287 research outputs found
Andreev reflection at the interface with an oxide in the quantum Hall regime
Quantum Hall/superconductor junctions have been an attractive topic as the
two macroscopically quantum states join at the interface. Despite longstanding
efforts, however, experimental understanding of this system has not been
settled yet. One of the reasons is that most semiconductors hosting
high-mobility two-dimensional electron systems (2DES) usually form Schottky
barriers at the metal contacts, preventing efficient proximity between the
quantum Hall edge states and Cooper pairs. Only recently have relatively
transparent 2DES/superconductor junctions been investigated in graphene. In
this study, we propose another material system for investigating
2DES/superconductor junctions, that is ZnO-based heterostrcuture. Due to the
ionic nature of ZnO, a Schottky barrier is not effectively formed at the
contact with a superconductor MoGe, as evidenced by the appearance of Andreev
reflection at low temperatures. With applying magnetic field, while clear
quantum Hall effect is observed for ZnO 2DES, conductance across the junction
oscillates with the filling factor of the quantum Hall states. We find that
Andreev reflection is suppressed in the well developed quantum Hall regimes,
which we interpret as a result of equal probabilities of normal and Andreev
reflections as a result of multiple Andreev reflection at the
2DES/superconductor interface.Comment: 18 pages, 8 figure
Multi-Calorons Revisited
Analytic Nahm data is re-examined for SU(2) calorons, or periodic instantons,
of instanton charge 2. The Nahm equations are solved analytically in terms of
Jacobi elliptic functions and the possible matching conditions are classified.
The dimensions of framed moduli space for charge 2 caloron is enumerated and
the maximal parameter, which is 16 for charge 2, case is identified. The
monopole and instanton limits are also considered. It is found that the Nahm
data which does not correspond to the standard monopoles plays significant role
for calorons.Comment: 29 pages, 3 figures, published versio
Andreev Reflection at the Interface with an Oxide in the Quantum Hall Regime
Quantum Hall/superconductor junctions have been an attractive topic as the two macroscopically quantum states join at the interface. Despite longstanding efforts, however, experimental understanding of this system has not been settled yet. One of the reasons is that most semiconductors hosting high-mobility two-dimensional electron systems (2DES) usually form Schottky barriers at the metal contacts, preventing efficient proximity between the quantum Hall edge states and Cooper pairs. Only recently have relatively transparent 2DES/superconductor junctions been investigated in graphene. In this study, we propose another material system for investigating 2DES/superconductor junctions, that is ZnO-based heterostructure. Due to the ionic nature of ZnO, a Schottky barrier is not effectively formed at the contact with a superconductor MoGe, as evidenced by the appearance of Andreev reflection at low temperatures. With applying magnetic field, while clear quantum Hall effect is observed for ZnO 2DES, conductance across the junction oscillates with the filling factor of the quantum Hall states. We find that Andreev reflection is suppressed in the well developed quantum Hall regimes, which we interpret as a result of equal probabilities of normal and Andreev reflections as a result of multiple Andreev reflection at the 2DES/superconductor interface
The association between embedded catheter implantation and hospitalization costs for peritoneal dialysis initiation: a retrospective cohort study
Background: Compared with the conventional peritoneal dialysis (PD) catheter insertion, embedding PD catheter implantation is one of the procedures for planned PD initiation. However, facilities where embedded PD catheter implantation is available are limited, and the impact of embedded PD catheter implantation on hospitalization cost and length of hospitalization is unknown. Methods: This retrospective single-center cohort study included 132 patients with PD initiation between 2005 and 2020. The patients were divided into two groups: 64 patients in the embedding group and 68 patients in the conventional insertion group. We created a multivariable generalized linear model (GLM) with the gamma family and log-link function to evaluate the association among catheter embedding, the duration and medical costs of hospitalization for PD initiation. We also evaluated the effect modification between age and catheter embedding. Results: Catheter embedding (β coefficient − 0.13 [95% confidence interval − 0.21, − 0.05]) and age (per 10 years 0.08 [0.03, 0.14]) were significantly associated with hospitalization costs. Catheter embedding (− 0.21 [− 0.32, − 0.10]) and age (0.11 [0.03, 0.19]) were also identified as factors significantly associated with length of hospitalization. The difference between the embedding group and the conventional insertion group in hospitalization costs for PD initiation (P for interaction = 0.060) and the length of hospitalization (P for interaction = 0.027) was larger in young-to-middle-aged patients than in elderly patients. Conclusions: Catheter embedding was associated with lower hospitalization cost and shorter length of hospitalization for PD initiation than conventional PD catheter insertion, especially in young-to-middle-aged patients.The version of record of this article, first published in Clinical and Experimental Nephrology, is available online at Publisher’s website: https://doi.org/10.1007/s10157-023-02416-
24-hour measurement of squeezed light using automated stable fiber system
In order to provide a cloud service of optical quantum computing, it is
inevitable to stabilize the optical system for many hours. It is advantageous
to construct a fiber-based system, which does not require spatial alignment.
However, fiber-based systems are instead subject to fiber-specific
instabilities. For instance, there are phase drifts due to ambient temperature
changes and external disturbances, and polarization fluctuations due to the
finite polarization extinction ratio of fiber components. Here, we report the
success of measuring squeezed light with a fiber system for 24 hours. To do
this, we introduce stabilization mechanics to suppress fluctuations in the
fiber system, and integrated controller to automatically align the entire
system. The squeezed light at the wavelength of 1545.3 nm is measured every 2
minutes, where automated alignments are inserted every 30 minutes. The
squeezing levels with the average of -4.42 dB are recorded with an extremely
small standard deviation of 0.08 dB over 24 hours
Tracheal reconstruction using s-shaped skin flaps and a conchal cartilage graft.
We have devised a technique of two-stage tracheal reconstruction using S-shaped skin flaps and an aural conchal cartilage graft. During the first operation, S-shaped skin flaps were elevated before resection of the trachea. A tracheocutaneous fistula was created at the tracheal defect using S-shaped skin flaps while placing the conchal cartilage graft underneath. During the second operation, a skin incision was made around the fistula to elevate the hinge flaps, including the cartilage. The edges of the hinge flaps were sutured to form the tracheal lumen, and the area of the skin defect was then closed with double-rotation skin flaps
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