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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Гардымова, Анна Петровна, Тихонов, Алексей Яковлевич, Зырянов, Виктор Яковлевич
Заглавие : Оптическая мультистабильность в композиционном материале на основе полимера, жидкого кристалла и ионного сурфактанта при воздействии электрического поля
Место публикации : Перспективные материалы. - Москва: Общество с ограниченной ответственностью "Интерконтакт Наука", 2011. - № 4. - С. 32-35. - ISSN 1028-978X
Ключевые слова (''Своб.индексиров.''): cholesteric liquid crystal--polymer--ionic surfactant--optical multistability--холестерический жидкий кристалл--полимер--ионный сурфактант--оптическая мультистабильность
Аннотация: Разработан композиционный материал на основе полимера, жидкого кристалла (ЖК) и ионного сурфактанта, характеризующийся оптической мультистабильностью и механической гибкостью. Оптические свойства данного материала варьируются за счет переключения капель холестерического ЖК между различными структурными состояниями, остающимися стабильными после выключения управляющего электрического сигнала. Функциональным инструментом для управления ориентационной структурой капель холестерика внешним электрическим полем является наноразмерный слой ионного сурфактанта. Подобраны параметры электрических сигналов, переключающих капли в новые стабильные состояния, а также возвращающих их в исходную радиальную структуру.A composite material based on polymer, liquid crystal and ionic surfactant is developed, which is characterized by the optical multistability and mechanical flexibility. Optical properties of the material are varied by switching the cholesteric droplets between different structural states remaining stable after breaking the control electrical signal. Functional tool to control the orientational structure of cholesteric droplets by an external electric field is a nanosized layer of ionic surfactant. The parameters of electrical signals switching the droplets in new stable states and returning them in the initial radial structure are chosen.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Морозов, Евгений Владимирович, Больбасов Е. Н., Горенинский С. И., Юрков Г. Ю., Бузник, Вячеслав Михайлович
Заглавие : МРТ исследование процессов замерзания воды и таяния льда в полимерных композиционных мембранах
Место публикации : Полимер. матер. и технол. - 2020. - Т. 6, № 4. - С. 20-29. - ISSN 2415-7260, DOI 10.32864/polymmattech-2020-6-4-20-29
Примечания : Библиогр.: 23
Аннотация: Полимерные композиционные мембраны, полученные методом электроформования, находят широкое применение в различных отраслях промышленности благодаря своей структуре и уникальным свойствам. Однако, вследствие высокой сорбционной активности изделия на основе таких мембран подвержены негативному влиянию атмосферной влаги в условиях знакопеременного температурного воздействия. В данной работе представлены новые полимерные композиционные мембраны с улучшенными водоотталкивающими свойствами, сочетающие слои гидрофобных и гидрофильных волокнистых материалов. Впервые проведены МРТ исследования процессов замерзания воды и таяния льда в них. Детально изучены качественная и количественная стороны протекающих процессов. Обнаружено, что водопоглощение в композиционных мембранах осуществляется исключительно за счет слоев гидрофильного материала. Исследование также показало, что скорость протекания процессов замерзания/таяния оказалась чувствительна к присутствию гидрофобных слоев: обнаружено, что введение слоев гидрофобных волокон в композит приводит к существенному снижению скорости замерзания и таяния. Полученный результат демонстрирует возможности метода МРТ для исследования и диагностики полимерных волокнистых материалов и процессов замерзания/таяния в них, а также показывает пути оптимизации свойств готовых полимерных материалов для арктических и иных практических приложений.Electrospun polymer composite membranes are very attractive for many industrial applications due to their special structure and properties. However, high sorption capacity of fibrous material results in noticeable moisture content in the membranes which then, being exposed to natural environment, suffer from the freeze/thawing cycling. In this work, the new polymer composite membranes with advanced water resistance due to a layered hydrophobic/hydrophilic structure were manufactured via electrospinning. Using these membranes the NMR imaging study of water freezing and ice thawing were carried out for the first time. In result, the qualitative and quantitative character of the processes was elucidated. Thus, it was found out that the water uptake in membranes occurs solely due to the hydrophilic layers. From the other hand, the hydrophobic layers play a major role, affecting the rate of freeze/thawing: introduction the hydrophobic material into membranes structure makes the freeze/thawing front propagation slow down. The results obtained demonstrate the advantages of the NMR imaging as a tool for studying and control of the polymer fibrous materials, processes of water sorption and water freezing/thawing occurring under the natural environment conditions. New results also show the routes of polymer materials optimization for arctic and other practical applications.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Аверьянов, Евгений Михайлович
Заглавие : Эффективные диэлектрическая проницаемость и показатель преломления квазидвумерной полидоменной пленки сопряженного полимера в области поглощения света
