3,260 research outputs found
Effect of humidity on transonic flow
An experimental investigation of the effects of humidity-induced condensation on shock/boundary-layer
interaction has been conducted in a transonic wind-tunnel test. The test geometry considered was a wall-mounted
bump model inserted in the test section of the wind tunnel. The formation of a λ-shape condensation shock wave was
shown from schlieren visualization and resulted in a forward movement of the shock wave, reduced shock wave
strength, and reduced separation. Empirical correlations of the shock wave strength and humidity/dew point
temperature were established. For humidity levels below 0.15 or a dew point temperature of 268 K, the effect of
humidity was negligible. The unsteady pressure measurements showed that if a condensation shock wave formed and
interacted with a main shock wave, the flow becomes unsteady with periodic flow oscillations occurring at 720 Hz
Fluctuation-Driven First-Order Transition in Pauli-limited d-wave Superconductors
We study the phase transition between the normal and non-uniform
(Fulde-Ferrell-Larkin-Ovchinnikov) superconducting state in quasi
two-dimensional d-wave superconductors at finite temperature. We obtain an
appropriate Ginzburg-Landau theory for this transition, in which the
fluctuation spectrum of the order parameter has a set of minima at non-zero
momenta. The momentum shell renormalization group procedure combined with
dimensional expansion is then applied to analyze the phase structure of the
theory. We find that all fixed points have more than one relevant directions,
indicating the transition is of the fluctuation-driven first order type for
this universality class.Comment: 5 page
Structure of the Fulde-Ferrell-Larkin-Ovchinnikov state in two-dimensional superconductors
Nonuniform superconducting state due to strong spin magnetism is studied in
two-dimensional type-II superconductors near the second order phase transition
line between the normal and the superconducting states. The optimum spatial
structure of the orderparameter is examined in systems with cylindrical
symmetric Fermi surfaces. It is found that states with two-dimensional
structures have lower free energies than the traditional one-dimensional
solutions, at low temperatures and high magnetic fields. For s-wave pairing,
triangular, square, hexagonal states are favored depending on the temperature,
while square states are favored at low temperatures for d-wave pairing. In
these states, orderparameters have two-dimensional structures such as square
and triangular lattices.Comment: 11 pages (LaTeX, revtex.sty), 3 figures; added reference
Computing in String Field Theory Using the Moyal Star Product
Using the Moyal star product, we define open bosonic string field theory
carefully, with a cutoff, for any number of string oscillators and any
oscillator frequencies. Through detailed computations, such as Neumann
coefficients for all string vertices, we show that the Moyal star product is
all that is needed to give a precise definition of string field theory. The
formulation of the theory as well as the computation techniques are
considerably simpler in the Moyal formulation. After identifying a monoid
algebra as a fundamental mathematical structure in string field theory, we use
it as a tool to compute with ease the field configurations for wedge, sliver,
and generalized projectors, as well as all the string interaction vertices for
perturbative as well as monoid-type nonperturbative states. Finally, in the
context of VSFT we analyze the small fluctuations around any D-brane vacuum. We
show quite generally that to obtain nontrivial mass and coupling, as well as a
closed strings, there must be an associativity anomaly. We identify the
detailed source of the anomaly, but leave its study for future work.Comment: 77 pages, LaTeX. v3: corrections of signs or factors (for a list of
corrections see beginning of source file
Characteristics of Japanese wrestlers with respect to function and structure of limbs
It is well known that hypertrophy and strength gain of the human skeletal muscle are induced by muscle training. It has also been shown that the training effect on size and strength of the skeletal muscle are altered the different athletic training protocols (1, 4). From these findings, it seems possible that wrestlers possess the hypertrophied muscle and stronger muscle strength by specific training.
