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.

Anomaly of N = 8 shell closure in neutron-rich Be and B isotopes studied via delayed neutron emitting 14 Be β decay

Abstract: We investigated the $\ensuremath{\beta}$ decay of the neutron drip line nucleus ${}^{14}\mathrm{Be}$ by means of double and triple coincidence measurements of $\ensuremath{\beta}$ rays, delayed neutrons, and $\ensuremath{\gamma}$ rays. The decay sequences were established and new values of the half-life and branching ratios were obtained. The decay scheme obtained is characterized by a single dominant branch leading to a ${1}^{+}$ state in ${}^{14}\mathrm{B}$ with a branching ratio of $(91\ifmmode\pm\else\textpm\fi{}9)%,$ which subsequently emits a delayed neutron with an energy of $288\ifmmode\pm\else\textpm\fi{}8 \mathrm{keV}.$ The excitation energy and width of the ${1}^{+}$ state were determined to be $1.28\ifmmode\pm\else\textpm\fi{}0.02 \mathrm{MeV}$ and $49\ifmmode\pm\else\textpm\fi{}2 \mathrm{keV},$ respectively. The excitation energy and width of this level as well as the $\mathrm{log}\mathrm{ft}$ value were treated in terms of a simple shell model and found to be strongly related to the $N=8$ shell gap quenching ${\mathrm{in}}^{13,14}\mathrm{B}$ and ${}^{12}\mathrm{Be}.$

Torque Observers Design for Spark Ignition Engines With Different Intake Air Measurement Sensors

Abstract: This paper presents a design approach and an experimental evaluation of torque observers for Spark Ignition (SI) engines. An engine model simplified from the generally used mean value model is proposed. Based on the developed model, torque observers are designed for engine systems with different intake air measurement sensors. The torque production model is introduced first to give a nominal value of torque estimation. Then, using the rotational dynamic equation of the crankshaft, an online adjusting term is added to modify the nominal estimation. The intake pressure, as an input of the torque production model, is directly measured if a pressure sensor is used. When an air mass flow sensor is adopted instead, an additional intake pressure observer is included in the torque observer. Simulation and experimental results are shown finally to demonstrate the proposed observers.

Multiferroism at Room Temperature in BiFeO3/BiCrO3(111) Artificial Superlattices

Abstract: We report the fabrication of BiFeO3/BiCrO3(111) artificial superlattices with 1/1 stacking in a layer-by-layer growth mode on atomically flat SrTiO3(111) surfaces. While BiFeO3 and BiCrO3 are antiferromagnets having Fe–O–Fe and Cr–O–Cr bonds, these superlattices contain Fe–O–Cr bonds, in which ferromagnetic interaction is expected. Magnetization measurements at 300 K revealed that the magnetic moment per transition metal ion was 1.7 µB, suggesting ferromagnetic spin order. Ferroelectric behavior at room temperature was confirmed by an analysis using a scanning non-linear dielectric microscope.