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Wyszukujesz frazę "Wilamowski, J." wg kryterium: Autor


Tytuł:
Oxidative metabolism, mutagenic and carcinogenic properties of some polycyclic aromatic hydrocarbons
Autorzy:
Łuczyński, M. K.
Góra, M.
Brzuzan, P.
Wilamowski, J.
Kozik, B.
Powiązania:
https://bibliotekanauki.pl/articles/363172.pdf
Data publikacji:
2005
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
metabolizm tlenowy
właściwości mutagenne
właściwości rakotwórcze
wielopierścieniowe węglowodory aromatyczne
oxidative metabolism
mutagenic properties
carcinogenic properties
polycyclic aromatic hydrocarbons
Opis:
This attempt to synthesize the present state of knowledge on the correlation between the structure of chosen PAHs and their mutagenic or carcinogenic activity shows that the dependencies cannot be treated univocally. Extreme complexity of the subject, typical for investigations on the boundary between chemistry and biology, inclines one to search for new ways of synthesis of new compounds, which would be of interest for biologists studying the problem of chemical carcinogenesis. On the other hand, there is a strong need for elaborating a standardized test that would explicitly define the carcinogenic properties of a specific compound. The use of a variety of methods for the determination of carcinogenic potency of chemical compounds combined with simultaneous differentiation of structure of examined compounds, sometimes leads to contradictory conclusions. Correlation between mutagenic and carcinogenic activity of some compounds is also sometimes questionable. Modern molecular biology should allow for elaborating a method which would give a satisfactory and reliable answer to the fundamental question: is a specific compound carcinogenous for a human organism? And if so - to what extent?
Źródło:
Environmental Biotechnology; 2005, 1, 1; 16-28
1734-4964
Pojawia się w:
Environmental Biotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and fungistatic activity of aryl-substituted naphthalene- and indene-2-carbonitriles
Autorzy:
Kozik, B
Burgieł, Z. J.
Sepioł, J. J.
Wilamowski, J.
Łuczyński, M. K.
Góra, M.
Powiązania:
https://bibliotekanauki.pl/articles/363192.pdf
Data publikacji:
2006
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
grzyby fitopatogenne
WWA
aktywność fungistatyczna
ochrona roślin
phytopathogenic fungi
PAHs
fungistatic activity
plant protection
Opis:
4-Aryl-substituted 1-aminonaphthalene-2-carbonitriles and 3-phenyl-1-oxo-1H-indene-2-carbonitriles were prepared in a two--step synthesis from appropriate carbonyl compounds and were evaluated in vitro for growth-inhibiting activity against some phytopathogenic fungi: Fusarium culmorum, Penicillium expansum, Botrytis cinerea and Alternaria species. The results were compared with the activity of a commercial fungicide - captan. The highest fungistatic activity was revealed by 1-amino-4-phenylnaphthalene-2-carbonitrile. An efficient synthesis of 1-amino-4-arylnaphthalene-2-carbonitriles involves condensation of diarylacetaldehydes or 1,1-diarylacetones with malonodinitrile and cyclization of the obtained aryl-ylidenemalonodinitriles in concentrated sulfuric acid. The benzannulation reaction is accompanied by a quasi-aromatic rearrangement. The indenone derivatives were synthesized in the same manner from substituted benzophenones. As the formation of five-membered ring during the cyclization of diarylmethylidenemalonodinitriles was less effective, the rearrangement was not observed.
Źródło:
Environmental Biotechnology; 2006, 2, 1; 20-25
1734-4964
Pojawia się w:
Environmental Biotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coulomb versus Madelung Gap: Ordering in a System of Point Charges
Autorzy:
Sobkowicz, P.
Wilamowski, Z.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1929618.pdf
Data publikacji:
1993-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
72.20.Fr
Opis:
Spatial correlations of impurity charges in a mixed valence regime are studied with the use of Monte Carlo simulations. The influence of various kinds of disorder on the one-particle density of states is determined. A continuous transitions from a "soft" Coulomb gap (density of states vanishing only at the chemical potential) to a "hard" gap (with a finite range of energies with vanishing density of states) is found, driven by decreasing amount of built-in disorder in the system. The "hard" Coulomb gap resembles the Madelung gap, found in crystalline arrangements of charges. The similarity reflects the fact that both the Coulomb and Madelung gaps are manifestations of the same phenomenon, resulting from ordering of the positions of point charges, the only difference being the range of correlations.
Źródło:
Acta Physica Polonica A; 1993, 84, 3; 515-518
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Potential Fluctuations in HgSe:Fe,Ga - a Numerical Study
Autorzy:
Sobkowicz, P.
