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Wyszukujesz frazę "Czechowski, N." wg kryterium: Wszystkie pola


Wyświetlanie 1-9 z 9
Tytuł:
Geochemical characterization and palaeoenvironmental implications of lipids in Neogene lignites and lignitic shales in NW Poland
Autorzy:
Czechowski, Franciszek
Polowczyk, Marzena
Simoneit, Bernt R. T.
Grelowski, Cezary
Hojniak, Marek
Powiązania:
https://bibliotekanauki.pl/articles/27311291.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
Lignites
biomarkers
n-alkanes and isoprenoids
diterpenoids
triterpenoids
polycyclic aromatic hydrocarbons
Opis:
The lipophilic biomarker distributions in lipids of Neogene lignites and lignitic shales in western Pomerania and the midlands of Poland are presented. Twenty-six lignite samples and seven lignitic shales were obtained from twenty-four boreholes. Their extracts were separated, using thin-layer chromatography, and the saturate and aromatic fractions were analyzed by gas chromatography-mass spectrometry. The molecular compositions of n-alkanes, isoprenoids, n-alkylcyclohexanes, n-alkylbenzenes, tri- and tetracyclic diterpenoids, pentacyclic triterpenoids, as well as polycyclic aromatic hydrocarbons (PAHs) with up to five rings, were determined. The samples displayed n-alkane distributions in the range of C14–C35 and high odd-over-even carbon number predominances (CPI(25–33) from 2.9 to 7.9). Diterpanes consisted primarily of phyllocladane, abietane, isopimarane, labdane, and kaurane structures, although their abundances varied among the samples. Hopanes exhibited the biological and geochemical characteristics of low-maturity organic matter. Minor oleanane triterpenoids from angiosperms were also found. A few samples displayed evidence of biodegradation on the basis of the advanced isomerization of αβ-hopanes and the presence of short-chained n-alkanes, n-alkylcyclohexanes, and n-alkylbenzenes. A more mature stage of the above biomarkers also may have resulted in part from the oxidation of organic matter. The lignite source materials were derived from conifer and angiosperm flora as well as microbial remnants. The contribution from marine phytoplankton was excluded on the basis of the lack of C27 steroids. PAHs were predominantly perylene or phenanthrene, with minor other analogues. Thus, the data support progressive lacustrine/lagoonal sedimentation in the palaeoenvironmental mires.
Źródło:
Annales Societatis Geologorum Poloniae; 2023, 93, 4; 447--466
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fluorescence Mapping of PCP Light-Harvesting Complexes Coupled to Silver Nanowires
Autorzy:
Krajnik, B.
Piatkowski, D.
Olejnik, M.
Czechowski, N.
Hofmann, E.
Heiss, W.
Mackowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1419489.pdf
Data publikacji:
2012-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.64.kv
42.62.Fi
81.07.Pr
87.64.M-
Opis:
In this work we demonstrate confocal fluorescence imaging of hybrid nanostructures composed of silver nanowires and peridinin-chlorophyll-protein light-harvesting complexes. The length of silver nanowires, which reaches 10 μm, allows for determination of the nanowire position and consequently direct correlation with the fluorescence image. In this way we probe the influence of plasmon induced electromagnetic field on the fluorescence of light-harvesting complexes. When the nanowires are spaced from the light-harvesting complexes by a 10 nm thick dielectric layer, we observe a fluorescence enhancement, which depends upon the laser excitation wavelength. The measured enhancement values are 2.5 and 1.9 for 405 nm and 485 nm, respectively. Larger enhancement for the 405 nm excitation is attributed to direct creation of plasmon excitations in the silver nanowires.
Źródło:
Acta Physica Polonica A; 2012, 122, 2; 259-262
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fluorescence Microscopy of Corrole-Single Silver Nanowire Hybrid Nanostructures
Autorzy:
Czechowski, N.
Olejnik, M.
Nowak-Król, A.
Piątkowski, D.
Heiss, W.
Gryko, D.
Mackowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1419537.pdf
Data publikacji:
2012-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.50.-j
78.67.Uh
73.20.Mf
81.07.Pr
81.07.-b
Opis:
We report on confocal microscopy imaging of hybrid nanostructures composed of silver nanowires and corroles. Both nanomaterials were separated by a 30 nm thick $SiO_2$ spacer in order to inhibit fluorescence quenching. The results show that for such a hybrid nanostructure the average enhancement of the fluorescence intensity reached 2.5. Importantly, the coupling to plasmon excitations in metallic nanowires leaves no effect on the fluorescence spectrum of the organic molecules.
Źródło:
Acta Physica Polonica A; 2012, 122, 2; 333-336
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectral Dependence of Fluorescence Enhancement in LH2-Au Nanoparticle Hybrid Nanostructures
Autorzy:
Bujak, L.
