Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "T. D." wg kryterium: Wszystkie pola


Tytuł:
Critical Fluctuations and 1/f$\text{}^{α}$-Activity of Neural Fields Involving Transmission Delays
Autorzy:
Hutt, A.
Frank, T. D.
Powiązania:
https://bibliotekanauki.pl/articles/2044577.pdf
Data publikacji:
2005-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.19.La
05.40.Ca
02.30.Ks
05.70.Jk
Opis:
This work studies the stability and the stochastic properties of neural activity evoked by external stimulation. The underlying nonlocal model describes the spatiotemporal response dynamics of neural populations involving both synaptic delay and axonal transmission delay. We show that the linear model recasts to a set of affine delay differential equations in spatial Fourier space. Besides a stability study for general kernels and general external stimulation, the power spectrum of evoked activity is derived analytically in the case of external Gaussian noise. Further applications to specific kernels reveal critical fluctuations at Hopf- and Turing bifurcations and allow the numerical detection of 1/f$\text{}^{α}$fluctuations near the stability threshold.
Źródło:
Acta Physica Polonica A; 2005, 108, 6; 1021-1040
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ab Initio Study of the $\text{}^{57}Fe$ Electric Field Gradient in $(FeAl)_{1-x}T_x$ (T = 3d Element) Dilute Alloys with B2-Type Structure
Autorzy:
Michalecki, T.
Hanc, A.
Deniszczyk, J.
Borgieł, W.
Powiązania:
https://bibliotekanauki.pl/articles/1811576.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Be
71.20.Lp
75.50.Bb
76.80.+y
Opis:
We present an ab initio study of the electric field gradient at Fe nuclei in the series of $(FeAl)_{1-x}T_x$ dilute alloys with B2-type crystal structure. The ternary additions T, of concentration x ≈ 0.06, from the group of 3d-type transition metals (Ti, V, Cr, Mn, Co, Ni, Cu) are considered. Lattice, local valence electron (3d, 4p) and weakly bound 3p core electron contributions to electric field gradient are separated out and discussed in the context of the T-atom site preference and changes of the electronic structure upon alloying. Contrary to earlier reports, we found that for most Fe nuclei the dominant contribution comes from the d-type valence electrons cancelled partially by the 3p and 4p electric field gradients which are both of opposite sign to that of the 3d one. The shielding effect of 3p semicore electrons is found and related to the electric field gradient contributed by the local valence electrons.
Źródło:
Acta Physica Polonica A; 2008, 114, 6; 1483-1491
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pressure-Dependent Coupling of the $\text{}^{3}$A$\text{}_{2}$(F) and $\text{}^{1}$T$\text{}_{2}$(D) States of Ni$\text{}^{2+}$ in ZnS and ZnSe
Autorzy:
Wasik, D.
Baj, M.
Liro, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1886737.pdf
Data publikacji:
1991-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
Opis:
We have investigated two close-lying $\text{}^{3}$A$\text{}_{2}$(F) and $\text{}^{1}$T$\text{}_{2}$(D) states of Ni$\text{}^{2+}$ impurity in ZnS and ZnSe. These states are strongly coupled to each other via the spin-orbit interaction and therefore, small variations of their energies induced by pressure have significantly changed absorption spectra related to them. In order to give a good interpretation to the experimental results we took into account the interaction between both states, their coupling to the lattice vibrations and the pressure-dependent separation between them.
Źródło:
Acta Physica Polonica A; 1991, 79, 2-3; 319-322
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Epitaxial Layers Versus Bulk Single Crystals of GaN. Temperature Studies of Lattice Parameters and Energy Gap
Autorzy:
Teisseyre, H.
Perlin, P.
Leszczyński, M.
Suski, T.
Dmowski, L.
Grzegory, I.
Porowski, S.
Jun, J.
Moustakas, T. D.
