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Journal of Materials Science and Chemical Engineering 2017年第12期5卷 52-62页

作者： ken-Ichi hirota Masahiko Maeda College of Engineering Kanazawa Institute of Technology Ishikawa Japan

In order to clarify the visible-light responsive photocatalysis of TiO2 co-doped with Cu and N atoms, plasma-nitridation was taken place to Cu-doped TiO2 film. Cu-doped TiO2 films were prepared by dip-coating method and they were nitrided by nitrogen plasma in the plasma-enhanced CVD system. Cu-doped TiO2 films before and after plasma-nitridation show similar X-ray diffraction peaks of anatase TiO2. XPS analysis reveals that the ionic states of Ti and Cu in the Cu-doped TiO2 films are Ti4+ and Cu+, respectively. After nitrogen plasma treatment, oxygen atoms are released by substitution of nitrogen atoms in the TiO2 matrix, so that Cu+ is oxidized to generate Cu2+ and at the same time oxygen vacancy is formed. The absorption edge of both Cu-doped and plasma-nitrided Cu-doped TiO2 did red shift. Visible-light responsive photocatalytic activity of the Cu-doped TiO2 film degraded after nitrogen plasma treatment.

关键词： Sol-Gel Cu-Doped Titania Plasma-Nitridation Photocatalysis

Fabrication of ZrC/ZrB₂/C Composites Having High Mechanical Properties at Elevated Temperatures

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Materials Sciences and Applications 2022年第4期13卷 232-248页

作者： Kai Matsumoto Masaki Kato ken hirota Toshiyuki Nishimura Department of Molecular Chemistry & Biochemistry Faculty of Science & Engineering Doshisha University Kyotanabe Japan National Institute for Materials Science Tsukuba Japan

Ultra-high temperature ceramics (UHTCs) are most recently getting much attention for structural parts of hypersonic missiles with their cruising speed of more than Mach 5. Most of the UHTCs are poor sinterability carbides, nitrides, and borides. Therefore, they have been studied and developed for a long time. However, there are still many problems to solve. In this paper, based on the solid-state reaction presented as an equation of (x + y)·ZrC + 2·y·B → x·ZrC + y·ZrB2 + y·C, three-phase ZrC/ZrB2/C composites have been fabricated from ZrC and amorphous B powders using pulsed electric-current pressure sintering at 1373 to 2173 K for 6.0 × 102 s under 50 MPa in a vacuum. ZrC/ZrB2/C = 30/70/C~70/30/C vol% composites with the relative densities Dr of 96.6 to 98.7% were obtained at 2073 K. The 60/40/C vol% composite revealed high bending strength σb (554 MPa), Vickers hardness Hv (19.2 GPa) and moderate fracture toughness KIC (5.25 MPa·m1/2) at room temperature. Furthermore, all composites showed elastic deformation up to 1873 K and revealed σb more than 600 MPa at this temperature, in addition, some composites showed higher σb than 900 MPa at the same temperature. These high mechanical behaviors are discussed with those of the simple binary ZrC/ZrB2 composites which were fabricated under the same conditions except for their starting materials. The best mechanical properties of binary composites were σb (474 MPa), Hv (18.5 GPa), and KIC (4.45 MPa·m1/2) at room temperature, and σb of 400 - 700 MPa at 1873 K. Overall, three-phase composites, nevertheless including soft carbon, have higher mechanical properties than the binary composites.

关键词： ZrC ZrB2 C Composites Pulsed Electric-Current Pressure Sintering Mechanical Properties

Evaluation of Reactive Oxygen Species (ROS) Generated on the Surface of Copper Using Chemiluminesence

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Materials Sciences and Applications 2023年第10期14卷 482-499页

作者： ken hirota Hiroya Tanaka Taika Maeda Kazuhiko Tsukagoshi Hiroshi Kawakami Takashi Ozawa Masahiko Wada Research Center of Bio-Micro-Fluidic Science Doshisha University Kyoto Japan Department of Chemical Engineering and Materials Science Faculty of Science & Engineering Doshisha University Kyoto Japan Graduate School of Engineering College of Engineering Osaka Metropolitan University Osaka Japan Japan Copper Development Association Tokyo Japan

