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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Прищепа, Оксана Олеговна, Шабанов, Александр Васильевич, Зырянов, Виктор Яковлевич
Заглавие : Многообразие ориентационных структур в каплях нематических жидких кристаллов и их оптические текстуры
Место публикации : J. Sib. Fed. Univ. Math. Phys. - 2010. - Vol. 3, Is. 3. - P.395-406. - ISSN 1997-1397; Журн. СФУ. Сер. "Математика и физика"
Примечания : Библиогр.: 24
Аннотация: Представлен краткий обзор ориентационных структур в каплях нематических жидких кристал-ов и различных факторов, определяющих специфику их формирования. Основные из этих факторов: соотношение констант упругости жидких кристаллов, размер и форма капель, внешние воздействия (например, электрическое поле) и поверхностное сцепление, определяющее ориентацию молекул нематика на межфазной границе. Подробно рассмотрены особенности структурообразования в капсулированых полимером жидких кристаллах для неоднородных граничных условий.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Сутормин, Виталий Сергеевич, Крахалев, Михаил Николаевич, Зырянов, Виктор Яковлевич
Заглавие : Динамика отклика электрооптической ячейки на основе слоя нематика с управляемым поверхностным сцеплением
Место публикации : Письма в журн. техн. физ. - 2013. - Т. 39, Вып. 13. - С. 1-8
Аннотация: Исследованы электрооптические характеристики ячейки на основе слоя нематического жидкого кристалла, управляемого за счет модификации поверхностного сцепления ионным сурфактантом. Использовалась инверсная мода эффекта, при этом нематик был сориентирован гомеотропно в исходном состоянии и переходил к гибридной гомеопланарной структуре под действием постоянного электрического поля. Рассмотрены зависимости динамических параметров оптического отклика от величины приложенного напряжения.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aver'yanov E. M.
Заглавие : Mean polarizability of molecules and anisotropy of the Lorentz tensor upon a nematic-smectic a phase transition: Their behavior in a homologous series
Место публикации : Russ. J. Phys. Chem. A: MAIK Nauka-Interperiodica / Springer, 2012. - Vol. 86, Is. 5. - P.720-728. - ISSN 0036-0244, DOI 10.1134/S0036024412050044
Примечания : Cited References: 37
Предметные рубрики: CHOLESTERIC LIQUID-CRYSTALS
REFRACTIVE-INDEX DATA
A PHASE
MESOMORPHIC PROPERTIES
ORIENTATIONAL ORDER
OPTICAL ANISOTROPY
LOCAL-FIELD
POLYMORPHISM
TEMPERATURE
A-monotone
Alkyl chain
Experimental values
Homologous series
Homologues
Limiting values
Lorentz
Mesophases
Molecular core
Molecular polarizabilities
Nematic
Orientational order parameters
Polarizabilities
Polarizability density
Quadratic dependence
A-monotone
Smectic
Smectic phase
Smectic phasis
Smectic-A phasis
Ключевые слова (''Своб.индексиров.''): molecular polarizability--anisotropy--phase transition--nematic--smectic--homologues
Аннотация: Experimental values of the mean polarizability of molecules, (gamma) over bar, and components of the Lorentz tensor, L-j, in the nematic and smectic A phases are obtained for a homologous series of n-alkyl-p-(4-ethoxybenzylideneamino)-alpha-methylcinnamates. Dependences of the (gamma) over bar and L-j values on the mesophase temperature, the orientational order parameter S of molecules, and the number n in the homologous series are revealed. The quadratic dependence of (gamma) over bar (S) in the nematic and smectic phases is established that is invariant with respect to the nematic-smectic A transition. Polarizability densities of the molecular core and the alkyl chain are found from the monotone decreasing dependence (gamma) over bar (n)/v (where v is volume per one molecule) in the smectic phase. The presence (or absence) of the odd-even alternation of L-j(n) in the nematic (smectic) phase is shown. A monotone decrease in the Lorentz tensor anisotropy L with an increase in n is revealed in the smectic phase, and limiting values L-j(n - infinity) are determined.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sutormin V. S., Krakhalev M. N., Zyryanov V. Ya.
