Search Results 1-20 of 7297

  • Numerical exploration of the spiral state in the pattern formation of the Swift-Hohenberg equation on a sphere

    Gotoh Fumitoshi , Generalis Sotos C. , Itano Tomoaki

    … Herein, using the Swift-Hohenberg equation as an example, we show that Li's empirical method can be successful only in particular regions of parameter space. … Tracing the state by a continuation method generated from the static state via three symmetry breakings, the spiral state may be regarded as a resonant state generated by the combination of a few degenerate unstable modes with different azimuthal wave numbers.This work has been supported in part by KAKENHI (20K04294). …

    Science and technology reports of Kansai University = 関西大学理工学研究報告 (63), 13-20, 2021-03-20

    IR  DOI 

  • Accuracy Verification for the Inhomogeneous Wave Equation Discretized by a Finite Difference Scheme on Homogeneous Cartesian Grid  [in Japanese]

    池田 友明 , IKEDA Tomoaki

    流体力学講演会/航空宇宙数値シミュレーション技術シンポジウム2020オンライン (2020年9月28日-30日. 日本航空宇宙学会 : 宇宙航空研究開発機構(JAXA)オンライン会議)形態: カラー図版あり資料番号: AA2030013008レポート番号: JAXA-SP-20-008

    宇宙航空研究開発機構特別資料: 流体力学講演会/航空宇宙数値シミュレーション技術シンポジウム2020オンライン論文集 = JAXA Special Publication: Proceedings of Fluid Dynamics Conference / Aerospace Numerical Simulation Symposium 2020 Online (JAXA-SP-20-008), 53-57, 2021-02-08

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  • Dust Explosion Characteristics near the Minimum Explosible Concentration  [in Japanese]

    Kuwana Kazunori , Kim Wookyung , Mogi Toshio , Dobashi Ritsu

    <p>粉塵爆発の下限濃度が物性値やプロセスパラメータにどのように依存するかは,安全工学上重要な問題である.本論文では,粉塵爆発の数値シミュレーションにより得た下限濃度付近の条件における爆発挙動に関する知見を報告する.粒子間の熱伝導により既燃粒子から熱を受けた未燃粒子の温度が着火温度に達することにより燃焼波が伝播するというモデルを採用し,熱伝導方程式の発熱項をデルタ関数で表した.このとき …

    Journal of Japan Society for Safety Enginennring 60(2), 101-108, 2021

    J-STAGE 

  • Asymptotic Behavior of Solutions Toward a Multiwave Pattern to the Cauchy Problem for the Dissipative Wave Equation with Partially Linearly Degenerate Flux

    Yoshida Natsumi

    … <p>We investigate the asymptotic behavior in time of solutions to the Cauchy problem for the one-dimensional dissipative wave equation where the far field states are prescribed. … When the corresponding Riemann problem admits a Riemann solution which consists of rarefaction waves and contact discontinuity, it is proved that the solution of the Cauchy problem tends toward the linear combination of the rarefaction waves and viscous contact wave as time goes to infinity. …

    Funkcialaj Ekvacioj 64(1), 49-73, 2021

    J-STAGE 

  • Role of Social Support in the Relationship Between Financial Strain and Frequency of Exercise Among Older Japanese: A 19-year Longitudinal Study

    Komazawa Yukitsugu , Murayama Hiroshi , Harata Noboru , Takami Kiyoshi , Parady Giancarlos Troncoso

    … The results of a generalized estimation equation model showed that among females, greater financial strain in the previous wave was associated with reduced frequency of exercise (b = −0.018; …

    Journal of Epidemiology 31(4), 265-271, 2021

    J-STAGE 

  • Evaluation of user dynamics created by weak ties among divided communities

    Kubo Takahiro , Takano Chisa , Aida Masaki

    <p>Flaming phenomena represent the divergence in the strength of user dynamics as created by user interactions in online social networks (OSNs). Although it has been known that flaming phenomena …

