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Property of critical excitation for moment-resisting frames subjected to horizontal and vertical simultaneous ground motions

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第11期10卷 1561-1572页

作者： kohei FUJITA Izuru TAKEWAKI Department of Urban and Environmental Engineering Graduate School of Engineering Kyoto University

It has often been reported that, when building structures are subjected to near-fault earthquake ground motions, horizontal and vertical impulsive inputs may cause critical damage during the first few seconds. In practical design of building structures, however, the safety check, taking into account the effect of multi-component ground motions, is hardly conducted except the design of important structures such as high-rise buildings and nuclear power plants. Ftirthel＇more, it is not clear how the correlation of multi-component ground motions influences the actual safety of structures. In this paper, the detailed property of critical excitation is discussed in association with the relationship between the characteristics of ground motions and those of structures. The properties of various auto power spectral density （PSD） functions of the horizontal and vertical ground motions are investigated, and those of the critical cross PSD function of these two-directional ground motions are found by a devised algorithm in a feasible complex plane. A closed-form expression is derived from the critical relation of the auto PSD functions of the simultaneous inputs. This critical excitation method provides us with a new approach for earthquake-resistant design against the possible future earthquake which causes the critical damages to buildings.

关键词： Critical excitation Multi-component ground input Critical cross spectrum Coherency Simultaneous input

Blurring Boundaries and Changing University Staff:The Case of the University of Hong Kong

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Frontiers of Education in China 2015年第4期10卷 578-607页

作者： kohei TAKAGI Office of Global Education and Collaboration Bureau of Academic AffairsSophia UniversityTokyo 102-8554Japan

In the changing higher education environment,universities increasingly engage in areas outside the traditional teaching and research *** new missions extend over wide yet specialized areas,such as technological advancement,internationalization,entrepreneurship,and enhancement of teaching and *** effectively handle these areas,universities require specific talents that may not be found in conventional academic and administrative *** transformation highlights blurred boundaries between academic and non-academic spheres of the *** in the University of Hong Kong(HKU),this paper explores how the university utilizes new professionals and administrative staff in new *** interviews with university staff reveal their profiles and perceptions in evolving organizational *** examining understudied subjects in Hong Kong,it discusses implications of changing university staff and how universities may optimize their new talent.

关键词： university administration Hong Kong professional staff

Changes in serum thyroid hormone levels and thyroid gland activity of artificially maturing female Japanese eel (Anguilla japonica)

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Acta Oceanologica Sinica 2003年第1期22卷 111-122页

作者：曲宪成 Massaki Nagae Sinji Adachi kohei Yamauchi Fisheries College Shanghai Fisheries University334 Jungong RoadShanghai 200090China Faculty of Environmental Studies Course of Environmental Conservation and PlanningNagasaki University1-14 Bunkyo-machiNagasaki 852-8521Japan Department of Biology Faculty of FisheriesHokkaido University3-1-1 Minato-choHakodate 041-0821Japan

In order to evaluate the involvement of the thyroid gland in reproduction, thyroid functioning was described in female cultivated Japanese eel (Anguilla japonica) in progressive stages of sexual maturation induced by chum salmon pituitary homogenate (SPH) treatment. Serum thyroid hormones, thyroxine (T4) and triiodothyronine (T3) were also measured in each stage. Thyroid gland activity (epithelial cell height) was high before SPH injection (previtellogenic stage), further increasing at the early vitellogenic stage, thereafter decreasing to late vitellogenic and migratory nucleus stages. The profiles of both T3 and T4 changed during vitellogenesis, being high during previtellogenic and early vitellogenic stages, and subsequently declining, thus mimicking thyroid gland activity. These results suggest that the thyroid has relation with eel ovarian development during artificial maturation.