Заглавие : The dynamics of the response of an electro-optic cell based on a nematic layer with controlled surface anchoring
Место публикации : Tech. Phys. Lett. - 2013. - Vol. 39, Is. 7. - P.583-586. - ISSN 1063-7850, DOI 10.1134/S1063785013070134
Аннотация: We investigate the electrooptical characteristics of a cell based on a nematic liquid crystal layer controlled with the use of modification of the surface anchoring by an ionic surfactant. The inverse mode of the effect is used with the nematic oriented homeotropically in the initial state and transferring to the hybrid homeoplanar structure in an applied dc electric field. We consider the applied voltage dependences of the dynamic parameters of the optical response. В© 2013 Pleiades Publishing, Ltd.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Аверьянов, Евгений Михайлович
Заглавие : Влияние нематического и смектического порядка на поляризуемость молекул жидкого кристалла этил-p-(4-этоксибензилиденамино-)α-метилциннамата
Место публикации : Физ. тверд. тела. - 2013. - Т. 55, вып. 11. - С. 2271-2275. - ISSN 0367-3294
Аннотация: Получены экспериментальные значения компонент тензора поляризуемости gamma молекул жидкого кристалла этил-p-(4-этоксибензилиденамино-)α-метилциннамата в нематической и смектической A фазах. Установлены квадратичные зависимости продольнойϒl и поперечной ϒt компонент, среднего значения Ῡ и анизотропии Δϒ поляризуемости в обеих фазах от параметра ориентационного порядка молекул S при максимально широком интервале изменения S. Фазовый переход нематик-смектик A с непрерывным изменением S проявляется в виде изломов на линейных зависимостях величин Ῡ, Δϒ, ϒl от S[[p]]2[[/p]] и не влияет на зависимость ϒt(S[[p]]2[[/p]]). Дан вывод наблюдаемых зависимостей в рамках теории перехода нематик-смектик A. Выяснены причины различного влияния ориентационного и позиционного упорядочения молекул на параметры поляризуемости.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Аверьянов, Евгений Михайлович
Заглавие : Изменение поляризуемости молекул МВВА при переходе нематик-изотропная жидкость и физические следствия
Место публикации : Физ. тверд. тела. - 2013. - Т. 55, вып. 10. - С. 2020-2025. - ISSN 0367-3294
Аннотация: Получены экспериментальные значения компонент Lj и ϒj тензоров Лорентца и поляризуемости молекул жидкого кристалла 4-метоксибензилиден-4'-бутиланилина (МВВА) в нематической и изотропной фазах. Установлены квадратичные зависимости среднего значения Ῡ(S) и анизотропии Δϒ(S) поляризуемости в нематической фазе от параметра ориентационного порядка молекул S. В рамках феноменологического подхода дан вывод зависимостей Ῡ(S), Δϒ(S) и объяснены их особенности для МВВА и других известных объектов. Выяснена связь зависимостей Ῡ(S), Δϒ(S) с особенностями фазового перехода нематик-изотропная жидкость.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aver'yanov E. M.
Заглавие : Change in the polarizability of MBBA molecules upon the nematic-isotropic liquid transition and physical consequences
Место публикации : Phys. Solid State. - 2013. - Vol. 55, Is. 10. - P.2136-2141. - ISSN 1063-7834, DOI 10.1134/S106378341310003X
Аннотация: The Lorentz tensor components Lj and the polarizability tensor components ?j of 4-methoxyben-zylidene-4?-butylaniline (MBBA) liquid crystal molecules in nematic and isotropic phases have been determined experimentally. The quadratic dependences of the mean value ?(S) and anisotropy ??(S) of the polarizability in the nematic phase on the orientational order parameter S of molecules have been established. Within the phenomenological approach, the dependences ?(S) and ??(S) have been derived, and their features for MBBA and other known objects have been interpreted. The relation of the dependences ?(S) and ??(S) to the features of the nematic-isotropic liquid phase transition has been found. В© 2013 Pleiades Publishing, Ltd.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aver'yanov E. M.
