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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Berman G. P., Kolovsky A. R.
Заглавие : A quantum nonlinear resonance with account of relaxation processes
Место публикации : Physica A. - 1987. - Vol. 141, Is. 2-3. - P.602-612. - ISSN 0378-4371, DOI 10.1016/0378-4371(87)90186-5
Примечания : Cited References: 12
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2.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Mironov V. L., Savin I. V., Muzalevskiy K. V.
Заглавие : A temperature-dependent multi-relaxation spectroscopic dielectric model for thawed and frozen organic soil at 0.05-15 Ghz
Коллективы : Geoscience and Remote Sensing Symposium
Место публикации : Geoscience and Remote Sensing Symposium (IGARSS), 2015 IEEE International. - 2015. - P.2031-2034. - DOI 10.1109/IGARSS.2015.7326198
Аннотация: The dielectric model for an arctic organic-rich soil collected on the Yamal peninsula (50% of organic matter) both thawed and frozen has been developed. The model is based on the soil dielectric measurements carried out in the ranges of gravimetric moisture 0.03 to 0.55 g/g, dry soil density 0.72 to 0.87 g/cm3, and temperature 25 to −30°C (cooling run), in the frequency range 0.05–15 GHz. To fit the results of measurements of the soil complex dielectric constant as a function of soil moisture and wave frequency, the refractive mixing dielectric model in conjunction with the Debye multi-relaxation equations were applied. As a result, the spectroscopic parameters of dielectric relaxations and electrical specific conductivities for the bound, transient bound, and unbound soil water components were derived, being further complimented with the thermodynamics parameters. Having these parameters, the complex dielectric constant of soil can be predicted as a function of 1) density of dry soil, 2) gravimetric moisture, 3) wave frequency, and 4) temperature1.
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3.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Mironov V. L., Savin I. V.
Заглавие : A temperature-dependent multi-relaxation spectroscopic dielectric model for thawed and frozen organic soil at 0.05–15 GHz
Место публикации : Phys. Chem. Earth: PERGAMON-ELSEVIER SCIENCE LTD, 2015. - Vol. 83–84: Emerging science and applications with microwave remote sensing data. - P.57-64. - ISSN 1474-7065, DOI 10.1016/j.pce.2015.02.011
Примечания : Cited References: 14. - The study was supported by the Russian Science Foundation (project 14-17-00656).
Предметные рубрики: ARCTIC SOIL
BOREAL
Ключевые слова (''Своб.индексиров.''): organic soil--moisture--temperature--dielectric model--thawed and frozen soil--smos
Аннотация: A dielectric model for thawed and frozen Arctic organic-rich soil (50% organic matter) has been developed. The model is based on soil dielectric measurements that were collected over ranges of gravimetric moisture from 0.03 to 0.55 g/g, dry soil density from 0.72 to 0.87 g/cm3, and temperature from 25 to −30 °C (cooling run) in the frequency range of 0.05–15 GHz. The refractive mixing dielectric model was applied with the Debye multi-relaxation equations to fit the measurements of the soil’s complex dielectric constant as a function of soil moisture and wave frequency. The spectroscopic parameters of the dielectric relaxations for the bound, transient bound, and unbound soil water components were derived and were complimented by the thermodynamic parameters to obtain a complete set of parameters for the proposed temperature-dependent multi-relaxation spectroscopic dielectric model for moist soils. To calculate the complex dielectric constant of the soil, the following input variables must be assigned: (1) density of dry soil, (2) gravimetric moisture, (3) wave frequency, and (4) temperature. The error of the dielectric model was evaluated and yielded RMSEε′ values of 0.348 and 0.188 for the soil dielectric constant and the loss factor, respectively. These values are on the order of the dielectric measurement error itself. The proposed dielectric model can be applied in active and passive microwave remote sensing techniques to develop algorithms for retrieving the soil moisture and the freeze/thaw state of organic-rich topsoil in the Arctic regions.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Lundin A. A., Zobov V. E.
