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Wyszukujesz frazę "Sikorski, R. T." wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Positron Annihilation Studies of Styrene-N-X-Phenylmaleimides
Autorzy:
Baranowski, A.
Dębowska, M.
Jerie, K.
Rudzińska-Girulska, J.
Pawełka, Z.
Sikorski, R. T.
Powiązania:
https://bibliotekanauki.pl/articles/1933467.pdf
Data publikacji:
1995-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.60.+z
78.70.Βj
81.20.Sh
82.30.Hk
Opis:
Results of angular correlation of annihilation radiation and positron annihilation lifetime measurements are presented for five styrene copolymers: poly(co-styrene-phenylmaleimide) and its three derivatives with chlorine as well as for one with the OH group substituted in the benzene ring. It occurs that the chlorine substituted in three different positions in the benzene ring poly(co-styrene-o (or -m, -p)-chlorophenylmaleimide) inhibits the formation of the positronium to different extent. The greatest effect is observed in case of the chlorine atoms substituted in the benzene ring at ortho-position towards the nitrogen atom. In addition, electric dipole moments were measured for N-X-phenylmaleimide units, to check whether their magnitude influences the positron annihilation parameters. On the basis of the present results no correlation between the positron annihilation parameters and the electric dipole moments of the units was noticed.
Źródło:
Acta Physica Polonica A; 1995, 88, 1; 51-57
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Annihilation in Chloropolystyrenes
Autorzy:
Baranowski, A.
Dębowska, M.
Jerie, K.
Mirkiewicz, G.
Rudzińska-Girulska, J.
Sikorski, R. T.
Powiązania:
https://bibliotekanauki.pl/articles/1928863.pdf
Data publikacji:
1993-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.60.+z
78.70.Bj
81.20.Sh
82.30.Hk
Opis:
Results of angular correlation of annihilation radiation and positron annihilation lifetime measurements are presented for atactic polystyrene and chloropolystyrenes. The inhibition of positronium formation follows the chlorine introduction as the decrease in intensities of the narrow component in angular correlation of annihilation radiation curves and of the longest-lived component in positron annihilation lifetime spectra prove. In general, the chlorine "activity" towards positrons seems to depend on its position in the polymer structure. The annihilation rate distribution as well as the radius and volume distributions of free-volume sites where positronium is assumed to be formed obtained with the use of CONTIN program for the raw sample in the 2nd series are given additionally.
Źródło:
Acta Physica Polonica A; 1993, 83, 3; 239-249
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zimoziół północny Linnaea borealis L. w północnej części Niziny Południowopodlaskiej
The Twinflower (Linnaea borealis L.) in the northern part of the Poludniowopodlaska Lowland
Autorzy:
Ciosek, M.T.
Krechowski, J.
Sikorski, R.
Trębicka, A.
Piórek, K.
Powiązania:
https://bibliotekanauki.pl/articles/1311248.pdf
Data publikacji:
2015
Wydawca:
Instytut Badawczy Leśnictwa
Tematy:
rosliny
gatunki zagrozone
zimoziol polnocny
Linnaea borealis
wystepowanie
fitosocjologia
Nizina Poludniowopodlaska
distribution
phytosociology
Południowopodlaska Lowland
Opis:
Linnaea borealis, the twinflower, is considered a critically endangered species in the Południowopodlaska Lowland. The disappearance of the twinflower is mainly caused by habitat changes resulting from forest management, but also light deficiency due to the increase in canopy cover and growth of the shrub layer (processes of succession). The aim of the paper is to present the actual distribution and phytosociological characteristics of L. borealis in the northern part of the Południowopodlaska Lowland. In this region, only three out of ten known areas of occurrence (Werchliś, Serpelice, Grala-Dąbrowizna) have endured to the present day. The twinflower occurs in pine forest, Peucedano-Pinetum, and mixed forest, Querco roboris-Pinetum, communities. A decrease in the ground cover of twinflower populations was observed in all existing twinflower locations. Although the area covered by the Linnaea borealis population in Werchliś increased tenfold during the last 20 years (from about 200 m2 in 1993 to 1970 m2 in 2013), its cover-abundance according to the Braun-Blanquet scale decreased from 5 to 3. The increase in the area covered by the twinflower population together with the accompanying decrease in cover-abundance is probably not a manifestation of species dynamics but rather a response to disadvantageous environmental changes (growth of canopy cover and shrub layer). Progressive light reduction can initiate the process of fragmentation of a population. A decrease in the cover-abundance of the L. borealis population (from 4 to 2) was also observed in Serpelice. Its area was reduced to half of its original size due to anthropogenic destruction of this location. In the third region, Grala-Dąbrowizna, also the negative effects of competitive species (e.g. Vaccinium myrtillus, V. vitis-idaea) are considered.
Źródło:
Leśne Prace Badawcze; 2015, 76, 2; 113-121
1732-9442
2082-8926
Pojawia się w:
Leśne Prace Badawcze
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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