Место публикации : Жидк. крист. и их практич. использ. - 2023. - Т. 23, № 2. - С. 81-89. - ISSN 19913966 (ISSN), DOI 10.18083/LCAppl.2023.2.81; Liq. Cryst. Appl. - ISSN 24999644 (eISSN)
Примечания : Библиогр.: 15
Аннотация: Рассматривается одноосная пленка сопряженного полимера в плоскости XY с оптической осью Z, состоящая из статистически эквивалентных одноосных доменов среднего размера a. Оптические оси доменов nd хаотично ориентированы в плоскости XY. В области поглощения света домены характеризуются диэлектрическими проницаемостями εj = ε1j + iε2j и показателями преломления Nj = nj + ikj для обыкновенной (j = о) и необыкновенной (j = е) световых волн. Для волн с длиной λ ˃˃ a, волновым вектором k*⊥Z и поляризацией E⊥Z такая пленка является двумерной композитной средой с эффективной диэлектрической проницаемостью ε* = ε1 + iε2 и эффективным показателем преломления N* = n* + ik*. В данной работе получены соотношения, связывающие компоненты ε1*, ε2*, n*, k* с компонентами nj, kj. Для проверки этих соотношений и расчета компонент ε1*, ε2*, n*, k* вместо величин no, ko (ne, ke) использовались экспериментальные значения noA, koA (neA, keA) в областях прозрачности и электронного поглощения для одноосных монодоменных пленок сопряженного полимера F8BT с аксиальной ориентацией (OА) макромолекул относительно оптической оси nA в плоскости XY. Рассчитанные компоненты ε1*, ε2*, n*, k* сравнивались с экспериментальными значениями компонент ε1oP, ε2oP, noP, koP в тех же спектральных областях для обыкновенной световой волны с λ ˃˃ a, k*⊥Z и поляризацией E⊥Z в одноосных полидоменных пленках F8BT с плоскостной ориентацией (OP) макромолекул. Соотношения ε1* ≈ ε1oP, ε2* ≈ ε2oP, n* ≈ noP, k* ≈ koP, установленные здесь с хорошей точностью, показывают близость полидоменных пленок F8BT к идеальному двумерному поликристаллу.An uniaxial film of a conjugated polymer consisting of statistically equivalent uniaxial domains of the average dimension a is considered in the plane XY with the optical axis Z. The optical axes nd of domains are randomly oriented in the plane XY. In the region of light absorption, the domains are characterized by the dielectric constants εj = ε1j + iε2j and the refractive indices Nj = nj + ikj for an ordinary (j = о) and extraordinary (j = е) light waves. For the waves with wavelength λ ˃˃ a, wave vector k*⊥Z and polarization E⊥Z, such polydomain film is two-dimensional composite medium with effective dielectric constant ε* = ε1 + iε2 and effective refractive index N* = n* + ik*. In this work, the relations which connect the components ε1*, ε2*, n*, k* with the components nj, kj were established. For testing the relations and calculating the components ε1*, ε2*, n*, k*, the experimental values noA, koA (neA, keA) were used instead of values no, ko (ne, ke) in the transparency and electronic absorption regions for the uniaxial monodomain films of the conjugated polymer F8BT with axial orientation (OА) of macromolecules with respect to the optical axis nA in the XY plane. The calculated components ε1*, ε2*, n*, k* were compared with the experimental components ε1oP, ε2oP, noP, koP in the same spectral regions for an ordinary light wave with λ ˃˃ a, k*⊥Z, E⊥Z in the uniaxial polydomain F8BT films with in-plane orientation (OP) of macromolecules. The relations ε1* ≈ ε1oP, ε2* ≈ ε2oP, n* ≈ noP, k* ≈ koP established here with good precision show that the polydomain F8BT films are close to the ideal two-dimensional polycrystal.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Аверьянов, Евгений Михайлович
Заглавие : Оптическая анизотропия и ориентационный порядок одноосных пленок сопряженных полимеров
Место публикации : Жидк. кристаллы и их практич. использ. - 2020. - Т. 20, № 1. - С. 53-63. - ISSN 1991-3966, DOI 10.18083/LCAppl.2020.1.53; Liq. Cryst. Appl.
Примечания : Библиогр.: 14
Аннотация: Для одноосной пленки сопряженного полимера с макромолекулами в виде наборов субъединиц разной длины установлена связь компонент e(1,2)j(w) диэлектрической функции ej(w) = e1j(w) + ie2j(w) с параметром ориентационного порядка s дипольных моментов молекулярных переходов, отвечающих изолированной полосе поглощения света c поляризацией вдоль (j = || ) и нормально (j =. ) оптической оси пленки. Новые методы определения s реализованы для пленки полимера P3OT с плоскостной ориентацией субъединиц и известными зависимостями e(1,2)j(w) в областях прозрачности и низкочастотного электронного поглощения. Учтена анизотропия компонент fj(w) = 1 + Lj[ej(w) - 1] тензора локального поля. Экспериментальные значения компонент Lj тензора Лорентца для пленки P3OT определены с использованием зависимостей e1j(w) в видимой области прозрачности. Показано совместное влияние длины и ориентационного порядка субъединиц, а также динамических диполь-дипольных взаимодействий между субъединицами (эффектов локального поля) на положение максимумов полос e2j(w).The uniaxial film of conjugated polymer with macromolecules as a set of subunits of different lengths was studied. For this film, the connection between the components e(1,2)j(w) of the dielectric function ej(w) = e1j(w) + ie2j(w) and the orientation order parameter s was established. The orientation order parameter s of the dipole moments of molecular transitions corresponds to an isolated absorption band of light with polarization along (j = ||) and across (j =. the optical axis of the film. New methods have been implemented for determining s of the P3OT polymer film. The P3OT polymer film is characterized by a planar orientation of subunits and known dependences e(1,2)j(w) in the regions of transparency and low-frequency electron absorption. The anisotropy of the components fj(w) = 1 + Lj[ej(w) - 1] of the local-field tensor was taken into account. The experimental values of the components Lj of the Lorentz tensor for the P3OT film were determined using the dependences e1j(w) in the visible transparency region. The combined effect of the length and orientation order of the subunits, as well as dynamic dipole-dipole interactions between subunits (local-field effects) on the position of the maxima of the e2j(w) bands was shown.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Аверьянов, Евгений Михайлович
