Effects of scanning speed on the laser beam profile measurements by vibrating wire

For measuring laser beam profiles, a vibrating wire monitor (VWM) has been introduced. The measurements were carried out at different speeds of scan. Preliminary estimates were made for the calculation of the VWM response times with respect to the thermal losses along the wire, and radiative and convective losses. These estimates, however, do not determine the difference between the beam profile and the frequency response of the VWM for a given scan rate. To evaluate the reliability of the frequency response of the VWM, comparisons between forward and reverse beam scans at different speeds have been used. The results of these scans are used to correct the thermal inertia in the frequency response of the VWM.     

Influence of External Conditions on the Relation between the Physical and Chemical Processes in the Thermodegradation of Plasticized Poly(Vinyl Chloride)

The heat-induced loss of plasticizer from and dehydrochlorination of poly(vinyl chloride) plasticized with dioctyl phthalate is studied by thermogravimetric analysis, IR spectroscopy, and colorimetry. Specific features and general regularities of the processes at high (200–320°C) and medium (100–132°C) temperatures are established. It is shown that the dehydrochlorination and oxidation processes dominate in confined space whereas, in unconfined space, plasticizer is lost largely through evaporation. The activation energies of the initial stages of the processes are determined.     

Four-component couplingvia a sequence of threeAd E reactions involving arenesulfenyl chloride, two alkyl vinyl ether units, and silicon-containing π-donors as a method for the synthesis of polyfunctional compounds

A protocol for the synthesis of polyfunctional compounds by a Lewis acid initiated tandem sequence of threeAd _E reactions of sulfur-containing electrophiles with two alkyl vinyl ether units and silicon containing π-donors is proposed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya No. 5, pp. 924–932, May, 1998.     

Structure-sensitive liquid flowable compositions based on polyvinyl alcohol and silicotungstic acid

Conditions of the formation of structure-sensitive liquid flowable media based on 1.5 and 10% aqueous solutions of polyvinyl alcohol containing silicotungstic acid and water-soluble carboxy-methylcellulose in the form of its potassium salt (Na-CMC) are examined. Rheological, optical, and dielectric relaxation methods revealed the formation of several types of interpolymer complexes in the examined liquid flowable media. This leads to the formation of associates and an increase in the molecular mobility of the macromolecules and their fragments. The structure and properties of the complexes depend on the composition of the media as well as the method of introducing polyacids. It was found that it was possible to control the structure of such solutions by applying a mechanical of magnetic field. The compositions obtained can be used for producing anisotropic light-, electric-, and heat-sensitive film materials, as well as sensors of different types.Presented at the 10th International Conference on the Mechanics of Composite Materials (Riga, April 20–23, 1998).Institute of General and Inorganic Chemistry, Belarus Academy of Sciences, Minsk, Belarus. Translated from Mekhanika Kompozitnykh Materialov, Vol. 34, No. 3, pp. 413–424, May–June, 1998.     

Si-C-Bond cleavage in 1-organylsilatranes by bromine or iodine chloride

The Si-C bond in I-organylsilatranes is cleaved by bromine or iodine chloride to yield 1-bromo- or 1-chlorosilatrane respectively. In the presence of Et2O or THF and under the action of dioxane dibromide, I-halosilatraneTranslated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 2075–2077, August, 1996.     

Reaction of chloro-arylthio adducts of 1,1-dimethylallene with trimethylsilyl enol ethers—A method of 2-arylthioprenylation of carbonyl compounds

Conclusions The adduct of 1,1-dimethylallene with arylsulfenyl chlorides can be used to introduce the 2-aryltyioprenyl residue into molecules of carbonyl compounds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 392–395, February, 1985.     

Activity and bond strength of surface oxygen in vanadium oxide catalysts for methanol oxidation

Catalytic activity and bond strength of oxygen to the surface of V–Mo–O, V–Sb–O and V–Sn–O catalysts have been examined. It has been established that the surface of these catalysts contains only strongly bonded oxygen, which, along with some other factors, accounts for their selectivity in the partial oxidation of methanol.

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