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Tytuł:
Structure and Magnetic Properties of Iron/Iron-Oxide Nanoparticles Prepared by Precipitation from Solid State Solution
Autorzy:
Milkovič, O.
Gamcová, J.
Sopko, M.
Škorvánek, I.
Powiązania:
https://bibliotekanauki.pl/articles/1030258.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Df
Opis:
The influence of precipitation temperature on structural and magnetic properties of iron/iron-oxide nanoparticles is investigated. Nanoparticles were prepared by precipitation of γ-Fe precipitates in Cu-Fe solid solution and subsequently isolated by matrix dissolution. Precipitation annealing temperatures were 773, 873, and 973 K. Nanoparticles core-shell structure and morphology were characterized by X-ray diffraction, high-resolution transmission electron microscopy, and selected area electron diffraction. These measurements showed that average diameter of nanoparticles increases with precipitation temperature from 8.5 nm to 20.5 nm. The measurements of magnetization as a function of temperature and applied field have been performed by SQUID magnetometer in temperature range from 5 K to 200 K.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 747-749
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure characterization of noble metal-silica nanocomposites
Autorzy:
Zienkiewicz-Strzałka, M.
Pikus, S.
Powiązania:
https://bibliotekanauki.pl/articles/1075855.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Df
Opis:
The presence of highly dispersed metal particles on solid supports with well-defined microstructure is important in the field of functional materials, active catalysts as well as bionanomaterials for medical applications. Noble metal nanostructures, in particular silver, palladium, and platinum nanoparticles were formed from ammine complexes ([Pt(NH₃)₄]Cl₂, [Ag(NH₃)₂]OH, and [Pd(NH₃)₄]Cl₂) and supported on high ordered mesoporous silica (SBA-15) and aluminosilica matrix. In this work, the distribution, composition and crystal structure of supported noble metal nanoparticles were determined and characterized. Finally the stability of incorporated nanostructures was confirmed. The microstructures of the obtained samples were analyzed by high resolution transmission electron microscopy. Obtained results indicated that developed procedures of synthesis and modification of mesoporous ordered silica or their derivate by proposed nanostructures are effective and allow to obtain new nanocomposites and nanocatalysts in repeatable and controlled way.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 972-974
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Porous Silicon Based Sensor for Organic Vapors
Autorzy:
Kayahan, E.
Bahsi, Z.
Oral, A.
Sezer, M.
Powiązania:
https://bibliotekanauki.pl/articles/1193711.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.07.Df
Opis:
Porous silicon (PS) has been an attractive material for enhancing optical properties of silicon. Its large surface area for sensor applications and compatibility with silicon-based technologies has been a driving force for further technology development. In this study, ability of PS to sense at room temperature organic vapors such as acetone, trichloroethylene and hexane, which are harmful to human health, has been investigated. Electrical (DC) and photo-luminescence (PL) measurements in a controlled atmosphere (nitrogen gas and an organic vapor mix) were performed to test the sensor response towards the organic vapors. It was found that PS surface is very sensitive against these vapors. The experimental results also suggested that PS can be used as a new electro-optical material to sense harmful vapors.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1400-1402
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Porous Silicon Based Humidity Sensor
Autorzy:
Kayahan, E.
Powiązania:
https://bibliotekanauki.pl/articles/1401435.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.07.Df
Opis:
Porous silicon (PS) is well known as a photovoltaic material. However, in the last couple of years, research has focused on the use of porous silicon as chemical-biological sensors. This paper discusses the use of PS as an optical humidity sensor. Photo-luminescence (PL) quenching measurements in a controlled humidity atmosphere (mixed Nitrogen gas and water vapor) were performed to test the sensor response towards the water vapor. Surface morphologies of the PS samples were characterized by a scanning electron microscopy (SEM) and structural properties were investigated via Fourier Transform Infrared (FTIR) spectroscopy. It was found that PS surface is very sensitive to the water vapor. The experimental results suggested that PS surface is a promising candidate material to be used as a humidity sensor.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1397-1399
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Methanol Vapor Sensing by Porous Silicon
Autorzy:
Yılmaz, O.
Kayahan, E.
Gören, F.
Dumludağ, F.
Powiązania:
https://bibliotekanauki.pl/articles/1195231.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.07.Df
Opis:
In this study, methanol vapor sensing of porous silicon was investigated. The porous silicon samples were anodized in HF based solution and rinsed with ethanol or deionized water after the anodisation. Porous silicon surface is very sensitive for methanol vapor sensing and the sensitivity affect from the rinsing procedure of porous silicon. The experimental results show that porous silicon is a promising candidate material for sensing methanol vapor.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 288-289
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Water-Sorption Effects near Grain Boundaries in Modified MgO-Al₂O₃ Ceramics Tested with Positron-Positronium Trapping Algorithm
Autorzy:
Klym, H.
Ingram, A.
Shpotyuk, O.
Hadzaman, I.
Chalyy, D.
Powiązania:
https://bibliotekanauki.pl/articles/1030933.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Je
07.07.Df
Opis:
Water-sorption processes near grain boundaries in the MgO-Al₂O₃ ceramics prepared at different temperatures were studied using positron annihilation lifetime spectroscopy. Numerical values of three- and four-component treatment of spectra were used for study of physical- and chemical-sorption processes in the MgO-Al₂O₃ ceramics. To apply mathematical approach in the form of positron-positronium trapping algorithm into three-component treatment of positron annihilation lifetime spectra it was shown that physical-adsorbed water did not modify positron trapping sites near grain boundaries in water-immersed MgO-Al₂O₃ ceramics and localized mainly in nanopores. The chemically-adsorbed water modifies structural extended defects located near grain boundaries that accompanied them by void fragmentation at water desorption.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 864-868
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermoelectric properties of Ca₂Sn/Ca₃SnO
Autorzy:
Kalinowski, L.
Fijałkowski, M.
Goraus, J.
