859 research outputs found
Interface Landau levels in graphene monolayer-bilayer junction
Electronic structure of graphene monolayer-bilayer junction in a magnetic
field is studied within an effective-mass approximation. The energy spectrum is
characterized by interface Landau levels, i.e., the locally flat bands
appearing near the boundary region, resulting in a series of characteristic
peaks in the local density of states. Their energies are independent of
boundary types such as zigzag or armchair. In the atomic scale, the local
density of states shows a Kekul\'{e} pattern due to the valley mixing in the
armchair boundary, while does not in the zigzag boundary.Comment: 12 pages, 9 figure
Numerical Study of Inelastic Scatterings by Time-Dependent Random Potentials in Two-Dimensional Systems
Diffusion of electrons in a two-dimensional system with time-dependent random
potentials is investigated numerically. In the absence of spin-orbit
scattering, the conductivity shows universal weak localization correction. In
the presence of it, however, the correction to the conductivity weakly depends
on the strength of disorder, and becomes vanishingly small close to the
metal-insulator transition point.Comment: 4 pages, 2 figures, Physica B in press, Proceedings for EP2DS-1
Intersubband absorption linewidth in GaAs quantum wells due to scattering by interface roughness, phonons, alloy disorder, and impurities
We calculate the intersubband absorption linewidth in quantum wells (QWs) due
to scattering by interface roughness, LO phonons, LA phonons, alloy disorder,
and ionized impurities, and compare it with the transport energy broadening
that corresponds to the transport relaxation time related to electron mobility.
Numerical calculations for GaAs QWs clarify the different contributions of each
individual scattering mechanism to absorption linewidth and transport
broadening. Interface roughness scattering contributes about an order of
magnitude more to linewidth than to transport broadening, because the
contribution from the intrasubband scattering in the first excited subband is
much larger than that in the ground subband. On the other hand, LO phonon
scattering (at room temperature) and ionized impurity scattering contribute
much less to linewidth than to transport broadening. LA phonon scattering makes
comparable contributions to linewidth and transport broadening, and so does
alloy disorder scattering. The combination of these contributions with
significantly different characteristics makes the absolute values of linewidth
and transport broadening very different, and leads to the apparent lack of
correlation between them when a parameter, such as temperature or alloy
composition, is changed. Our numerical calculations can quantitatively explain
the previously reported experimental results.Comment: 17 pages, including 15 figure
Long-term maintenance of human induced pluripotent stem cells by automated cell culture system.
自動培養装置によるヒトiPS細胞の長期間培養に成功 . 京都大学プレスリリース. 2015-11-27.Pluripotent stem cells, such as embryonic stem cells and induced pluripotent stem (iPS) cells, are regarded as new sources for cell replacement therapy. These cells can unlimitedly expand under undifferentiated conditions and be differentiated into multiple cell types. Automated culture systems enable the large-scale production of cells. In addition to reducing the time and effort of researchers, an automated culture system improves the reproducibility of cell cultures. In the present study, we newly designed a fully automated cell culture system for human iPS maintenance. Using an automated culture system, hiPS cells maintained their undifferentiated state for 60 days. Automatically prepared hiPS cells had a potency of differentiation into three germ layer cells including dopaminergic neurons and pancreatic cells
Flood Surface Flow Measurement by STIV in Adverse Conditions for Imaging
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv
Identification and Radiofrequency Catheter Ablation of a Nonsustained Atrial Tachycardia at the Septal Mitral Annulus with the Use of a Noncontact Mapping System: A Case Report
AbstractHere we report a case of a 16-year old female with symptomatic nonsustained atrial tachycardia (NSAT) originating from the septal mitral annulus. NSAT was induced by atrial burst pacing after an intravenous isoproterenol (ISP) injection. The array mode of the noncontact mapping system (NCM) allowed us to quickly identify the tachycardia focus at the septal mitral annulus, where the contact bipolar voltage map revealed no low voltage area (<0.5 mV). The NSAT was eliminated by a radiofrequency energy application to the identified tachycardia focus during sinus rhythm, and the patient has been free from any symptoms during 10 months of follow-up
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