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Hokkaido University Collection of Scholarly and Academic Papers (130.615 recursos)

HUSCAP (Hokkaido University Collection of Scholarly and Academic Papers) contains peer-reviewed journal articles, proceedings, educational resources and any kind of scholarly works of Hokkaido University.

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Mostrando recursos 1 - 20 de 1.747

  1. Development of Numerical Heat Transfer and the Structural Model to Design Slim and Translucent Vacuum Layer Type Insulation Panels to Retrofitting Insulation in Existing Buildings

    Yang, Zhang; Katsura, Takao; Aihara, Masahiro; Nakamura, Makoto; Nagano, Katsunori
    The authors develop slim and light-weight vacuum insulation panels (VIPs) by producing vacuum layers with spacers and plastic plates. The developed VIPs have the advantages of a low cost and easy installation, thus facilitating retrofitting insulation of existing buildings. In addition, one of the developed VIPs is slim and translucent so it can be easily used for windows in an internal installation. In this paper, the authors first propose a vacuum layer type slim translucent VIP and focus on a reasonable design method. Next, the authors introduce the design process in which the structural design is obtained with element mechanical...

  2. Characteristics of Microfluidic Paper-based Analytical Devices Fabricated by Four Different Methods

    Komatsu, Takeshi; Maeki, Masatoshi; Ishida, Akihiko; Tani, Hirofumi; Tokeshi, Manabu
    We report on the effects of fabrication methods, photolithography, wax printing, screen printing, and craft cutting, on selected properties of microfluidic paper-based analytical devices (mu PADs): cost, fabrication precision, wicking rate, and analytical accuracy. Photolithography requires numerous fabrication steps, and an oxygen plasma treatment is necessary when using an aqueous solution. Although the boundary between the hydrophobic and hydrophilic areas in the mu PAD is sharpest, the obtained K-scale intensity in measuring of protein concentrations is lower than those of the devices by other methods. Wax printing offers the simplest and fastest fabrication, although solution leakage measures should be taken...

  3. Kinetic boundary conditions for vapor–gas binary mixture

    Kobayashi, Kazumichi; Sasaki, Kiyofumi; Kon, Misaki; Fujii, Hiroyuki; Watanabe, Masao
    Using molecular dynamics simulations, the present study investigated the precise characteristics of the binary mixture of condensable gas (vapor) and non-condensable gas (NC gas) molecules creating kinetic boundary conditions (KBCs) at a gas–liquid interface in equilibrium. We counted the molecules utilizing the improved two-boundary method proposed in previous studies by Kobayashi et al. (Heat Mass Trans 52:1851–1859, 2016.doi:10.1007/s00231-015-1700-6). In this study, we employed Ar for the vapor molecules, and Ne for the NC gas molecules. The present method allowed us to count easily the evaporating, condensing, degassing, dissolving, and reflecting molecules in order to investigate the detailed motion of the...

  4. 壊滅的な災害の予防(1)

    藤井, 義明

  5. Theoretical analysis of angular distribution of scattering in nozzle components using a response-function method for proton spot-scanning therapy

    Ueda, Hideaki; Furusaka, Michihiro; Matsuura, Taeko; Hirayama, Shusuke; Umegaki, Kikuo
    In spot-scanning proton therapy, highly precise beam control is required in the treatment nozzle such that the proton beam does not spread out during transportation by restraining the divergence of the beam angle and spot size, simultaneously. In order to evaluate the beam-broadening behaviour induced by passing through the various nozzle components, we have developed a new method to calculate the angular divergence profile of a proton beam in the nozzle. The angular divergence of the proton beam for each nozzle component is calculated by the Monte Carlo simulation code, Geant4, assuming that the initial beam has no divergence. The...

  6. A force evaluation free method to N-body problems: Binary interaction approximation

    Oikawa, S
    We recently proposed the binary interaction approximation (BIA) to N-body problems, which, in principle, excludes the interparticle force evaluation if the exact solutions are known for the corresponding two-body problems such as the Coulombic and gravitational interactions. In this article, a detailed introduction to the BIA is given, including the error analysis to give the expressions for the approximation error in the total angular momentum and the total energy of the entire system. It is shown that, although the energy conservation of the BIA scheme is worse than the 4th order Hermite integrator (HMT4) for similar elapsed, or the wall-clock...

  7. Time-domain imaging of gigahertz surface waves on an acoustic metamaterial

    Otsuka, Paul H.; Mezil, Sylvain; Matsuda, Osamu; Tomoda, Motonobu; Maznev, Alexei A.; Gan, Tian; Fang, Nicholas; Boechler, Nicholas; Gusev, Vitalyi E.; Wright, Oliver B.
    We extend time-domain imaging in acoustic metamaterials to gigahertz frequencies. Using a sample consisting of a regular array of similar to 1 mu mdiameter silica microspheres forming a two-dimensional triangular lattice on a substrate, we implement an ultrafast technique to probe surface acoustic wave propagation inside the metamaterial area and incident on the metamaterial from a region containing no microspheres, which reveals the acoustic metamaterial dispersion, the presence of band gaps and the acoustic transmission properties of the interface. A theoretical model of this locally resonant metamaterial based on normal and shear-rotational resonances of the spheres fits the data well....

