界型移流拡散方程式の解の時間大域挙動について Invited

    山本 征法

    応用数学セミナー  2015.7 

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  • 超臨界型移流拡散方程式の解の漸近挙動について Invited

    山本 征法

    第10回 弘前解析セミナー  2015.7 

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    Language:Japanese   Presentation type:Oral presentation (general)  

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  • Asymptotic behavior of solutions to the drift-diffusion equation with critical dissipation International conference

    Masakazu Yamamoto

    2015.7 

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    Language:English   Presentation type:Poster presentation  

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  • 臨界型移流拡散方程式の解の時間大域挙動について

    山本 征法

    常微分方程式ワークショップ 松山 2015  2015.3 

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  • 拡散の冪が小さい移流拡散方程式の解の時間大域挙動について Invited

    山本 征法

    第25回 数理物理と微分方程式  2014.11 

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  • Asymptotic behavior of solutions to the drift-diffusion equation of elliptic type Invited International conference

    山本 征法

    抽象発展方程式理論から見た偏微分方程式に関する評価方法の再考  2014.10 

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  • 臨界拡散を持つ移流拡散方程式の解の漸近挙動について Invited

    山本 征法

    第4回 室蘭非線形解析研究会  2014.10 

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    Language:Japanese   Presentation type:Oral presentation (general)  

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  • 臨界拡散を持つ移流拡散方程式の解の挙動について

    山本 征法

    日本数学会2014年度秋季総合分科会  2014.9 

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    Language:Japanese   Presentation type:Oral presentation (general)  

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  • Asymptotic profile of solutions to the drift-diffusion equation with critical dissipation Invited

    Masakazu Yamamoto

    2014.9 

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    Language:English   Presentation type:Oral presentation (general)  

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  • Large-time behavior of solutions to the drift-diffusion equation with critical dissipation International conference

    Masakazu Yamamoto

    The 39th Sapporo Symposium on Partial Differential Equations  2014.8 

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    Language:English   Presentation type:Poster presentation  

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  • Asymptotic expansion of solutions to the drift-diffusion equation with critical dissipation International conference

    Masakazu Yamamoto

    The 10th AIMS Conference on Dynamical Systems, Differential Equations and Applications  2014.7 

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Research Projects

  • 発展方程式の形状と解の時空間構造の相関について

    Grant number:19K03560

    2019.4 - 2024.3

    System name:科学研究費助成事業

    Research category:基盤研究(C)

    Awarding organization:日本学術振興会

    山本 征法

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    Grant amount:\4290000 ( Direct Cost: \3300000 、 Indirect Cost:\990000 )

    当該年度は流体方程式の解の挙動に関する研究を行った。この方程式は研究課題の核心である「方程式の形状と解の構造の関連」を捉える上で指標となるものである。具体的には、方程式の非線形項に含まれる空間非局所な作用素により、解の空間減衰の速さに宿命的な制約が生じる。つまり、このモデルは、方程式の形状が解の構造を決定する具体例の一つである。このように方程式に現れる作用素などの形状が解の構造に与える影響を明らかにしようとするのが当該研究課題の主眼である。
    当該年度の研究では、長く取り組んできた流体方程式の解の時空間構造についてまとめた。この成果については、近く査読付き学術雑誌などで発表する予定である。
    また、同じく重要な研究課題である走化性方程式の解の性質について、研究協力者である杉山裕介氏(滋賀県立大学)との研究討論を行った。その結果、空間次元と拡散の冪のバランスにより、解の時間大域挙動を決定する初期データの成分が異なることが明らかとなった。一般に、初期データが「大きい」ほど走化性方程式の解は爆発しやすいが、この「大きい」が何を意味するかが問題であった。具体的には、初期データの局所的な密度が大きいと爆発する場合と、総質量が大きければ爆発する場合があり、その違いが空間次元と拡散冪のバランスによって決定することが分かった。当該年度は対面による討論が困難な状況であったが、オンラインミーティングシステムを用いて研究討論・情報交換を行った。また、オンラインによる研究集会・セミナーに参加し、研究課題に関連する最新の研究情報を収集した。
    なお、当該年度の研究を通して、運用中の計算機システムの性能不足がしばしば問題となった。次年度の早い時期にシステムの更新を図る予定である。

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  • Asymptotic behavior of solutions to the diffusion equations with a nonlocal operator

    2015.4 - 2019.3

    System name:KAKENHI

    Awarding organization:Japan Society for the Promotion of the Science

    Masakazu Yamamoto

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    Authorship:Principal investigator  Grant type:Competitive

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  • Large-time behavior of solutions to the drift-diffusion equation

    2011.4 - 2015.3

    System name:KAKENHI

    Awarding organization:Japan Society for the Promotion of Science

    Masakazu Yamamoto

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    Authorship:Principal investigator  Grant type:Competitive

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Teaching Experience

  • 応用偏微分方程式特論

    2018
    Institution name:新潟大学

  • 基礎数理B

    2017
    -
    2021
    Institution name:新潟大学

  • 情報機器操作入門

    2017
    Institution name:新潟大学

  • 応用微分方程式特論

    2015
    Institution name:新潟大学

  • 基礎数理A II

    2015
    Institution name:新潟大学

  • 応用数理B

    2015
    -
    2022
    Institution name:新潟大学

  • 基礎数理A I

    2015
    -
    2021
    Institution name:新潟大学

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