160 research outputs found

    Experimental evidence of strong phonon scattering in isotopical disordered systems: The case of LiH_xD_{1-x} crystals

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    The observation of the local - mode vibration, the two - mode behavior of the LO phonons at large isotope concentration, as well as large line broadening in LIH - D mixed crystals directly evidence strong additional phonon scattering due to the isotope - induced disorder.Comment: 9 pages, 4 figure

    COMPLEX TREATMENT OF ACUTE NONSPECIFIC PLEURAL EMPYEMA

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    In the article the results of complex treatment of acute pleural empyema in 123 patients are presented. In all cases we observed pleural empyema of nontraumatic character. Positive results of treatment of patients with this pathology are marked in patients whose complex of treatment included laser therapy

    EFFICIENCY OF “BALIZ” PREPARATION IN COMPLEX TREATMENT OF ACUTE PLEURAL EMPYEMA

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    The article presents the results of complex treatment of empyema pleuras in 66 patients. In all cases pleural empyema of non-traumatic character was observed. Positive results are marked in patients underwent complex treatment which included intrapleural introduction of preparation «Baliz»

    Paraffin coated rubidium cell with an internal atomic vapor source

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    We present the results of a study on relaxation and diffusion processes of rubidium atoms in a rubidium cell with an internal vapor source. The cell is an evacuated glass bulb, which is characterized in that the source of atomic vapors in the form of a metal film Rb is evenly distributed throughout the inner surface of the bulb, and the paraffin film is uniformly distributed over the entire area and over the metal surface. By using laser optical pumping, we performed measurements of the relaxation time and the average number of bounces of optical pumped rubidium atoms in the bulb. We have measured the adsorption time of rubidium atoms by paraffin coating and rubidium atoms diffusion coefficient in paraffin used. A simple model of the pumping and atomic diffusion processes in the cell is discussed as well.Comment: 10 pages, 6 figure

    TREATMENT OF HIRSCHSPRUNG DISEASE IN ADULTS

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    The article presents our own experience of treatment of Hirschsprung disease in adults

    Lasing on the D_2 line of sodium in helium atmosphere due to optical pumping on the D_1 line (up-conversion)

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    A new method is proposed to produce population inversion on transitions involving the ground state of atoms. The method is realized experimentally with sodium atoms. Lasing at the frequency corresponding to the sodium D_2 line is achieved in the presence of pump radiation resonant to the D_1 line with helium as a buffer gas.Comment: 4 pages, 4 figures, Late

    Spectroscopy of Baryons Containing Two Heavy Quarks in Nonperturbative Quark Dynamics

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    We have studied the three quark systems in an Effective Hamiltonian approach in QCD. With only two parameters: the string tension sigma and the strong coupling constant alpha_s we obtain a good description of the ground state light and heavy baryons. The prediction of masses of the doubly heavy baryons not discovered yet are also given. In particular, a mass of 3620 MeV for the lightest (ccu) baryon is found by employing the hyperspherical formalism to the three quark confining potential with the string junction.Comment: 8 pages, LaTe

    Isotopic Dependence of the Casimir Force

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    We calculate the dependence of the Casimir force on the isotopic composition of the interacting objects. This dependence arises from the subtle influence of the nuclear masses on the electronic properties of the bodies. We discuss the relevance of these results to current experiments utilizing the iso-electronic effect to search at very short separations for new weak forces suggested by various unification theories.Comment: 12 pages, Revtex (to appear in Physical Review Letters

    High-Pressure Structural Systematics in Neodymium to 302 GPa

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    Angle-dispersive x-ray powder diffraction experiments have been performed on neodymium metal to a pressure of 302 GPa. Up to 70 GPa we observe the hP4cF4hR24oI16hP3hP4 → cF4 → hR24 → oI16 → hP3 transition sequence reported previously. At 71(2) GPa we find a transition to a phase which has an orthorhombic structure (oF8) with eight atoms in the unit cell, space group Fddd. This structure is the same as that recently observed in samarium above 93 GPa, and is isostructural with high-pressure structures found in the actinides Am, Cf, and Cm. We see a further phase transition at 98(1) GPa to a phase with the orthorhombic α-U (oC4) structure, which remains stable up to 302 GPa, the highest pressure reached in this study. Electronic structure calculations find the same structural sequence, with calculated transition pressures of 66 and 88 GPa, respectively, for the hP3F8hP3 → F8 and oF8oC4oF8 → oC4 transitions. The calculations further predict that oC4-Nd loses its magnetism at 100 GPa, in agreement with previous experimental results, and it is the accompanying decrease in enthalpy and volume that results in the transition to this phase. Comparison calculations on the oF8 and oC4 phases of Sm show that they both retain their magnetism to at least 240 GPa, with the result that oC4-Sm is calculated to have the lowest enthalpy over a narrow pressure region near 200 GPa at 0 K
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