  8. Copper(I)-Catalyzed Enantioselective Boryl Substitution of Allyl Acylals: An Efficient Approach for Enantioenriched -Chiral -Acetoxyallylboronates

    Takenouchi, Yuta; Kojima, Ryoto; Momma, Riko; Ito, Hajime
    A novel approach has been developed for the enantioselective synthesis of -chiral -acetoxyallylboronates via the copper(I)-catalyzed -boryl substitution of allyl acylals. This reaction proceeded with high E/Z selectivity and enantioselectivity (E/Z = >99:1, up to 80% yield, up to 99% ee). The subsequent allylation of aldehyde with the allylboronate afforded the monoprotected anti-1,2-diol derivative with high stereoselectivity.

  9. Numerical simulations of magnetic resonance elastography using finite element analysis with a linear heterogeneous viscoelastic model

    Tomita, Sunao; Suzuki, Hayato; Kajiwara, Itsuro; Nakamura, Gen; Jiang, Yu; Suga, Mikio; Obata, Takayuki; Tadano, Shigeru
    Magnetic resonance elastography (MRE) is a technique to identify the viscoelastic moduli of biological tissues by solving the inverse problem from the displacement field of viscoelastic wave propagation in a tissue measured by MRI. Because finite element analysis (FEA) of MRE evaluates not only the viscoelastic model for a tissue but also the efficiency of the inversion algorithm, we developed FEA for MRE using commercial software called ANSYS, the Zener model for displacement field of a wave inside tissue, and an inversion algorithm called the modified integral method. The profile of the simulated displacement field by FEA agrees well with...

  10. Biosynthesis of the Carbonylmethylene Structure Found in the Ketomemicin Class of Pseudotripeptides

    Kawata, Junpei; Naoe, Taiki; Ogasawara, Yasushi; Dairi, Tohru
    We recently discovered novel pseudotripeptides, the ketomemicins, which possess a C-terminal pseudodipeptide connected with a carbonylmethylene instead of an amide bond, through heterologous expression of gene clusters identified in actinobacteria. The carbonylmethylene structure is a stable isostere of the amide bond and its biological significance has been shown in several natural and synthetic products. Despite the biological importance of these compounds, little is known about how the carbonylmethylene structure is biosynthesized. In this work, we fully characterized the biosynthetic machinery of the pseudodipeptide. An aldolase, dehydratase, PLP-dependent glycine-C-acetyltransferase, and dehydrogenase were involved in the formation of the pseudodipeptide, with malonyl-CoA...

  11. ヒドロキシシクロヘキサジエニルラジカルの光化学 : 1 メトキシ置換ベンゼン類

    住吉, 孝

  12. Influence of the Porous Structure of the Cathode on the Discharge Capacity of Lithium-Air Batteries

    Sakai, Kazuki; Iwamura, Shinichiroh; Mukai, Shin R.
    In the development of lithium-air batteries, to understand how the porous structure of the cathode affects the performance of the battery system is important because the main electrochemical reaction which occurs in this system is the deposition of Li2O2 in the pores of the cathode. To clarify the relationship between the porous structure of the cathode and the performance of the battery system, we used carbon gels with different pore size distributions as model cathodes and investigated how their pores are filled during discharging by analyzing the structure of cathodes discharged to different depths through N-2 adsorption experiments. The dominant...

  13. Tunable-phi Josephson junction with a quantum anomalous Hall insulator

    Sakurai, Keimei; Ikegaya, Satoshi; Asano, Yasuhiro
    We theoretically study the Josephson current in a superconductor/quantum anomalous Hall insulator/superconductor junction by using the lattice Green function technique. When an in-plane external Zeeman field is applied to the quantum anomalous Hall insulator, the Josephson current J flows without a phase difference across the junction theta. The phase shift phi appearing in the current-phase relationship J alpha sin(theta - phi) is proportional to the amplitude of Zeeman fields and depends on the direction ofZeeman fields. Aphenomenological analysis of the Andreev reflection processes explains the physical origin of phi. In a quantum anomalous Hall insulator, time-reversal symmetry and mirror-reflection symmetry...

  14. Excitation energy dependence of initial phase shift in Kerr rotation of resident electron spin polarization in a CdTe single quantum well

    Yan, L. -P.; Takamure, T.; Kaji, R.; Karczewski, G.; Takeyama, S.; Adachi, S.
    The generation dynamics of a resident electron spin polarization involve the formation and transformation of the associated optically excited states depending on the excitation photon energy. Initial phase shift in the precession of a resident electron spin polarization gives the important clues to reveal the interplay between the associated excited states and resident electrons. In this work, the excitation energy dependence of the initial phase shift in Kerr rotation of a resident electron spin polarization is investigated in a CdTe/Cd0.85Mg0.15Te single quantum well under a low magnetic field. Through the careful analysis of the spin precession, the excited electron-heavy-hole pairs...

