Sophia University

About: Sophia University is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Nonlinear system & Catalysis. The organization has 4986 authors who have published 7657 publications receiving 106567 citations. The organization is also known as: Jōchi Daigaku.

Primitive Spatial Graphs and Graph Minors

Abstract: Robertson, Seymour, and Thomas characterized linkless embeddings of graphs by flat embeddings, and determined the obstruction set for linkless embeddings. In this paper, we extend flat embeddings to ?primitive embeddings? as linkless embeddings to knotless embeddings. Although the obstruction set for knotless embeddings has not been determined, fundamental theorems and conjectures are obtained.

Reporting a Unique Example of Electronic Bistability Observed in the Form of Valence Tautomerism with a Copper(II) Helicate of a Redox-Active Nitrogenous Heterocyclic Ligand

Abstract: Valence tautomeric compounds involving nondixolene-type ligands are rare. The triple-helicate copper(II) complex [CuII2(L)3](ClO4)4·3CH3CN (1) containing a redox-active N-heterocyclic ligand (L) has been prepared and displays VT equilibrium in solution, as established by electronic spectroscopy, electron paramagnetic resonance spectroscopy, and cyclic and differential pulse voltammetry carried out at variable temperatures. The process involves intramolecular transfer of an electron from one of the L ligands to a copper(II) center, leading to the oxidation of L to an L•+ radical with concomitant reduction of the CuII center to CuI, as shown by the equilibrium [CuIICuIL•+L2]4+ ⇄ [CuII2L3]4+.

Hoop Stress Modification, Stress Hysteresis and Degradation of a REBCO Coil Due to the Screening Current Under External Magnetic Field Cycling

Abstract: Degradation of a REBCO coil under external magnetic fields is one of the major technical problems in the field of HTS magnet technology. A possible cause of such degradation is an inhomogeneous hoop stress distribution, or hoop stress modification (both increase and decrease), induced by the screening current. In this work, we investigate such a hoop stress modification by a small coil experiment with a strain measurement and a numerical simulation. An experimental result shows a very high stress increase factor of >4.1, defined by the maximum circumferential stress over BzJR stress, and the simulated result is in qualitative agreements. The strain (stress) shows a hysteresis effect corresponding to the screening current behavior. A large hoop stress modification causes not only a hoop stress increase, but also buckling of the conductor, which induces delamination and micro-clacks of the superconducting layer. We also show the stress modification can be reduced by bonding turns with epoxy.

Organic Ionic Plastic Crystal‐Based Composite Electrolyte with Surface Enhanced Ion Transport and Its Use in All‐Solid‐State Lithium Batteries

Abstract: Solid-state electrolytes have been identified as one of the most attractive materials for the fabrication of reliable and safe lithium batteries. This work demonstrates a facile strategy to prepare highly conductive organic ionic plastic crystal (OIPC) composites by combination of a low weight fraction of Li+ doped OIPC (N-ethyl-N-methylpyrrolidinium bis(fluorosulfonyl)amide, [C2mpyr][FSI]) with commercial poly(vinylidene difluoride) (PVDF) powder. Benefiting from the enhancement of lithium ion dynamics, as evidenced by the solid-state NMR measurements, the composite electrolyte shows an order of magnitude higher conductivity than that of the bulk material. Lithium metal/LiFePO4 cells incorporating the prepared composite electrolytes show impressively high specific capacity and good cycling stability (99.8% coulombic efficiency after 1200 cycles at 2 C, room temperature), which is the first demonstration of long-term cycling performance at such high rate for an OIPC-based electrolyte. The high voltage cathode, LiCo1/3Ni1/3Mn1/3O2 was tested and good rate performance and stable capacities have been achieved.