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Wyszukujesz frazę "Grudziński, W." wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
Spectroscopy of Photosynthetic Pigment-Protein Complex LHCII
Autorzy:
Gruszecki, W.
Zubik, M.
Luchowski, R.
Grudzinski, W.
Gryczynski, Z.
Gryczynski, I.
Powiązania:
https://bibliotekanauki.pl/articles/1490052.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.64.-t
Opis:
Light-harvesting pigment-protein complex of photosystem II is the most abundant membrane protein in the biosphere, comprising more than half chlorophyll molecules. The protein plays a role of photosynthetic antenna, collecting solar radiation and transferring excitations towards the reaction centers, where electric charge separation takes place. Efficient excitation energy capture and transfer requires unique organization of the complex and unique photophysical properties of the accessory pigments: chlorophylls and carotenoids. LHCII is also a place where extremely harmful singlet oxygen may be generated, under strong illumination conditions. Several physical mechanisms have been found in LHCII, operating to protect the photosynthetic apparatus against light-induced damage, including chlorophyll triplet and singlet excitations quenching by carotenoids. In this paper we discuss the results of our recent studies, carried out with the application of several molecular spectroscopy techniques (electronic absorption, fluorescence, resonance Raman and FTIR), designed to investigate molecular mechanisms responsible for regulation of excitation density in LHCII. Among the most interesting findings are the light-induced molecular configuration changes of the LHCII-bound xanthophylls, leading to conformational rearrangements of the protein. These mechanisms are discussed in terms of excessive excitation quenching in the pigment-protein complex subjected to overexcitation. Such an activity seems to represent a vital regulatory process in the photosynthetic apparatus, at the molecular level, protecting plants against photodegradation.
Źródło:
Acta Physica Polonica A; 2012, 121, 2; 397-400
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modification of Optical and Electrical Properties of PET Foils by He⁺, Ne⁺ and Ar⁺ Implantation
Autorzy:
Droździel, A.
Turek, M.
Pyszniak, K.
Prucnal, S.
Luchowski, R.
Grudziński, W.
Klimek-Turek, A.
Partyka, J.
Powiązania:
https://bibliotekanauki.pl/articles/1033733.pdf
Data publikacji:
2017-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.40.Me
78.30.Jw
61.82.Pv
Opis:
Thin (3 μm) polyethylene terephthalate (PET) foils were irradiated with 135 keV He⁺, Ne⁺ and Ar⁺ ions with the fluences up to 5×10¹⁵ cm¯². Changes of chemical structure of the polymer were studied with the Fourier transform infrared and Raman spectroscopy - breaking of numerous chemical bonds, polymer chain cross-linking as well as formation of sp² hybridised carbon clusters and cluster networks were demonstrated. The increase of the implanted sample absorbance with the implantation fluence in the UV-VIS spectra as well as the decrease of optical band-gap energy (2.75 and 2.0 eV for He and Ne, respectively, at 5×10¹⁵ cm¯²) are observed. Decrease of bulk resistance of heavily treated samples by ≈5 orders of magnitude is determined. Measurements of the sheet resistance confirm that the sample becomes conducting also on the reverse (unimplanted) side of the foil. Both of these effects depend on the impinging ion mass - they are the strongest for Ar. The increase of both ac conductance and dielectric constant is observed in the frequency range up to 2 MHz and these changes rise with the impinging ion mass.
Źródło:
Acta Physica Polonica A; 2017, 132, 2; 264-269
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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