The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Ryoji Kanno - One of the best experts on this subject based on the ideXlab platform.
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epitaxial growth and electrochemical properties of li4ti5o12 thin film lithium battery anodes
Dalton Transactions, 2011Co-Authors: Masaaki Hirayama, Takeshi Toujigamori, Ryoji KannoAbstract:Epitaxial Li4Ti5O12 thin-films were successfully synthesized on SrTiO3 single-crystal substrates with (111), (110), and (100) Lattice Plane orientations using pulsed laser deposition (PLD). Thin-film X-ray diffraction (XRD) revealed that the Li4Ti5O12 films had the same orientation as the SrTiO3 substrates: Li4Ti5O12 (111) on SrTiO3 (111), Li4Ti5O12 (110) on SrTiO3 (110), and Li4Ti5O12 (100) on SrTiO3 (100). These epitaxial films contained island structures, and the morphology of the (111), (110), and (100) films, observed by field emission scanning electron microscopy (FE-SEM), exhibited angular, needle-like, and circular shapes, respectively. The electrochemical properties of 20 nm thick Li4Ti5O12 (111) and (110) films were investigated by cyclic voltammetry. Reversible intercalation proceeded through both Lattice Planes due to the three-dimensional diffusion pathway of lithium in the spinel framework. Reduction peaks in the first cathodic scan appeared at different positions from those in subsequent scans, suggesting a surface reconstruction at the Li4Ti5O12 surface due to interfacial reactions.
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characterization of electrode electrolyte interface with x ray reflectometry and epitaxial film limn2o4 electrode
Journal of The Electrochemical Society, 2007Co-Authors: Masaaki Hirayama, Noriyuki Sonoyama, Machiko Minoura, Masumi Ito, Daisuke Mori, Atsuo Yamada, Kazuhisa Tamura, Junichiro Mizuki, Ryoji KannoAbstract:Structural changes at electrode/electrolyte interface of a lithium cell were studied by X-ray reflectometry and two-dimensional model electrodes with a restricted Lattice Plane of LiMn 2 O 4 . The electrodes were constructed with an epitaxial film synthesized by the pulsed laser deposition method. The orientation of the film depends on the substrate Plane; the (111), (110), and (100) Planes of LiMn 2 O 4 grew on the (111), (110), and (100) Planes of the SrTiO 3 substrates, respectively. The ex situ reflectometry indicated that a thin impurity layer covered the Lattice Plane of the as-grown film. The impurity layer was dissolved and a solid-electrolyte-interface-like phase appeared after the electrode was soaked into the electrolyte. A defect layer was formed in the (111) Plane, whereas no density changes were detected for the other Lattice Planes. The in situ observation clarified that the surface reactivity depended on the Lattice Planes of the spinel; the defect layer at the (111) Plane was stable during the electrochemical reaction, whereas a slight decrease in the film thickness was observed for the (110) Plane. Our surface characterization of the intercalation electrode indicated that the surface structure changes during the pristine stage of the change-discharge processes and these changes are dependent on the Lattice orientation of LiMn 2 O 4 .
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characterization of electrode electrolyte interface for lithium batteries using in situ synchrotron x ray reflectometry a new experimental technique for licoo2 model electrode
Journal of Power Sources, 2007Co-Authors: Masaaki Hirayama, Noriyuki Sonoyama, Takeshi Abe, Machiko Minoura, Masumi Ito, Daisuke Mori, Atsuo Yamada, Ryoji Kanno, T Terashima, Mikio TakanoAbstract:Abstract A new experimental technique was developed for detecting structure changes at electrode/electrolyte interface of lithium cell using X-ray reflectometry and two-dimensional model electrodes with a restricted Lattice-Plane. The electrodes were constructed with an epitaxial film of LiCoO2 synthesized by pulsed laser deposition method. The orientation of the epitaxial film depends on the substrate Plane; the 2D layer of LiCoO2 is parallel to the SrTiO3 (1 1 1) substrate ( ( 0 0 3 ) LiCo O 2 / / ( 1 1 1 ) SrTi O 3 ) , while the 2D layer is perpendicular to the SrTiO3 (1 1 0) substrate ( ( 1 1 0 ) LiCo O 2 / / ( 1 1 0 ) SrTi O 3 ) . The anisotropic properties were confirmed by electrochemical measurements. Ex situ X-ray reflectivity measurements indicated that the impurity layer existed on the as-grown LiCoO2 was dissolved and a new SEI layer with lower density was formed after soaking into the electrolyte. In situ X-ray reflectivity measurements indicated that the surface roughness of the intercalation (1 1 0) Plane increased with applying voltages, while no significant changes in surface morphology were observed for the intercalation non-active (0 0 3) Plane during the pristine stage of the charge–discharge process.
