Charged particle emission from transient plasmas

When a voltage pulse is applied to an interelectrode vacuum gap, bunches of transient plasma are formed on the cathode which are efficient emitters of charged particles. The present review gives the results of investigations of the cathode-plasma emissivity, the stability conditions of the high-voltage discharge phase, the mass-charge composition of the cathode plasma and its relationship to the threshold current of the cathode material, and the conditions for forming an anode plasma and its influence on the duration of the high-voltage discharge phase. Examples are given in which the results are used to create a wide range of electron and ion beams and current beakers.Institute of Power Electronics, Siberian Branch, Russian Academy of Sciences. G. P. Bazhenov Institute of Electrophysics, Urals Branch, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 83–99, March, 1994.     

Effect of ozone on poly(vinyl chloride) degradation

The influence of ozone on the kinetics and mechanisms of poly(vinyl chloride) degradation has been studied. The rate constants for reaction of ozone with saturated and unsaturated units of macromolecules have been measured. The products of the reaction of ozone with double bonds are inactive and do not influence the subsequent thermal dehydrochlorination of the polymer. The products of reaction of ozone with saturated units greatly increase dehydrochlorination.     

Galvanostatic Coulometric Determination of Salicylic Acid and Some of Its Derivatives Using Electrogenerated Halogens

Reactions of electrogenerated bromine and chlorine with salicylic acid and some of its derivatives were studied. Procedures for the galvanostatic coulometric determination of 2.4 to 19.2 g/mL of salicylic, acetylsalicylic, para-aminosalicylic acids and mesalazine in model solutions and medicinal preparations with electrogenerated halogens were developed (RSD varied from 1 to 5%). The end-point of coulometric titration was determined amperometrically with two polarized platinum electrodes.     

Coulometric Determination of Purine Alkaloid Series with Electrogenerated Chlorine

In acid solution, caffeine, theobromine, and theophylline are rapidly and quantitatively oxidized with electrogenerated chlorine in a stoichiometric ratio of 2 : 5 to give alloxan and urea. Procedures for the coulometric determination of microgram amounts of caffeine, theophylline, and theobromine in model solutions, caffeine in tea and coffee samples, and caffeine and theophylline in some pharmaceutical preparations were developed.     

Polymer-asphalt compounds based on 1,2-polybutadienes

Properties of polymer-asphalt compounds containing 1,2-polybutadienes differing in the molecular weight and structure of macromolecules were examined. Introduction of syndiotactic 1,2-polybutadiene in combination with a plasticizing additive noticeably improves the main service properties of asphalts.     

Obtaining of High-Power Electron Beams in a Plasma Anode Source Powered by the Marx Generator with Matched Loads

Russian Physics Journal - Experiments have been carried out to obtain high-power microsecond electron beams with high energy using an electron beam source with an explosive emission cathode and a...     

Dichlorocyclopropane derivatives of syndiotactic 1,2-polybutadiene

Polymeric products containing hem-dichlorocyclopropane units with a degree of functionalization of up to 97% are synthesized via the reaction of syndiotactic 1,2-polybutadiene with dichlorocarbene obtained by the interaction of chloroform with an aqueous solution of sodium hydroxide in the presence of a phase-transfer catalyst. The incorporation of dichlorocyclopropane groups into units of polydiene substantially changes its molecular mass and polydispersity, the solution viscosity, the polymer melt flowability, and the glass-transition temperature and flow temperature of the polymer.     

Annealing mechanisms of self-interstitial related defect E1=Ec−0.39 eV in irradiated silicon

DLTS and thermally stimulated capacitance (TSCap) studies of α-particle irradiated p-Si were undertaken to obtain additional information about the self-interstitial related defect E1=E_c−0.39 eV. The E1 defect can be retained frozen up to room temperature without any minority carrier injection, but under injection conditions at 77–300 K the E1 becomes mobile. As a result of annealing of the E1 defect, the carbon interstitial concentration grows. The E1 defect production rate under reverse bias as well as thermal annealing behavior depends strongly on the temperature and impurity concentration. Numerical estimates of the E1 migration via a Bourgoin–Corbett mechanism are in good agreement with the experimental data obtained.