414 results on '"Yogo, A."'
Search Results
2. Three-dimensional dose-distribution measurement of therapeutic carbon-ion beams using a ZnS scintillator sheet
- Author
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Ryo Horita, Katsunori Yogo, Hiromichi Ishiyama, Hikaru Souda, Seiichi Yamamoto, Masato Tsuneda, Tatsuaki Kanai, Kazushige Hayakawa, and Akihiko Matsumura
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Materials science ,Physics::Instrumentation and Detectors ,Health, Toxicology and Mutagenesis ,Sobp ,Linear energy transfer ,Heavy Ion Radiotherapy ,Bragg peak ,Sulfides ,Scintillator ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,Imaging, Three-Dimensional ,0302 clinical medicine ,Optics ,Ionization ,Linear Energy Transfer ,Radiology, Nuclear Medicine and imaging ,Fundamental Radiation Science ,Radiometry ,linear energy transfer (LET) ,Scintillation ,Radiation ,business.industry ,Water ,Dose-Response Relationship, Radiation ,Equipment Design ,silver-activated zinc sulfide (ZnS) ,3D dose distribution ,Zinc Compounds ,030220 oncology & carcinogenesis ,Ionization chamber ,AcademicSubjects/SCI00960 ,AcademicSubjects/MED00870 ,carbon-ion beam ,business ,Beam (structure) - Abstract
The accurate measurement of the 3D dose distribution of carbon-ion beams is essential for safe carbon-ion therapy. Although ionization chambers scanned in a water tank or air are conventionally used for this purpose, these measurement methods are time-consuming. We thus developed a rapid 3D dose-measurement tool that employs a silver-activated zinc sulfide (ZnS) scintillator with lower linear energy transfer (LET) dependence than gadolinium-based (Gd) scintillators; this tool enables the measurement of carbon-ion beams with small corrections. A ZnS scintillator sheet was placed vertical to the beam axis and installed in a shaded box. Scintillation images produced by incident carbon-ions were reflected with a mirror and captured with a charge-coupled device (CCD) camera. A 290 MeV/nucleon mono-energetic beam and spread-out Bragg peak (SOBP) carbon-ion passive beams were delivered at the Gunma University Heavy Ion Medical Center. A water tank was installed above the scintillator with the water level remotely adjusted to the measurement depth. Images were recorded at various water depths and stacked in the depth direction to create 3D scintillation images. Depth and lateral profiles were analyzed from the images. The ZnS-scintillator-measured depth profile agreed with the depth dose measured using an ionization chamber, outperforming the conventional Gd-based scintillator. Measurements were realized with smaller corrections for a carbon-ion beam with a higher LET than a proton. Lateral profiles at the entrance and the Bragg peak depths could be measured with this tool. The proposed method would make it possible to rapidly perform 3D dose-distribution measurements of carbon-ion beams with smaller quenching corrections.
- Published
- 2021
3. Jet Quenching Simulation with Consideration for Distribution of Heat Transfer Coefficient and Latent Heat for Martensitic Transformation under Rapid Cooling
- Author
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Takeuchi Hirohisa and Yasuhiro Yogo
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Materials science ,Distribution (number theory) ,Mechanics of Materials ,Mechanical Engineering ,Diffusionless transformation ,Latent heat ,Materials Chemistry ,Metals and Alloys ,Thermodynamics ,Heat transfer coefficient ,Jet quenching - Published
- 2021
4. Source position measurement by Cherenkov emission imaging from applicators for high‐dose‐rate brachytherapy
- Author
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Hiroyuki Okamoto, Kuniyasu Okudaira, Yumiko Noguchi, Hiroshi Oguchi, Hiroshi Yasuda, Hiromichi Ishiyama, Marika Nozawa, Katsunori Yogo, and Seiichi Yamamoto
- Subjects
Diagnostic Imaging ,Materials science ,medicine.medical_treatment ,Brachytherapy ,Uterine Cervical Neoplasms ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Optics ,Position (vector) ,medicine ,Humans ,Single image ,Cherenkov radiation ,Phantoms, Imaging ,business.industry ,Radiotherapy Planning, Computer-Assisted ,Device Camera ,Radiotherapy Dosage ,General Medicine ,High-Dose Rate Brachytherapy ,030220 oncology & carcinogenesis ,Female ,Light emission ,business - Abstract
Purpose We developed a novel and simple method to measure the source positions in applicators directly for high-dose-rate (HDR) brachytherapy based on Cherenkov emission imaging, and evaluated the performance. Methods The light emission from plastic applicators used in cervical cancer treatments, irradiated by an 192 Ir γ-ray source, was captured using a charge-coupled device camera. Moreover, we attached plastics of different shapes, including tapes, tubes, and plates to a metal applicator, to use as screens for the Cherenkov imaging. We determined the source positions and dwell intervals from the light profiles along with the applicator and compared these with preset values and dummy marker measurements. Results The source positions and dwell intervals measured from the light images were comparable to the dummy marker measurements and preset values. The distance from the applicator tip to the first source positions agreed with the dummy marker measurements within 0.2 mm for the plastic tandem. The dwell intervals measured using the Cherenkov method agreed with the preset values within 0.6 mm. The distances measured with three plastic types on the metal applicator also agreed with the dummy marker measurements within 0.2 mm. The dwell intervals measured using the plastic tape agreed with the preset values within 0.7 mm. Conclusions The proposed method should be suitable for rapid and easy quality assurance (QA) investigations in HDR brachytherapy, as it enables source position using a single image. The method allows for real-time, filmless measurements of the source positions to be obtained and is useful for rapid feedback in QA procedures.
- Published
- 2020
5. Effect of Counter Cations on the Hydrothermal Conversion of FAU-Type Zeolites into ABW or ANA and Their Potential Applicability for CO2/N2 Separation
- Author
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Katsunori Yogo and Junpei Fujiki
- Subjects
Materials science ,Chemical engineering ,General Chemical Engineering ,General Chemistry ,Hydrothermal circulation - Published
- 2020
6. Evaluation of Hot Forging Lubricants for Steel by Ring Compression Test with Rotating Die
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Michiaki Kamiyama, Noritoshi Iwata, Sawamura Masatoshi, and Yasuhiro Yogo
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business.product_category ,Materials science ,Mechanics of Materials ,Mechanical Engineering ,Die (manufacturing) ,Compression test ,General Materials Science ,Composite material ,Ring (chemistry) ,business ,Forging - Published
- 2020
7. Dosimetric calibration of GafChromic HD-V2, MD-V3, and EBT3 films for dose ranges up to 100 kGy
- Author
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S. R. Mirfayzi, King Fai Farley Law, M. Nakai, Alessio Morace, Akifumi Yogo, Yasunobu Arikawa, Shinsuke Fujioka, Yasuhiro Abe, and D. Golovin
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Scanner ,Materials science ,02 Physical Sciences ,Proton ,Cyclotron ,Analytical chemistry ,Radiation ,09 Engineering ,law.invention ,Wavelength ,law ,Calibration ,Irradiation ,Absorption (electromagnetic radiation) ,03 Chemical Sciences ,Instrumentation ,Applied Physics - Abstract
A dosimetric calibration of three types of radiochromic films (GafChromicTM HD-V2, MD-V3, and EBT3) was carried out for absorbed doses (D) ranging up to 100 kGy using a 130 TBq Co60 γ-ray source. The optical densities (ODs) of the irradiated films were acquired with the transmission-mode flatbed film scanner EPSON GT-X980. The calibration data were cross-checked using the 20-MeV proton beam from the azimuthally varying field cyclotron at the Research Center for Nuclear Physics in Osaka University. These experimental results not only present the measurable dose ranges of the films depending on the readout wavelength, but also show consistency with our hypothesis that the OD response curve [log(OD)–log(D) curve] is determined by the volumetric average of the absorption dose and does not strongly depend on the type of radiation for the excitation.
- Published
- 2021
8. Membrane Reactor for Methanol Synthesis Using Si-Rich LTA Zeolite Membrane
- Author
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Bo Liu, Shin-ichi Nakao, Hey Ryeon Lee, Yasuhiro Mogi, Yuichiro Yamaguchi, Masahiro Seshimo, Nobuyuki Shigaki, Hidetoshi Kita, and Katsunori Yogo
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methanol synthesis ,Materials science ,Filtration and Separation ,02 engineering and technology ,Permeance ,TP1-1185 ,010402 general chemistry ,01 natural sciences ,Chemical synthesis ,Article ,chemistry.chemical_compound ,Chemical engineering ,Chemical Engineering (miscellaneous) ,Hydrothermal synthesis ,zeolite membrane ,Zeolite ,Membrane reactor ,Process Chemistry and Technology ,Chemical technology ,membrane reactor ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Membrane ,chemistry ,Si-rich LTA ,TP155-156 ,Methanol ,0210 nano-technology ,Selectivity - Abstract
We successfully demonstrated the effect of a membrane reactor for methanol synthesis to improve one-pass CO2 conversion. An Si-rich LTA membrane for dehydration from a methanol synthesis reaction field was synthesized by the seed-assisted hydrothermal synthesis method. The H2O permselective performance of the membrane showed 1.5 × 10−6 mol m−2 s−1 Pa−1 as H2O permeance and around 2000 as selectivity of H2O/MeOH at 473 K. From the results of membrane reactor tests, the CO2 conversion of the membrane reactor was higher than that of the conventional packed-bed reactor under the all of experimental conditions. Especially, at 4 MPa of reaction pressure, the conversion using the membrane reactor was around 60%. In the case of using a packed-bed reactor, the conversion was 20% under the same conditions. In addition, the calculated and experimental conversion were in good agreement in both the case of the membrane reactor and packed-bed reactor.