Заглавие : Influence of nematic and smectic orders on polarizability of molecules of ethyl-p-(4-ethoxybenzylideneamino-)alpha-methyl cinnamate liquid crystals
Место публикации : Phys. Solid State: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2013. - Vol. 55, Is. 11. - P.2391-2396. - ISSN 1063-7834, DOI 10.1134/S1063783413110048
Примечания : Cited References: 16
Предметные рубрики: TRANSITION
MBBA
Аннотация: Experimental values of the polarizability tensor gamma components of molecules of ethyl-p-(4-ethoxybenzylideneamino-)alpha-methyl cinnamate liquid crystals in the nematic and smectic A phases have been obtained. Quadratic dependences of the longitudinal, gamma (l) , and transverse, gamma (t) , components, the mean value , and anisotropy Delta gamma in both phases have been established as functions of the orientational order parameter S of molecules in a maximally wide range of S. The nematic-smectic A phase transition with a continuous variation of S manifests itself as kinks in the linear dependences of , Delta gamma, and gamma (l) on S (2) and does not influence the dependence gamma (t) (S (2)). The observed dependences have been derived in the framework of the theory of the nematic-smectic A phase transition. The factors responsible for different influences of the orientational and positional orderings of molecules on the polarizability parameters have been determined.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Parshin A. M., Gunyakov V. A., Zyryanov V. Ya., Shabanov V. F.
Заглавие : Domain structures in nematic liquid crystals on a polycarbonate surface
Место публикации : Int. J. Mol. Sci. - 2013. - Vol. 14, Is. 8. - P.16303-16320. - ISSN 1422-0067, DOI 10.3390/ijms140816303
Ключевые слова (''Своб.индексиров.''): liquid crystal--domain--polymer structure
Аннотация: Alignment of nematic liquid crystals on polycarbonate films obtained with the use of solvents with different solvations is studied. Domain structures occurring during the growth on the polymer surface against the background of the initial thread-like or schlieren texture are demonstrated. It is established by optical methods that the domains are stable formations visualizing the polymer surface structures. In nematic droplets, the temperature-induced transition from the domain structure with two extinction bands to the structure with four bands is observed. This transition is shown to be caused by reorientation of the nematic director in the liquid crystal volume from the planar alignment to the homeotropic state with the pronounced radial configuration of nematic molecules on the surface. The observed textures are compared with different combinations of the volume LC orientations and the radial distribution of the director field and the disclination lines at the polycarbonate surface.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Loiko V. A., Zyryanov V. Ya., Maschke U., Konkolovich A. V., Miskevich A. A.
Заглавие : Small-angle light scattering and transmittance of polymer film, containing liquid crystal droplets with inhomogeneous boundary conditions
Коллективы : Conference on Electromagnetic and Light Scattering (13; 2011 ; Sept. ; 26-30; Taormina, Italy)
Место публикации : J. Quant. Spectrosc. Radiat. Transf.: Pergamon-Elsevier Science Ltd, 2012. - Vol. 113, Is. 18. - P.315-322. - ISSN 0022-4073, DOI 10.1016/j.jqsrt.2012.03.026
Примечания : Cited References: 28
Предметные рубрики: NEMATIC DROPLETS
Ключевые слова (''Своб.индексиров.''): liquid crystals--light scattering--soft matter--composite materials--polymer-dispersed liquid crystal films
Аннотация: Light scattering by a monolayer of oriented liquid crystal (LC) droplets in polymer matrix is considered. A method for modeling transmittance and angular distribution of scattered light by a monolayer of LC droplets with cylindrical symmetry of the director configuration is developed. It is based on the anomalous diffraction and interference approximations. The internal structures of nematic LC droplets are calculated on base of the free energy minimization problem solution using the relaxation method. The results for monolayers of spherical LC droplets with homogeneous and inhomogeneous boundary conditions are obtained. It is shown that for monolayers containing droplets with inhomogeneous boundary conditions of the "tangential-normal" type there is an asymmetry of the angular structure of the transmitted light over the polar angle. (c) 2012 Elsevier Ltd. All rights reserved.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Loiko V. A., Zyryanov V. Ya., Konkolovich A. V., Misckevich A. A., Krakhalev M. N., Maschke U.