    Nonlinear Theory and Its Applications, IEICE 12(2), 157-174, 2021

    J-STAGE 

  • Predictions of Fluid-Induced Self-Excited Oscillations by the Time-Spectral CFD  [in Japanese]

    Ohshima Ryosuke , Miyaji Koji

    … A residual of the TS equation of motion of a rigid body is found to be a useful indicator to realize limit-cycle oscillations. … It is minimized by repeating the frequency update by the Newton iteration, where the gradient of the residual with respect to the frequency is obtained from the flow simulation, and the displace update by solving the TS equation of motion. …

    AEROSPACE TECHNOLOGY JAPAN, THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 20(0), 1-8, 2021

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  • Decrease of Rossby Wave Breaking Frequency over the Middle North Pacific in Boreal Summer under Global Warming in Large-Ensemble Climate Simulations

    TAKEMURA Kazuto , MUKOUGAWA Hitoshi , MAEDA Shuhei

    … <p> Future change of Rossby wave breaking (RWB) frequency over the middle North Pacific (MNP) in August and the related features of large-scale atmospheric circulation are examined using large-ensemble simulations of current and future climates with a global circulation model. … Rossby wave propagation over Eurasia and the North Pacific in mid-latitudes is also clearly reduced in the future climate, consistent with the decreased RWB frequency over the MNP. …

    Journal of the Meteorological Society of Japan. Ser. II, 2021

    J-STAGE 

  • TIME-FREQUENCY ANALYSIS AND DECAY PROPERTIES OF TSUNAMIS

    IZUMIYA Takashi

    … The distribution for the tsunami waveform observed at Susaki, Kochi Prefecture showed that variations in the natural time periods at Susaki Bay were predominant and the maximum peak of the time-varying spectrum appeared about 80 minutes after the first tsunami wave arrived. … The decay relation of the tsunamis was theoretically estimated using a wave energy equation with the rate of dissipation due to bottom friction and turbulence. …

    Journal of JSCE 9(1), 113-124, 2021

    J-STAGE 

  • Evaluation of seismic dynamic pressures acting on cylindrical tank shell:- Proposal on seismic dynamic pressures evaluation -  [in Japanese]

    KOBAYASHI Nobuyuki , OHNO Takashi

    … A sim-ple equation of motion for the seismic response of cylindrical tanks from a velocity potential flow and the shear beam approach was developed for examining combination methods of two kinds of dynamic pressures acting on the cylindrical tank shell; … The time history analyses using by the artificial seismic wave, which represent the design response spectrum in the modified seismic coefficient method, were conducted. …

    Journal of High Pressure Institute of Japan 59(1), 15-23, 2021

    J-STAGE 

  • Spin Wave Resonance in Perpendicularly Magnetized Synthetic Antiferromagnets

    Ishibashi M. , Shiota Y. , Funada S. , Moriyama T. , Ono T.

    … <p>  We report antiferromagnetic spin wave resonance in perpendicularly magnetized synthetic antiferromagnets consisting of Co/Ni multilayers and a thin Ru spacer layer. … We also theoretically derive the spin wave dispersion for the perpendicularly magnetized synthetic antiferromagnets on the basis of an equation of motion. …

    Journal of the Magnetics Society of Japan 45(2), 25-29, 2021

    J-STAGE 

  • Circuit Theory Based on New Concepts and Its Application to Quantum Theory:23. Application of Circuit Theory to Wave Phenomena in Graphene

    Sanada Hirofumi , Nagai Nobuo

    … <p>Quantum mechanical wave phenomena in semiconductor multilayer structures are described by the effective-mass Schrödinger equation. … To date, we have focused on the similarity between the effective-mass Schrödinger equation and Maxwell's equations, and we have effectively utilized transmission-line theory as a means of the analysis and design of quantum mechanical wave phenomena. …

    Journal of Signal Processing 25(2), 87-92, 2021

    J-STAGE 

  • Statistical quantification of drop deformation behaviour and breakup initiation time in high speed air flow  [in Japanese]

