Appearance of anomalous phase in <Superscript>4</Superscript>He crystal in the presence of small <Superscript>3</Superscript>He impurity

The kinetics of formation of an anomalous phase from a solution with a small ³He impurity was studied in the temperature range 0.2–0.7 K up to a supersaturation of ～30 mbar. The phase diagram was determined for normal and anomalous growths. It is found that, in the presence of impurities, the formation of a fast-growing state is retarded. This experimental fact indicates that the dissipative processes in fluids have an appreciable effect on the phase formation kinetics. The retardation is, possibly, caused by the direct interaction of an impurity with the crystal surface.     

Kinetics of the thermal decomposition of bis(trifluoromethyl) peroxydicarbonate,CF3OC(O)OOC(O)OCF3

Thermal decomposition of bis(trifluoromethyl) peroxydicarbonate has been studied. The mechanism of decomposition is a simple bond fission, homogeneous first‐order process when the reaction is carried out in the presence of inert gases such as N₂ or CO. An activation energy of 28.5 kcal mol^?1 was determined for the temperature range of 50–90°C. Decomposition is accelerated by nitric oxide because of a chemical attack on the peroxide forming substances different from those formed with N₂ or CO. An interpretation on the influence of the substituents in different peroxides on the O? O bond is given. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 15–19, 2003     

Microwave‐improved polymerization of ϵ‐caprolactone initiated by carboxylic acids

The ring‐opening polymerization of ε‐caprolactone (ε‐CL), initiated by carboxylic acids such as benzoic acid and chlorinated acetic acids under microwave irradiation, was investigated; with this method, no metal catalyst was necessary. The product was characterized as poly(ε‐caprolactone) (PCL) by ¹H NMR spectroscopy, Fourier transform infrared spectroscopy, ultraviolet spectroscopy, and gel permeation chromatography. The polymerization was significantly improved under microwave irradiation. The weight‐average molecular weight (M_w) of PCL reached 44,800 g/mol, with a polydispersity index [weight‐average molecular weight/number‐average molecular weight (M_w/M_n)] of 1.6, when a mixture of ε‐CL and benzoic acid (25/1 molar ratio) was irradiated at 680 W for 240 min, whereas PCL with M_w = 12,100 and M_w/M_n = 4.2 was obtained from the same mixture by a conventional heating method at 210 °C for 240 min. A degradation of the resultant PCL was observed during microwave polymerization with chlorinated acetic acids as initiators, and this induced a decrease in M_w of PCL. However, the degradation was hindered by benzoic acid at low concentrations. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 13–21, 2003     

A study of the atmospheric lead pollution in Seville, Spain. Influence of meteorology and traffic, and relationship with other traffic-generated pollutants

A study of the atmospheric pollution by suspended particulate lead in the city of Seville, Spain, was carried out during the period between March 1983 and February 1984. The results obtained from seven sampling stations allowed us to study the site to site variations; there are two locations with average annual concentrations higher than 2 micrograms X m-3. In one station, the meteorological and traffic effects and relationship with other traffic-related pollutants, were investigated. The regression analyses performed on the average monthly data have shown an inverse correlation with wind speed and temperature and a direct correlation with carbon monoxide and smoke concentrations, but no significant correlation was found with the lead deposition levels.     

Recyclization of Products Formed by Addition of 5-Hydrazino-2-phenyl-1,3-oxazoles Functionally Substituted in 4-Position to Aryl Isothiocyanates

Russian Journal of General Chemistry -     

Elastoplastic torsion theory for whisker crystals

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 2, pp. 127–134, March–April, 1991.