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Wyszukujesz frazę "81.07.De" wg kryterium: Temat


Tytuł:
Functionalization and characterization of MWCNT produced by different methods
Autorzy:
Tomova, A.
Gentile, G.
Grozdanov, A.
Errico, M.
Paunović, P.
Avella, M.
Dimitrov, A.
Powiązania:
https://bibliotekanauki.pl/articles/1070616.pdf
Data publikacji:
2016-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.De
Opis:
The subject of this study is chemical functionalization as means of structural modification of multiwalled carbon nanotubes. The main goal of the experiments was to create highest density of carboxyl groups on multiwalled carbon nanotubes surface, necessary for further nanocomposite application. Two different types of multiwalled carbon nanotubes (I: outer diameter d=50÷ 100 nm, purity ≈84%, synthesized by pyrolysis and II: outer diameter d=10÷40 nm, purity ≈94%, synthesized by chemical vapor deposition) were treated by concentrated nitric acid (HNO₃) and by alkaline mixture (NH₄OH+H₂O₂). The alkaline medium as "milder" and less aggressive than nitric acid, was expected to be less destructive and cause minimal structural damage on multiwalled carbon nanotubes surface. Structural changes due to oxidation were observed by the Raman analysis, while the ratio of the intensities of the D and G peak was used to estimate the concentration of defects. Pristine and functionalized multiwalled carbon nanotubes were characterized by thermogravimetric analysis, scanning electron microscopy, ultraviolet-visible spectroscopy and zeta (ζ) spectroscopy. The results showed that functionalization initiates changes in carbon nanotubes structure as well as in their density of states. It also results in carbon nanotubes shortening and exfoliation and decreases their agglomeration tendency. Carbon nanotubes functionalized by both acid and alkaline treatment can successfully replace conventional carbon fibers as fillers in polymer composites for sensing application.
Źródło:
Acta Physica Polonica A; 2016, 129, 3; 405-408
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of carbon nanomaterials over Ni/ZSM-5 catalyst using simplex method algorithm
Autorzy:
Majewska, J.
Michalkiewicz, B.
Powiązania:
https://bibliotekanauki.pl/articles/1075535.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.De
81.16.Hc
81.15.Gh
Opis:
Carbon nanomaterials were prepared from methane by catalytic decomposition over a nickel-supported ZSM-5 catalyst. The mole ratio of SiO₂ to Al₂O₃ in ZSM-5 was 200-400. The nickel content was varied from 17 to 23 wt% Ni. In order to find the greatest yield and the highest quality of carbon nanomaterials the simplex design method for planning the experiments was applied. Different parameters such as: temperature, methane flow, nitrogen flow and nickel content in the catalyst were evaluated. The carbon nanomaterials were analyzed by the Raman spectroscopy, scanning and transmission electron microscopy, and total organic carbon analyzer.
Źródło:
Acta Physica Polonica A; 2016, 129, 1; 153-157
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Production of Y-Ba-Cu-O Nanowires and Nanotubes by Electrochemical Method
Autorzy:
Kaya, H.
Atalay, F.
Avsar, D.
Yagmur, V.
Atalay, S.
Powiązania:
https://bibliotekanauki.pl/articles/1399690.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.Gf
81.07.De
81.15.Pq
74.78.-w
Opis:
In this work, the technological aspects of great importance $YBa_2Cu_3O_{7-x}$ superconducting materials were produced in the form of nanotube by electrochemical method. The electrochemical deposition conditions for the Y-Ba-Cu deposition in nanoporous $Al_2O_3$ were investigated. The heat treatment was applied to $Y-Ba-Cu//Al_2O_3$ nanopatterns, to form superconductive phase. The resulting nanostructures were found to be in length 4-5 μm, 177-210 nm in diameter. The produced nanostructures at - 4 V and more positive potentials were Y-Ba-Cu nanowires, while the nanostructures deposited at the more negative potentials were of nanotube form.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 209-211
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Interference Effects in Visible-Near Infrared Spectral Range for Arrays of Vertically Aligned Multiwalled Carbon Nanotubes
Autorzy:
Wąsik, M.
Judek, J.
Świtkowski, K.
Zdrojek, M.
Powiązania:
https://bibliotekanauki.pl/articles/1030331.pdf
Data publikacji:
2017-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Ci
78.67.Ch
81.07.De
Opis:
Based on the reflectance spectra for radiation wavelength from about 380 nm to 1.8 μm, the optical interference effects in vertically aligned multiwalled carbon nanotubes films are studied. We performed the measurements for two complementary polarization states of incoming radiation (s- and p-polarization) for nanotubes arrays sparse enough for interference effects to be possible to observe. By performing the measurements for different wavelengths and incidence angles, we mapped the evolution of interference maxima/minima of reflectance signal. The results from this novel approach indicate that for the radiation polarized perpendicularly to tubes axis (s-polarization), the real part of the effective refractive index can be estimated from the classic Fabry-Pérot model. In order to describe the differences between spectra obtained for s- and p-polarizations we discuss the most important factors that affect the reflectance signal in case of investigated nanotubes arrays.