The antibacterial activity of copper is well-known from an ancient civilization, however, its biocidal mechanism has not been necessarily elucidated. Notwithstanding up to now, mainly 4 processes have been proposed. Among them, it is cleared that 4 kinds of reactive oxygen species (ROS): hydroxyl radical ·OH, hydrogen per oxide H2O2, superoxide anion ·O-2 and singlet oxygen 1O2, play an important role for contact-killing of bacteria, viruses and fungi. In this paper, generation of ROS on the surfaces of copper plates heated from room temperature to 673 K for 4.2 × 102 s in air, was investigated using the chemiluminescence. ROS have been evaluated by selecting the most suitable scavengers, such as 2-propanol for ·OH, sodium pyruvate for H2O2, nitro blue tetrazolium for ·O-2, and sodium azide NaN3 for 1O2. At the same time the outermost surface of copper, on which thin film of cuprous oxide Cu2O was first formed and then cupric oxide CuO was laminated on Cu2O, was examined by thin-film XRD and TEM analysis to estimate the amounts and kinds of copper oxides. It was found that the most amounts of ROS were obtained for the 573 K-heated Cu plate and they were composed of ·OH, H2O2, and ·O-2..

关键词： Copper Microbial Activity Reactive Oxygen Species Chemiluminescence Scavengers

Preparation of Anatase Titanium Dioxide Nanoparticle Powders Submitting Reactive Oxygen Species (ROS) under Dark Conditions

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Materials Sciences and Applications 2021年第2期12卷 89-110页

作者： Thi Minh Phuong Nguyen Perrine Lemaitre Masaki Kato ken hirota Kazuhiko Tsukagoshi Hirohisa Yamada Atsuki Terabe Hideto Mizutani Shingo Kanehira Applied Chemistry Graduate School of Science and Engineering Doshisha University Kyoto Japan Department of Chemical Engineering National Institute of Technology Nara College Nara Japan Sakai Chemical Industry Co. Ltd. Sakai Japan Microwave Chemical Co. Ltd. Osaka Japan

Recently, under the circumstances of pandemic of COVID-19 much attention has been paid to titanium dioxide TiO2 as bactericidal agent;however, conventional TiO2 requires ultraviolet radiation or visible light to exercise its photocatalytic properties and its induced antimicrobial activity. In order to expand its applications directed at wide civil life, antibacterial TiO2 being usable under dark conditions has been demanded. The present paper describes the powder characterization of newly developed potassium K and phosphorous P co-doped nanometer-size anatase TiO2 powders using X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM & TEM), Brunauer-Emmett-Teller method (BET), fourier-transform infrared spectroscopy (FT-IR), X-ray absorption fine structure (XAFS), electron spin resonance (ESR) and chemiluminescence (CL). It was found for the first time that thus prepared anatase TiO2 could submit much reactive oxygen species (ROS) even in the dark, which has close relation with bactericidal activity in light interception.

关键词： Anatase Microbial Activity under Dark Conditions Potassium K Phosphorous P

应用经食道超声心动图评估局部肺血流的新方法

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麻醉与镇痛 2009年第3期5卷 41-45页

作者： Yuichi Yatsu Toshihito Tsubo Hironori Ishihara Hitomi Nakamura Kazuyoshi hirota 吴洁(译) Department of Anesthesiology University of Hirosaki School of Medicine Hirosaki Aomori-ken Japan 不详

背景我们已经报道过在试验狗模型中应用经食道超声心动图探测不张肺局部血流的新方法。为证实此方法的有效性，我们就该方法对肺局部血流变化的探测能力进行了研究。方法14只麻醉后机械通气的杂种狗随机分为异丙肾上腺素组和多巴胺组，... 详细信息

背景我们已经报道过在试验狗模型中应用经食道超声心动图探测不张肺局部血流的新方法。为证实此方法的有效性，我们就该方法对肺局部血流变化的探测能力进行了研究。方法14只麻醉后机械通气的杂种狗随机分为异丙肾上腺素组和多巴胺组，每组7只。为造成肺不张损伤模型，将60ml／kg生理盐水输入左侧胸膜腔。由脉冲多普勒推导出速度时间积分（VTI）作为评价不张肺损伤血流的指标。为研究此方法对于肺血流变化的反应程度，在按0．05μg·kg^-1·min^-1输注异丙肾上腺素（作为肺血管扩张剂）和按10μg·kg^-1·min^-1输注多巴胺（作为肺血管收缩剂）时测量收缩期VTI和肺分流比（Qs／Qt）。结果应用异丙肾上腺素后VTI和Qs／Qt均显著增加，且VTI变化百分数和Qs／Qt存在显著的相关性（r^2=0．50，P〈0．001）．而VTI和Qs／Qt在应用多巴胺后均无改变。结论经食道超声心动图可有效用于肺不张局部肺血流变化的检测。

关键词：经食道超声心动图肺血流异丙肾上腺素评估血流变化肺血管扩张剂脉冲多普勒血管收缩剂