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31.
Yu. N. Sazanov L. A. Shibaev N. G. Stepanov T. M. Bulina E. F. Kolpikova A. S. Fialkov A. A. Boiko 《Journal of Thermal Analysis and Calorimetry》1989,35(5):1365-1371
Mass-spectrometric thermal analysis of samples of furan polymers obtained by heating furyl alcohol in a closed volume at 200 °C, 250 °C and 300 °C permitted determination of the qualitative composition of the gas products evolved from the polymers upon non-isothermal temperature increase from 20 to 1200 °C. The degree of unsaturation of the samples was evaluated quantitatively. The main features of the formation, degradation, structurization and carbonization of furan polymers were considered. 相似文献
32.
B. A. Zhubanov R. F. Mukhamedova G. I. Boiko T. P. Maimakov N. P. Lyubchenko K. B. Erzhanov 《Russian Journal of Applied Chemistry》2008,81(3):506-508
Procedures for esterification of biologically active mono-and bispiperidols by reactions with benzoyl and terephthaloyl chlorides were developed. 相似文献
33.
V. I. Boiko V. V. Evstigneev N. N. Prilepskikh I. V. Shamanin 《Russian Physics Journal》1986,29(6):437-440
Relations describing the process of heat transfer from the energy-dissipation region of a monoenergetic ion beam in an obstructing target within the pulse duration are derived on the basis of an analysis of the fundamental laws governing the interaction of a high-intensity ion beam with condensed media and the solution of the heat-conduction equation. The proposed analytical expressions can be used to assess the feasibility of neglecting thermal conductivity and calculating the temperature fields in the target without solving the heat-conduction boundary-value problem, namely on the basis of the characteristics of a heat-release source approximating the real source.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 16–20, June, 1986. 相似文献
34.
Specific features of the melting of PET samples with different molecular masses after their thermal and mechanical treatment
(orientational drawing) are studied by the DSC method. Orientational drawing of the samples leads to the development of a
supermolecular structure, which depends on the molecular mass and thermal prehistory of the initial samples. 相似文献
35.
36.
ABSTRACTHigh sensitivity of liquid crystals to the electric field makes them highly demanded and widely used in different applications. Despite the large number of the electro-optical research on the low-molar-mass liquid crystals electro-optics of the liquid crystalline (LC) polymers is much less studied. Herein, the comparative electro-optical behaviour of two nematic comb-shaped polyacrylates with phenylbenzoate mesogenic side groups was studied in detail. These two polyacrylates have completely the same structure of polymer backbone and spacer length but different in the direction of the ester group in the phenylbenzoate fragments. It was found that this difference predetermines their completely opposite electro-optical properties.The influence of the electric field of different strength and frequency on the orientation of the mesogenic groups of these polymers is studied. It is shown that application of the electric field at temperatures above the glass transition temperature (~25°C) induces reorientation of the mesogenic groups along or perpendicular to the electric field direction depending in its turn on the ester group direction. For one of the polyacrylates an unusual textural transition is found; during cooling of the polymer sample under applied field at definite temperature a sharp change in the mesogen’s orientation from homeotropic to planar one is found. This electro-optical phenomenon is observed for the first time and probably associated with sharp change in sign of anisotropy of dielectric permittivity from positive (at high temperatures) to negative one (at lower temperatures). Kinetics of the electro-optical switching at different temperatures, influence of the molar masses of the polymer and frequency of the applied AC field on electro-optical behaviour of the polymers are studied. The possibility of the fixation of the electroinduced homeotropic alignment of the mesogenic groups by photopolymerisation of the diacrylate dissolved in the polymer is demonstrated. 相似文献
37.
The method proposed in [1, 2] is used to construct an analytic solution of the problem of two incompressible plates propelled by the explosion products of a condensed explosive. A solution of the problem by the classical methods of the gas dynamics of a perfect gas with =3 was previously obtained in [3]. However, the analysis carried out in [3] does not reproduce the entire wave configuration which may result from the interaction of expansion waves with moving plates and is limited to the study of the flow configuration realized in the case of single reflection of the waves from the plate contact boundary. This leads to overestimation of the limiting projection velocities when the relative masses of the plates are greater than unity.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 148–152, March–April, 1991. 相似文献
38.
39.
Based on fine measurement of time-averaged data of hot-wire anemometer we have developed the method determining local values
of skin-friction coefficient in the vicinity of the wall on the planar porous surface at the flow past which the noncanonical
turbulent boundary layer is formed. The method may be applied at investigation of the efficiency of various effects on the
incompressible boundary layer, in particular, with microblowing of air where usage of direct methods of friction determination
is complicated. 相似文献
40.
Acoustical Physics - For samples of screens made in the form of a steel layer with an overlying stack of rubber layers with cylindrical voids, the reflection and transmission coefficients are... 相似文献