Informacja

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

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "41.20.Jb" wg kryterium: Temat

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 40
Tytuł:
New Results in Chaotic Time-Reversed Electromagnetics: High Frequency One-Recording-Channel Time-Reversal Mirror
Autorzy:
Anlage, S. M.
Rodgers, J.
Hemmady, S.
Hart, J.
Antonsen, T. M.
Ott, E.
Powiązania:
https://bibliotekanauki.pl/articles/2047818.pdf
Data publikacji:
2007-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.50.De
05.45.Mt
41.20.Jb
42.65.Hw
Opis:
We experimentally demonstrate a new electromagnetic one-recording-channel time-reversal mirror that can operate at high frequencies and high bandwidths. The experiments are carried out in a 1 m$\text{}^{3}$ ray-chaotic enclosure using two simple antennas. The input is a 7.0 GHz signal that is amplitude modulated with a 60 ns long pulse. The time-reversal focused signal has a peak-signal-to-noise ratio of about 9 dB, and is very sensitive to small perturbations to the ray-chaotic enclosure. The results are consistent with expectations for single-recording-channel time-reversal mirrors, and establish a new platform for study of fundamental issues in time-domain wave chaos, as well as novel applications.
Źródło:
Acta Physica Polonica A; 2007, 112, 4; 569-574
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Consequences of Unit Cell Design in Metamaterial Perfect Absorbers
Autorzy:
Bagci, F.
Akaoglu, B.
Powiązania:
https://bibliotekanauki.pl/articles/1398784.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Xj
41.20.Jb
Opis:
Metamaterials are a new class of composite materials with unusual properties that allow controlling of electromagnetic waves by properly engineering the response functions, which are not observed in constituent materials. However, since absorption of metamaterials is mainly based on electromagnetic resonances, the operating bandwidth is relatively narrow. Utilization of more than a single metallic structure with different geometrical parameters in each unit cell is a common way of accomplishing multiple band and/or broadband absorption. There are two usual approaches for this purpose: (a) multilayer unit cell design where metallic structures on dielectric substrate are stacked one on top of the other; (b) side by side unit cell design where metallic structures are distributed on a dielectric substrate. However, to the best of our knowledge, these two different approaches are not comparatively investigated. In this study, we propose metamaterial-based perfect absorbers with two different unit cell designs and simulate transmittances, reflectances and absorbances for each design by a commercial electromagnetic solver, CST Microwave Studio. It is found that each design has its own advantages in terms of device thickness, absorption bandwidth and angular dependence, which might be severely important for particular purposes.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 792-796
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time Delay in Thin Dielectric Slabs with Saturable Nonlinearity
Autorzy:
Beličev, P.
Ilić, I.
Radovanović, J.
Milanović, V.
Hadžievski, Lj.
Powiązania:
https://bibliotekanauki.pl/articles/1808066.pdf
Data publikacji:
2009-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.65.Xp
41.20.Jb
42.25.Bs
42.70.Nq
Opis:
Time delays for an intense transverse electric wave propagating through a slab with saturable nonlinearity are investigated. The nonlinearity is assumed in a form of the Vinetskii-Kukhtarev model, which is relevant for the slabs made of nonlinear photorefractive crystals, such as GaAs and $LiNbO_3$, which feature a saturable nonlinearity. The expressions for the group delay and the dwell time are derived and the relation between them is studied. It is shown that the difference between them has three different contributions. The first one corresponds to the self-interference associated with the dispersion of the medium surrounding the slab. The other two appear due to the nonlinearity of the slab and oblique incidence of the transverse electric wave. All the results are compared with the case of dielectric slabs with cubic (Kerr) nonlinearity.
Źródło:
Acta Physica Polonica A; 2009, 115, 4; 834-837
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mode Conversion in SiO₂/ZrO₂ Layer Doped with Magnetic CoFe₂O₄ Nanoparticles
Autorzy:
Bouras, M.
Hocini, A.
Powiązania:
https://bibliotekanauki.pl/articles/1401325.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
04.30.Nk
41.20.Jb
92.60.Ta
Opis:
This paper describes the TE-TM mode conversion in a magneto-optical layer made by a SiO₂/ZrO₂ layer doped with magnetic CoFe₂O₄ nanoparticles. The mode conversion is caused by the Faraday rotation if the magnetization is aligned along the z-axis, parallel to mode propagation. The properties of this phenomenon are simulated using the full-vectorial beam propagation method (BPM). The simulation results show clearly the influence of two parameters in such devices, the first one is the off-diagonal component of tensor that enhances the rotation and the second one, the imaginary diagonal tensor (parameters K ) which makes it suffering from absorption. This result of simulation is an important step to achieve a monolithic integration of optical isolators.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1191-1194
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Earths Magnetic Field on the HF Radio Wave Modes at the Heated Subionosphere
Autorzy:
Canyilmaz, M.
