Intensification of Preparation of Modified Polycaproamide Fiber

A procedure was developed for graft polymerization of dimethylaminoethyl methacrylate onto polycaproamide using a redox system whose components are added to the reaction mixture sequentially. A scheme of radical graft polymerization of dimethylaminoethyl methacrylate onto polycaproamide was suggested. The properties of the copolymers were studied. The materials based on modified polycaproamide show promise as chemisorbents.     

Synthesis of Novel Five-membered Nitrogen-containing Heterocyclic Compounds from Derivatives of Arylsulfonyl- and Arylthioacetic and -Propionic Acids

A series of novel substituted 1,3,4-oxa(thia)diazoles and triazoline-3-thiones has been synthesized from thiosemicarbazides and nitriles of arylthio-, arylsulfonylacetic and -propionic acids. A mechanism is proposed for the preparation of 2-amino-5-substituted 1,3,4-thiadiazoles from carboxylic acids in polyphosphoric acid medium.     

Influence of resonators on the acoustic and propulsion performance characteristics of a ramjet ejector chamber under conditions with vibration hydrogen combustion

The influence of acoustic resonators on the acoustic and propulsion performance characteristics of a ramjet ejector chamber under conditions with vibration hydrogen combustion was experimentally examined. In the study, resonators having identical throats and different cavity diameters were used. For fixed-volume resonators the best propulsion performance characteristics were achieved in the case in which the cavity diameter differed little from the resonator throat diameter.     

Synthesis of 3-(4-Oxo-4H-3,1-benzoxazin-2-yl)-1-benzenesulfonyl Chloride and Its Reactivity toward Amines

3-(4-Oxo-4H-3,1-benzoxazin-2-yl)-1-benzenesulfonyl chloride was synthesized, and reactivity of its functional groups was studied. Reactions of the title compound with equimolar amounts of aniline and piperidine gave the corresponding sulfonamides with retention of the benzoxazine moiety. The same reactions with excess amine resulted in opening of the oxazine ring and formation of o-(m-aminosulfonylbenzoylamino)benzamides.     

Low-Temperature Synthesis of Glass-Ceramics with YNbO4:Eu3+ Crystallites

Optics and Spectroscopy - The main aim of this work was to perform low-temperature synthesis of glass-ceramics with YNbO4:Eu3+ crystallites and study the structural and luminescent properties of...     

Cascade synthesis of new aryl 2-phenylallyl sulfones from α-methylstyrene and aromatic mono- and bis-sulfonyl chlorides

Addition products of arenesulfonyl chlorides to α-methylstyrene in the presence of catalytic amounts of copper(II) chloride and triethylamine hydrochloride underwent fast dehydrochlorination (according to Hofmann’s rule) on heating in boiling acetonitrile to give the corresponding aryl 2-phenylallyl sulfones with high selectivity. This reaction underlay a one-pot procedure for the synthesis of new compounds that attract interest as potential biologically active substances, monomers, and cross-linking agents for polymeric materials from accessible starting compounds.     

Mathematical modeling of prolonged cycling of a porous cadmium electrode in alkaline power sources

An analysis of a computer model of a porous cadmium electrode is presented. The model describes prolonged cycling of the electrode under the alkaline battery conditions. It allows the evaluation of the dependence of the cathodic and anodic polarization on the concentration of the alkaline electrolyte, the charge and discharge current density, and the thickness and porosity of the electrode. The effect of the mass transfer of the active substance along the electrode thickness on the electrode capacity during the battery cycling can also be predicted. The calculations took into account that the cathodic and anodic processes on the cadmium electrode occurred by the liquid- and solid-state mechanisms. The diffusion, migration, and convective transport of the electrolyte components were also taken into account. An analysis of data using this model showed that it can be used in studies of the capacity of sintered cadmium electrodes under different operating conditions of nickel-cadmium batteries.     

Transmission System for Broadband Analog Signals Using External Modulation of Optical Radiation

Fiber optic communication lines on the basis of the Mach–Zehnder intensity modulator can be used in studies of pulsed plasma for transmission of signals from detectors to data acquisition equipment. In this study, a system for transmission of nanosecond signals over fiber optic cables in the ranges of 1550 and 850 nm is demonstrated. A chronographic electro-optical detector is used for recording the signals in the range of 850 nm.     

A Sonic Boom from a Thin Body and Local Heating Regions of an Incoming Supersonic Flow

Technical Physics - The problem of the sonic boom from a thin body and local heating region of an incoming supersonic flow is solved numerically. The Mach number of the incoming air flow is 2....