Заглавие : Investigation of transmittance and small-angle light scattering by monolayer of liquid crystal droplets with modified boundary conditions
Коллективы : International Topical Meeting: Optics of Liquid Crystals (14th; Sept 25 - Oct 1, 2011; Yerevan, Armenia)
Место публикации : Mol. Cryst. Liquid Cryst. - 2012. - Vol. 561, Is. 1. - P.194-202. - ISSN 1542-1406, DOI 10.1080/15421406.2012.687237
Примечания : Cited References: 24
Предметные рубрики: NEMATIC DROPLETS
ANOMALOUS DIFFRACTION
APPROXIMATION
FILM
Ключевые слова (''Своб.индексиров.''): light modulation--light scattering--polymer dispersed liquid crystal--optical transmittance
Аннотация: A numerical method for modelling transmittance and angular distribution of light scattered by a Polymer Dispersed Liquid Crystal (PDLC) film, containing droplets with inhomogeneous boundary conditions, is proposed. It is based on the anomalous diffraction approximation and an interference approximation. The internal structures of nematic LC droplets are calculated on the basis of the free energy minimization problem solution using the relaxation method. The results for a monolayer of spherical LC droplets with modified boundary conditions caused by the local increase of the concentration of surface-active ions at the polymer-LC interface are discussed.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Parshin A. M., Nazarov V. G., Zyryanov V. Ya., Shabanov V. F.
Заглавие : Magnetic-field-induced structural transition in polymer-dispersed liquid crystals
Место публикации : Mol. Cryst. Liquid Cryst. - 2012. - Vol. 557, Is. 1. - P.50-59. - ISSN 1542-1406, DOI 10.1080/15421406.2011.632237
Примечания : Cited References: 19. - This study was supported by the Presidium of the Russian Academy of Sciences (Project no. 24.1) and the Siberian Branch of the Russian Academy of Sciences (grant no. 43).
Предметные рубрики: FRANK CONSTANTS
ELECTRIC-FIELD
NEMATIC DROPS
ANISOTROPY
ALIGNMENT
FILMS
ORDER
Ключевые слова (''Своб.индексиров.''): anchoring energy--magnetic field--polymer-dispersed liquid crystals--structural transition--temperature fluctuations
Аннотация: The structural transition occurring in droplets of nematic liquid crystals formed in a polymer in magnetic field is studied. The transition is caused by field-driven weakening of tangential surface anchoring and develops following two scenarios: bipolar structure/homogeneous structure or bipolar structure/radial structure. The first scenario suggests a cyclic transition occurring upon thermal fluctuations without field. The structural transition is considered within a model of the biaxial liquid crystal/polymer interface. The model describes tendency of the nematic director to align tangentially on a droplet's surface, normally under the action of flexoelectric polarization, and axially along the magnetic-field-imposed easy orientation axis.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sutormin V. S., Крахалев, Михаил Николаевич, Prishchepa O. O., Zyryanov V. Ya.
Заглавие : Electrically controlled local Frédericksz transition in a layer of a nematic liquid crystal
Место публикации : JETP Letters. - 2012. - Vol. 96, Is. 8. - P.511-516. - ISSN 0021-3640, DOI 10.1134/S0021364012200131
Примечания : Cited References: 18. - This work was supported by the Russian Foundation for Basic Research (project nos. 12-03-00816, 12-02-31613, and 12-03-31144); by the Presidium of the Russian Academy of Sciences (project nos. 24.29 and 24.32); by the Siberian Branch, Russian Academy of Sciences (project nos. 30 and 101); and by the Ministry of Education and Science of the Russian Federation (state contract no. 14.V37.21.0730, federal program "Human Capital for Science and Education in Innovative Russia").
