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天津科技大学学报 2004年第A2期19卷 51-57页

作者： Toshiharu Enomae Yoon-Hee Han akira Isogai Assistant Professor Paper Science Laboratory Department of Biomaterial SciencesGraduate School of Agricultural and Life SciencesThe University of TokyoJAPANPh.D. Candidate Paper Science Laboratory Department of Biomaterial SciencesGraduate School of Agricultural and Life SciencesThe University of TokyoJAPANProfessor Paper Science Laboratory Department of Biomaterial SciencesGraduate School of Agricultural and Life SciencesThe University of TokyoJAPAN

Anisotropy of paper is an important parameter of paper structure. Image analysis technique was improved for accurate fiber orientation in paper surfaces. Image analysis using Fast Fourier Transform was demonstrated to be an effective means to determine fiber orientation angle and its intensity. Binarization process of micrograph images of paper surface and precise calculation for average Fourier coefficients as an angular distribution by interpolation developed were found to improve the accuracy. This analysis method was applied to digital optical micrographs and scanning electron micrographs of paper. A laboratory handsheet showed a large deviation in the average value of fiber orientation angle, but some kinds of machine-made paper showed about 90 degrees in the orientation angle with very small deviations as expected. Korea and Japanese paper made in the traditional ways showed its own characteristic depending on its hand making processes.

关键词：各向异性方向性分布图象分析快速傅立叶变换方向性强度日本纸韩国纸纸浆纤维

Weyl points and Dirac lines protected by multiple screw rotations

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Science Bulletin 2017年第11期62卷 788-794页

作者： akira Furusaki Condensed Matter Theory Laboratory RIKEN Wako Saitama 351-0198 Japan

In three-dimensional noncentrosymmetric materials two-fold screw rotation symmetry forces electron's energy bands to have Weyl points at which two bands touch.This is illustrated for space groups No.19(P2_12_12_1) and No.198(P2_13),which have three orthogonal screw rotation axes.In the case of space groups No.61(Pbca) and No.205(Pa-3) that have extra inversion symmetry,Weyl points are promoted to fourfold degenerate line nodes in glide-invariant planes.The three-fold rotation symmetry present in the space groups No.198 and No.205 allows Weyl and Dirac points,respectively,to appear along its rotation axes in the Brillouin zone and generates four-fold and six-fold degeneracy at the C point and R point,respectively.

关键词：旋转对称性狄拉克保护螺杆非中心对称空间群布里渊区转动轴

Photocatalytic dry reforming of methane by rhodium supported monoclinic TiO_(2)-B nanobelts

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Journal of Energy Chemistry 2022年第8期31卷 562-571,I0015页

作者： Masaru Kushida akira Yamaguchi Masahiro Miyauchi School of Materials and Chemical Technology Tokyo Institute of Technology2-12-1 OokayamaMeguro-kuTokyo 152-8552Japan

The conversion of methane and carbon dioxide into syngas(dry reforming of methane;DRM)has attracted attention owing to the potential to reuse greenhouse gases.Titanium dioxide(TiO_(2))-based photocatalysts,which have been widely commercialized owing to their high efficiency,non-toxicity,and low cost,are strongly desired in DRM.Here,we report a monoclinic-phase TiO_(2)-B nanobelts-supported rhodium(Rh/TiO_(2)-B nanobelts)catalyst that efficiently promotes DRM under ultraviolet light irradiation at low temperatures.Photogenerated holes in the TiO_(2)-B nanobelts were used to oxidize methane,while the electrons were trapped in rhodium to reduce carbon dioxide.Rh/TiO_(2)-B nanobelts exhibited considerably higher durability and activity than Rh-loaded conventional TiO_(2)(anatase and rutile),owing to the lattice and/or surface oxygen reactivity in TiO_(2)-B nanobelts,which was suggested by X-ray photoelectron spectroscopy measurements and photocatalytic performance tests under an atmosphere of methane alone.This study paves the path for the effective utilization of methane by constructing active TiO_(2)-based nanometal photocatalysts.

