Highly accurate calculation of radial spheroidal functions

A new method for calculating the radial spheroidal functions of the first kind is proposed for the arguments that are greater than unity in modulus. A well-known representation of these functions is refined and used for this purpose. The constructs and the software implementation proposed in the paper provide an efficient tool for the calculation of the functions with a desired accuracy in a wide range of parameters.     

Mass spectrometric analysis of mixtures without separation

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, p. 1450, June, 1989.     

The kinetics of living free-radical polymerization of styrene in the presence of alkoxyamine: Interpretation within the framework of secondary inhibition hypothesis

The kinetics of the free-radical polymerization of styrene at 120°C in the presence of alkoxyamine as a living polymerization agent has been studied. The alkoxyamine forms in situ with a 100-fold variation in the initial concentration of 2,2,6,6-tetramethyl-1-piperidinyloxy. The rate of the process at the stationary stage decreases with an increase in the initial concentration of 2,2,6,6-tetramethyl-1-piperidinyloxy. The computer simulation of the kinetic features of the process under study demonstrates that this tendency is related to the possible secondary inhibition of the process by alkoxyamine and/or hydroxylamine arising in the system in the course of polymerization.     

Optical Gain of 1550-nm Range Multiple-Quantum-Well Heterostructures and Limiting Modulation Frequencies of Vertical-Cavity Surface-Emitting Lasers Based on Them

Results of investigation of 1550 nm range stripe semiconductor lasers fabricated from heterostructures with different designs of the gain medium are presented. It is shown that the proposed designs of the gain medium allow obtaining the effective lasing at high level of total optical losses, comparable with the typical optical losses in the vertical-cavity surface-emitting lasers. The evaluation of modal gain in different types of the gain mediummade it possible to estimate the possible frequencies of the small-signal modulation of vertically emitting lasers and proposed the ways to increase them up to 20 GHz or more.     

Amplification of a Raman Scattering Signal by Carbon Nanotubes

Doklady Physics - The effect of Raman scattering (RLS) signal amplification by carbon nanotubes (CNTs) was studied. Single-layered nanotubes were synthesized by the chemical vapor deposition (CVD)...     

Separation technique based on electrophoresis,chromatography and magnetism phenomena: the migration time and peak broadening

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Electrochemical method for producing radionuclide Lu-177 with high specific activity

A modified method for the isolation of radionuclide ¹⁷⁷Lu obtained from a Yb-176 target irradiated with thermal neutrons is proposed. The method consists of the combination of two electrochemical processes— cementation of ytterbium acetate–chloride solution to sodium amalgam and subsequent electrolysis of the ytterbium solution in a separate electrolytic cell without adjusting the solution. The electrochemical setup consisting of two cells gives the purification factor of ¹⁷⁷Lu from ytterbium at a level of 10⁵–10⁶, which allows using ¹⁷⁷Lu of such quality for labeling bioorganic molecules.     

Increase in the coercivity of an ensemble of (DyPr)–(CoFe)–B microparticles during their dispersion in a polymer matrix

In ensembles of annealed ferrimagnetic alloy (DyPr)–(CoFe)–B microparticles in the free state and fixed in polymer, the coercivity differs more than by an order of magnitude. The contributions of orientation locking of magnetic axes of particles and the dipole magnetic interaction between particles to the coercivity and saturation magnetization field of an ensemble are discussed. In ensembles of unannealed microparticles, the effect of their locking and dispersing in polymer is significantly weaker.     

Electrochemical Biosensor Based on Nanosized Polymer-Enzyme Films Composed of Linear Poly(N,N-Dimethylaminoethyl Methacrylate) and Choline Oxidase

Moscow University Chemistry Bulletin - Nanosized polymer-enzyme films were fabricated on graphite surfaces via a sequential two-stage adsorption of the pH- and thermoresponsive polymer, viz.,...     

Quasi-monochromatic radiation source with the wavelength tunable in the entire visible range

A quasi-monochromatic radiation source whose wavelength is continuously tuned in the visible spectral range is presented. The source is based on a short-arc high-pressure xenon lamp and an acousto-optic filter. The tuning range is 420–670 nm, the characteristic time of the wavelength tuning is 18 μs, and the radiation spectral width is 10 nm.