Заглавие : Asymptotic similarity of time correlation functions and shape of the 13C and 29Si NMR spectra in diamond and silicon
Коллективы : Institute of Chemical Physics of the Russian Academy of Science [0082-2018-0005, TSITIS AAAA-A18-118020690203]
Место публикации : J. Exp. Theor. Phys. - 2018. - Vol. 127, Is. 2. - P.305-315. - ISSN 1063-7761, DOI 10.1134/S1063776118080216. - ISSN 1090-6509(eISSN)
Примечания : Cited References: 47. - We thank V.A. Atsarkin, V.V. Demidov, F.S. Dzheparov, and E. B. Feldman for the discussion of our results. This work was supported by a subsidy allocated by the Institute of Chemical Physics of the Russian Academy of Science for the State assignment, theme 0082-2018-0005, code TSITIS AAAA-A18-118020690203.
Предметные рубрики: SPIN SYSTEMS
LINE-SHAPES
RELAXATION
SOLIDS
PARAMAGNETS
RESONANCE
Аннотация: Based on the proposed theory, we have investigated the shape of the NMR absorption spectra for 13C and 29Si nuclei in diamond and silicon crystals attributable to the internuclear dipole–dipole interaction. In accordance with the available experimental data, we have considered both crystals with a 100% content of magnetoactive isotopes and crystals with a comparatively low dilution by nonmagnetic nuclei. The time correlation functions (the first of which is the Fourier transform of the NMR spectrum) arising in an infinite chain of coupled differential equations are shown to be mutually similar with a slight time delay. The proposed theory allows the spectrum to be calculated analytically. The results obtained agree satisfactorily with the experimental ones. It is noted that the mutual similarity of the time correlation functions is probably a corollary of the development of dynamical chaos in the system.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : ZOBOV V. E.
Заглавие : AUTOCORRELATION FUNCTIONS OF THE ANISOTROPIC HEISENBERG PARAMAGNET IN THE APPROXIMATION OF A SELF-CONSISTENT FLUCTUATING FIELD
Место публикации : Theor. Math. Phys.: PLENUM PUBL CORP, 1990. - Vol. 84, Is. 1. - P751-757. - ISSN 0040-5779, DOI 10.1007/BF01017200
Примечания : Cited References: 10
Предметные рубрики: RELAXATION
Аннотация: The method proposed earlier for investigating the dynamics of the isotropic Heisenberg paramagnet at high temperatures is generalized to the anisotropic case. A system of nonlinear integrodifferential equations relating the three autocorrelation functions of the x, y, and z components of an individual spin is obtained. A solution of the system is sought in the form of series in powers of the time and is investigated on the plane of the complex time variable. The coefficients of the series up to the tenth order for the xy model and the model with truncated dipole interaction are calculated, and the parameters of the singular points nearest the origin are determined from them.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Berzhanskii V. N., Ivanov V. I.
Заглавие : Ccritical relaxation in CDCR2SE4 ferromagnet
Место публикации : Fiz. Tverd. Tela. - 1980. - Vol. 22, Is. 6. - P.1871-1873. - ISSN 0367-3294
Примечания : Cited References: 7
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7.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Nasluzov V. A., Rivanenkov V. V., Gordienko A. B., Neyman K. M., Birkenheuer U., Rosch N.
Заглавие : Cluster embedding in an elastic polarizable environment: Density functional study of Pd atoms adsorbed at oxygen vacancies of MgO(001)
Место публикации : J. Chem. Phys.: AMER INST PHYSICS, 2001. - Vol. 115, Is. 17. - P8157-8171. - ISSN 0021-9606, DOI 10.1063/1.1407001
Примечания : Cited References: 88
Предметные рубрики: TRANSITION-METAL ATOMS
AB-INITIO
OXIDE SURFACES
ELECTRONIC-PROPERTIES
ENERGY CALCULATIONS
MOLECULAR-DYNAMICS
MOTT-LITTLETON
MADELUNG FIELD
IONIC-CRYSTAL
MGO
Ключевые слова (''Своб.индексиров.''): atoms--binding energy--computer simulation--electron energy levels--electronic structure--magnesia--oxygen--palladium--polarization--probability density function--quantum theory--relaxation processes--charged defects--cluster embedding--elastic polarizable environment--electron affinity--oxygen vacancies--adsorption
Аннотация: Adsorption complexes of palladium atoms on F-s, F-s(+), F-s(2+), and O2- centers of MgO(001) surface have been investigated with a gradient-corrected (Becke-Perdew) density functional method applied to embedded cluster models. This study presents the first application of a self-consistent hybrid quantum mechanical/molecular mechanical embedding approach where the defect-induced distortions are treated variationally and the environment is allowed to react on perturbations of a reference configuration describing the regular surface. The cluster models are embedded in an elastic polarizable environment which is described at the atomistic level using a shell model treatment of ionic polarizabilities. The frontier region that separates the quantum mechanical cluster and the classical environment is represented by pseudopotential centers without basis functions. Accounting in this way for the relaxation of the electronic structure of the adsorption complex results in energy corrections of 1.9 and 5.3 eV for electron affinities of the charged defects F-s(+) and F-s(2+), respectively, as compared to models with a bulk-terminated geometry. The relaxation increases the stability of the adsorption complex Pd/F-s by 0.4 eV and decreases the stability of the complex Pd/F-s(2+) by 1.0 eV, but it only weakly affects the binding energy of Pd/F-s(+). The calculations provide no indication that the metal species is oxidized, not even for the most electron deficient complex Pd/F-s(2+). The binding energy of the complex Pd/O2- is calculated at -1.4 eV, that of the complex Pd/F-s(2+) at -1.3 eV. The complexes Pd/F-s and Pd/F-s(+) exhibit notably higher binding energies, -2.5 and -4.0 eV, respectively; in these complexes, a covalent polar adsorption bond is formed, accompanied by donation of electronic density to the Pd 5s orbital. (C) 2001 American Institute of Physics.
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8.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Berzhanskii V. N., Ivanov V. I.
Заглавие : Critical relaxation of uniform precession of magnetization in cubic ferrimagnets
Место публикации : Phys. Status Solidi B. - 1989. - Vol. 151, Is. 1. - P.259-267. - ISSN 0370-1972, DOI 10.1002/pssb.2221510130
Примечания : Cited References: 22
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zobov V. E., Lundin A. A.
Заглавие : Decay of multispin multiquantum coherent states in the NMR of a solid
Место публикации : J. Exp. Theor. Phys.: MAIK NAUKA/INTERPERIODICA/SPRINGER, 2011. - Vol. 112, Is. 3. - P451-459. - ISSN 1063-7761, DOI 10.1134/S1063776111020129
Примечания : Cited References: 24
Предметные рубрики: SYSTEMS
SPECTRA
Ключевые слова (''Своб.индексиров.''): adiabatic approximations--andersons--coherent state--dynamic phenomena--experimental data--local fields--model-based--radiospectroscopy--relaxation functions--spin precession--theoretical result--two-component--coherent light
Аннотация: A model based on the Anderson adiabatic approximation, which is widely used for describing various aspects of dynamic phenomena in conventional radiospectroscopy, is proposed for describing the decay of multispin multiquantum coherent states in a solid. The coherent state relaxation function is represented by the product of two functions corresponding to spin precession in a two-component local field with a correlated and an uncorrelated component. Theoretical results of this study explain the experimental data reported in a number of publications and are in good agreement with these data.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Zobov V. E., Lundin A. A.