Заглавие : Молекулярно-оптическая и структурная анизотропия одноосных монодоменных/полидоменных пленок сопряженного полимера F8BT с аксиальной/плоскостной ориентацией макромолекул
Место публикации : Жидк. крист. и их практич. использ. - 2023. - Т. 23, № 1. - С. 68-77. - ISSN 19913966 (ISSN), DOI 10.18083/LCAppl.2023.1.68; Liq. Cryst. Appl. - ISSN 24999644 (eISSN)
Примечания : Библиогр.: 14
Аннотация: На практике используются одноосные полимерные пленки двух типов: монодоменные пленки на ориентирующих подложках с аксиальной ориентацией макромолекул относительно оптической оси пленки n, параллельной плоскости подложки (тип ОА); полидоменные пленки на изотропных подложках с плоскостной ориентацией макромолекул и оптической осью n, нормальной к подложке (тип ОP). Молекулярно-оптическая анизотропия пленки определяется средней по ансамблю анизотропией δγ = γ|| – γ⊥ компонент поляризуемости γj мономерных звеньев полимерных цепей для поляризаций световой волны вдоль (j = ||) и нормально (j = ⊥) оси n. Структурную анизотропию пленки описывают параметры ориентационного порядка U дипольных моментов m электронных (колебательных) переходов в мономерных звеньях макромолекул относительно оси n. Для пленок одного полимера значения параметров Rδ(λ) = δγА/δγP и RU = UA/UP характеризует степень близости полидоменной пленки к идеальному двумерному поликристаллу. В данной работе исследованы зависимость Rδ(λ) от длины световой волны λ в видимой области прозрачности и параметры порядка UA(P) для дипольного момента длинноволнового электронного перехода в монодоменных и полидоменных пленках сопряженного полимера F8BT. Значения Rδ(λ) получены из показателей преломления пленок nj(λ) с учетом компонент fj(λ) = 1 + Lj[nj2(λ) – 1] тензора локального поля. Компоненты Lj тензора Лорентца определены с использованием зависимостей nj(λ). Значения Rδ(λ) согласуются с Rδ = –2 для двумерного поликристалла, состоящего из одноосных кристаллитов. Параметры UA(P) определены с использованием фоновых величин nbj и максимальных значений kjmax компонент комплексного показателя преломления Nj(λ) = nj(λ) + ikj(λ) пленок в области длинноволновой полосы электронного поглощения при учете фоновых значений fbj = 1 + Lj(nbj2 – 1). Экспериментальное значение RU отличается от RU = –2 для двумерного поликристалла, что показывает чувствительность параметра UP к ориентационному беспорядку мономерных звеньев макромолекул в междоменных областях полидоменных пленок.Two types of uniaxial polymer films are used in practice. The first type is singledomain film on orienting substrate with axial orientation of macromolecules with respect to the optical axis of the film n which is parallel to the substrate plane (type ОА). The second type is polydomain film on isotropic substrate with in-plane orientation of macromolecules and the optical axis of the film n which is perpendicular to the substrate plane (type ОP). The molecular-optical anisotropy of a film is defined by the ensemble-averaged anisotropy δγ = γ|| – γ⊥ of the components γj of the polarizability of the monomer units of a polymer for the light-wave polarizations along (j = ||) and across (j = ⊥) the optical axis n. The structural anisotropy of the film is described by the orientation order parameters U of the dipole moments m of the electronic (oscillatory) transitions in monomer units of macromolecule with respect to axis n. For films of the same polymer, the values of Rδ(λ) = δγА/δγP and RU = UA/UP characterize the closeness degree of the polydomain film to the ideal twodimensional polycrystal. In this work, the dependence Rδ(λ) on the light-wavelength λ in the visible range and the order parameters UA(P) for the dipole moment of the long-wavelength electronic transition in single-domain and polydomain films of the conjugated polymer F8BT were studied. The values Rδ(λ) were determined from the refractive indices nj(λ) of the films with the local-field tensor components fj(λ) = 1 + Lj[nj2(λ) – 1]. The Lorentz-tensor components Lj were obtained using the dependences nj(λ). The values Rδ(λ) are in agreement with Rδ = –2 for two-dimensional polycrystal consisted of the uniaxial crystallites. The parameters UA(P) were determined with the use of the background values nbj and maximal values kjmax of the components of the complex refractive indices Nj(λ) = nj(λ) + ikj(λ) of the films in the region of their long-wavelength electronic absorption band, taking into account the background values fbj = 1 + Lj(nbj2 – 1). The experimental value RU differs from RU = –2 for two-dimensional polycrystal. This difference reveals the sensitivity of the parameter UP to the orientation disorder of the monomer units of macromolecules in interdomain regions of polydomain films.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zobov V. E., Popov M. A.
