Calculation of the adsorption of rod-like molecules in narrow slit-shaped pores

The adsorption of rod-like molecules in slit-shaped pores was considered within the frame-work of the lattice-gas model. This model is applicable over a broad range of fluid concentrations (from the gaseous to the liquid state) and temperatures (including the critical region). In the calculation of the local distributions of mixture components in the equilibrium states, lateral interactions are taken into account. The equations of the model reflect the strong anisotropy of the distribution of mixture components along the normal to the pore wall surface and ordering of the rods along various directions. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1476–1484, September, 2006.     

Random pining of localized states and the birth of deterministic disorder within gradient models

The birth of spatial disorder from almost regular initial conditions within the Swift-Hohenberg model equation with subcritical bifurcation is considered. The complexity of the space series (measured by the spatialK ₂-entropy) grows with time and reaches a stationary value depending on the period of the initial regular disturbance. A qualitative model is suggested describing the process via the birth of localized structures and its subsequent disordering due to weak interaction.     

Gravitational-to-electromagnetic wave conversion in electrostatic field of earth-ionosphere resonator

The conversion of a plane gravitational wave into electromagnetic radiation in the presence of the fair-weather static electric field of the earth-ionosphere resonator is examined. The spatial and frequency characteristics of the induced electromagnetic field of the earth-ionosphere cavity are studied in the range of Schumann resonance frequencies (f=10–100 Hz). Numerical estimates are obtained for the amplitudes of the electromagnetic fields, and the possibilities of a natural gravitational-wave detector are considered.Radio-Astronomy Institute, Academy of Sciences of Ukraine. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 35, No. 6/7, pp. 488–497, June–July, 1992.     

Adhesion between Nanoscale Rough Surfaces

In this investigation, the adhesion between particles and plates with root-mean-square, rms, surface roughness of 0.17-10.5 nm was measured by atomic force microscopy. Measurements obtained with particles both larger and smaller than the surface asperities are presented. Results indicate adhesion force decreases sharply with increasing surface roughness in the nanometer scale (<2 nm), followed by a gradual and slow decrease with further increase in roughness. Existing models were found to significantly underestimate adhesion force. Hence, a new model based on a geometry that considers both the height and breadth of asperities yielding an increased asperity radius compared to previous approaches, as detailed in Part I of this series, is applied using both van der Waals and elastic deformation/work of adhesion based approaches. For the system studied in this investigation, the adhesion forces predicted by the proposed model are considerably more accurate than those predicted by past models. Copyright 2000 Academic Press.     

Self-pulsing and bichromatic emission in homogeneously broadened bidirectional ring lasers

We study the effects of saturation-induced Bragg gratings on the mode structure and dynamics of bidirectional homogeneously broadened ring lasers. The grating is viewed as a distributed feedback medium in a ring cavity and modes appropriate to such a structure are used. A Fourier decomposed rate equation model is developed to study the behavior of these modes above threshold. The difference in the properties of these solutions from the modes of an unfilled ring cavity lead to the possibility of bichromatic emission and both regular undamped and irregular damped self-pulsing.     

Correlation between the equilibrium modulus of high elasticity and the number of crosslinks in rigid crosslinked polymers

A study has been made of the temperature dependence of the equilibrium modulus of high elasticity of dimethacrylate-poly(butanediol-1,4-phthalates).Mekhanika Polimerov, Vol. 2, No. 1, pp. 3–6, 1966     

Examination of intramolecular potential surfaces of flexible conjugated molecules by calculation of crystal structures. equilibrium geometries of chalc

A method for refinement of intramolecular potential surfaces of flexible molecules is proposed based on the knowledge of the equilibrium molecular geometry in the crystal and on a good first approximation to the intra- and intermolecular surfaces. The equilibrium conformation in the crystal is calculated by minimization of the total potential with respect to all Cartesian coordinates of the asymmetric unit as well as the components of the unit cell parameters. The initial approximations to the potential function are further refined with the purpose of obtaining better agreement between the calculated crystal equilibrium geometry and the corresponding X-ray results. The previously proposed QCFF/PI potential surfaces for conjugated hydrocarbons are re-examined by calculation of the crystal structures of chalcone, p-methylchalcone, p,p'-dimethylchalcone and α,ω-diphenyloctatetraene. The resulting potentials of the present refinement are somewhat shallower than the previous QCFF/PI surfaces. It is suggested that the application of the method as a model calculation may be considered a reliable “quasi-experimental” technique for the determination of gas phase equilibrium conformations.