Źródło:
Acta Physica Polonica A; 2017, 131, 2; 232-236
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrochemical Capacitance of Cobalt Oxide Nanotubes on Nickel Foam
Autorzy:
Yagmur, V.
Atalay, F.
Kaya, H.
Avcu, D.
Aydogmus, E.
Powiązania:
https://bibliotekanauki.pl/articles/1399695.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.De
82.47.Uv
88.80.fh
Opis:
In this study, densely packed $Co_3O_4$ nanotubes for supercapacitors have been obtained by means of chemically depositing cobalt hydroxide within a porous anodic aluminum oxide and then annealed at 360°C. The morphological properties obtained $Co_3O_4$ nanotubes were studied by scanning electron microscopy, the chemical composition was determined by examination of the energy dispersive X-ray spectra. Supercapacitor characteristics such as charging/discharging and impedance (Z) characteristics were also examined.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 215-217
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrochemical Formation of Self-Organized Nanotubular Oxide Layers on Ti13Zr13Nb Alloy for Biomedical Applications
Autorzy:
Smołka, A.
Rodak, K.
Dercz, G.
Dudek, K.
Łosiewicz, B.
Powiązania:
https://bibliotekanauki.pl/articles/1361071.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.jj
81.07.De
87.85.J-
Opis:
In this work, the anodic formation of self-organized nanotubular oxide layers on Ti13Zr13Nb implant alloy was presented. Anodic oxidation was carried out at room temperature in [1 M] $(NH_4)_2SO_4$ solution with 1 wt% content of $NH_4F$. The voltage and time of anodization was 20 V for 120 min, respectively. Under proposed conditions, the best arrangement of nanopores was observed. The physical and chemical properties of the anodized surface of the Ti13Zr13Nb alloy were characterized using grazing incidence X-ray diffraction, scanning transmission electron microscopy, and atomic force microscopy. It was found that diameter of nanopores varied from 10 to 32 nm. Mechanism of the fabrication of the unique 3D tube-shaped nanostructure of $TiO_2$ on the surface of the Ti13Zr13Nb alloy by electrochemical anodization, has been discussed.
Źródło:
Acta Physica Polonica A; 2014, 125, 4; 932-935
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrochemical formation of second generation TiO₂ nanotubes on Ti13Nb13Zr alloy for biomedical applications
Autorzy:
Stróż, A.
Dercz, G.
Chmiela, B.
Stróż, D.
Łosiewicz, B.
Powiązania:
https://bibliotekanauki.pl/articles/1153606.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.jj
81.07.De
82.47.-a
Opis:
The aim of this study was to obtain the second generation TiO₂ nanotubes on the Ti13Nb13Zr alloy. Anodic oxidation of the alloy under study was carried out in 1 M (NH₄)₂SO₄ electrolyte under voltage-time conditions of 20 V for 120 min. The morphological parameters of the obtained nanotubes of second generation such as the length (L), internal (D_{i}) and outer (D_{o}) diameter of nanotube were determined. It was found that the anodic oxidation of the Ti13Nb13Zr alloy conducted under proposed conditions allowed to obtain the single-walled nanotubes of the following geometrical parameters: the internal diameter 61 nm, outer diameter 103 nm, and the length 3.9 μm. The total surface area of the single-walled nanotubes was equal to 4.1 μm², and the specific surface area per cm² (A_{s}) was estimated to be 15.6 cm²/cm². Formation mechanism, structure and optimal morphological parameters of the obtained single-walled nanotubes on the Ti13Nb13Zr alloy have been discussed in detail.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 1079-1080
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dispersive Micro Raman Backscattering Spectroscopy Investigation of Arc Discharge Synthesized CNTs Doped by Boron and Nitrogen
Autorzy:
Babanejad, S.
Malekfar, R.
Seyyed Hosseini, S.
Powiązania:
https://bibliotekanauki.pl/articles/1807785.pdf
Data publikacji:
2009-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Fg
63.22.Gh
78.67.Ch
81.07.De
Opis:
Raman scattering studies reveal the remarkable structure and the unusual electronic and phonon properties of carbon nanotubes. In this study, we directly produced boron, B, and nitrogen doped carbon nanotubes by using DC-arc discharge method which normally can be employed for producing carbon nanotubes. We performed experiments without using catalysts and in the presence of Ar gas for producing boron doped carbon nanotubes. At the second and third stages and in the presence of $Al_{2}O_{3}$ and MgO nanopowders as catalysts and nitrogen gas were used for producing nitrogen doped carbon nanotubes. In general, our investigation revealed that some major changes caused by B and N dopants can be observed in the related recorded Raman spectra.
