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Search Results: 1 - 10 of 2941 matches for " Akira Yamauchi "
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Ion Transport through Diffusion Layer Controlled by Charge Mosaic Membrane
Akira Yamauchi
International Journal of Chemical Engineering , 2012, DOI: 10.1155/2012/417179
Abstract: The kinetic transport behaviors in near interface of the membranes were studied using commercial anion and cation exchange membrane and charge mosaic membrane. Current-voltage curve gave the limiting current density that indicates the ceiling of conventional flux. From chronopotentiometry above the limiting current density, the transition time was estimated. The thickness of boundary layer was derived with conjunction with the conventional limiting current density and the transition time from steady state flux. On the other hand, the charge mosaic membrane was introduced in order to examine the ion transport on the membrane surface in detail. The concentration profile was discussed by the kinetic transport number with regard to the water dissociation (splitting) on the membrane surface. 1. Introduction It is well known that electrodialysis using ion exchange membrane makes drinking water or table salt from sea water.In Japan especially it is popular to use this electrodialysis in various fields such as food, medical pharmacy and ultrapure water [1–3]. However, the more efficient and improved electrodialysis have been required for pure water production because conventional system costs much of electric power at present. One of the main problems originates from the limiting current density that restricts the direct current for supplying through the system and depends on the thickness of diffusion layers. In this study, the way to see the thickness of the depleted solution layer was examined in order to improve the efficiency on the electrodialysis from fundamental standpoint. As mentioned above, the aim will be focused on the ionic behavior of ion transport from bulk solution to membrane surface. In addition, so far developed charge mosaic membrane [4–6] is introduced into electrodialysis model system and the ion transport mechanism is investigated. As experimental strategies, electrical methods were mainly adopted, and 4 kinds of membrane systems were selected to study: cation exchange membrane system (CMV), anion exchange membrane system (AMV), charge mosaic membrane and cation exchange membrane system (MM?+?CMV), and anion exchange membrane and charge mosaic membrane system (AMV?+?MM). The potentiometry was also used on the same membrane systems to elucidate the diffusion layer. The chronopotentiometry has been carried out to obtain the transition time [7–9]. The technique was adopted for 4 membrane arrangements to examine the contribution to the boundary layer of the charge mosaic membrane. The kinetic parameter about the boundary layer was noticed
Box/Peanut and Bar structures in edge-on and face-on SDSS nearby galaxies I. Catalogue
Akira Yoshino,Chisato Yamauchi
Physics , 2014, DOI: 10.1093/mnras/stu2249
Abstract: We investigate Box/Peanut and bar structures in image data of edge-on and face-on nearby galaxies taken from SDSS (Sloan Digital Sky Survey) to present catalogues containing the surface brightness parameters and the morphology classification. About 1700 edge-on galaxies and 2600 face-on galaxies are selected from SDSS DR7 in g, r and i-band. The images of each galaxy are fitted with the model of 2-dimensional surface brightness of S\'{e}rsic bulge and exponential disk. After removing some irregular data, Box/Peanut, bar and other structures are easily distinguished by eye using residual (observed minus model) images. We find 292 Box/Peanut structures in the 1329 edge-on samples and 630 bar structures in 1890 face-on samples in i-band, after removing some irregular data. Then the fraction of Box/Peanut galaxies is about 22 percent against the edge-on samples, and that of bar is about 33 percent (about 50 percent if 629 elliptical galaxies are removed) against the face-on samples. Furthermore the strengths of the Box/Peanut and bar are evaluated as "Strong", "Standard" and "Weak". We find that the strength increases slightly with increasing $B/T$ (Bulge-to-Total flux ratio), and that the fraction of Box/Peanut is generally about a half of that of bar irrespective of the strength and the $B/T$. Our result supports the idea that the Box/Peanut is bar seen edge-on.
Lumbar Disc Herniation with End-Plate Fracture and Secondary Ossification Mimicking an Epidural Tumor: A Case Report  [PDF]
Koun Yamauchi, Akira Hioki, Kazunari Fushimi, Katsuji Shimizu, Kei Miyamoto
Open Journal of Orthopedics (OJO) , 2013, DOI: 10.4236/ojo.2013.32020
Abstract:

We report a unique case of lumbar disc herniation, in particular, with end-plate and surrounded by extensive ossification, mimicking a tumor with calcification. A 69-year-old female suffered from right buttock and leg pain. Computed tomography (CT) showed an intracanalar mass with calcification or ossification, which most likely originated from the vertebral body at the L1/2 level epidural space. On a T1-weighted gadolinium magnetic resonance image, the capsule of the mass was enhanced and not only the content of the mass but also that of the L2 vertebral body were partially and slightly enhanced. The final pathological diagnosis was disc herniation with end-plate fracture and secondary ossification. A combination of these pathological conditions as accompanied by both end-plate fractures and extensive secondary ossifications has not been previously reported. This rare pathological condition needs to be recognized as a differential diagnosis.

