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World Journal of Mechanics 2017年第8期7卷 195-210页

作者： Yohei Sakakibara keiji kubushiro IHI Corporation Research Laboratory: 1 Shin-Nakahara cho Isogo ku Yokohama shi Japan

This paper studies a method for obtaining the stress with plastic deformation by finding the plastic strain on U-bent specimens of austenitic stainless steel that have been subjected to large plastic deformation using the EBSD (Electron Backscatter Diffraction) method. The Mises stress calculated on the basis of the KAM of the EBSD shows good agreement with the stress that can be geometrically calculated from the U-bent specimens. In contrast, general methods for measuring residual stress on the basis of elastic strain produce residual stress measurement results that differ specimen by specimen. Thus, for true strain not less than 0.05, stress estimation based on the EBSD method produces better results than other general methods.

关键词： Stainless Steel EBSD Plastic Strain Misorientation

The Effect of Cold Working on Creep Rupture Strength and Microstructure of Ni-23Cr-7W Alloy

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World Journal of Mechanics 2017年第10期7卷 283-295页

作者： Yoshiki Shioda keiji kubushiro Youhei Sakakibara Kyohei Nomura Yoshinori Murata Research Laboratory IHI Corporation Yokohama Japan Department of Materials Physics and Energy Engineering Nagoya University Nagoya Japan

In order to clarify the reason why the creep rupture time of pre-strained Ni-23Cr-7W Alloy (HR6W) is longer than that of the non-pre-strained HR6W, microstructures of HR6W after a series of creep tests were investigated. The creep tests were conducted at 750°C, 90 and 100 MPa. In the pre-strained samples, the grain boundary shielding ratio by precipitates was larger than that of the non-pre-strained sample. In addition, in the pre-strained samples the size of the M23C6 carbide in the grains was finer than in the non-pre-strained sample. The W content in the M23C6 carbide in the pre-strained samples tended to be larger than in the non-pre-strained sample. Therefore, the Ostwald ripening of the carbide was delayed and the size of M23C6 carbide was thought to be fine for a long time. These observations show that creep strength in the pre-strained samples is higher than that of the non-pre-strained sample because of both precipitation strengthening inside of the grains and grain boundaries.

关键词： A-USC HR6W Cold Working Creep Strength Grain Boundary Shielding Ratio M23C6 Carbide

Bounded derived categories of very simple manifolds

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Science China Mathematics 2011年第8期54卷 1741-1750页

作者： OGUISO keiji Department of Mathematics Graduate School of ScienceOsaka University Korea Institute for Advanced Study

A non-representable cohomological functor of finite type of the bounded derived category of coherent sheaves of a compact complex manifold of dimension greater than one with no proper closed subvariety is given explic... 详细信息

关键词： derived category cohomological functor very simple manifold

A simple remark on a flat projective morphism with a Calabi-Yau fiber

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Science China Mathematics 2011年第8期54卷 1751-1756页

作者： OGUISO keiji Department of Mathematics Graduate School of ScienceOsaka University Korea Institute for Advanced Study

If a K3 surface is a fiber of a flat projective morphisms over a connected noetherian scheme over the complex number field,then any smooth connected fiber is also a K3 *** this,Professor Nam-Hoon Lee asked if the same is true for higher dimensional Calabi-Yau *** shall give an explicit negative answer to his question in each dimension greater than or equal to three as well as a proof of his initial observation.

关键词： flat projective morphism Hilbert scheme Calabi-Yau manifold

Circuit Implementation of Power Converter for High-Speed Switching Operations

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Chinese Journal of Electrical Engineering 2018年第3期4卷 47-52页

作者： keiji Wada Department of Electronics Engineering and Computer Science Tokyo Metropolitan UniversityTokyo Japan

Recently,high di/dt and dv/dt switching operations of power converter circuits has been discussed for realizing a high-efficiency power converter *** this case,parasitic inductances of the bus bar between a DC capacitor and power devices may cause issues of overshoot voltage and electromagnetic interference(EMI)***,it is necessary to design the bus bar geometry while considering the minimization and optimization of the parasitic inductance of bus *** paper discusses a relationship between bus bar geometry and switching *** addition,the bus bar analysis is based on the PEEC method,and the bus bar geometry is designed by considering the stray inductance with using an inductance-map ***,this paper also presents a design procedure of acceptable stray inductance based on a standardization *** should be noted that the stray inductance is designed not for minimization,but optimization,and it is shown not as an absolute value(H),but as a percentage value(%).Finally,the oscillation waveforms under turn-off operation will be discussed depending on the bus bar geometry.

关键词： Bus bar inductance bus bar geometry circuit implementation EMI switching characteristics

Is Goshinjo therapy effective in cognitive impairment after severe traumatic brain injury?

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Neural Regeneration Research 2013年第12期8卷 1146-1150页

作者： keiji Hashimoto Kisho Kida Hashimoto Cognitive Research Institute Tokyo 156-0051 Japan Kihodo Head Office Clinic Tokyo 151-0065 Japan

We report a case of a 21-year-old man who had severe traumatic brain injury as a result of an accident at the age of 16 years. Two years and 4 months after the trauma, at the age of 19 years, he still had severe right hemiplegia and cognitive dysfunction including aphasia and attention and memory disturbance. Conventional rehabilitation programs cou（d not resolve all of the neuropsychological problems. He started receiving Goshinjo therapy over a period of 22 months. Following the therapy, significant improvements in verbal intelligence quotient （assessed by the Wechsler Adult Intelligence Scale-Third Edition） and attention and concentration function （using the Wechsler Memory Scale-Revised）, and remission of traumatic epilepsy were observed. Goshinjo therapy is suspected to be effective in the treatment of cognitive dysfunction in the chronic stage after severe traumatic brain injury.

