7,875 research outputs found
Quantum dense coding over Bloch channels
Dynamics of coded information over Bloch channels is investigated for
different values of the channel's parameters. We show that, the suppressing of
the travelling coded information over Bloch channel can be increased by
decreasing the equilibrium absolute value of information carrier and
consequently decreasing the distilled information by eavesdropper. The amount
of decoded information can be improved by increasing the equilibrium values of
the two qubits and decreasing the ratio between longitudinal and transverse
relaxation times. The robustness of coded information in maximum and partial
entangled states is discussed. It is shown that the maximum entangled states
are more robust than the partial entangled state over this type of channels
The Study of the Interac tion between Uranium Monosulphide and Nitrogen
The study of the process of interaction between nitrogen and
nearly stoichiometric uranium monosulphide reveals at least three
distinct stages. The first one (200-580° C) is characterized by limited
interstitial dissolution of nitrogen in th e lattice. At approximately
580° C , US starts to react with N 2 yielding uranium sulphonitride
of the composition U 2S 2Ny. Above 1200° C U2S 2N y decomposes into
US and U 2S2 _ xNy. The X-ray powder diffraction m ethod was used
in order to derive the most probable atomic positions in the crystal
structure of U2S2N
The Crystal Structure of TiCuHg2
X-Ray studies in the ternary system Ti-Cu-Hg revealed the
existence of a new phase of the composition TiCuHg2. The cubic
unit cell has a lattice parameter a = 6.155 A and conta ins appr. 3
formula units. The crystal structure was determined from x-ray
powder diffraction data and found to belong to the ordered B 32
structure type. The density measurements indicate that the structure
is only 710/o filled
The Crystal Structure of TiCuHg2
X-Ray studies in the ternary system Ti-Cu-Hg revealed the
existence of a new phase of the composition TiCuHg2. The cubic
unit cell has a lattice parameter a = 6.155 A and conta ins appr. 3
formula units. The crystal structure was determined from x-ray
powder diffraction data and found to belong to the ordered B 32
structure type. The density measurements indicate that the structure
is only 710/o filled
The Homogeneity Range in the System UP(O)
A large number of samples of uranium monorphosphide were prepared
by direct reaction between uranium filings and red phosphor us, followed by homogenization in a high temperature furnace (Degussa) at 1200-1300 °c and a pres,sure of 10-4 Torr (1 Torr = 101.325/760 kPa). Samples were analyzed for uranium, phosphorus and nitrogen, assuming that the difference is oxygen. The oxygen content wa.s found to vary from sample to sample, ranging from 0.54 (min.) up to 7.10 wt. O/o (max.). X-ray analysis did not indicate the presence
of U02• The amount of oxygen or nitrogen was not controled in advance, but final results ensured the working hypothesis, since the analytical data were in acordance with the X-ray powder diagrams
Magnetic structures of Mn3-xFexSn2: an experimental and theoretical study
We investigate the magnetic structure of Mn3-xFexSn2 using neutron powder
diffraction experiments and electronic structure calculations. These alloys
crystallize in the orthorhombic Ni3Sn2 type of structure (Pnma) and comprise
two inequivalent sites for the transition metal atoms (4c and 8d) and two Sn
sites (4c and 4c). The neutron data show that the substituting Fe atoms
predominantly occupy the 4c transition metal site and carry a lower magnetic
moment than Mn atoms. Four kinds of magnetic structures are encountered as a
function of temperature and composition: two simple ferromagnetic structures
(with the magnetic moments pointing along the b or c axis) and two canted
ferromagnetic arrangements (with the ferromagnetic component pointing along the
b or c axis). Electronic structure calculations results agree well with the
low-temperature experimental magnetic moments and canting angles throughout the
series. Comparisons between collinear and non-collinear computations show that
the canted state is stabilized by a band mechanism through the opening of a
hybridization gap. Synchrotron powder diffraction experiments on Mn3Sn2 reveal
a weak monoclinic distortion at low temperature (90.08 deg at 175 K). This
lowering of symmetry could explain the stabilization of the c-axis canted
ferromagnetic structure, which mixes two orthorhombic magnetic space groups, a
circumstance that would otherwise require unusually large high-order terms in
the spin Hamiltonian.Comment: 11 pages, 13 figure
A Simulation Model Outline for the Hungarian Forest Sector
The model presented in this paper describes the structure of the Hungarian forest sector. The planning of the sector at a national and company level as well as the mechanism of regulation concerning production, investments, and consumption are also investigated and the exports and imports linked.
One of the most important objectives is to create this model in order to study the behavior of the system so as to aid the decision making both in strategic and tactical areas. Apart from forestry the model also includes the wood processing activities
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