Powiązania:
https://bibliotekanauki.pl/articles/1047668.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Jf
66.70.Df
Opis:
We measured thermopower, thermal conductivity and electrical resitivity for Ca₂Sn sample across 4-350 K temperature range. Contrary to expectations from recent DFT based calculations the thermopower is not particularly large, reaching 7 μV at 350 K. The thermoelectric figure of merit renders this material in unmodified form practically unusable for thermoelectric aplications.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 384-386
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature Sensitive Spinel-Type Ceramics in Thick-Film Multilayer Performance for Environment Sensors
Autorzy:
Hadzaman, I.
Klym, H.
Shpotuyk, O.
Brunner, M.
Powiązania:
https://bibliotekanauki.pl/articles/1550632.pdf
Data publikacji:
2010-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Je
07.07.Df
Opis:
Temperature sensitive thick films based on spinel-type semiconducting ceramics of different chemical composition $Cu_{0.1}Ni_{0.1}Co_{1.6}Mn_{1.2}O_{4}$ (with $p^{+}$-types of electrical conductivity), $Cu_{0.1}Ni_{0.8}Co_{0.2}Mn_{1.9}O_{4}$ (with p-types of electrical conductivity) and their multilayer $p^{+}$-p structures were fabricated and studied. These thick-film elements possess good electrophysical characteristics before and after long-term ageing test at 170°C. It is shown that degradation processes connected with diffusion of metallic Ag into film grain boundaries occur in one-layer p- and $p^{+}$-conductive thick films. The $p^{+}$-p structures were of high stability, the relative electrical drift was not greater than 1%.
Źródło:
Acta Physica Polonica A; 2010, 117, 1; 234-237
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inverted Rib Waveguides - Theoretical Analysis of Sensing Properties
Autorzy:
Tyszkiewicz, C.
Powiązania:
https://bibliotekanauki.pl/articles/1399407.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.79.Gn
07.07.Df
Opis:
Optical waveguides are fundamental components of chemical and biochemical evanescent wave sensors. Presented work is devoted to theoretical investigations of homogeneous and surface sensitivity characteristics of the inverted rib waveguide structure. The inverted rib waveguide discussed in this paper is composed of an ion-exchange based channel waveguide formed in a glassy substrate and a uniform, high refractive index, sol-gel derived $SiO_2-TiO_2$ film. Characteristics of a homogeneous sensitivity, a surface sensitivity and fundamental modes sensitivity differences in function of a uniform film thickness and a maximal refractive index contrast of the gradient index channel waveguide are given. The influence of the $SiO_2-TiO_2$ film thickness on sensitivity characteristics is discussed. The analysis is carried out on a bases off the effective index method used with the transfer matrix method.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 582-585
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Free Space Optical Detection Module Operating at the Wavelength Range of 8-12 μm
Autorzy:
Gutowska, M.
Nowakowski, M.
Bielecki, Z.
Mikolajczyk, J.
Szabra, D.
Paliwoda, R.
Pedzinska, M.
Pawluczyk, J.
Gawron, W.
Powiązania:
https://bibliotekanauki.pl/articles/1506789.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.07.Df
85.60.Bt
Opis:
The paper presents the construction and test results of a long-term radiation detector module for free space optical communication operated at the wavelength range of 8-12 μm. In the module a Polish detector manufactured in the company Vigo System S.A. was applied. High sensitivity of the detection module was achieved through a multi-layered heterostructure HgCdTe with immersion lens, which is optimized for the radiation detection at the wavelength of 10 μm. Detector noises were reduced as a result of detector cooling by means of four-stage thermoelectric cooler. The developed detection module is dedicated to design a next-generation optical data link. The link will be characterized by a greater range in difficult weather conditions in relation to the currently offered links operating at the shorter wavelengths.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1143-1147
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optopneumatic Detector with Platinum Flow Sensor
Autorzy:
Jasek, K.
Budzyński, T.
Stryszak, E.
Powiązania:
https://bibliotekanauki.pl/articles/1796139.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.35.Iv
07.07.Df
Opis:
In optopneumatic detectors, operating on principle of the gaseous infrared detectors, the radiation absorbed in the gas is changed into pressure fluctuation, followed by periodic flow of the gas between detector chambers. This flow is usually measured by means of hot-wire or hot-film anemometers. Their parameters in a great measure determine the quality of the whole detector. The flow sensor used in optopneumatic detectors should have short time constant, high sensitivity, possibility to distinguish the flow direction, and high chemical resistance to the gas which the detector is filled with. To meet these requirements, micro-electro-mechanical system flowmeter consisting of two platinum hot films placed in series in the flow direction was made. Platinum film of 0.3 μm thickness was deposited by magnetron spattering on thin membrane, which was composed of polysilicon substrate (0.5 μm) and two $Si_{3}N_{4}$ layers with thickness of 0.1 μm. The obtained platinum elements have resistance of 32 Ω and temperature coefficient of resistance of 2.31× $10^{-3}$/°C. Hot film does not change its parameters up to 350°C, whereas typical working temperature of such films ranged from 150 to 200°C. Anemometer characteristics and voltage-current dependences were determined in this work. The linear range of operation from 0 to 10 ml/min and sensitivity suitable for optopneumatic detectors were found. The time constant of the flowmeter is equal to 11 ms (95% of final signal), that enables the detector to operate with frequency up to 100 Hz. The flowmeters were applied in detectors filled with sulphur dioxide and were tested for six months at temperature of hot-film about 150°C. During that time no changes of their parameters were observed.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 321-324
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hyper-Solitons in Nematic Liquid Crystals
Autorzy:
Strinic, A.
Petrović, M.
Belić, M.
Powiązania:
https://bibliotekanauki.pl/articles/1791208.pdf
Data publikacji:
2009-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Df
42.65.Tg
Opis:
We study laser light propagation in a cell containing a liquid crystal in the nematic phase. We launch hyper-Gaussian beams and follow their behavior within the cell, in time and in three spatial dimensions, utilizing an appropriately developed theoretical model and a numerical procedure based on the fast Fourier transform. We demonstrate the formation of stable "hyper-soliton" breathers in a narrow region of beam intensities, for fixed other parameters. Hyper-solitons are similar in appearance and behavior to the usual solitons, formed by launching the usual Gaussian beams; however noticeable differences persist.