Powiązania:
https://bibliotekanauki.pl/articles/1873040.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
65.70.+y
78.50.Ge
78.66.Fd
Opis:
Gallium nitride epitaxial layer grown by molecular beam epitaxy and bulk crystal grown at high pressure were examined by using X-ray diffraction methods, and by optical absorption at a wide temperature range. The free electron concentration was 6 × 10$\text{}^{17}$ cm$\text{}^{-3}$ for the layer and about 5 × 10$\text{}^{19}$ cm$\text{}^{-3}$ for the bulk crystal. The experiments revealed a different position of the absorption edge and its temperature dependence for these two kinds of samples. The structural examinations proved a significantly higher crystallographic quality of the bulk sample. However, the lattice constants of the samples were nearly the same. This indicated that a rather different electron concentration was responsible for the different optical properties via Burstein-Moss effect.
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 403-406
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum States and Number-Phase Uncertainty Relations Measured by Optical Homodyne Tomography
Autorzy:
Raymer, M. G.
Smithey, D. T.
Beck, M.
Cooper, J.
Powiązania:
https://bibliotekanauki.pl/articles/1931411.pdf
Data publikacji:
1994-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.65.Bz
42.50.Wm
Opis:
Experiments have been performed to determine the Wigner distribution and the density matrix (and for pure states the wave function) of a light mode, by using tomographic inversion of a set of measured probability distributions for quadrature amplitudes. From these measurements the quantum distributions of optical phase and photon number have been obtained. The measurements of quadrature-amplitude distributions for a temporal mode of the electromagnetic field are carried out using balanced homodyne detection. We refer to this new method as optical homodyne tomography. Given the measured density matrix, one can experimentally infer any of the various quantum distributions of optical phase, in particular the Pegg-Barnett (or, equivalently, Shapiro-Shepard) phase distribution, the marginal Wigner distribution, and the Vogel-Schleich operational phase distribution. We have used this approach to make measurements of the number-phase uncertainty relation for coherent-state fields. The coherent states do not attain the minimum value for the number-phase uncertainty product, as set by the expectation value of the commutator of the number and phase operators; this is true theoretically and experimentally.
Źródło:
Acta Physica Polonica A; 1994, 86, 1; 71-80
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature Dependence of the Self-Broadened 540.06 nm Neon Line
Autorzy:
Leo, P. J.
Mullamphy, D. F. T.
Peach, G.
Venturi, V.
Whittingham, I. B.
Powiązania:
https://bibliotekanauki.pl/articles/1968841.pdf
Data publikacji:
1998-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
32.70.Jz
34.20.Cf
Opis:
Quantum close-coupled calculations of the collisional self-broadening of the 540.06 nm neon line (3s[3/2]$\text{}_{1}$-3p'[1/2]$\text{}_{0}$) are presented for temperatures from 70 K to 900 K. These calculations are based on the quantum-mechanical impact theory of Baranger and represent the interatomic interaction by adiabatic molecular potentials calculated using model potentials for the electron- atom and atomic core-core interactions. The calculated widths and shifts vary smoothly with temperature and are accurately given across the temperature range by fourth order polynomial fits.
Źródło:
Acta Physica Polonica A; 1998, 93, 3; 459-464
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Pressure on Superconductivity in $YB_{6}$
Autorzy:
Gabáni, S.
Pristáš, G.
Takáčová, I.
Flachbart, K.
Gažo, E.
Mori, T.
Braithwaite, D.
Samuely, P.
Powiązania:
https://bibliotekanauki.pl/articles/1371520.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.70.Ad
74.25.F-
62.50.-p
Opis:
Magnetoresistivity measurements on a superconducting system of $YB_{6}$ ($T_c$ ≈7.5 K) down to 60 mK at hydrostatic pressures up to 47 kbar are presented. The superconducting transition temperature, as well as the third critical field $H_{c3}$ reveal a linear decrease with increasing pressure with slopes of d ln $H_{c3}$/dp=-1.1 %/kbar, and d ln $T_c$/dp=-0.59 %/kbar. From the latter a critical pressure, $p_c$ ≈ 170 kbar, at which $T_c$ vanishes, is determined.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 340-341
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Atomic Order and the Interaction of Electronic and Magnetic Subsystems in Epitaxial LaSr(Ca)MnO Films
Autorzy:
Okunev, V. D.