Masaaki Hirayama - One of the best experts on this subject based on the ideXlab platform.
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epitaxial growth and electrochemical properties of li4ti5o12 thin film lithium battery anodes
Dalton Transactions, 2011Co-Authors: Masaaki Hirayama, Takeshi Toujigamori, Ryoji KannoAbstract:Epitaxial Li4Ti5O12 thin-films were successfully synthesized on SrTiO3 single-crystal substrates with (111), (110), and (100) Lattice Plane orientations using pulsed laser deposition (PLD). Thin-film X-ray diffraction (XRD) revealed that the Li4Ti5O12 films had the same orientation as the SrTiO3 substrates: Li4Ti5O12 (111) on SrTiO3 (111), Li4Ti5O12 (110) on SrTiO3 (110), and Li4Ti5O12 (100) on SrTiO3 (100). These epitaxial films contained island structures, and the morphology of the (111), (110), and (100) films, observed by field emission scanning electron microscopy (FE-SEM), exhibited angular, needle-like, and circular shapes, respectively. The electrochemical properties of 20 nm thick Li4Ti5O12 (111) and (110) films were investigated by cyclic voltammetry. Reversible intercalation proceeded through both Lattice Planes due to the three-dimensional diffusion pathway of lithium in the spinel framework. Reduction peaks in the first cathodic scan appeared at different positions from those in subsequent scans, suggesting a surface reconstruction at the Li4Ti5O12 surface due to interfacial reactions.
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characterization of electrode electrolyte interface with x ray reflectometry and epitaxial film limn2o4 electrode
Journal of The Electrochemical Society, 2007Co-Authors: Masaaki Hirayama, Noriyuki Sonoyama, Machiko Minoura, Masumi Ito, Daisuke Mori, Atsuo Yamada, Kazuhisa Tamura, Junichiro Mizuki, Ryoji KannoAbstract:Structural changes at electrode/electrolyte interface of a lithium cell were studied by X-ray reflectometry and two-dimensional model electrodes with a restricted Lattice Plane of LiMn 2 O 4 . The electrodes were constructed with an epitaxial film synthesized by the pulsed laser deposition method. The orientation of the film depends on the substrate Plane; the (111), (110), and (100) Planes of LiMn 2 O 4 grew on the (111), (110), and (100) Planes of the SrTiO 3 substrates, respectively. The ex situ reflectometry indicated that a thin impurity layer covered the Lattice Plane of the as-grown film. The impurity layer was dissolved and a solid-electrolyte-interface-like phase appeared after the electrode was soaked into the electrolyte. A defect layer was formed in the (111) Plane, whereas no density changes were detected for the other Lattice Planes. The in situ observation clarified that the surface reactivity depended on the Lattice Planes of the spinel; the defect layer at the (111) Plane was stable during the electrochemical reaction, whereas a slight decrease in the film thickness was observed for the (110) Plane. Our surface characterization of the intercalation electrode indicated that the surface structure changes during the pristine stage of the change-discharge processes and these changes are dependent on the Lattice orientation of LiMn 2 O 4 .