Źródło:
Acta Physica Polonica A; 2009, 116, 4; 510-512
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In Situ Monitoring of Electroepitaxial Growth of Thick AlGaAs Layers
Autorzy:
Żytkiewicz, Z. R.
Powiązania:
https://bibliotekanauki.pl/articles/1929752.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.55.Df
81.10.Dn
Opis:
In situ growth monitoring technique has been used to analyse growth disturbances during the liquid phase electroepitaxial growth of thick AlGaAs layers. It allowed us to explain the nature of growth instability occurring at the end of the growth and affecting the maximum thickness of AlGaAs layers obtainable by liquid phase electroepitaxy.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 777-780
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Raman Scattering from Acoustic Phonons Confined in Spherical Nanoparticles
Autorzy:
Kostić, R.
Powiązania:
https://bibliotekanauki.pl/articles/1807815.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Df
63.22.-m
Opis:
Low-frequency Raman scattering from small spherical particles is analyzed. Frequencies of vibrational modes are calculated in elastic continuum approximation, which considers one nanoparticle as homogeneous elastic sphere. Parameters of this model are transverse $(v_T)$ and longitudinal $(v_L)$ sound velocities of material, i.e. elastic properties of bulk material. Frequencies of vibrational modes are scaled as function of mentioned bulk parameters for symmetric l=0 and quadrupolar l=2 spheroidal modes, in the case of stress-free boundary conditions. Calculated values are compared with the low-frequency Raman experimental results from literature (Ge, Si, CdS, CdSe, $CeO_2$, ...). These calculated relations can be practically used to examine nanoparticles of any bulk material. We presented also a procedure how to establish $v_L$ and $v_T$ of material from low-frequency Raman spectra and dimension d of particles.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 62-64
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Optical Measurements of Elastic Constants in Nematic Liquid Crystal
Autorzy:
Bajdecki, W. K.
Karpierz, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/2008272.pdf
Data publikacji:
1999-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.-k
42.70.Df
Opis:
A new method of measurements of elastic constants of nematic liquid crystals by applying the nonlinear optical effect is presented. This method bases on measurements of a value of the reorientation threshold in a liquid crystal layer while the reorientation is induced by the light beam passing through the layer. The obtained results are in a qualitative compatibility with the results obtained by classical methods.
Źródło:
Acta Physica Polonica A; 1999, 95, 5; 793-800
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reorientational Nonlinear Phenomena in Thin Nematic Liquid Crystals Layer
Autorzy:
Brzdąkiewicz, K.
Bajdecki, W. K.
Kozanecka, A.
Karpierz, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/2023855.pdf
Data publikacji:
2001-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.-k
42.70.Df
Opis:
In this paper the detailed study of the self-diffraction phenomena due to reorientational optical nonlinearity in nematic liquid crystalline cell is presented. The optical nonlinear effect is additionally modified by external low-frequency electric field. The dependence of nonlinear response on light polarization is also analyzed. The theoretical investigations are compared with experimental results and the theoretical predictions are in excellent agreement with experimental data.
Źródło:
Acta Physica Polonica A; 2001, 99, 1; 183-192
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electroepitaxial Growth of GaSb and AlGaSb Thick Epitaxial Layers
Autorzy:
Zytkiewicz, Z. R.
Dobosz, D.
Powiązania:
https://bibliotekanauki.pl/articles/1934052.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.55.Df
81.10.Dn
Opis:
Semi-bulk epitaxial layers of GaSb and AlGaSb up to 3 and 1 mm thick, respectively, were successfully grown by the liquid phase electroepitaxy on GaSb substrates. The growth procedure allowed us to achieve high crystallographic perfection as well as compositional uniformity of ternary layers.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 965-968
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial Optical Solitons in Bulk Nematic Liquid Crystals
Autorzy:
Assanto, G.
Peccianti, M.
Conti, C.
Powiązania:
https://bibliotekanauki.pl/articles/2035665.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Df
42.65.Tg
Opis:
We present an overview of our recent experimental results on two-dimensional optical spatial solitons in voltage biased planar cells with nematic liquid crystals. Excitation, induced waveguiding, and interactions are illustrated and interpreted in terms of the inherent re-orientational, non-resonant and nonlocal nonlinear response.
Źródło:
Acta Physica Polonica A; 2003, 103, 2-3; 161-167
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of Spatial Solitons in Twisted Nematics Waveguides
Autorzy:
Karpierz, M. A.
Brzdąkiewicz, K. A.
Nguyen, Q. V.
Powiązania:
https://bibliotekanauki.pl/articles/2035666.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.Wi
42.70.Df
Opis:
Theoretical analysis of light beam propagation in twisted nematic liquid crystalline waveguides is presented. Due to the optical reorientation nonlinearity, the light beam changes the direction of propagation and optical spatial soliton is formed. Modeling of such behavior is presented by using (2+1)-dimensional vector beam propagation method as well as simplified (1+1)-dimensional method. Although both approaches give similar results, the differences are discussed in detail.
Źródło:
Acta Physica Polonica A; 2003, 103, 2-3; 169-175
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamical Electro-Optical Characterization of Policryps Gratings
Autorzy:
Abbate, G.
Marino, A.
Vita, F.
Powiązania:
https://bibliotekanauki.pl/articles/2035667.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Df
42.79.Kr
Opis:
We have studied the dynamical response at 633 and 1550 nm of a new polymer-liquid crystal composite, realized in a form of a thick grating. This composite is known as Policryps, an acronym that stands for "Polymer Liquid Crystals Polymer Slides", because it shows a sequence of polymeric sheets alternated by layers containing only liquid crystal. Policryps gratings can be electrically switched between diffracting and non-diffracting states with a good diffraction efficiency in the visible region. After optimization of their performances, including response time, in the near infrared region, they can be conveniently proposed as a key component in photonic devices for telecom applications. Our results show very interesting response times ranging from 1 to 3 ms (switching on) and from 0.1 to 0.4 ms (switching off). Furthermore, switching ON times appear to be ruled by two different physical mechanisms with characteristic times differing by one order of magnitude. A deeper insight of these mechanisms might lead to response times, all in the submillisecond range.
