29,409 research outputs found
Plasma-sprayed self-lubricating coatings
One of the most important criterion for acceptable commercial application of a multiple phase composition is uniformity and reproducibility. This means that the performance characteristics of the coat - e.g., its lubricating properties, bond strength to the substrate, and thermal properties - can be readily predicted to give a desired performance. The improvement of uniformity and reproducibility of the coats, the oxidation behavior at three temperature ranges, the effect of bond coat and the effect of preheat treatment as measured by adhesive strength tests, coating examination procedures, and physical property measurements were studied. The following modifications improved the uniformity and reproducibility: (1) changes and closer control in the particle size range of the raw materials used, (2) increasing the binder content from 3.2% to 4.1% (dried weight), and (3) analytical processing procedures using step by step checking to assure consistency
Infrared behavior of the Faddeev-Popov operator in Coulomb gauge QCD
We calculate the eigenvalue distribution of the Faddeev-Popov operator in
Coulomb gauge QCD using quenched SU(3) lattice simulation. In the confinement
phase, the density of the low-lying eigenvalues increases with lattice volume,
and the confinement criterion is satisfied. Moreover, even in the deconfinement
phase, the behavior of the FP eigenvalue density is qualitatively the same as
in the confinement phase. This is consistent with the fact that the
color-Coulomb potential is not screened in the deconfined phase.Comment: 10 pages, 10 figure
Scaling study of the gluon propagator in Coulomb gauge QCD on isotropic and anisotropic lattices
We calculate the transverse and time-time components of the instantaneous
gluon propagator in Coulomb gauge QCD by using an SU(3) quenched lattice
simulation on isotropic and anisotropic lattices. We find that the gluon
propagators suffer from strong discretization effects on the isotropic lattice;
on the other hand, those on the anisotropic lattices give a better scaling.
Moreover, on these two type of lattices the transverse parts are significantly
suppressed in the infrared region and have a turnover at about 500 [MeV]. The
high resolution to the temporal direction due to the anisotropy yields small
discretization errors for the time-time gluon propagators, which also show an
infrared enhancement as expected in the Gribov-Zwanziger confinement scenario.Comment: 29 pages, 18 figure
Properties of Color-Coulomb String Tension
We study the properties of the color-Coulomb string tension obtained from the
instantaneous part of gluon propagators in Coulomb gauge using quenched SU(3)
lattice simulation.
In the confinement phase, the dependence of the color-Coulomb string tension
on the QCD coupling constant is smaller than that of the Wilson loop string
tension. On the other hand, in the deconfinement phase, the color-Coulomb
string tension does not vanish even for , the temperature
dependence of which is comparable with the magnetic scaling, dominating the
high temperature QCD. Thus, the color-Coulomb string tension is not an order
parameter of QGP phase transition.Comment: 17 pages, 5 figures; one new figure added, typos corrected, version
to appear in PR
Novel Orbital Ordering induced by Anisotropic Stress in a Manganite Thin Film
We performed resonant and nonresonant x-ray diffraction studies of a
Nd0.5Sr0.5MnO3 thin film that exhibits a clear first-order transition. Lattice
parameters vary drastically at the metal-insulator transition at 170K (=T_MI),
and superlattice reflections appear below 140K (=T_CO). The electronic
structure between T_MI and T_CO is identified as A-type antiferromagnetic with
the d_{x2-y2} ferroorbital ordering. Below T_CO, a new type of antiferroorbital
ordering emerges. The accommodation of the large lattice distortion at the
first-order phase transition and the appearance of the novel orbital ordering
are brought about by the anisotropy in the substrate, a new parameter for the
phase control.Comment: 4pages, 4figure
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