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11.
D. G. Gromov S. A. Gavrilov E. N. Redichev A. V. Klimovitskaya R. M. Ammosov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(10):1650-1655
A method for calculating the temperature of fusion of thin films depending on their thickness was suggested. It was shown for the example of copper and nickel films that the main factors that determined a substantial decrease in the temperature of fusion of thin films compared with massive materials were the different heats of fusion of thin films, the temperature dependence of the heat of fusion, and the tendency of thin-film systems toward decreasing the absolute surface energy at the expense of decreasing the specific surface energy and surface area. The dependences of the temperature of fusion on the thickness of copper and nickel films were calculated. Fusion and dispersion processes were studied as depending on nickel film thickness on the surfaces of Al2O3 and SiO2. The calculation results obtained for copper and nickel were in close agreement with experimental data. 相似文献
12.
Macrocycle opening in derivatives of benzocrown ethers under the action of amines is affected by the nature of the heteroatoms in the macrocycle, the nature of the functional group in the benzene ring of the crown ether, and the length, branching, and number of hydrocarbon radicals at the amine nitrogen atom. A distinguishing feature of this reaction is the template effect of MeNH3
+, Me2NH2
+, Na+, and K+ ions.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 687–692, March, 1996.For Part I see Ref. 1. 相似文献
13.
A new method for synthesizing nitrogen-containing podands by nucleophilic regioselective cleavage of the macrocycle in formyl derivatives of benzocrown ethers by heating with methylamine and methylammonium chloride has been developed. This reaction is the first example of crown ether opening by a nitrogen-containing nucleophile.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 950–953, May, 1995. 相似文献
14.
Regiospecific introduction of the 2-naphthyl residue into position 4 of the pyridine ring occurs in the reactions of isoquinolinium salts with 4-methylpyridinium salts through the intermolecular transformation of the isoquinoline bicyclic system involving the methyl group of the pyridinium salt. The reaction occurs under the action of methylammonium sulfite in an aqueous medium on heating. This method provides ring transformation not only for isoquinolinium salts but even for unsubstituted isoquinoline. 相似文献
15.
P. M. Kochergin M. Yu. Gromov E. V. Aleksandrova S. Ya. Skachilova 《Chemistry of Heterocyclic Compounds》1993,29(11):1335-1339
The reaction of 6-purinethione with -haloketones has given a series of new 6--oxoalkyl(aralkyl, hetaralkyl, cycloalkyl)thiopurines. Their alkylation in position 9 and acid hydrolysis to hypoxanthine and its 9-alkyl derivatives has been studied. The hydrolysis of the acetals of 6-formylmethylthiopurine and the oxidation of 6-(2,3-dihydroxypropyl)thiopurine leads to 6-formylmethylthiopurine, which shows a ring-chain tautomerism and exists in the form of 7-hydroxy-7,8-dihydrothiazolo[2,3-i]purine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1548–1553, November, 1993. 相似文献
16.
V. P. Tsybyshev V. A. Livshits B. B. Meshkov O. A. Fedorova S. P. Gromov M. V. Alfimov 《Russian Chemical Bulletin》1997,46(7):1239-1244
An amphiphilic crown-containing styryl dye (1) was synthesized, and the effects of irradiation, temperature, and alkali and alkali-earth metal ions on the conductivity
and optical spectra of its solutions in dioctyl phthalate were studied. Compound1 in thetrans-form almost completely exists as ion pairs (IP). Irradiation at a long-wavelength absorption maximum (λmax) results in a reversible increase in the conductivity and, hence, a degree of dissociation of IP (α); these parameters decrease
when complexes with metal ions are formed. The relaxation times for the photoinduced conductivity coincide with a decrease
in the extinction within experimental error in the 20–60°C temperature range. The photoinduced increase in α is caused bytrans—cis-isomerization and an increase in steric hindrances for the interaction of the ClO4
− anion with the N+ atom of benzothiazolium in thecis-form of1. The activation energies for the darkcis—trans-relaxation, absolute α values, and thermodynamic parameters of dissociation of IP in thetrans-form, as well as the α values in a photostationary mixture ofcis—trans-isomers, were estimated. The decrease in α after binding with metal ions is likely caused by the redistribution of the positive
charge to benzothiazolium through the conjugated system of1. Correlations between the decrease in conductivity (decrease in α) and the hypsochromic shift Δλmax after the formation of complexes between1 and metal ions were observed.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1296–1301, July, 1997. 相似文献
17.
P. B. Terent'ev O. A. Solov'ev R. A. Khmel'nitskii S. P. Gromov R. S. Sagitullin 《Chemistry of Heterocyclic Compounds》1982,18(6):578-580
Peaks of [M — NO]+ and [M — NO2]+ ions are characteristic for the mass spectra of nitroindolizines, whereas peaks of ions of the indole type, viz., [M — HCN]+ and [M- H,- HCN]+ (for alkylindoles), are not characteristic. In the mass spectra of nitroindoles the latter ions give more intense peaks, while the loss of a nitro group or its rearrangement is a considerably less significant process. When a dialkylamino group is introduced in the nitroindolizine molecule, the primary processes in the fragmentation of such compounds are due to fragmentation of the alkylamino group.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 765–768, June, 1982. 相似文献
18.
19.
M. Gromov 《Geometric And Functional Analysis》1991,1(3):253-320
Our basic results concerning harmonic maps are parallel to those in Part I [Gro11] about minimal subvarieties. First we produce compact harmonic foliations
by solving in some cases the asymptotic Dirichlet problem. Then we construct transversal measures by adopting the parabolic equation method of Eells and Sampson. Finally we indicate some applications to the rigidity and the pinching problems. 相似文献
20.
Selective etching has been applied to the mobilities of pyramidal dislocations in the {11¯22} 11¯23 system in Zn single crystals in the quasiviscous region in the simultaneous presence of mechanical treatment and current flow in order to establish the mechanisms whereby current pulses affect metal plasticity. The dislocation dynamics may be related to the current density and mechanical loading, which is examined in relation to the possible current-effect mechanisms. The dynamic retardation constant has been estimated and it has been found that the nonpolar pinch effect and direct force action from the current are decisive.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 5–8, August, 1991.We are indebted to A. M. Roshchupkin and I. L. Bataronov for discussions and critical comments. 相似文献