Źródło:
Acta Physica Polonica A; 2003, 103, 2-3; 177-186
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Light Polarization on Reorientation Nonlinearity in Nematic Liquid Crystals
Autorzy:
Brzdąkiewicz, K. A.
Karpierz, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/2035686.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.-k
42.70.Df
Opis:
Nematic liquid crystals are characterized by a giant optical nonlinearity which has its origin in the molecular reorientational phenomenon. Uniqueness of this nonlinear mechanism causes that response of the medium is dependent on many conditions. Among various circumstances, both an initial alignment of liquid crystal cell and geometry of the system are very important, but in this paper a significant role of light polarization in nonlinear effects observed in nematics is emphasized. Additionally, it is underlined that dependence on light polarization does not have only trivial aspect of initial conditions. More complex seems to be the fact that due to the high optical anisotropy of the medium the state of light polarization is changing on the way of beam propagation. As a consequence, the modifications of molecular orientation in the liquid crystal cell are strongly dependent upon light polarization.
Źródło:
Acta Physica Polonica A; 2003, 103, 2-3; 195-205
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Discrete Space-Time by Means of the Weyl-Dirac Theory
Autorzy:
Agop, M.
Chicos, L.
Gîrţu, M.
Powiązania:
https://bibliotekanauki.pl/articles/2047353.pdf
Data publikacji:
2007-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
04.20.Cv
05.45.Df
Opis:
A connection between the Weyl-Dirac theory and scale relativity theory through the hydrodynamic models (relativistic and non-relativistic approaches) is established. In such conjecture, considering that the motions of the microparticles take place on continuous but non-differentiable curves i.e. on fractals, a Weyl-Dirac type equation was found. Some correspondences with known hydrodynamic models, particularly Białynicki-Birula's approach, are analyzed. All these results reflect the fractal structure of the space-time (a concept in agreement with the new ideas on the space-time)
Źródło:
Acta Physica Polonica A; 2007, 112, 1; 3-12
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nodal Domains in Chaotic Microwave Rough Billiards with and without Ray-Splitting Properties
Autorzy:
Hul, O.
Savytskyy, N.
Tymoshchuk, O.
Bauch, S.
Sirko, L.
Powiązania:
https://bibliotekanauki.pl/articles/2044609.pdf
Data publikacji:
2006-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Mt
05.45.Df
Opis:
We study experimentally nodal domains of wave functions (electric field distributions) lying in the regime of Breit-Wigner ergodicity in the chaotic microwave half-circular ray-splitting rough billiard. Using the rough billiard without ray-splitting properties we also study the wave functions lying in the regime of Shnirelman ergodicity. The wave functions Ψ$\text{}_{N}$ of the ray-splitting billiard were measured up to the level number N=204. In the case of the rough billiard without ray-splitting properties, the wave functions were measured up to N=435. We show that in the regime of Breit-Wigner ergodicity most of wave functions are delocalized in the n, l basis. In the regime of Shnirelman ergodicity wave functions are homogeneously distributed over the whole energy surface. For such wave functions, lying both in the regimes of Breit-Wigner and Shnirelman ergodicity, the dependence of the number of nodal domains Ɲ$\text{}_{N}$ on the level number N was found. We show that in the regimes of Breit-Wigner and Shnirelman ergodicity least squares fits of the experimental data reveal the numbers of nodal domains that in the asymptotic limit N→∞ coincide within the error limits with the theoretical predictionƝ$\text{}_{N}$/N≃ 0.062. Finally, we demonstrate that the signed area distribution Σ$\text{}_{A}$ can be used as a useful criterion of quantum chaos.
Źródło:
Acta Physica Polonica A; 2006, 109, 1; 73-87
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of External Electric Field on Time of Nonlinear Optical Reorientational Effect in Nematics
Autorzy:
Bajdecki, W. K.
Karpierz, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/2035684.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.-k
42.70.Df
Opis:
Nonlinear reorientation phenomena in nematic liquid crystals cause extremely large refractive index changes. However, this effect is relatively slow and the determination of the time necessary to appearing or disappearing of the nonlinear effect is an important issue. In this work we present measurements of the time of increasing the nematics reorientation induced by the light beam passing through the liquid crystalline layer. The influence of external low-frequency electric field suppressing reorientation is also reported. The obtained results describing relations between time and optical power of light as well as between time and external electric field intensity are in good agreement with theory.
Źródło:
Acta Physica Polonica A; 2003, 103, 2-3; 187-193
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the High Compositional Uniformity of Thick GaAlAs Layers Grown by Liquid Phase Electroepitaxy
Autorzy:
Żytkiewicz, Z. R.
Miotkowska, S.
Powiązania:
https://bibliotekanauki.pl/articles/1923664.pdf
Data publikacji:
1992-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.55.Df
81.10.Dn
Opis:
The results of electroepitaxial growth of thick GaAlAs layers on GaAs substrates are presented. It is experimentally proven that effective convective mixing of the solution volume results in the compositional uniformity of GaAlAs layers, even in spite of the high compositional non-uniformity of the material supplying the solutes (Al, As) to the solution during the growth of the layers. For the first time this allowed us to grow uniform GaAlAs layers with thicknesses up to 200-300 μm in a wide composition range from a small (5 g) amount of solution.
Źródło:
Acta Physica Polonica A; 1992, 82, 5; 765-768
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Nonlinearity in Liquid Crystalline Optical Waveguides
Autorzy:
Karpierz, M. A.
Domański, A. W.
Sierakowski, M.
Świłło, M.
Woliński, T. R.