关键词： Thyroid activity thyroxine (T4) triiodothyronine (T3) Japanese eel artificial maturation

FDNet:A Deep Learning Approach with Two Parallel Cross Encoding Pathways for Precipitation Nowcasting

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Journal of Computer Science & Technology 2023年第5期38卷 1002-1020页

作者：闫碧莹杨超陈峰 kohei Takeda Changjun Wang University of Chinese Academy of Sciences Beijing 100049China Institute of Software Chinese Academy of SciencesBeijing 100190China School of Mathematical Sciences Peking UniversityBeijing 100871China Peng Cheng Laboratory Shenzhen 518052China Guiyang Academy of Information Technology Guiyang 550081China NTT DATA Corporation Tokyo 163-8001Japan NTT DATA Institute of Management Consulting Inc. Tokyo 163-8001Japan

With the goal of predicting the future rainfall intensity in a local region over a relatively short period time,precipitation nowcasting has been a long-time scientific challenge with great social and economic *** radar echo extrapolation approaches for precipitation nowcasting take radar echo images as input,aiming to generate future radar echo images by learning from the historical *** effectively handle complex and high non-stationary evolution of radar echoes,we propose to decompose the movement into optical flow field motion and morphologic *** this idea,we introduce Flow-Deformation Network(FDNet),a neural network that models flow and deformation in two parallel cross *** flow encoder captures the optical flow field motion between consecutive images and the deformation encoder distinguishes the change of shape from the translational motion of radar *** evaluate the proposed network architecture on two real-world radar echo *** model achieves state-of-the-art prediction results compared with recent *** the best of our knowledge,this is the first network architecture with flow and deformation separation to model the evolution of radar echoes for precipitation *** believe that the general idea of this work could not only inspire much more effective approaches but also be applied to other similar spatio-temporal prediction tasks.

关键词： spatio-temporal predictive learning precipitation nowcasting neural network

Robust topology optimization of multi-material lattice structures under material and load uncertainties

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Frontiers of Mechanical Engineering 2019年第2期14卷 141-152页

作者： Yu-Chin CHAN kohei SHINTANI Wei CHEN Department of Mechanical Engineering Northwestern UniversityEvanstonIL 60208USA

Enabled by advancements in multi-material additive manufacturing,lightweight lattice structures consisting of networks of periodic unit cells have gained popularity due to their extraordinary performance and wide array of *** work proposes a density-based robust topology optimization method for meso-or macroscale multi-material lattice structures under any combination of material and load *** method utilizes a new generalized material interpolation scheme for an arbitrary number of materials,and employs univariate dimension reduction and Gauss-type quadrature to quantify and propagate *** formulating the objective function as a weighted sum of the mean and standard deviation of compliance,the tradeoff between optimality and robustness can be studied and *** of a cantilever beam lattice structure under various material and load uncertainty cases exhibit the efficiency and flexibility of the *** accuracy of univariate dimension reduction is validated by comparing the results to the Monte Carlo approach.

关键词： robust topology optimization lattice structures multi-material material uncertainty load uncertainty univariate dimension reduction

Flow and geochemical modeling of drainage from Tomitaka mine,Miyazaki,Japan

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Journal of Environmental Sciences 2015年第10期27卷 130-143页

作者： kohei Yamaguchi Shingo Tomiyama Hideya Metugi Hiroyuki Ii Akira Ueda Mitsubishi Materials Corporation 1-297 KitabukuroOmiyaSaitama 330-0835Japan Mitsubishi Materials Techno Corporation 1-14-16 KudankitaChiyoda-kuTokyo 102-8205Japan Faculty of Systems Engineering Wakayama University Japan Oil Gas and Metals National Corporation Graduate School Division of Science and Engineering University of Toyama