Brotosudarmo, T.
Czechowski, N.
Olejnik, M.
Ciszak, K.
Litvin, R.
Cogdell, R.
Heiss, W.
Mackowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1419487.pdf
Data publikacji:
2012-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.80.Dj
78.47.D-
78.67.Qa
82.35.Np
Opis:
We report on the influence of plasmon resonance in spherical gold nanoparticles on the optical properties of light-harvesting complex LH2 from the purple bacteria Rhodopseudomonas palustris. Systematic studies as a function of the excitation energy and the separation distance indicate that metal enhanced fluorescence shows strong dependence upon both of these parameters. We observe substantial increase of the fluorescence from LH2 complex in a hybrid nanostructure with 12 nm silica spacer. On the other hand, the enhancement measured with laser tuned into the plasmon resonance is almost threefold compared to the off-resonance configuration. The enhancement of fluorescence intensity originates in both cases from the increase of carotenoid absorption in the LH2 complex.
Źródło:
Acta Physica Polonica A; 2012, 122, 2; 252-254
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dielectric Relaxation in Hydrogen Bonded Urea-Based Supramolecular Polymer N,N-di(2,2-dipentylheptyl)urea
Autorzy:
Jadżyn, J.
Bouteiller, L.
Déjardin, J.-L.
Czechowski, G.
Powiązania:
https://bibliotekanauki.pl/articles/2047092.pdf
Data publikacji:
2006-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.82.Pv
77.22.Gm
81.16.Fg
82.30.Rs
Opis:
Results of the dielectric relaxation studies, performed for supramolecular polymer formed by N,N'-di(2,2-dipentylheptyl)urea dissolved in carbon tetrachloride, are presented. The measurements were done for N,N'-di(2,2-dipentylheptyl)urea concentration up to about 7% (in mole fraction) in the frequency region from 100 kHz to 100 MHz and at the temperatures from 5ºC to 50ºC. The analysis of the experimental data were performed with the Havriliak-Negami equation. In the studied range of N,N'-di(2,2-dipentylheptyl)urea concentration and temperature, the obtained values of exponentsα andβ of the Havriliak-Negami equation are equal to 0.9±0.1 and 0.7±0.1, respectively, showing an anomaly in the dielectric relaxation behavior close to the Davidson-Cole type. Two examples of the modeling of dielectric properties of the supramolecular polymer solutions were presented.
Źródło:
Acta Physica Polonica A; 2006, 110, 4; 495-504
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dielectric, Viscous, and Elastic Properties of Mesogenic 4-n-Hexyloxy-4-Cyanobiphenyl
Autorzy:
Czechowski, G.
Jadżyn, J.
Powiązania:
https://bibliotekanauki.pl/articles/2027368.pdf
Data publikacji:
2001-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.70.Md
77.84.Nh
77.22.Gm
66.20.+d
Opis:
The paper presents the results of measurements of the static and dynamic electric permittivity, the shear viscosity, and the splay and bend elastic constants for 4-n-hexyloxy-4' -cyanobiphenyl (C$\text{}_{6}$H$\text{}_{13}$O-Ph-Ph-C≡N). On the basis of the static values of the nematic principal permittivities, ε$\text{}_{ǁ}$ (T) and $\varepsilon_{\bot}(T)$, the angle between the dipole moment vector and the long axis of 4-n-hexyloxy-4'-cyanobiphenyl molecule, the apparent dipole moment and the nematic order parameter were determined. From the temperature dependences of the dielectric relaxation time (corresponding to the molecular rotation around the short axis) and the shear viscosity, the strength of the nematic potential and the effective length of 4-n-hexyloxy-4'-cyanobiphenyl molecule (in isotropic phase) were estimated. The K$\text{}_{11}$ and K$\text{}_{33}$ elastic constants were determined from the voltage dependence of the capacitance of the planar nematic cell with the method proposed by Gruler et al. and Uchida et al.
Źródło:
Acta Physica Polonica A; 2001, 99, 5; 579-591
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
[Cztery] 4-n-Alkilobicyklo[2,2,2]octano-1-karboksylany 2-chloro-4-heptylofenylu : synteza i właściwości fizyczne nowych nematyków o ujemnej anizotropii dielektrycznej
Autorzy:
Dąbrowski, Roman.
Dziaduszek, Jerzy.
Stolarz, Zofia.
Jadżyn, Jan.
Czechowski, Grzegorz.
Kasprzyk, Monika.
Powiązania:
Biuletyn Wojskowej Akademii Technicznej 2000, nr 8, s. 43-61
Data publikacji:
2000
Tematy:
Kryształy ciekłe
Metody badawcze
Opis:
Rys., tab.; Bibliogr.; Abstr., Rez., streszcz.
Dostawca treści:
Bibliografia CBW
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
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
    Wyświetlanie 1-9 z 9

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