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 $XXZ$ 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