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Photonics Research 2023年第2期11卷 181-188页

作者： KUNHAO JI DI LIN IAN A. DAVIDSON SIYI WANG JOEL CARPENTER yoshimichi amma YONGMIN JUNG MASSIMILIANO GUASONI DAVID J. RICHARDSON Optoelectronics Research Centre University of SouthamptonSouthampton SO171BJUK Institute of Advanced Photonics Technology School of Information EngineeringGuangdong University of TechnologyGuangzhou 510006China Guangdong Provincial Key Laboratory of Photonics Information Technology Guangdong University of TechnologyGuangzhou 510006China School of Information Technology and Electrical Engineering The University of QueenslandBrisbaneQLD 4072Australia Fujikura Ltd. Chiba 285-8550Japan

Higher-order Poincarésphere(HOPS) beams with spatially variable polarization and phase distributions are opening up a host of unique applications in areas ranging from optical communication to ***, the flexible generation of these beams with high peak power from compact laser systems remains a challenge. Here, we demonstrate the controlled generation of HOPS beams based on coherent beam combination from an Yb-doped multicore fiber(MCF) amplifier. Using a spatial light modulator to adaptively adjust the wavefront and polarization of the signals seeded into the individual cores of the MCF various structured beams(including cylindrical vector beams and first-and second-order vortex beams) were generated with peak powers up to 14 k W for ~92 ps pulses.

关键词： amplifier polarization fiber

Thermal ageing of soft and hard epoxy resins

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High Voltage 2023年第1期8卷 12-20页

作者： yoshimichi Ohki Naoshi Hirai Research Institute for Materials Science and Technology Waseda UniversityShinjuku-kuTokyoJapan

Two kinds of epoxy resin,a soft one with rubber-based additives and an ordinary hard one,are used as electrical insulators and airtight sealants in electrical penetrations in nuclear power plants(NPPs).Knowing how they behave under adverse environments is important for the safe operation of *** this regard,we gave artificial thermal ageing treatment to the two resins by heating them in air at various *** resins were then subjected to mechanical,thermal,and dielectric *** a result,it has become clear that the soft epoxy resin becomes hard,while its permittivity and loss factor decrease as the heating becomes *** glass transition tends to occur at a high temperature in the soft epoxy resin when it was *** these changes,the soft resin tends to exhibit similar behaviour in various properties to that of the unaged hard *** the other hand,the hard one is hardly affected by the simulated thermal ***,both resins can be useable in NPPs.

关键词： resin resins heated

Broadband FIR absorption spectra of lowdensity polyethylene sheets containing six different antioxidants and estimation of their contents by chemometric analysis

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High Voltage 2019年第3期4卷 161-166页

作者： Takaaki Ogishima Chiaki Kuroda Naoshi Hirai yoshimichi Ohki Department of Electrical Engineering and Bioscience Waseda UniversityShinjuku-kuTokyo 169-8555Japan Research Institute for Materials Science and Technology Waseda UniversityShinjuku-kuTokyo 169-8555Japan Cooperative Major in Nuclear Energy Waseda UniversityShinjuku-kuTokyo169-8555Japan

Antioxidants are usually added to polymeric insulating materials to suppress oxidative ***,the details of antioxidant added to a polymer are often not *** the other hand,compared to mid-infrared absorption spectroscopy,terahertz(THz)absorption spectroscopy,and far-infrared(FIR)absorption spectroscopy have not been performed so *** on the above backgrounds,six different kinds of antioxidants were added into low-density polyethylene sheets with four different contents,and their THz and FIR absorption spectra were *** a result,it has become clear that each antioxidant shows its specific absorption peaks,by which the antioxidants can be ***,the antioxidant content can be estimated by the absorption intensity of the specific peak.A chemometric analysis can make the estimation more accurately than a simple comparison of absorption intensity.

关键词： FIR absorption estimation

Surface flashover in 50 years:Theoretical models and competing mechanisms

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High Voltage 2023年第5期8卷 853-877页

作者： Zhen Li Ji Liu yoshimichi Ohki George Chen He Gao Shengtao Li Key Laboratory of Engineering Dielectrics and Its Application Ministry of EducationHarbin University of Science and TechnologyHarbinChina State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina Research Institute for Materials Science and Technology Waseda UniversityShinjuku‐kuJapan School of Electronics and Computer Science University of SouthamptonSouthamptonUK

