Solvent effects in the fluorination of 1,2-dichloro-1,1-difluoroethane (R-132b) to 2-chloro-1,1,1-trifluoroethane (R-133a)

Trichloroethylene has been found to act as a rate enhancing co-factor in the liquid phase, tantalum (V) halide catalyzed, fluorine-for-chlorine exchange reaction of 1,2-dichloro-1,1-difluoroethane (R-132b) to 2-chloro-1,1,1-trifluorethane (R-133a). Several trifluoromethyl substituted benzenes have also been found to be rate-enhancing solvents.     

Enlarged symmetry groups of finite-size clusters with periodic noundary conditions

Any system that approximates an infinite lattice by a family of finite clusters (with periodic boundary conditions) passes through an intermediate region with enlarged (hidden) symmetry as the system size is increased. The hidden symmetry allows for extra degeneracies and level crossings and has application to exact-diagonalization studies, Monte Carlo simulations, lattice gauge theories, and renormalization group calculations.     

Band structures in73Se

Excited states of⁷³Se have been investigated up to spin, 21/2 using techniques of in-beamγ-ray spectroscopy in connection with the⁷⁰Ge(α, n) reaction. Mean lifetimes of 12 levels have been determined applying Doppler-shift andγ-RF-methods. Five different bands have been identified that reflect a variety of different excitation modes. The decoupled 9/2⁺ band is likely to correspond to an oblate deformation while the 5/2⁺ band is interpreted as a strongly coupled prolate band built on the Nilsson configuration [422] 5/2⁺. The 3/2^? band is a strongly coupled band built on the [301] 3/2^} configuration.Nuclear reactions:⁷⁰Ge(α,n),E=14, 16, 18, 19, 20MeV; measuredE _γ,I _γ,σ(E _γ,θ),γγ-coin, linear polarization, DSA,γ(t).⁷⁵Se deduced levels,I, π, τ, δ(E2/M1), B(σλ). Enriched targets, Ge detectors.     

Efficacy of the accent method of voice therapy

The management of voice disorders may follow one of four approaches: surgical, pharmacological, technical aid, and/or voice therapy. The latter approach offers a wide variety of techniques, each based on certain theoretical beliefs. One of these techniques is the Smith Accent Method. The principles and goals of the Accent Method are presented. The results of its application are discussed. This technique proved effective for cases of functional voice disorders, vocal nodules, and some degrees of vocal fold paralysis.