Comments on the correlations between geometric parameters of molecules and parameters of their 1H NMR spectra: The answer to a criticism

An earlier paper by the authors has undergone criticism by Jankowski and Rabczenko. The arguments presented are analysed in this paper and the criticism is rejected.     

Filtration of live oil in the presence of phase transitions in a porous medium with inhomogeneous permeability

The radial angular temperature distribution in a porous medium with inhomogeneous permeability is investigated by numerical simulation of nonisothermal filtration of live oil taking into account the degassing heat, the Joule–Thomson effect, and the adiabatic effect. It is shown that inhomogeneous permeability in the near-wellbore zone of a porous reservoir leads to anomalous cooling due to rapid degassing in the highly permeable region.     

Radial angular temperature distributions for nonisothermal two-phase filtration of oil and water

The distributions of phase saturations, pressure, and temperature in a porous medium of nonuniform permeability are studied by numerical modeling of nonisothermal two-phase filtration of oil and water with the Joule-Thomson effect and adiabatic effect taken into account. It is shown that the presence of nonuniformity in the near-well zone of the reservoir results in nonmonotonic angular and radial distributions of temperature and phase saturations. During oil and water filtration, there is transition from negative to positive temperature anomalies or vice versa, depending on the ratio of the reservoir permeabilities and the presence of a segment on which the angular temperature distribution in the well is nonuniform. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 49, No. 6, pp. 124–130, November–December, 2008.     

Polynomial birth–death processes and the second conjecture of Valent

The conjecture of Valent about the type of Jacobi matrices with polynomially growing weights is proved.     

Electronic Properties of 3<Emphasis Type="Italic">d</Emphasis>-Metal-Doped Zirconia Nanotubes

The electronic structure of hexagonal ZrO₂ nanotubes doped by 3d-metal atoms was calculated by the linearized augmented cylindrical wave (LACW) method. The calculated densities of electronic states indicate that partial substitutions of zirconium atoms by transition metals (Sc, Ti, Mn, Co, and Zn) decrease the optical gap of (4,4) ZrO₂ nanotubes from 3.7 to 2–2.3 eV. Doping of nanotubes shifts optical absorption from the UV to the visible, and the nanotubes themselves become candidate materials for design of electrodes for electrochemical water photolysis.     

Reaction of cholesterol with acetylated alkyl orthoacetates of D-glucopyranose

Summary The condensation of acetylated alkyl orthoacetates of D-glucose with cholesterol has been studied. It has been shown that either transesterification or glycosylation may take place, according to the reaction conditions. Conditions have been found under which the sole direction of the reaction is glycosylation, leading to the 1, 2-trans-glycoside. A standard method for glycosylating complex alcohols with sugar orthoesters has been proposed.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 1, pp. 6–12, 1966