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Now showing items 1 - 16 of 39

  • 4, 4′-bipyridine as a molecular catalyst for electrochemical hydrogen production

    Uchida, Taro   Sasaki, Yoichi   Ikeshoji, Tamio   Osawa, Masatoshi  

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    Provided is a polymer which can be formed into a cured article having excellent adhesion strength. A polymer which contains a structural unit having a dihydrobenzoxazine ring represented by general formula (1), said polymer being characterized in that the content ratio of the structural unit having a dihydrobenzoxazine ring is 80 mol% or more relative to the total amount of all of structural units in the polymer. (In general formula (1), R1 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms; Ar1 represents a group having an aromatic ring; R2 represents an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a monovalent group represented by the formula -R3-R4; R3 represents an alkanediyl group having 1 to 20 carbon atoms; and R4 represents an aryl group having 6 to 20 carbon atoms.)
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  • A New Method for Assessing Deep Catastrophic Landslide Susceptibility

    UCHIDA, Taro   YOKOYAMA, Osamu   SUZUKI, Ryuji   TAMURA, Keiji   ISHIZUKA, Tadanori  

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  • Exploration of DPP-IV inhibitors with a novel scaffold by multistep in silico screening

    Uchida, Taro   Wakasugi, Masaki   Kitamura, Takahiro   Yamamoto, Tomomi   Asakura, Mitsutoshi   Fujiwara, Ryoichi   Itoh, Tomoo   Fujii, Hideaki   Hirono, Shuichi  

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  • Role of upslope soil pore pressure on lateral subsurface storm flow dynamics

    Uchida, Taro   Asano, Yuko   Mizuyama, Takahisa   McDonnell, Jeffery J.  

    The role of upslope soil pore water pressure on lateral subsurface storm flow dynamics is poorly understood. Further development of hillslope hydrologic models requires new understanding from field understanding. In particular, we need new, quantifiable measures that link upslope soil pore pressure and water table dynamics to the timing and volume of subsurface storm flow. Here we examine the relationship between hillslope-scale pore pressure and lateral outflow from slope base using the fine-temporal-resolution hydrometric data (10 min interval) from two steep unchanneled concave hillslopes, one hillslope (Fudoji) covered by relatively high hydraulic conductivity sandy soil and the other (Toinotani) covered by relatively low hydraulic conductivity clay soil. In both hillslopes, pore pressures in the area close to the slope base were only weakly related to subsurface storm flow dynamics. During periods of storm flow production, hillslope discharge was strongly related to the cross-sectional area of the upslope saturated layer. During slope seepage periods between events, hillslope discharge from the highly permeable hillslope was still related to the upslope cross-sectional subsurface saturated area. However, during this same period at the low-permeability site, hillslope discharge was not related to the upslope subsurface saturated area. Through intersite comparison we show that the soil matrix permeability has a large impact on the hydrological extension of preferential flow and hence the linkage between upslope pore pressure and subsurface storm flow dynamics.
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  • Measurement of NIR-SERS using commercial silver powder

    UCHIDA, Taro   HIGUCHI, Seiichiro  

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  • Seepage area and rate of bedrock groundwater discharge at a granitic unchanneled hillslope

    Uchida, Taro   Asano, Yuko   Ohte, Nobuhito   Mizuyama, Takahisa  

    [ 1] Recent studies have demonstrated the importance of water movement through the bedrock in the rainfall-runoff process on steep hillslopes. However, quantitative information on this process is still limited. The objective of this study was to address the following questions: ( 1) How large is the area where bedrock groundwater seeps into the soil layer, and ( 2) what is the rate of water flow out of the bedrock? To address these questions, detailed hydrological, hydrochemical, and thermal measurements were conducted at a forested steep unchanneled granitic concave slope in the Tanakami Mountains, central Japan. The relationship between the amplitude of annual soil temperature variation and the measurement depth showed that in a normal low-flow period, the seepage area ranged between 14 and 21 m 2 and the ratio of this area to that of the whole catchment was about 2.0%. In a drought period the seepage area ranged between 3.5 and 5.5 m(2), and the ratio to the whole catchment was around 0.5%. The variation in the area of seepage was controlled both by the short-term precipitation pattern during the preceding several weeks and by the long-term pattern over several preceding months. A two-component geochemical hydrograph separation indicated that the ratio of bedrock groundwater to streamflow was about 0.82 for the normal low-flow periods and 0.90 for the drought period. The rate of flow out of the bedrock into the soil layer ranged from 0.5 to 3.3 m(3) d(-1). That is, although the seepage area was small (0.5-2.0% of the catchment), the contribution of bedrock groundwater was considerable (50-95% of streamflow).
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  • SEIRAS studies of water structure at the gold electrode surface in the presence of supported lipid bilayer

