Tribological properties of fluoroplastics modified with fullerene black in sliding friction with water lubrication

Effect of fullerene black additives on the antifriction properties and wear resistance of F-4 and F-4K20 fluoroplastics in sliding friction against steel with water lubrication was examined.     

Thermodynamic properties of alkaloids lappaconitine and glaucine

Calorimetric methods were used to study the enthalpy of solution of the alkaloids glaucine C₂₁H₂₅NO₄ and lappaconitine C₃₂H₄₄N₂O₈ in 96% ethanol and their heat capacity in the temperature ranges 173–298.15 and 173–423 K. Equations describing the dependences ΔH _sol ^m ～ f( $\sqrt m $ ) (m is molal concentration) and C _p ⁰ ～ f( $\sqrt T $ ) for the compounds under study were derived. The enthalpies of combustion, melting, and formation of C₂₁H₂₅NO₄ and C₃₂H₄₄N₂O₈ were estimated by means of theoretical calculations.     

Mechanoluminescence and submicrorelief of a copper surface

Copper plates are irradiated with pulsed laser light on one side, and the opposite side is investigated with a scanning tunneling microscope. It is found that the submicrorelief of the back surface changes after irradiation. During irradiation it emits a light pulse. It is established that a relation exists between the luminescence intensity and the magnitude of the change in the surface submicrorelief. Zh. Tekh. Fiz. 69, 102–104 (December 1999)     

Formation of triphenylmethyl radicals upon alkaline hydrolysis of diphenyl sulfophthalide

Triphenylmethyl radicals (TPMR) with ano-positioned sulfonate group are generated by alkaline hydrolysis of diphenyl sulfophthalide in DMSO. Electronic and ESR spectra of these radicals are characterized. It is suggested that the radicals result from one-electron transfer reactions. Triarylmethyl radicals are also formed in alkaline hydrolysis of polyarylenesulfophthalides. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2015–2017, October, 1999.     

Acylation of acetylcellulose with pyromellitic dianhydride

The cross-linking reactions of acetylcelluloses having different levels of acetyl groups with pyromellitic dianhydride in homogeneous media have been investigated. A relationship has been established between the static exchange capacity (SEC) and the content of hydroxy groups in the acetylcellulose and the exterification conditions (homogeneous or heterogeneous-solid phase). It has been shown that on the interaction of acetylcellulose with pyromellitic dianhydride under homogenous conditions there is a uniform distribution of cross-linkages over the whole length of the acetylcellulose macromolecule, which enables products with high SEC values to be obtained.Tashkent Institute of Chemical Technology. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 515–520, July–August, 1999.     

Liquid chromatography of polysaccharides

This review gives an analysis of methods of high-performance liquid chromatography for the separation of various polysaccharides.Institute of the Chemistry and Physics of Polymers, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 144 26 61. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 3–18, January–February, 1999.     

Physicochemical properties and kinetics of transferase activity of invertase

The transferase activity of yeast invertase is found as a function of pH and reaction temperature. The degree of conversion into alkylfructosides depends on the substrate (alcohol) and enzyme concentrations and on the incubation time of the reaction mixture. The effect of ethanol concentration on transferase activity of the enzyme is determined. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 781–784, November–December, 1999.     

Electrochemically controlled methods for removal of endo- and exotoxicants from biological media

The electrochemical model of the system of electroconductive hemosorbent/biological medium was proposed to develop electro-chemically controlled medical detoxification technologies for treat-ment of diseases of certain etiology. It was obtained that the destruc-tion of blood cells as a result of a contact blood with hemosorbents is caused of hemosorbent potential. The potential region of hemosor-bent corresponding of hemocompatibility was determined. Hemo-compatible composite material based on activated carbon covered polypyrrole were synthesized. Certain electrochemical medical tech-nologies for selective removing of endo- and exotoxicants and dam-aged blood cells from biological media of organism were developed.