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Optimization of Crystal Structure Based on Experimentally Obtained XRD Patterns for Fluorescence of Sm³⁺-Doped TiO₂ Thin Films by Machine Learning

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Optics and Photonics Journal 2022年第6期12卷 147-155页

作者： Yuri Tamamoto mariko murayama Xiwei Zhao Department of Physics Tokyo University of Science Tokyo Japan Research Institute of Industrial Technology Toyo University Saitama Japan Department of Materials Science and Engineering Xihua University Chengdu China

The luminescence intensity of rare-earth ion-doped luminescent materials is closely related to the configuration of the anions around the rare-earth ions added to the host material and the lattice defects. And it is expected that this information will be reflected in the XRD pattern. In this study, the lumines-cence data and XRD patterns of Sm-doped TiO2 accumulated by our group are used to construct a model to predict the integrated luminescence intensity. The model was confirmed to be able to predict the integrated luminescence in-tensity with high accuracy. Furthermore, we found that the integrated lumi-nescence intensity of this system is closely related to the change in the position of the peak on the (200) plane of TiO2.

关键词： Machine Learning Phosphor TiO2

Annealing Temperature-Dependent Luminescence Color Coordination in Eu-Doped AlN Thin Films

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Journal of Materials Science and Chemical Engineering 2024年第1期12卷 20-28页

作者： Yingda Qian mariko murayama Sujun Guan Xinwei Zhao Department of Physics Tokyo University of Science Tokyo Japan Research Center for Space System Innovation Tokyo University of Science Chiba Japan

AlN was used as a host material and doped with Eu grown on Si substrate by pulsed laser deposition (PLD) with low substrate temperature. The X-ray diffraction (XRD) data revealed the orientation and the composition of the thin film. The surface morphology was studied by scanning electron microscope (SEM). While raising the annealing temperatures from 300˚C to 900˚C, the emission was observed from AlN: Eu under excitation of 260 nm excitation. The photoluminescence (PL) was integrated over the visible light wavelength shifted from the blue to the red zone in the CIE 1931 chromaticity coordinates. The luminescence color coordination of AlN: Eu depending on the annealing temperatures guides the further study of Eu-doped nitrides manufacturing on white light emitting diode (LED) and full color LED devices.

关键词： Low-Temperature PLD Growth Eu-Doped AlN Thin Film White Light Emitting Diode

Synthesis and Conductivity Characterization of Anti-Perovskite Na₃OX Solid Electrolytes for All Solid Na-Ion Batteries

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Optics and Photonics Journal 2023年第7期13卷 189-198页

作者： Wei Shi Masataka Ohta Hiroaki Asakawa Yuki Osaki mariko murayama Xinwei Zhao Department of Physics Tokyo University of Science Tokyo Japan Faculty of Science and Engineering Toyo University Saitama Japan International Institute for Urban Systems Engineering Southeast University Nanjing China

Solid electrolytes for all solid sodium-ion batteries have been attracting much attention as an alternative energy storage system, which have the advantage of being extremely safe because it can be charged quickly and is nonflammable. We have synthesized anti-perovskite type Na3OX (X = Br, and I) electrolytes with high purity, by reactions of halogen mixtures with sodium oxides. After mixing, it was filled in an alumina crucible and heated for 6 hours at 330°C. It was confirmed that a large crystal strain was introduced by eutectication, which might reduce the activation energy of Na ion conduction and lead to an improvement of the conductivity. A relatively higher ionic conductivity of σ = 1.55 × 10-7 S/cm at 60°C has been obtained for Na3OBr0.6I0.4, which is about three orders higher than that in literature. A different ratio of X (X = Br, I) ions was added into sodium oxide to make the Na3OX crystal. The influence of strain introduction on optimizing the bottleneck and improving the conductivity was discussed.

