Liquid Ion-Selective Electrodes for Determining Nonionic Surfactants

It was shown that nonionic surfactants (NS) can be determined by potentiometry using liquid NS-selective electrodes. The effect of medium acidity and foreign substances on the operation of liquid NS-selective electrodes was studied. Some properties of NS-selective electrodes were determined.     

Partially isometric dilations of noncommuting -tuples of operators

Given a row contraction of operators on a Hilbert space and a family of projections on the space that stabilizes the operators, we show there is a unique minimal joint dilation to a row contraction of partial isometries that satisfy natural relations. For a fixed row contraction the set of all dilations forms a partially ordered set with a largest and smallest element. A key technical device in our analysis is a connection with directed graphs. We use a Wold decomposition for partial isometries to describe the models for these dilations, and we discuss how the basic properties of a dilation depend on the row contraction.

     

Unsteady motion in single-line flow-injection systems

Unsteady motion in single-line flow-injection systems consisting of n tubular elements with valve or hydrodynamic injection is studied theoretically. A formula for the duration of the initial period of unsteady flow is derived. This initial period is much shorter than the mean residence time of the analyte in practical systems. It can therefore be neglected in mathematical modelling of such systems. Experimental data obtained with single-line systems with valve and hydrodynamic injection confirmed the validity of the theoretical equations.     

Reciprocating sliding wear behavior of laser-clad small amplitude Mo2Ni3Si/NiSi metal silicide composite coatings

Mo₂Ni₃Si/NiSi metal silicide composite coatings with a fine microstructure consisting of Mo₂Ni₃Si primary dendrites and the interdendritic Mo₂Ni₃Si/NiSi eutectics were fabricated on austenitic stainless steel AISI 321 by laser cladding process. Small amplitude reciprocating sliding wear resistance of the coatings is evaluated as functions of normal load and slip amplitude and the wear mechanisms were discussed based on worn surface morphology observations. Results showed that the Mo₂Ni₃Si/NiSi coatings have excellent small amplitude reciprocating sliding wear resistance.     

The preparation of 2-iodoamides from glucals and their further transformations into oxazolines

2-Deoxy-2-iodo-glycosylamides have been prepared from a variety of protected d-glucals by their reaction with N-iodosuccinimide and amides. Benzyl protected 2-iodoamides, when treated with sodium hydride and 15-crown-5, gave stable C1 N-linked 2-glycooxazolines as the major products. Silyl protected 2-iodoamides afforded the C1 O-linked 2-glycooxazolines; presumably by the rearrangement of unstable N-acylaziridine intermediates.     

Palladium-catalysed three component synthesis of α,β-unsaturated amidines and imidates

Palladium-catalysed three component coupling of an alkenylbromide, isonitrile and an amine or alkoxide/phenoxide affords α,β-unsaturated-amidines and -imidates.     

A new reaction of phosphorylated N-sulfonylimines with hydrophosphoryl agents involving C → N transfer of phosphoryl groups

Hydrophosphoryl nucleophilic agents add to the CN bond of N-sulfonyltrichloroacetimidoylphosphonates to give unstable C,C-diphosphorylated adducts, which undergo competitive 1,2-C → N phosphorotropic rearrangement and dehydrochlorination with the formation of aza-Perkow reaction products, C,N-diphosphorylated dichlorovinylsulfonamides. This is the first reliably identified case of an aza-Perkow transformation for acid phosphites and their initial nucleophilic attack at the C atom of the azomethine bond in the aza-substrates.     

Structure and properties of the mesophase of syndiotactic polystyrene. II. Effect of stepwise extraction on the preparation of the mesophase

In this study, a novel stepwise extraction method has been examined. The guest molecules housed between the helices of the clathrate δ form of syndiotactic polystyrene can be removed completely with this method. A systematic study of the preparation of a solvent‐free mesophase (emptied clathrate) membrane, its helical and residual solvent contents, and its structural transformations has been performed. In this first attempt, an enhancement in the TTGG helical content has been observed in the extracted membrane, and a conceptual mechanism is proposed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 269–273, 2003     

Beryllium (boron) clustering quest in relativistic multifragmentation (BECQUEREL Project)

A physical program of irradiation of emulsions in beams of relativistic nuclei named the BECQUEREL Project is reviewed. It is destined to study in detail the processes of relativistic fragmentation of light radioactive and stable nuclei. The expected results would make it possible to answer some topical questions concerning the cluster structure of light nuclei. Owing to the best spatial resolution, the nuclear emulsions would enable one to obtain unique and evident results. The most important irradiations will be performed in the secondary beams of He, Be, B, C, and N radioactive nuclei formed on the basis of JINR Nuclotron beams of stable nuclei. We present results on the charged state topology of relativistic fragmentation of the ¹⁰B nucleus at low energy-momentum transfers as the first step of the research.