关键词： Photocatalysis Dry reforming of methane Greenhouse gas conversion Gas-phase reaction Titanium dioxide TiO_(2)-B

Limb Stiffness Improvement of the Robot WAREC-1R for a Faster and Stable New Ladder Climbing Gait

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Journal of Bionic Engineering 2023年第1期20卷 57-68页

作者： Xiao Sun akira Ito Takashi Matsuzawa Atsuo Takanishi Department of Mechatronics University of YamanashiYamanashi400-8511Japan Faculty of Science and Engineering Waseda UniversityTokyo162-8480Japan

Ladder climbing is a relatively new but practical locomotion style for robots. Unfortunately, due to their size and weight, ladder climbing by human-sized robots developed so far is struggling with the speedup of ladder climbing motion itself. Therefore, in this paper, a new ladder climbing gait for the robot WAREC-1R is proposed by the authors, which is both faster than the former ones and stable. However, to realize such a gait, a point that has to be taken into consideration is the deformation caused by the self-weight of the robot. To deal with this issue, extra hardware (sensor) and software (position and force control) systems and extra time for sensing and calculation were required. For a complete solution without any complicated systems and time only for deformation compensation, limb stiffness improvement plan by the minimal design change of mechanical parts of the robot is also proposed by the authors, with a thorough study about deformation distribution in the robot. With redesigned parts, ladder climbing experiments by WAREC-1R proved that both the new ladder climbing gait and the limb stiffness improvement are successful, and the reduced deformation is very close to the estimated value as well.

关键词： Ladder climbing Legged robot Bionic robot Gait.Stiffness improvement Finite element analysis

Comparison of generalized engine control and MPC based on maximum principle

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Control Theory and Technology 2017年第2期15卷 150-157页

作者： akira OHATA TECHNOVA Inc. The Imperial Hotel Tower 1-1 Uchisaiwai-cho 1 Chiyoda-ku Tokyo 100-0011 Japan

Automotive engine control has been continuously improved due to the strong demands from the society and the market since introducing electronic controls but not always following control theories. Therefore, it is not easy for researchers from academia and even engineers from the automotive industry to grasp the whole aspect of engine control. To encounter the issue, important features of engine control are extracted and generalized from the standpoint of control engineering. Comparisons of the control and model predictive control （MPC） showed an outstanding performance of the control generalized from engine controls and how to apply MPC in the framework.

关键词： Automotive engine history of engine control control design input constraints time delay model predictive control

Application of multi-dimensional wavelet transform to fluid mechanics

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Theoretical & Applied Mechanics Letters 2020年第2期10卷 98-115页

作者： akira Rinoshika Hiroka Rinoshika School of Aeronautic Science and Engineering Beihang UniversityBeijing100191China Department of Mechanical Systems Engineering Graduate School of Science and Engineering Yamagata University 4-3-16 JonanYonezawa-shiYamagata 992-8510Japan

This paper first reviews the application research works of wavelet transform on the fluid mechanics. Then the theories of continuous wavelet transform and multi-dimensional orthogonal(discrete) wavelet transform, including wavelet multiresolution analysis, are introduced. At last the applications of wavelet transform on 2 D and 3 D turbulent wakes and turbulent boundary layer flows are described based on the hot-wire, 2 D particle image velocimetry(PIV) and 3 D tomographic PIV.

关键词： Continuous wavelet transform Fluid mechanics Multi-scale flow structures Orthogonal wavelet transform Turbulence Wavelet multiresolution analysis

An Improvement of Multigrid Methods Using Multiple Grids on Each Layer for Parallel Computing

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Journal of Mathematical Research with Applications 2021年第1期41卷 87-98页

作者： akira IMAKURA University of Tsukuba

Multigrid methods are widely used and well studied for linear solvers and preconditioners of Krylov subspace methods. The multigrid method is one of the most powerful approaches for solving large scale linear systems; however, it may show low parallel efficiency on coarse grids. There are several kinds of research on this issue. In this paper, we intend to overcome this difficulty by proposing a novel multigrid algorithm that has multiple grids on each layer.Numerical results indicate that the proposed method shows a better convergence rate compared with the existing multigrid method.

