Reactions of massive nuclei for the synthesis of heavy and superheavy nuclei

We study the effect of the entrance channel and the shell structure of reacting massive nuclei on the fusion mechanism and the formation of evaporation residues of heavy and superheavy nuclei. In the framework of the combined dinuclear system concept and advanced statistical model, we analyze the reactions ³²S+¹⁸²W, ⁴⁸Ti+¹⁶⁶Er and ⁶⁰Ni+¹⁵⁴Sm leading to ²¹⁴Th^*, and the reactions ⁴⁸Ca+²⁴⁸Cm and the ⁴⁸Ca+²⁴⁹Cf leading to the ²⁹⁶116 and ²⁹⁷118 compound nuclei, respectively.     

Peculiarities of Adsorption of Some Polar Substances from Vapor Phase on a Microporous Clay Adsorbent

The adsorption of polar organic substances (methanol, pyridine, and acetonitrile) and water was studied from the vapor phase on microporous adsorbent prepared by the substitution of polyhydroxyaluminum ions for the sodium ions of natural montmorillonite clay. The differential isosteric heats of adsorption of these substances were calculated and analyzed in a wide range of fillings.     

Eligibility of spherical-well approximation for calculations of nucleon-transfer matrix elements

Single-particle matrix elements of nucleon transfer were calculated by the Woods-Saxon potential wave functions. The results are compared with the ones calculated by the spherical-well approximation. The eligibility of the approximation of the mean field of nuclei by the spherical well to study the initial stage of nuclear reactions at heavy-ion collisions is demonstrated. The text was submitted by the authors in English.     

The limit distribution of the maximal deviation of a spline estimate of a probability density

One finds the limit distribution of the maximum absolute value of the normalized deviation of a spline estimate from an unknown probability density.Translated from Veroyatnostnye Raspredeleniya i Matematicheskaya Statistika, pp. 447–467, 1986.     

Dynamics of capture and fusion in heavy ion collisions

The effect of entrance channel on decrease of the complete fusion cross sections and on the yield of reaction products are associated with the quasifission which depends on the mass asymmetry and shell structure of colliding nuclei. In reactions of massive projectile and target nuclei, the competition between complete fusion and quasifission appears at the stage of compound nucleus formation, in addition to the increase of the fission probability. It is shown that the yield of quasifission products may be symmetric or asymmetric in dependence on peculiarities of shell structure of reaction fragments. Marima of mass or charge distributions are connected with the peculiarities of shell structure of reaction fragments.     

Adsorption of Carbon Tetrachloride on Pyridinium Montmorillonite

Effect of substitution of Na⁺ by pyridinium on the surface and pore structures of montmorillonite is studied by CCl₄ vapor adsorption.     

A study of fast neutron production in p20Ne and pp interactions at 300 GeV/c

Data on the multiplicity, momentum and angular spectra of fastp _n1 GeV/c) neutrons produced in inelastic interactions of protons with neon nuclei and protons at 300 GeV/c are presented. The experimental results obtained for p²⁰Ne interactions are compared with predictions of the additive quark model in which the intranuclear cascading of slow particles is taken into account.We thank V. G. Grishin and R. J. Loveless for valuable discussions.     

Experimental detection of specular reflection of gamma quanta

Scattering of bremsstrahlung electron beam (E _e = 6.25 MeV) collimated with a vertical divergence δ_γ ≈ ±60 μrad and incident on the mercury surface at glancing angles α = −37, −83, and −140 μrad is studied on the 118-m-long path length. The specular reflection effect is detected in the spectral and angular distributions of γ quanta with energies up to 3 MeV. The reflection coefficients vary from 0 to ∼17% depending on the angles of incidence and the γ quanta energy.     

Features of the precipitation of pectin substances from the valves ofGossypium hirsutum

An effective agent for precipitating pectin substances from the valves of cotton bolls has been selected.Bukhara Technological Institute of the Food and Light Industries. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 202–206, March–April, 1997.     

A Hunziker-van Winter-Zhislin theorem for a four-particle lattice Schrödinger operator

We consider a discrete Schrödinger operator for four arbitrary particles with short-range pair potentials. We describe the position and the structure of its essential spectrum and prove the Hunziker-van Winter-Zhislin theorem.