3,948 research outputs found
Nonexistence of self-similar singularities for the 3D incompressible Euler equations
We prove that there exists no self-similar finite time blowing up solution to
the 3D incompressible Euler equations. By similar method we also show
nonexistence of self-similar blowing up solutions to the divergence-free
transport equation in . This result has direct applications to the
density dependent Euler equations, the Boussinesq system, and the
quasi-geostrophic equations, for which we also show nonexistence of
self-similar blowing up solutions.Comment: This version refines the previous one by relaxing the condition of
compact support for the vorticit
Inclusive angular distribution of alpha and Li fragments produced in the Fe-C and Fe-Pb collisions at 1.88 GeV/u
The LS (laboratory system) emission angles theta for 2188 and 298 Li fragments, produced inclusively in relativistic Fe-C and Fe-Pb collisions, have been measured in reference to incident Fe-ion beam tracks nearby in nuclear emulsion. An empirical differential frequency formula, dN(cot theta) = exp (a + b cot theta)d(cot theta) is obtained with the constant b approx. = -0.026 at 1.88 GeV/u, which seems to be independent on the kinds of target nucleus as well as on the kinds of projectile fragments
Magnetic and humidity sensing properties of nanostructured Cu[x]Co[1-x]Fe2O4 synthesized by auto combustion technique
Magnetic nanomaterials (23-43 nm) of CuCoFeO\ (x = 0.0,
0.5 and 1.0) were synthesized by auto combustion method. The crystallite sizes
of these materials were calculated from X-ray diffraction peaks. The band
observed in Fourier transform infrared spectrum near 575 cm in these
samples confirm the presence of ferrite phase. Conductivity measurement shows
the thermal hysteresis and demonstrates the knee points at 475C, 525C
and 500C for copper ferrite, cobalt ferrite and copper-cobalt mixed ferrite
respectively. The hystersis M-H loops for these materials were traced using the
Vibrating Sample Magnetometer (VSM) and indicate a significant increase in the
saturation magnetization (M) and remanence (M) due to the substitution
of Cu ions in cobalt ferrite, while the intrinsic coercivity (H) was
decreasing. Among these ferrites, copper ferrite exhibits highest sensitivity
for humidity.Comment: 12 pages, 7 figure
Discrimination, Attribution, and Racial Group Identification: Implications for Psychological Distress Among Black Americans in the National Survey of American Life (2001–2003)
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112256/1/j.1939-0025.2011.01122.x.pd
Correlated metallic state of vanadium dioxide
The metal-insulator transition and unconventional metallic transport in
vanadium dioxide (VO) are investigated with a combination of spectroscopic
ellipsometry and reflectance measurements. The data indicates that electronic
correlations, not electron-phonon interactions, govern charge dynamics in the
metallic state of VO. This study focuses on the frequency and temperature
dependence of the conductivity in the regime of extremely short mean free path
violating the Ioffe-Regel-Mott limit of metallic transport. The standard
quasiparticle picture of charge conduction is found to be untenable in metallic
VO.Comment: 5 pages, 3 figure
B0850+054: a new gravitational lens system from CLASS
We report the discovery of a new gravitational lens system from the CLASS
survey. Radio observations with the VLA, the WSRT and MERLIN show that the
radio source B0850+054 is comprised of two compact components with identical
spectra, a separation of 0.7 arcsec and a flux density ratio of 6:1. VLBA
observations at 5 GHz reveal structures that are consistent with the
gravitational lens hypothesis. The brighter of the two images is resolved into
a linear string of at least six sub-components whilst the weaker image is
radially stretched towards the lens galaxy. UKIRT K-band imaging detects an
18.7 mag extended object, but the resolution of the observations is not
sufficient to resolve the lensed images and the lens galaxy. Mass modelling has
not been possible with the present data and the acquisition of high-resolution
optical data is a priority for this system.Comment: 5 pages, 4 figures, accepted for publication in MNRA
Mechanisms of transmurally varying myocyte electromechanics in an integrated computational model
The mechanical properties of myocardium vary across the transmural aspect of the left ventricular wall. Some of these functional heterogeneities may be related to differences in excitation–contraction coupling characteristics that have been observed in cells isolated from the epicardial, mid-myocardial and endocardial regions of the left ventricle of many species, including canine. Integrative models of coupled myocyte electromechanics are reviewed and used here to investigate sources of heterogeneous electromechanical behaviour in these cells. The simulations (i) illustrate a previously unrecognized role of the transient outward potassium current in mechanical function and (ii) suggest that there may also exist additional heterogeneities affecting crossbridge cycling rates in cells from different transmural regions
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