Effect of Various Intensities of Drought Stress on δ13C Variation among Plant Organs in Rice: Comparison of Two Cultivars  [PDF]
Mana Kano-Nakata, Jiro Tatsumi, Yoshiaki Inukai, Shuichi Asanuma, Akira Yamauchi
American Journal of Plant Sciences (AJPS) , 2014, DOI: 10.4236/ajps.2014.511183
Abstract:

The δ13C value is widely used to assess the effects of drought on water status in plants. However, there is little information regarding the δ13C signature in different organs of rice. We conducted a field study to examine whether the δ13C among different plant parts would be affected by the intensities of drought, and to evaluate genotypic variation in δ13C fluctuation among plant parts affected by drought intensities. Two cultivars, “Nipponbare” (Oryzasativa ssp. japonica) and “Kasalath” (O. sativa ssp. indica), were grown in the field with a line-source sprinkler system. The δ13C values of panicles, flag leaves, straws, culms, and roots were measured from plant samples. The δ13C value increased as drought stress increased, especially in the panicles and roots. “Nipponbare” showed higher values of δ13C than “Kasalath” under the well-watered and mild drought stress conditions, but there was no significant difference between the genotypes in the δ13C value under the severe drought stress condition. The variation in δ13C value among different plant parts was also increased with increasing drought stress. In contrast, these variations were small under well-watered conditions. Furthermore, there was much greater