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characterization of electrode electrolyte interface for lithium batteries using in situ synchrotron x ray reflectometry a new experimental technique for licoo2 model electrode
Journal of Power Sources, 2007Co-Authors: Masaaki Hirayama, Noriyuki Sonoyama, Takeshi Abe, Machiko Minoura, Masumi Ito, Daisuke Mori, Atsuo Yamada, Ryoji Kanno, T Terashima, Mikio TakanoAbstract:Abstract A new experimental technique was developed for detecting structure changes at electrode/electrolyte interface of lithium cell using X-ray reflectometry and two-dimensional model electrodes with a restricted Lattice-Plane. The electrodes were constructed with an epitaxial film of LiCoO2 synthesized by pulsed laser deposition method. The orientation of the epitaxial film depends on the substrate Plane; the 2D layer of LiCoO2 is parallel to the SrTiO3 (1 1 1) substrate ( ( 0 0 3 ) LiCo O 2 / / ( 1 1 1 ) SrTi O 3 ) , while the 2D layer is perpendicular to the SrTiO3 (1 1 0) substrate ( ( 1 1 0 ) LiCo O 2 / / ( 1 1 0 ) SrTi O 3 ) . The anisotropic properties were confirmed by electrochemical measurements. Ex situ X-ray reflectivity measurements indicated that the impurity layer existed on the as-grown LiCoO2 was dissolved and a new SEI layer with lower density was formed after soaking into the electrolyte. In situ X-ray reflectivity measurements indicated that the surface roughness of the intercalation (1 1 0) Plane increased with applying voltages, while no significant changes in surface morphology were observed for the intercalation non-active (0 0 3) Plane during the pristine stage of the charge–discharge process.
Su Chen - One of the best experts on this subject based on the ideXlab platform.
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spherical colloidal photonic crystals with selected Lattice Plane exposure and enhanced color saturation for dynamic optical displays
ACS Applied Materials & Interfaces, 2019Co-Authors: Jing Zhang, Zhijun Meng, Ji Liu, Su ChenAbstract:While structural color materials have nonfading properties and contribute significantly to the sustainable development of pigments or dyes, they are plagued by low color saturation and limited color tunability. Here, we describe a new type of spherical colloidal photonic crystals (CPCs) prepared by a droplet-based microfluidic strategy, featuring enhanced color saturation and tunable structural colors. Methyl viologen (MV) functionalized SiO2 colloids were synthesized and used for the preparation of CPCs in microdroplets. Because of the absorption of incoherently scattered light by MV, the ratio of peak-to-background amplitude in the reflectance spectra of CPCs is increased, leading to brilliant structural color with enhanced saturation. The Lattice Plane exposure of spherical CPCs depends on the refractive index contrast between the filling medium and SiO2 building blocks, and this offers an alternative way to tune the structural color in a spherical CPC. Accordingly, a dynamic optical display was constructed, providing valuable insights to the future development of structural color-based sensors, surface coatings, or displays.
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spherical colloidal photonic crystals with selected Lattice Plane exposure and enhanced color saturation for dynamic optical displays
ACS Applied Materials & Interfaces, 2019Co-Authors: Jing Zhang, Zhijun Meng, Ji Liu, Su ChenAbstract:While structural color materials have nonfading properties and contribute significantly to the sustainable development of pigments or dyes, they are plagued by low color saturation and limited colo...
Yo Tomota - One of the best experts on this subject based on the ideXlab platform.
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in situ neutron diffraction of heavily drawn steel wires with ultra high strength under tensile loading
Acta Materialia, 2005Co-Authors: Yo Tomota, Tetsuya Suzuki, Atsushi Moriai, Nobuaki Minakawa, A Kanie, Yoshinori Shiota, Yukio MoriiAbstract:To make clear the strengthening mechanism of heavily drawn steel wires exhibiting ultra-high strength, in situ neutron diffraction during tensile loading was performed. A ferrite steel (FK) subjected to a true strain of 6.6 and a pearlite steel (PS) subjected to 4.0 were extended on a tensile tester and (1 1 0) diffraction profiles were measured at various holding stresses. Tensile strengths of steel FK and PS are 1.7 and 3.7 GPa, respectively. The change in (1 1 0) spacing with tensile stress is reversible, i.e., elastic, close to the relevant tensile strength. A stress versus (1 1 0) Lattice Plane strain is linear for steel FK while evidently nonlinear at higher stresses for steel PS. In steel PS in which cementite peaks were hardly observed, the strengthening mechanism is postulated to be different from that for as-patented pearlite steels.
