1,272 research outputs found
Research, development and application of the innovational technology of high quality pump-compressor pipes production from sections
The innovational technology of high-strength, cold- and corrosion-resistant pump-compressor pipes from sections was developed. It includes the reduction process inside three-high stand of screw rolling before piercing in the «80» pipe-rolling mill line in OAO SinTZ. The special attention is paid to the questions of fine-grained steel production and final tubes quality. It is shown that new technology is efficient from the point of tube production of high level mechanical properties
Massive liquid Ar and Xe detectors for direct Dark Matter searches
A novel experiment for direct searches of the Dark Matter with liquid argon
double-phase chamber with a mass of liquid Ar up to several hundred tons is
proposed. To suppress the b-, g- and n0- backgrounds, the comparison of
scintillation and ionization signals for every event is suggested. The addition
in liquid Ar of photosensitive Ge(CH3)4 or C2H4 and suppression of triplet
component of scintillation signals ensures the detection of scintillation
signals with high efficiency and provides a complete suppression of the
electron background. For the detection of photoelectrons and ionization
electrons, highly stable and reliable GEM detectors must be used.Comment: 8 pages, 2 figures, 1 tabl
The anisotropic Heisenberg model in a transverse magnetic field
One dimensional spin-1/2 model in a transverse magnetic field is
studied. It is shown that the field induces the gap in the spectrum of the
model with easy-plain anisotropy. Using conformal invariance the field
dependence of the gap at small fields is found. The ground state phase diagram
is obtained. It contains four phases with different types of the long range
order (LRO) and a disordered one. These phases are separated by critical lines,
where the gap and the long range order vanish. Using scaling estimations and a
mean-field approach as well as numerical calculations in the vicinity of all
critical lines we found the critical exponents of the gap and the LRO. It is
shown that transition line between the ordered and disordered phases belongs to
the universality class of the transverse Ising model.Comment: 10 pages, 3 figures, LaTe
Are there stable long-range ordered Fe(1-x)Cr(x) compounds?
The heat of formation of Fe-Cr alloys undergoes an anomalous change of sign
at small Cr concentrations. This observation raises the question whether there
are intermetallic phases present in this composition range. Here we report the
discovery of several long-range ordered structures that represent ground state
phases at zero Kelvin. In particular we have identified a structure at 3.7% Cr
with an embedding energy which is 49 meV/Cr atom below the solid solution. This
implies there is an effective long-range attractive interaction between Cr
atoms. We propose that the structures found in this study complete the low
temperature-low Cr region of the phase diagram.Comment: 3 pages, 2 figure
Voltage-Controlled Surface Magnetization of Itinerant Ferromagnet Ni_(1-x)Cu_x
We argue that surface magnetization of a metallic ferromagnet can be turned
on and off isothermally by an applied voltage. For this, the material's
electron subsystem must be close enough to the boundary between para- and
ferromagnetic regions on the electron density scale. For the 3d series, the
boundary is between Ni and Cu, which makes their alloy a primary candidate.
Using Ginzburg-Landau functional, which we build from Ni_(1-x)Cu_x empirical
properties, ab-initio parameters of Ni and Cu, and orbital-free LSDA, we show
that the proposed effect is experimentally observable.Comment: 4 pages; 2 figures; submitted to PRL February 16th 2008; transferred
to PRB June 21st 2008; published July 15th 200
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