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A differential calculus on the quantum groupSU q (2) comparible with the gauge-transformation structure

We consider a three-dimensional bicovariant differential calculus on the quantum group SU_q(2) that is compatible with the structure of gauge transformations. In the approach based on the global covariance with respect to the stability subgroup U(1), we show that the gauge-covariant exterior differential algebra on SU_q(2) is uniquely determined. We construct explicit representations of q-deformed Lie algebras in terms of differential operators. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 116, No. 2, pp. 265–276, August. 1998.     

Kinetics of the reactions of the IO radical with dimethyl sulfide,methanethiol, ethylene,and propylene

The reactions of IO radicals with CH₃SCH₃, CH₃SH, C₂H₄, and C₃H₆ have been studied using the discharge flow method with direct detection of IO radicals by mass spectrometry. The absolute rate constants obtained at 298 K are the following: IO + CH₃SCH₃ → products (1): k₁ = (1.5 ± 0.2) × 10^?14; IO + CH₃SH → products (2): k₂ = (6.6 ± 1.3) × 10^?16; IO + C₂H₄ →products (3): k₃ < 2 × 10^?16; IO + C₃H₆ → products (4): k₄ < 2 × 10^?16 (units are cm³ molecule^?1 s^?1). CH₃S(O)CH₃ and HOI were found as products of reactions (1) and (2), respectively. The present lower value of k₁ compared to our previous determination is discussed.     

Wave attenuation in an elastic medium

This article examines the propagation of viscoelastic (elastic) waves in a medium consisting of two layers of finite thickness. It is found that there is a mechanical effect manifest in the monotonic dependence of the damping factor on the parameters of the system. These dependences have distinct maxima and minima, thus making it possible to optimize the damping properties of systems by varying their geometric parameters.Translated from Dinamicheskie, Sistemy, No. 4, pp. 57–62, 1985.     

Lipid chain mobility in interdigitated DPPC systems

The segmental lipid chain mobility in the gel phase of dipalmitoylphosphatidylcholine (DPPC) multilayers dispersed in buffer and in the interdigitated gel phase induced by glycerol, ethylene glycol, ethanol and chaotropic salt NaClO₄ was compared by using conventional electron spin resonance (ESR) spectroscopy. The stearic acids bearing the nitroxide moiety at different positions down the acyl chain (n-NSA,n-5, 7, 10, 12 and 16) were used to characterized the chain motion, and the outer hyperfine splittings of the spectra, 2A _max, were taken as indices of the rotational mobility of the chain in the gel phase. The ESR measurements revealed a gradient of increased mobility on proceeding towards the terminal methyl end in the fully hydrated gel phase of DPPC bilayers. This gradient was reduced in the interdigitated gel phase induced by ethanol and chaotropic salt NaClO₄, whereas the rotational mobility throughout the length of the chain was comparable to that near the polar/apolar interface in the interdigitated gel phase in glycerol and ethylene glycol. Moreover, the motional anisotropy was much less affected by temperature in the interdigitated gel state of DPPC in glycerol and ethylene glycol as compared both to normal bilayer gel phase and to the other interdigitated DPPC systems. Finally, there was no evidence for chain interdigitation in the fluid phase of DPPC dispersions in any medium.     

A positron annihilation study in some amorphous scintillators

Two organic scintillators — NE104 and a liquid solution of 2,5 diphenyloxazole (PPO) — were investigated through positron annihilation spectroscopy to study the influence of the structural order on the magnetic quenching effect on positron bound systems in solids.Preliminary note in [11]     

Transient vibrations of a tau inclined cable with a riding accelerating mass

The objective of this paper is a theoretical and numerical study of the dynamics of a taut inclined cable with a riding accolerating mass, which is suspended from two points of different elevation. The moving mass is a trolley that is accelerated by a solid fuel rocket down the inclined cable and is aerodynamically brought to a halt. The thrust of the rocket is tangential to the deformed configuration of the cable.Methods of analysis consist of the dynamics of small deformations superimposed on the static catenary state. The problem is nonlinear due to presence of friction and the convective acceleration interaction of the moving mass and the cable. Galerkin's procedure for removal of spatial dependence and numerical integration are used to obtain convergent solutions.Deceased     

Production of slow muonic hydrogen isotopes in vacuum

Muonic hydrogen isotopes (μ⁻ p, μ⁻ d, and μ⁻t) are simple quantum mechanical systems ideally suited for studies of numerous fundamental phenomena in electroweak and strong interactions as well as in applied areas such as muon chemistry or muon catalyzed fusion. Emission of muonic hydrogen isotopes into vacuum helps to overcome the limitations which are normally imposed on conventional investigations with gaseous and liquid targets. A proof of principle experiment for this new technique was performed at TRIUMF last year. Negative muons with 30 MeV/c momentum were stopped in a thin film of solid hydrogen and produced very low energy μ⁻d in vacuum. The distribution center of the normal velocity components of emitted μ⁻d atoms was measured to be ∼1 cm/μs. The yield of μ⁻d in vacuum is an increasing function of H₂ film thickness δ up to a value of δ≥1 mm.     

Quantum diffusion of muonium in GaAs

The diffusion rate of muonium in the III–V compound semiconductor GaAs has been determined from measurements of muon spinT ₁ relaxation induced by motion in the presence of nuclear hyperfine interactions. It is shown for the first time in a semiconductor that (a) there is a crossover of the transport mechanism at about 90 K from stochastic to zero-phonon hopping, as evidenced by a steep rise in the hop rate at lower temperatures, and that (b) the muonium diffuses at the hop rate of 10¹⁰ s⁻¹ (corresponding diffusion constantD≈10⁻⁶ cm²s⁻¹) at lower temperatures as well as at room temperature.