Wilamowski, Z.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1861521.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
Opis:
We study spatial correlation of donor charges in HgSe:Fe,Ga using a few simple quantities (mean electrostatic energy of various donor sites, fluctuations of the electrostatic potential). The study uses Monte Carlo simulation techniques. We are able to indicate general trends in the behavior of the correlation when proportion of correlating (Fe^{3+}) and noncorrelating (Ga) charged centers in the sample is changed.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 645-648
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Integrated biostratigraphy and carbon isotope stratigraphy of the Upper Jurassic shallow water carbonates of the High-Tatric Unit (Mały Giewont area, Western Tatra Mountains, Poland)
Autorzy:
Pszczółkowski, A.
Grabowski, J.
Wilamowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2060534.pdf
Data publikacji:
2016
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
biostratigraphy
carbon isotope stratigraphy
Raptawicka Turnia Limestone Formation
Upper Jurassic
High-Tatric Succession
Tatra Mts.
Opis:
New biostratigraphical and carbon isotope data are presented for the Upper Jurassic limestones of the Raptawicka Turnia Limestone Formation (High Tatric unit, Western Tatra Mountains, Poland) from the Mały Giewont area. The Kimmeridgian, lower Tithonian and lower part of the upper Tithonian have been identified on the basis of calcareous dinocysts and calpionellids. Eight microfossil biozones are distinguished: acme Fibrata, acme Parvula, Moluccana, Borzai, Tithonica acme Pulla(?), Malmica, Chitinoidella and Crassicollaria (pars). The Kimmeridgian/Tithonian boundary is indicated at the top of the Borzai Zone 76 m above the base of the Raptawicka Turnia Limestone Formation. The microfossil stratigraphy suggests the late Early Kimmeridgian age (acme Parvula Zone) of the ammonites described by Passendorfer (1928). The taxon Taramelliceras ex gr. compsum found 14 m above those ammonites is Late Kimmeridgian in age. Seven microfacies types (MF) are identified in the Upper Jurassic limestones of the Mały Giewont area. The Bositra-Saccocomidae MF occurs across the Lower-Upper Kimmeridgian boundary. The planktonic and benthic foraminifera occur in the Upper Jurassic deposits of the Raptawicka Turnia Limestone Formation. The genera Lenticulina Lamarck and Spirillina Ehrenberg are common in the Kimmeridgian and Tithonian limestones. The palaeobathymetric evolution of the Kimmeridgian-Tithonian deposition recorded in the Mały Giewont sections reveals: the transgressive episode at the Lower/Upper Kimmeridgian boundary interval, the transgression peak during the Early Tithonian (Malmica Zone) and gradual shallowing of the High-Tatric swell in the Late Tithonian. Integrated isotope stratigraphy and biostratigraphy enabled correlation with the pelagic section of the Sub-Tatric succession in the Długa Valley section. The middle part of the Raptawicka Turnia Limestone Formation (Upper Kimmeridgian) might be correlated with the upper part of the Czajakowa Radiolarite Formation (red radiolarites) and Czorsztyn Formation in the Długa Valley section. The upper part of the Raptawicka Turnia Limestone Formation of Early Tithonian age corresponds mostly to the Jasenina Formation. The overall similarity of the δ13C decreasing values recorded in the Kimmeridgian–earliest Tithonian interval of the Mały Giewont (this study) and Długa Valley sections indicates that the generally shallow-water deposits of the Raptawicka Turnia Limestone Formation accumulated below the zone influenced by changes in the composition of marine water caused, for instance, by intense rainfalls.
Źródło:
Geological Quarterly; 2016, 60, 4; 893--918
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monte Carlo Simulations of Spatial Correlations of Charged Centers in δ-Doped Layers
Autorzy:
Sobkowicz, P.
Wilamowski, Z.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1921559.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
73.20.Dx
71.45.Gm
Opis:
Results of Monte Carlo simulations of a 2D system of charged donors are presented. They enable to study the effects related to a spatial correlation of donor charges located on a random donor matrix. A qualitative difference between DX$\text{}^{+}$ and DX¯ models is observed. In the first case, strong temperature dependence of the correlations and a "freezing-like" behaviour is found. The origin of the freezing is traced to the random distribution of donor sites by comparing the system with a liquid-like model where the charges may assume arbitrary positions within a plane. In the second case only nearest-neighbour correlations are observed. The simulations have direct application in analysis of the behaviour of the DX centers in the GaAs planarly doped with Si.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 645-648
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Localized Spin Relaxation Due To Coupling To Effective Mass States
Autorzy:
Wilamowski, Z.