Заглавие : Tree growth parameter in the Eden model on face-centered hypercubic lattices
Место публикации : Theor. Math. Phys. - 2005. - Vol. 144, Is. 3. - P.1361-1371. - ISSN 0040-5779, DOI 10.1007/s11232-005-0165-z
Примечания : Cited References: 19
Предметные рубрики: BRANCHED POLYMERS
HIGH-TEMPERATURES
EXPANSION
CLUSTERS
SYSTEMS
TIME
Ключевые слова (''Своб.индексиров.''): eden model--number of lattice trees--monte carlo method--growth parameter--singular points of generating function--large-dimension expansion--face-centered hypercubic lattice--eden model--face-centered hypercubic lattice--growth parameter--large-dimension expansion--monte carlo method--number of lattice trees--singular points of generating function
Аннотация: In the Eden model, we investigate how the tree growth parameter depends on the space dimension d for face-centered hypercubic lattices. We find the first three terms of the 1/d-expansion for this parameter directly from the generating function without calculating the number of trees because the growth parameter is the reciprocal coordinate of the singular point of the tree generating function. The same growth parameter was calculated by computer experiment where the ratios between the numbers of trees without intersections and trees without restrictions in the dimensions 3, 4, 6, 8, and 10 were estimated by the Monte Carlo method on face-centered cubic lattices. The results of the two methods agree well. Comparing with the previously performed computer experiment for simple hypercubic lattices, we observe that the values of the singular exponents for the tree generating functions are close for two different types of lattices.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zobov V. E.
Заглавие : Singular points of time-dependent correlation functions of spin systems on large-dimensional lattices at high temperatures
Место публикации : Theor. Math. Phys.: PLENUM PUBL CORP, 2000. - Vol. 123, Is. 1. - P511-523. - ISSN 0040-5779, DOI 10.1007/BF02551058
Примечания : Cited References: 21
Предметные рубрики: BRANCHED POLYMERS
HEISENBERG MAGNET
EXPANSION
MODELS
Аннотация: Time-dependent autocorrelation functions are investigated for the Heisenberg model with spins 1/2 on d-dimensional simple cubic lattices of large dimensions d at infinite temperature. The autocorrelation function on the imaginary time axis is interpreted as the generating function of bond trees constructed with double bonds. These trees provide the leading terms with respect to lid for the time-expansion coefficients of the autocorrelation function. The correction terms from branch intersections to the generating function in the Bethe approximation are derived for these trees. A procedure is suggested for finding the correction to the coordinate of the singular point of the generating function (i.e., to the reciprocal of the branch growth-rate parameter) from the above correction terms without calculating the number of trees. The leading correction terms of order 1/sigma(2) (where sigma = 2d - 1) are found for the coordinates of the singular points of the autocorrelation function in question and for the generating function of the trees constructed with single bonds in the Eden model.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zobov V. E., Popov M. A.
Заглавие : A Monte Carlo study of the dependence of the growth parameter for trees on the lattice dimension in the Eden model
Место публикации : Theor. Math. Phys. - 2001. - Vol. 126, Is. 2. - P.270-279. - ISSN 0040-5779, DOI 10.1023/A:1005260114182
Примечания : Cited References: 17
Предметные рубрики: DIFFUSION-LIMITED AGGREGATION
BRANCHED POLYMERS
HIGH-TEMPERATURES
EXPANSION
TIME
Аннотация: We use the Monte Carlo method to compute the number of trees with n edges in the Eden model on d-dimensional simple cubic lattices for d = 2, 3, 4, 6, 8, 10. We compare these numbers with the exact data derived by the enumeration method up to n = 12 on the square lattice and up to n = 10 on the cubic lattice. We find that for d greater than or equal to 3, the computed values of the growth parameter for trees agree with the values that we derived earlier by the expansion in inverse powers of 2d - 1.
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Hoffman A. E. J., Wieme J., Senkovska I., Krylov A. S., Rogge S. M. J., Kaskel S., Speybroeck V. V.
Заглавие : Tuning terahertz vibrations to control flexibility in soft porous crystals
Коллективы : European conference on metal organic frameworks and porous polymers
Место публикации : 4th European conference on metal organic frameworks and porous polymers: Programme and book of abstracts. - 2021. - Ст.P-74 (S3P15). - ISBN 978-83-951195-7-6
Примечания : Cited References: 7
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Fedorov A. S., Krasnov, Pavel O., Visotin M. A., Tomilin F. N., Polyutov, Sergey P.