Заглавие : Dependence of the relaxation rate of coherent states on the number of correlated spins and the order of coherence
Колич.характеристики :6 с
Место публикации : JETP Lett. - 2023. - Vol. 117, Is. 12. - P.932-937. - ISSN 00213640 (ISSN), DOI 10.1134/S0021364023601525. - ISSN 10906487 (eISSN)
Примечания : Cited References: 29. - This work was supported by the Ministry of Science and Higher Education of the Russian Federation (state assignment no. 122040500060-4)
Аннотация: The relaxation of the components of the multiple-quantum NMR spectrum of a solid under the effect of the dipole–dipole interactions during the evolution period is considered. It is taken into account that clusters of dynamically correlated spins of different sizes are formed in the preparatory period, and their degradation depends on their size and coherence order. To calculate the size distribution function of clusters and their degradation function, a physical model including relaxation processes is developed. Using this model, an analytical result for a multiple-quantum spectrum is obtained. Agreement is obtained between the theoretical and experimental dependences of the coherence degradation rates in adamantane scaled by the square root of the average cluster size. The parameters of the above functions are found from the comparison of these dependences.
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11.

Вид документа : Статья из сборника (выпуск продолж. издания)
Шифр издания :
Автор(ы) : Mironov V. L., Molostov I. P., Scherbinin V. V.
Заглавие : Dielectric model of a mineral arctic soil thawed and frozen at 0.05-15 GHz
Коллективы : International Siberian Conference on Control and Communications
Место публикации : Int. Sib. Conf. on Control and Communicat. (SIBCON 2015): Proceedings: IEEE-Institute Electrical and Electronics Engineers, 2015. - P.1-7. - , DOI 10.1109/SIBCON.2015.7147146
Ключевые слова (''Своб.индексиров.''): arctic regions--dielectric model--dielectric relaxation--remote sensing--soil--temperature dependence--dielectric relaxation--moisture--remote sensing--soil moisture--soils--temperature--temperature distribution--thawing--thermodynamics--active and passive remote sensing--arctic regions--complex dielectric constant--dielectric modeling--soil dielectric constant--spectroscopic parameters--temperature dependence--thermodynamics parameters--soil surveys
Аннотация: The dielectric model for an arctic soil both thawed and frozen has been developed. The model is based on the soil dielectric measurements carried out in the ranges of gravimetric moisture from 0.01 to 0.43 g/g, dry soil density from 1.25 to 1.83 g/cm3, and temperature from 25 to -30°C (cooling run), in the frequency range 0.05-15 GHz. To fit the results of measurements of the soil complex dielectric constant as a function of soil moisture and wave frequency, the refractive mixing dielectric model in conjunction with the Debye multi-relaxation equations were applied. As a result, the spectroscopic parameters of dielectric relaxations for the bound, transient bound, and unbound soil water components were derived, being further complimented with the thermodynamics parameters to ensure a complete set of parameters of the temperature dependent multi-relaxation spectroscopic dielectric model for moist soils proposed. To calculate complex dielectric constant of soil, the following input variables have to be assigned: 1) density of dry soil, 2) gravimetric moisture, 3) wave frequency, and 4) temperature. The error of the dielectric model was evaluated in terms of RMSE, yielding the values RMSE of 0.53 and 0.43 for the soil dielectric constant and loss factor, respectively. These values appeared to be in the order of the dielectric measurement error itself. The dielectric model suggested can be applied in the active and passive remote sensing techniques in microwave to develop algorithms for retrieving soil moisture and freeze/thaw state of the topsoil in the Arctic regions. © 2015 IEEE.
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12.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Mironov V. L., Molostov I. P., Scherbinin V. V.
Заглавие : Dielectric model of a mineral arctic soil thawed and frozen at 0.05-15 GHz
Место публикации : International Siberian Conference on Control and Communications (SIBCON) (MAY 21-23, 2015, Omsk, RUSSIA): IEEE, 2015. - С. 2684-2687. - ISBN 978-1-4799-7103-9
Примечания : Cited References:11
Ключевые слова (''Своб.индексиров.''): dielectric model--temperature dependence--dielectric relaxation--soil--arctic regions--remote sensing
Аннотация: The dielectric model for an arctic soil both thawed and frozen has been developed. The model is based on the soil dielectric measurements carried out in the ranges of gravimetric moisture from 0.01 to 0.43 g/g, dry soil density from 1.25 to 1.83 g/cm(3), and temperature from 25 to -30 degrees C (cooling run), in the frequency range 0.05-15 GHz. To fit the results of measurements of the soil complex dielectric constant as a function of soil moisture and wave frequency, the refractive mixing dielectric model in conjunction with the Debye multi-relaxation equations were applied. As a result, the spectroscopic parameters of dielectric relaxations for the bound, transient bound, and unbound soil water components were derived, being further complimented with the thermodynamics parameters to ensure a complete set of parameters of the temperature dependent multi-relaxation spectroscopic dielectric model for moist soils proposed. To calculate complex dielectric constant of soil, the following input variables have to be assigned: 1) density of dry soil, 2) gravimetric moisture, 3) wave frequency, and 4) temperature. The error of the dielectric model was evaluated in terms of RMSE, yielding the values RMSE of 0.53 and 0.43 for the soil dielectric constant and loss factor, respectively. These values appeared to be in the order of the dielectric measurement error itself. The dielectric model suggested can be applied in the active and passive remote sensing techniques in microwave to develop algorithms for retrieving soil moisture and freeze/thaw state of the topsoil in the Arctic regions.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bobrov P. P., Mironov V. L., Repin A. V.
Заглавие : Dielectric permittivity spectra of oil-water-saturated sandy-clayey rocks of different mineralogical compositions and relaxation properties of water in these rocks
Коллективы : RFBR [12-05-00502a, 14-05-00151a]
Место публикации : Russ. Geol. Geophys.: Elsevier Science, 2015. - Vol. 56, Is. 7. - P.1065-1073. - ISSN 1068-7971, DOI 10.1016/j.rgg.2015.06.007
Примечания : Cited References: 21. - This work was supported by RFBR (grant nos. 12-05-00502a and 14-05-00151a).
Предметные рубрики: MOIST SOILS
FREQUENCY
MODEL
TEMPERATURE
SALINITY
RANGE
GHZ
Ключевые слова (''Своб.индексиров.''): conductivity--dielectric permittivity--multifrequency dielectric relaxation--oil-bearing deposits--sandy-clayey rocks
Аннотация: Experimental measurements of the dielectric permittivity and equivalent conductivity of sandy-clayey samples (a mixture of river sand with bentonite or kaolin) saturated with salt-solution-diesel-fuel emulsions were performed in the frequency range from 10 kHz to 1 GHz at temperatures of 25-65 °C. It is shown that when the content of the salt solution in the saturating fluid does not exceed 10%, the dielectric permittivity in the frequency range from 1 MHz to 1 GHz depends little on the mineral composition of the sample and on the concentration of the saturating solution. When the portion of water is 33.3% or higher, increasing the concentration of the salt solution leads to an increase in the equivalent conductivity and the real part of the complex dielectric permittivity. Using the refractive model of the complex dielectric permittivity, we have estimated the dielectric properties of bound water, which depend on temperature and the type of clay (bentonite or kaolin) in the sand-clay mixture but are independent of the water saturation and the amount of clay in the sample.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Volkov N. V., Eremin E. V., Sablina K. A., Sapronova N. V.
Заглавие : Dielectric properties of a mixed-valence Pb3Mn7O15 manganese oxide
Коллективы :
Разночтения заглавия :авие SCOPUS: Dielectric properties of a mixed-valence Pb3Mn7O 15 manganese oxide
Место публикации : J. Phys.: Condens. Matter: IOP PUBLISHING LTD, 2010. - Vol. 22, Is. 37. - Ст.375901. - ISSN 0953-8984, DOI 10.1088/0953-8984/22/37/375901
Примечания : Cited References: 14. - This study was supported by the Russian Foundation for Basic Research 'Siberia', project No. 09-02-98003, and the Siberian Branch of the Russian Academy of Sciences, integration project No. 101.
