6,828 research outputs found
A survey of the three-dimensional high Reynolds number transonic wind tunnel
The facilities for aerodynamic testing of airplane models at transonic speeds and high Reynolds numbers are surveyed. The need for high Reynolds number testing is reviewed, using some experimental results. Some approaches to high Reynolds number testing such as the cryogenic wind tunnel, the induction driven wind tunnel, the Ludwieg tube, the Evans clean tunnel and the hydraulic driven wind tunnel are described. The level of development of high Reynolds number testing facilities in Japan is discussed
Flexible control of the Peierls transition in metallic C polymers
The metal-semiconductor transition of peanut-shaped fullerene (C)
polymers is clarified by considering the electron-phonon coupling in the uneven
structure of the polymers. We established a theory that accounts for the
transition temperature reported in a recent experiment and also suggests
that is considerably lowered by electron doping or prolonged irradiation
during synthesis. The decrease in is an appealing phenomenon with regard
to realizing high-conductivity C-based nanowires even at low
temperatures.Comment: 3 pages, 3 figure
Pressure-induced enhancement of superconductivity and superconducting-superconducting transition in CaC
We measured the electrical resistivity, , of superconducting
CaC at ambient and high pressure up to 16 GPa. For 8 GPa, we found
a large increase of with pressure from 11.5 up to 15.1 K. At 8 GPa,
drops and levels off at 5 K above 10 GPa. Correspondingly, the residual
increases by 200 times and the behavior
becomes flat. The recovery of the pristine behavior after depressurization is
suggestive of a phase transition at 8 GPa between two superconducting phases
with good and bad metallic properties, the latter with a lower and more
static disorder
Fulde-Ferrell-Larkin-Ovchinnikov state in a perpendicular field of quasi two-dimensional CeCoIn5
A Fulde-Ferrell-Larkin-Ovchinnkov (FFLO) state was previously reported in the
quasi-2D heavy fermion CeCoIn5 when a magnetic field was applied parallel to
the ab-plane. Here, we conduct 115^In NMR studies of this material in a
PERPENDICULAR field, and provide strong evidence for FFLO in this case as well.
Although the topology of the phase transition lines in the H-T phase diagram is
identical for both configurations, there are several remarkable differences
between them. Compared to H//ab, the FFLO region for H perpendicular to the
ab-plane shows a sizable decrease, and the critical field separating the FFLO
and non-FFLO superconducting states almost ceases to have a temperature
dependence. Moreover, directing H perpendicular to the ab-plane results in a
notable change in the quasiparticle excitation spectrum within the planar node
associated with the FFLO transition.Comment: 5 pages, 3 figure
An energy scale directly related to superconductivity in the high- cuprate superconductors: Universality from the Fermi arc picture
We have performed a temperature dependent angle-resolved photoemission
spectroscopy (ARPES) study of the tri-layer high- cuprate superconductor
(HTSC) BiSrCaCuO (Bi2223), and have shown that
the \textquotedblleft effective\textquotedblright superconducting (SC) gap
defined at the end point of the Fermi arc and the (=
110 K) approximately satisfies the weak-coupling BCS-relationship
2 = 4.3. Combining this result with previous
ARPES results on single- and double-layer cuprates, we show that the
relationship between 2 = 4.3 holds for various
HTSCs. Furthermore, at , the quasi-patricle width at the end
point of the Fermi arc is found to coincide with , consistent
with the context of Planckian dissipation.Comment: 5 pages, 4 figure
The interplay of ethics and genetic technologies in balancing the social valuation of the human genome in UNESCO declarations.
This study investigates changes in the social valuation of the human genome over the more than 30 years since the establishment of the Human Genome Project. It offers a descriptive sociological analysis of the three waves of this valuation, mainly by considering three key UNESCO declarations and a relevant report. These waves represent a shifting balance between collectivism and individualism, starting with a broadly constructed valuation of the human genome as common human heritage and moving toward a valuation of dynamic applications within various social and medical contexts (e.g., personalized genomic medicine and genome editing). We seek to broaden the analytical perspective by examining how the declarations' ethical foci are framed within the context of rapidly evolving genetic technologies and their social applications. We conclude by discussing continuity and change in value balancing vis-à-vis changing genomic technologies
Effect of electron-phonon coupling in the ARPES spectra of the tri-layer cuprate BiSrCaCuO
Angle-resolved photoemission spectroscopy using tunable low energy photons
allows us to study the quasi-particle (QP) dispersions of the inner and outer
CuO2 planes (IP and OP) separately in the tri-layer cuprate
BiSrCaCuO (Bi2223). The kink energy of the OP
band is 70 meV, as observed in various high- cuprates, while that
of the IP band is as large as 100 meV in the superconducting (SC) state. This
large kink energy is attributed to the 35 meV buckling mode plus the
large ( 60 meV) SC gap of IP. The IP band also shows a weak kink feature
at 70 meV in the SC state. The latter feature can be explained either by the 70
meV half-breathing mode or by the 35 meV buckling-phonon mode plus the
40 meV SC gap of OP if interlayer scattering of QP is involved.Comment: 5 pages, 2 figure
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