In the present study, we assess the functional and structural characteristics of the skeletal muscle in Japanese wrestlers
Enhancement of the upper critical field and a field-induced superconductivity in antiferromagnetic conductors
We propose a mechanism by which the paramagnetic pair-breaking effect is
largely reduced in superconductors with coexisting antiferromagnetic long-
range and short-range orders. The mechanism is an extension of the Jaccarino
and Peter mechanism to antiferromagnetic conductors, but the resultant phase
diagram is quite different. In order to illustrate the mechanism, we examine a
model which consists of mobile electrons and antiferromagnetically correlated
localized spins with Kondo coupling between them. It is found that for weak
Kondo coupling, the superconductivity occurs over an extraordinarily wide
region of the magnetic field including zero field. The critical field exceeds
the Chandrasekhar and Clogston limit, but there is no lower limit in contrast
to the Jaccarino and Peter mechanism. On the other hand, for strong Kondo
coupling, both the low-field superconductivity and a field-induced
superconductivity occur. Possibilities in hybrid ruthenate cuprate
superconductors and some organic superconductors are discussed.Comment: 5 pages, 1 figure, revtex.sty, to be published in J.Phys.Soc.Jpn.
Vol.71, No.3 (2002
Remark about string field for general configuration of N D-instantons
In this paper we would like to suggest matrix form of the string field for
any configuration of N D-instantons in bosonic string field theory.Comment: 17 pages, R1:corrected some typos, reference adde
AzTEC/ASTE 1.1-mm Survey of the AKARI Deep Field South: source catalogue and number counts
We present results of a 1.1 mm deep survey of the AKARI Deep Field South
(ADF-S) with AzTEC mounted on the Atacama Submillimetre Telescope Experiment
(ASTE). We obtained a map of 0.25 sq. deg area with an rms noise level of
0.32-0.71 mJy. This is one of the deepest and widest maps thus far at
millimetre and submillimetre wavelengths. We uncovered 198 sources with a
significance of 3.5-15.6 sigma, providing the largest catalog of 1.1 mm sources
in a contiguous region. Most of the sources are not detected in the
far-infrared bands of the AKARI satellite, suggesting that they are mostly at z
~ 1.5 given the detection limits. We constructed differential and cumulative
number counts in the ADF-S, the Subaru/XMM Newton Deep Field (SXDF), and the
SSA 22 field surveyed by AzTEC/ASTE, which provide currently the tightest
constraints on the faint end. The integration of the best-fit number counts in
the ADF-S find that the contribution of 1.1 mm sources with fluxes >=1 mJy to
the cosmic infrared background (CIB) at 1.1 mm is 12-16%, suggesting that the
large fraction of the CIB originates from faint sources of which the number
counts are not yet constrained. We estimate the cosmic star-formation rate
density contributed by 1.1 mm sources with >=1 mJy using the best-fit number
counts in the ADF-S and find that it is lower by about a factor of 5-10
compared to those derived from UV/optically-selected galaxies at z ~ 2-3. The
fraction of stellar mass of the present-day universe produced by 1.1 mm sources
with >=1 mJy at z >= 1 is ~20%, calculated by the time integration of the
star-formation rate density. If we consider the recycled fraction of >0.4,
which is the fraction of materials forming stars returned to the interstellar
medium, the fraction of stellar mass produced by 1.1 mm sources decrease to
<~10%.Comment: 15 pages, 12 figure, accepted for publication in MNRA
Large-scale Oscillation of Structure-Related DNA Sequence Features in Human Chromosome 21
Human chromosome 21 is the only chromosome in human genome that exhibits
oscillation of (G+C)-content of cycle length of hundreds kilobases (500 kb near
the right telomere). We aim at establishing the existence of similar
periodicity in structure-related sequence features in order to relate this
(G+C)% oscillation to other biological phenomena. The following quantities are
shown to oscillate with the same 500kb periodicity in human chromosome 21:
binding energy calculated by two sets of dinucleotide-based thermodynamic
parameters, AA/TT and AAA/TTT bi-/tri-nucleotide density, 5'-TA-3' dinucleotide
density, and signal for 10/11-base periodicity of AA/TT or AAA/TTT. These
intrinsic quantities are related to structural features of the double helix of
DNA molecules, such as base-pair binding, untwisting/unwinding, stiffness, and
a putative tendency for nucleosome formation.Comment: submitted to Physical Review
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