6,070 research outputs found
Integrable Hierarchies and Contact Terms in u-plane Integrals of Topologically Twisted Supersymmetric Gauge Theories
The -plane integrals of topologically twisted supersymmetric gauge
theories generally contain contact terms of nonlocal topological observables.
This paper proposes an interpretation of these contact terms from the point of
view of integrable hierarchies and their Whitham deformations. This is inspired
by Mari\~no and Moore's remark that the blowup formula of the -plane
integral contains a piece that can be interpreted as a single-time tau function
of an integrable hierarchy. This single-time tau function can be extended to a
multi-time version without spoiling the modular invariance of the blowup
formula. The multi-time tau function is comprised of a Gaussian factor
and a theta function. The time variables play the
role of physical coupling constants of 2-observables carried by the
exceptional divisor . The coefficients of the Gaussian part are
identified to be the contact terms of these 2-observables. This identification
is further examined in the language of Whitham equations. All relevant
quantities are written in the form of derivatives of the prepotential.Comment: latex, 17 pages, no figures; final version for publicatio
Anomalous increase of solar anisotropy above 150GV in 1981-1983
An analysis was carried out of the observed data with Nagoya (surface). Misato (34mwe) and Sakashita (80mwe) multidirectional muon telescope, for the solar activity maximum period of 1978-1983. These data respond to primaries extending over the median rigidity range 60GV to 600GV. The observed amplitude at Sakashita station in 1981-1983 increased, especially in 1982; the amplitude is twice as large as that in 1978-1980, when those at Nagoya and Misato stations are nearly the same as those in 1978-1980. Uni-directional anisotropy is derived by the best fit method by assuming the flat rigidity spectrum with the upper cutoff rigidity Pu. The value of Pu obtained is 270GV in 1981-1983 and 150GV in 1978-1980
Solar tri-diurnal variation of cosmic rays in a wide range of rigidity
Solar tri-diurnal variations of cosmic rays have been analyzed in a wide range of rigidity, using data from neutron monitors, and the surface and underground muon telescopes for the period 1978-1983. The rigidity spectrum of the anisotropy in space is assumed to be of power-exponential type as (P/gamma P sub o) to the gamma exp (gamma-P/P sub o). By means of the best-fit method between the observed and the expected variations, it is obtained that the spectrum has a peak at P (=gamma P sub o) approx = 90 GV, where gamma=approx 3.0 and P sub o approx. 30 GV. The phase in space of the tri-diurnal variation is also obtained as 7.0 hr (15 hr and 23 hr LT), which is quite different from that of approx. 1 hr. arising from the axisymmetric distribution of cosmic rays with respect to the IMF
Field Effect Transistor Based on KTaO3 Perovskite
An n-channel accumulation-type field effect transistor (FET) has been
fabricated utilizing a KTaO3 single crystal as an active element and a
sputtered amorphous Al2O3 film as a gate insulator. The device demonstrated an
ON/OFF ratio of 10^4 and a field effect mobility of 0.4cm^2/Vs at room
temperature, both of which are much better than those of the SrTiO3 FETs
reported previously. The field effect mobility was almost temperature
independent down to 200K. Our results indicate that the Al2O3 / KTaO3 interface
is worthy of further investigations as an alternative system of future oxide
electronics.Comment: 3 pages, 3 Postscript figures, submitted to Appl.Phys.Let
Field-Effect Transistor on SrTiO3 with sputtered Al2O3 Gate Insulator
A field-effect transistor that employs a perovskite-type SrTiO3 single
crystal as the semiconducting channel is revealed to function as n-type
accumulation-mode device with characteristics similar to that of organic FET's.