关键词： Sodium Ion Battery Solid Electrolyte Ionic Conductivity Anti-Perovskite

Improved Interface of Encapsulating Sm-Doped TiO₂ Thin Films/RuO₂ Schottky Diodes for a Junction Spectropy Measurement

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Optics and Photonics Journal 2022年第10期12卷 215-224页

作者： mariko murayama Yuri Tamamoto Yingda Qian Asuka Ishizawa Simon Hammersley Iain F. Crowe Shuji Komuro Shuji Komuro Xinwei Zhao Department of Physics Tokyo University of Science Tokyo Japan Research Institute of Industrial Technology Toyo University Saitama Japan Photon Science Institute and School of Electrical and Electronic Engineering University of Manchester Manchester UK

The excitation process of rare-earth ions in oxide semiconductors for optical emission is thought to be related to defect levels within the band-gap of the host material. In order to improve understanding of the role defect levels play in the energy transfer process, junction spectroscopy techniques can be used to investigate the electrically active emission centres. It has been reported that TiO2 is sensitive to humidity at low temperatures, such as those employed when conducting junction spectroscopy measurements. However, there are not many discussions how to prevent this effect and to improve the quality of measurements. After optimization of samples such as fabrication of flat surface and encupsulant for preventing external effect, temperature dependent-capacitance measurements (C-T) were carried out to characterise shallow traps formed within TiO2 band-gap. TiO2 and Sm-doped TiO2 thin films were deposited on SrTiO3 (100) templates by laser ablaton and rectifying Ruthenium Oxide Schottky diodes deposited on the TiO2 surface by laser ablation. A Sm or Sm-related shallow trap was observed in the Arrhenius plot of TiO2:Sm. In this paper, we show the optimized sample fabrication/preparation process that stabilizes the junction spectroscopy measurements, even in the presence of humidity and we present initial results obtained on samples using these optimized processing techniques.

关键词： Rare Earth TiO2 Photoluminescence Junction Spectroscopy

Capillary method for measuring near-infrared spectra of microlitre volume liquids

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第2期8卷 171-175页

作者： YUAN Bo murayama Koichi Department of Information Science and Optoelectronic Engineering State Key Laboratory of Modern Optical Instrumentation CNERC for Optical Instrument Zhejiang University Hangzhou 310027 China Department of Biochemistry and Biophysics Gifu University School of Medicine Gifu 500-8705 Japan

The present study theoretically explored the feasibility of the capillary method for measuring near-infrared (NIR) spectra of liquid or solution samples with microlitre volume, which was proposed in our previous studies. Lambert-Beer absorb- ance rule was applied to establish a model for the integral absorbance of capillary, which was then implemented in numerical analyses of the effects of capillary on various spectral features and dynamic range of absorption measurement. The theoretical speculations indicated that the capillary method might be used in NIR spectroscopy, which was further supported by the empirical data collected from our experiments by comparison between capillary NIR spectra of several organic solvents and cuvette cell NIR spectra.

关键词： Near-infrared (NIR) spectroscopy Capillary Cuvette cell Numerical analysis

A comparative study of land price estimation and mapping using regression kriging and machine learning algorithms across Fukushima prefecture,Japan

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Journal of Geographical Sciences 2020年第5期30卷 794-822页

作者： DERDOURI Ahmed murayama Yuji Division of Spatial Information Science Graduate School of Life and Environmental SciencesUniversity of TsukubaTennodaiTsukubaIbarakiJapan Faculty of Life and Environmental Sciences University of TsukubaTennodaiTsukubaIbarakiJapan

Finding accurate methods for estimating and mapping land prices at the macro-scale based on publicly accessible and low-cost spatial data is an essential step in producing a meaningful reference for regional *** asset would assist them in making economically justified decisions in favor of key investors for development projects and post-disaster recovery *** 2005,the Ministry of Land,Infrastructure,and Transport of Japan has made land price data open to the public in the form of observations at dispersed *** this data is useful,it does not provide complete information at every site for all market ***,estimating and mapping land prices based on sound statistical theories is *** paper presents a comparative study of spatial prediction of land prices in 2015 in Fukushima prefecture based on geostatistical methods and machine learning *** use,elevation,and socioeconomic factors,including population density and distance to railway stations,were used for *** show the superiority of the random forest ***,land prices are distributed unevenly across the prefecture with the most expensive land located in the western region characterized by flat topography and the availability of well-connected and highly dense economic hotspots.