- Published
- 2021
9. Estimation of the three-dimensional (3D) dose distribution of electron beams from medical linear accelerator (LINAC) using plastic scintillator plate
- Author
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Katsunori Yogo, Seiichi Yamamoto, Ryo Horita, Hiroshi Oguchi, Masataka Komori, Fumitaka Kawabata, Takayoshi Nakaya, Yoshiyuki Hirano, and Kuniyasu Okudaira
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010302 applied physics ,Scintillation ,Radiation ,Materials science ,Physics::Instrumentation and Detectors ,business.industry ,Electron ,Scintillator ,01 natural sciences ,Linear particle accelerator ,Imaging phantom ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Optics ,Ionization ,0103 physical sciences ,Cathode ray ,Charge-coupled device ,business ,Instrumentation - Abstract
Measurements of three-dimensional (3D) dose distribution of electron-beams in water are important for high-energy electron beams from medical linear accelerators (LINAC). Although ionization chambers are commonly used for this purpose, measurements take a long time for precise 3D dose distribution. To solve the problem, we tried the measurements of the 3D dose distributions using a scintillator plate combined with a mirror. After we placed a 1 mm thick plastic scintillator plate at the upper inside of a black box, a water phantom was set above the plastic scintillator plate outside the black box, and electron beam was irradiated to the water phantom from the upper side. The attenuated electron-beam by the water in the phantom was detected by the plastic scintillator plate and the scintillation image was formed in the plate. The image was reflected by a surface mirror set below the plastic scintillator plate and detected by a cooled charge coupled device (CCD) camera from the side. We changed the depths of the water in the phantom, obtained the scintillation images, and calculated a 3D scintillation image using the measured images. Measurements were made for 9 MeV and 12 MeV electron-beams using the imaging system. From the images, we could successfully form 3D scintillation images. The depth profiles measured from the 3D images showed almost identical distribution with those calculated by the planning system within the difference of 5%. The lateral profiles also showed almost identical within the difference of the widths less than 2.5 mm. We conclude that the proposed method is promising for 3D dose distribution measurements of electron-beams.
- Published
- 2019
10. An Induction Heating Analysis with Consideration of Temperature Dependent B-H Curves and Change in Phase Transformation under Rapid Heating
- Author
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Takeuchi Hirohisa and Yasuhiro Yogo
- Subjects
Materials science ,Induction heating ,Mechanics of Materials ,Mechanical Engineering ,Phase (matter) ,Materials Chemistry ,Metals and Alloys ,Thermodynamics ,Transformation (music) - Published
- 2019
11. CAE-based process design for improving formability in hot stamping with partial cooling
- Author
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Eiichi Ota, Noritoshi Iwata, Hidekazu Nishigaki, and Yasuhiro Yogo
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0209 industrial biotechnology ,Materials science ,Metals and Alloys ,Process design ,02 engineering and technology ,Hot stamping ,Deformation (meteorology) ,Flow stress ,Industrial and Manufacturing Engineering ,Finite element method ,Computer Science Applications ,Cracking ,020303 mechanical engineering & transports ,020901 industrial engineering & automation ,Forming limit diagram ,0203 mechanical engineering ,Modeling and Simulation ,Ceramics and Composites ,Formability ,Composite material - Abstract
A CAE-based process design method was developed to improve formability in hot stamping by controlling the temperature distribution during the forming step. Specifically, areas where deformation is not desired should be cooled to make them harder, and areas where deformation is desired should be kept at higher temperature. In this study, a tailored initial temperature distribution was calculated through three-step analysis of the deformation behavior by a thermo-mechanical forming simulation. First, the deformation severity was evaluated from the damage value for each finite element by using a forming limit diagram (FLD) at elevated temperature. The cautionary damage value was then defined to determine whether the element should be cooled. Finally, the tailored initial temperature was calculated based on the temperature-dependent flow stress. This procedure was applied to a high-rigidity pillar model that could not be formed by the conventional hot stamping process without cracking. The improved formability was confirmed experimentally. Thus, controlling the temperature distribution increases the diversity of shapes achievable by hot stamping.
- Published
- 2019
12. Synthesis of titania nanoparticle-dispersed hybrid membranes from allyloxytitanium and phosphonic acid derivatives for fuel cell
- Author
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Toshinobu Yogo, Koichiro Hayashi, Wataru Sakamoto, and Naoya Ozawa
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chemistry.chemical_classification ,Materials science ,Small-angle X-ray scattering ,Nanoparticle ,Filtration and Separation ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Methacrylate ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Amorphous solid ,Hydrolysis ,Membrane ,Chemical engineering ,chemistry ,General Materials Science ,Thermal stability ,Physical and Theoretical Chemistry ,0210 nano-technology - Abstract
Inorganic-organic hybrid membranes consisting of an aliphatic backbone and amorphous TiO2 nanoparticles (NPs) were synthesized from tetraallyloxytitanium and phosphonic acid methacrylate via a simple copolymerization-hydrolysis method. Tetraallyoxytitanium (TAT) was copolymerized with 2-hydroxyethyl methacrylate acid phosphate (HEMAP), and then hydrolyzed, yielding inorganic-organic hybrid composites. IR and 13C NMR spectroscopy confirmed the formation of the inorganic-organic hybrid structure. TEM and SAXS showed that amorphous TiO2 NPs were dispersed in the polymer matrix. The membranes exhibited good thermal stability up to 180 °C. The aliphatic chains of the methacrylate derivative dispersed with TiO2 NPs improved the mechanical properties of the membranes. The tensile modulus of the HEMAP/TAT membrane with a composition of 95:5 was 505 MPa. The conductivity of the 95:5 membranes was 4.1 × 10-2 S cm-1 at 130 °C and 100% relative humidity (RH), while it was 4.7 × 10-4 S cm-1 at 130 °C and 19.3% RH. The peak power of the 95:5 membrane was 4.8 mW/cm2 at 140 °C and 30% RH. The cell utilizing the hybrid membrane was operated at 140 °C and 30% RH for 72 h without any drop in cell voltage.
- Published
- 2018
13. Organic-Inorganic Hybrid Nanoparticles for Tracking the Same Cells Seamlessly at the Cellular, Tissue, and Whole Body Levels
- Author
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Yusuke Sato, Koichiro Hayashi, Toshinobu Yogo, Wataru Sakamoto, and Maruoka Hiroki
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0301 basic medicine ,Fluorescence-lifetime imaging microscopy ,Materials science ,Biomedical Engineering ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Porphyrin ,Regenerative medicine ,Fluorescence ,In vitro ,Biomaterials ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,chemistry ,In vivo ,Nanomedicine ,0210 nano-technology - Abstract
Techniques to elucidate the kinetics and distribution of the same cells in the whole body and in tissues are necessary for further studies of cancer, immunity, and regenerative medicine. Fluorescent imaging is a powerful technique for visualization of cells. However, current fluorescent probes are applicable in either the ultraviolet (UV)-visible (Vis) region (300-650 nm) or the biological transparency window (BTW, 650-900 nm), but not both. Thus, they cannot serve as fluorescent probes for both in vivo and in vitro imaging, and it is difficult to achieve imaging of the same cells seamlessly from the cellular level to the whole body and tissue levels using currently available fluorescent probes. Accordingly, in this paper, we describe organic-inorganic hybrid nanoparticles (HNPs) that could be used to achieve seamless tracking of the same cells. Within the HNPs, a porphyrin molecule, Vis-fluorophore, was surrounded by a siloxane chain, preventing the aggregation of porphyrin molecules. As a result, the porphyrin fluorescence was not quenched. Furthermore, indocyanine green (ICG), a BTW fluorophore, was localized on the HNP surface, leading to fluorescence resonance energy transfer (FRET) from porphyrin to ICG only near the HNP surface. Through the above structural design, the HNPs acquired both excitation (λ
- Published
- 2021
14. Theranostic Nanoparticles for MRI-Guided Thermochemotherapy: 'Tight' Clustering of Magnetic Nanoparticles Boosts Relaxivity and Heat-Generation Power
- Author
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Toshinobu Yogo, Wataru Sakamoto, Koichiro Hayashi, and Yoshitaka Sato
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Materials science ,Biocompatibility ,Theranostic nanoparticles ,Biomedical Engineering ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,Abdomen tumors ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Biomaterials ,Heat generation ,Drug delivery ,Magnetic nanoparticles ,0210 nano-technology ,Mri guided ,Biomedical engineering - Abstract
Magnetic-resonance-imaging (MRI)-guided magnetic thermochemotherapy is a potentially invasive technique combining diagnosis and treatment. It requires the development of multifunctional nanoparticles with (1) biocompatibility, (2) high relaxivity, (3) high heat-generation power, (4) controlled drug release, and (5) tumor targeting. Here, we show the synthesis of such multifunctional nanoparticles ("Core-Shells") and the feasibility of MRI-guided magnetic thermochemotherapy using the synthesized nanoparticles. "Tight" iron-oxide nanoparticle clustering to zero interparticle distance within the Core-Shells boosts the relaxivity and heat-generation power while maintaining biocompatibility. The initial Core-Shell drug release occurs in response to an alternating magnetic field (AMF) and continues gradually after removal of the AMF. Thus, a single Core-Shell dose realizes continuous chemotherapy over a period of days or weeks. The Core-Shells accumulate in abdomen tumors, facilitating MRI visualization. Subsequent AMF application induces heat generation and drug release within the tumors, inhibiting their growth. Core-Shell magnetic thermochemotherapy exhibits significantly higher therapeutic efficacy than both magnetic hyperthermia and chemotherapy alone. More importantly, there are minimal side effects. The findings of this study introduce new perspectives regarding the development of materials for MRI, magnetic hyperthermia, and drug delivery systems. Both conventional and novel iron-oxide-based materials may render theranostics (i.e., techniques fusing diagnosis and treatment) feasible.