Samoilenko, Z. A.
D'yachenko, T.
Abal'oshev, A.
Baran, M.
Gierłowski, P.
Lewandowski, S. J.
Szewczyk, A.
Szymczak, R.
Powiązania:
https://bibliotekanauki.pl/articles/2037110.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Kz
75.47.Lx
61.50.Ks
Opis:
We have investigated the structure, and electric, optical, and magnetic properties of LaSr(Ca)MnO films containing atomic clusters of various types coherently built into the basic crystallographic matrix. Below the transition to the metallic state, the electrical conductivity of the films is determined by tunneling of charge carriers between metallic clusters. We have found that for each sample there exists a threshold value of magnetic ordering, above which the magnetic subsystem starts to affect actively the film conductivity. The observed increase of conductivity with decreasing temperature is caused by the fact that in the process of magnetic ordering of the samples the cluster size and concentration of metallic phase increase. Experimental results are in agreement with theoretical calculations.
Źródło:
Acta Physica Polonica A; 2004, 105, 1-2; 121-126
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mac Lane Method for Determination of Extensions of Finite Groups. II. An Example for the Dihedral Group D$\text{}_{2}$
Autorzy:
Lulek, T.
Chatterjee, R.
Powiązania:
https://bibliotekanauki.pl/articles/1920926.pdf
Data publikacji:
1992-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.20.+b
02.40.+m
03.20.+i
11.30.Er
Opis:
The Mac Lane method of classification and construction of all extensions of a group Q by an Abelian group T is demonstrated on the case Q = D$\text{}_{2}$, T = C$\text{}_{2}$. Constructions involving free groups and operator homomorphisms are performed in detail, and the complete list of resulting extensions is given. It is shown that there are 8 classes of gauge equivalency, and they fall into 4 classes of isomorphism. The role of gauge transformations is pointed out. Physical contexts of various constructions are reviewed. A comparison with the direct cohomology definitions is performed.
Źródło:
Acta Physica Polonica A; 1992, 82, 3; 395-406
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ion Microscopy and Tomography
Autorzy:
Butz, T.
Lehmann, D.
Reinert, T.
Spemann, D.
Vogt, J.
Powiązania:
https://bibliotekanauki.pl/articles/2028912.pdf
Data publikacji:
2001-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.75.Ak
72.20.My
29.30.Kv
Opis:
The use of light ions for microscopy and tomography is illustrated by a variety of recent applications in materials and life sciences at the Leipzig high-energy ion-nanoprobe LIPSION with a short comparison to other microscopic techniques. The versatility of ion techniques is exemplified by Rutherford backscattering spectrometry maps of thin films of solar cell materials, particle induced X-ray emission maps of manganese in ancient human bones, particle induced X-ray emission on single aerosol particles withμm size, and scanning transmission ion microscopy and tomography on pigs knee cartilage. Finally, the design of a single ion single living cell bombardment facility is sketched for studies of the cellular response and microdosimetry.
Źródło:
Acta Physica Polonica A; 2001, 100, 5; 603-613
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Study of ZnTe-Based 2D and 0D Photonic Structures Containing CdTe/ZnTe Quantum Dots
Autorzy:
Jakubczyk, T.
Kazimierczuk, T.
Golnik, A.
Bienias, P.
Pacuski, W.
Kruse, C.
Hommel, D.
Kłopotowski, Ł.
Wojtowicz, T.