Źródło:
Acta Physica Polonica A; 2009, 116, 2; 217-220
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of the Silanization Processes on the Properties οf Oxidized Multiwalled Carbon Nanotubes
Autorzy:
Scheibe, B.
Borowiak-Palen, E.
Kalenczuk, R.
Powiązania:
https://bibliotekanauki.pl/articles/1807640.pdf
Data publikacji:
2009-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.65.Mq
81.07.De
61.48.De
65.80.-g
68.37.Lp
Opis:
This paper presents the results of the research on the effect of the two different silanization methods on the thermal and structural properties of oxidized multiwalled carbon nanotubes. As-purified material was oxidized in the mixture of nitric and sulfuric acids. An oxidized material was divided into two parts which underwent two silanization treatments by 3-aminopropyltriethoxysilane (APTES). The first experiment (I) was performed at room temperature in acetone (pH 7) for 30 min. The second experiment (II) involved a hydrolysis of APTES at 40°C in water (pH 4) for 3 h. The functionalization extent of the samples at each step of the preparation was investigated by the Raman spectroscopy. The presence of the functional groups on the nanotubes surface have been studied via the Fourier transform infrared spectroscopy (FT-IR). The quantity of the external moieties introduced on multiwalled carbon nanotubes surface after oxidation process was estimated by the Boehms titration method. The high resolution transmission electron microscopy analysis allowed us to observe the changes of the morphology of the investigated carbon nanotubes. The influence of the silanization processes on the thermal stability of multiwalled carbon nanotubes was thoroughly studied by thermogravimetry analysis. There was observed a significant increase of the thermal stability of the multiwalled carbon nanotubes samples upon silanization treatment in respect of pristine and oxidized multiwalled carbon nanotubes.
Źródło:
Acta Physica Polonica A; 2009, 116, S; S-150-S-155
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Increase of Hydrogen Storage Capacity of CNTs by Using Transition Metal, Metal Oxide-CNT Nanocomposites
Autorzy:
Larijani, M.
Safa, S.
Powiązania:
https://bibliotekanauki.pl/articles/1205209.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.82.Rx
68.37.Lp
81.07.De
88.30.R-
Opis:
In this paper, we examined the synergetic effect of transition metals or their oxides as decorative agent with carbon nanotubes on the hydrogen storage capacity. The $TiO_2$, Pd, and PdO shell nanoparticles were used as decorative agent on the surface of carbon nanotubes. The samples were investigated by X-ray diffraction, Raman spectroscopy and transmission electron microscopy. The thermal stability was investigated by thermogravimetric analysis testing. The hydrogen storage capacity was measured by a custom-made Sieverts apparatus. The Pd and $TiO_2$ doped carbon nanotube shows the most marked hydrogen storage capacity, 7 times higher than pristin carbon nanotubes after 30 min storage. The results show that the hydrogen storage capacity of the PdO shell- carbon nanotube composite is very low in comparison with those of two others and does not represent a significant difference with that of carbon nanotubes.
Źródło:
Acta Physica Polonica A; 2014, 126, 3; 732-735
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Raman Study on Doped Multiwalled Carbon Nanotubes
Autorzy:
Costa, S.
Borowiak-Palen, E.
Powiązania:
https://bibliotekanauki.pl/articles/1807799.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Ch
73.22.-f
81.07.De
61.72.Ww
63.20.-e
Opis:
In the present study we report resonance Raman study on multiwalled carbon nanotubes treated with HCl, $HNO_3$ and $H_2SO_4$. Acids are commonly used in purification procedures in order to remove catalyst particles from the as-produced material. However, it is known that acid treatments in multiwalled carbon nanotubes can induce a surface functionalisation and intercalation of the walls, modifying their electronic properties. Here, we present a comparative study between samples of multiwalled carbon nanotubes modified with the most common acids used in the purification of carbon materials, and the influence of the acid treatment time on their vibronic properties. The samples were analysed via the Raman spectroscopy using the laser length of 785 nm. The presented data reveal the modification of the typical multiwalled carbon nanotubes Raman bands such as: disorder band (D band), the graphite band (G band), and the two-phonon second order Raman band (G' band). The last one shows a broadening effect on its line shape and the appearance of an additional peak. All the treatments enhance the number of defects in the graphitic structure of multiwalled carbon nanotubes.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 32-35
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonance Raman Study on Carbon Nanotubes Formation
Autorzy:
Steplewska, A.
Borowiak-Palen, E.