- Published
- 2021
15. Fabrication of disk-shaped, deuterated resorcinol/formaldehyde foam target for laser–plasma experiments
- Author
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Kohei Yamanoi, D. Golovin, Akifumi Yogo, Yumi Kaneyasu, Keiji Nagai, Takahisa Jitsuno, Takayoshi Norimatsu, Marilou Cadatal-Raduban, and Satoshi Shokita
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Nuclear and High Energy Physics ,Fabrication ,Materials science ,Hydrogen ,Proton ,020209 energy ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Resorcinol ,Plasma ,Laser ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,010305 fluids & plasmas ,Electronic, Optical and Magnetic Materials ,law.invention ,chemistry.chemical_compound ,Nuclear Energy and Engineering ,chemistry ,Deuterium ,Polymerization ,law ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering - Abstract
Resorcinol/formaldehyde (RF) foam resin is an attractive material as a low-density target in high-power laser–plasma experiments because of its fine network structure, transparency in the visible region, and low-Z element (hydrogen, carbon, and oxygen) composition. In this study, we developed disk-shaped RF foam and deuterated RF foam targets with 40–200 μm thickness and approximately 100 mg/cm3 density having a network structure from 100 nm to a few micrometers cell size. By deuteration, the polymerization rate was drastically slowed down owing to kinetic isotope effects. These targets were used in high-power laser experiments where a megaelectronvolt proton beam was successfully generated.
- Published
- 2021
16. Super-strong magnetic field-dominated ion beam dynamics in focusing plasma devices.
- Author
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Morace, A., Abe, Y., Honrubia, J. J., Iwata, N., Arikawa, Y., Nakata, Y., Johzaki, T., Yogo, A., Sentoku, Y., Mima, K., Ma, T., Mariscal, D., Sakagami, H., Norimatsu, T., Tsubakimoto, K., Kawanaka, J., Tokita, S., Miyanaga, N., Shiraga, H., and Sakawa, Y.
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FOCUSED ion beams ,PARTICLE physics ,PLASMA devices ,PLASMA focus ,ION beams ,MATERIALS science - Abstract
High energy density physics is the field of physics dedicated to the study of matter and plasmas in extreme conditions of temperature, densities and pressures. It encompasses multiple disciplines such as material science, planetary science, laboratory and astrophysical plasma science. For the latter, high energy density states can be accompanied by extreme radiation environments and super-strong magnetic fields. The creation of high energy density states in the laboratory consists in concentrating/depositing large amounts of energy in a reduced mass, typically solid material sample or dense plasma, over a time shorter than the typical timescales of heat conduction and hydrodynamic expansion. Laser-generated, high current–density ion beams constitute an important tool for the creation of high energy density states in the laboratory. Focusing plasma devices, such as cone-targets are necessary in order to focus and direct these intense beams towards the heating sample or dense plasma, while protecting the proton generation foil from the harsh environments typical of an integrated high-power laser experiment. A full understanding of the ion beam dynamics in focusing devices is therefore necessary in order to properly design and interpret the numerous experiments in the field. In this work, we report a detailed investigation of large-scale, kilojoule-class laser-generated ion beam dynamics in focusing devices and we demonstrate that high-brilliance ion beams compress magnetic fields to amplitudes exceeding tens of kilo-Tesla, which in turn play a dominant role in the focusing process, resulting either in a worsening or enhancement of focusing capabilities depending on the target geometry. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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17. Second Harmonic Generation From Phase-Engineered Metasurfaces of Nanoprisms
- Author
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Hirofumi Yogo, Soon Hock Ng, Yoshiaki Nishijima, Kannta Mochizuki, Stefan Lundgaard, Mako Sugiura, Atsushi Sugita, Saulius Juodkazis, and Jingwen Hu
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Materials science ,lcsh:Mechanical engineering and machinery ,Phase (waves) ,Physics::Optics ,02 engineering and technology ,Substrate (electronics) ,010402 general chemistry ,01 natural sciences ,Article ,Condensed Matter::Materials Science ,lcsh:TJ1-1570 ,Electrical and Electronic Engineering ,finite difference time domain ,Plasmon ,second harmonic generation ,business.industry ,Mechanical Engineering ,Finite-difference time-domain method ,Second-harmonic generation ,Resonance ,021001 nanoscience & nanotechnology ,metasurfaces ,optics ,0104 chemical sciences ,phase control ,Wavelength ,Control and Systems Engineering ,Optoelectronics ,0210 nano-technology ,business ,Electron-beam lithography - Abstract
Metasurfaces of gold (Au) nanoparticles on a SiO2-Si substrate were fabricated for the enhancement of second harmonic generation (SHG) using electron beam lithography and lift-off. Triangular Au nanoprisms which are non-centro-symmetric and support second-order nonlinearity were examined for SHG. The thickness of the SiO2 spacer is shown to be an effective parameter to tune for maximising SHG. Electrical field enhancement at the fundamental wavelength was shown to define the SHG intensity. Numerical modeling of light enhancement was verified by experimental measurements of SHG and reflectivity spectra at the normal incidence. At the plasmonic resonance, SHG is enhanced up to &sim, 3.5 ×, 103 times for the optimised conditions.
- Published
- 2020
18. Imaging Cherenkov emission for quality assurance of high-dose-rate brachytherapy
- Author
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Hiromichi Ishiyama, Marika Nozawa, Yasushi Nagata, Akihiro Matsushita, Kazushige Hayakawa, Katsunori Yogo, Yuya Tatsuno, Seiko Hirota, Hiroshi Yasuda, Shuichi Ozawa, and Takahiro Shimo
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Materials science ,medicine.medical_treatment ,Astrophysics::High Energy Astrophysical Phenomena ,Monte Carlo method ,Brachytherapy ,Physics::Medical Physics ,Quantum physics ,lcsh:Medicine ,Radiation ,Article ,030218 nuclear medicine & medical imaging ,Techniques and instrumentation ,03 medical and health sciences ,0302 clinical medicine ,Optics ,medicine ,lcsh:Science ,Image resolution ,Cherenkov radiation ,Multidisciplinary ,business.industry ,lcsh:R ,High-Dose Rate Brachytherapy ,Applied physics ,Optics and photonics ,030220 oncology & carcinogenesis ,Light emission ,lcsh:Q ,business ,Quality assurance - Abstract
With advances in high-dose-rate (HDR) brachytherapy, the importance of quality assurance (QA) is increasing to ensure safe delivery of the treatment by measuring dose distribution and positioning the source with much closer intervals for highly active sources. However, conventional QA is time-consuming, involving the use of several different measurement tools. Here, we developed simple QA method for HDR brachytherapy based on the imaging of Cherenkov emission and evaluated its performance. Light emission from pure water irradiated by an 192Ir γ-ray source was captured using a charge-coupled device camera. Monte Carlo calculations showed that the observed light was primarily Cherenkov emissions produced by Compton-scattered electrons from the γ-rays. The uncorrected Cherenkov light distribution, which was 5% on average except near the source (within 7 mm from the centre), agreed with the dose distribution calculated using the treatment planning system. The accuracy was attributed to isotropic radiation and short-range Compton electrons. The source positional interval, as measured from the light images, was comparable to the expected intervals, yielding spatial resolution similar to that permitted by conventional film measurements. The method should be highly suitable for quick and easy QA investigations of HDR brachytherapy as it allows simultaneous measurements of dose distribution, source strength, and source position using a single image.
