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Wyszukujesz frazę "61.43.Gt" wg kryterium: Temat


Tytuł:
ZnO Nanopowders by a Microwave Hydrothermal Method - Influence of the Precursor Type on Grain Sizes
Autorzy:
Wolska, E.
Witkowski, B. S.
Godlewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/2048108.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.-n
61.43.Gt
81.07.Wx
78.55.Et
Opis:
Two series of ZnO nanopowders obtained by a microwave hydrothermal method are examined. We used two different zinc precursors (zinc chloride (ZnCl$\text{}_{2}$) and zinc nitrate hexahydrate (N$\text{}_{2}$O$\text{}_{6}$Zn·6H$\text{}_{2}$O)). Both types of nanopowders show a bright emission in a visible light, including the band edge emission, which indicates their good crystallographic quality. Results of scanning electron microscopy, photo- and cathodoluminescence investigations are presented.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 683-685
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Novel Molding Method and Enhanced Cell Homogeneity in the Powder Metallurgical Route for Production of Closed Cell Al-Foam
Autorzy:
Erturk, A.
Sahin, T.
Powiązania:
https://bibliotekanauki.pl/articles/1033369.pdf
Data publikacji:
2017-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Rm
82.33.Ln
61.43.Gt
61.05.cp
68.37.Hk
Opis:
TiH₂ content, mixing, pressing, different mold filling rate as the factors which affect foaming process on the powder metallurgical route were investigated. TiH₂ was added in the amount of 0.5-1-1.5-2 wt% to adjust the proper amount. Differential scanning calorimetry tests were conducted on the TiH₂ powders in order to obtain optimum hydrogen releasing condition. Aluminum and TiH₂ powders were blended with the different speed-time combination. The mix was compacted at different pressures with the aim of explaining of the oxide layer deformation. An acceptance-rejection criterion was developed and used in pore analysis. Also, the using of a borosilicate glass molding technique are completely original and a new approach.
Źródło:
Acta Physica Polonica A; 2017, 131, 1; 39-42
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on the Crystallization Process of Eu$\text{}^{3+}$:CaSiO$\text{}_{3}$ Gel Using Optical and Thermal Methods
Autorzy:
Andrić, Ž.
Krsmanović, R.
Marinović-Cincović, M.
Dramićanin, T.
Šećerov, B.
Dramićanin, M. D.
Powiązania:
https://bibliotekanauki.pl/articles/2047860.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.43.Gt
61.46.Hk
68.37.Hk
78.67.Bf
81.70.Pg
Opis:
Alkoxy sol-gel technique is an important preparation method for production of rare-earth based phosphors. Crystallization of gel provides a way to prepare phosphors on lower working temperatures than those required for the solid state reactions. CaSiO$\text{}_{3}$ gel samples were obtained through hydrolysis-condensation reactions of tetraethylorthosilicate as silica source. In this work we studied the process of crystallization of Eu$\text{}^{3+}$-activated CaSiO$\text{}_{3}$ gel and decomposition of organic precursors by means of thermal analysis and infrared spectroscopy. Results of scanning electron microscopy and energy-dispersion spectrometry are used to check chemical composition and morphology of synthesized material. Emission spectra and emission lifetime measurements are performed to investigate luminescence properties of Eu$\text{}^{3+}$ doped CaSiO$\text{}_{3}$ powder.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 969-974
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical and Thermal Investigation of Sol-Gel Derived Eu$\text{}^{3+}$:Y$\text{}_{2}$SiO$\text{}_{5}$ Nanoparticles
Autorzy:
Krsmanović, R.
Andrić, Ž.
Marinović-Cincović, M.
Zeković, I.
Dramićanin, M. D.
Powiązania:
https://bibliotekanauki.pl/articles/2047861.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.43.Gt
61.46.Hk
68.37.Hk
78.67.Bf
81.70.Pg
Opis:
Investigation done on Y$\text{}_{2}$SiO$\text{}_{5}$ nanoparticles doped with Eu$\text{}^{3+}$ ions obtained with the alkoxy sol-gel route is presented in this paper. We investigate the optical and thermal properties of obtained material during the conversion of the gel into nanocrystalline form. Fourier transform infrared spectroscopy and fluorescence spectroscopy of Eu$\text{}^{3+}$ ions are used for the optical characterizations, while thermal analysis is done with thermogravimetric-differential thermal analysis technique. Material exhibits characteristic luminescence emission of the trivalent europium ion.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 975-980
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of the Diffused Reflectance and Microstructure for the Phase Transformation of $KNO_{3}$
Autorzy:
Hafez, M.
Yahia, I.
Taha, S.
