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Wyszukujesz frazę "64.70.Md" wg kryterium: Temat


Tytuł:
Dynamics of the Molecules in Solid Phases of Few Chosen Schiff Bases Compounds
Autorzy:
Bąk, A.
Massalska-Arodź, M.
Powiązania:
https://bibliotekanauki.pl/articles/2037298.pdf
Data publikacji:
2004-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Md
77.22.Gm
Opis:
The dielectric relaxation processes observed in solid phases of MBBA, OH-MBBA, and EBBA belonging to the homologous series of the Schiff bases are discussed. The data are compared with the results completed by the present authors for EBPA compound. The uniform interpretation of the temperature changes of relaxation for all mentioned compounds is proposed.
Źródło:
Acta Physica Polonica A; 2004, 105, 5; 467-474
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Guest Effect on Nematic-Isotropic Phase Transition Temperature of Liquid Crystal 6CHBT
Autorzy:
Bauman, D.
Solczyński, J.
Chrzumnicka, E.
Powiązania:
https://bibliotekanauki.pl/articles/1968468.pdf
Data publikacji:
1997-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.30.Gd
64.70.Md
Opis:
The polarized absorption spectra of seven dichroic azo dyes dissolved in the nematogenic liquid crystal host 6CHBT have been recorded as a function of temperature. On the basis of these spectra, the guest order parameter has been determined. Moreover, the influence of the dye addition on the behaviour of the guest-host mixture in the vicinity of the nematic- isotropic phase transition has been examined. The experimental results have been compared in some details with the calculations done on the basis of the mean field theory for binary mixtures.
Źródło:
Acta Physica Polonica A; 1997, 92, 6; 1151-1161
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Guest-Host Interactions in Nematic p-Cyano-p-Alkylphenylcyclohexanes
Autorzy:
Bauman, D.
Moryson, H.
Jadżyn, J.
Powiązania:
https://bibliotekanauki.pl/articles/1930624.pdf
Data publikacji:
1994-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.30.Gd
64.70.Md
Opis:
Studies of the temperature dependence of the guest order parameter for binary mixtures of the dichroic azo dye in the homologous series of the p-cyano-p'-alkylphenylcyclohexane were performed. Odd-even effect for the order parameter value was observed. A correlation between the shift in the nematic-isotropic transition temperature after dye addition and the orientation of the guest molecules in the nematic host was discussed.
Źródło:
Acta Physica Polonica A; 1994, 85, 3; 553-562
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular Dynamics of n-p-(Ethoxybenzylidene) P-Propylaniline in Nematic and Solid Phases as Studied by Dielectric Relaxation Spectroscopy
Autorzy:
Bąk, A.
Massalska-Arodź, M.
Urban, S.
Powiązania:
https://bibliotekanauki.pl/articles/2012951.pdf
Data publikacji:
2000-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Md
77.22.Gm
Opis:
The complex dielectric permittivity ε*(ν,T) = ε'(ν,T) - iε''(ν,T) of n-p-(ethoxybenzylidene) p'-propylaniline has been measured in the frequency range from 1 Hz to 13 MHz and temperature range from 360 K to 180 K on heating and on cooling the sample. Dielectric relaxations have been found in nematic and solid phases. A detailed analysis of the observed processes has been performed and the parameters describing molecular dynamics have been evaluated. The comparison of results with those obtained for the other Schiff bases is discussed.
Źródło:
Acta Physica Polonica A; 2000, 97, 2; 323-330
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Magnetic Fredericksz Transition in Ferronematics
Autorzy:
Kopčanský, P.
Koneracká, M.
Jadżyn, J.
Czechowski, G.
Żywucki, B.
Powiązania:
https://bibliotekanauki.pl/articles/1964799.pdf
Data publikacji:
1997-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Md
61.30.Gd
Opis:
The magnetic Fredericksz transition in ferronematics (thermotropic nematic liquid crystals 7CB and MBBA combined with fine magnetic particles of a size 10 nm) as a function of concentration of magnetic particles was studied by using simple dielectric measurements. The increase of the threshold magnetic field is observed in 7CB based ferronematic while the decrease of threshold field in MBBA based ferronematic is observed when the concentration of magnetic particles is increased. Experimental results are discussed in the framework of Brochard, de Gennes and Burylov, Raikher theories.
Źródło:
Acta Physica Polonica A; 1997, 92, 2; 437-440
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamics of 4-(2-hexyloxy-ethoxy) 4-cyanobiphenyl Molecules on Approaching a Glass Transition as Studied by Dielectric Spectroscopy
Autorzy:
Massalska-Arodź, M.
Witko, W.
Gorbachev, V.
Hartmann, L.
Kremer, F.