- Published
- 2020
19. Metamaterial Concentrator for Thermal Energy Harvester
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Adik Putra Andika, Haryo Wibowo, Rapha Nichita Kaikatui, Paulus Mangera, Damis Hardiantono, Yogo Adhi Nugroho, Vinsenius Letsoin, and Herry Susanto
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lcsh:GE1-350 ,0303 health sciences ,Materials science ,Thermoelectric cooling ,heat energy ,business.industry ,Electric potential energy ,thermal harvesting ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Concentrator ,Engineering physics ,Renewable energy ,03 medical and health sciences ,metamaterial thermal concentrator ,Thermoelectric effect ,Electricity ,0210 nano-technology ,business ,Thermal energy ,lcsh:Environmental sciences ,030304 developmental biology ,Voltage - Abstract
Energy demand increases in line with rapid technological advances. Research on the harvesting of renewable energy continues to be done to make efforts to convert heat energy, which is very abundant in our daily environment. Thermoelectric technology is an alternative source in answering energy needs and can produce energy on a large and small scale. Thermoelectric technology works by converting heat energy into electricity directly, or from electricity to cold. This research presents an experimental study conducted to find out the thermoelectric characteristics of the TEC in the reversal function, with heating and cooling tests on each side of the TEC type thermoelectric element, carried out to obtain the voltage value as the electrical potential generated from this element. The result is thermoelectric potential to generate DC electricity but is very limited in the function of maintaining a heat source on the hot side element. This research then proposes thermal metamaterial that functions as a collector of thermal energy in the method of converting thermal energy into DC electrical energy for the application of low power consumption communication systems.
- Published
- 2020
20. Pure silica CHA-type zeolite membranes for dry and humidified CO2/CH4 mixtures separation
- Author
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Koji Kida, Katsunori Yogo, and Yasushi Maeta
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Materials science ,Dry gas ,Filtration and Separation ,02 engineering and technology ,Permeance ,Permeation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,chemistry.chemical_compound ,Membrane ,Chemical engineering ,chemistry ,0210 nano-technology ,Selectivity ,Zeolite ,Water vapor ,Concentration polarization - Abstract
Dense and thin pure silica CHA-type zeolite (Si-CHA) membranes have been synthesized on porous α-alumina supports and investigated for CO2 permeation and CO2/CH4 separation performance under dry and humidified conditions. Si-CHA membranes with ultra-high permeance were greatly affected by performance suppression due to concentration polarization under high pressure and low feed-rate conditions. Under high feed-rate conditions at 298 K and a feed pressure of 0.1 MPaG, the CO2/CH4 selectivity was 130 with a CO2 permeance of 4.0 × 10–6 mol/(m2 s Pa) for an equimolar CO2/CH4 dry gas mixture. The presence of water vapor significantly reduced CO2 permeance, but the performance improved as feed pressure increased. The CO2/CH4 selectivities at high pressure with and without water vapor were essentially the same.
- Published
- 2018
21. Investigation of Hardness Change for Spot Welded Tailored Blank in Hot Stamping Using CCT and Deformation-CCT Diagrams
- Author
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Nozomi Kurato, Noritoshi Iwata, and Yasuhiro Yogo
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Materials science ,Metallurgy ,Metals and Alloys ,02 engineering and technology ,Hot stamping ,Welding ,Deformation (meteorology) ,Continuous cooling transformation ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,Blank ,law.invention ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Mechanics of Materials ,law ,Martensite ,0210 nano-technology ,Spot welding - Abstract
When an outer panel of a B-pillar is manufactured with the hot stamping process, reinforcements are spot welded on its inner side. Before reinforcements are added, the microstructure of the outer panel is martensite. However, reheating during spot welding changes the martensite to ferrite, which has a lower hardness in the heat-affected zone than in other areas. If spot welding is conducted before hot stamping for making a spot welded tailored blank, the microstructure in the spot welded tailored blank after hot stamping is martensite. This sequence of processes avoids hardness reduction due to spot welding. In this study, the hardness and microstructure around spot welded parts of the tailored blank were investigated. The results clearly showed that areas close to the spot welded parts are severely stretched during hot stamping. In addition, stretching suppresses the martensitic phase transformation and reduces the hardness. To characterize this phenomenon, a simulation was conducted that considered the effects of pre-strain on the phase transformation. A continuous cooling transformation (CCT) diagram and a deformation continuous cooling transformation (DCCT) diagram were made in order to quantify the effect of the cooling rate and pre-strain on the phase transformation and hardness. The hardness was then calculated using the experimentally measured CCT and DCCT diagrams and the finite element analysis results. The calculated hardness was compared with the experimental hardness. Good agreement was found between the calculated and experimental results.
- Published
- 2018
22. Facile preparation of surface-oxidized nanoporous Pd for homocoupling reaction
- Author
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Wei Zhang, Shin-ichi Yamaura, Toshinobu Yogo, Masatomo Hattori, and Wataru Sakamoto
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Materials science ,Chemical engineering ,Mechanics of Materials ,Nanoporous ,Mechanical Engineering ,General Materials Science ,Condensed Matter Physics ,Layer (electronics) ,Catalysis - Abstract
Surface-oxidized nanoporous Pd (SO NP Pd) catalyst was prepared easily from nanoporous Pd, which was dealloyed from a NiPdP glass. 1,3-Diynes were synthesized in high to excellent yields through the homocoupling of terminal acetylenes using SO NP Pd prepared at 250 °C in air. The presence of Pd (II) in the surface-oxidized layer was crucial for the homocoupling reaction of terminal alkynes.
- Published
- 2021
23. Cu-oleate microspheres fabricated by emulsion method as novel targets for fast ignition laser fusion experiments
- Author
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Akira Yao, Akifumi Yogo, Takayoshi Norimatsu, S. Lee, Hiroshi Sawada, Hideo Nagatomo, Shohei Sakata, Yuki Iwasa, Kohei Yamanoi, Kana Fujioka, and Shinsuke Fujioka
- Subjects
Fabrication ,Materials science ,Mechanical Engineering ,chemistry.chemical_element ,Implosion ,Nanotechnology ,01 natural sciences ,Copper ,010305 fluids & plasmas ,Colloid ,Nuclear Energy and Engineering ,Transition metal ,chemistry ,Chemical engineering ,0103 physical sciences ,Emulsion ,General Materials Science ,Area density ,010306 general physics ,Inertial confinement fusion ,Civil and Structural Engineering - Abstract
We report the successful fabrication of copper (II) oleate [Cu(C18H33O2)2, Cu-oleate] microspheres as novel targets for laser fusion. Cu-oleate microspheres were prepared using emulsion method with Cu-oleate dissolved in an organic solvent. The fabricated microspheres exhibit a uniform radius of around 103 μm and a good sphericity of 0.97. The microspheres also have high atomic copper (Cu) content of ∼10 wt%, and the Cu ions are homogeneously distributed along their radii. Although defects which are 1-μm deep can be observed on the microsphere surfaces, these defects do not cause any significant perturbation that affects the resulting areal density during implosion. With good morphology, Cu content, and target performance, the Cu-oleate microspheres fabricated by emulsion method can then be used as targets for fast ignition laser fusion experiments such as FIREX. The use of these targets enables the x-ray observation of the laser-induced fast electron energy transfer on the compressed core.
- Published
- 2017
24. Metallic glass separators for fuel cells at intermediate temperatures
- Author
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Masatomo Hattori, Wataru Sakamoto, Toshinobu Yogo, Masaya Takemoto, Wei Zhang, Shin-ichi Yamaura, and Koichiro Hayashi
- Subjects
Materials science ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,chemistry.chemical_compound ,Polymer chemistry ,General Materials Science ,Relative humidity ,chemistry.chemical_classification ,Acrylate ,Amorphous metal ,Mechanical Engineering ,Membrane electrode assembly ,food and beverages ,Polymer ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Membrane ,chemistry ,Chemical engineering ,Mechanics of Materials ,0210 nano-technology ,Carbon ,Derivative (chemistry) - Abstract
Inorganic-organic hybrid membranes comprising an aliphatic backbone polymer and a trisiloxane bond were synthesized from a trisiloxane derivative, phosphonic acid acrylate, and vinylbenzotriazole, and used to prepare membrane electrode assembly (MEA) sandwiched between metallic glass separators (MGSs). The prepared MEA exhibited a higher cell voltage than that comprising carbon separators at 140 °C and 30% relative humidity for 50 h.