Заглавие : Thermoelectric and Plasmonic Properties of Metal Nanoparticles Linked by Conductive Molecular Bridges
Коллективы : Russian Science FoundationRussian Science Foundation (RSF) [16-13-00060]; Ministry of Science and High Education of the Russian Federation; FSRZ-2020-0008 (plasmonic properties)
Место публикации : Phys. Status Solidi B. - 2020. - Vol. 257, Is. 12. - Ст.2000249. - ISSN 0370-1972, DOI 10.1002/pssb.202000249. - ISSN 1521-3951(eISSN)
Примечания : Cited References: 53. - This study was supported by the Russian Science Foundation, project no. 16-13-00060 (thermoelectric properties), and by the Ministry of Science and High Education of the Russian Federation, project no. FSRZ-2020-0008 (plasmonic properties)
Предметные рубрики: POLYMERS
ARRAYS
RANGE
Аннотация: Thermoelectric and plasmonic properties of systems comprising small golden nanoparticles (NPs) linked by narrow conductive polymer bridges are studied using the original hybrid quantum-classical model. The bridges are considered here to be either conjugated polyacetylene, polypyrrole, or polythiophene chain molecules terminated by thiol groups. The parameters required for the model are obtained using density functional theory and density functional tight-binding simulations. Charge-transfer plasmons in the considered dumbbell structures are found to possess frequency in the infrared region for all considered molecular linkers. The appearance of plasmon vibrations and the existence of charge flow through the conductive molecule, with manifestation of quantum properties, are confirmed using frequency-dependent polarizability calculations implemented in the coupled perturbed Kohn-Sham method. To study the thermoelectric properties of the 1D periodical systems, a universal equation for the Seebeck coefficient is derived. The phonon part of the thermal conductivity for the periodical -NP-S-C8H8- system is calculated by the classical molecular dynamics. The thermoelectric figure of meritZTis calculated by considering the electrical quantum conductivity of the systems in the ballistic regime. It is shown that forAu309nanoparticles connected by polyacetylene, polypyrrole, or polythiophene chains atT = 300 K, the ZTvalue is {0.08;0.45;0.40}, respectively.
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova T. G., Zhila N. O., Shishatskaya E. I., Mironov P. V., Vasil'ev A. D., Sukovatyi A. G., Sinskey A. J.
Заглавие : The physicochemical properties of polyhydroxyalkanoates with different chemical structures
Место публикации : Polym. Sci. Ser. A: MAIK Nauka-Interperiodica / Springer, 2013. - Vol. 55, Is. 7. - P.427-437. - 11. - ISSN 0965-545X, DOI 10.1134/S0965545X13070080
Примечания : Cited References: 41
Предметные рубрики: MICROBIAL SYNTHESIS
RALSTONIA-EUTROPHA
COMAMONAS-ACIDOVORANS
AEROMONAS-HYDROPHILA
POLY(3-HYDROXYBUTYRATE-CO-4-HYDROXYBUTYRATE)
BIOSYNTHESIS
COPOLYMERS
POLY(3-HYDROXYBUTYRATE-CO-3-HYDROXYHEXANOATE)
POLYMERS
Аннотация: A set of polyhydroxyalkanoates are synthesized, and a comparative study of their physicochemical properties is performed. The molecular masses and polydispersities of polyhydroxyalkanoates are found to be independent of their chemical structures. It is shown that the temperature characteristics and degrees of crystallinity of polyhydroxyalkanoates are affected by the chemical compositions of the monomers and their quantitative contents in the polymers. The incorporation of 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate units into the chain of poly(3-hydroxybutyrate) decreases its melting point and thermal degradation temperature relative to these parameters of a homogeneous poly(3-hydroxybutyrate) sample (175 +/- 5A degrees C and 275 +/- 5A degrees C, respectively). The higher the content of the second monomer units in the poly(3-hydroxybutirate) chain, the greater the changes. The degrees of crystallinity of polyhydroxyalkanoate copolymers are generally lower than that of poly(3-hydroxybutyrate) (75 +/- 5%). The effect on the ratio of the amorphous and crystalline phases of the copolymer samples becomes more pronounced in the series 3-hydroxy-valerate-3-hydroxyhexanoate-4-hydroxybutyrate. The prepared samples exhibit different properties ranging from rigid thermoplastic materials to engineering elastomers.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Aplesnin S. S., Ryabinkina L. I., Romanova O. B., Har'kov A. M., Gorev M. V., Balaev A. D., Eremin E. V., Bovina A. F.
Заглавие : The magnetoelastic effect in CoxMn1-xS solid solutions
Коллективы :
Разночтения заглавия :авие SCOPUS: The magnetoelastic effect in Cox Mn1 - x S solid solutions
Место публикации : Solid State Commun.: PERGAMON-ELSEVIER SCIENCE LTD, 2010. - Vol. 150, Is. 13-14. - P564-567. - ISSN 0038-1098, DOI 10.1016/j.ssc.2010.01.009
Примечания : Cited References: 13. - This work was supported by the Russian Foundation for Basic Research projects no. 08-02-00364-a, no. 08-02-90031, no. F08037, F08-229, and no. 09-02-00554-a.
Предметные рубрики: YVO3 SINGLE-CRYSTAL
SPIN-STATE
TRANSITION
TRANSPORT
PHYSICS
LACOO3
Ключевые слова (''Своб.индексиров.''): semiconductors--x-ray scattering--galvanomagnetic effects--thermal expansion--semiconductors--x-ray scattering--galvanomagnetic effects--thermal expansion--semiconductors--x-ray scattering--coefficient of thermal expansion--magnetoelastic effects--orbital ordering--temperature hysteresis--temperature range--zero magnetic fields--crystallization--electric resistance--magnetic field effects--magnetoresistance--manganese--manganese compounds--neon--organic polymers--scattering--semiconductor quantum dots--solid solutions--solidification--thermal stress--x ray scattering--thermal expansion
Аннотация: The magnetization of cation-substituted CoxMn(1-x)S sulfides upon cooling in zero magnetic field and in a field in the temperature range 4-300 K has been measured and the resistance versus magnetic field (up to 10 kOe) dependences have been obtained. Magnetoresistance and temperature hysteresis of magnetization versus prehistory are found at the magnetic field H 0.1 T and at T 240 K. The interrelation between the magnetic and elastic subsystems of the CoxMn1-xS solid solutions has been established. A jump in the coefficient of thermal expansion is observed at the Neel temperature. The features of the physical properties are explained by orbital ordering. (C) 2010 Elsevier Ltd. All rights reserved.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Slabko V.V., Volova T.G., Shishatskaya E.I., Kuzubov A.A., Krasnov P.O.
