Markov chain model of mixed surfactant systems

A new model of mixed surfactant systems have been developed in the work presented. It includes two parameters only connected directly with the Gibbs free energy of the surfactant aggregation. They can be determined using both the aggregation equilibrium constant values or the phase composition data. It has been shown also the relation between these new parameters and the same of the regular solution approximation and the alternative models. The possibility to describe the available experimental information about the micelle composition as a function of the singly dispersed surfactant mixture composition better than by the other models has been shown also.     

2-D absolute OH concentration profiles in atmospheric flames using planar LIF in a bi-directional laser beam configuration

1 (6) rotational line in the A²Σ⁺(v^′=0)←X²Π(v^′′=0) band of OH at 309 nm. The requirements for obtaining a good signal-to-noise ratio for the technique are discussed and the possibilities of single-shot measurements are investigated. Received: 31 October 1996/Revised version: 3 December 1996     

Isomeric states in180Os

Two new isomers have been observed in¹⁸⁰Os. A high-K isomer withI, K ≧20 and a half-life ofT _1/2=12+4 ns have been established. It deexcites via two transitions into the 18⁺ level of the yrare band indicating an unusually smallK-hindrance factor. Evidence for an isomer withI, K>16 and a half-life ofT _1/2=41±10 ns was found. A half-life of 17±3 ns was measured for the previously known 7^? state at 1862 keV. The decay scheme of the previously known 7^? isomer at 1928 keV has been extended and a revised version is presented.     

Inelastic proton scattering from deformed nuclei: (II). Results with a local approximation

We describe an approximate method of including exchange effects in proton inelastic scattering appropriate to situations where a coupled channel approach is essential, i.e. deformed nuclei. We demonstrate that in this approach the effects of exchange are not large, contrary to what is often said, provided consistence between elastic and inelastic scattering is maintained. The corrections may be roughly represented as a “shifted” zero range approximation which can be viewed as giving a rather smallL-dependent effect. The effect on the extraction of quadrupole moments should not exceed 4% and of hexadecapole moments 10% except at the lowest energies.     

Parametric Borwein-Preiss variational principle and applications

A parametric version of the Borwein-Preiss smooth variational principle is presented, which states that under suitable assumptions on a given convex function depending on a parameter, the minimum point of a smooth convex perturbation of it depends continuously on the parameter. Some applications are given: existence of a Nash equilibrium and a solution of a variational inequality for a system of partially convex functions, perturbed by arbitrarily small smooth convex perturbations when one of the functions has a non-compact domain; a parametric version of the Kuhn-Tucker theorem which contains a parametric smooth variational principle with constraints; existence of a continuous selection of a subdifferential mapping depending on a parameter.

The tool for proving this parametric smooth variational principle is a useful lemma about continuous -minimizers of quasi-convex functions depending on a parameter, which has independent interest since it allows direct proofs of Ky Fan's minimax inequality, minimax equalities for quasi-convex functions, Sion's minimax theorem, etc.

     

Mechanism of alternating copolymerization of polar and hydrocarbon polymers

Radical copolymerization of butyl methacrylate with 2,3-dimethylbutadiene in the presence of Al(C₂H₅)₂Cl or ZnCl₂ results in alternating copolymers. The nature of active centers and the mechanism of polymerization in these systems have been studied by means of ESR measurements in combination with calorimetry at low temperatures. The active centers are monoradicals propagating by alternative addition of single monomer molecules; thus the reaction can be described in terms of a conventional kinetic scheme of radical additional polymerization. Participation of binary donor—acceptor complexes of the monomers in the reaction has not been confirmed. Similar conclusions have been drawn for the other alternating system studied, maleic anhydride–2,3-dimethylbutadiene. The feasibility of formation of alternating copolymers in the studied systems by the conventional mechanism of binary radical copolymerization has been confirmed by qualitative quantum-chemical treatment of the propagation reactions with due account to the donor–acceptor interactions in the transition state.     

Design, Synthesis and pH Sensing Properties of Novel PAMAM Light-Harvesting Dendrons Based on Rhodamine 6G and 1,8-naphthalimide

Herein we report on the design, divergent synthesis and photophysical behavior of novel PAMAM light-harvesting dendrons from first and second generation. The surface of novel compounds is labeled with 4-alkylamino-1,8-naphthalimide yellow-green emitting “donor” fluorophores capable of absorbing light and efficiently transferring the energy to a single rhodamine “acceptor” dye. Due to the pH dependent rhodamine absorption the novel systems show “off-on” switching energy transfer mechanism from alkaline to acid media. The results obtained illustrate the high potential of the synthesized wavelength-shifting fluorophores as efficient pH chemosensing materials.