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We consider a mathematical model of a plane-parallel action of a medium on a rigid body whose surface has a part which is a circular cone. We present a complete system of equations of motion under the quasi-stationarity conditions. The dynamical part of equations of motion form an independent system that possesses an independent second-order subsystem on a two-dimensional cylinder. We obtain an infinite family of phase portraits on the phase cylinder of quasi-velocities corresponding to the presence in the system of only a non-conservative pair of forces., UDC 531.01; 531.552 1. Statement of the problem. Consider a plane-parallel motion of a homogeneous rigid body of mass m with the cone-shaped front part interacting with a flow of [...]

Characteristics of a source of thermal neutrons based on an evacuated NG-400 neutron generator with the maximum flux ([[PHI].sub.f]) 2 x [10.sup.11] neutron/s for 14 MeV neutrons and 2 x [10.sup.9] neutrons/s for 3 meV neutrons have been investigated. The possibilities of its application for neutron activation analysis have been estimated. The distribution, composition, and density ([[phi].sub.T]) values of the thermal neutron flux have been measured in the inner cavity of the moderator using activation detectors. [[phi].sub.T] was 2 x [10.sup.8] and 2 x [10.sup.6] neutrons/[cm.sup.2] s for thermalized neutrons with energies of14 and 3 MeV, respectively. The possibilities of the apparatus have been estimated theoretically and experimentally for the cases of thermalized neutrons of 14 MeV and 3 MeV. Key words: neutron generator, thermal and fast neutrons, activation analysis, gamma spectrometry. DOI: 10.1134/S1061934810120099, Nondestructive control of materials using thermal neutrons is being intensively developed because of the constantly growing requirements for the quality of the materials. Usually, a nuclear reactor is used in [...]

Influence of Zr-substitution on magnetic properties of [([Lu.sub.1 - x][Zr.sub.x]).sub.2][Fe.sub.17] single crystals was investigated. The homogeneity range of [([Lu.sub.1 - x][Zr.sub.x]).sub.2][Fe.sub.17] compounds extends from x = 0 to 0.2, since the compound with a higher Zr content, x = 0.4, was found to be multiphase. In [([Lu.sub.0.8][Zr.sub.0.2]).sub.2][Fe.sub.17], antiferromagnetism present in [Lu.sub.2][Fe.sub.17] compound is totally suppressed upon Zr substitution and ferromagnetism is stabilized in the whole range of magnetic ordering with a considerable increase of magnetic ordering temperature from 274 K in [Lu.sub.2][Fe.sub.17] to 325 K in [([Lu.sub.0.8][Zr.sub.0.2]).sub.2][Fe.sub.17. Successful hydrogenation without estroying the single-crystalline structure of [([Lu.sub.0.8][Zr.sub.0.2]).sub.2][Fe.sub.17] compound was performed, and [([Lu.sub.0.8][Zr.sub.0.2]).sub.2][Fe.sub.17][H.sub.0.48] hydride was obtained. Hydrogenation of [([Lu.sub.0.8][Zr.sub.0.2]).sub.2][Fe.sub.17] resulted in increase of [T.sub.C] from 325 K to 365 K. [([Lu.sub.0.8][Zr.sub.0.2]).sub.2][Fe.sub.17][H.sub.y] (y = 0, 0.48) compounds have an easy-plane type of magnetic anisotropy and possess magnetic moments of 35 [[micro].sub.B]/f.u. in the ground state. Influence of Zr doping and effect of subsequent hydrogenation of the [([Lu.sub.0.8][Zr.sub.0.2]).sub.2][Fe.sub.17] compound on magnetocrystalline anisotropy of [Lu.sub.2][Fe.sub.17] compound was found to be rather weak. Index Terms--Hydrides, intermetallic compounds, substitutions.

A quantum interferometer made of ceramic YBa2Cu3O(7-x) is used to determine the experimental results of some radio-frequency superconducting quantum interference devices (rf-SQUID). The interferometer was used in a low critical current operated condition in the nonhysteric or in the induction mode. The phase shift of the voltage over the tank circuit coupled to the SQUID is simultaneously measured with the amplitude variation. The signal instabilities predicted for the rF SQUID suggest phase detection. The transfer coefficients for the measured flux-to-output signal is increased by the signal instabilities.