Предметные рубрики: ANCHORING TRANSITIONS
INTERFACE
ORIENTATION
SURFACES
Аннотация: A local Frédericksz transition caused by electrically controlled surface anchoring in a nematic liquid crystal has been implemented owing to the displacement of surface-active ions. In the initial case, the nematic is homeotropically aligned by monomolecular layers of cetyltrimethylammonium bromide cations adsorbed on the surface of substrates. One of the substrates in a static electric field becomes free of a cation layer and specifies planar boundary conditions; as a result, a homeoplanar orientation structure is formed. The features of the dynamics of the optical response of the cell under study that are characteristic of the effect under consideration are discussed.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Timofeev I. V., Lin Y. T., Gunyakov V. A., Myslivets S. A., Arkhipkin, V. G., Vetrov S. Y., Lee W., Zyryanov V. Ya.
Заглавие : Voltage-induced defect mode coupling in a one-dimensional photonic crystal with a twisted-nematic defect layer
Место публикации : Phys. Rev. E: American Chemical Society, 2012. - Vol. 85, Is. 1. - Ст.11705. - ISSN 1539-3755, DOI 10.1103/PhysRevE.85.011705
Примечания : Cited References: 39. - This work was supported in part by DSP Grant No. 2.1.1/3455; RAS Grants No. 3.9.1 and No. 21.1, SB RAS Grants No. 5 and No. 144, and by the National Science Council of Taiwan under Grant No. NSC 98-2923-M-033-001-MY3.
Предметные рубрики: LIQUID-CRYSTAL
REFLECTION SPECTRUM
OPTICAL-PROPERTIES
ANISOTROPIC MEDIA
ELECTRIC-FIELD
EIGENVALUES
ORIENTATION
Аннотация: Defect modes are investigated in a band gap of an electrically tunable one-dimensional photonic crystal infiltrated with a twisted-nematic liquid crystal. Their frequency shift and interference under applied voltage are studied both experimentally and theoretically. We deal with the case where the defect layer thickness is much larger than the wavelength (i.e., the Mauguin condition). It is shown theoretically that the defect modes could have a complex structure with elliptic polarization. Two series of polarized modes are coupled with each other and exhibit an avoided crossing phenomenon in the case of opposite parity.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Sutormin V. S., Krakhalev M. N., Prishchepa O. O., Lee W., Zyryanov V. Ya.
Заглавие : Electro-optical response of an ionic-surfactantdoped nematic cell with homeoplanar-twisted configuration transition
Коллективы : Russian Foundation for Basic Research [12-03-00816]; Siberian Branch of the Russian Academy of Sciences (SB RAS) [30, 24.32]; Ministry of Science and Technology of Taiwan through an NSC-SB-RAS joint project [NSC 103-2923-M-009-003-MY3]
Место публикации : Opt. Mater. Express: Optical Society of America, 2014. - Vol. 4, Is. 4. - P.810-815. - ISSN 2159-3930, DOI 10.1364/OME.4.000810
Примечания : Cited References: 16. - This work was partially supported by the Russian Foundation for Basic Research (project No. 12-03-00816), and by the Siberian Branch of the Russian Academy of Sciences (SB RAS) through Grants Nos. 30, 24.32, and by the Ministry of Science and Technology of Taiwan under Grant No. NSC 103-2923-M-009-003-MY3 through an NSC-SB-RAS joint project.