Gaj, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791336.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Pt
Opis:
We report on an optical study of ZnTe-based microcavity and micropillars. Angle-resolved reflectivity studies confirm a high quality of the investigated structure by setting the lower bound on the quality factor Q ≥ 1000, determined from normal-incidence reflection spectra. In a microphotoluminescence study, micropillar modes are observed at temperatures of the order of tens of kelvins. For structures grown by a complex growth procedure at two different MBE facilities, an enhancement of photoluminescence in the cavity mode is observed.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 888-889
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performances of Nanosecond Pulsed Discharge
Autorzy:
Matsumoto, T.
Wang, D.
Namihira, T.
Katsuki, S.
Akiyama, H.
Powiązania:
https://bibliotekanauki.pl/articles/1807933.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.80.Hc
Opis:
The conventional methods such as selective catalytic reduction method, electron beam method and lime-gypsum method could not treat exhaust gases completely. In addition, the energy efficiency and the cost of the conventional ways are still unfavourable. In recent years, the pollution control techniques using electric discharge plasmas which attract attention as the low cost and high energy efficient exhaust gas treatment methods, have been widely studied. In our laboratory, pulsed streamer discharge plasmas which are one of the non-thermal plasmas have been used to treat exhaust gases. Since a pulse width of applied voltage has a strong influence on the energy efficiency of the removal of pollutants, the development of a short pulse generator is of paramount importance for practical applications. In this work, nanosecond pulse generator which can output the 5 ns pulsed voltage is developed. In addition, the exhaust gas treatment and the ozone production by nanosecond pulse generator were demonstrated.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 1101-1103
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Acoustic Wave Propagation in a Power Transformer Model
Autorzy:
Wotzka, D.
Boczar, T.
Zmarzły, D.
Powiązania:
https://bibliotekanauki.pl/articles/1807760.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.80.-s
43.28.Js
Opis:
Analyses of acoustic wave propagation in a model power transformer are presented in the paper. The acoustic wave is induced by partial discharges that are simulated at predefined coordinates in the core and winding. Propagation of the numerical calculated acoustic wave is analyzed within the transient state. Achieved results indicate that the space and time distributions of the acoustic pressure depend on the induction position. Furthermore, a greater pressure gradient is observed in domains with higher speed of sound while the largest amplitude occurs at the vicinity of the induction position.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 428-431
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Simulation of Acoustic Wave Propagating in a Spherical Object Filled with Insulating Oil
Autorzy:
Wotzka, D.
Zmarzły, D.
Boczar, T.
Powiązania:
https://bibliotekanauki.pl/articles/1506871.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.60.Lj
Opis:
Results of a numerical simulation of an acoustic wave that propagates in a spherical object filled with insulating oil are presented in the paper. The sinusoidal acoustic wave is generated by an electro-acoustic transducer mounted in the middle of the object. Presented results depict acoustic pressure distribution within the transient and the steady states in a two-dimensional object. Furthermore, comparison of short time simulations adapting different mesh element size is presented.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1272-1275
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Ferromagnetic p-d Exchange in Diluted Magnetic Semiconductors
Autorzy:
Blinowski, J.
Dietl, T.
Kacman, P.
Powiązania:
https://bibliotekanauki.pl/articles/1921558.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Pp
75.30.-m
71.70.-d
Opis:
The antiferromagnetic type of the interaction between the Γ$\text{}_{8}$-band electrons and the Mn$\text{}^{2+}$ ions in A$\text{}^{II}$B$\text{}^{IV}$ diluted magnetic semiconductors has been explained by invoking the p-d hybridization mechanism. In this paper it is shown that for particular electronic configurations of the magnetic ions in diluted magnetic semiconductors the p-d hybridization can lead to a ferromagnetic interaction between the valence-band electrons and the localized spins. This happens when all the one-electron d-orbitals which hybridize with p-band states are empty (e.g., as in Sc$\text{}^{2+}$ and Ti$\text{}^{2+}$ ions). The appropriate p-d Hamiltonian is derived and the ferromagnetic exchange constants are evaluated.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 641-644
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies