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Erosion and Modifications of Tungsten-Coated Carbon and Copper Under High Heat Flux

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Plasma Science and Technology 2003年第4期5卷 1887-1894页

作者：刘翔 S.Tamura k.tokunaga N.Yoshida 张斧许增裕葛昌纯 N.Noda Southwestern Institute of Physics Chengdu 610041China Research Institute for Applied Mechanics Kyushu University6-1 Kasuga-parkKasugaFukuoka 816-8580Japan Laboratory of Special Ceramics and Powder Metallurgy University of Science and Technology BeijingBeijing 100083China National Institute for Fusion Science TokiGifu 509-5292Japan

Tungsten-coated carbon and copper was prepared by vacuum plasma spraying (VPS) and inert gas plasma spraying (IPS), respectively. W/CFC (Tungsten /Carbon Fiber-Enhanced material) coating has a diffusion barrier that consists of W and Re multi-layers pre-deposited by physical vapor deposition on carbon fiber-enhanced materials, while W/Cu coating has a graded transition interface. Different grain growth processes of tungsten coatings under stable and transient heat loads were observed, their experimental results indicated that the recrystallizing temperature of VPS-W coating was about 1400 ℃ and a recrystallized columnar layer of about 30 μm thickness was formed by cyclic heat loads of 4 ms pulse duration. Erosion and modifications of W/CFC and W/Cu coatings under high heat load, such as microstructure changes of interface, surface plastic deformations and cracks, were investigated, and the erosion mechanism (erosion products) of these two kinds of tungsten coatings under high heat flux was also studied.

关键词： plasma spraying tungsten coatings recrystallization plastic deformation erosion products

Mechanism of Surface Modification and Internal Damage in Plasma Facing Materials under Helium Plasma Bombardment

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Mechanism of Surface Modification and Internal Damage in Pla...

Studies on multiferroic materials in high magnetic fields

Ninth China-Japan Symposium on Materials for Advanced Energy Systems and Fission & Fusion Engineering Jointed with CAS-JSPS Core-university Program Seminar on Fusion Materials, System and Design Integration

作者： N.Yoshida H.Iwakiri k.tokunaga N.Ohno S.Takamura Research Institute for Applied Mechanics kyushu University kasuga Japan Research Institute for Applied Mechanics kyushu University kasuga Japan Research Institute for Applied Mechanics kyushu University kasuga Japan Eco TopiaScience Institute Nagoya University Nagoya Japan Graduate School of Engineering Nagoya University Nagoya Japan

Plasma facing materials of fusion devices suffer serious irradiation of hydrogen isotopes and helium with energy up to a few *** case of metallic materials,irradiation effects of helium are especially important,because helium atoms enhance the accumulation of damage due to very strong interaction with radiation induced lattice *** and its alloy are expected as potential candidates for a plasma facing *** to the recent extensive works, irradiation of fusion relevant low energy helium results in serious degradation of material properties as a plasma facing component.

关键词： Mechanism of Surface Modification and Internal Damage in Plasma Facing Materials under Helium Plasma Bombardment

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Frontiers of physics 2012年第4期7卷 386-398页

作者： Masashi tokunaga The International MegaGauss Science Laboratory The Institute for Solid State Physics (IMGSL-ISSP) The University of Tokyo Kashiwa 277-8581 Japan

In this article, studies on the magnetoelectric effects of multiferroic materials in high magnetic fields, particularly pulsed magnetic fields, are discussed and results for some representative ma- terials are presented. In the discussions on representative materials, the relationship between the crystallographic symmetry and the linear magnetoelectric effect in Cr203 is introduced. Then dras- tic changes in polarization caused by magnetic transitions are discussed through a case study of manganites with a perovskite4ype structure. In addition, high field studies on the magnetoelectric effects in BiFeO3, which is an exceptional multiferroic material, are presented and discussed in the framework of the Landau-Ginzburg theory.

关键词： high magnetic field multiferroic materials magnetoelectric effect

Coatings on Mg alloys and their mechanical properties: A review

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Journal of Materials Science & Technology 2018年第7期34卷 1119-1126页

作者： Toko tokunaga Munekazu Ohno kiyotaka Matsuura Faculty of Engineering Hokkaido University

Poor corrosion resistance is a serious drawback of Mg alloys, restricting their practical applications. Coating is one of the effective techniques for improvement in the poor corrosion resistance. In this paper, the coating processes for Mg alloys so far developed are reviewed. Among several processes, the coating processes based on mechanical energy, including metal forming, are attractive because the corrosion resistance and formability of Mg alloys are simultaneously improved.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

关键词： Magnesium alloy Coating Mechanical property Corrosion resistance

Gastric adenocarcinoma of fundic gland type with signet-ring cell carcinoma component: A case report and review of the literature

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World Journal of Gastroenterology 2018年第26期24卷 2915-2920页

作者： keita kai Masaaki Satake Osamu tokunaga Department of Pathology Saga University Hospital Department of Gastroenterology Koga Hospital 21 Department of Pathology Shin Koga Hospital

A depressed lesion was found at a gastric angle of 76-yearold Japanese woman by esophagogastroduodenoscopy. Four years prior, she was diagnosed with a Helicobacter pylori infection but no eradication was performed. The pathological diagnosis of biopsy specimens was signet-ring cell carcinoma. Endoscopic submucosal dissection(ESD) was performed. Histopathological examination of the ESD specimen revealed proliferation of well-differentiated tubular adenocarcinoma mimicking fundic gland cells at the deep layer of the lamina propria mucosae. These tumor cells expressed focally pepsinogen-Ⅰ, diffusely MUC6, and scattered H^+/k^+ ATPase according to immunohistochemistry. Therefore, we diagnosed this tumor as gastric adenocarcinoma of fundic gland type(GA-FG). Adjacent to the GA-FG, proliferation of signet-ring cell carcinoma which diffusely expressed MUC 2 and MUC 5AC was observed. Intestinal metaplasia was focally observed in the surrounding mucosa of the signet-ring cell carcinoma. To the best of our knowledge, this is the first case report of GA-FG with a signet-ring cell carcinoma component. The origin of signet-ring cell carcinoma, i.e., whether it accidentally arose from a non-neoplastic mucosa and coexisted with the GA-FG or dedifferentiated from the GA-FG is unclear at present. We expect the accumulation of similar cases and further analysis to clarify this issue.

关键词： Gastric adenocarcinoma of fundic gland type Endoscopic submucosal dissection Helicobacter pylori Intestinal metaplasia Signet-ring cell carcinoma

Ultrahigh Resolution Fiber-Optic Quasi-Static Strain Sensors for Geophysical Research

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Photonic Sensors 2013年第4期3卷 295-303页

作者： Zuyuan HE Qingwen LIU Tomochika tokunaga State key Lab of Advanced Optical Communication Systems and Networks Shanghai Jiao Tong University Shanghai200240 China Department of Environment Systems University of Tokyo Chiba 277-8563 Japan

A review of our recent work on ultrahigh resolution optical fiber sensors in the quasi-static region is presented, and their applications in crustal deformation measurement are introduced. Geophysical research such as studies on earthquake and volcano requires monitoring the earth＇s crustal deformation continuously with a strain resolution on the order of nano-strains （ne） in static to low frequency region. Optical fiber sensors are very attractive due to their unique advantages such as low cost, small size, and easy deployment. However, the resolution of conventional optical fiber strain sensors is far from satisfactory in the quasi-static domain. In this paper, several types of recently developed fiber-optic sensors with ultrahigh resolution in the quasi-static domain are introduced, including a fiber Bragg grating （FBG） sensor interrogated with a narrow linewidth tunable laser, an FBG based fiber Fabry-Perot interferometer （FFPI） sensor by using a phase modulation technique, and an FFPI sensor with a sideband interrogation technique. Quantificational analyses and field experimental results demonstrated that the FBG sensor can provide nano-order strain resolution. The sub-nano strain resolution was also achieved by the FFPI sensors in laboratory. Above achievements provide the basis to develop powerful fiber-optic tools for geophysical research on crustal deformation monitoring.

关键词： Ultrahigh resolution fiber Bragg grating frequency modulation crustal deformation measurement

Activation of Trifluoromethylthio Moiety by Appending Iodonium Ylide under Copper Catalysis for Electrophilic Trifluoromethylation Reaction

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Chinese Journal of Chemistry 2016年第5期34卷 485-489页

作者： Ibrayim Saidalimu Shugo Suzuki Etsuko tokunaga Norio Shibata Department of Frontier Materials Nagoya Institute of Technology Gokiso Showa-ku Nagoya 466-8555 Japan Department of Nanopharmaceutical Sciences Nagoya Institute oF Technology Gokiso Showa-ku Nagoya 466-8555 Japan

A novel iodonium-ylide compound 2 that appends a trifluoromethylthio （SCF3） group is disclosed as a new, shelf-stable electrophilic trifluoromethylation reagent. Unlike known shelf-stable electrophilic trifluoromethylation reagents, 2 has a stable SCF3 group which is activated by appending iodonium ylide under copper catalysis via sul- fonium ylide to generate a cationic trifluoromethyl （CF3） species. Reagent 2 was found to be an efficient electro- philic trifluoromethylation reagent for a wide range of silyl enol ethers 3 under copper catalysis. Cyclic and acyclic a-trifiuoromethyl ketones 4 were obtained by reagent 2 in moderate to good yields. On the other hand, a difluoro- methylthio analogue 5 did not affect intermolecular transfer difluoromethylation to substrates. Instead, intramolecu- lar 1,4-migration proceeded similar to the Stevens rearrangement to provide 6 in 21% yield, independent of the presence of nucleophiles 3.

关键词： trifluoromethylation difluoromethylation iodine sulfur ylide

Fabrication of Al-Coated Mg-Li Alloy Sheet and Investigation of Its Properties

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Acta Metallurgica Sinica(English Letters) 2019年第2期32卷 169-177页

作者： Tian-Long Zhang Toko tokunaga Munekazu Ohno Mi-Lin Zhang kiyotaka Matsuura Graduate School of Engineering Hokkaido University Faculty of Engineering Hokkaido University College of Materials Science and Chemical Engineering Harbin Engineering University

An Al-coated Mg-8 mass% Li alloy rectangular bar was fabricated by hot extrusion, and then, it was hot-rolled into a thin sheet. The Al coating was uniform in thickness and had good bonding with the substrate during all the processing. This Alcoated Mg–Li alloy exhibited a good corrosion resistance in a 0.5 mass% HCl aqueous solution. No intermetallic compound was observed at the Al/Mg–Li interface after the extrusion and the rolling. The Al-coated Mg–Li alloy sheet exhibited an elongation to fracture of 35% at room temperature at a strain rate of 0.001 s(-1)without any debonding between the coating and the substrate. When tensile tested at 573 k at 0.001 s(-1)in the air, the Al coating remained undamaged even until an elongation of about 150%. Further elongation generated cracks on the coating and the specimen fractured at an elongation of about 200%. In an Ar atmosphere, the specimen exhibited a fracture elongation of over 400% under the same conditions at 573 k at 0.001 s(-1), although a large number of cracks generated on the Al coating.

关键词： Mg–Li alloy Composite material Coating Mechanical properties Superplasticity

Genome-Wide Association Study Reveals Host Genetic Factors for Liver Diseases

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Journal of Clinical and Translational Hepatology 2013年第1期1卷 45-50页

作者： Nao Nishida katsushi tokunaga Masashi Mizokami The Research Center for Hepatitis&Immunology National Center for Global Health and Medicine Ichikawa Chiba Japan Department of Human Genetics The University of Tokyo Bunkyo-ku Tokyo Japan Department of Human Genetics The University of Tokyo Bunkyo-ku Tokyo Japan The Research Center for Hepatitis&Immunology National Center for Global Health and Medicine Ichikawa Chiba Japan

A number of disease-associated genetic markers for common liver diseases have been identified using genome-wide association studies (GWASs). The GWAS strategy is based on genome-wide single-nucleotide polymorphism typing technologies, which are now commercially available, accom-panied by statistical methods to identify host genetic factors that are associated with target diseases or complex genetic traits. One of the most striking features of the GWAS strategy is the ability to identify unexpected disease-associated genetic markers across the entire human genome. Here, we describe the technological aspects of the GWAS strategy with examples from actual GWAS reports related to hepatitis research, including drug response for patients with chronic hepatitis C, susceptibility to primary biliary cirrhosis, and hepatitis-B-related hepatocellular carcinoma.

关键词： GWAS Hepatitis B infection Hepatitis C infection Primary biliary cirrhosis HLA-DP Hepatocellular carcinoma Host genetic factors