Atici, R.
Guzel, E.
Powiązania:
https://bibliotekanauki.pl/articles/1400161.pdf
Data publikacji:
2013-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
94.20.Bb
94.20.ws
94.20.wj
41.20.Jb
84.40.-x
Opis:
In this study, the effect of the actual geometry of the magnetic field on the electron temperature has been investigated daily and seasonally for the electromagnetic wave travelling at subionosphere. The electron energy balance equation has been obtained by using the ideal gas approximation. The results show that there are notable differences between the two situations (B ∥ k ∥ z and B real, ∥ z). According to our theoretical study, the maximum changes are shown at L- and R-mode, small effect on X-mode and no variation on O-mode due to the real geometry of the magnetic field. Besides, the heights of the maximum points are changeable daily and seasonally for all modes at the subionosphere.
Źródło:
Acta Physica Polonica A; 2013, 123, 4; 786-790
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sharp-rejection, wide and deep stopband low pass filter design using open stubs and DGS patterns
Autorzy:
Challal, M.
Boulakroune, M.
Powiązania:
https://bibliotekanauki.pl/articles/1061519.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.-q
41.20.Jb
11.10.-z
Opis:
A sharp rejection, wide and deep stopband microstrip low pass filter is investigated in this paper. The proposed low pass filter is composed of three defected ground structure patterns and four open stubs. Simulated results verify that the filter has a sharpness factor of 0.9, a low insertion loss of 0.65 and a return loss less than 15 dB. Moreover, a wide stopband at 20 dB rejection ranging from 4.55 GHz to 11.62 GHz is accomplished. The filter presented in this work was compared with the previous works completed on low pass filter with sharp rejection. It has shown that the filter provides good performances in terms of sharp rejection, wide and deep rejection band and small passband insertion loss compared to those reported in the literatures.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 9-10
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency stop band in an air-voided ZnO photonic crystal: A dispersion diagram based design
Autorzy:
Chaturvedi, V.
Kumar Roy, M.
Powiązania:
https://bibliotekanauki.pl/articles/1075558.pdf
Data publikacji:
2016-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
01.65.+g
01.70.+w
41.20.Jb
78.20.-e
Opis:
Electromagnetic excitation, inside small volumes, results in perturbations which play an important role in the validation of theoretical formulations. Efforts to catch a glimpse of the action inside of the small space, can aid better thin film designs. In the non-linear anisotropic regime the results of such interactions provide important insights into the bulk level behavior of matter. Using this approach, a zinc oxide (ZnO) based photonic crystal is designed with spherical air voids. A Gaussian continuous wave excitation of the refractive index contrast (ZnO=1.9 and Air =1) photon waveguide generated thus, is characterized for the redistribution of electromagnetic field. When, centered at a specific wavelength (1.9 μ m), the graph of the frequencies that can exist inside the crystal, is plotted against the limited k-space vector. The dispersion diagram that emerges shows a band of frequency states that cannot exist inside such a design. Physically this constitutes a k-space which is devoid of any detectable disturbances. Crystallographically, the reduced Brilluoin zone can be used to make a thin layer of ZnO that can act as a frequency stop layer, in a real multilayered photoelectric device.
Źródło:
Acta Physica Polonica A; 2016, 130, 3; 683-687
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrafast Coherent Terahertz Spectroscopy in High Magnetic Fields and Directed Energy Flows in Quantum Dot Assemblies
Autorzy:
Crooker, S. A.
Barrick, T.
Hollingsworth, J. A.
Klimov, V. I.