Заглавие : Surface modification of bioresorbable polymer scaffolds by laser treatment
Место публикации : Biophysics. - 2010. - Vol. 55, Is. 2. - С. 234-238. - ISSN 00063509 (ISSN), DOI 10.1134/S0006350910020120
Ключевые слова (''Своб.индексиров.''): hydrophilicity--laser irradiation--microbial biocompatible and biodegradable polymers--polyhydroxybuturate--surface properties
Аннотация: The effect of laser irradiation on the properties of the surface of films prepared from a bioresorbable polymer poly(hydroxybuturate) has been studied. To determine the spectral region of the polymer optimal for the effective action of radiation on electron molecular bonds, theoretical investigations have been performed, which have shown that, for modifying the surface of PHB scaffolds, it is expedient to use a vacuum laser at a wavelength of 160 nm. Using laser irradiation at a power from 3 to 30 W, a series of films with modified surface, from roughnesses to perforations, have been obtained. The microstructure and properties of the film surface depending on the mode of irradiation have been examined, and conditions have been found under which the contact marginal angles of film wetting with water can be decreased to 50° (compared with 76-80° in starting products). Thus, conditions of laser treatment of PHB scaffolds have been theoretically substantiated and experimentally realized that provide a beneficial effect on the properties of the surface without destroying the structure of the material. © 2010 Pleiades Publishing, Ltd.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Loiko V. A., Maschke U., Zyryanov V. Y., Konkolovich A. V., Misckevich A. A.
Заглавие : Small-Angle Light Scattering from Polymer-Dispersed Liquid-Crystal Films
Разночтения заглавия :авие SCOPUS: Small-angle light scattering from polymer-dispersed liquid-crystal films
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2008. - Vol. 107, Is. 4. - P692-698. - ISSN 1063-7761, DOI 10.1134/S1063776108100178
Примечания : Cited References: 20
Предметные рубрики: NEMATIC DROPLETS
Ключевые слова (''Своб.индексиров.''): abs resins--angular distribution--drop formation--drops--light--light scattering--phase transitions--plastic films--polymer films--polymers--polynomial approximation--powders--angle light scatterings--anomalous diffractions--crystal films--cylindrical symmetries--droplet sizes--induced phase transitions--optical wavelengths--pdlc films--scattered lights--scattering approximations--single layers--liquid crystal polymers
Аннотация: A method is developed for modeling and computing the angular distribution of light scattered forward from a single-layer polymer-dispersed liquid-crystal (PDLC) film. The method is based on effective-medium approximation, anomalous diffraction approximation, and far-field single-scattering approximation. The angular distribution of forward-scattered light is analyzed for PDLC films with droplet size larger than the optical wavelength. The method can be used to study field- and temperature-induced phase transitions in LC droplets with cylindrical symmetry by measuring polarized scattered light intensity.
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15.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Krylov A. S., Senkovska I., Kaskel S., Slysareva E. A., Krylova S. N., Yushina I. D., Vtyurin A. N.
Заглавие : Raman spectroscopy study of the switchable phases of metal-organic frameworks DUT-8
Коллективы : European conference on metal organic frameworks and porous polymers
Место публикации : 4th European conference on metal organic frameworks and porous polymers: Programme and book of abstracts. - 2021. - Ст.P-84 (S4P06). - ISBN 978-83-951195-7-6
Примечания : Cited References: 3. - Study was funded by RFBR and DFG, project number 21-52-120018
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zhila N. O., Sapozhnikova K. Yu., Kiselev E. G., Vasiliev A. D., Nemtsev I. V., Shishatskaya E. I., Volova T. G.
Заглавие : Properties of degradable polyhydroxyalkanoates (PHAs) synthesized by a new strain, Cupriavidus necator IBP/SFU-1, from various carbon sources
Место публикации : Polymers. - 2021. - Vol. 13, Is. 18. - Ст.3142. - ISSN 20734360 (ISSN), DOI 10.3390/polym13183142
Примечания : Cited References: 78. - This work was financially supported by Project “Agropreparations of the new generation: a strategy of construction and realization” (Agreement No 075-15-2021-626) in accordance with Resolution No 220 of the Government of the Russian Federation of 9 April 2010, “On measures designed to attract leading scientists to the Russian institutions of higher learning” (strain isolation, polymer synthesis and investigation), and by the State Assignment of the Ministry of Science and Higher Education of the Russian Federation No. FSRZ-2020-0006 (study of film properties)
Аннотация: The bacterial strain isolated from soil was identified as Cupriavidus necator IBP/SFU-1 and investigated as a PHA producer. The strain was found to be able to grow and synthesize PHAs under autotrophic conditions and showed a broad organotrophic potential towards different carbon sources: sugars, glycerol, fatty acids, and plant oils. The highest cell concentrations (7–8 g/L) and PHA contents were produced from oleic acid (78%), fructose, glucose, and palm oil (over 80%). The type of the carbon source influenced the PHA chemical composition and properties: when grown on oleic acid, the strain synthesized the P(3HB-co-3HV) copolymer; on plant oils, the P(3HB-co-3HV-co-3HHx) terpolymer, and on the other substrates, the P(3HB) homopolymer. The type of the carbon source influenced molecular-weight properties of PHAs: P(3HB) synthesized under autotrophic growth conditions, from CO2, had the highest number-average (290 ± 15 kDa) and weight-average (850 ± 25 kDa) molecular weights and the lowest polydispersity (2.9 ± 0.2); polymers synthesized from organic carbon sources showed increased polydispersity and reduced molecular weight. The carbon source was not found to affect the degree of crystallinity and thermal properties of the PHAs. The type of the carbon source determined not only PHA composition and molecular weight but also surface microstructure and porosity of the polymer films. The new strain can be recommended as a promising P(3HB) producer from palm oil, oleic acid, and sugars (fructose and glucose) and as a producer of P(3HB-co-3HV) from oleic acid and P(3HB-co-3HV-co-3HHx) from palm oil.