关键词： neural regeneration brain injury traumatic brain injury clinical practice Goshinjo therapy rehabilitation cognitive impairment energy field in human body Jaki neuroregeneration

Krein Parameters of Fiber-Commutative Coherent Configurations

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Algebra Colloquium 2020年第1期27卷 1-10页

作者： keiji Ito Akihiro Munemasa Research Center for Pure and Applied Mathematics Graduate School of Information SciencesTohoku UniversitySendaiJapan

For fiber-commutative coherent configurations,we show that Krein parameters can be defined essentially *** a consequence,the general Krein condition reduces to positive semidefiniteness of finitely many matrices determined by the parameters of a coherent *** mention its implications in the coherent configuration defined by a generalized *** also simplify the absolute bound using the matrices of Krein parameters.

关键词： coherent configuration association scheme Krein parameter Krein condition generalized quadrangle absolute bound

STUDY ON THE CHARACTERISTICS OF LONG TERM DISCHARGE OF A CATCHMENT

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Journal of Hydrodynamics 2000年第2期12卷 31-41页

作者： Hong, Lin Takase, keiji Sato, Koichi Wuhan Univ of Hydraulic and Electric Engineering Wuhan China

The characteristics of the catchment discharge vary with land use. The characteristics of the long-term discharge of a terraced paddy field catchment were studied. Two kind of tank models for land use were proposed and used to simulate the discharge of the catchment: one is a forest type model used as the upper part of the catchment; the other is a paddy field type model used as the lower part of the catchment. The results of the model simulation were analyzed and compared with that of a forest catchment.

关键词： Discharge (fluid mechanics) Land use Models Tanks (containers)

MICROSCOPIC HETEROGENEITY IN VISCOELASTIC PROPERTIES OF MOLECULAR ASSEMBLED SYSTEMS

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Chinese Journal of Polymer Science 2013年第1期31卷 1-1,2-11页

作者： Atsuomi Shundo David P. Penaloza keiji Tanaka Department of Applied Chemistry Kyushu University International Institute for Carbon-Neutral Energy Research (WPI-I2CNER) Kyushu University

An important step in understanding molecular assembled systems is to examine the structure and physical properties at various length scales and clarify the correlation between them. However, while the structures of these systems have been extensively studied from nanoscopic to macroscopic scales, their viscoelastic properties have been often limited to bulk rheological measurements. By using optical tweezers and particle tracking, we here show the local viscoelastic properties and their spatial distributions for the following systems： worm-like micelle solution, supramolecular hydrogel and lyotropic liquid crystal, which are formed by self-assembly of amphiphilic molecules in water. We found that all systems studied possessed a spatial heterogeneity in their viscoelastic properties and this was originated from the heterogeneous structures. It is interesting to note that there is the heterogeneity with the characteristic length scale of sub-micrometer or micrometer scale, thereby structures, although the systems are formed by molecules with nanometer size. The findings of these studies should lead to a better understanding of the dynamics of such systems.

关键词： Optical tweezers Soft materials Heterogeneity Hierarchical structure Rheological properties.

Effect of mechanical ball milling on the electrical and powder bed properties of gas-atomized Ti-48Al-2Cr-2Nb and elucidation of the smoke mechanism in the powder bed fusion electron b eam melting process

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Journal of Materials Science & Technology 2023年第6期137卷 36-55页

作者： Seungkyun Yim Kenta Aoyagi keiji Yanagihara Huakang Bian Akihiko Chiba Institute for Materials Research Tohoku University2-1-1 KatahiraSendaiMiyagi 980-8577Japan

Smoke is unexpected powder-splashing caused by electrostatic force and is one of the main problems hindering the process stability and applicability of the powder bed fusion electron beam(PBF-EB)*** this study,mechanical stimulation was suggested to suppress smoke of gas-atomized(GA)Ti-48Al-2Cr-2Nb powder using Al_(2)O_(3) and WC ball *** deformation mechanism of the GA powder depending on the ball milling media was discussed based on the developed particle morphology distribu-tion map and contact mechanics *** was revealed that the rapid decrement of flowability and packing density after WC ball milling owing to the formation of angular fragments by the brittle *** variation of surface and electrical properties by mechanical stimulation was investigated via XPS,TEM,and Impedance *** electrical resistivity of the ball-milled powders gradually decreased with increasing milling duration,despite the increased oxide film thickness,and the capacitive response disappeared in Al-60 and WC-30 via metal-insulator *** could be due to the accumulation of strain and defects on the oxide film via mechanical *** smoke mechanism of ball-milled powders was discussed based on the percolation *** the smoke experiment,smoke was more suppressed for WC-10 and WC-20 than that for Al-40 and Al-50,respectively,despite the longer charge dissipation *** could be due to the high probability of contact with conductive *** the Al-60 and WC-30 powders,smoke was further restricted by the formation of a percolation cluster with metal-like electrical *** believe that this study will contribute to a better understanding of the smoke mechanism and process optimization of the PBF-EB.

关键词： Metal-insulator transition Electron beam melting additive manufacturing Packing density Flowability Smoke mechanism Percolation theory