Powiązania:
https://bibliotekanauki.pl/articles/2036883.pdf
Data publikacji:
2003-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.Re
41.20.Jb
73.21.La
78.47.+p
Opis:
We describe the design, construction, and use of fiber-coupled terahertz antennas for performing ultrafast coherent THz spectroscopy directly in the cryogenic bore of high-field magnets. With an aim towards measuring the high-frequency (100 GHz to 2000 GHz) complex conductivity of correlated electron materials in the regime of low temperatures and high magnetic fields, these miniature THz emitters and receivers are demonstrated to work down to 1.5 K and up to 18 T, for eventual use in higher-field magnets. Results from a variety of semiconducting and superconducting samples are presented. This paper also describes a separate effort towards achieving coupling between colloidal semiconductor nanocrystal quantum dots, wherein we realize and study inter-dot communication via resonant (Förster) energy transfer. We present studies of the dynamics of resonant energy transfer in monodisperse and energy gradient (layered) assemblies of CdSe nanocrystal quantum dots. Time- and spectrally-resolved photoluminescence data directly reveal the energy-dependent transfer rate of excitons from smaller to larger dots. Results from layered nanocrystal quantum dot assemblies demonstrate unidirectional energy flows, a first step towards artificial light-harvesting structures. Lastly, time-resolved studies at millikelvin temperatures elucidate the nature of ground-state"dark" excitons in these quantum dots.
Źródło:
Acta Physica Polonica A; 2003, 104, 2; 113-122
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Response of a Magnetic Fluid to Radio Frequency Electromagnetic Field
Autorzy:
Dolník, B.
Rajňák, M.
Cimbala, R.
Kolcunová, I.
Kurimský, J.
Balogh, J.
Džmura, J.
Petráš, J.
Kopčanský, P.
Timko, M.
Briančin, J.
Fabián, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032825.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
41.20.Gz
75.50.Mm
81.70.Ex
07.50.Hp
Opis:
Electromagnetic pollution generated by the electrical devices has been regarded as a new form of pollution, harmful to the society as air and water pollution. The operation of electronic devices in a polluted electromagnetic environment has caused electromagnetic interference to become important concerns. Devices that are vulnerable to interference must often be shielded to protect them from the effects of electromagnetic interference. In this work we describe an interaction of a magnetic fluid based on transformer oil with alternating magnetic field. The magnetic fluid was composed of a transformer oil and dispersed magnetite nanoparticles coated with oleic acid. Among the wide range of topics covered, we pay attention to an important field related to the absorption of electromagnetic field by magnetic fluid as a suitable candidate for applications where it is necessary to electrically isolate, remove excess of heat, and to shield electromagnetic fields. We present a method for the determination of shielding effectiveness of the magnetic fluid under high-frequency excitation conditions from 750 MHz to 3 GHz by means of magnetic near field measurements and analysis. Herein, we report the effect of magnetic volume fraction in the magnetic fluid and the effect of the sample thickness on the shielding effectiveness. We have found that the magnetic fluid has a frequency dependent "windows", characterized that either absorb the magnetic field, or facilitate penetration of the magnetic field through the barrier.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 946-948
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Shielding Effectiveness of a Magnetic Fluid in Radio Frequency Range
Autorzy:
Dolník, B.
Rajňák, M.
Cimbala, R.
Kolcunová, I.
Kurimský, J.
Džmura, J.
Petráš, J.
Zbojovský, J.
Kosterec, M.
Kopčanský, P.
Timko, M.
Powiązania:
https://bibliotekanauki.pl/articles/1030481.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
41.20.Gz
75.50.Mm
81.70.Ex
07.50.Hp
Opis:
This article builds on the previous work and describes the interaction of transformer oil-based magnetic fluid (MF) with the radio frequency (RF) magnetic near-field. Three prepared samples of the MF used as a barrier to magnetic near-field, consist of transformer oil and dispersed magnetite nanoparticles coated with oleic acid. We pay attention to the important area related to the electromagnetic field shielding by the MF. Such sample of the MF may be a good candidate for applications where it is necessary to simultaneously electrically isolate, remove the excess of heat and to shield electromagnetic interference (EMI). We present a method for the determination of shielding effectiveness (SE) of the MF under RF excitation conditions ranging from 500 MHz to 3 GHz. We report the effect of magnetic volume fraction in the MF and the effect of the sample thickness on the SE.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 585-587
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-Frequency Absorbing Performances of Carbonyl Iron/MnZn Ferrite/PVC Polymer Composites
Autorzy:
Dosoudil, R.
Ušáková, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032831.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.50.Bb
76.50.+g
75.78.-n
72.80.Tm
78.20.Ci
41.20.Jb
Opis:
We have prepared composite materials with a mixture of carbonyl iron (CI) and manganese-zinc ferrite (MnZn) as filler and polyvinylchloride (PVC) as polymer matrix, and then electromagnetic wave absorption properties of CI/MnZn/PVC composites have been studied in the frequency range from 10 MHz to 6.5 GHz. Increasing carbonyl iron loading (to the detriment of MnZn ferrite) results in the rise of permeability and magnetic resonance loss (especially in GHz frequency range) which leads to the shift of absorption peak towards lower frequency and to the decrease of matching thickness. On the contrary, increasing MnZn ferrite loading (to the detriment of carbonyl iron) results in higher absorption bandwidth. The obtained results indicate that the prepared flexible composites may be useful as thin and/or wideband microwave absorbers.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 687-689
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Electromagnetic-Acoustic Analogies in Energetic Relations for Waves Interacting with Material Surfaces
Autorzy:
Dukata, A.
Kapelewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1811519.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
Opis:
In the paper we consider propagation of a monochromatic surface electromagnetic field at the interface separating two semi-infinite media - a metamaterial (generally with complex permittivity and permeability) and a conventional dielectric medium. The metamaterial is treated as homogeneous and isotropic (it is so-called effective medium approximation). It is true for e.g. artificial metamaterials with negative dielectric permittivity and negative permeability in the microwave frequency range. The last materials are known as left handed and a conventional as right handed media. In this work the classical optical theorem is extended to the case of scattering of electromagnetic surface waves incident at the interface separating a left handed medium and a right handed dielectric medium. The analogous theorem is known in the scattering theory for elastic fields.
Źródło:
Acta Physica Polonica A; 2008, 114, 6A; A-69-A-73
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Shifter Operation of the Azimuthally Magnetized Coaxial Ferrite Waveguide
Autorzy:
Georgieva-Grosse, M.
Georgiev, G.
Powiązania:
https://bibliotekanauki.pl/articles/1419702.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.60.Lj
02.90.+p
41.20.-q
41.20.Jb
85.70.Ge
Opis:
The terms for operation of the coaxial waveguide, entirely filled with azimuthally magnetized latching ferrite, as a digital nonreciprocal phase shifter for the normal $TE_{01}$ mode, are found. They are classified as physical, mathematical and functional ones. The physical prerequisites are drawn from the phase curves of the structure and specify the boundaries of the interval in which it produces differential phase shift for a given numerical equivalent of the modulus of off-diagonal ferrite permeability tensor element. The mathematical condition brings the parameters of configuration together with certain roots of its characteristic equation, derived in terms of complex Kummer and Tricomi confluent hypergeometric functions and with the related to them positive real $L_2(c,ρ,n)$ numbers (c=3, 0<ρ<1, n=1). The functional criteria determine the borders of the domain of phase shifter operation of the geometry. These are functions, defined for a fixed central conductor thickness which express in normalized form the impact of the guide radius on the phase shift at the cut-off frequencies and at the envelopes, denoting the termination of the phase curves for negative ferrite magnetization from the side of higher frequencies. The same are reckoned, employing iterative methods, consisting in a repeated numerical solution of the equation mentioned, followed by a computation of the guide radius and phase constant of the wave and are plotted graphically. The influence of the parameters of transmission line on the area referred to is analyzed.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 63-70
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scattering of Light by Photonic Crystals
Autorzy:
Hoenders, B. J.
Doosje, M.
Knoester, J.
Powiązania:
https://bibliotekanauki.pl/articles/2030312.pdf
Data publikacji:
2002-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Qs
42.25.Fx
42.25.Bs
03.50.De
41.20.Jb
Opis:
A new method is developed to calculate the scattering of light at the surface of a photonic crystal. The problem is solved in terms of virtual surface-current distributions and the calculation takes full advantage of the infinite-space plane-wave expansion method for obtaining the photonic band structure. Working with surface currents makes the calculations less time-consuming by means of reduction of the dimensionality in the problem. The method is applied to a semi-infinite dielectric continuum and for semi-infinite two-dimensional photonic crystals of small and large dielectric contrast.
Źródło:
Acta Physica Polonica A; 2002, 101, 1; 133-146
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Imperfect Cloaking Devices Based on Metamaterials
Autorzy:
Isić, G.
Gajić, R.
Novaković, B.
Popović, Z. V.
Hingerl, K.
Powiązania:
https://bibliotekanauki.pl/articles/2047887.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
42.25.Fx
78.20.Ci
Opis:
Cloaking devices designed using the coordinate transform approach were shown to be realizable, at least in principle, within the realm of electromagnetic metamaterials. In this paper we investigate the strictness of conditions imposed on the parameters of metamaterial cloaks by calculating the degree of wave scattering when those parameters have variations with respect to theoretically ideal values. A simple idea is used to obtain analytic results for the case of the nonideal two-dimensional cloaking cylinder. Also, results of realistic finite element simulations of the Helmholtz equation are presented and it is found that they are in excellent agreement with the analytic results.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 1083-1088
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 40

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