Powiązania:
https://bibliotekanauki.pl/articles/2008217.pdf
Data publikacji:
1999-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.Wi
42.70.Df
Opis:
The analysis of optical orientational nonlinearity in nematic liquid crystalline planar waveguides is presented. The analyzed nonlinearity leads to unique properties that are not observed in other types of nonlinear waveguides. Theoretical results are confirmed by experimental data obtained in liquid crystalline directional couplers and in the self-focusing effect observed in the planar liquid crystalline waveguides.
Źródło:
Acta Physica Polonica A; 1999, 95, 5; 783-792
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Properties of Waveguides with Twisted Nematic Liquid Crystal
Autorzy:
Karpierz, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/2015119.pdf
Data publikacji:
2001-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.Wi
42.70.Df
Opis:
Optical reorientational nonlinearity in twisted nematic liquid crystalline planar waveguide is analyzed theoretically. It is shown that optical nonlinearity for guided modes in analyzed waveguides can be approximated by saturation nonlinearity. Predicted nonlinearity is large enough to observe effects like spatial solitons formation with milliwatts of light power.
Źródło:
Acta Physica Polonica A; 2001, 99, 1; 161-173
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trend Detection in Climate Change Indicators Using Non-Parametric Statistics: A Case Study of Abu Dhabi, United Arab Emirates
Autorzy:
Basarir, A.
Arman, H.
Hussein, S.
Murad, A.
Aldahan, A.
Abdulla Al-Abri, M.
Powiązania:
https://bibliotekanauki.pl/articles/1031779.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
92.70.Kb
92.05.Df
Opis:
This study focuses on detecting trends for climate change indicators, such as average monthly temperature, rainfall, humidity, and wind speed for fourteen stations located between Al Ain and Abu Dhabi cities of the United Arab Emirates. Mann-Kendall non-parametric test was run on monthly time series data for the period 2003-2015 with consideration of seasonality. Significant increasing/decreasing trends in rainfall (for four stations), humidity (for six stations), and wind speed (for nine stations) were detected while no significant trend was observed in temperature for all stations.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 655-657
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Fluxgate Sensor Characteristics Modeling Using Extended Preisach Model
Autorzy:
Frydrych, P.
Szewczyk, R.
Salach, J.
Powiązania:
https://bibliotekanauki.pl/articles/1199497.pdf
Data publikacji:
2014-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.60.-d
07.07.Df
Opis:
This paper presents the implementation of the extended Preisach model for fluxgate sensor characteristics modeling. The developed model enables the optimization of fluxgate sensor parameters for a given core material. Model consists of two parts. The first one describes magnetic characteristics of the core, while the second part calculates output signal according to sensor dimensions and electric circuit parameters. The model is easy to adapt for modeling of other devices with magnetic cores. It can be used instead of costly and time consuming prototype testing.
Źródło:
Acta Physica Polonica A; 2014, 126, 1; 18-19
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the Responses of Metal-Oxide Semiconductor Nanostructures to Nitrogen Dioxide
Autorzy:
Procek, M.
Pustelny, T.
Powiązania:
https://bibliotekanauki.pl/articles/1399393.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
82.47.Rs
07.07.Df
Opis:
The paper concerns analyses of the nanostructures based on metal-oxide semiconductors, such as titanium dioxide $(TiO_2)$ and zinc oxide $(ZnO)$ exposed to nitrogen dioxide $(NO_2)$ in an atmosphere of dry and humid synthetic air. The investigations were performed at a rather low temperature amounting to 120°C. The responses of sensors differing in the morphology of their structures have been compared. Also the time of their responses were compared with each other. The paper describes theoretically changes in the effective resistance of these structures due to the interaction of the gas. The presented results are being discussed based on the analysis of physical and chemical phenomena.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 529-533
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MMI Structures Covered by Bromocresol Purple for Ammonia Detection
Autorzy:
Szewczuk, A.
Błahut, M.
Powiązania:
https://bibliotekanauki.pl/articles/1399404.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.79.Gn
07.07.Df
Opis:
In the paper examinations of a lightguide sensor on the base of gradient index multimode interference structures are presented. Investigated structures were fabricated in potassium-sodium ion exchange process. Multimode interference sensor was designed for ammonia detection. Bromocresol purple covering the multimode section was used as a sensing layer. Numerical calculations were performed with the use of modal analysis and beam propagation method to optimise sensor geometry and sensing layer thickness. Experimental results show the possibility of ammonia detection from the concentration of tens ppm.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 570-573
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pattern Recognition Applied to Analysis of Gas Sensors Array Data
Autorzy:
Marczyński, P.
Szpakowski, A.
Tyszkiewicz, C.
Pustelny, T.
Powiązania:
https://bibliotekanauki.pl/articles/1418023.pdf
Data publikacji:
2012-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.50.Sk
07.07.Df
Opis:
For an array of eight chemoresistive gas sensors a computer pattern recognition system was built. Multivariate data analysis was performed for measurements of three gases' dilutions: hydrogen $(H_2)$, methane $(CH_4)$, and carbon monoxide $(CO)$. The pattern recognition system included a feature subset selection algorithm involving PCA and objective function. Dimensionality reduction was applied to two kinds of patterns: three aforementioned gases and six different concentrations of hydrogen. For patterns of the three gases, classification tests were performed using k-NN algorithm and N-fold based validation method.
Źródło:
Acta Physica Polonica A; 2012, 122, 5; 847-849
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensing Properties of Four-Layered Planar Waveguides - Theoretical Analysis
Autorzy:
Tyszkiewicz, C.
Powiązania:
https://bibliotekanauki.pl/articles/1418062.pdf
Data publikacji:
2012-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.79.Gn
07.07.Df
Opis:
Optical waveguides are the fundamental components of chemical and biochemical evanescent wave sensors. Presented work focuses on the theoretical investigations of homogeneous sensitivity of four-layered composite planar waveguide composed of a silica-titania film and a titania film deposited on a glassy substrate in order of citing. Characteristics of a homogeneous sensitivity and a fundamental modes homogeneous sensitivity difference of such a structure are compared with the ones for a three-layered waveguide composed of silica-titania waveguiding film. Therefore the influence of a high refractive index titania film on homogeneous sensitivity characteristics of three-layered structure is given. It was shown that homogeneous sensitivity difference of fundamental modes of four-layered waveguide can be optimized with respect to thicknesses of each layer. For each value of a cover refractive index there exists the minimal thickness of the titania layer which maximizes the homogeneous sensitivity difference of fundamental modes.