关键词： land price spatial estimation kriging machine learning Fukushima prefecture,Japan

Grain size altering yielding mechanisms in ultrafine grained high-Mn austenitic steel:Advanced TEM investigations

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Journal of Materials Science & Technology 2021年第27期86卷 192-203页

作者： Chang-Yu Hung Yu Bai Nobuhiro Tsuji Mitsuhiro murayama Department of Materials Science and Engineering Virginia TechBlacksburgVA24061USA Department of Materials Science and Engineering Kyoto UniversityYoshida-honmachiSakyo-kuKyoto606-8501Japan Elements Strategy Initiative for Structural Materials Kyoto UniversityYoshida-honmachiSakyo-kuKyoto606-8501Japan Institute for Materials Chemistry and Engineering Kyushu UniversityKasugaFukuoka8168580Japan

The underlying mechanism of discontinuous yielding behavior in an ultrafine-grained(UFG)Fe-31 Mn-3 Al-3 Si(wt.%)austenitic TWIP steel was investigated by the use of advanced TEM technique with taking the plastic deformation mechanisms and their correlation with grains size near the macroscopic yield point into *** yield drop mechanisms such as the dislocation locking by the Cottrell atmosphere due to the presence of interstitial impurities cannot explain the origin of this phenomenon in the UFG high-Mn austenitic TWIP ***,we experimentally revealed that the plastic deformation mechanisms in the early stage of deformation,around the macroscopic yield point,show an obvious association with grain *** specifically,the main mechanism shifts from the conventional slip in grain interior to twinning nucleated from grain boundaries with decreasing the grain size down to less than 1μ*** observation indicates that the grain size dependent deformation mechanisms transition is also deeply associated with the discontinuous yielding behavior as it could govern the changes in the grain interior dislocation density of mobile dislocations around the macroscopic yield point.

关键词： Ultrafine grains TWIP steel Yield-drop phenomenon Deformation twin nucleation Structural defects Transmission electron microscopy

Novel CD9-targeted therapies in gastric cancer

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World Journal of Gastroenterology 2015年第11期21卷 3206-3213页

作者： Yoko murayama Kenji Oritani Shusaku Tsutsui Department of Gastro-enterology and Hepatology Itami City Hospital Department of Hematology/Oncology Graduate School of MedicineOsaka University

There are 33 human tetraspanin proteins,emerging as key players in malignancy,the immune system,fertilization,cellular signaling,adhesion,morphology,motility,proliferation,and tumor ***9,a member of the tetraspanin family,associates with and influences a variety of cell-surface *** these interactions,CD9 modifies multiple cellular events,including adhesion,migration,proliferation,and ***9 is therefore considered to play a role in several stages during cancer *** CD9 expression is generally related to venous vessel invasion and metastasis as well as poor *** found that treatment of mice bearing human gastric cancer cells with anti-CD9 antibody successfully inhibited tumor progression via antiproliferative,proapoptotic,and antiangiogenic effects,strongly indicating that CD9 is a possible therapeutic target in patients with gastric ***,we describe the possibility of CD9 manipulation as a novel therapeutic strategy in gastric cancer,which still shows poor prognosis.

关键词： CD9 Tetraspanin Gastric cancer Tumo-rigenicity The

Structural Health Monitoring by Using Fiber-Optic Distributed Strain Sensors With High Spatial Resolution

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Photonic Sensors 2013年第4期3卷 355-376页

作者： Hideaki murayama Daichi WADA Hirotaka IGAWA School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan Japan Aerospace Exploration Agency 6-13-10hsawa Mitaka Tokyo 181-0015 Japan

In this paper, we review our researches on the topics of the structural health monitoring （SHM） with the fiber-optic distributed strain sensor. Highly-dense information on strains in a structure can be useful to identify some kind of existing damages or applied loads in implementation of SHM. The fiber-optic distributed sensors developed by the authors have been applied to the damage detection of a single-lap joint and load identification of a beam simply supported. We confirmed that the applicability of the distributed sensor to SHM could be improved as making the spatial resolution higher. In addition, we showed that the simulation technique considering both structural and optical effects seamlessly in strain measurement could be powerful tools to evaluate the performance of a sensing system and design it for SHM. Finally, the technique for simultaneous distributed strain and temperature measurement using the PANDA-fiber Bragg grating （FBG） is shown in this paper, because problems caused by the cross-sensitivity toward strain and temperature would be always inevitable in strain measurement for SHM.

关键词： Structural health monitoring fiber-optic distributed sensor strain monitoring damage detection load identification