Ключевые слова (''Своб.индексиров.''): cation--lead--manganese derivative--oxide--article--chemical model--chemistry--crystallization--electric conductivity--electronics--methodology--temperature--cations--crystallization--electric conductivity--electronics--lead--manganese compounds--models, chemical--oxides--temperature--ac electric field--analysis of resistivity--carrier hopping--charge ordering--complex dielectric constant--crystal site--debye models--dielectric constants--dielectric spectra--frequency windows--lattice sites--low frequency--manganese ions--mixed valence--mixed valence state--relaxation behaviors--temperature range--electric fields--manganese--manganese oxide--permittivity--single crystals--crystal symmetry
Аннотация: We investigated the low-frequency dielectric properties of a Pb3Mn7O15 single crystal with manganese ions in the mixed-valence state (Mn3+/Mn4+). Dielectric relaxation was found in the frequency window from 20 to 100 kHz in the temperature range 110-180 K. The dielectric spectra of the crystal were analyzed using a Debye model. Estimations made within the model and analysis of resistivity data suggest that the relaxation behavior of the dielectric constant is related to polaronic charge carrier hopping. Around 250 K, charge ordering occurs in the crystal when the Mn3+ and Mn4+ ions are arranged in a specific order among the crystal sites. With a decrease in temperature, an ac electric field can induce a charge hop between the equivalent lattice sites available, related to crystal symmetry. This hopping is equivalent to the reorientation of an electric dipole that yields Debye-type behavior of the complex dielectric constant. The observed anisotropy in the behavior of the dielectric properties and resistivity can be attributed to a pronounced two-dimensional character of the crystal structure.
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15.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Gao Q., Hu Q., Jin L., Gorev M. V., Chezganov D. S., Vlasov E. O., Zeng H., Zhao L., Cui Y., Xu Z., Wei X.
Заглавие : Dielectric relaxation and phase transition behavior of (1–x)Pb(Zn1/3Nb2/3)O3-xBaTiO3 binary solid solutions
Место публикации : Ceram. Int. - 2018. - Vol. 44, Is. 15. - P.18491-18498. - ISSN 02728842 (ISSN), DOI 10.1016/j.ceramint.2018.07.069
Примечания : Cited References: 53. - This work was supported by the National Basic Research Program of China (Grant No. 2015CB654602 ), the International Science & Technology Cooperation Program of China (Grant No. 2015DFA51100 ), the NSFC projects (Grant Nos. 51761145024 and 51772239 ), Shaanxi province project 2017 ktpt-21, the Joint fund of the Ministry of Education (Grant No. 6141A02033210 ) and the 111 Project under Grant No. B14040 . The SEM work was done at International Center for Dielectric Research (ICDR), Xi’an Jiaotong University, Xi’an, China.
Ключевые слова (''Своб.индексиров.''): dielectric relaxation--phase transition--“u”-shaped variation--polarization mismatch
Аннотация: Dielectric relaxation and phase transition behaviors in (1–x)Pb(Zn1/3Nb2/3)O3-xBaTiO3 (PZN-BT) binary solid solutions have been systematically studied in this paper. All the compositions display a pure pseudo-cubic perovskite structure. As the BT contents increase from 10 mol% to 70 mol%, the phase transition peak becomes broader and broader, accompanying with decreases of ɛm (the maximum dielectric permittivity) and Tm (the temperature corresponds to the ɛm). Nevertheless, an abnormal increase of ɛm and Tm occurs when the BT contents exceeds 70 mol%, forming a “U” shaped curve of the compositional dependence of ɛm and Tm. Moreover, it is indicated from the new glass model fitting results that the characteristic parameter p, which represents the degree of relaxation, also shows a similar “U” shaped variation curve. Similarly, as shown in polarization-electric field loops, both remnant polarizations (Pr) and coercive fields (Ec) display the “U” shaped curve as the BT content changes from 10 mol% to 80 mol%. Finally, according to the similar variation of these key parameters mentioned above, a polarization mismatched model, which describes the destruction and reestablishment of the long range order arrangement in solid solutions composed of two kinds of ferroelectrics, is proposed to illustrate the underlying mechanism. In this PZN-BT system or other similar ABO3-type perovskite relaxors, the competition between the A-O and B-O coupling plays an important role to form the “U” shaped evolution of these key parameters.