Surface flashover is a devastating electronic avalanche along the gas–solid interface when a high electric field is applied,which is a potential issue that threatens the safe operations of advanced power electronic,electrical,and spacecraft ***,the underlying physical mechanisms for surface flashover development are still under investigation owing to the complex charge transport processes through the gas phase,solid phase,and gas–solid *** this study,the history of surface flashover theory in the last 50 years is introduced,and several key questions are reviewed from the perspective of the competing mechanisms of charge transport:the role of each phase in a surface flashover,the origin of surface charging,and effects of traps in solid on surface ***,some suggestions involve charge transport processes in each phase,and their correlations are put forward,and a predictable‘charge transport competitive flashover model’is proposed by clarifying the competing mechanisms of charge transport processes through multiple *** study summarises the history and hot topics of physical mechanisms of surface flashover proposed based on classic and recent progress and offers promising routes for developing a more precise surface flashover theory and improving surface flashover performances.

关键词： flash transport charge

Experimental investigation of the degradation mechanism of silicone rubber exposed to heat and gamma rays

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High Voltage 2017年第2期2卷 92-101页

作者： Shugo Hanada Maki Miyamoto Naoshi Hirai Liuqing Yang yoshimichi Ohki Department of Electrical Engineering and Bioscience Waseda University3-4-1 OhkuboShinjuku-kuTokyoJapan Research Institute for Materials Science and Technology Waseda University2-8-26 Nishi-WasedaShinjuku-kuTokyoJapan State Key Laboratory for Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anPeople's Republic of China Cooperative Major in Nuclear Energy Waseda University3-4-1 OhkuboShinjuku-kuTokyoJapan

Cable-grade silicone rubber was aged thermally or by combining heat and gamma-ray radiation,and resultant changes in chemical,thermal,mechanical and electrical properties were *** experimental results obtained in these analyses are clearly consistent with the mechanism that silicone rubber is degraded by forming cross-linked structures via formation of abundant siloxane *** further progress of degradation,decomposition becomes *** these mechanisms,mechanical properties deteriorate dramatically by losing *** the real and imaginary parts of complex permittivity decrease,which is a contrastive difference from typical ageing behaviour of organic insulating *** addition,both the elongation at break and indenter modulus are good indicators of degradation of silicone rubber.

关键词： rubber mechanism modulus

Triterpenoid inducers of Nrf2 signaling as potential therapeutic agents in sickle cell disease： a review

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Frontiers of Medicine 2015年第1期9卷 46-56页

作者： amma Owusu-Ansah Sung Hee Choi Agne Petrosiute John J. Letterio Alex Yee-Chen Huang Division of Pediatric Hematology-Oncology Department of Pediatrics Case Western Reserve University School of Medicine Cleveland OH 44106 USA The Angie Fowler Adolescent & Young Adult Cancer Institute at University Hospitals Rainbow Babies & Children 's Hospital Cleveland OH 44106 USA

Sickle cell disease （SCD） is an inherited disorder of hemoglobin in which the abnormal hemoglobin S polymerizes when deoxygenated. This polymerization of hemoglobin S not only results in hemolysis and vaso- occlusion but also precipitates inflammation, oxidative stress and chronic organ dysfunction. Oxidative stress is increasingly recognized as an important intermediate in these pathophysiological processes and is therefore an important target for therapeutic intervention. The transcription factor nuclear erythroid derived- 2 related factor 2 （Nrf2） controls the expression of anti-oxidant enzymes and is emerging as a protein whose function can be exploited with therapeutic intent. This review article is focused on triterpenoids that activate Nrf2, and their potential for reducing oxidative stress in SCD as an approach to prevent organ dysfunction associated with this disease. A brief overview of oxidative stress in the clinical context of SCD is accompanied by a discussion of several pathophysiological mechanisms contributing to oxidative stress. Finally, these mechanisms are then related to current management strategies in SCD that are either utilized currently or under evaluation. The article concludes with a perspective on the potential of the various therapeutic interventions to reduce oxidative stress and morbidity associated with SCD.