关键词： linear systems multigrid preconditioner

Effect of Intertidal Elevation at Tsuyazaki Cove,Fukuoka,Japan on Survival Rate of Horseshoe Crab Tachypleus tridentatus Eggs

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Journal of Ocean University of China 2022年第3期21卷 601-610页

作者： ITAYA Shinji SHUUNO Mari ONIKURA Norio TAI akira YANO Shinichiro Environmental Fluid Dynamics Laboratory Department of Urban and Environmental EngineeringGraduate School of EngineeringKyushu UniversityFukuoka819-0395Japan Tsuyazaki Seaside Nature School Fukutsu811-3304Japan Fishery Research Laboratory Department of Bioresource ScienceGraduate School of Bioenvironmental ScienceKyushu UniversityFukuoka819-0395Japan

Physical factors affecting the survival of Tachypleus tridentatus eggs were investigated by translocating their eggs between the high intertidal zone and the low intertidal zone of a known spawning site.The mean egg survival rates per day were highest in the mid intertidal zone(45.1%±25.4%)and the lowest in the low intertidal zone(13.3%±27.6%).Differences in the elevation,air exposure time,and water content of the spawning ground were significant factors determining the egg survival rates.Excessive or insufficient air exposure time resulted in inadequate water content at higher and lower intertidal zones and could reduce egg survival.On the other hand,moderate saturation and dehydration were repeated with each tidal movement in the mid intertidal zone.This dynamic is considered as one of the crucial factors for the survival of eggs and is considered optimal for spawning.Therefore,the protection of the mid intertidal zone is imperative for maximizing the egg survival rate in Tsuyazaki Cove where almost all suitable nesting sites have disappeared due to coastal development.By protecting these optimal sites for spawning and recovering other optimal sites on suitable beaches,a positive contribution can be made to future management and conservation.The study also suggests that translocating eggs from marginal to optimal spawning sites might be a recovery strategy for this globally endangered species.

关键词： air exposure time globally endangered species intertidal elevation intertidal zone optimal spawning site Tachypleus tridentatus translocated horseshoe crab eggs Tsuyazaki Cove

Growth phase dependent changes in the structure and protein composition of nucleoid in Escherichia coli

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Science China(Life Sciences) 2015年第9期58卷 902-911页

作者： TALUKDER AliAzam ISHIHAMA akira Department of Microbiology Jahangirnagar University Micro-Nano Technology Research Center Hosei University Department of Molecular Genetics National Institute of Genetics

The genomic DNA of bacteria is highly compacted in a single or a few bodies known as nucleoids. Here, we have isolated Escherichia coli nucleoid by sucrose density gradient centrifugation. The sedimentation rates, structures as well as protein/DNA composition of isolated nucleoids were then compared under various growth phases. The nucleoid structures were found to undergo changes during the cell growth; i. e., the nucleoid structure in the stationary phase was more tightly compacted than that in the exponential phase. In addition to factor for inversion stimulation(Fis), histone-like nucleoid structuring protein(H-NS), heat-unstable nucleoid protein(HU) and integration host factor(IHF) here we have identified, three new candidates of E. coli nucleoid, namely DNA-binding protein from starved cells(Dps), host factor for phage Qβ(Hfq) and suppressor of td- phenotype A(Stp A). Our results reveal that the major components of exponential phase nucleoid are Fis, HU, H-NS, Stp A and Hfq, while Dps occupies more than half of the stationary phase nucleoid. It has been known for a while that Dps is the main nucleoid-associated protein at stationary phase. From these results and the prevailing information, we propose a model for growth phase dependent changes in the structure and protein composition of nucleoid in E. coli.

关键词：蛋白组成生长阶段核结构菌类大肠依赖性蔗糖密度梯度离心法基因组DNA