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Belyaev B. A., Drokin N. A., Shabanov V. F.
Заглавие : Dielectric relaxation of trans-4-propyl-(4-cyanophenyl)-cyclohexane liquid crystals
Разночтения заглавия :авие SCOPUS: Dielectric Relaxation of trans-4-Propyl-(4-Cyanophenyl)-Cyclohexane Liquid Crystals
Место публикации : Phys. Solid State. - 2004. - Vol. 46, Is. 3. - P.579-583. - ISSN 1063-7834, DOI 10.1134/1.1687882
Примечания : Cited References: 11
Аннотация: The frequency dependences of the permittivity of a trans-4-propyl-(4-cyanophenyl)-cyclohexane (3PCH) liquid crystal in the nematic phase are measured in the frequency range 1-2000 MHz for different orientations of the director of liquid-crystal molecules with respect to the polarization of an ac electric field. The temperature dependences of the dielectric and optical characteristics are compared in the range of the transition from the nematic phase to the isotropic liquid phase. The dielectric spectra are approximated numerically, and the times of dipole relaxation upon rotation of the molecules about the short and long axes are determined. It is demonstrated that intramolecular motions make a significant contribution to the relaxation. The activation enthalpies are calculated. (C) 2004 MAIK "Nauka / Interperiodica".
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17.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Belyaev B. A., Drokin N. A., Shabanov V. F.
Заглавие : Distribution function of relaxation times for a 4-n-pentyl-4 '-cyanobiphenyl liquid crystal
Разночтения заглавия :авие SCOPUS: Distribution function of relaxation times for a 4-n-pentyl-4′- cyanobiphenyl liquid crystal
Место публикации : Phys. Solid State: AMER INST PHYSICS, 2005. - Vol. 47, Is. 9. - P1791-1796. - ISSN 1063-7834, DOI 10.1134/1.2045369
Примечания : Cited References: 15
Предметные рубрики: DIELECTRIC-RELAXATION
SPECTRA
INVERSION
Аннотация: The distribution function of relaxation times is reconstructed from the dielectric loss spectrum measured over a wide range of frequencies for a 4-n-pentyl-4'-cyanobiphenyl (5CB) liquid crystal. It is demonstrated that the distribution function for the isotropic and nematic phases is asymmetric in shape. Comparison shows that the reconstructed distribution function is in qualitative agreement with similar functions that are analytically derived from the Cole-Davidson and Havriliak-Negami empirical equations. The specific features observed in the behavior of the distribution function with a variation in the angle between the direction of polarization of a microwave electric field and the director of the liquid-crystal molecules are analyzed. A complex dependence of the permittivity for the liquid crystal in the range of ultrahigh frequencies is explained in terms of additional relaxation mechanisms associated with different motions of molecular fragments of alkyl chains. (c) 2005 Pleiades Publishing, Inc.
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18.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Balaev D. A., Stolyar S. V., Krasikov A. A., Bayukov O. A., Yaroslavtsev R. N., Velikanov D. A., Iskhakov R. S., Knyazev Yu. V.
Заглавие : Effect of the interparticle interactions on superparamagnetic relaxation
Коллективы : Российская академия наук, Физико-технический институт им. Е.К. Завойского ФИЦ Казанского научного центра РАН, Казанский (Приволжский) федеральный университет, Euro-Asian Symposium "Trends in MAGnetism", "Trends in MAGnetism", Euro-Asian Symposium
Место публикации : VIII Euro-Asian symposium "Trends in magnetism" (EASTMAG-2022): Book of abstracts/ program com. S. G. Ovchinnikov [et al.]. - 2022. - Vol. 1, Sect.: Magnetotransport, magnetooptics and magnetophotonics. - Ст.D.O11. - P.437-438. - ISBN 978-5-94469-051-7
Примечания : Cited References: 3. - This study was supported by the Russian Science Foundation, Project No. 21-72-00025 (https://rscf.ru/project/21-72-00025/)
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Cheng F., Xia, Zhiguo, Molokeev M. S., Jing X.