关键词： oxidative stress Nrf2 triterpenoids sickle cell disease vaso-occlusion CDDO-Me

Spatial Heterogeneity and Variability of a Large-Scale Vegetation Community Using a Power-Law Model

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Tsinghua Science and Technology 2005年第4期10卷 469-477页

作者：宋志远黄大明 SHIYOMI Masae 王昱生 TAKAHASHI Shigeo yoshimichi Hori YAMAMURU Yasuo 陈俊 Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China Faculty of Science Ibaraki University Bunkyo 2-1-1 Mito 310-8512 Japan College of Animal Science Northeast Agricultural University Harbin 150030 China National Institute of Livestock and Grassland Science 768 Senbonmatsu Nishinasuno Tochigi 329-2793 Japan

Spatial heterogeneity and stability are fundamental indices for describing vegetation communities. The spatial distribution characteristics of the vegetation in Nenjiang region of northeastern China were evaluated using a variance power-law model. The data fits the model well with estimates given for the levels of heterogeneity for not only single species but also the community as a whole. The linear regression indicates that the species in the community exhibit a consistently organized spatial pattern, as is often discovered in field surveys but rarely seen in artificial systems. The species deviations from the regression line, which exhibit a leptokurtic distribution, may reflect the variability of the community. Thus, the model provides a general tool for management and regulation of ecosystems, especially where there is human disturbances.

关键词： power-law model spatial heterogeneity community variability leptokurtic distribution resilience

Fractals in Spatial Patterns of Vegetation Formations

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Tsinghua Science and Technology 2006年第4期11卷 462-469页

作者：宋志远黄大明 Masae Shiyomi 王昱生 Shigeo Takahashi Hori yoshimichi Yasuo Yamamuru 陈俊 Institute of Ecology Department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China Faculty of Science Ibaraki University Bunkyo 2-1-1 Mito 310-8512 Japan Grassland Research Station College of Animal Science Northeast Agricultural University Harbin 150030 China National Institute of Livestock and Grassland Science 768 Senbonmatsu Nishinasuno Tochigi 329-2793 Japan

The spatial distribution patterns of species are always scale-dependent and spatially self-similar in ecological systems. In this work, vegetation distribution data collected from the vegetation map of the Xigaze region was analyzed using a box-counting method. The power law of the box-counting dimension （DB） across a range of scales （5-160 km） confirms the fractal patterns for most vegetation formations, while the fluctuations of the scale-specific DB among the different abundance groups indicate limitations of fractal coherence. The fractal method is shown to be a useful tool for measuring the distribution patterns of vegetation formations across scales, which provides important information for both species and habitat conservation, especially in landscape management.

关键词： area of occupancy box-counting dimension fractal scale vegetation formation

Orexin-a regulates body temperature in coordination with control of arousal state

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中国病理生理杂志 2001年第8期 77-78页

作者： G.yoshimichi H.Yoshimatsu T.Masaki T.Sakata Department of Internal Medicine I School of Medicine Oita Medical University Oita Japan

Spatial Heterogeneity of Vegetation in China

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Tsinghua Science and Technology 2007年第4期12卷 424-434页

作者：黄大明王昱生 Masae Shiyomi 柳小妮宋百敏陈俊 Shigeo Takahashi yoshimichi Hori Yasuo Yamamura Ecology Research Station Department of Biological Sciences and Biotechnology Tsinghua University Grassland Research Station College of Animal Science and Technology Northeast Agricultural University Faculty of Science Ibaraki University Bunkyo 2-1-1 Mito 310-8512 Japan National Institute of Livestock and Grassland Science 768 Senbonmatsu Nishinasuno Tochigi 329-2793 Japan

The spatial heterogeneity and ecological characteristics of 74 vegetation types and the lack of vegetation type within the 9.6 million km2 of Chinese territory were studied using data from the China vegetation map. The analysis used 877 large quadrats 10 mm×10 mm （actual size 100 km×100 km）, which covered about 8.77 million km^2. Each large-quadrat was divided into four small 5 mm×5mm quadrats （actual size 50 km×50 km）. The frequency of occurrence of all vegetation types was recorded in each small quadrat. The survey using the Shiyomi method of vegetation analysis based on the beta-binomial distribution was adopted to describe the frequency of occurrence and spatial heterogeneity for each kind of vegetation. The weighted average heterogeneity of all the vegetation types in the landscape provides a measure of the landscape level heterogeneity which describes the spatial intricacy of the existing vegetation composition. The maximum spatial vegetation heterogeneity was 0.8620 in the frigid-temperate coniferous forest of Larix （V1）, which dominates cold moist northeast China. The minimum spatial heterogeneity with a low occurrence was the Caragana tibetica in the gravel desert in the western Yellow River Hetao area. The minimum occurrence with a low spatial heterogeneity was the Monsoon rainforest on rock in Guangxi and Yunnan Provinces. The vegetation types on the Qing-Zang Plateau were found to be representative of Chinese vegetation because of the very high occurrence and spatial heterogeneity of these vegetation types. The weighted average of the heterogeneity was 0.677, while the vegetation diversity index was 3.29.

关键词： spatial heterogeneity beta-binomial distribution ecosystem evaluation Chinese vegetation