155 research outputs found
A Method for Project Member Role Assignment in Open Source Software Development Using Self-Organizing Maps
Design of tapered polarization splitter based on EC-CHFs by full-vectorial FE-BPM using coordinate transformation
We propose and design a tapered polarization splitter (PS) using the single-polarization property of an elliptical-hole core circular-hole holey fiber (EC-CHF). It is reported that polarization splitting without any crosstalk is enabled using the PS with EC-CHF. In this paper, we show that the mode coupling is enhanced with a tapered PS structure, and the full waveguide separation at the input and output ends can be simultaneously realized. We also propose a full-vectorial finite element beam propagation method using coordinate transformation to efficiently analyze a waveguide whose structure varies along the longitudinal direction. In this approach, computational accuracy and efficiency are greatly improved. (C) 2020 Optical Society of Americ
Dynamic nuclear polarization and Knight shift measurements in a breakdown regime of integer quantum Hall effect
Nuclear spins are polarized electrically in a breakdown regime of an
odd-integer quantum Hall effect (QHE). Electron excitation to the upper Landau
subband with the opposite spin polarity flips nuclear spins through the
hyperfine interaction. The polarized nuclear spins reduce the spin-splitting
energy and accelerate the QHE breakdown. The Knight shift of the nuclear spins
is also measured by tuning electron density during the irradiation of
radio-frequency magnetic fields.Comment: 3 pages, 2 figures, EP2DS-1
Nucleation process in the Burridge-Knopoff model of earthquakes
Nucleation process of the one-dimensional Burridge-Knopoff model of
earthquakes obeying the rate- and state-dependent friction law is studied both
analytically and numerically. The properties of the nucleation dynamics, the
nucleation lengths and the duration times are examined together with their
continuum limits.Comment: Title changed, one figure (previous Fig.2) omitted, several
references (new Refs.5-8,21,24-28) added, and two eqs. (new eqs.1,5) added.
Text expanded considerably, especially the part explaining the relation of
the model to the elastic continuum model. To appear in Europhys. Letter
Coherent manipulation of nuclear spins in the breakdown regime of integer quantum Hall states
We demonstrate a new method for electrical manipulation of nuclear spins
utilizing dynamic nuclear polarization induced by quantum Hall effect
breakdown. Nuclear spins are polarized and detected through the hyperfine
interaction between a nuclear spin system and a two-dimensional electron system
located at an interface of GaAs/AlGaAs single heterostructure. Coherent
oscillations between the nuclear-spin quantum states are observed by measuring
the longitudinal voltage of the conductor.Comment: 4 pages, 2 figure
- …