Arene sulfenylation by arenesulfenamides and arenesulfenylacetates

Two systems for arene sulfenylation were investigated: arenesulfenamides in the presence of SO₃ and sulfenylacetate complexes with AlBr₃. A preference for the second reagent was demonstrated for sulfenylation of substrates bearing donor substituitents.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 324–326, February, 1995.     

A local search approach to a circle cutting problem arising in the motor cycle industry

This paper is concerned with the development of a customized circle packing algorithm for a manufacturer of sprockets for the motor cycle industry. Practical constraints mean that the problem differs somewhat from those tackled elsewhere in the literature. In particular, the layouts need to conform to a given structure. This is achieved by using a local search algorithm with an appropriate starting solution and a series of neighbourhoods designed to preserve the layout structure. Empirical evidence based on real data shows that the quality of the resulting solutions closely matches that of cutting patterns currently produced by human experts. Computation times average around 20–30?s per order as compared to several hours for an equivalent manual solution.     

Controllability of Functional Integro-Differential Inclusions with an Unbounded Delay

In this paper, a sufficient condition is established for the controllability of neutral functional integro-differential inclusions with an unbounded delay in Banach spaces. The approach used is a fixed-point theorem for condensing maps due to Martelli and the theory of analytic semigroup of linear operators. Communicated by F. Zirilli Research supported by NNSF of China, by the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of the Ministry of Education of China, and by the Qing Lan Talent Engineering Fund QL-05-164 of Lanzhou Jiaotong University. The authors are grateful to Professor F. Zirilli and two anonymous referees for valuable suggestions improving this paper.     

Discovery of a new long-lived isomeric state in 125Ce

A new long-lived isomeric state in the near proton dripline nucleus ¹²⁵Ce has been identified with Schottky mass spectrometry at GSI. The excitation energy E ^* = 103(12)keV and the decay time of 193(1)s have been obtained from a single stored fully ionized ^125m Ce⁵⁸⁺ ion. The data implies an E3 transition and a 1/2⁺ assignment for the spin of the isomer.     

Neutron reflection from a helical system

Analytical expressions for neutron reflection and transmission by magnetic mirrors with helical magnetization are derived. Reflectance curves with and without neutron spin flip are presented. Resonant properties of helical systems are studied.     

Sound propagation in an unstable atmospheric layer

The equation of sound propagation in an unstable medium produced by the presence of supersaturated water vapor in it, which can appear in a hurricane area, is derived. This equation takes into account the effects of sound velocity dispersion, amplification, damping, and nonlinear effects. Some solutions to this equation are presented, illustrating the specific features of sound propagation in an unstable medium. Published in Akusticheskiĭ Zhurnal, 2007, Vol. 53, No. 3, pp. 477–480.     

Analysis of (π K<Superscript>+</Superscript>) and (K<Superscript>-</Superscript>, K<Superscript>+</Superscript>) hypernuclear production spectra in distorted-wave impulse approximation

We study the hyperon-nucleus potential with distorted-wave impulse wave approximation (DWIA) using the Green's function method. In order to include the nucleon and hyperon potential effects in Fermi averaging, we introduce the local optimal momentum approximation of target nucleons. We can describe the quasi-free Λ , Σ and Ξ production spectra in a better way than in the standard Fermi-averaged t -matrix treatments.     

Fast frequency estimation and tracking using Lagrange interpolation

A computationally efficient and accurate frequency estimation and tracking algorithm is proposed, based on the adaptive frequency estimator (AFE) of Etter and Hush. A Lagrange interpolator (a fractional delay filter) is used to estimate the gradient of the performance surface of the adaptation, which enables highly accurate estimation. The performance of the new algorithm is demonstrated in the context of tracking a chirp signal in noise     

Effect of p-toluensulfonic acid on oxidation of polyethylene and polyethylene-poly-p-methylstyrene blends

p-Toluensulfonic acid retards oxidation of polyethylene and, to a greater extent, of polyethylene-poly-p-methylstyrene blends. The real antioxidant is p-cresol, formed by p-toluensulfonic acid transformation in oxidizing polyethylene and, in blends, through peroxidation and subsequent acid-catalyzed decomposition of hydroperoxides of poly-p-methylstyrene.