Simultaneous Application of Controlled Availability Fertilizers to Seeding Furrows with Seeding Increases Grain Yield and Quality of No-Till Cultivated Common Wheat in Japan  [PDF]
Toshio Tani, Motoki Hayashi, Kaku Hiraiwa, Ikumi Ochia, Shiro Mitsuya, Roel R. Suralta, Akira Yamauchi
Agricultural Sciences (AS) , 2015, DOI: 10.4236/as.2015.63028
Abstract: In Japan, common wheat is cultivated in upland fields converted from paddy fields, where poor drainage and high precipitation cause delay of sowing, lodging at the jointing stage, difficulty in topdressing at the ripening stage, and low yield. No-till cultivation has been promoted to overcome these problems but the yield is still low due to the lack of proper fertilizer application protocols. In this study, we determined whether an additional application of two kinds of Sigmoid coated urea as controlled availability fertilizers (CAFs) to the standard fertilization protocol for tillage cultivation can increase the yield and lodging resistance in no-till cultivated common wheat. Also, additional fertilization was applied to the seeding furrow simultaneously with seeding using a V-furrow no-till direct sowing (VFDS) machine. No-till cultivated plants had more tillers than tillage cultivated ones and consequently higher number of panicles and yield, caused by increased fertilizer application. The point-injected CAFs to the seeding furrow, which eluted at the jointing and ripening stages greatly increased the grain yield and protein content, respectively, compared to broadcast topdressing of ammonium sulfate at each stage. The simultaneous sowing and fertilization of additional CAFs using VFDS method in multi-year tests in farmers’ fields significantly increased the yield of no-till cultivated common wheat, and can be adopted by Japanese local farmers.
Bandstructure and Fermi Surfaces of CeRh3B2
Kunihiko Yamauchi,Akira Yanase,Hisatomo Harima
Physics , 2010, DOI: 10.1143/JPSJ.79.044717
Abstract: The electronic bandstructure and the Fermi surfaces of ferromagnetic CeRh3B2 are calculated by using FLAPW and LSDA+U method. As assuming several kinds of the ground state to describe the 4f electronic state, we propose a fully orbital- and spin-polarized state |lz=0, sx=1/2> as the ground state, instead of the conventional LS-coupled CEF ground state, generally expected in typical 4f compounds. This is supported by the fact that both the observed magnetic moment and the observed dHvA frequencies are well explained by the calculated electronic structure and the Fermi surfaces. The unconventional ground state is stabilized by the strong 4f-4f direct mixing between the neighbored Ce atoms along the extremely small distance along the c-axis in the hexagonal crystal cell.
The Synergistic Antibacterial Performance of a Cu/WO3-Added PTFE Particulate Superhydrophobic Composite Material  [PDF]
Kentaro Yamauchi, Tsuyoshi Ochiai, Goro Yamauchi
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2015, DOI: 10.4236/jbnb.2015.61001
Abstract: The synergistic antibacterial performance against Escherichia coli (E. coli), Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) of a Cu/WO3-added PTFE (polytetrafluoroethylene) particulate composite was reported in the previous paper. The origin of the synergistic antibacterial performance investigated by evaluating the photocatalytic decomposition of the Cu/WO3-added PTFE particulate composite material is reported in the present paper. Addition of Cu/WO3, visible-light-sensitive photocatalyst, to the PTFE particle dispersed superhydrophobic composite does not deteriorate the superhydrophobic property of the composite. Furthermore the existence of the polytetrafluoroethylene (PTFE) particles dispersed in the composite enhances the antibacterial property caused by the Cu/WO3. The authors call this “The synergistic effect”. In this study, a novel synergistic property of the Cu/WO3-added PTFE particulate composite was investigated by evaluating the degradation of gaseous acetaldehyde on the composite surface using visible light (10,000 lx) and UV-A (1 mW·cm-1) illumination. The 12 wt% Cu/WO3-8 wt% binder-80 wt% PTFE composite shows the synergistic visible-light-sensitive photocatalytic property. But 12 wt% Cu/WO3-44 wt% PTFE-44 wt% binder composite no longer shows the synergistic property of visible-light-sensitive photocatalytic property. The synergetic performance of visible-light-sensitive photocatalytic property appears only when PTFE concentration is larger than the critical point over which superhydrophobic property appears in accordance with the particulate composite model derived by the one of the authors. The hydrophobic surface leads to the low surface free energy derived by the revised Fowkes’s theory, which makes it difficult for bacteria to stick to the hydrophobic surface of the composite. Even if bacteria stick to the surface, they are decomposed by the visible-light-sensitive photocatalyst. This is the reason why the synergistic antibacterial performance against bacteria appears.
ZnO Heteroepitaxy on Sapphire Using a Novel Buffer Layer of Titanium Oxide: Crystallographic Behavior  [PDF]
Satoshi Yamauchi, Yoh Imai
Crystal Structure Theory and Applications (CSTA) , 2013, DOI: 10.4236/csta.2013.22006
Abstract: A novel buffer layer consists of titanium oxide grown on a-sapphire by low-pressure chemical vapor deposition using titanum-tetra-iso-propoxide and oxygen gas was used for ZnO epitaxial growth at temperature as low as 340 by plasma-assisted epitaxy using radio-frequency oxygen-gas plasma. XRD and RHEED indicated (0001)Ti2O3 layer in corundum crystal system was epitaxially grown on the substrate in an in-plane relationship of [1-100]Ti2O3// [0001]Al2O3 by uniaxial phase-lock system. Growth behavior of ZnO layer was significantly dependent on the Ti2O3 buffer-layer thickness, for example, dense columnar ZnO-grains were grown on the buffer layer thinner than 10 nm but the hexagonal pyramid-like grains were formed on the thin buffer layers below 2 nm. RHEED observations showed ZnO layer including the pyramid-like grains was epitaxially grown with single-domain on the thin buffer layer of 0.8 nm in the in-plane relationship of [1-100]ZnO//[1-100]Ti2O3//[0001]Al2O3, whereas the multi-domain was included in ZnO layer on the buffer layer above 10 nm.
Plasma-Assisted Chemical Vapor Deposition of TiO2 Thin Films for Highly Hydrophilic Performance  [PDF]
Satoshi Yamauchi, Yoh Imai
Crystal Structure Theory and Applications (CSTA) , 2013, DOI: 10.4236/csta.2013.21001
Abstract: Titanium-oxide layer was grown on glass substrate by plasma-assisted chemical vapor deposition (PCVD) using oxygen gas plasma excited by radio-frequency power at 13.56 MHz in the pressure as low as 3mtorr at relatively low temperature below 400oC, and studied on the crystallographic properties with the hydrophilic behavior comparing to the layer deposited by low-pressure chemical vapor deposition (LPCVD). Raman spectra indicated anatase-phase TiO2 layer without amorphous-phase could be formed above 340oC by simultaneous supply of plasma-cracked and non-cracked titanium-tetra-iso-propoxide (TTIP) used as preliminary precursor. Surface Scanning Electron Microscope images indicated the PCVD-layer consists of distinct nanometer-size plate-like columnar grains, in contrast to rugged micrometer-size grains in the LPCVD-layer. Extremely small water contact angle about 5o in dark and the quick conversion to super-hydrophilicity by UV-irradiation with a light-power density as low as 50 W/cm2 were observed on the PCVD- layer grown at 380oC, while the large initial contact angle was above 40o and the response for the UV-irradiation was gradual on the LPCVD-layer.
ZnO Heteroepitaxy on Sapphire Using a Novel Buffer Layer of Titanium Oxide: Optoelectronic Behavior  [PDF]
Satoshi Yamauchi, Yoh Imai
Crystal Structure Theory and Applications (CSTA) , 2013, DOI: 10.4236/csta.2013.23014
Abstract:

Optoelectronic property of ZnO epitaxial layer grown by plasma-assisted epitaxy at temperature as low as 340°C using Ti2O3 buffer layer on a-sapphire were studied by low temperature photoluminescence at 10 K comparing to the layers on c-sapphire and a-sapphire without the buffer layer. The near band-edge emission consisting of free-exciton emissions and neutral-donor bound exciton emissions was significantly dependent on the buffer thickness and dominated by the free-exciton emissions in the layer grown on the very thin buffer layer about 0.8 nm, whereas the intense emissions by neutral-donor bound excitons were observed in the ZnO layer on c-sapphire. The structural behavior indicated the donor was originated from the three-dimensional growth of ZnO layer and details of the optoelectronic feature suggested the residual donors were Al and interstitial-Zn.

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