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volova, Tatiana G., Kiselev, Evgeniy G., Demidenko, Alexey V., Zhila, Natalia O., Nemtsev I. V., Lukyanenko A. V.
Заглавие : Production and properties of microbial polyhydroxyalkanoates synthesized from hydrolysates of Jerusalem artichoke tubers and vegetative biomass
Коллективы : Project "Agropreparations of the new generation: a strategy of construction and realization" [075-15-2021-626]; State Assignment of the Ministry of Science and Higher Education of the Russian Federation [FSRZ-2020-0006]
Место публикации : Polymers. - 2022. - Vol. 14, Is. 1. - Ст.132. - ISSN 2073-4360(eISSN), DOI 10.3390/polym14010132
Примечания : Cited References: 93. - This study was financially supported by Project "Agropreparations of the new generation: a strategy of construction and realization" (Agreement No. 075-15-2021-626) in accordance with Resolution No. 220 of the Government of the Russian Federation of 9 April 2010, "On measures designed to attract leading scientists to the Russian institutions of higher learning" (polymer synthesis, properties), and by the State Assignment of the Ministry of Science and Higher Education of the Russian Federation No. FSRZ-2020-0006 (films production, surface properties)
Предметные рубрики: GLUCOSE-UTILIZING STRAIN
RALSTONIA-EUTROPHA
ASPERGILLUS-NIGER
ACID
Аннотация: One of the major challenges in PHA biotechnology is optimization of biotechnological processes of the entire synthesis, mainly by using new inexpensive carbon substrates. A promising substrate for PHA synthesis may be the sugars extracted from the Jerusalem artichoke. In the present study, hydrolysates of Jerusalem artichoke (JA) tubers and vegetative biomass were produced and used as carbon substrate for PHA synthesis. The hydrolysis procedure (the combination of aqueous extraction and acid hydrolysis, process temperature and duration) influenced the content of reducing substances (RS), monosaccharide contents, and the fructose/glucose ratio. All types of hydrolysates tested as substrates for cultivation of three strains—C. necator B-10646 and R. eutropha B 5786 and B 8562—were suitable for PHA synthesis, producing different biomass concentrations and polymer contents. The most productive process, conducted in 12-L fermenters, was achieved on hydrolysates of JA tubers (X = 66.9 g/L, 82% PHA) and vegetative biomass (55.1 g/L and 62% PHA) produced by aqueous extraction of sugars at 80 °C followed by acid hydrolysis at 60 °C, using the most productive strain, C. necator B-10646. The effects of JA hydrolysates on physicochemical properties of PHAs were studied for the first time. P(3HB) specimens synthesized from the JA hydrolysates, regardless of the source (tubers or vegetative biomass), hydrolysis conditions, and PHA producing strain employed, exhibited the 100–120 °C difference between the Tmelt and Tdegr, prevailing of the crystalline phase over the amorphous one (Cx between 69 and 75%), and variations in weight average molecular weight (409–480) kDa. Supplementation of the culture medium of C. necator B-10646 grown on JA hydrolysates with potassium valerate and ε-caprolactone resulted in the synthesis of P(3HB-co-3HV) and P(3HB-co-4HB) copolymers that had decreased degrees of crystallinity and molecular weights, which influenced the porosity and surface roughness of polymer films prepared from them. The study shows that JA hydrolysates used as carbon source enabled productive synthesis of PHAs, comparable to synthesis from pure sugars. The next step is to scale up PHA synthesis from JA hydrolysates and conduct the feasibility study. The present study contributes to the solution of the critical problem of PHA biotechnology—finding widely available and inexpensive substrates.
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gavrilyuk A. P., Karpov S. V.
