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Naoyuki Hashimoto

Bio: Naoyuki Hashimoto is an academic researcher from Hokkaido University. The author has contributed to research in topics: Hardening (metallurgy) & Irradiation. The author has an hindex of 30, co-authored 172 publications receiving 3587 citations. Previous affiliations of Naoyuki Hashimoto include Hiroshima University & Oak Ridge National Laboratory.


Papers
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Journal ArticleDOI
TL;DR: In this paper, the authors investigated the temperature dependencies of true strain-hardening and plastic-instability properties for austenitic stainless steels; including annealed 304, 316, 316LN, and 20% cold-worked 316LNs, at test temperatures from −150 to 450 °C.

350 citations

Journal ArticleDOI
TL;DR: The tensile and creep properties of two oxide dispersion-strengthened (ODS) steels with nominal compositions of Fe-12Cr-0.4Ti-O3 (12YWT) and Fe-14Cr-2.5W−0.25Y2O3 were investigated in this article.

214 citations

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TL;DR: In this article, the authors examined the hydrogen embrittlement of a commercial grade pure iron by using repeated stress-relaxation tests under simultaneous cathodic hydrogen charging and found that hydrogen accelerates the evolution of the dislocation microstructure through the hydrogen-enhanced plasticity mechanism.

187 citations

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TL;DR: In this article, the development of chemically vapor-deposited (CVD) high-purity beta-SiC during neutron and self-ion irradiation at elevated temperatures was studied.

156 citations

Journal ArticleDOI
TL;DR: In this article, a set of ODS steels with varying oxide particle dispersion were irradiated at 650°C, using 3.2 MeV Fe + and 330 keV He + ions simultaneously.

139 citations


Cited by
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01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Journal Article
TL;DR: In this paper, the authors presented a method to detect the presence of a tumor in the human brain using EPFL-206025 data set, which was created on 2015-03-03, modified on 2017-05-12
Abstract: Note: Times Cited: 875 Reference EPFL-ARTICLE-206025doi:10.1021/cr0501846View record in Web of Science URL: ://WOS:000249839900009 Record created on 2015-03-03, modified on 2017-05-12

1,704 citations

Journal ArticleDOI
TL;DR: In this article, the three major materials challenges for the current and next generation of water-cooled fission reactors are centered on two structural materials aging degradation issues (corrosion and stress corrosion cracking of structural materials and neutron-induced embrittlement of reactor pressure vessels), along with improved fuel system reliability and accident tolerance issues.

1,633 citations

Journal ArticleDOI
TL;DR: The potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications is demonstrated, with austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibiting a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels.
Abstract: Many traditional approaches for strengthening steels typically come at the expense of useful ductility, a dilemma known as strength-ductility trade-off. New metallurgical processing might offer the possibility of overcoming this. Here we report that austenitic 316L stainless steels additively manufactured via a laser powder-bed-fusion technique exhibit a combination of yield strength and tensile ductility that surpasses that of conventional 316L steels. High strength is attributed to solidification-enabled cellular structures, low-angle grain boundaries, and dislocations formed during manufacturing, while high uniform elongation correlates to a steady and progressive work-hardening mechanism regulated by a hierarchically heterogeneous microstructure, with length scales spanning nearly six orders of magnitude. In addition, solute segregation along cellular walls and low-angle grain boundaries can enhance dislocation pinning and promote twinning. This work demonstrates the potential of additive manufacturing to create alloys with unique microstructures and high performance for structural applications.

1,385 citations

Journal ArticleDOI
TL;DR: In this paper, a compilation of non-irradiated and irradiated properties of SiC are provided and reviewed and analyzed in terms of application to TRISO fuels, specifically in the high-temperature irradiation regime.

1,106 citations