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a neutron diffraction study on work hardening mechanism for a pearlite steel
Journal of The Society of Materials Science Japan, 2004Co-Authors: Atsuomi Kanie, Yo Tomota, Tetsuya Suzuki, S Torii, Atsushi Moriai, Nobuaki Minakawa, Yukio Morii, Takashi KamiyamaAbstract:The work hardening and the internal stress averaged in each constituent, so called “phase stress” in a pearlite steel were studied by means of neutron diffraction techniques, time-of-flight (TOF) and angler dispersion (AD) methods. The overall diffraction profiles obtained by the TOF method indicates that the cementite (122) and feirrite (110) peaks are preferable to be employed for the in situ neutron diffraction with the AD method during tensile testing. The stress partitioning between cementite and ferrite after the onset of plastic deformation is evidently found. Hence, the high work-hardening of the pearlite structure is demonstrated to be caused by the generation of phase stress. The influence of ferrite block orientation on the residual phase stress after tensile deformation is shown. Then, the heterogeneous plastic flow at several classes is speculated, which makes complicate to estimate the stress in each constituent from (hkl) Lattice Plane strains measured.
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in situ neutron diffraction study of if and ultra low carbon steels upon tensile deformation
Acta Materialia, 2003Co-Authors: Yo Tomota, P Lukas, Stefanus Harjo, J H Park, Noriyuki Tsuchida, D NeovAbstract:Abstract Tensile behavior of an interstitial-free (IF) and an ultra low-carbon (ULC) steel bearing similar concentrations of carbon and nitrogen was studied by means of an in situ neutron diffraction technique. The (110), (200) and (211) Lattice Plane strains were determined as a function of the applied stress, revealing three deformation stages; (1) elastic deformation, (2) grain to grain yielding and (3) the stage III deformation. The microstrain associated with dislocation density (ρ) was increased with tensile straining and the increasing rate was higher in the ULC steel than in the IF steel, resulting in higher flow stress in the ULC steel due to dynamic strain aging. The estimated ρ was summarized as a function of strain (e); ρ = ρ0 + AeB, leading to the description of flow stress (σ); σ=120+0.89μb A1/2eB/2 MPa, where ρ0, A and B were constants, μ shear modulus, and b the magnitude of Burgers vector. The above constants were influenced by dynamic strain aging through the Bailey–Hirsch relation.
Osami Sakata - One of the best experts on this subject based on the ideXlab platform.
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anisotropic mosaicity and Lattice Plane twisting of an m Plane gan homoepitaxial layer
CrystEngComm, 2019Co-Authors: Jaemyung Kim, Okkyun Seo, Yoshihiro Irokawa, Toshihide Nabatame, Yasuo Koide, Atsushi Tanaka, Jun Chen, Kenji Watanabe, Yoshio Katsuya, Osami SakataAbstract:We have observed anisotropic mosaicity of an m-Plane GaN homoepitaxial layer by X-ray diffraction topography imaging over a wafer and X-ray rocking curves measured at various wafer points. Crystal domains were well aligned along the [0001] directions, but showed higher mosaicity along the [20] direction. Images reconstructed from the full-width at half maximum showed stripe patterns along the [0001] direction. From the bending-angle images at two different azimuthal angles, we found that GaN (100) Planes were twisted along the [20] direction, which generated anisotropic features. High resolution X-ray rocking curves revealed the multi-domain structure of GaN (100) along the [20] direction. The evaluated bending-angle distribution of 0.030 ± 0.013° mainly originated from the epitaxial layer twisting. We propose two possible mechanisms for this anisotropic feature and the stripe patterns correlated with epitaxial layer twisting.
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Lattice Plane orientation mapping of homo epitaxial gan 0001 thin films via grazing incidence x ray diffraction topography in 2 in wafer
Applied Physics Express, 2018Co-Authors: Jaemyung Kim, Okkyun Seo, Chulho Song, Satoshi Hiroi, Yanna Chen, Yoshihiro Irokawa, Toshihide Nabatame, Yasuo Koide, Osami SakataAbstract:We propose a method for evaluating the Lattice-Plane orientation of homo-epitaxial GaN thin films using X-ray diffraction topography. The GaN diffraction peak and its rocking curve at every point in the wafer were recorded using an area detector. In addition, we describe the reconstruction method for the [0001] vector with qx , qy , and qz components of the physical surface of the sample using a matrix obtained from two equivalent diffraction topographic images. We obtained the qx , qy , and qz components of every point of the 2-in. wafer from images recorded at azimuthal angles of 0 and 120°.