The device was fabricated at room temperature by sputter-deposition of
amorphous Al2O3 films as a gate insulator on the SrTiO3 substrate. The
field-effect(FE) mobility is 0.1cm2/Vs and on-off ratio exceeds 100 at room
temperature. The temperature dependence of the FE mobility down to 2K shows a
thermal-activation-type behavior with an activation energy of 0.6eV
Ordered phase and scaling in models and the three-state antiferromagnetic Potts model in three dimensions
Based on a Renormalization-Group picture of symmetric models in three
dimensions, we derive a scaling law for the order parameter in the
ordered phase. An existing Monte Carlo calculation on the three-state
antiferromagnetic Potts model, which has the effective symmetry, is shown
to be consistent with the proposed scaling law. It strongly supports the
Renormalization-Group picture that there is a single massive ordered phase,
although an apparently rotationally symmetric region in the intermediate
temperature was observed numerically.Comment: 5 pages in REVTEX, 2 PostScript figure
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Total temperature measurements of laminar gas flow at micro-tube outlet: Cooled from the wall
This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.This paper presents experimental results on heat transfer characteristics of laminar gas flow in a micro-tube with constant wall temperature whose wall temperature is lower than the inlet temperature (cooled case). The experiment was performed for nitrogen gas flow through micro-tubes with 163 and 243
μm in diameter and 50 mm in length. The gas was heated in an upstream section of the micro-tube to Tin=315K, 335K and 355K. The wall temperature was maintained at 305K by circulating water around the micro-tube. The stagnation pressure was chosen in such a way that the exit Mach number ranges from 0.1
to 0.7. The outlet pressure was fixed at the atmospheric condition. The total temperature at the outlet, the inlet stagnation temperature, the mass flow rate and the inlet temperature were measured. The numerical computations based on the Arbitrary – Lagrangian – Eulerian (ALE) method were also performed for the same conditions of the experiment for validation of numerical results. The both results are in excellent agreement. The total and bulk temperatures obtained by the present study are also compared with the temperature of the incompressible flow
ON THE LOW-TEMPERATURE ORDERING OF THE 3D ATIFERROMAGNETIC THREE-STATE POTTS MODEL
The antiferromagnetic three-state Potts model on the simple-cubic lattice is
studied using Monte Carlo simulations. The ordering in a medium temperature
range below the critical point is investigated in detail. Two different regimes
have been observed: The so-called broken sublattice-symmetry phase dominates at
sufficiently low temperatures, while the phase just below the critical point is
characterized by an effectively continuous order parameter and by a fully
restored rotational symmetry. However, the later phase is not the
permutationally sublattice symmetric phase recently predicted by the cluster
variation method.Comment: 20 pages with 9 figures in a single postscript file (compressed and
uuencoded by uufiles -gz -9) plus two big figures in postscript file
Hard X-ray Luminosities of Multinuclei Infrared Luminous Galaxies Showing a Radio/Far-Infrared Excess
We report the results of hard X-ray observations of four multinuclei merging
infrared luminous galaxies (IRLGs). We selected these four sources for their
excess of radio to far-infrared luminosity ratio compared with starburst
galaxies. This excess suggests that activity associated with a supermassive
black hole (SMBH) contributes strongly to the IRLGs' bolometric luminosities.
Although we expect strong hard X-ray emission from the SMBH-driven activity,
the radio-excess multinuclei merging IRLGs show considerably smaller hard X-ray
luminosities relative to far-infrared (40500 m) and infrared (81000
m) luminosities than active galactic nuclei (AGNs) showing a similar
radio-excess. This result may demonstrate that emission in the hard X-ray
region from SMBH-driven activity in the multinuclei merging IRLGs is severely
suppressed compared to a typical spectral energy distribution of SMBH-driven
activity in AGNs. If this is a common property of merging IRLGs, without its
correction, hard X-ray observations underestimate the contribution of
SMBH-driven activity to the bolometric luminosities of merging IRLGs.Comment: 25 pages of text, 4 figures, aaspp4.sty, Astrophysical Journal, in
press (1999, Volume 527
A class of integrable lattices and KP hierarchy
We introduce a class of integrable -field first-order lattices together
with corresponding Lax equations. These lattices may be represented as
consistency condition for auxiliary linear systems defined on sequences of
formal dressing operators. This construction provides simple way to build
lattice Miura transformations between one-field lattice and -field () ones. We show that the lattices pertained to above class is in some sense
compatible with KP flows and define the chains of constrained KP Lax operators.Comment: LaTeX, 13 pages, accepted for publication in J. Phys. A: Math. Ge
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