Заглавие : Processes in resonant domains of metal nanoparticle aggregates and optical nonlinearity of aggregates in pulsed laser fields
Место публикации : Appl. Phys. B-Lasers Opt. - NEW YORK: SPRINGER, 2009. - Vol. 97, Is. 1. - С. 163-173. - SEP. - ISSN 0946-2171, DOI 10.1007/s00340-009-3592-y
Примечания : Cited Reference Count: 43. - Гранты: Authors are thankful to Prof. V. A. Markel ( University of Pennsylvania) for computation of multipole polarizability of silver nanoparticle bispheres, for the attention to this paper, fruitful discussions and great support. This research was supported by grants: 27.1 of the Presidium of RAS, 9.1 DPS RAS, 5 SB RAS, 3818.2008.3 and 6612.2006.3 of the President of RF ( SS RAS), DSP 2.1.1.1814, 05- 03- 32642 RFBR.Финансирующая организация: [27.1 of the Presidium of RAS]; [9.1 DPS RAS]; [5 SB RAS]; [3818.2008.3]; [6612.2006.3]
Предметные рубрики: SMALL-PARTICLE COMPOSITES
FRACTAL CLUSTERS
SELECTIVE PHOTOMODIFICATION
ABSORPTION-COEFFICIENTS
REFRACTIVE-INDEXES
SILVER
ENHANCEMENT
RESPONSES
GOLD
Ключевые слова (''Своб.индексиров.''): metal nanoparticles--nanosecond pulsed laser--nonlinear refractive index--optical nonlinearity--physical effects--pulsed-laser field--resonant domain--silver nanoparticles--simple physical models--aggregates--laser excitation--nanoparticles--nonlinear optics--organic polymers--pulsed laser applications--refractive index--silver
Аннотация: Optical nonlinearities in aggregates of nanoparticles formed in silver hydrosols (SHs) are studied under pico- and nanosecond pulsed laser excitation. The dependence of the nonlinear refractive index n (2) on the degree of hydrosol aggregation is studied experimentally at the wavelength lambda=1.064 mu m. It is found that n (2) changes sign when the degree of hydrosol aggregation is increased. Various physical effects occurring in resonant domains of the aggregates are analyzed using a simple physical model of two bound silver nanoparticles. The theory takes into account thermal, elastic, electrostatic, and light-induced effects. Experimental results are discussed in the context of this theory.
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19.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Churilov G. N., Dudnik A. I., Osipova I. V., Vnukova N. G., Nikolaev N. S., Volochaev M. N., Tomashevich Y. V.
Заглавие : Preparation of polymers based on fullerenes and nanoparticles of titanium carbide and their properties
Коллективы : "Advanced carbon nanostructures", International conference, Физико-технический институт им. А.Ф. Иоффе РАН, Национальный исследовательский центр "Курчатовский институт", Санкт-Петербургский государственный технологический институт (технический университет)
Место публикации : 13th Int. Conf. "Adv. Carbon Nanostructures": Book of abstracts. - 2017. - Poster session 1: Fullerenes and Nanodiamond Particles. - Ст.P1-14. - P.83. - ISBN 978-5-93634-037-6
Примечания : Библиогр.: 1
Аннотация: When carbon condensate (CC) is synthesized by spraying graphite rods containing doping powders in arc discharge plasma, usually, in addition to fullerenes, nanoparticles, metal nanoparticles with a carbon shell or nanoparticles of metal carbide are formed [1]. The description of a procedure for the preparation of polymers based on fullerenes and nanodispersed titanium carbide particles and the results of investigation of these polymers will be given in this paper. Titanium and titanium oxide are used as doping powders. The solutions extracted with carbon disulfide are filtered through paper filters. According to X-ray diffraction analysis and transmission electron microscope, the carbon disulphide extract from CC synthesized with the inputting of metallic titanium, does not contain nanoparticles of this metal or its carbide and is characterized by the presence of fullerite clusters (extract 1). While the extract from the CC synthesized with the titanium oxide inputting contains TiC nanoparticles with size of 7–10 nm, while fullerenes are also contained, but in the amorphous state (extract 2) of Fig.1. HPLC analysis of the fullerenes toluene solution, obtained by redissolution of extract 1, allowed to isolate the fullerenes with the usual composition and with the usual ratio between components (C60 – 74.4 %, C70 – 18.9 % and higher fullerenes – 6.7 %). The redissolution of extract 2 in toluene, did not allow to obtain fullerenes solution. Thus, the presence of nanodispersive particles of TiC in the fullerenes solution, upon their drying, leads to polymers formation.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gardymova A. P., Krakhalev M. N., Rudyak V. Yu., Barbashov V. A., Zyryanov V. Ya.
Заглавие : Polymer-dispersed cholesteric liquid crystal under homeotropic anchoring: Electrically induced structures with λ1/2-disclination
Место публикации : Polymers. - 2022. - Vol. 14, Is. 7. - Ст.1454. - ISSN 20734360 (ISSN), DOI 10.3390/polym14071454
Примечания : Cited References: 44. - This research was funded by Russian Science Foundation, Grant No. 20-72-10038
Аннотация: Orientational structures of polymer-dispersed cholesteric liquid crystal under homeotropic anchoring and their transformations under the action of an electric field are studied. The switching of cholesteric droplets between different topological states are experimentally and theoretically demonstrated. Structures with λ+1/2-disclination are found and considered. These structures are formed during the transformation of a twisted toroidal configuration induced by a decrease in the electric field when a relative chiral parameter N06.3. The transformation of the initial structure with a bipolar distribution of the helix axis into a twisted toroidal configuration and then into a structure with λ+1/2-disclination is investigated in detail. The behavior of these structures under the influence of an external electric field, as well as the appearance of structures with λ−1/2-disclination, are studied. Obtained results are promising for the development of optical materials with programmable properties.
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