The chemistry and flow of water in the abandoned Tomitaka mine of Miyazaki, western Japan were investigated. This mine is located in a non-ferrous metal deposit and acid mine drainage issues from it. The study was undertaken to estimate the quantities of mine drainage that needs to be treated in order to avoid acidification of local rivers, taking into account seasonal variations in rainfall. Numerical models aimed to reproduce observed water levels and fluxes and chemical variations of groundwater and mine drainage. Rock–water interactions that may explain the observed variations in water chemistry are proposed. The results show that：（1） rain water infiltrates into the deeper bedrock through a highly permeable zone formed largely by stopes that are partially filled with spoil from excavations（ore minerals and host rocks）;（2） the water becomes acidic（p H from 3 to 4） as dissolved oxygen oxidizes pyrite;（3） along the flow path through the rocks, the redox potential of the water becomes reducing, such that pyrite becomes stable and p H of the mine drainage becomes neutral; and（4） upon leaving the mine, the drainage becomes acidic again due to oxidation of pyrite in the rocks. The present numerical model with considering of the geochemical characteristics can simulate the main variations in groundwater flow and water levels in and around the Tomitaka mine, and apply to the future treatment of the mine drainage.

关键词： Mine drainage Hydrogen isotope Oxygen isotope Rock–water interaction Water movement

Fabrication of Co2Fe（Al,Si） and Co2Fe（Al,Si）/MgO on Ge（111） Substrate and Its Magnetic Properties

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Journal of Electronic Science and Technology 2019年第2期17卷 109-115页

作者： kohei Kataoka Nobuki Tezuka Masashi Matsuura Satoshi Sugimoto Graduate School of Engineering Tohoku University

We investigated the interfacial effects on magnetic properties in Co2Fe(Al,Si)/Ge (CFAS/Ge) and CFAS/MgO/Ge systems to demonstrate the effects of the interface structure on magnetic properties. CFAS and CFAS/MgO were deposited on the i-Ge(111) substrate. In-situ reflection high energy electron diffraction (RHEED) patterns showed epitaxially grown CFAS and MgO on Ge(111). According to the X-ray diffraction (XRD)φ-scan of CFAS(220), we determined that the crystallographic orientation relationships were CFAS(111)//Ge(111) and CFAS(111)//MgO(111) Ge(111). The magnetic properties were measured by the vibrating sample magnetometer (VSM) and the saturation magnetization Ms value of CFAS with 2-nm thick MgO reached the value of L21 ordered one. A uniaxial magnetic anisotropy behavior was observed both in CFAS/Ge and CFAS/MgO/Ge structures after annealing. We confirmed the behavior did not only originate from the CFAS/Ge interface but also CFAS/MgO and the ordering structure.

关键词： Co2Fe(Al,Si) full-heusler alloy magnetic anisotropy

Eigenvalues of Elliptic Systems for the Mixed Problem in Perturbations of Lipschitz Domains with Nonhomogeneous Neumann Boundary Conditions

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Journal of Partial Differential Equations 2020年第1期33卷 48-63页

作者： MIYAZAKI kohei TAYLOR Justin L. Department of Mathematics&Statistics Murray State UniversityMurrayKentuckyU.S.A

We study eigenvalues of an elliptic operator with mixed boundary conditions on very general decompositions of the *** impose nonhomogeneous conditions on the part of the boundary where the Neumann term lies in a certain Sobolev or Lp *** work compares the behavior of and gives a relationship between the eigenvalues and eigenfunctions on the unperturbed and perturbed domains,respectively.

关键词： Eigenvalues elliptic systems mixed problem perturbed domains

High Speed SRM Using Vector Control for Electric Vehicle

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CES Transactions on Electrical Machines and Systems 2020年第1期4卷 61-68页

作者： kohei Aiso Kan Akatsu Department of electrical engineering and bio science school of advanced science and engineeringWaseda UniversityTokyoJapan Yokohama National University

The high speed motor is effective to realize downsizing motor in an electric vehicle(EV).Switched Reluctance Motor(SRM)is possible to the high speed drive because the rotor structure has simple and ***,the vibration and the acoustic noise are large from the drive ***,the conventional complicated current excitation results in the difficulty of the torque controller *** overcome these problems,the vector control has been proposed for SRM ***,the vector control has not been applied to the SRM in the high speed *** this paper,the drive conditions such as switching frequency,bus voltage for driving the SRM in the high speed region are *** is shown that the proposed SRM can be driven by the vector control in the high speed region and can realize low vibration.

关键词： Switched reluctance motor Vector control high speed drive.