Предметные рубрики: LIQUID-CRYSTAL
ORIENTATION
SURFACES
LAYER
Аннотация: This study is concerned with the optical response of an electro-optical material consisting of nematic liquid crystal as well as ionic surfactant as a dopant. The dopant is a key component to carry out the working of the resulting device through configuration switching. The operational principle is based on the surface anchoring transition induced by a steady electric field. The dynamic characteristics of the electro-optical cell can be considerably improved when the nematic layer is reoriented from the initially homeoplanar director configuration into the twisted state. Besides, a method to shorten the relaxation time is demonstrated by using a controlling pulse with a bipolar waveform. (C)2014 Optical Society of America
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aver'yanov E. M.
Заглавие : Orientational order and polarizability of molecules in a nematic liquid crystal
Место публикации : Phys. Solid State. - 2014. - Vol. 56, Is. 5. - P.1058-1063. - ISSN 1063-7834, DOI 10.1134/S1063783414050035
Примечания : Cited References: 17
Предметные рубрики: NORMAL-BUTYLANILINE MBBA
INTERNAL-ROTATION
TRANSITION
PHASE
Аннотация: The influence of the orientational order of molecules in a nematic liquid crystal on the mean value ?? and anisotropy ?? of the molecular polarizability has been studied in the framework of the molecular statistical approach with allowance for the perturbation of the electronic structure of molecules due to the change in the conformation of their aromatic core and intermolecular interactions. Experimental dependences of ?? and ?? on the molecular orientational order parameter S have been derived, and their specific features for the known objects have been explained. The possibility of separating the contributions of opposite signs to the dependence ??(S) due to the change in the conformation of molecules and intermolecular interactions has been shown using nematic MBBA as an example. © 2014 Pleiades Publishing, Ltd.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Parshin A. M., Gunyakov V. A., Zyryanov V. Ya., Shabanov V. F.
Заглавие : Electric and magnetic field-assisted orientational transitions in the ensembles of domains in a nematic liquid crystal on the polymer surface
Коллективы : Russian Foundation for Basic Research [12-03-00816]; Siberian Branch of the Russian Academy of Sciences (SB RAS) [30, 24.29, 24.32]; SB RAS through a Taiwan-SB-RAS joint project
Место публикации : Int. J. Mol. Sci. - 2014. - Vol. 15, Is. 10. - P.17838-17851. - ISSN 1422-0067, DOI 10.3390/ijms151017838
Примечания : Cited References: 21. - This work was partially supported by the Russian Foundation for Basic Research (project No. 12-03-00816), and by the Siberian Branch of the Russian Academy of Sciences (SB RAS) through Grants Nos. 30, 24.29, 24.32, and by SB RAS through a Taiwan-SB-RAS joint project.
Предметные рубрики: FRANK CONSTANTS
INTERFACE
ALIGNMENT
DISCLINATIONS
STABILITY
COATINGS
DIRECTOR
Ключевые слова (''Своб.индексиров.''): liquid crystal--polycarbonate--domain structure--electric field--magnetic field
Аннотация: Using electro- and magneto-optical techniques, we investigated orientational transitions in the ensembles of domains in a nematic liquid crystal on the polycarbonate film surface under the conditions of competing surface forces that favor radial and uniform planar alignment of nematic molecules. Having analyzed field dependences of the intensity of light passed through a sample, we established the threshold character of the orientational effects, plotted the calculated intensity versus magnetic coherence length, and compared the latter with the equilibrium length that characterizes the balance of forces on the polymer surface.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aver'yanov E. M.