  15. Effective Photo- and Triboluminescent Europium(III) Coordination Polymers with Rigid Triangular Spacer Ligands

    Hasegawa, Yasuchika; Tateno, Shiori; Yamamoto, Masanori; Nakanishi, Takayuki; Kitagawa, Yuichi; Seki, Tomohiro; Ito, Hajime; Fushimi, Koji
    Luminescent Eu-III coordination polymers with rigid triangular spacer ligands are reported. The Eu-III coordination polymer, [Eu-3(hfa)(9)(tppb)(2)](n) (hfa: hexafluoroacetylacetonate, tppb: tris(4-diphenylphosphorylphenyl) benzene), shows high thermo-stability (decomposition temperature= 354 degrees C) and photoluminescence quantum yield (Phi(4f-4f)= 82%, photosensitized energy transfer efficiency= 78%). The tribolumines-cence efficiency of Eu-III coordination polymer with triangular spacers under laser pulse irradiation (Nd:YAG, lambda= 1064 nm, pulse width= 5 ns, pulse energy= 0.1 mJ) is calculated to be 49%. Characteristic triangular structure, high emission quantum yield, effective photosensitized energy transfer, and remarkable triboluminescence properties of Eu-III coordination polymers are demonstrated for the first time.

  16. Feasibility study of decay heat uncertainty reduction using nuclear data adjustment method with experimental data

    Kawamoto, Yosuke; Chiba, Go
    The accurate prediction of the decay heat is essential, especially for nuclear power plant safety purposes. However, it is known that the decay heat predicted by nuclear fuel burn-up calculations is uncertain because of uncertainty of nuclear data employed in the calculations. If the decay heat uncertainty can be reduced, the safety margin of the predicted decay heat can also be reduced, and feasible design ranges of various types of equipments related to the decay heat can be extended. In the present study, we use the nuclear data adjustment method for the decay heat uncertainty reduction with several types of...

  17. Quantitative evaluation of mass transfer near the edge of porous media by absorption photometry

    Tanikoshi, Taiki; Otomo, Ryoko; Harada, Shusaku
    The intensive investigation of mass transfer near the entrance (edge) of porous media by quantification of the surrounding concentration field has been performed. We have adopted a noninvasive and real-time system based on light absorption photometry for measurement of the concentration field in a quasi-two dimensional cell. This system is, in principle, applicable to the measurement of various substances due to the generality of light absorption. This measurement system was applied to a simple model of the gravity-driven transport of a substance in a fluid near the edge of a porous medium in the presence of a reaction at the...

  18. Temperature measurements near the heating surface at high heat fluxes in pool boiling of 2-propanol/water mixtures

    Sakashita, Hiroto
    To examine the mechanism of CHF enhancement with binary mixtures, this paper measured local temperatures close to a heating surface using a micro-thermocouple at high heat fluxes for pool boiling of a 3 mol% of 2-propanol/water mixture on an upward-facing 12 mm diameter circular surface. The variations in temperature traces measured at various locations above the heating surface indicate that the distributions of 2-propanol concentration have strong non-uniformities in the vertical and radial directions: 2-propanol concentration is higher in the vicinity of the heating surface at the central part of the heating surface and lower in the periphery of the...

  19. Discussion on size effect of footing in ultimate bearing capacity of sandy soil using rigid plastic finite element method

    Nguyen, Du L.; Ohtsuka, S.; Hoshina, T.; Isobe, K.
    Currently, many formulas are used to calculate the ultimate bearing capacity. However, these formulas have disadvantages when being applied in practice since they can only be applied for calculating simple footing shapes and uniform grounds. Most formulas do not take into account the size effect of the footing on the ultimate bearing capacity, except for the formula by the Architectural Institute of Japan. The advantage of using the finite element method (FEM) is its applicability to non-uniform grounds, for example, multi-layered and improved grounds, and to complicated footing shapes under three-dimensional conditions. FEM greatly improves the accuracy in estimating the...

  20. Self-ordered Porous Alumina Fabricated via Phosphonic Acid Anodizing

    Akiya, Shunta; Kikuchi, Tatsuya; Natsui, Shungo; Sakaguchi, Norihito; Suzuki, Ryosuke O.
    Self-ordered periodic porous alumina with an undiscovered cell diameter was fabricated via electrochemical anodizing in a new electrolyte, phosphonic acid (H3PO3). High-purity aluminum plates were anodized in phosphonic acid solution under various operating conditions of voltage, temperature, concentration, and anodizing time. Phosphonic acid anodizing at 150-180 V caused the self-ordering behavior of porous alumina, and an ideal honeycomb nanostructure measuring 370-440 nm in cell diameter was successfully fabricated on the aluminum substrate. Conversely, disordered porous alumina grew at below 140 V, and anodizing at above 190 V caused local thickening due to oxide burning. Two-step phosphonic acid anodizing allows the...

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