Powiązania:
https://bibliotekanauki.pl/articles/2037035.pdf
Data publikacji:
2003-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Md
64.70.Pf
77.22.Gm
Opis:
The complex dielectric permittivity of 4-(2-hexyloxy-ethyloxy) 4'-cyano-biphenyl measured in the frequency range from 0.03 Hz to 10$\text{}^{9}$ Hz is presented. Monotropic sequence of thermodynamic phases was found with two stable phases (isotropic and crystal) and three metastable states (supercooled isotropic phase, its glass and a smectic phase observed only on heating the sample first cooled rapidly to the liquid nitrogen temperature). In isotropic and supercooled isotropic phases the temperature dependence of the dielectric relaxation time was described by the same Vogel-Fulcher-Tammann formula while in a smectic phase it was of the Arrhenius type. In the transition from a supercooled isotropic phase to a smectic phase the relaxation rate of molecular motions around the short axes increases by two decades. Comparison of the relaxation behaviour and polymorphism of 4-(2-hexyloxy-ethyloxy) 4'-cyano-biphenyl of linear molecules with two chiral cyanobiphenyls is discussed.
Źródło:
Acta Physica Polonica A; 2003, 104, 6; 527-536
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Fluid-Like and Critical Behavior of the Isotropic-Nematic Transition Appearing in Linear and Non-linear Dielectric Studies
Autorzy:
Drozd-Rzoska, A.
Rzoska, S. J.
Zioło, J.
Powiązania:
https://bibliotekanauki.pl/articles/2014495.pdf
Data publikacji:
2000-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Md
64.30.+t
77.22.Ch
Opis:
A short review of literature and the authors' experimental results for the pretransitional behavior in the isotropic phase of nematogens is given. The paper also presents new results of non-linear dielectric effect and dielectric permittivity measurements in the broad temperature range. Results obtained show significant advantages of non-linear dielectric effect and dielectric permittivity for studying pretransitional properties in liquid crystalline materials. The paper contains a comprehensive comparison of the experiment with predictions of the mean-field model and the fluid-like description. The presented analysis strongly supports the image of the isotropic phase as a complex liquid resulting from vicinity of the fluid-like, "nematic-isotropic", critical point.
Źródło:
Acta Physica Polonica A; 2000, 98, 5; 637-643
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Singular Elastic Properties of Mixtures with the Re-entrant Nematic Phase
Autorzy:
Czechowski, G.
Jadżyn, J.
Powiązania:
https://bibliotekanauki.pl/articles/2038376.pdf
Data publikacji:
2004-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Md
62.20.Dc
61.30.-v
Opis:
The paper presents temperature behavior of the splay and bend elastic constants measured for n-hexyloxycyanobiphenyl and n-octyloxycyanobiphenyl mixtures - a system exhibiting the re-entrant nematic phase. It was shown that singularities in the elastic properties of the system concern not only the nematic phase (the well-known pre-smectic effects) but first of all - the smectic A phase, in which the splay and bend deformations, normally not allowed for the layered structures, can be induced.
Źródło:
Acta Physica Polonica A; 2004, 106, 4; 475-485
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Order Parameter of Dichroic Azo-Dyes in Liquid Crystalline Side-Chain Polysiloxanes
Autorzy:
Chrzumnicka, E.
Bauman, D.
Jadżyn, J.
Powiązania:
https://bibliotekanauki.pl/articles/2035645.pdf
Data publikacji:
2002-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.41.+e
61.30.Gd
64.70.Md
Opis:
Polarized light absorption spectra of seven dichroic azo-dyes dissolved in mesogenic side-chain polysiloxanes were recorded as a function of temperature. On the basis of the spectra the optical order parameter of the dyes was determined. The influence of the dye on the phase transition temperatures of polysiloxanes was examined. The results obtained for polysiloxanes were compared with the data for low molecular weight liquid crystal.
Źródło:
Acta Physica Polonica A; 2002, 102, 6; 767-780
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Dielectric Relaxation in Solutions of the Polar Mesogenic Molecules in the Isotropic Phase
Autorzy:
Kędziora, P.
Powiązania:
https://bibliotekanauki.pl/articles/2036876.pdf
Data publikacji:
2003-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Md
72.20.Ht
68.35.Rh
Opis:
The nonlinear spectra of 4,4'-n-hexylcyanobiphenyl (C$\text{}_{6}$H$\text{}_{13}$-Ph-Ph-CN) in benzene solutions were recorded in the frequency range of 300~kHz-100~MHz in the presence of the strong static electric field E$\text{}_{0}$=1.1×10$\text{}^{7}$ V/m, at 25˚C. The dynamic pretransitional phenomena revealed for polar C$\text{}_{6}$H$\text{}_{13}$-Ph-Ph-CN were interpreted in the frame of the Landau-de Gennes theory. The identical concentration-dependent behavior of nonlinear relaxation time in the vicinity of the transition from the isotropic to the nematic phase for polar and nonpolar compounds was discussed.
Źródło:
Acta Physica Polonica A; 2003, 104, 1; 45-53
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dielectric Properties of Liquid Crystalline Isothiocyanato-tolane Derivatives with Fluorine Atom at Various Lateral Positions
Autorzy:
Czub, J.
Urban, S.
Dąbrowski, R.
Gestblom, B.
