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Application of kelvin Probe to Studies of Fusion Reactor Materials under Irradiation

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Plasma Science and Technology 2005年第4期7卷 2982-2984页

作者：罗广南 k.yamaguchi T.Terai M.Yamawaki Department of Quantum Engineering and Systems Science Graduate School of Engineering The University of Tokyo7-3-1 KongoBunkyo-kuTokyo 113-8656Japan Neutron Science Rearch Center Japan Atomic Energy Research Institute 2-4 ShirakataTokai-muraIbaraki319-1195Japan

Recently, the work function （WF） changes in metallic and ceramic materials to be potentially used in future fusion reactors have been examined by means of kelvin probe （kP）, under He ion irradiation in high energy （MeV） and / or low energy （500 eV） ranges. The results of polycrystalline Ni samples indicate that the 1 MeV beam only induces decrease in the WF within the experimental fluence range; whereas the irradiation of 500 eV beam results in decrease in the WF firstly, then increase till saturation. A dual layer surface model is employed to explain the observed phenomena, together with computer simulation results by SRIM code. Charges buildup on the surface of lithium ceramics has been found to greatly influence the probe output, which can be explained qualitatively using a model concerning an induction electric field due to external field and free charges on the ceramic surface.

关键词： fusion reactor materials work function irradiation

Deuterium Retention and Physical Sputtering of Low Activation Ferritic Steel

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Plasma Science and Technology 2005年第2期7卷 2737-2740页

作者： T.Hino k.yamaguchi Y.Yamauchi Y.Hirohata k.Tsuzuki Y.kusama Department of Nuclear Engineering Hokkaido University Sapporo060-8628 JapanDepartment of Nuclear Engineering Hokkaido UniversitySapporo060-8628 JapanDepartment of Nuclear Engineering Hokkaido UniversitySapporo060-8628 JapanDepartment of Nuclear Engineering Hokkaido UniversitySapporo060-8628 JapanJapan Atomic Energy Research Institute NakaIbaraki-ken311-0193 JapanJapan Atomic Energy Research Institute NakaIbaraki-ken311-0193 Japan

Low activation materials have to be developed toward fusion demonstrationreactors. Ferritic steel, vanadium alloy and SiC/SiC composite are candidate materials of the firstwall, vacuum vessel and blanket components, respectively. Although changes of mechanical-thermalproperties owing to neutron irradiation have been investigated so far, there is little data for theplasma material interactions, such as fuel hydrogen retention and erosion. In the present study,deuterium retention and physical sputtering of low activation ferritic steel, F82H, wereinvestigated by using deuterium ion irradiation apparatus. After a ferritic steel sample wasirradiated by 1.7 keV D^+ ions, the weight loss was measured to obtain the physical sputteringyield. The sputtering yield was 0.04, comparable to that of stainless steel. In order to obtain theretained amount of deuterium, technique of thermal desorption spectroscopy (TDS) was employed to theirradiated sample. The retained deuterium desorbed at temperature ranging from 450 k to 700 k, inthe forms of DHO, D_2, D_2O and hydrocarbons. Hence, the deuterium retained can be reduced by bakingwith a relatively low temperature. The fluence dependence of retained amount of deuterium wasmeasured by changing the ion fluence. In the ferritic steel without mechanical polish, the retainedamount was large even when the fluence was low. In such a case, a large amount of deuterium wastrapped in the surface oxide layer containing O and C. When the fluence was large, the thickness ofsurface oxide layer was reduced by the ion sputtering, and then the retained amount in the oxidelayer decreased. In the case of a high fluence, the retained amount of deuterium became comparableto that of ferritic steel with mechanical polish or SS 316 L, and one order of magnitude smallerthan that of graphite. When the ferritic steel is used, it is required to remove the surface oxidelayer for reduction of fuel hydrogen retention. Ferritic steel sample was exposed to the envi

关键词： ferritic steel fuel hydrogen retention sputtering yield first wall fusionreactor

用二维计算机模拟作类三极管特性的结栅场效应晶体管的最佳设计

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微纳电子技术 1978年第5期 41-53页

作者： k.yamaguchi 何黎珲

利用二维数字分析法研究了类三极管特性的结栅场效应晶体管（JFET）的设计准则。电流是由越过势垒进入到耗尽沟道的载流子产生的。与一般类五极管特性的FFT相比,漏电场起重要作用,它减低势垒高度,从而形成了类三极管的I-V特性。类三极... 详细信息