Заглавие : Effects of composition modulation on the luminescence properties of Eu3+ doped Li1-xAgxLu(MoO4)2 solid-solution phosphors
Место публикации : Dalton Trans.: Royal Society of Chemistry, 2015. - Vol. 44, Is. 41. - P.18078-18089. - ISSN 1477-9226, DOI 10.1039/c5dt02760h
Примечания : Cited References: 42. - The present work was supported by the National Natural Science Foundations of China (Grant No. 51272242, 51572023, 51511130035), Natural Science Foundations of Beijing (2132050), the Program for New Century Excellent Talents in University of Ministry of Education of China (NCET-12-0950), Beijing Nova Program (Z131103000413047), Beijing Youth Excellent Talent Program (YETP0635), the Funds of the State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences (RERU2015022), and the excellent tutor section of the Fundamental Research Funds for the Central Universities of China University of Geosciences, Beijing (2-9-2015-028). This work was also partly supported by the Russian Foundation for Basic Research (Grant No. 15-52-53080 GFEN_a).
Предметные рубрики: RED PHOSPHORS
PHOTOLUMINESCENCE PROPERTIES
ENERGY-TRANSFER
WHITE LEDS
IONS
NA
POLYMORPHISM
TUNGSTATES
RELAXATION
MOLYBDATES
Аннотация: Double molybdate scheelite-type solid-solution phosphors Li1−xAgxLu1−y(MoO4)2:yEu3+ were synthesized by the solid state reaction method, and their crystal structures and luminescence properties were investigated in detail. The composition modulation and structural evolution of this series of samples were studied and the selected AgEu(MoO4)2, AgLu(MoO4)2, LiLu(MoO4)2 and LiEu(MoO4)2 phases were analyzed based on the Rietveld refinement. Depending on the variation of the Li/Ag ratio in Li1−xAgxLu1−y(MoO4)2:yEu3+ phosphors, the difference in the luminescence properties of Li1−xAgxLu1−y(MoO4)2:yEu3+ phosphors was ascribed to two factors, one reason could be assigned to the coupling effect and the nonradiative transition between the energy levels of LixAg1−xLu(MoO4)2 matrices and the activator Eu3+, another could be due to the near ultraviolet energy absorption and transmission efficiency between the charge-transfer (CT) band of O2−–Mo6+ and the 4f → 4f emissive transitions of Eu3+. The ultraviolet-visible diffuse reflection spectra (UV-vis DRS) and Raman spectra analysis were also used to verify the above mechanism.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krakhalev M. N., Gardymova A. P., Rudyak, Vladimir Yu., Barbashov, Vadim A., Zyryanov V. Ya.
Заглавие : Electrically induced transformation of cholesteric droplets under homeotropic boundary conditions
Колич.характеристики :7 с
Место публикации : J. Mol. Liq. - 2023. - Vol. 385. - Ст.122379. - ISSN 01677322 (ISSN), DOI 10.1016/j.molliq.2023.122379. - ISSN 18733166 (eISSN)
Примечания : Cited References: 37. - This research was funded by Russian Science Foundation, Grant No. 20-72-10038. The research was carried out using the equipment of the shared research facilities of HPC computing resources at Lomonosov Moscow State University
Аннотация: Cholesteric droplets under homeotropic boundary conditions demonstrate a rich variety of possible orientational structures. We have implemented electrically controlled switching of such droplets between two classes of stable states: i) structures with cylindrical cholesteric layers and ii) layer-like structures with one or more λ+1/2-disclinations. Structure relaxation after switching off the voltage proceeded via the fast (less than 1 s), the slow (more than 1 s), and the stabilization stages (~10 hours). We investigated intermediate long-lived metastable states occurring in the relaxation process and explained the formation of various structures in cholesteric droplets. The fast and the slow stages of relaxation were found to be sensitive to the voltage reduction regime. We have determined the combinations of droplet size and voltage reduction regimes leading to the two types of structures after relaxation.
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