Заглавие : Structural and thermodynamic consequencies of the interaction of conformational degrees of freedom of azomethines in the nematic phase
Место публикации : J. Struct. Chem.: Springer, 2014. - Vol. 55, Is. 4. - P.605-611. - ISSN 0022-4766, DOI 10.1134/S0022476614040039. - ISSN 1573-8779
Примечания : Cited References: 21
Предметные рубрики: CONJUGATED POLY(AZOMETHINE)S
TERMINAL SUBSTITUENTS
ELECTRONIC-STRUCTURES
FLUORINATED ANALOGS
INTERNAL-ROTATION
MOLECULES
COMPOUND
ANGLES
STATE
NMR
Ключевые слова (''Своб.индексиров.''): azomethines--benzylideneaniline--conformation--steric effects of substituents--nematic-isotropic liquid transition--conformational polymorphism
Аннотация: The interaction of the conformational degrees of freedom of azomethines in the nematic phase, which is induced by electronic donor-acceptor properties of the terminal substituents of the benzylideneaniline core is studied. These degrees of freedom related to the rotation angles phi (k) around the bonds between the substituent and the aniline ring (phi(1)) and also between the CH=N bridge and the aniline ring (omega(2)) are characterized by the parameters Q (k) = aOE (c) cos(2)phi (k) . It is found that the interaction of these degrees of freedom is manifested in the linear dependence Q (2)(Q (1)). Within the phenomenological theory the effect of this interaction on changes delta (k) in the Q (k) values during the nematic liquid crystal-isotropic liquid phase transition is revealed along with the temperature T (NI) and character of this transition. The derivation of previously established empirical dependences T (NI)(Q (k) ) is presented in the presence of direct and indirect steric effects of side substituents affecting the Q (k) values. A diverse combination of delta (k) signs in the nematic phase, which is a prerequisite for the conformational polymorphism of the nematic phases of azomethines, is shown.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aver'yanov E. M.
Заглавие : Spectral properties of calamitic and discotic nematics, associated with the difference in their local symmetry
Место публикации : Journal of Optical Technology (A Translation of Opticheskii Zhurnal). - 1998. - Vol. 65, Is. 7. - P.515-523. - ISSN 1070-9762
Ключевые слова (''Своб.индексиров.''): crystal symmetry--light absorption--light polarization--resonance--calamitic nematics--discotic nematics--nematic liquid crystals
Аннотация: This paper discusses how the features of the local symmetry of calamitic and discotic nematic liquid crystals, the orientational ordering of the molecules, the polarization of intramolecular transitions, and the resonance intermolecular interactions (local-field effects) affect the polarized absorption spectra of these objects. It is shown that the difference of the local symmetry of calamitic and discotic nematics manifests itself in observable qualitative differences in their spectral properties. The published (controversial) experimental data are explained. В© 1998 The Optical Society of America.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Parshin A. M., Zyryanov V. Ya., Shabanov V. F.
Заглавие : The director field distribution with the strongly pinned alignment in nematic structures at the polymer surface
Коллективы : Russian Foundation for Basic Research [12-03-00816], Siberian Branch ofthe Russian Academy of Sciences (SB RAS) [30, 24.29, 24.32], SB RASthrough a Taiwan-SB RAS joint project
Место публикации : Liq. Cryst.: Taylor & Francis, 2015. - Vol. 42, Is. 1. - P.57-64. - ISSN 0267, DOI 10.1080/02678292.2014.960904. - ISSN 13665855(eISSN)
Примечания : Cited References:18. - This work was partially supported by the Russian Foundation for BasicResearch [project No. 12-03-00816] and by the Siberian Branch of theRussian Academy of Sciences (SB RAS) [grants nos. 30, 24.29, 24.32] andby SB RAS through a Taiwan-SB RAS joint project.
Предметные рубрики: LIQUID-CRYSTALS
DISCLINATION LINES
DEFECTS
Ключевые слова (''Своб.индексиров.''): orientational order--disclination--adsorption--nematic--polymer surface--director configuration
Аннотация: We investigate orientational nematic liquid crystal structures that form at the polymer surface due to adsorption, their stability against the schlieren texture and features of point and linear singularities in them. We demonstrate that surface disclination lines, which also occur due to molecular adsorption, can lead to azimuthal anchoring of a bulk layer and make the singularities with the charge m=+/- 1 stable. We consider the director field distribution in a nematic layer as a result of the combination of two aligning factors, which are the linear disclination that tend to impose uniform planar ordering and point defects that impart the radial configuration to the director. With the use of the calculation, we analyse the energies of elastic distortions of the director field for the radial-planar, radial-homeotropic and radial-radial configurations, depending on the nematic layer thickness.
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