- Published
- 2017
25. Tolerance levels of CT number to electron density table for photon beam in radiotherapy treatment planning system
- Author
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Yasushi Nagata, Hiroshige Nozaki, Yusuke Ochi, Kosaku Habara, Minoru Nakao, Daisuke Kawahara, Takeo Nakashima, Yoshiharu Morimoto, Fumika Hosono, Shuichi Ozawa, Akito Saito, Toru Yoshizaki, Kiyoshi Yamada, Masahiro Hayata, Kentaro Miki, and Katsunori Yogo
- Subjects
Electron density ,Materials science ,Adipose tissue ,Electrons ,quality assurance ,Table (information) ,Imaging phantom ,flattening‐filter‐free beam ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,tolerance level ,Neoplasms ,Calibration ,medicine ,Technical Note ,Humans ,Radiology, Nuclear Medicine and imaging ,electron density ,Instrumentation ,87.55.d ,Photons ,Radiation ,business.industry ,Phantoms, Imaging ,Radiotherapy Planning, Computer-Assisted ,Radiotherapy Dosage ,Radiotherapy treatment planning ,CT number ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,87.55.Qr ,Cortical bone ,Radiotherapy, Intensity-Modulated ,Technical Notes ,Particle Accelerators ,Nuclear medicine ,business ,Tomography, X-Ray Computed ,Beam (structure) ,Algorithms - Abstract
The accuracy of computed tomography number to electron density (CT‐ED) calibration is a key component for dose calculations in an inhomogeneous medium. In a previous work, it was shown that the tolerance levels of CT‐ED calibration became stricter with an increase in tissue thickness and decrease in the effective energy of a photon beam. For the last decade, a low effective energy photon beam (e.g., flattening‐filter‐free (FFF)) has been used in clinical sites. However, its tolerance level has not been established yet. We established a relative electron density (ED) tolerance level for each tissue type with an FFF beam. The tolerance levels were calculated using the tissue maximum ratio (TMR) and each corresponding maximum tissue thickness. To determine the relative ED tolerance level, TMR data from a Varian accelerator and the adult reference computational phantom data in the International Commission on Radiological Protection publication 110 (ICRP‐110 phantom) were used in this study. The 52 tissue components of the ICRP‐110 phantom were classified by mass density as five tissues groups including lung, adipose/muscle, cartilage/spongy‐bone, cortical bone, and tooth tissue. In addition, the relative ED tolerance level of each tissue group was calculated when the relative dose error to local dose reached 2%. The relative ED tolerances of a 6 MVFFF beam for lung, adipose/muscle, and cartilage/spongy‐bone were ±0.044, ±0.022, and ±0.044, respectively. The thicknesses of the cortical bone and tooth groups were too small to define the tolerance levels. Because the tolerance levels of CT‐ED calibration are stricter with a decrease in the effective energy of the photon beam, the tolerance levels are determined by the lowest effective energy in useable beams for radiotherapy treatment planning systems.
- Published
- 2017
26. Single shot radiography by a bright source of laser-driven thermal neutrons and x-rays
- Author
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Yuki Abe, Seyed Reza Mirfayzi, Yuki Hoonoki, Masato Kanasaki, D. Golovin, T. Mori, Shinsuke Fujioka, Keisuke Koga, Ryosuke Kodama, Yasunobu Arikawa, Zechen Lan, Takehito Hayakawa, Hiroaki Nishimura, Akifumi Yogo, Mitsuo Nakai, Kunioki Mima, Tianyun Wei, Yosuke Suzuki, and Satyabrata Kar
- Subjects
Laser Acceleration ,Letter ,Materials science ,business.industry ,Radiography ,Astrophysics::High Energy Astrophysical Phenomena ,Nuclear Theory ,Spotlights 2021 ,General Engineering ,Single shot ,Laser ,General Physics and Astronomy ,Neutron Source ,Neutron temperature ,law.invention ,Optics ,law ,Plasmas, applied atomic and molecular physics, and applied nuclear physics ,Neutron source ,business ,Nuclear Experiment - Abstract
Thermal neutron (∼25 meV) beam is a powerful tool for investigating the structure and properties of materials used in science and technology. A laser-driven neutron source generating 1010 neutrons within 1 ns duration is utilized to a single shot radiography with a dual beam of thermal neutrons and X-rays. As a proof of principle, we show the non-destructive inspection of hazardous substances (Cadmium) contained in a typical battery, when the cadmium anode thickness is evaluated from the transmittance of thermal neutrons. The fact that the neutron inspection above is performed with a single laser shot, i.e. with a single bunch of neutrons leads to a safer neutron source that is optically controlled on/off, and provides a novel tool for science and engineering.
- Published
- 2021
27. Synthesis of inorganic-organic hybrid membranes consisting of organotrisiloxane linkages and their fuel cell properties at intermediate temperatures
- Author
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Masaya Takemoto, Wataru Sakamoto, Shin-ichi Yamaura, Wei Zhang, Koichiro Hayashi, and Toshinobu Yogo
- Subjects
chemistry.chemical_classification ,Acrylate ,Materials science ,Polymers and Plastics ,Organic Chemistry ,Membrane electrode assembly ,02 engineering and technology ,Polymer ,Nuclear magnetic resonance spectroscopy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Methacrylate ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Membrane ,chemistry ,Polymer chemistry ,Materials Chemistry ,Copolymer ,0210 nano-technology ,Derivative (chemistry) - Abstract
Inorganic-organic hybrid membranes consisting of an aliphatic main-chain polymer and trisiloxane bond were synthesized using a simple, one-pot process from a trisiloxane derivative, phosphonic acid acrylate, and vinylbenzotriazole. 1,5-Divinyl-3-phenylpentamethyltrisiloxane (DPPMTS) was copolymerized with 2-hydroxyethyl methacrylate acid phosphate (HEMAP), and N -vinylbenzotriazole (VBT), yielding inorganic-organic hybrid composites. The formation of the inorganic-organic hybrid structure was confirmed by IR, 13 C, and 29 Si NMR spectroscopy. The membranes exhibited good thermal stabilities up to 200 °C. The aliphatic chains of the methacrylate derivative copolymerized with trisiloxane in the hybrid membranes improved the mechanical properties of the membranes. The tensile modulus of the VBT/HEMAP/DPPMTS membrane with a composition of 1:9:5 was 1.19 GPa. The conductivities of the 1:9:5 membranes were 5.3 × 10 −2 S cm −1 and 4.1 × 10 −4 S cm −1 at 100 and 19.3% relative humidity (RH), respectively, and 130 °C. The membrane electrode assembly (MEA) using the hybrid membrane exhibited a peak power of 7.8 mW cm −2 at 140 °C and 30% RH.
- Published
- 2017
28. Stress-strain curve measurements of aluminum alloy and carbon steel by unconstrained-type high-pressure torsion testing
- Author
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Yasuhiro Yogo, Noritoshi Iwata, Sawamura Masatoshi, and Nobuki Yukawa
- Subjects
Materials science ,business.product_category ,Carbon steel ,Alloy ,0211 other engineering and technologies ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,Condensed Matter::Materials Science ,Breakage ,Aluminium ,021105 building & construction ,lcsh:TA401-492 ,General Materials Science ,Composite material ,Stress concentration ,Mechanical Engineering ,Stress–strain curve ,Metallurgy ,Torsion (mechanics) ,021001 nanoscience & nanotechnology ,chemistry ,Mechanics of Materials ,engineering ,Die (manufacturing) ,lcsh:Materials of engineering and construction. Mechanics of materials ,0210 nano-technology ,business - Abstract
In measurements of stress-strain (SS) curves, it is difficult to achieve a large strain, i.e., 5 (500%), which is introduced in actual metal forming processes. Recently, a constrained-type high-pressure torsion test was applied and allowed measurement of the SS curve up to a strain of 10. However, the testing method cannot be used for steel specimens, because a compression pressure of over 3 GPa has to be applied to a specimen via the dies, which leads to brakeage of the dies due to the stress concentration. Therefore, an unconstrained-type high-pressure torsion was applied for measurement of the SS curves of carbon steel. With this method, the rotation angle of the upper die and torque curve could be measured without breakage of the dies. After development of the methodology to convert the rotation angle-torque curve to a SS curve, the SS curves of an aluminum alloy and carbon steel were measured. The validity of the measured SS curves was examined by comparing the SS curves measured by the compression test, the constrained and unconstrained-type high-pressure torsion test. It was also confirmed that the difference of the unconstrained-type high-pressure torsion test was less than 10% compared to the other methods. Keywords: Stress-strain curve, High-pressure torsion, Aluminum, Super large strain range, Aluminum alloy, Carbon steel
- Published
- 2017
29. Stress-strain curve of pure aluminum in a super large strain range with strain rate and temperature dependency
- Author
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Risa Harada, Yasuhiro Yogo, Noritoshi Iwata, Sawamura Masatoshi, Kosei Miyata, and Takashi Ishikawa
- Subjects
Work (thermodynamics) ,Materials science ,Strain (chemistry) ,Stress–strain curve ,02 engineering and technology ,General Medicine ,Strain rate ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,01 natural sciences ,010101 applied mathematics ,Stress (mechanics) ,Dynamic recrystallization ,0101 mathematics ,Composite material ,0210 nano-technology ,Softening - Abstract