    Uchida, Taro   Osawa, Masatoshi   Lipkowski, Jacek  

    Surface-enhanced infrared absorption spectroscopy (SEIRAS) was employed to study structure of water in a phospholipid bilayer deposited at a gold electrode surface. The technique employs attenuated total reflection (ATR) and an enhancement of the electric field of the IR photon that decays steeply with distance from the metal surface. These conditions allow one to subtract the background from the bulk water and to determine spectra of water in the bilayer or in a confined space between the metal surface and the bilayer. The IR data demonstrated that three types of water are present in the supported bilayer. At potentials close to zero charge the polar heads of the phospholipid molecules retain hydration water. At intermediate charge densities water penetrating deeply into the bilayer and multimers of water molecules were detected in the bilayer. At charge densities more negative than -20 mu C/cm(2) the bilayer is lifted from the metal surface and liquid like water appears in the space separating the bilayer from the metal. (C) 2013 Elsevier B.V. All rights reserved.
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  • Sediment yield on a devastated hill in southern China: effects of microbiotic crust on surface erosion process

    Uchida, Taro   Ohte, Nobuhito   et. al.  

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  • Runout Characteristics and Grain Size Distribution of Large-scale Debris Flows Triggered by Deep Catastrophic Landslides

    NISHIGUCHI, Yuki   UCHIDA, Taro   TAKEZAWA, Nagazumi   ISHIZUKA, Tadanori   MIZUYAMA, Takahisa  

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  • Effects of the lateral and vertical expansion of the water flowpath in bedrock on temporal changes in hillslope discharge

    Uchida, Taro   Miyata, Shusuke   Asano, Yuko  

    Many researchers have emphasized that water flow through fractured bedrock is a dominant contributor to water runoff from hillslopes during baseflow. However, the first-order (main or dominant) controls on water flow through fractured bedrock are not fully understood. We measured the water flow rate from 12 bedrock fractures in a first-order catchment in Ibi, central Japan. Here we showed that the depth of the hydrologically active bedrock controlled temporal changes in water flow rate from bedrock fractures, whereas the contributing area of flow in the hydrologically active bedrock had only a small impact on temporal changes in water flow rate from bedrock fractures. This indicated that although previous studies have mainly examined the influence of lateral expansion of flowpaths on the hillslope discharge, the role of vertical expansion of flowpaths on the hillslope discharge can be important.
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  • Probing the Electrochemical Interface by Surface-Enhanced Infrared Absorption Spectroscopy with ATR Configuration (ATR-SEIRAS)

    Uchida, Taro   Osawa, Masatoshi  

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  • Effects of pipe flow and bedrock groundwater on runoff generation in a steep headwater catchment in Ashiu, central Japan

    Uchida, Taro   Kosugi, Ken\"ichirou   Mizuyama, Takahisa  

    [1] It has been suggested that pipe flow and bedrock groundwater play important roles in storm runoff generation. We examined the effects of pipe flow on storm runoff generation and the roles of bedrock groundwater in rainfall-runoff phenomena in a steep headwater catchment in central Japan. Measurements of pore water pressures, pipe flow, and streamflow showed that when the total rainfall amount was <30 mm, the runoff process could be explained by Darcy's law using the saturated hydraulic conductivity values core samples. When the total rainfall was >70 mm, the dominant runoff process shifted to pipe flow. Temperature measurements indicated four key points: (1) During base flow conditions (streamflow <0.1 mm h(-1)), bedrock groundwater dominated streamflow; (2) during storm flow conditions (streamflow >0.2 mm h(-1)) the source of pipe flow was the same as the streamflow; (3) the transient groundwater at the upper hillslope was commonly dominated by the preevent soil water; and (4) only after the large storms with wet antecedent conditions, was water emerging from the bedrock and mixing with preevent soil water in the transient saturated area at the upper hillslope. Both the hydrometric and temperature measurements indicated that once pipe flow occurs, the contributing area of streamflow extended to upper hillslope, and the transient groundwater at the upper hillslope was delivered to the stream via preferential flow paths, shortcutting the normal mixing process through the soil matrix.
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  • Hydrogen Evolution Reaction Catalyzed by Proton-Coupled Redox Cycle of 4,4′-Bipyridine Monolayer Adsorbed on Silver Electrodes

    Uchida, Taro   Mogami, Hirokazu   Yamakata, Akira   Sasaki, Yoichi   Osawa, Masatoshi  

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  • Is Physisorption Useful for Fine Pore Structure Control? Control of the Pore Structure and Properties of SBA-15 by Paraffin Physisorption

    Uchida, Taro   Deguchi, Minoru   Asakura, Keisuke   Ozeki, Sumio   Iiyama, Taku  

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  • Effects of episodic sediment supply on bedload transport rate in mountain rivers. Detecting debris flow activity using continuous monitoring

    Uchida, Taro   Sakurai, Wataru   Iuchi, Takuma   Izumiyama, Hiroaki   Borgatti, Lisa   Marcato, Gianluca   Pasuto, Alessandro  

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