Energy spectra and temperature distributions of clusters produced during ion-beam sputtering of metals

A method for evaluating the energy spectra and temperature dependences of the yield of neutral and charged clusters that consist of N≥5 atoms and are produced by ion bombardment of metals is proposed. The results are presented in the form of simple formulas. Theoretical energy spectra of clusters emitted as a result of bombarding niobium, tantalum, and iron targets by atomic ions of gold or xenon and temperature dependences of the yield of silver clusters produced by bombarding the targets with xenon ions are compared with experimental data.

     

Direct Single-Stage Conversion of Synthesis Gas to Dimethoxymethane: Influence of the Sequence of Metal Introduction into Cu, Pd-Zeolite Catalysts on the Degree of Cu and Pd Reduction and Catalyst Acidity

The influence of the sequence of Cu and Pd introduction into zeolite matrice when preparing Cu, Pd-zeolite catalysts on their acidity and degree of metal reduction was studied. The mutual influence of Cu and Pd on their reducibility was analyzed. The selectivity of Cu, Pd-zeolite catalysts in conversion of synthesis gas to different products was elucidated.     

Focusing effect of periodic gravitational waves

A study is made of the focusing of test particles and light rays in the field of periodic plane gravitational waves described by exact solutions of the Einstein equations. The periodicity of the focusing is investigated as a function of the type of polarization of the gravitational wave, its frequency, and intensity. The magnitude of the effect is estimated for the gravitational radiation of a pulsar.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 120–125, September, 1978.     

Relativistic four-quark equations and exotic mesons

The relativistic four-quark equations are found in the framework of the dispersion relation technique. The behaviour of the low-energy four-particle amplitude is determined by its leading singularities in the pair invariant masses. The approximate solutions of these equations using the method based on the extraction of leading singularities of the amplitudes are obtained. The mass values of lowest exotic mesons are calculated.     

Cosmological constant,scalar field,and the coincidence problem

Theoretical and Mathematical Physics - We study a phenomenological model in which dark matter in the cosmological constant form is identified with the mean energy–momentum tensor of a...     

Differential elastic moduli of an anisotropic medium under pressure

Natural strain theory is used to determine the tensor of the differential elastic moduli for strains of arbitrary magnitude and its relationship is established with values measured in acoustic and mechanostatic experiments in which an additional small load is applied. For illustration purposes an expression for this tensor is given for an object which is isotropic before application of the load, and formulas to determine this tensor from the results of measurements are calculated for an anisotropic object under pressure to within the second order in terms of the shear produced as a result of its hydrostatic compression.     

Resonances and near-threshold scattering in 3,4Hedμ

Elastic and inelastic scattering cross-sections in the ^3,4Hedμ systems near the dμ threshold are calculated. The isotopic effect and strong energy dependence in ⁴Hedμ are found. The reason for these peculiarities is the near-threshold pole of the ⁴Hedμ scattering amplitude. This revised version was published online in August 2006 with corrections to the Cover Date.