Yoshihiko Abe

The perfluorinated sulfonate membrane (Nafion ®117)–platinum composites having H+, mono- and bivalent metal ions as counter cations in the membranes were prepared and the bending behaviors of the composites actuated by the step voltage were investigated in deionized water. The bending behaviors of all composites have the same tendency as the composites to bend quickly to the anode side just after applying the step voltage and gradually to bend back to the cathode side in spite of keeping on the

Abstract Flat hemodialysis membranes were prepared from cellulose/ N ‐methylmorpholine‐ N ‐oxide (NMMO) solutions (dope) with different cellulose concentrations (6–8 wt %) by using a phase‐inversion method. The coagulant used was NMMO aqueous solution, of which the NMMO concentration and its temperature were varied in the range of 0 to 50 wt % and 5 to 60°C, respectively. The effects of these preparation conditions on the permeation characteristics, the ultrafiltration rate (UFR) of pure water,

Abstract Two kinds of regenerated cellulose membranes for hemodialysis were prepared from casting solutions of N ‐methylmorpholine‐ N ‐oxide (NMMO) and cuprammonium (denoted NMMO membranes and cuprammonium membranes, respectively). The concentration of cellulose in the casting solution investigated was 6–8 wt %. The permeation characteristics of both membrane series were compared in terms of the ultrafiltration rate (UFR) of pure water, the sieving coefficient (SC) of dextran, and the solute per

A bstract We study the axion strings with the electroweak gauge flux in the DFSZ axion model and show that these strings, called the electroweak axion strings, can exhibit superconductivity without fermionic zeromodes. We construct three types of electroweak axion string solutions. Among them, the string with W -flux can be lightest in some parameter space, which leads to a stable superconducting cosmic string. We also show that a large electric current can flow along the string due to the Pecce

A pseudo-Nambu-Goldstone boson (pNGB) is an attractive candidate for dark matter (DM) due to the simple evasion of the current severe limits of DM direct detection experiments. One of the pNGB DM models has been proposed based on a gauged $U(1{)}_{B\ensuremath{-}L}$ symmetry. The pNGB has long enough lifetime to be a DM and thermal relic abundance of pNGB DM can be fit with the observed value against the constraints on the DM decays from the cosmic-ray observations. The pNGB DM model can be embe

Abstract We propose models to explain the hierarchies of the quark masses and mixing by utilizing the $$S_4^\prime $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>S</mml:mi> <mml:mn>4</mml:mn> <mml:mo>′</mml:mo> </mml:msubsup> </mml:math> modular flavor symmetry. The hierarchy is realized by the modulus $$\tau $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>τ</mml:mi> </mml:math> stabilized at $$\textrm{Im}\,\tau \gg 1$$ <mml:math xmlns:mml

A bstract We study slow-roll inflation model controlled by the modular flavor symmetry. In the model, the modulus field plays a role of inflaton and the introduction of the stabilizer field coupled to a modular form in the superpotential produces the inflaton potential. In order to generate the flat direction for the slow-roll inflation, we consider the Kähler potential corrected by the modular form. It is noted that the modulus field perpendicular to the inflaton direction is stabilized during

A bstract We construct an SU(5) grand unified model in which the hierarchies of the quark and lepton masses and mixing are explained by the $$ {\Gamma}_6^{\prime } $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msubsup> <mml:mi>Γ</mml:mi> <mml:mn>6</mml:mn> <mml:mo>′</mml:mo> </mml:msubsup> </mml:math> modular flavor symmetry. The hierarchies are realized by the Froggatt-Nielsen-like mechanism due to the residual $$ {Z}_6^T $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/M

A bstract A pseudo Nambu-Goldstone boson (pNGB) is a natural candidate of dark matter in that it avoids the severe direct detection bounds. We show in this paper that the pNGB has another different and interesting face with a higher symmetry breaking scale. Such large symmetry breaking is motivated by various physics beyond the standard model. In this case, the pNGB interaction is suppressed due to the Nambu-Goldstone property and the freeze-out production does not work even with sufficiently la

It has been found that a pseudo-Nambu-Goldstone boson dark matter suppresses the amplitude for elastic scattering with nuclei in non-relativistic limit, and thus can naturally evade the strong constraint of dark matter direct detection experiments. In this paper, we show that non-zero elastic scattering cross section can be induced if the mediator mass is as small as momentum transfer. The predicted recoil energy spectrum can differ from that for usual thermal dark matter. Together with the rele

Abstract The effects of drying condition on the performance (ultrafiltration rate, diffusive solute permeability, and sieving) of hemodialysis membranes prepared from cellulose/ N ‐methylmorpholine‐ N ‐oxide (NMMO) solution (NMMO membrane) and cellulose/cuprammonium solution (cuprammonium membrane; the referential membrane) were studied. The drying condition investigated was the glycerin concentration of the solution, which was used to substitute glycerin for the water in the membrane before the

A bstract In this work, the current stability is discussed for cosmic strings with the bosonic superconductivity. A non-vanishing curvature of string generally induce the quantum instability of the current-carrying particle. Its decay rates are explored for various types of model parameters, curved string shapes, and decay processes. As a cosmological application, the stability is examined for superconducting strings in the string network and also for cosmic vortons by evaluating their cosmologi