Powiązania:
https://bibliotekanauki.pl/articles/1807842.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Fg
61.46.Np
81.07.De
78.30.-j
61.46.+w
Opis:
Carbon nanotubes can be obtained from variety of the molecular precursors in chemical vapor deposition processes. The low growth temperatures strongly increase the compatibility of carbon nanotubes growth with current complementary metal-oxide-silicon technology for carbon nanotubes-based electronics. Here, we show the low temperature growth of multiwalled carbon nanotubes in acetylene chemical vapor deposition with Fe-Co/MgO. The catalyst mix was active already at 450°C. The higher temperatures growth (500°C and 550°C) were also tested in order to estimate the best thermal condition in respect of the sample quality (via thermogravimetric analyzer) and the sample relative purity (via resonance Raman spectroscopy). High resolution transmission electron microscope was used to determine the morphology of the samples.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 93-95
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Analysis of Magnetic Inclusions in Nanomaterials Based on Multiwall Carbon Nanotubes
Autorzy:
Brzózka, K.
Krajewski, M.
Małolepszy, A.
Stobiński, L.
Szumiata, T.
Górka, B.
Gawroński, M.
Wasik, D.
Powiązania:
https://bibliotekanauki.pl/articles/1032146.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.Qr
61.46.Fg
61.48.De
75.50.Tt
75.75.Cd
81.07.De
Opis:
Functionalized multiwall carbon nanotubes as well as nanocomposite based on that material covered by nanoparticles composed of iron oxides were the subject of investigations. In order to identify all iron-bearing phases including those reported on the base of previous X-ray diffraction measurements, the transmission Mössbauer spectroscopy was utilized. The experiments were carried out both at room temperature and also at low temperatures. It was stated that in the investigated nanotubes some impurities were present, originating from the catalyst remains, in form of Fe-C and α -Fe nanoparticles. The Mössbauer spectra collected for the nanocomposite showed a complex shape characteristic of temperature relaxations. The following subspectra related to iron-based phases were identified: sextet attributed to hematite, with hyperfine magnetic field reduced due to the temperature relaxations, sextet corresponding to iron carbide as well as two doublets linked to superparamagnetic hematite and ferrihydrites.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 863-865
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ab Initio Study of Functionalized Carbon Nanotubes
Autorzy:
Milowska, K.
Birowska, M.
Majewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791295.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.15.ae
31.15.E-
61.46.Fg
61.48.De
73.22.-f
81.07.De
Opis:
In the present paper, we study the stability of (9, 0), (10, 0), (11, 0) carbon nanotubes functionalized with simple organic molecules $-CH_{n}$ (for n = 2, 3, 4). Our studies are based on ab initio calculations within the framework of the density functional theory. We determine binding energies of the functionalized carbon nanotubes and the changes in the geometry and electronic structure caused by the functionalization. We observe the characteristic effects such as rehybridization of the bonds induced by fragments attached to carbon nanotubes and pentagon/heptagon (5/7) defects in $-CH_{2}$ functionalized carbon nanotubes. We study also dependence of the binding energies of the functionalized carbon nanotubes on the density of the adsorbed molecules and diameter of the single-wall carbon nanotubes. Our calculations reveal that the $-CH_{2}$ fragments exhibit the strongest cohesion and we determine the critical density of the $-CH_{2}$ fragments which could be adsorbed.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 841-843
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
$TiO_2$ Nanotube Array as Efficient Transparent Photoanode in Dye-Sensitized Solar Cell with High Electron Lifetime
Autorzy:
Lamberti, A.
Sacco, A.
Hidalgo, D.
Bianco, S.
Manfredi, D.
Quaglio, M.
Tresso, E.
Pirri, C.
Powiązania:
https://bibliotekanauki.pl/articles/1399940.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Bd
72.20.Jv
72.40.+w
73.40.Mr
88.40.H-
81.07.De
Opis:
In the present work, the fabrication and characterization of non-curling, free-standing $TiO_2$ nanotube membranes and their integration in front-side illuminated dye-sensitized solar cells are reported. Vertically oriented $TiO_2$ nanotube arrays were fabricated by anodic oxidation of a titanium foil. Nanotube membranes were detached from the metallic foil, transferred and bonded on transparent fluorine-doped tin oxide/glass substrates employing a $TiO_2$ sol as a binder. Crystalline phase and morphology of the film were investigated, evidencing the formation of a highly ordered 1D nanotubes carpet, with a pure anatase crystalline structure. $TiO_2$ nanotube-based DSCs were fabricated using reversible microfluidic architecture. The cell performances were studied by I-V electrical characterization, incident-photon-to-electron conversion efficiency, electrochemical impedance spectroscopy and open circuit voltage decay measurements, showing an increase in electron lifetime compared to nanoparticle-based dye-sensitized solar cells.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 376-379
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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