    KAMIYA Tomohiro , ASAHARA Makoto , MIYASAKA Takeshi , ASATO Katsuo

    … <p>In this paper, single water drop breakup in a high-speed gas flow behind shock wave, which is generated by shock tube, are repeatedly photographed under the same conditions. … The laser rupture method, which have good shock wave generation timing, is adopted. … This breakup initiation time is compared with empirical equation of initiation time. …

    Transactions of the JSME (in Japanese) 87(894), 20-00318-20-00318, 2021

    J-STAGE 

  • Secure Communication Systems Using Distributed Parameter Chaotic Synchronization  [in Japanese]

    SANO Hideki , WAKAIKI Masashi , YAGUCHI Takaharu

    … We particularly use chaotic vibration of the wave equation with van der Pol boundary condition. … We adopt chaotic vibration of the wave equation to construct the synchronization system. …

    Transactions of the Society of Instrument and Control Engineers 57(2), 78-85, 2021

    J-STAGE 

  • Envelope Detection of a Spinning Linear Radiation Pattern Based on Diode Detector Algorithm for Amplitude Modulation

    Hirano Takuichi , Yada Atsuki

    … The maximum and minimum envelopes of the spinning linear pattern indicate the semi-major and semi-minor axes, respectively, of an elliptically polarized wave. … The diode detector algorithm was applied by solving the circuit equation using the calculus of finite differences. …

    IEICE Communications Express, 2021

    J-STAGE 

  • Expression to predict the chromatic dispersion of a high-order mode in few-mode fibers

    Ohashi Masaharu , Kawasaki Tomoya , Kubota Hirokazu , Miyoshi Yuji , Nakamura Atsushi , Iida Daisuke

    … <p>A general expression for the waveguide dispersion of a propagation mode is derived from the wave equation. …

    IEICE Communications Express 10(2), 67-72, 2021

    J-STAGE 

  • A Novel Power Loss Calculation Method for Power Magnetic Components in Power Converters  [in Japanese]

    Ishikura Yuki , Hosotani Tatsuya , Yamamoto Masayoshi

    … The differences in B-H loop areas are analyzed and discussed in case of sinusoidal waveform and square wave voltage excitation. … Relying on the output results, iron loss calculation method based on square wave excitation is proposed. … Experimental results show that the proposed iron loss calculation method is accurate compared with the traditional method using Steinmetz's equation. …

    IEEJ Transactions on Fundamentals and Materials 141(1), 69-75, 2021

    J-STAGE 

  • Solitary magnetostrophic Rossby waves in spherical shells

    Hori K. , Tobias S. M. , Jones C. A.

    … The problem at the first order is found to obey a second-order ordinary differential equation, leading to a hypergeometric equation for a Malkus field and a confluent Heun equation for an electrical wire field, and is non-singular when the wave speed approaches the mean flow. … Investigating its neutral non-singular eigensolutions for different basic states, we find the evolution is described by the Korteweg-de Vries equation. …

    Journal of Fluid Mechanics (904), R3, 2020-12-10

    IR 

  • VALIDATION OF STRESS EVALUATION FORMULAS FOR A FLOATING ROOF OF OUTDOOR OIL STORAGE TANK NOTIFIED IN THE FIRE DEFENSE LAW  [in Japanese]

    MATSUI Tetsuya

    … The method of analysis is based on representation of the liquid motion by superposing the analytical solutions that satisfy the Laplace equation and the rigid wall and bottom conditions. …

    Journal of Structural and Construction Engineering (Transactions of AIJ) (778), 1575-1585, 2020-12

    J-STAGE  AIJ 

  • Time-optimal variational control of a bright matter-wave soliton

    Tang-You Huang , Jia Zhang , Jing Li , Xi Chen

    … Motivated by recent experiments, we present the time-optimal variational control of a bright matter-wave soliton trapped in the harmonic trap by manipulating the atomic interaction through Feshbach resonances. … More specifically, we first apply the variational technique to derive the motion equation for capturing the soliton's shape and, second, combine an inverse-engineering method with optimal control theory to design the scatter length for implementing time-optimal decompression. …

    Physical Review A 102(5), 053313, 2020-11-13

    IR 

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