Źródło:
Acta Physica Polonica A; 2012, 122, 5; 908-914
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Refractive Indices, Order Parameter and Optical Transmittance Studies of a Nematic Liquid Crystal Mixture
Autorzy:
Singh, A. K.
Manohar, R.
Shukla, J. P.
Biradar, A. M.
Powiązania:
https://bibliotekanauki.pl/articles/2047089.pdf
Data publikacji:
2006-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.30.-v
42.70.Df
Opis:
Measurements of ordinary refractive index, birefringence, density, and order parameter were made on a technologically important nematogen and the data obtained for its nematic and isotropic phase were reported. A modified wedge method was used for the measurement of the birefringence (δ n). The nematic-isotropic phase transition temperature matches very well as is exhibited from the value of refractive indices and densities obtained using different techniques. The optical anisotropy and density data were used to determine the order parameter and principal polarizability of the nematic mixture using the Vuks approach and their temperature dependence was discussed. The macroscopic order parameter was obtained and compared with microscopic order parameter. These two values agree very well.
Źródło:
Acta Physica Polonica A; 2006, 110, 4; 485-493
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Inelastic Light Scattering in a Smectic Liquid Crystal
Autorzy:
Pura, B.
Jęda, W.
Zagórski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1968843.pdf
Data publikacji:
1998-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.df
42.65.-k
Opis:
Results of measurements of the intensity of light scattered by a smectic liquid crystal are reported for three phases of the specimen. A strong dependence of the scattered intensity on the relative directions of polarization vector and molecular orientation is observed. A mechanism of light interaction with material is proposed, it is attributed to brillouin - like scattering of light on director - system excitations.
Źródło:
Acta Physica Polonica A; 1998, 93, 3; 465-470
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multivariate Analysis in Gas Sensing Applications
Autorzy:
Szpakowski, A.
Tyszkiewicz, C.
Pustelny, T.
Powiązania:
https://bibliotekanauki.pl/articles/1811555.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.50.Sk
07.07.Df
Opis:
In gas sensing applications we often use sensors which have poor selectivity. Such sensors are mature, cheap devices with simple application circuits. Unfortunately, their cross sensitivity greatly restricts their usefulness when used in systems which employs univariate analysis. One method which allows to overcome this difficulty is utilization of multivariate analysis methods applied to the response from the group of such non-selective sensors. This work presents the multivariate, pattern recognition system utilized to process the response of an array of non-selective semiconductor sensors to obtain the qualitative information.
Źródło:
Acta Physica Polonica A; 2008, 114, 6A; A-239-A-242
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Roughness Method to Estimate Fractal Dimension
Autorzy:
Błachowski, A.
Ruebenbauer, K.
Powiązania:
https://bibliotekanauki.pl/articles/1808085.pdf
Data publikacji:
2009-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Df
61.43.Hv
Opis:
A method based on the pattern roughness was introduced for determination of the fractal dimension and tested for fractals like the Sierpiński carpet, the Sierpiński triangle, standard Cantor set, the Menger sponge and the Sierpiński tetrahedron. It was tested for non-fractal pattern like two- and four-dimensional gray scale random dust as well. It was found that for all these patterns the Hausdorff dimension is reproduced with relatively high accuracy. Roughness method is based on simple, fast and easy to implement algorithm applicable in any topological dimension. It is particularly suited for patterns being composed of the hierarchy of structures having the same topological dimension as the space embedding them. It is applicable to "fuzzy" patterns with overlapping structures, where other methods are useless. It is designed for pixelized structures, the latter structures resulting as typical experimental data sets.
Źródło:
Acta Physica Polonica A; 2009, 115, 3; 636-640
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication and Characterization of Hybrid Tunnel Magnetoresistance Structures with Embedded Self-Assembled Nanoparticle Templates
Autorzy:
Siffalovic, P.
Majkova, E.
Chitu, L.
Halahovets, Y.
Jergel, M.
Senderak, R.
Luby, S.
Weis, M.
Satka, A.
Szymański, B.
Stobiecki, F.
Timmann, A.
Roth, S.
Powiązania:
https://bibliotekanauki.pl/articles/1810565.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.cf
61.46.Df
Opis:
We report on an incorporation of self-assembled templates of superparamagnetic Fe-O nanoparticles into tunnel magnetoresistance devices. We fabricated a multilayer stack composed of the following layer sequence: Cr/Au/Co/NP/Co/Cu on Si(100) substrate where NP stands for a self-assembled layer of nanoparticles deposited by the Langmuir-Blodgett technique. The X-ray reflectivity and grazing-incidence small angle X-ray scattering were employed to study the layers thicknesses and interface morphology in each preparation step. In particular, the grazing-incidence small angle X-ray scattering was measured before and after the nanoparticle incorporation as well as on the complete tunnel magnetoresistance stack. In this way, in-depth morphology profile during subsequent preparation steps was obtained. We demonstrate that X-ray analysis of the deposited tunnel magnetoresistance stack is essential for successful fabrication of novel hybrid devices consisting of self-assembled nanoparticles.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 332-335
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Supervising water quality of water resources via telemetric system
Autorzy:
Üncü, İ.
Akdurul, M.
Powiązania:
https://bibliotekanauki.pl/articles/1061570.pdf
Data publikacji:
2016-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
06.20.Dk
07.07.Df
07.88.+y
Opis:
Urban water resources are some of the main places where microorganisms can reproduce and where people can get easily infected. For these reasons, pools must be sterilized continuously. This can only be done if the water quality of the pool is in accordance with the standards of the Ministry of Forestry and Water Affairs. Monitoring water quality in real-time gives an instant response opportunity. With the software prepared using the. Net architecture, real-time temperature, pH, and chlorine content values of a pool were transferred to a database. Swimming pool water quality was then evaluated and compared with the Ministry of Forestry and Water Affairs standards via the expert system technique, which is one of the artificial intelligence technologies. In this study, results of instant evaluation of the water quality made for water resources via telemetric systems, are reported. Additionally, a remotely-controlled dosing operation was performed.