Recently, a high pressure torsion testing method was developed to measure stress - strain curves in a super large strain range, e.g. over 10. In this paper, through improvement of the method to measure strain rate and temperature dependencies, SS curves of pure aluminum were successfully measured in a temperature range of 298 - 573 K (25 - 300 oC) and a strain rate range of 0.02 - 2.0 /s. Strain rate dependency was observed at a lower strain rate of a higher temperature (0.02 /s, 473 K (200 oC) ). Then, distinguished strain rate dependency was shown at 573 K (300 oC). Work softening behavior, which was caused by dynamic recrystallization, was also observed over a strain of 4 (400 %)
- Published
- 2017
30. High-temperature Magnetization Characteristics of Steels
- Author
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Yasuhiro Yogo, Takashi Ishikawa, Takeuchi Hirohisa, Tomonori Tajima, and Tsuyoshi Hattori
- Subjects
010302 applied physics ,Materials science ,Condensed matter physics ,Mechanical Engineering ,Metals and Alloys ,02 engineering and technology ,01 natural sciences ,020501 mining & metallurgy ,Magnetization ,0205 materials engineering ,Mechanics of Materials ,0103 physical sciences ,Materials Chemistry ,Curie temperature - Published
- 2017
31. One-Pot Synthesis of Dual Stimulus-Responsive Degradable Hollow Hybrid Nanoparticles for Image-Guided Trimodal Therapy
- Author
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Michihiro Nakamura, Koichiro Hayashi, Wataru Sakamoto, Toshinobu Yogo, and Takuma Maruhashi
- Subjects
Fluorescence-lifetime imaging microscopy ,Materials science ,Stimuli responsive ,medicine.medical_treatment ,One-pot synthesis ,Nanoparticle ,Nanotechnology ,Photodynamic therapy ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Biomaterials ,In vivo ,Electrochemistry ,medicine ,Doxorubicin ,technology, industry, and agriculture ,DUAL (cognitive architecture) ,Photothermal therapy ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Drug delivery ,Biophysics ,0210 nano-technology ,Drug carrier ,medicine.drug - Abstract
Exploiting exogenous and endogenous stimulus-responsive degradable nanoparticles as drug carriers can improve drug delivery systems (DDSs). The use of hollow nanoparticles may facilitate degradation, and combination of DDS with photodynamic therapy (PDT) and photothermal therapy (PTT) may enhance the anticancer effects of treatments. Here, a one-pot synthetic method is presented for an anticancer drug (doxorubicin [DOX]) and photosensitizer-containing hollow hybrid nanoparticles (HNPs) with a disulfide and siloxane framework formed in response to exogenous (light) and endogenous (intracellular glutathione [GSH]) stimuli. The hollow HNPs emit fluorescence within the near-infrared window and allow for the detection of tumors in vivo by fluorescence imaging. Furthermore, the disulfides within the HNP framework are cleaved by intracellular GSH, deforming the HNPs. Light irradiation facilitates penetration of GSH into the HNP framework and leads to the collapse of the HNPs. As a result, DOX is released from the hollow HNPs. Additionally, the hollow HNPs generate singlet oxygen (1O2) and heat in response to light; thus, fluorescence imaging of tumors combined with trimodal therapy consisting of DDS, PDT, and PTT is feasible, resulting in superior therapeutic efficacy. Thus, this method may have several applications in imaging and therapeutics in the future.
- Published
- 2016
32. Newly developed Laboratory-based Size exclusion chromatography Small-angle x-ray scattering System (La-SSS)
- Author
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Rintaro Inoue, Saeko Yanaka, Tatsuo Nakagawa, Aya Okuda, Koichi Kato, Rina Yogo, Nobuhiro Sato, Masaaki Sugiyama, Maho Yagi-Utsumi, Kazuki Ito, Kazuki Omoto, Reiko Urade, and Ken Morishima
- Subjects
0301 basic medicine ,Materials science ,Size-exclusion chromatography ,lcsh:Medicine ,Characterization and analytical techniques ,Article ,law.invention ,03 medical and health sciences ,0302 clinical medicine ,Optics ,Data acquisition ,law ,lcsh:Science ,chemistry.chemical_classification ,Nanoscale biophysics ,Multidisciplinary ,Small-angle X-ray scattering ,business.industry ,Scattering ,Biomolecule ,lcsh:R ,Synchrotron ,Volumetric flow rate ,030104 developmental biology ,chemistry ,lcsh:Q ,business ,030217 neurology & neurosurgery ,Beam (structure) - Abstract
To understand a biological system, it is important to observe structures of biomolecules in the solution where the system is functionalized. Small-Angle X-ray Scattering coupled with Size Exclusion Chromatography (SEC-SAXS) is one of techniques to selectively observe the target molecules in the multi-component system. However, this technique is believed to be available only with a synchrotron-based SAXS instrument due to requirement of high beam intensity and, therefore, the limitation of the beam time was obstacle to satisfy demands from many bio-researchers. We newly developed Laboratory-based Size exclusion chromatography SAXS System (La-SSS) by utilizing a latest laboratory-based SAXS instrument and finely optimization of the balance between flow rate, cell volume, irradiation time and so on. La-SSS succeeded not only decoupling of target protein(s) from non-specific aggregates but also measurement of each concerned component in a multi-component system. In addition, an option: “stopping mode”, which is designed for improving statistics of SAXS profile, realized a high S/N data acquisition for the most interesting protein in a multi-component system. Furthermore, by utilizing a column having small bed volume, the small-scale SEC-SAXS study makes available. Through optimization of instrumental parameters and environments, La-SSS is highly applicable for experimental requirements from various biological samples. It is strongly expected that a La-SSS concept must be a normal option for laboratory-based SAXS in the near future.
- Published
- 2019
33. Advanced CO2 Capture Technologies
- Author
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Hidetaka Yamada, Shin-ichi Nakao, Katsunori Yogo, Kazuya Goto, and Teruhiko Kai
- Subjects
Adsorption ,Membrane ,Materials science ,Chemical engineering ,Air capture ,Absorption (chemistry) ,Membrane technology - Abstract
Introduction.- Chemistry of CO2 Capture.- CO2 Capture with Absorbents.- CO2 Capture with Absorbents.- Membrane for CO2 Separation.- Direct Air Capture.
- Published
- 2019
34. Hybrid Membrane-Type Fuel Cells for Intermediate Temperatures
- Author
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Toshinobu Yogo
- Subjects
Thermogravimetry ,Hydrolysis ,Vinylphosphonic acid ,chemistry.chemical_compound ,Membrane ,Materials science ,chemistry ,Chemical engineering ,Membrane electrode assembly ,Copolymer ,Infrared spectroscopy ,Conductivity - Abstract
This chapter describes the syntheses and characterization of proton-conductive hybrid membranes for the use at intermediate temperatures from 100 to 150 °C. The inorganic–organic hybrid membranes were synthesized from an unsaturated organoalkoxysilane and a vinylphosphonic acid derivative via copolymerization and acidic hydrolysis. The hybrid membranes were characterized by infrared spectroscopy, thermogravimetry, and indentation test. The proton conductivity was measured for various compositions of the membranes. The current–voltage curves for the membrane electrode assembly consisting of the hybrid membrane were evaluated.
- Published
- 2019
35. Advanced Post-Combustion Co2 Capture System Using Novel Polyamine-Based Solid Sorbents
- Author
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Katsuhiro Yoshizawa, Kazuya Goto, Nobuyuki Takayama, Ryohei Numaguchi, Shohei Nishibe, Hidetaka Yamada, Katsunori Yogo, Firoz Alam Chowdhury, Takeshi Okumura, Junpei Fujiki, and Shin Yamamoto
- Subjects
chemistry.chemical_compound ,Materials science ,chemistry ,Chemical engineering ,Post combustion ,Polyamine - Published
- 2019
36. Membrane for CO2 Separation
- Author
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Kazuya Goto, Shin-ichi Nakao, Hidetaka Yamada, Katsunori Yogo, and Teruhiko Kai
- Subjects
Flue gas ,Materials science ,Facilitated diffusion ,Combined cycle ,business.industry ,law.invention ,Membrane technology ,Membrane ,Chemical engineering ,law ,Natural gas ,Integrated gasification combined cycle ,Coal gasification ,business - Abstract
Among various CO2-capture technologies, membrane separation is considered as one of the promising solutions, because of its energy efficiency and operation simplicity. Many research and development are conducted for the (1) CO2/N2 (post-combustion: CO2 separation from flue gas), (2) CO2/CH4 (CO2 separation from natural gas), and (3) CO2/H2 (pre-combustion: CO2 separation from integrated gasification combined cycle (IGCC) processes). In this chapter, research and development of various types of membranes (polymeric membranes, inorganic membranes, ionic liquid membranes, and facilitated transport membranes) for these applications are briefly reviewed. In the latter part of the chapter, the development of “molecular gate” membrane modules by the authors for the pre-combustion to separate CO2 from H2 at the integrated coal gasification combined cycle (IGCC) power plants are reviewed.