利用二维数字分析法研究了类三极管特性的结栅场效应晶体管（JFET）的设计准则。电流是由越过势垒进入到耗尽沟道的载流子产生的。与一般类五极管特性的FFT相比,漏电场起重要作用,它减低势垒高度,从而形成了类三极管的I-V特性。类三极管特性强烈地依赖于器件几何结构。这种工作模式只能在短栅器件中得以实现。沟道厚度α在决定器件工作模式时是极重要的参数。作为类三极管或类五极管特性的器件工作分别对应于窄沟道或宽沟道。如果运用于低阻负载直接驱动电路,那么处于类三极管和类五极管特性之间的混合特性比单纯的类三极管特性更为理想。这是因为它具有低的内阻和高的交流功率效率。栅-漏距离lgd在决定击穿电压中也是很重要的参数。讨论了设计准则,并详细说明了在ND-a和ND-lgd平面上关于类三极管特性、电路运用和击穿现象的最佳设计。发现,无需采用任何校准参数,计算和实验结果即很好的符合。本文给出的设计准则对于类三极管的设计将是有用的。

关键词：三极管 JFET 五极管击穿电压沟道耗尽区二维

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垂直结型栅场效应晶体管的二维分析

微纳电子技术 1977年第4期 48-54页

作者： k.yamaguchi 张木义

垂直结型栅场效应晶体管是一种新型大功率器件。它们显示不同于一般场效应晶体管而类似于三极管的特性。本文应用二维数值分析研究了垂直场效应晶体管（V-FET）的类三极管的运用。这个分析表明,沟道被栅势垒耗尽对类三极管运用是一个必... 详细信息

垂直结型栅场效应晶体管是一种新型大功率器件。它们显示不同于一般场效应晶体管而类似于三极管的特性。本文应用二维数值分析研究了垂直场效应晶体管（V-FET）的类三极管的运用。这个分析表明,沟道被栅势垒耗尽对类三极管运用是一个必要条件。它也表明了栅间距 d 和栅-漏长度 lgd对垂直场效应晶体管的类三极管运用有很大的影响。由类三极管到五极管特性的转变大约是通过增加 d 或 lgd而引起的。雪崩击穿电压强烈地依赖于电场分布,并且这也是二维分析的很好题目。就有关类三极管的运用和击穿,讨论了垂直场效应晶体管的设计准则。

关键词：场效应晶体管 FET 五极管单极晶体管场效应器件击穿电压三极管二维分析

A plant growth chamber system equipped with aerosol generators for studying aerosol-vegetation interactions

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Particuology 2024年第2期85卷 122-132页

作者： Masao Gen Seiji Ikawa Masahiro yamaguchi Fong Zyin Lim Takeshi Izuta I.Wuled Lenggoro Graduate School of Bio-Applications and Systems Engineering Tokyo University of Agriculture and TechnologyKoganeiTokyo184-8588Japan Institute of Multidisciplinary Research for Advanced Materials Tohoku UniversitySendai980-8577Japan Faculty of Agriculture Tokyo University of Agriculture and TechnologyFuchuTokyo183-8509Japan Graduate School of Fisheries and Environmental Sciences Nagasaki UniversityNagasaki852-8521Japan Institute of Agriculture Tokyo University of Agriculture and TechnologyFuchuTokyo183-8509 Japan Department of Applied Physics and Chemical Engineering Tokyo University of Agriculture and TechnologyKoganeiTokyo184-8588Japan Institute of Global Innovation Research Tokyo University of Agriculture and TechnologyFuchuTokyo183-8509Japan

Understanding aerosol-vegetation interactions is vital in ***,the interactions remain elusive partly due to the lack of suitable plant growth chamber ***,deposition of submicron particles on leaf surfaces is challenging due to its low deposition velocities compared to larger *** this work,we present a plant-growth chamber that was used to study the effect of sub-micron black carbon(BC)particles on the growth and photosynthesis of *** chamber system simultaneously enables the growth of multiple plants in pots and the deposition of submicron particles onto *** spraying methods assisted by ultrasonic and electrostatic forces were employed as aerosol generators to realize the particle *** flow regime inside the chamber was numeri-cally calculated to predict the transportation of aerosol particles,suggesting the optimal operating conditions of the *** gas-phase particle size distribution measurements showed that gener-ated BC particles were suspended in submicron diameter *** aerosol generators were examined in the chamber using three conductor and insulator substrates as a model of plant *** observations and spectroscopic analysis ascertained that submicron BC particles generated from our generators were deposited on all substrate *** the developed chamber system,systematic studies can be performed to advance the fundamental understanding of aerosol-vegetation interactions.