Źródło:
Acta Physica Polonica A; 2016, 130, 1; 293-296
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some Aspects Concerning the "Memorization Effect" in Complex Fluid
Autorzy:
Agop, M.
Ochiuz, L.
Timofte, D.
Barlescu, V.
Danila, M.
Gheorghita, L.
Paun, V.
Solovastru, L.
Popa, C.
Powiązania:
https://bibliotekanauki.pl/articles/1204873.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Df
47.53.+n
03.65.-w
Opis:
In the frame of a non-standard scale relativity model, the specific momentum, states density and internal energy conservations laws are obtained. The chaoticity, either through turbulence in the fractal hydrodynamics approach, or through stochasticization in the Schrödinger type approach, is generated only by the non-differentiability of the movement trajectories of the complex fluid entities. Using the conservation laws mentioned above, by numerical simulations, hysteretic type effects (dynamics of hysteretic cycles) occur.
Źródło:
Acta Physica Polonica A; 2014, 126, 3; 663-669
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Nanoparticle Geometry and Temperature on the Structural Evolution in FeCo Nanoalloys
Autorzy:
Yalçin, M.
Mekhrabov, A.
Akdeniz, M.
Powiązania:
https://bibliotekanauki.pl/articles/1293521.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.43.Bn
61.46.Df
61.46.-w
Opis:
Effects of nanoparticle size (2.0-6.0 nm) and shape (spherical and cubic) on structural characteristic of atomic ordering processes and order-disorder transformation in B2-type ordered equiatomic-FeCo nanoalloys have been studied by combining electronic theory of alloys in the pseudopotential approximation with Ising-type Hamiltonian site exchange Monte Carlo simulation method. Structural evolutions in amorphous nanoparticles (2-6 nm) of $Fe_{50}Co_{50}$ alloy have been utilized via molecular dynamic simulations from room temperatures to 1700 K temperatures. It has been shown that disordering starts at surface and propagates into volume of nanoparticles with increasing temperature. FeCo nanoparticles with critical dimensions more than 5 nm have order-disorder transformation behavior almost similar with bulk B2-FeCo alloys irrespective of their shape. Molecular dynamic analyses indicate that short- and medium-range ordered atomic structures exist in quenched $Fe_{50}Co_{50}$ nanoparticles at room temperature. Deformed bcc structures and deformed icosahedron structures are most probable atomic configurations for 2, 4, 6 nm particles of $Fe_{50}Co_{50}$ nanoalloy.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 600-602
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Annealing Temperature on $Y_2O_3:SiO_2$ Nanocomposite Prepared by Sol-Gel Process
Autorzy:
Ahlawat, R.
Aghamkar, P.
Powiązania:
https://bibliotekanauki.pl/articles/1205213.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Bc
61.46.Df
78.67.Bf
Opis:
Oxide nanoparticles embedded in a polymer matrix produce nanocomposites which are useful for optics and electronic applications. Yttrium oxide nanoparticles have received much attention due to their various properties and are significantly used in fundamental and application oriented fields. The present paper reports the influence of annealing temperature on the $Y_2O_3:SiO_2$ nanocomposite prepared by sol-gel process. $Y(NO_3)_3 ·4H_2O$ and tetraethoxysilane were used as precursors and obtained powdered form of $Y_2O_3:SiO_2$ composite. The powder sample was annealed at 500C and 900C for 6 h which were characterized by X-ray diffraction, Fourier transform infrared and transmission electron microscope. X-ray diffraction data described that the broadening of peaks decreases with increase in annealing temperature which may be due to the increase in particle size. Sample analyzed by Fourier transform infrared and transmission electron microscopy confirmed the grain size dependence on annealing temperature. Cubic phase of yttrium oxide crystal structure was obtained within the silica matrix. The nanocrystallites size has been calculated using Debye-Scherrer formula, Williamson-Hall plot and transmission electron micrographs and compared at two different temperatures (a) 500C and (b) 900C.
Źródło:
Acta Physica Polonica A; 2014, 126, 3; 736-739
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method of Measuring the Distance to an Object Based on One Shot Obtained from a Motionless Camera with a Fixed-Focus Lens
Autorzy:
Murawski, K.
Powiązania:
https://bibliotekanauki.pl/articles/1189717.pdf
Data publikacji:
2015-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
06.30.Bp
07.05.Pj
07.07.Df
Opis:
The paper presents the method of measuring the distance to the object based on digital image processing. The solution is characterized in that the distance measurement to the object is performed by a motionless camera with established and unchanged parameters during measurement. The camera is equipped with a one non-stereoscopic lens. The measured distance is determined on the basis of one view of an object presented on one image. The image is made at a constant and invariant setting of the optical path such as: focus, aperture and focal length.
Źródło:
Acta Physica Polonica A; 2015, 127, 6; 1591-1595
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reconstruction of Lost Fragments of Signal Received from the Wireless Sensor Measuring Fluid Pressure inside the Eye Ball
Autorzy:
Murawski, K.
Grad, L.
Rękas, M.
Powiązania:
https://bibliotekanauki.pl/articles/1189729.pdf
Data publikacji:
2015-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.07.Df
88.80.ht
87.85.Ng
Opis:
The aim of the paper is to present a technique of reconstructing data received from a wireless sensor for measuring intraocular pressure. The algorithm was developed to automatically regenerate samples lost due to fortuitous events in clinical trials. The test consisted in measuring the pressure within 24 h, during which the intraocular pressure curve were determined. The paper also discusses the structure and the physical basis of sensor operation and shows the advantages resulting from its use.
Źródło:
Acta Physica Polonica A; 2015, 127, 6; 1596-1600
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Accuracy Analysis of the Box-Counting Algorithm
Autorzy:
Górski, A.