Dmochowski, J. E.
Jantsch, W.
Powiązania:
https://bibliotekanauki.pl/articles/1968446.pdf
Data publikacji:
1997-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Jm
75.50.-y
Opis:
The EPR of residual Mn in CdF$\text{}_{2}$ doped with Y, In and Ga is investigated. Although these donors are barely seen in EPR, they manifest themselves by a new effect: a drastic resonant reduction in the longitudinal relaxation rate of Mn which occurs only if the Zeeman splitting of the two subsystems coincide. In this situation, the saturation of those of the six Mn hyperfine lines is weakened which coincide with the shallow donor resonance.
Źródło:
Acta Physica Polonica A; 1997, 92, 5; 1055-1058
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Consequences of Spatial Fluctuation of Coulomb Potential in AlGaAs with DX Centers
Autorzy:
Wilamowski, Z.
Kossut, J.
Jantsch, W.
Ostermayer, G.
Powiązania:
https://bibliotekanauki.pl/articles/1890983.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Dp
71.45.Jp
72.80.Ey
Opis:
Electric charges on randomly distributed impurities in semiconductors produce a spatially fluctuating potential. When the impurities are partially filled, their occupancy is not random but there appears a spatial correlation of the impurity charges appearing due to the inter-impurity Coulomb interactions. We show that when these interactions are taken into account then (i) the activation energy of the electron concentration, (ii) thermal emission kinetics, (iii) capture kinetics, (iv) persistent photoconductivity kinetics and (v) the electron mobility (in a steady state as well as during transients) in GaAlAs:Si can be explained in a consistent way. The energy diagram con cerning the DX center levels with respect to minima of the conduction band as well as the capture and emission barriers (including the effect of the alloy splitting) is constructed within an approach making use of the notion of the impurity self-screening.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 385-388
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial Correlation of Impurity Charges Induced by Coulomb Interactions - Application to DX Centers in GaAs
Autorzy:
Kossut, J.
Wilamowski, Z.
Dietl, T.
Świątek, K.
Powiązania:
https://bibliotekanauki.pl/articles/1877485.pdf
Data publikacji:
1991-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ey
72.20.Dp
71.55.Eq
Opis:
The electron mobility enhancement observed in heavily doped GaAs under hydrostatic pressure is interpreted in terms of spatial correlation between the donor charges within partially occupied system of impurities induced by strong inter-donor Coulomb interaction. A simple analytic theory is given for both DX$\text{}^{0}$ and DX$\text{}^{-}$ models of the impurity state. The mobility is shown to increase together with pressure in both models. Estimates of the energy of the DX level are strongly perturbed by the inter-donor Coulomb interactions.
Źródło:
Acta Physica Polonica A; 1991, 79, 1; 49-58
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrically Detected Magnetic Resonance
Autorzy:
Fedorych, O. M.
Wilamowski, Z.
Jantsch, W.
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2038127.pdf
Data publikacji:
2004-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.30.Pk
72.25.Rb
73.21.Fg
Opis:
We compare the results of electrically detected magnetic resonance in a 2D electron gas in Si/SiGe quantum wells with transport and magnetic resonance measurements on ferromagnetic Ga$\text{}_{1-x}$Mn$\text{}_{x}$As. The results lead us to the conclusion that observation of electrically detected magnetic resonance is possible only in the case of a slow spin relaxation, where the microwave resonant absorption leads to a noticeable change of spin magnetization.
Źródło:
Acta Physica Polonica A; 2004, 105, 6; 591-598
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Scattering and the Band Structure of Mixed Crystals Hg$\text{}_{1-x}$Fe$\text{}_{x}$Se
Autorzy:
Skierbiszewski, C.
Wilamowski, Z.
Suski, T.
Kossut, J.
Witkowska, B.
Powiązania:
https://bibliotekanauki.pl/articles/1923803.pdf
Data publikacji:
1992-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.Fk
72.20.Fr
72.80.Jc
Opis:
In this paper the dependence of the band structure and the electron scattering mechanisms on the molar fraction x are studied in Hg$\text{}_{1-x}$Fe$\text{}_{x}$Se. The crossover from the zero-gap band to the open band-gap configuration at x ≈ 0.08 is predicted. We explain the drop of the electron mobility for x > 0.002 by the alloy scattering mechanism.
Źródło:
Acta Physica Polonica A; 1992, 82, 5; 809-812
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ferromagnetic, Ferrimagnetic and Spin-wave Resonances in GaMnAs Layers
Autorzy:
Fedorych, O.
