XeI barrier discharge excilamp

Barrier discharges in Xe-I₂ (100-0.04 Torr) mixtures are studied experimentally and theoretically. It is shown that the experimental efficiency and the intensity of radiation in the B → X band of XeI* (253 nm) may reach 5.5% and 9 mW/cm², respectively. The simulation results show that the main energy loss channel is heating of ions. The radiation yield can be increased by shortening the applied voltage pulse duration.     

Structurally nonrigid molecular complexes (HF)n(H2O)m (n + m ≥ 2) and their spectroscopic features

The problem of the formation and stability of structurally nonrigid, donor—acceptor molecular complexes is considered. These complexes are formed between the molecules of water and hydrogen fluoride, the latter being the hydrolysis product of the chemical, radiochemical, and metallurgical industrial wastes. Based on the results of ab initio quantum-chemical calculations of the potential energy surfaces by the Hartree—Fock—Roothaan method, the equilibrium configurations of the (H₂O) _n (HF) _m complexes (n : m = 1 : 1; 1 : 2; 2 : 1; 2 : 2; and 3 : 3) were determined. These configurations are necessary for correct interpretation of the IR absorption spectra and for routine remote monitoring of such environmentally hazardous complexes in the Earth atmosphere. The harmonic vibrational frequencies of the (H₂O) _n (HF) _m complexes (n + m 2) were calculated and the interaction energies between the monomers were found. The influence of UV radiation on the (H₂O) _n (HF) _n complexes (n = 1—3) upon the transition from the ground to the lowest excited singlet electronic state was studied. Characteristic spectroscopic features of the (H₂O) _n (HF) _m complexes were established.     

Photoelectrochemical Behavior of Electrodes Containing One-Walled Carbon Nanotubes

Photoelectrochemistry of electrodes containing single-walled carbon nanotubes is studied for the first time ever. Photoemission of electrons from such electrodes illuminated by UV light is discovered. It is established that the photocurrent amplitude as a function of the imposed potential obeys the 5/2 law and that the work function into solution for nanotubes and a mercury electrode coincide to within 0.08 eV. Similarity of electrochemical behavior of intermediates on the nanocarbon and mercury electrodes is shown with the reduction of radicals CH₂Cl as an example.     

About the nature of Ni3+ magnetic centres in the LaSrAl1−xNixO4 ceramics

LaSrAl_1?x Ni _x 0₄ (x≤0.11) ceramics werer studied by EPR. It was established that Ni³⁺ ions in this compound may be in two states: a low spin one with t _2g ⁶ e _g ¹ electron configuration and high spin state with t _2g ⁵ e _g ² electron configuration. It was shown that the random distribution of La³⁺ and Sr²⁺ ions in the heavy metal sublattice leads to two kinds for each type of these centres with different degree of tetragonal distortions. The total concentration of NiO₆ isolated centres in these ceramics does not exceed 5–10 % of a total number of nickel ions at a givenx. A model, explaining these peculiarities observed in an experiment by the enhanced tendency of Ni³⁺ ions to clusterization, was proposed. It appears that even at small concentrations Ni³⁺ ions form clusters and conglomerates, whose structural characteristics of the oxygen octahedra are comparable with those in LaSrNiO₄.     

Study of the formation and stability of the NdSr<Subscript>2</Subscript>Mn<Subscript>2</Subscript>O<Subscript>7</Subscript> phase

The sequence of phase equilibria during synthesis of the NdSr₂Mn₂O₇ phase is determined. The stability of this phase with changes in temperature and partial oxygen pressure is investigated.     

Some questions of the qualitative theory of nonsmooth Sturm-Liouville problems

Classical oscillation properties (number of zeroes of eigenfunctions and their alteration) of the Sturm-Liouville problem are extended to the case of nonsmooth or discontinuous solutions. Dedicated to Vladimir Alexandrovich Kondratiev, who is Mathematician by the Grace of God __________ Translated from Trudy Seminara imeni I. G. Petrovskogo, No. 26, pp. 254–273, 2007.     

Photography of an Object for Synthesizing a Composite Hologram

The quality of the image recorded on a synthesized hologram with different arrangements of the cameras forming the original images is analyzed. Optimum parameters of the positioning of cameras for forming images recorded on subholograms in order to construct composite holograms with minimum distortions have been obtained.     

Grafting of Methylenebutanedioic Acid to Low-Density Polyethylene in the Course of Reactive Extrusion,Initiated with Carborane-Containing Peroxides

The influence of carborane-containing peroxides on the efficiency of grafting of methylenebutanedioic acid to low-density polyethylene in a single-screw extrusion reactor equipped with a static mixer was studied.