- Published
- 2019
37. Peta-Pascal Pressure Driven by Fast Isochoric Heating with Multi-Picosecond Intense Laser Pulse
- Author
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Hiroyuki Shiraga, Shohei Sakata, King Fai Farley Law, Sadaoki Kojima, Mitsuo Nakai, Kunioki Mima, Yoshiki Nakata, Takayoshi Sano, Yuki Abe, Atsushi Sunahara, Kohei Yamanoi, Yugo Ochiai, Seung Ho Lee, Shinsuke Fujioka, Yuki Iwasa, Tetsuo Ozaki, Takayoshi Norimatsu, Yasunobu Arikawa, Hiroshi Sawada, Yasuhiko Sentoku, Tomoyuki Johzaki, Masayasu Hata, Shigeki Tokita, Naoki Higashi, Natsumi Iwata, Hiroki Morita, Alessio Morace, Akifumi Yogo, Ryosuke Kodama, Hiroshi Azechi, Hideo Nagatomo, Hitoshi Sakagami, Kazuki Matsuo, and Junji Kawanaka
- Subjects
Materials science ,Isochoric process ,General Physics and Astronomy ,Implosion ,FOS: Physical sciences ,Plasma ,Electron ,Laser ,7. Clean energy ,01 natural sciences ,Physics - Plasma Physics ,3. Good health ,law.invention ,Pulse (physics) ,Magnetic field ,Plasma Physics (physics.plasm-ph) ,Physics::Plasma Physics ,law ,Physics::Space Physics ,0103 physical sciences ,Atomic physics ,010306 general physics ,Intensity (heat transfer) - Abstract
Fast isochoric laser heating is a scheme to heat a matter with relativistic-intensity ($>$ 10$^{18}$ W/cm$^2$) laser pulse or X-ray free electron laser pulse. The fast isochoric laser heating has been studied for creating efficiently ultra-high-energy-density (UHED) state. We demonstrate an fast isochoric heating of an imploded dense plasma using a multi-picosecond kJ-class petawatt laser with an assistance of externally applied kilo-tesla magnetic fields for guiding fast electrons to the dense plasma.The UHED state with 2.2 Peta-Pascal is achieved experimentally with 4.6 kJ of total laser energy that is one order of magnitude lower than the energy used in the conventional implosion scheme. A two-dimensional particle-in-cell simulation reveals that diffusive heating from a laser-plasma interaction zone to the dense plasma plays an essential role to the efficient creation of the UHED state., 8 pages, 4 figures, 1 table
- Published
- 2019
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38. Powder and Thin Film Synthesis
- Author
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Toshinobu Yogo
- Subjects
Materials science ,Precipitation (chemistry) ,Alkaline hydrolysis (body disposal) ,law.invention ,chemistry.chemical_compound ,Hydrolysis ,chemistry ,Chemical engineering ,law ,visual_art ,Alkoxide ,visual_art.visual_art_medium ,Ceramic ,Crystallization ,Thin film ,Stoichiometry - Abstract
Ceramic powders are synthesized using chemical solution methods, such as organic acid salt, precipitant generation, alkaline hydrolysis, and alkoxide hydrolysis. The powder synthesis by precipitation and hydrolysis and the synthesis of monodispersed particles are described. The formation of complex alkoxide of lithium niobate (LN) precursor is confirmed by 93Nb nuclear magnetic resonance spectroscopy. Stoichiometric LN films are synthesized on various substrates via chemical solution route. The synthesis of the designed precursor in solution is a key for the low-temperature crystallization of high-quality LN films with preferred orientation. Several functional ceramic thin films of multicomponent oxides are also synthesized using chemical solution process.
- Published
- 2019
39. Current and Future Nanostructured Metals
- Author
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Toshinobu Yogo
- Subjects
symbols.namesake ,Materials science ,Nanoporous ,symbols ,Nanotechnology ,Electrochemical etching ,Current (fluid) ,Heterogeneous catalysis ,Plasmon ,Raman scattering ,Catalysis - Abstract
Nanoporous metals (NPMs) consist of an interconnected backbone and nanosized pores. NPMs were prepared from parent alloys by chemical and electrochemical etching. The interconnected ligaments and nanostructured pores of NPMs are the origins of their novel properties. NP Au and NP Pd exhibited remarkable catalytic reactions compared with nanoparticle-based and supported catalysts. NP Au showed prominent optical properties in plasmonics and surface-enhanced Raman scattering (SERS).
- Published
- 2019
40. CO2 Capture with Adsorbents
- Author
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Katsunori Yogo, Hidetaka Yamada, Teruhiko Kai, Kazuya Goto, and Shin-ichi Nakao
- Subjects
Adsorption ,Materials science ,Chemical engineering ,Adsorption method ,Amine gas treating ,Absorption (chemistry) ,Porous medium - Abstract
The adsorption method for CO2 capture is described in this chapter. The several types of absorbents including amine-based adsorbent and other ones are reviewed. Then, the advanced absorbents, i.e., “solid sorbents” developed in a project in RITE are described. The solid sorbents are composed of amine absorbents for chemical absorption and porous materials. They have similar CO2-adsorption characters with liquid amine absorbents. Furthermore, they make it possible to significantly reduce the energy consumed as sensible heat and evaporative latent heat in the regeneration process. Novel amines synthesized in this project have been employed for their developed solid sorbents to successfully fabricate innovative, high-performance solid sorbents capable of low-temperature regeneration with high-adsorption capacities. Using the novel amines obtained by the improved-synthesis method for a large scale, the moving-bed bench-scale plant test was recently started.
- Published
- 2019
41. Synthesis of pure silica STT-type zeolite membrane
- Author
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Koji Kida, Katsunori Yogo, and Yasushi Maeta
- Subjects
Materials science ,Hydrogen ,Mechanical Engineering ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,Permeance ,Permeation ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Toluene ,0104 chemical sciences ,chemistry.chemical_compound ,Membrane ,chemistry ,Mechanics of Materials ,General Materials Science ,0210 nano-technology ,Zeolite ,Porosity ,Selectivity - Abstract
STT-type pure silica zeolite (Si-STT) membrane is prepared on an α–alumina porous support tube and the gas permeation properties of the Si-STT membrane are investigated. The H 2 permeance of the Si-STT membrane increases at high temperatures. A high permeance and H 2 selectivity are achieved for the H 2 /toluene separation tests because the Si-STT membrane has an optimal pore size that does not block the permeation of hydrogen.
- Published
- 2017
42. A large-aperture high-sensitivity avalanche image intensifier panel
- Author
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R. Mizutani, Akifumi Yogo, Alessio Morace, Jo Nishibata, Hiroaki Nishimura, Mitsuo Nakai, S. Sakata, Yasunobu Arikawa, Hiroyuki Shiraga, Shinsuke Fujioka, S. Matsubara, R. Kodama, Yuki Abe, and Hidetaka Kishimoto
- Subjects
Scintillation ,Materials science ,Physics::Instrumentation and Detectors ,business.industry ,Image intensifier ,Avalanche photodiode ,01 natural sciences ,010305 fluids & plasmas ,law.invention ,Flash (photography) ,Optics ,law ,Night vision ,0103 physical sciences ,Quantum efficiency ,010306 general physics ,business ,Instrumentation ,Sensitivity (electronics) ,Image resolution - Abstract
A large-aperture high-sensitivity image intensifier panel that consists of an avalanche photodiode array and a light-emitting diode array is presented. The device has 40% quantum efficiency, over 104 optical gain, and 80-ns time resolution. The aperture size of the device is 20 cm, and with the current manufacturing process, it can be scaled to arbitrarily larger sizes. The device can intensify the light from a single particle scintillation emission to an eye-visible bright flash. The image resolution of the device is currently limited by the size of the avalanche photodiode that is 2 mm, although it can be scaled to smaller sizes in the near future. The image intensifier is operated at a small voltage, typically +57 V. The device can be applied to various applications, such as scintillation imaging, night vision cameras, and an image converter from non-visible light (such as infrared or ultraviolet) to visible light.