Byszewski, M.
Wilamowski, Z.
Potemski, M.
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2035590.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
76.30.Fc
75.50.Pp
75.30.Gw
Opis:
Molecular beam epitaxy grown Ga$\text{}_{1-x}$Mn$\text{}_{x}$As layers were investigated by means of magnetic resonances. With an increase in Mn concentration, x, the spectrum changes from the (i) paramagnetic one, with resolved fine and hyperfine structures, typical of S=5/2 spin of substitutional Mn$\text{}^{2+}$ ions, for very diluted alloy, via (ii) paramagnetic spectrum, where the fine and hyperfine structures are averaged by a long range Mn$\text{}^{2+}$-Mn$\text{}^{2+}$ exchange coupling, (iii) single, isotropic line of ferromagnetic resonance. Insulator to metal transition is accompanied with occurrence of (iv) a very complex spectrum of the ferrimagnetic resonance, accompanied with the well-resolved spin wave resonance. Reentrance to insulator phase for the most condensed alloys is accompanied with the reentrance to (v) ferromagnetic phase. The data confirm that the effective mass holes transfer the exchange interaction between localized Mn$\text{}^{2+}$ spins.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 617-625
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electric Dipole and Current Induced Spin Resonances of Shallow Donor in ZnO
Autorzy:
Michaluk, E.
Błoniarz, J.
Pabich, M.
Wilamowski, Z.
Mycielski, A.
Powiązania:
https://bibliotekanauki.pl/articles/2046940.pdf
Data publikacji:
2006-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Gs
76.30.-v
71.70.Ej
Opis:
In this paper we present our observation of electric dipole spin resonance and current induced spin resonance in ZnO bulk crystals, both effects result from spin-orbit coupling. Electric dipole spin resonance originates from admixture of spin state due to spin-orbit interaction which leads to probability of spin-flip caused by electric component of microwave field. In current induced spin resonance phenomenon the electric component of microwave field induces electron motion leading to mean ac spin-orbit field that acts on electron spin. Spin-orbit interaction can be described in terms of the Rashba field, an effective magnetic field that induce spin resonance. In contrast to magnetic and electric dipole spin resonances the current induced resonance is characterized by dispersive-like line shape.
Źródło:
Acta Physica Polonica A; 2006, 110, 2; 263-270
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Resonance Studies of the Origin of Ferromagnetism in Ga$\text{}_{1-x}$Mn$\text{}_{x}$As
Autorzy:
Fedorych, O. M.
Wilamowski, Z.
Potemski, M.
Byszewski, M.
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2036029.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
76.30.Fc
75.50.Pp
75.30.Gw
Opis:
Different types of magnetic resonance observed in Ga$\text{}_{1-x}$Mn$\text{}_{x}$As reflect three different magnetic phases: para-, ferro-, and ferrimagnetic. Ferromagnet is characterized by single isotropic resonance line. A complex spectrum in ferrimagnet can be described by g factor equal to 1.44 and a sum of an axial and cubic anisotropy field. The axial field is by an order of magnitude greater than the cubic one. The complex structure of ferrimagnetic resonance is attributed to spin-wave resonance. Quantitative analysis of the dispersion of spin wave shows that the range of exchange coupling is very long, of the order of 25 nm, while spin-wave stiffness and the total exchange field are very small. The exchange field as evaluated from spin wave is by two orders of magnitude smaller than the Zener field corresponding to the critical temperature.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 607-612
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pressure Study of Charged Donor Ordering in HgSe Doped with Iron and Gallium
Autorzy:
Skierbiszewski, C.
Suski, T.
Kossut, J.
Wilamowski, Z.
Dobrowolski, W.
Witkowska, B.
Powiązania:
https://bibliotekanauki.pl/articles/1891020.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.10.Fk
72.20.Fr
72.80.Jc
Opis:
Transport experiments (Hall effect and conductivity) under hydrostatic pressure up to 1 GPa at liquid helium temperatures on HgSe: Fe, Ga (N$\text{}_{Fe}$ = 2 x 10$\text{}^{19}$ cm$\text{}^{-3}$; 0 ≤ N$\text{}_{Ga}$ ≤ 10$\text{}^{19}$ cm$\text{}^{-3}$) were performed. The results show that the gallium co-doping of HgSe:Fe decreases the degree of spatial correlations between charged impurities. Under the hydrostatic pressure, used as a tool for changing the ratio of the charged to neutral impurities, this effect is even more pronounced. A qualitative agreement between the calculation within the short-range correlation model and our experimental data is achieved.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 401-404
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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