Powiązania:
https://bibliotekanauki.pl/articles/1398861.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.cp
64.60.-i
61.43.Gt
78.20.-e
72.15.Eb
Opis:
Optical, micro-structural, thermal and electrical properties of the investigated potassium nitrate ($KNO_{3}$) samples were characterized by various techniques such as X-ray analysis, scanning electron microscopy, UV-VIS-NIR absorption and differential scanning calorimetry. The presence of structural phase transition is checked by differential scanning calorimetry, electrical and X-ray analysis measurement. The thermal energy required for such transformation is calculated and found to be 46.2 J/g. The activation energies of the electrical conduction for $KNO_{3}$ were found to be 0.236 eV for phase II and 0.967 eV for phase I. The optical band gaps of $KNO_{3}$ for the higher photon energy are calculated and equal to 5.03 and 5.01 eV for II and I phases, respectively and at lower photon energy, the values are equal to 3.84 and 3.80 eV for II and I phases, respectively. The data which leads to the interpretation of electronic spectra of potassium nitrate is possible to assume that the long wavelength part of absorption band corresponds to n-π* transition. Then, the short-wavelength part is probably due to the transition in a higher excited state of symmetry π-π*. The mean values of crystalline sizes are determined by scanning electron microscopy analysis. Such information can considerably aid in understanding the process of transformations near the phase crystal modifications at 129°C.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 734-740
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Porous Silicon Formation by Metal-Assisted Chemical Etching
Autorzy:
Lipinski, M.
Cichoszewski, J.
Socha, R.
Piotrowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1807542.pdf
Data publikacji:
2009-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.16.Rf
81.05.Rm
78.55.Mb
61.43.Gt
78.67.Bf
Opis:
The method of metal-assisted chemical etching produces a porous silicon layer. Palladium particles are deposited on both: multi-crystalline and Czochralski grown mono-crystalline Si wafers by immersing them in $PdCl_{2}$ solution for 1 to 3 min. X-ray photoelectron spectroscopy analysis of Pd clusters shows a decrease in Pd metal fraction by prolonged immersion time t from $F_{Pd}$ = 71.2% for t = 1 min to $F_{Pd}$ = 61.4% for t = 3 min due to Pd oxidation process. Porous silicon forms by metal-assisted chemical etching in a HF:$H_{2}O_{2}$ solution for 1 to 3 min. Photoluminescence of metal-assisted chemical etched samples exhibits the peak with a maximum of t at λ=650 nm independent of the etching time. Simultaneously, the intensity of the photoluminescence spectra strongly decreases for extended etching time t = 3 min. This behavior is attributed to increasing layer macroporosity, which strongly reduces amount of light emitting nanocrystallites.
Źródło:
Acta Physica Polonica A; 2009, 116, S; S-117-S-119
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Genetic Algorithm for Extraction of the Parameters from Powder EPR Spectra
Autorzy:
Spałek, T.
Pietrzyk, P.
Sojka, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2043399.pdf
Data publikacji:
2005-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
02.60.Pn
02.60.Ed
76.30.Fc
82.75.Mj
61.43.Gt
Opis:
The application of the stochastic genetic algorithm in tandem with the deterministic Powell method to automated extraction of the magnetic parameters from powder EPR spectra was described. The efficiency and robustness of such hybrid approach were investigated as a function of the uncertainty range of the parameters, using simulated data sets. The discussed results demonstrate superior performance of the hybrid genetic algorithm in fitting of complex spectra in comparison to the common Monte Carlo method joint with the Powell refinement.
Źródło:
Acta Physica Polonica A; 2005, 108, 1; 95-102
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement and Analysis of the Positron Annihilation Lifetime Spectra for Mesoporous Silica
Autorzy:
Zaleski, R.
Powiązania:
https://bibliotekanauki.pl/articles/2047164.pdf
Data publikacji:
2006-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
36.10.Dr
61.43.Gt
81.07.-b
41.75.Fr
Opis:
Positron annihilation lifetime spectroscopy as a technique of porous materials investigation is still under development. Both measurement conditions and lifetime spectra analysis methods have to be adapted to the requirements of positron porosimetry. If complex positron annihilation lifetime spectra of porous materials are processed, numerical methods of lifetime spectra analysis have to be used with a particular care. Among various methods of positron annihilation lifetime spectra analysis available, the most popular ones were tested implemented in programs MELT and LT. It was found, from the simulated spectra study, that a large number of counts in a spectrum is needed to obtain reliable results of analysis. Even then only an approximate solution is available. Determination of the approximation nature helps in a further interpretation of the results and in positron annihilation lifetime spectrometer setting adequate to the problem. For this purpose, a few complex spectra obtained from positron beam facility were tested. The results show a negligible influence of resolution function on long lifetime components, while the precise estimation of the background level is crucial. Also some distortions caused by imperfection of numerical analysis methods are pointed out.
Źródło:
Acta Physica Polonica A; 2006, 110, 5; 729-738
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Properties of Spark Plasma Sintered Al-Zn-Mg-Cu Alloy
Autorzy:
Becker, H.
Dopita, M.
Stráská, J.
Málek, P.
Vilémová, M.
Rafaja, D.