Powiązania:
https://bibliotekanauki.pl/articles/2043376.pdf
Data publikacji:
2005-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Md
77.22.Gm
77.84.Nh
Opis:
Dielectric studies were performed for several isothiocyanato-tolane compounds having the F atom attached to the benzene rings at different lateral positions and the alkoxy or alkyl chain at the p-position. They form the nematic phase in broad temperature intervals. The static as well as dynamic properties of the compounds in the nematic and isotropic phases were studied. Tensor permittivity components: ε$\text{}_{ǁ}$, ε$\text{}_{⊥}$, Δε, as functions of temperature were measured. The complex dielectric permittivity, ε$\text{}^{*}$(f)=ε'(f)-iε''(f), was measured in the frequency range of 1 kHz - 3 GHz from which the relaxation times τ$\text{}_{ǁ}$ and τ$\text{}_{⊥}$ were calculated. The order parameter S(T) was determined from the dielectric data. It was found that the close vicinity of the F atom and the alkoxy group results in blocking of the internal rotation of the wing around the O-phenyl bond.
Źródło:
Acta Physica Polonica A; 2005, 107, 6; 947-958
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scaling in 2-d Distribution of Topological Defects in a Liquid Crystal
Autorzy:
Massalska-Arodź, M.
Powiązania:
https://bibliotekanauki.pl/articles/1968968.pdf
Data publikacji:
1998-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.30.Jf
61.43.Hv
64.70.Md
Opis:
Distribution of the topological point defects observed microscopically by Nagaya, Hotta, Orihira and Ishibashi in Schlieren texture of N-(4-n-methoxy benzylidene) 4'-n'-butylaniline has been analyzed. The same fractal dimensionality D$\text{}_{f}$=1.4 has been estimated for several sets of defects obtained in subsequent stages of evolution of the nematic sample after the transition from the isotropic liquid phase.
Źródło:
Acta Physica Polonica A; 1998, 94, 1; 41-47
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radiation Stability of the BSA Modified Biocompatible Magnetic Fluid
Autorzy:
Tomašovičová, N.
Haysak, I.
Kováč, J.
Kubovčíková, M.
Závišová, V.
Timko, M.
Okunev, A.
Zorkovská, A.
Kopčanský, P.
Powiązania:
https://bibliotekanauki.pl/articles/1368667.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Mm
61.30.Gd
64.70.Md
Opis:
The aim of the presented work was to investigate the stability of biocompatible magnetic fluid, i.e. water-based magnetic fluid containing magnetite nanoparticles stabilized by surfactant sodium oleate and modified by bovine serum albumin (BSA) after electron irradiation. Samples with the same concentration of $Fe_{3}O_{4}$ but different mass ratio BSA/$Fe_{3}O_{4}$ (w/w=0.25, 1.0 and 2.5) were studied. The electron irradiation caused about 10% reduction of the saturation magnetization in the samples with w/w BSA/$Fe_{3}O_{4}$ ratio of 0.25 and less than 5% in the samples with w/w BSA/$Fe_{3}O_{4}$ ratio of 1 and 2.5.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 262-263
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular Dynamics of 4-(trans-4-n-Heptylcyclohexyl)- Isothiocyanatobenzene Studied with Dielectric Relaxation Spectroscopy
Autorzy:
Bauman, D.
Czechowski, G.
Jadżyn, J.
Legrand, C.
Douali, R.
Powiązania:
https://bibliotekanauki.pl/articles/2014055.pdf
Data publikacji:
2000-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Md
77.84.Nh
77.22.Gm
Opis:
Dielectric relaxation study was carried out for the nematic and isotropic phases of 4-(trans-4'-n- heptylcyclohexyl)isothiocyanatobenzene in the frequency range from 100 kHz to 1 GHz. In the nematic phase two relaxation processes were recorded for the electric permittivity component measured parallel to the molecular orientation (director n) and three relaxation processes - for the perpendicular permittivity component. The strength of the nematic potential and the nematic order parameter were estimated.
Źródło:
Acta Physica Polonica A; 2000, 98, 1-2; 71-81
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dielectric Relaxation of 4-Cyanophenyl 4-n-Decyloxybenzoate in the Isotropic, Nematic, and Smectic A Phases
Autorzy:
Ginovska, M.
Czechowski, G.
Andonovski, A.
Jadżyn, J.
Powiązania:
https://bibliotekanauki.pl/articles/2014555.pdf
Data publikacji:
2000-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Md
77.84.Nh
77.22.Gm
Opis:
The paper presents the results of the dielectric relaxation study performed for the isotropic, nematic, and smectic A phases of 4-cyanophenyl 4'-n-decyloxybenzoate (C$\text{}_{10}$H$\text{}_{21}$O-Ph-COO-Ph-C≡ N, CP10DB) in the frequency range from 100 kHz to 100 MHz. In the nematic and smectic A phases the permittivity was measured with the probing electric field E parallel to the macroscopic molecular orientation (the director n). The recorded dielectric spectra correspond to the rotation of CP10DB molecules around the short axis and can be quite well described in the framework of the Debye model. It was found that the values of the activation energy for the molecular reorientations in the isotropic and smectic A phases of CP10DB are quite close to each other, whereas in the nematic phase the energy is remarkably higher.
Źródło:
Acta Physica Polonica A; 2000, 98, 6; 715-720
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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