Small subgraphs of random regular graphs

The main aim of this short paper is to answer the following question. Given a fixed graph H, for which values of the degree d does a random d-regular graph on n vertices contain a copy of H with probability close to one?     

Experimental investigation of liquid chromatography columns by means of computed tomography

The efficiency of packed chromatographic columns was investigated experimentally by means of computed tomography (CT) techniques. The measurements were carried out by monitoring tracer fronts in situ inside the chromatographic columns. The experimental results were fitted using the equilibrium dispersive model (EDM) and varying the so called apparent axial dispersion coefficient. The additivity of the first and second central moments was exploited to estimate column efficiency in different regions of the column. The results showed that the columns under investigation offered a higher column efficiency in the centre compared to the wall region. Furthermore the void fraction in the vicinity of the walls was lower than that in the column core. For this reason the bands were conveyed faster in the central region of the column where the permeability was higher. This result is in good agreement with earlier findings.     

Nontrivial periodicity in discrete delay models of population growth

In this paper, we will study the periodicity in discrete model An+1=λAn+F(An−m) of population growth, where the delay m is large enough and the nonlinearity F is unimodal function. Actually, we prove that there is a slowly oscillated periodic solution. Our method is Browder nonextremal fixed point theorem.     

Almost-periodic dissipative actions of semigroups

Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 40, No. 1, pp. 110–113, January–February, 1988.     

ДлИны Boлн и Bepoятнocти пeppexoдoв Для иэoэлeктpoннoЙ пocлeдoбaтэльнocти киcлoпoдa

Energies of the transitions 1s²2s²2p⁴?1s²2s2p⁵?1s²2p⁶ belonging to the isoelectronic sequence of oxygen have been calculated. The Hartre-Fock energy and the correlation energy, as well as relativistic corrections, were taken into account. The results have been compared with experimental data. Agreement was found to be good, thus suggesting that the $\text{(}\text{1}\text{Z}\text{)-}\text{expansion}$ converges rapidly. Perturbation theory was used for calculations of transition probabilities for the transitions 1s²2s²2p⁴?1s²2s2p⁵?1s²2p⁶ of the isoelectronic sequence of oxygen. The results may be useful in interpreting soft X-ray line radiation from these transitions, as observed in the solar corona and in high-temperature laboratory-generated plasmas.     

Fission-fragment energy correlation measurements for (nth, f) of 232U and 233U

Fission-fragment mass and kinetic energy distributions and their correlations have been measured for ²³²U and ²³³U. The results on these uranium isotopes and ²³⁵U are compared. The mass peak/valley ratio of 785 ± 68 for ²³²U is the highest of the three isotopes. The 〈E_K〉(μ_H) distributions show significant differences. The dip ΔE_K at symmetry is $\text{16.2 ± 1.0}\text{MeV}\text{(}{}^{232}\text{U}\text{)}$, $\text{17.0 ± 1.0}\text{MeV}\text{(}{}^{233}\text{U}\text{)}\text{and}\text{20.6 ± 1.1}\text{MeV}\text{(}{}^{235}\text{U}\text{)}$. In the yields for high-kinetic-energy-selected events, the mass 134 dominates for ²³³U and ²³⁵U, but for ²³²U it is μ_H≈144, which dominates. This complete reversal of profiles can be understood in terms of fragment shells.