- Published
- 2018
43. Calibration of imaging plates sensitivity to high energy photons and ions for laser-plasma interaction sources
- Author
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S. R. Mirfayzi, Zechen Lan, Yasuhiro Abe, Alessio Morace, Tatiana Pikuz, Yasunobu Arikawa, D. Golovin, S. Shokita, and Akifumi Yogo
- Subjects
Materials science ,business.industry ,Plasma ,Laser ,law.invention ,Ion ,Optics ,High energy photon ,law ,Calibration ,Sensitivity (control systems) ,business ,Instrumentation ,Mathematical Physics - Published
- 2021
44. Investigation of plasma states formed under the interaction of high-power laser pulses with wire-shape Al–Cu target
- Author
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D. Golovin, M. A. Alkhimova, A. Ya. Faenov, Hiroaki Nishimura, S. Shokita, Yuki Honoki, Yasuhiro Abe, I. Yu. Skobelev, Tatiana Pikuz, Seung Ho Lee, Keisuke Koga, Yasunobu Arikawa, Akifumi Yogo, S. A. Pikuz, Shinsuke Fujioka, Kazuki Matsuo, and Kiyoko Okamoto
- Subjects
History ,Materials science ,business.industry ,law ,Optoelectronics ,Plasma ,business ,Laser ,Computer Science Applications ,Education ,Power (physics) ,law.invention - Abstract
Study of warm dense matter remains a very important task for understanding of many unique phenomena observing as in astrophysical research as in inertial fusion and fast ignition. In this work, we studied the parameters of plasma created by 1.7 ps laser pulses of relativistic intensity of 7 × 1018W/cm2in a specially designed Al–Cu wire-shape target, in comparison with a flat Cu and Al foil targets. We observed the strong emission of neutral or virtually neutral CuKαline from both Cu foil and Cu wire part of targets, which indicates the creation of a dense state exposed to the intense flow of hot electrons. Parameters of the plasma were evaluated by comparison of experimental spectra with the results of modeling by collisional-radiative kinetic code PrismSpec under the plasma zone approach. The using of Al foil in front of Cu wire part of target allowed avoiding the direct heating of Cu-wire and acquiring spectra of Cu K-shell emission evidently belonging to emission of warm dense matter (WDM) state. The upper estimate for the electron temperature in WDM region was found to be below 80 eV.
- Published
- 2021
45. Polarization-resolved femtosecond pump-probe spectroscopy for Au nanodisks at the LSP resonance
- Author
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Atsushi Sugita, Shohei Hamada, Hirofumi Yogo, Masayuki Yoshizawa, Atsushi Ono, Hiroumi Matsui, Yoshimasa Kawata, Kannta Mochizuki, and Wataru Inami
- Subjects
Materials science ,Physics::Optics ,Electron ,Dichroism ,Polarization (waves) ,Molecular physics ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Electric field ,Femtosecond ,Electrical and Electronic Engineering ,Spectroscopy ,Ultrashort pulse ,Electron-beam lithography - Abstract
The formation and relaxation of plasmon-induced hot electrons in Au nanodisks (AuNDs) with relatively large particle size was studied by femtosecond pump-probe spectroscopy. We temporally resolved the plasmon-induced formation of nonthermal electrons through intraband transitions and subsequent redistribution of nonthermal electrons to thermal electrons. The transient extinction spectra were found to exhibit clear dichroism for the pump polarization on a time scale of a few hundred femtoseconds. The electric field distribution was calculated using the Finite-difference time-domain (FDTD) method to be inhomogeneous inside the AuNDs under irradiation by linearly polarized light. The formation and relaxation of hot electrons occur locally inside the AuNDs, which results in the observed ultrafast dichroic response.
- Published
- 2020
46. Fatigue strength of Co–Cr–Mo alloy clasps prepared by selective laser melting
- Author
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Maki Ashida, Takayuki Nakamoto, Naoyuki Nomura, Noriyuki Wakabayashi, Hisashi Doi, Yoshiaki Yogo, Takao Hanawa, Atsushi Takaichi, Hidekazu Takahashi, Takahiro Kimura, and Yuka Kajima
- Subjects
Dental Stress Analysis ,Materials science ,Surface Properties ,Alloy ,Biomedical Engineering ,02 engineering and technology ,engineering.material ,Biomaterials ,03 medical and health sciences ,0302 clinical medicine ,Tensile Strength ,Materials Testing ,Ultimate tensile strength ,Surface roughness ,Selective laser melting ,Composite material ,Anisotropy ,Metallurgy ,030206 dentistry ,021001 nanoscience & nanotechnology ,Fatigue limit ,Dental Clasps ,Mechanics of Materials ,engineering ,Denture, Partial, Removable ,Chromium Alloys ,0210 nano-technology ,Dental Alloys ,Electron backscatter diffraction ,Removable partial denture - Abstract
We aimed to investigate the fatigue strength of Co-Cr-Mo clasps for removable partial dentures prepared by selective laser melting (SLM). The Co-Cr-Mo alloy specimens for tensile tests (dumbbell specimens) and fatigue tests (clasp specimens) were prepared by SLM with varying angles between the building and longitudinal directions (i.e., 0° (TL0, FL0), 45° (TL45, FL45), and 90° (TL90, FL90)). The clasp specimens were subjected to cyclic deformations of 0.25mm and 0.50mm for 10(6) cycles. The SLM specimens showed no obvious mechanical anisotropy in tensile tests and exhibited significantly higher yield strength and ultimate tensile strength than the cast specimens under all conditions. In contrast, a high degree of anisotropy in fatigue performance associated with the build orientation was found. For specimens under the 0.50mm deflection, FL90 exhibited significantly longer fatigue life (205,418 cycles) than the cast specimens (112,770 cycles). In contrast, the fatigue lives of FL0 (28,484 cycles) and FL45 (43,465 cycles) were significantly shorter. The surface roughnesses of FL0 and FL45 were considerably higher than those of the cast specimens, whereas there were no significant differences between FL90 and the cast specimens. Electron backscatter diffraction (EBSD) analysis indicated the grains of FL0 showed preferential close to001orientation of the γ phase along the normal direction to the fracture surface. In contrast, the FL45 and FL90 grains showed no significant preferential orientation. Fatigue strength may therefore be affected by a number of factors, including surface roughness and crystal orientation. The SLM process is a promising candidate for preparing tough removable partial denture frameworks, as long as the appropriate build direction is adopted.
- Published
- 2016
47. Examining the relationship between blood flow velocity and movement of erythrocytes in a capillary using laser doppler velocimetry
- Author
-
Tsunenobu Teranishi, Hiroki Ishida, Tsugunobu Andoh, Shunsuke Akiguchi, Yogo Takada, and Tadashi Hachiga
- Subjects
010302 applied physics ,010309 optics ,Materials science ,Capillary action ,0103 physical sciences ,Hemodynamics ,Blood flow ,Electrical and Electronic Engineering ,Laser Doppler velocimetry ,01 natural sciences ,Biomedical engineering - Published
- 2016
48. Smart Ferrofluid with Quick Gel Transformation in Tumors for MRI-Guided Local Magnetic Thermochemotherapy
- Author
-
Wataru Sakamoto, Toshinobu Yogo, and Koichiro Hayashi
- Subjects
Ferrofluid ,Materials science ,medicine.diagnostic_test ,Magnetic resonance imaging ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Biomaterials ,Nuclear magnetic resonance ,Transformation (function) ,Electrochemistry ,medicine ,0210 nano-technology ,Mri guided - Published
- 2016
49. Microstructure of Composite Derived by Oxidation of Amorphous Zr65Pd35 Alloy and the Interaction with Hydrogen
- Author
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Toshinobu Yogo, Masakuni Ozawa, and Shin'ichi Yamamura
- Subjects
Materials science ,Amorphous metal ,Hydrogen ,Mechanical Engineering ,Alloy ,Composite number ,Metallurgy ,Metals and Alloys ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Industrial and Manufacturing Engineering ,0104 chemical sciences ,Amorphous solid ,Catalysis ,Amorphous carbon ,chemistry ,Materials Chemistry ,engineering ,0210 nano-technology - Published
- 2016
50. One-pot synthesis of inorganic/organic hybrid membranes from organoalkoxysilane, hydroimidazole derivative, and cyclic sulfonic acid ester
- Author
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Koji Takahashi, Junji Umeda, Wataru Sakamoto, Toshinobu Yogo, and Koichiro Hayashi
- Subjects
Thermogravimetric analysis ,Materials science ,Mechanical Engineering ,Membrane electrode assembly ,One-pot synthesis ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,Membrane ,Chemical engineering ,chemistry ,Mechanics of Materials ,Nafion ,Siloxane ,Polymer chemistry ,General Materials Science ,Fourier transform infrared spectroscopy ,0210 nano-technology - Abstract
Inorganic/organic hybrid membranes for use in fuel cells were synthesized from 3-glycidoxypropyltrimethoxysilane (GPTMS), N-(3-triethoxysilylpropyl)-4,5-dihydroimidazole (NESPHI), and 1,3-propanesultone (PS) through a simple one-pot process. Fourier transform infrared spectroscopy and 13C nuclear magnetic resonance (NMR) measurements confirmed the sultone ring-opening reaction and formation of chemical bonds among the starting materials. The 29Si NMR measurements revealed that a siloxane network had formed within the hybrid membranes via the sol–gel process. The thermogravimetric analysis indicated that the synthesized membranes were thermally stable up to 170 °C. The conductivity of the membranes at low levels of relative humidity (RH) was improved by the addition of NESPHI. The best cell performance at intermediate temperatures and low RHs was achieved by the membrane electrode assembly using the NESPHI/GPTMS/PS = 1:3:4 hybrid membrane with a catalyst ink consisting of Nafion and the hybrid solution at a 1:1 ratio. At 120 °C and 53 % RH, the power density of the NESPHI/GPTMS/PS = 1:3:4 membrane was 6.6 mW/cm2.
- Published
- 2015
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