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71.
Electrocapillary phenomena at the n-heptane/water interface in the presence of phosphatidylcholine or phosphatidylethanolamine in alkane were studied by the drop-volume technique. The regulating role of the electric field was established in phospholipid interaction with inorganic ions: changes in interfacial pressure at the n-heptane/water interface with addition of electrolytes were observed only when an electric field was applied to the system of two immiscible liquids. It is suggested that ions can penetrate and bond by phospholipid functional groups at the phase boundary only after reorientation of the latter in the electric field. As in the case of ionic surfactants, change in interfacial pressure was directly proportional to the cube root of the concentration of electrolyte. It is assumed that as a result of preferential binding by phospholipid functional groups of ions of one sign, lipid molecules are charged and at the phase boundary behave themselves like ionic surfactants. Experiments with salts of multicharged ions, La3+, [Fe(CN)6]3−, and [Fe(CN)6]4−, have shown that mainly phospholipid functional groups bind cations. 相似文献
72.
73.
A.V. Voitsekhovskii D.I. Gorn S.N. Nesmelov A.P. Kokhanenko 《Opto-Electronics Review》2010,18(3):241-245
The purpose of this scientific work is the research of energy-band diagrams and capacity-voltage characteristics of CdxHg1−xTe-based variband heteroepitaxial structures with taking into account the dependence of electron affinity on the composition. 相似文献
74.
Grigorii E. Ivanov 《Topology and its Applications》2008,155(8):851-857
We obtain some selection theorems for multifunctions with weakly convex values. For this purpose, some new properties of weakly convex sets in a Hilbert space are investigated. We also present some examples showing the importance of various assumptions in these selection theorems. 相似文献
75.
Boris A. Trofimov Anastasiya G. Mal'kina Valentina V. Nosyreva Alexander I. Albanov Grigorii G. Alexandrov Oleg A. Dyachenko 《Tetrahedron》2009,65(12):2472-288
2-Aminobenzoic acid 1 reacts with α,β-acetylenic γ-hydroxy nitriles 4 and 5 to afford 2-[(5-iminio-2,2-dialkyl-2,5-dihydro-3-furanyl)amino]benzenecarboxylates 7 and 8 (yield 73-74%), a new class of unnatural amino acids in a peculiar zwitterionic form, having the positive charge transferred to the remote imino group of the dihydrofuranyl substituent. 3- and 4-Aminobenzoic acids 2 and 3 with α,β-acetylenic γ-hydroxy nitriles 4-6 undergo entirely different transformations to deliver the esters of cyanomethylhydroxyalkyl ketones 9-12, which result from the unusually facile esterification of the hydroxyl function and simultaneous hydration of the triple bond. 4-Aminobenzoic acid 3 is found to be an active organic catalyst for the one-pot conversion of α,β-acetylenic γ-hydroxy nitrile 4 to 5-amino-2,2-dimethyl-3(2H)-furanone 13, in 80% yield. 相似文献
76.
Olga N. Kazheva Grigorii G. Alexandrov Andrey V. Kravchenko Igor B. Sivaev Vladimir I. Bregadze 《Journal of organometallic chemistry》2006,691(20):4225-4233
New radical cation salts (TMTSF)2[3,3′-Co(1,2-C2B9H11)2] (1), (TTF)[3,3′-Co(1,2-C2B9H11)2] (2) and (ET)[3,3′-Co(1,2-C2B9H11)2] (3) were synthesized and their crystal structures and electrical conductivities were determined. Compound 1 has layered structure with conducting stacks of the TMTSF cations, whereas compounds 2 and 3 contain separated pairs of fulvalenium cations. Conductivity of crystals 1 at room temperature was found to be 15 Ohm−1 cm−1, that is the maximum value found for fulvalenium metallacarborane salts. 相似文献
77.
The plane stability problem for a rectangular, linearly elastic, isotropic plate with a central crack is solved. The dependence of the critical load on the crack length is studied using exact (the three-dimensional linearized theory of stability of elastic bodies) and approximate (beam approximation) approaches. The results produced by the beam approach are evaluated.Translated from Prikladnaya Mekhanika, Vol. 40, No. 11, pp. 117–126, November 2004.This revised version was published online in April 2005 with a corrected cover date. 相似文献
78.
The paper studies the dependence of edge effects in a laminated composite of regular structure with a periodic system of symmetric interfacial cracks on the mechanical characteristics of the composite components. Loading the composite induces constant strain in the reinforcement direction. The problem is solved in exact formulation using the linear elastic equations for piecewise-homogeneous media and a criterion for quantitative evaluation of edge effects. An approximate solution of the problem is found by the mesh approach. A difference scheme for the mixed problem under consideration is derived. The edge-effect zones for normal stresses are constructed. The maximum values of the normal stress concentration factors are determined 相似文献
79.
80.
Lyubov N. SobeninaZinaida V. Stepanova Igor’ A. UshakovAl’bina I. Mikhaleva Denis N. TomilinOl’ga N. Kazheva Grigorii G. AlexandrovOleg A. Dyachenko Boris A. Trofimov 《Tetrahedron》2011,67(26):4832-4837
Ethyl 3-(4,5,6,7-tetrahydroindol-2-yl)propynoate, readily available from 4,5,6,7-tetrahydroindole and ethyl bromopropynoate, when treated with dichlorodicyanobenzoquinone (DDQ) in methanol affords furan-2-one-4,5,6,7-tetrahydroindole-cyclobutene sequence in a 52% yield. As kinetic and minor products, a furan-2-one isomer along with bicycloheptadienone have been either isolated or identified. The reaction has been shown to proceed via the isolable intermediate the [2+2]-cycloadduct of ethyl 3-(4,5,6,7-tetrahydroindol-2-yl)propynoate with DDQ. Other alcohols react with the [2+2]-cycloadduct in a similar way. The effect of the alcohol structure on the products ratio has been analyzed. All the intermediates and products are formed as single diastereomer, thus indicating a concerted character of the rearrangement. 相似文献