关键词： Aerosol Exposure chamber Spray drying Black carbon

Bi-predual spaces of generalized Campanato spaces with variable growth condition

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Acta Mathematica Sinica,English Series 2024年

作者： Satoshi yamaguchi Eiichi NAkAI katsunori SHIMOMURA Department of Mathematics Ibaraki University

In this paper we extend the duality(■)*= H1(Rd) to generalized Campanato spaces with variable growth condition Lp,φ(Rd) instead of BMO(Rd). We also extend the characterization of Cc∞omp(Rd)BMO(Rd)by Uchiyama(1978) to ■. Moreover, using this characterization, we prove the boundedness of singular and fractional integral operators on ■.The function space Lp,φ(Rd) treated in this paper covers the case that it is coincide with Lipαon one area, with BMO on another area and with the Morrey space on the other area, for example.

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Computer-controlled ultra high voltage amplifier for dielectric elastomer actuators

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Biomimetic Intelligence & Robotics 2024年第1期4卷 14-23页

作者： Ardi Wiranata Zebing Mao Yu kuwajima Yuya yamaguchi Muhammad Akhsin Muflikhun Hiroki Shigemune Naoki Hosoya Shingo Maeda Department of Mechanical and Industrial Engineering University of Gadjah MadaYogyakarta 55281Indonesia Department of Mechanical Engineering Tokyo Institute of TechnologyTokyo 152-8550Japan Department of Engineering and Science Shibaura Institute of TechnologyTokyo 135-8548Japan Department of Electrical Engineering Shibaura Institute of TechnologyTokyo 135-8548Japan Department of Engineering Science and Mechanics Shibaura Institute of TechnologyTokyo 135-8548Japan Living Systems Materialogy(LiSM)Research Group International Research Frontiers Initiative(IRFI)Tokyo Institute of TechnologyYokohama 226-8501Japan

Soft robotics is a breakthrough technology to support human-robot *** soft structure of a soft robot can increase safety during human and robot *** of the promising soft actuators for soft robotics is dielectric elastomer actuators(DEAs).DEAs can operate silently and have an excellent energy *** simple structure of DEAs leads to the easy fabrication of soft *** simplicity combined with silent operation and high energy density make DEAs interesting for soft robotics *** actuation follows the Maxwell-pressure *** pressure produced in the DEAs actuation depends much on the voltage *** DEAs requires high voltage to gain an *** the power consumption of DEAs is in the milli-Watt range,the current needed to operate the DEAs can be *** commercially available DC-DC converters can convert the volt range to the kV *** order to get a voltage in the 2-3 kV range,the reliable DC-DC converter can be pricy for each *** problem hinders the education of soft actuators,especially for a newcomer laboratory that works in soft electric *** paper introduces an entirely do-it-yourself(DIY)Ultrahigh voltage amplifier(UHV-Amp)for education in soft ***-Amp can amplify 12 V to at a maximum of 4 kV *** a demonstration,we used this UHV-Amp to test a single layer of powdered-based *** strategy to build this educational type UHV-Amp was utilizing a Cockcroft-Walton circuit structure to amplify the voltage range to the kV *** its current state,the UHV-Amp has the potential to achieve approximately 4 *** created a simple platform to control the UHV-Amp from a personal *** near future,we expect this easy control of the UHV-Amp can contribute to the education of soft electric actuators.

关键词： Dielectric elastomer actuators Electric amplifier Soft actuators Soft robotics Soft actuator education

The neutrophil–osteogenic cell axis promotes bone destruction in periodontitis

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International Journal of Oral Science 2024年第1期16卷 154-162页

