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1.
M. Z. Krimer F. Z. Makaev E. P. Styngach A. G. Koretskii S. I. Pogrebnoi A. I. Kochug 《Chemistry of Heterocyclic Compounds》1996,32(9):1035-1039
A new method is proposed for the preparation of 2-amino-l-arylidenaminoimidazoles, which react with-haloketones to give a series of 1-arylidenamino-3-acylmethyl-2-iminoimidazolines and 1-arylidenaminoimidazo [1, 2-a]imidazoles depending on the conditions.Institute of Chemistry of the Republic of Moldova, 277028 Kishinev.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1209–1213, September, 1996. Original article submitted May 24, 1946. 相似文献
2.
A.?Serghei L.?Hartmann P.?Pouret L.?Léger F.?KremerEmail author 《Colloid and polymer science》2004,282(8):946-954
Broadband dielectric spectroscopy is employed to study the molecular dynamics in thin polymer layers of (spin-coated) cis-1, 4-polyisoprene (PI) and of (grafted and spin-coated) polydimethylsiloxane (PDMS). For the former, besides the segmental and the normal mode relaxation, a confinement-induced mode is observed, which is assigned to fluctuations of terminal subchains. It turns out that the uptake of water has a strong influence on the dynamics of this relaxation, which takes place in the immediate vicinity of the interface. Between grafted and spin-coated PDMS a pronounced difference in the dynamics is observed for layers that are comparable in thickness to the radius of gyration of the confined chain. This is attributed to the different conformation of grafted and spin-coated polymer layers. 相似文献
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M. Samet G. Boiteux G. Seytre A. Kallel A. Serghei 《Colloid and polymer science》2014,292(8):1977-1988
The dielectric properties of composite materials consisting of a host matrix filled with spherical particles are investigated as a function of frequency by means of numerical calculations. Two different cases are analyzed: (a) composites with a conductive matrix and insulating fillers and (b) composites with an insulating matrix and conductive fillers. In both situations, dielectric dispersions due to interfacial polarization effects are observed in the dielectric spectra. In the present contribution, the characteristic frequencies of interfacial polarization effects are systematically analyzed in dependence on the volume fraction of the spherical fillers and on the conductivity values of the composite phases. The resulting scaling laws are discussed in detail. 相似文献
4.
Kremer F Hartmann L Serghei A Pouret P Léger L 《The European physical journal. E, Soft matter》2003,12(1):139-142
Broadband Dielectric Spectroscopy is employed to study the molecular dynamics in thin layers of grafted and spin-coated polydimethylsiloxane (PDMS) and of the type-A polymer cis-1,4-polyisoprene (PI). Strong resemblance with low-molecular-weight systems is found but additionally the conformation of the chain and its extension becomes important. For PI a confinement-induced relaxation is found. It is observable if the layer thickness is comparable to the end-to-end vector of the chain and it depends strongly on the separation between interfaces. In contrast, the dynamic (and hence the calorimetric) glass transition is not affected by the geometrical confinement.Received: 1 January 2003, Published online: 8 October 2003PACS:
64.70.Pf Glass transitions - 83.10.Mj Molecular dynamics, Brownian dynamics - 68.60.-p Physical properties of thin films, nonelectronic 相似文献
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V. A. Smit S. I. Pogrebnoi Yu. B. Kal'yan M. Z. Krimer 《Russian Chemical Bulletin》1990,39(8):1760-1761
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1934–1935, August, 1990. 相似文献
7.
Nonempirical methods are used to calculate the geometric parameters, the frequencies of normal vibrations, and thermochemical
characteristics of ions existing in saturated vapors over sodium bromide and iodide: Na2X+, NaX2−, Na3X2+, and Na2X3− (X = Br, I). According to the calculations, Na2X+ and NaX2− triatomic ions have a linear equilibrium configuration of D
∞h
symmetry. Pentaatomic ions can exist in the form of three isomers: linear with D
∞h
symmetry, planar cyclic with C
2v
symmetry, and bipyramidal with D
3h
symmetry. At a temperature of ∼1000 K, Na3X2+ and NaX3− pentaatomic ions are shown to be present in vapor mainly in the form of linear isomers. The energies and enthalpies of ion
molecular reactions with the participation of the above ions are calculated, and the formation enthalpies of the ions are
determined, Δ
f
H
o(0 K): 293±2 kJ/mol (Na2Br+), 354±2 kJ/mol (Na2I+), −536±2 kJ/mol (NaBr2−, −458±2 kJ/mol (NaI2−, 24±5 kJ/mol (Na3Br2+, 143±5 kJ/mol (Na3I2+, −810±5 kJ/mol (Na2Br3−, and −675±5 kJ/mol (Na2I3−. 相似文献
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Fatima Yassine Ali Chokr Antoine El Samrani Anatoli Serghei Gisèle Boiteux Mario El Tahchi 《Cellulose (London, England)》2016,23(2):1087-1100
Classical studies concerning “Acetobacter xylinum” focus on bacterial cellulose “BC” yield and rate in broth, after a long period of incubation (7–14 days). Such observations do not highlight bacterial physiology in the first incubation hours and its impact on BC production. In this study, the growth of a wild strain of Acetobacter was monitored in the first incubation hours. We showed the presence of two different physiologies; the first extends from the incubation moment till the formation of a sparse BC. Sparse BC modifies surface viscosity, and stabilizes hydrodynamic conditions to initiate compact BC production that marks the second physiology. Two containers, of different shapes, were used to confirm our findings, one of which is a culture tube with high drift currents on the broth-air interface, and the other is a conical flask with more stable hydrodynamic conditions at the culture’s surface. We showed that Acetobacter always follows two physiologies independent of the container shape. Logistic model, FTIR, XRD and SEM analysis are used to confirm the results. 相似文献