Drożdż, S.
Mokrzycka, A.
Pawlik, J.
Powiązania:
https://bibliotekanauki.pl/articles/1408964.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Df
02.60.Gf
47.52.+j
Opis:
Accuracy of the box-counting algorithm for numerical computation of the fractal exponents is investigated. To this end several sample mathematical fractal sets are analyzed. It is shown that the standard deviation obtained for the fit of the fractal scaling in the log-log plot strongly underestimates the actual error. The real computational error was found to have power scaling with respect to the number of data points in the sample $(n_{tot})$. For fractals embedded in two-dimensional space the error is larger than for those embedded in one-dimensional space. For fractal functions the error is even larger. Obtained formula can give more realistic estimates for the computed generalized fractal exponents' accuracy.
Źródło:
Acta Physica Polonica A; 2012, 121, 2B; B-28-B-30
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Humidity on the Resistance Structures with Graphene Sensor Layer
Autorzy:
Pustelny, T.
Setkiewicz, M.
Drewniak, S.
Maciak, E.
Stolarczyk, A.
Procek, M.
Urbańczyk, M.
Gut, K.
Opilski, Z.
Pasternak, I.
Strupinski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1418032.pdf
Data publikacji:
2012-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.07.Df
42.81.Pa
82.47.Rs
Opis:
In the paper the results of investigations are presented concerning the influence of humidity of air on the resistance of a gas sensor structure with a graphene layer. The affects of nitrogen dioxide and humidity action on graphene were studied. We indicated that humidity might play an important role in determining the gas sensing properties of the graphene layer. In the paper it has been shown that in the case of a nitrogen oxide sensor, the reaction of $NO_2$ with water vapour can generate permanent defects in graphene.
Źródło:
Acta Physica Polonica A; 2012, 122, 5; 870-873
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensitive Films for Optical Detection of Ammonia and Nitrogen Dioxide
Autorzy:
Tyszkiewicz, C.
Karasiński, P.
Rogoziński, R.
Powiązania:
https://bibliotekanauki.pl/articles/1418064.pdf
Data publikacji:
2012-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Fw
42.70.Ce
07.07.Df
Opis:
The sol-gel technology allows preparation of the thin silica films ranging in porosity from dense to highly porous. These films can function as matrix binding molecules of pH-sensitive indicators and can be utilized as sensitive coatings for intensity based planar evanescent wave chemical sensors. This paper is devoted to manufacturing technology and characterization of highly porous silica films deposited on soda-lime glass substrates, impregnated with bromocresole purple and cresole red. Two different methods of impregnation were used: dip coating, which entails sensitization of both silica films deposited on each side of a substrate and selective deposition of a dye solution on single side of the substrate. Manufactured sensitive films were tested toward influence of gaseous ammonia and nitrogen dioxide on their spectral characteristics of the absorption coefficient and the imaginary part of the refractive index. It was shown that bromocresole purple allows detection of both gases: $NH_3$ and $NO_2$.
Źródło:
Acta Physica Polonica A; 2012, 122, 5; 915-920
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
World Financial 2014-2016 Market Bubbles: Oil Negative - US Dollar Positive
Autorzy:
Wątorek, M.
Drożdż, S.
Oświęcimka, P.
Powiązania:
https://bibliotekanauki.pl/articles/1398840.pdf
Data publikacji:
2016-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.Ht
89.65.Gh
05.45.Df
Opis:
Based on the log-periodic power law methodology, with the universal preferred scaling factor λ ≈2, the negative bubble on the oil market in 2014-2016 has been detected. Over the same period a positive bubble on the so-called commodity currencies expressed in terms of the US dollar appears to take place with the oscillation pattern which largely is mirror reflected relative to oil price oscillation pattern. It documents recent strong anticorrelation between the dynamics of the oil price and of the USD. A related forecast made at the time of FENS 2015 conference (beginning of November) turned out to be quite satisfactory. These findings provide also further indication that such a log-periodically accelerating down-trend signals termination of the corresponding decreases.
Źródło:
Acta Physica Polonica A; 2016, 129, 5; 932-936
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations of SAW Structures with Oxide Graphene Layer to Detection of Selected Gases
Autorzy:
Drewniak, S.
Pustelny, T.
Setkiewicz, M.
Maciak, E.
Urbańczyk, M.
Procek, M.
Opilski, Z.
Jagiello, J.
Lipinska, L.
Powiązania:
https://bibliotekanauki.pl/articles/1399339.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.81.Pa
82.47.Rs
07.07.Df
Opis:
In this paper we present the results of investigations of graphene oxide layers using the SAW structure (structure with surface acoustic wave propagated) exposed to the affect of low concentrations of hydrogen and nitrogen dioxide in synthetic air. During the measurements, the differential signal (from two measuring channels) was recorded. The sensing graphene oxide layer was deposited only on first channel, whereas the second channel was not covered by any additional layer. The tests were made with various concentrations of the analyzed gases and at various temperatures of the sensing structure during the measurements. Analyses were performed with special emphasis on the time response of the sensor structure to changes in the gas atmosphere.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 402-405
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of pH Value on the Growth and Structural Properties of Sol-Gel Synthesized Nanostructured ZnO
Autorzy:
Gültekin, D.
Alaf, M.
Akbulut, H.
Powiązania:
https://bibliotekanauki.pl/articles/1399831.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Df
81.07.Wx
81.20.Fw
Opis:
The aim of the research presented is to investigate the effect of pH value on the structural and morphological properties of nanostructured ZnO products. Zinc acetate dihydrate $(Zn(CH_3COO)_2·2H_2O)$ has been used as precursor whereas distilled water is used as a solvent. The pH value of the sol was adjusted with monoethanolamine (MEA) and it changed from acid to base in nature. X-ray diffractometer has been used to determine preferred crystal orientation and particle size of the thin films. Film morphologies have been examined by using JEOL JSM 6060 LV scanning electron microscope equipped with energy-dispersive spectroscopy.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 330-332
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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