作者： Yutaro Ando Masayuki Tsukasaki Nam Cong-Nhat Huynh Shizao Zang Minglu Yan Ryunosuke Muro kazutaka Nakamura Masatsugu komagamine Noriko komatsu kazuo Okamoto kenta Nakano Tadashi Okamura Akira yamaguchi kazuyuki Ishihara Hiroshi Takayanagi Department of Immunology Graduate School of Medicine and Faculty of MedicineThe University of Tokyo7-3-1HongoBunkyo-kuTokyoJapan Department of Microbiology Tokyo Dental College2-1-14 Kanda-Misaki-choChiyoda-kuTokyoJapan Oral Health Science Center Tokyo Dental College2-9-18Kanda-Misaki-choChiyodakuTokyoJapan Department of Osteoimmunology Graduate School of Medicine and Faculty of MedicineThe University of Tokyo7-3-1HongoBunkyo-kuTokyoJapan Unit of Prosthodontics Laboratory of Oral-Maxillofacial Biology Faculty of Odonto-StomatologyUniversity of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh CityVietnam Department of Oral and Maxillofacial Surgery Department of Sensory and Motor System MedicineGraduate School of MedicineThe University of TokyoTokyoJapan Division of Rheumatology Department of Internal MedicineKeio University School of MedicineTokyoJapan Department of Laboratory Animal Medicine Research InstituteNational Center for Global Health and MedicineTokyoJapan

The immune-stromal cell interactions play a key role in health and diseases. In periodontitis, the most prevalent infectious disease in humans, immune cells accumulate in the oral mucosa and promote bone destruction by inducing receptor activator of nuclear factor-κB ligand (RANkL) expression in osteogenic cells such as osteoblasts and periodontal ligament cells. However, the detailed mechanism underlying immune–bone cell interactions in periodontitis is not fully understood. Here, we performed single-cell RNAsequencing analysis on mouse periodontal lesions and showed that neutrophil–osteogenic cell crosstalk is involved in periodontitis-induced bone loss. The periodontal lesions displayed marked infiltration of neutrophils, and in silico analyses suggested that the neutrophils interacted with osteogenic cells through cytokine production. Among the cytokines expressed in the periodontal neutrophils, oncostatin M (OSM) potently induced RANkL expression in the primary osteoblasts, and deletion of the OSM receptor in osteogenic cells significantly ameliorated periodontitis-induced bone loss. Epigenomic data analyses identified the OSM-regulated RANkL enhancer region in osteogenic cells, and mice lacking this enhancer showed decreased periodontal bone loss while maintaining physiological bone metabolism. These findings shed light on the role of neutrophils in bone regulation during bacterial infection, highlighting the novel mechanism underlying osteoimmune crosstalk.

关键词： period neutrophil destruction

Static Stretching Combined with Conscious Slower Breathing May Increase Parasympathetic Activity and Reduce Stress in Adult Women

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Health 2024年第3期16卷 242-256页

作者： Mami Sakurai Yasushi Ikarashi Masahiro Tabuchi Ailing Hu Takuji yamaguchi Hiroyuki kobayashi Department of Hospital Administration Juntendo University Graduate School of Medicine Tokyo Japan Department of Beauty & Wellness Professional University of Beauty & Wellness Yokohama Japan Department of Personalized kampo Medicine Juntendo University Graduate School of Medicine Tokyo Japan

Background: Women are thought to be more susceptible to stress than men in a stressful society, and reducing stress is crucial for women to maintain their health. Static stretching (SST) is applied in various fields to not only increase muscle flexibility but also reduce stress. Additionally, conscious slower breathing (CSB) predominates parasympathetic activity, causing a relaxing effect. These results indicate that combining SST and CSB may be more useful in reducing stress. However, to the best of our knowledge, the effect of this combination remains unclear. Objective: This study aimed to elucidate the effects of the combination of SST and CSB on autonomic activity and stress in adult women. Methods: Eleven healthy Japanese adult female participants performed SST with nonconscious natural breathing for 20 min. The same participants performed SST in combination with CSB (2 s inspiratory and 4 s expiratory) for 20 min on another day. Salivary cortisol and chromogranin A levels were measured before and after stretching as stress markers of the hypothalamic-pituitary-adrenal axis and sympathetic nervous system. The coefficient of variation of the R-R interval (CVR-R) and high-frequency component (HF), which reflect parasympathetic nerve activity, and heart rate and low-frequency component (LF)/HF ratio, which reflect sympathetic nerve activity, were measured before, during, and after stretching. Results: SST decreased cortisol levels but with no significant changes in chromogranin A, heart rate, CVR-R, HF, or LF/HF ratio. The combination of SST and CSB increased CVR-R and HF levels in addition to decreasing cortisol levels but with no significant changes in chromogranin A, heart rate, or LF/HF levels. Conclusion: These results indicate that the combination of SST and CSB may increase parasympathetic activity and reduce stress. However, future randomized controlled trials with larger sample sizes should support this conclusion.

关键词： Static Stretching Conscious Slower Breathing Autonomic Activity Heart Rate Variability Stress