Powiązania:
https://bibliotekanauki.pl/articles/1402091.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Bx
81.20.Fw
81.40.-z
81.70.-q
61.43.Gt
81.20.Ev
62.20.M-
Opis:
The microstructure of an aluminum alloy containing 53 wt% Zn, 2.1 wt% Mg and 1.3 wt% Cu as main alloying elements has been studied with the focus on the precipitation behavior during the spark plasma sintering process. The starting material was an atomized Al-Zn-Mg-Cu powder with the particle size below 50 μm. The particles showed a solidification microstructure from cellular to columnar or equiaxed dendritic morphology with a large fraction of the alloying elements segregated in form of intermetallic phases, mainly (Zn,Al,Cu)₄₉Mg₃₂ and Mg₂(Zn,Al,Cu)₁₁, at the cell and dendrite boundaries. The microstructure of the sintered specimens followed the microstructure of the initial powder. However, Mg(Zn,Al,Cu)₂ precipitates evolve at the expense of the initial precipitate phases. The precipitates which were initially continuously distributed along the intercellular and interdendritic boundaries form discrete chain-like structures in the sintered samples. Additionally, fine precipitates created during the sintering process evolve at the new low-angle boundaries. The large fraction of precipitates at the grain boundaries and especially at the former particle boundaries could not be solved into the matrix applying a usual solid solution heat treatment. A bending test reveals low ductility and strength. The mechanical properties suffer from the precipitates at former particle boundaries leading to fracture after an outer fiber tensile strain of 3.8%.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 602-605
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
At the Tip of an MeV Beam: Provoking Cells and Performing Tomographic Imaging
Autorzy:
Pallon, J.
Arteaga-Marrero, N.
Nilsson, Ch.
Elfman, M.
Kristiansson, P.
Nilsson, C.
Wegdén, M.
Olsson, M.
Åkerström, B.
Powiązania:
https://bibliotekanauki.pl/articles/1808531.pdf
Data publikacji:
2009-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.79.-v
29.40.Wk
87.53.-j
87.53.Ay
25.40.Cm
29.30.Ep
29.30.Kv
61.43.Gt
Opis:
Biological applications of ion beams have recently become a new important research field using single ion hit facilities to study individual living cells and their response to the hit of a counted number of ions. One motivation is the search for a better understanding of the fundamental processes taking place in cells and organs as a result of irradiation. Another comes from the increasing interest in using high energy protons and heavy ions as a modality for radiotherapy of deep seated tumours. In the view of treatment efficiency, study of cell culture behaviour under controlled radiation experiments, and in different chemical environments at single ion hit facilities, is a first step towards a better understanding of the processes. Tomographic techniques are applicable to situations where you need information of the inside of an object but do not want to section it into thin slices or cannot do it. Using focused MeV ion beams for tomography restricts the sample size to the order of 10-100 μm, depending of the initial energy. On the other hand, the ability to focus at a sub-micrometer level makes ion beams well suited for analyses of small sized objects as cells, spores, etc. The scanning transmission ion microscopy mode of tomography gives the mass density and corresponding morphological structure of holes and pores. It can then be used to correct the results from the other mode, particle induced X-ray emission tomography. Here is discussed a porosity analysis of bentonite clay that is planned to form an important buffer zone around canisters filled with spent nuclear reactor fuel waste deposited 500 m underground in Sweden.
Źródło:
Acta Physica Polonica A; 2009, 115, 2; 501-506
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Novel Route to Prepare Magnetic Material $Co_3V_2O_8$ and Structural Characterization
Autorzy:
Celik, G.
Kurtulus, F.
Guler, H.
Powiązania:
https://bibliotekanauki.pl/articles/1491310.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.85.-m
32.30.Rj
33.20.Ea
61.43.Gt
61.66.Fn
65.40.-b
75.47.Lx
81.40.Gh
82.33.Pt
84.40.-x
Opis:
$Co_3V_2O_8$ is a member of kagomé staircase oxides, represented by general formula $M_3V_2O_8$ (M = Ni, Co, Mn). It attracted great attention due to strong magnetic anisotropy, magnetic phase transition, genuine macroscopic quantum effects, strong quantum fluctuations, low-temperature ferroelectricity, field-induced magnetic transitions, complicated phase diagram and displays long-range magnetic order because of geometrical frustration. Different routes to prepare the frustrated magnetic material was reported such as floating zone technique and conventional high temperature method. $Co_3V_2O_8$ (International Centre for Diffraction Data (ICDD): 16-675) was synthesized with $Co_3O_4$ (ICDD: 80-1536) as binary phase by microwave assisted preparation using $Co(NO_3)_2 ·6H_2O$ and $NH_4VO_3$. The synthesized material was characterization by powder X-ray diffraction, the Fourier transform infrared spectroscopy, and thermogravimetric-differential thermal analysis.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 203-204
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Luminescence of Lanthanides from Xerogels Embedded in Mesoporous Matrices
Autorzy:
Gaponenko, N.
Powiązania:
https://bibliotekanauki.pl/articles/1814047.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Fw
83.80.Jx
81.05.Rm
78.55.Mb
61.43.Gt
82.45.Cc
42.70.Qs
78.55.Ap
78.60.-b
Opis:
The report summarizes peculiarities of synthesis and luminescence properties of porous silicon, porous anodic alumina and artificial opals with the inclusions of sol-gel derived oxides (xerogels), doped with Er, Tb, and Eu. Origin of strong luminescence of lanthanides from xerogels in mesoporous matrices is discussed.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 737-749
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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