Studies of the electrical resistivity and ac magnetic susceptibility of the 5f-metamagnet UCoAI show the presence of strong spin fluctuation effects at temperatures below 30 K. A step-wise rise of residual resistivity and the a prominent Fermi liquid T(super2) term of resistivity is seen as the field is raised through a metamagnetic transition.

U[Cu.sub.3][Al.sub.2] crystallizes in an ordered variant of the hexagonal Ca[Cu.sub.5] structure. By neutron powder-diffraction, the U atoms were found to occupy the 1a sites, while the 2c sites are occupied by Cu atoms only and a random occupation of the 3g sites by the remaining Cu and Al is found. The magnetic susceptibility, measured on a single crystal grown by the Czochralski triarc technique, is found to be maximal within the hexagonal basal plane with a maximum at about 10 K. For fields applied within the basal plane, the magnetization at 4.2 K exhibits a slight S-shape starting slightly below 15 T. No such anomalies are found for fields applied along the c-axis where the magnetic response is found to be much lower. No additional magnetic peaks, which could be related with long-range antiferromagnetic ordering, were detected in the neutron powder-patterns at low temperatures.

Measurements of the Hall effect and magnetoresistance in the [U.sub.0.52][Pt.sub.0.48] compound are reported. The temperature and magnetic field variations of these properties are discussed in terms of a competition between the Kondo effect and magnetism. The analysis of previous magnetic, thermodynamic and transport measurements together with the data obtained here allows us to attribute UPt to dense Kondo systems.

We report on the magnetization of the heavy-fermion superconductor U[Ni.sub.2][Al.sub.3] measured at 1.5 and 4.2 K in magnetic fields up to 35 T. The results indicate in-plane type of magnetocrystalline anisotropy. At both temperatures, almost linear magnetization curves up to the highest field applied are found. In 35 T, we obtained magnetization values of 0.32 [[micro].sub.B]/f.u. at 1.5 K and 0.30 [[micro].sub.B]/f.u. at 4.2 K.

Magnetic and magnetocaloric properties of single crystal [Er.sub.2][([Co.sub.0.4][Fe.sub.0.6]).sub.17] are examined. First order spin reorientation phase transition is observed at 272 K, magnetic easy-axis anisotropy is below this temperature and the easy-plane one above.

The antiferromagnetic state seen in [Lu.sub.2][Fe.sub.17] at elevated temperatures is stabilized down to the ground state in [([Lu.sub.0.8][Ce.sub.0.2]).sub.2][Fe.sub.17] and [Lu.sub.2][Fe.sub.16.5][Ru.sub.0.5]. The pressure and substitution effects are understood in terms of exchange interaction varying with changes in the lattice parameter c for [([Lu.sub.0.8][Ce.sub.0.2]).sub.2][Fe.sub.17], while for [Lu.sub.2][Fe.sub.16.5][Ru.sub.0.5], the change in magnetic structure has occurred due to the weakening of the positive exchange interaction as a result of the reduction in the Fe magnetic moments.

Spin orientation in the single crystal of [Er.sub.2-x][Fe.sub.14+2x][Si.sub.3] is analyzed by using the magnetic measurements and Mossbauer spectroscopy on [super 57]Fe by using the 14.41 keV resonant transition. The discrepancies in the iron hyperfine fields observed at the same temperature for the powder and single crystal sample on the same iron sites are because of the different spin orientations for these two samples caused by different shape anisotropies.

The electronic properties of a single crystalline U[Ni.sub.0.39][Rh.sub.0.61]Al are measured. The results have provided strong evidence for antiferromagnetic ordering at [T.sub.N]

A study was conducted to analyze electrical resistivity measurements for an UNi2Si2 single crystal in the temperature range 4.2 to 140 K. The single crystal was prepared using the Czochralski technique in a tri-arc furnace. A conventional ac four probe technique was utilized to measure electrical resistivity. The anomalies in the temperature and field dependencies of the resistivity were correlated to magnetic phase transitions.