6,735 research outputs found
Dependence of shock-tube boundary layers on shock strength
Using familiar considerations of vorticity transport, the essential behavior of shock-tube boundary layers is explicitly exhibited; the nearly constant functions that cannot be calculated analytically are evaluated numerically and compared with Mirels' correlations
Fast computation of MadGraph amplitudes on graphics processing unit (GPU)
Continuing our previous studies on QED and QCD processes, we use the graphics
processing unit (GPU) for fast calculations of helicity amplitudes for general
Standard Model (SM) processes. Additional HEGET codes to handle all SM
interactions are introduced, as well assthe program MG2CUDA that converts
arbitrary MadGraph generated HELAS amplitudess(FORTRAN) into HEGET codes in
CUDA. We test all the codes by comparing amplitudes and cross sections for
multi-jet srocesses at the LHC associated with production of single and double
weak bosonss a top-quark pair, Higgs boson plus a weak boson or a top-quark
pair, and multisle Higgs bosons via weak-boson fusion, where all the heavy
particles are allowes to decay into light quarks and leptons with full spin
correlations. All the helicity amplitudes computed by HEGET are found to agree
with those comsuted by HELAS within the expected numerical accuracy, and the
cross sections obsained by gBASES, a GPU version of the Monte Carlo integration
program, agree wish those obtained by BASES (FORTRAN), as well as those
obtained by MadGraph. The performance of GPU was over a factor of 10 faster
than CPU for all processes except those with the highest number of jets.Comment: 37 pages, 12 figure
Method for producing heat-resistant semi-inorganic compounds
The method for producing a heat resistant, semi-inorganic compound is discussed. Five examples in which various alcohols, phenols, and aromatic carbonic acids are used to test heat resistance and solubility are provided
Organometalic carbosilane polymers containing vanadium and their preparation
The present invention concerns a new organometallic polymer material containing in part a vanadium-siloxane linkage (V-0-Si), which has excellent resistance to heat and oxidation and a high residue ratio after high temperature treatment in a non-oxidizing atmosphere, for example, nitrogen, argon, helium, ammonia, or hydrogen
Magnification effect on the detection of primordial non-Gaussianity from photometric surveys
We present forecast results for constraining the primordial non-Gaussianity
from photometric surveys through a large-scale enhancement of the galaxy
clustering amplitude. In photometric surveys, the distribution of observed
galaxies at high redshifts suffers from the gravitational-lensing
magnification, which systematically alters the number density for
magnitude-limited galaxy samples. We estimate size of the systematic bias in
the best-fit cosmological parameters caused by the magnification effect,
particularly focusing on the primordial non-Gaussianity. For upcoming deep
and/or wide photometric surveys like HSC, DES and LSST, the best-fit value of
the non-Gaussian parameter, fNL, obtained from the galaxy count data is highly
biased, and the true values of fNL would typically go outside the 3-sigma error
of the biased confidence region, if we ignore the magnification effect in the
theoretical template of angular power spectrum. The additional information from
cosmic shear data helps not only to improve the constraint, but also to reduce
the systematic bias. As a result, the size of systematic bias on fNL would
become small enough compared to the expected 1-sigma error for HSC and DES, but
it would be still serious for deep surveys with z_m > 1.5, like LSST.
Tomographic technique improves the constraint on fNL by a factor of 2-3
compared to the one without tomography, but the systematic bias would increase.Comment: 12 pages, 10 figure
Infrared study of valence transition compound YbInCu4 using cleaved surfaces
Optical reflectivity R(w) of YbInCu4 single crystals has been measured across
its first-order valence transition at T_v ~ 42 K, using both polished and
cleaved surfaces. R(w) measured on cleaved surfaces Rc(w) was found much lower
than that on polished surface Rp(w) over the entire infrared region. Upon
cooling through T_v, Rc(w) showed a rapid change over a temperature range of
less than 2 K, and showed only minor changes with further cooling. In contrast,
Rp(w) showed much more gradual and continuous changes across T_v, similarly to
previously reported data on polished surfaces. The present result on cleaved
surfaces demonstrates that the microscopic electronic structures of YbInCu4
observed with infrared spectroscopy indeed undergo a sudden change upon the
valence transition. The gradual temperature-evolution of Rp(w) is most likely
due to the compositional and/or Yb-In site disorders caused by polishing.Comment: 4 pages, 4 figures, Fig.1(a) correcte
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