An simple technique for synthesis of carbon nanotubes by underwater arc plasma

Applicable, low cost technique for the production of carbon nanotubes by underwater (or solution) AC arc plasma discharge is described. The growth takes place in an AC arc in water solution between graphite electrodes.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Biocompatible nanostructure materials

Materials suitable for medical systems have always been the product of interdisciplinary collaboration between material and biological science. As well as different area of physics and chemistry. For medical application materials must not damage blood cells or bones and must be resistant. Some implant materials for chemical bonds can be stabilized by implantation of different elements or deposition of very thin films. In this work we presented some results for replacement of damaged human tissues.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Prepoznavanje faza koje sadrže Fe u mikrostrukturi livene legure AA6026 i njihova evolucija tokom postupka homogenizacije

The Fe-bearing intermetallic phases present in the as-cast AA6026 alloy and their evolution during homogenization treatments at 480-550°C were investigated using optical microscopy, SEM, and TEM techniques in combination with EDS analysis. In addition to the α-Al(Fe,Mn)Si phase with dendritic morphology, two types of plate-like Fe-bearing microconstituents were revealed in the microstructure of the as-cast alloy. The EDS microanalysis and electron diffraction showed that one set of platelets represented thin sections of α-Al(Fe,Mn)Si microconstituent. The other set of plate-like microconstituents was identified as a tetragonal, silicon-rich δ-Al4(Fe,Mn)Si2 phase. The formation of the δ-Al4(Fe,Mn)Si2 phase was attributed to the chemical composition of the alloy. During homogenization, the metastable δ-Al4(Fe,Mn)Si2 transformed into the α-Al(Fe,Mn)Si phase and fragmented. The dendritic α-Al(Fe,Mn)Si microconstituents underwent fragmentation. However, while the α-Al(Fe,Mn)Si microconstituents preserved a b.c.c. crystal lattice throughout the process, the product of the transformation of the δ-Al4(Fe,Mn)Si2 phase exhibited primitive cubic lattice.Ispitivanje prisustva faza koje sadrže Fe u mikrostrukturi livene legure AA6026, kao i njihova evolucija tokom postupaka homogenizacije na temperaturama od 480-550 °C, sprovedena su korišćenjem optičke mikroskopije, skenirajuće elektronske mikroskopije (SEM) i transmisione elektronske mikroskopije (TEM) u kombinaciji sa analizom EDS-a. Osim faze α-Al(Fe,Mn)Si sa dendritskom morfologijom, identifikovane su dve vrste pločastih mikrokonstituenata koji sadrže Fe u mikrostrukturi livene legure. EDS mikroanaliza i elektronska difrakcija pokazali su da jedan skup ploča predstavlja samo tanke sekcije mikrokonstituente α-Al(Fe,Mn)Si. Drugi skup pločastih mikrokonstituenata identifikovan je kao četvrtasta, silicijumom bogata faza δ-Al4 (Fe,Mn)Si2 . Formiranje faze δ-Al4 (Fe,Mn)Si2 povezano je sa hemijskim sastavom legure. Tokom homogenizacije, metastabilna faza δ-Al4 (Fe,Mn)Si2 transformisala se u fazu α-Al(Fe,Mn)Si i fragmentirala. Dendritski mikrokonstituenti α-Al(Fe,Mn)Si takođe su fragmentirali. Međutim, dok su mikrokonstituenti α-Al(Fe,Mn)Si sačuvali kubnu kristalnu rešetku tipa b.c.c. tokom procesa, proizvod transformacije faze δ-Al4 (Fe,Mn)Si2 pokazao je prostu kubnu rešetku

Ion-beam irradiation effects on reactively sputtered CrN layers

This paper presents a study of microstructural changes induced in CrN layers by irradiation with 120 keV argon ions. The layers were deposited on (100) Si wafers, at different nitrogen partial pressures (2×10^-4, 3.5×10^-4 and 5×10^-4 mbar), to a total thickness of 260–280 nm. During deposition the substrates were held at 150°C. After deposition the samples were irradiated with argon ions to the fluences of 1×10^15 and 1×10^16 ions/cm2, under the vacuum of 7×10^-6 mbar. Characterisation of the samples structure and morphology were performed by X-ray diffraction (XRD) analysis and cross-sectional transmission electron microscopy (XTEM), and the concentration profiles were determined by Rutheford backscattering (RBS) spectrometry. It was found that the layer composition strongly depends on the nitrogen partial pressure during deposition. A pure stoichiometric CrN phase was achieved for the highest nitrogen partial pressure (5×10^-4 mbar). Argon ions irradiation induces microstructural changes in the CrN layers such as variation of the lattice constants, micro-strain and mean grain size.Paper presented at 4th Serbian Conference on Electron Microscopy, Belgrade, Serbia, 201

Argon Irradiation Effects on the Structural and Optical Properties of Reactively Sputtered CrN Films

The present study deals with CrN films irradiated at room temperature (RT) with 200 keV Ar+ ions. The CrN layers were deposited by d.c. reactive sputtering on Si (100) wafers, at nitrogen partial pressure of 5x10(-4) mbar, to a total thickness of 280 nm. The substrates were held at 150 degrees C during deposition. After deposition the CrN layers were irradiated with 200 keV Ar+ ions to the fluences of 5x10(15) - 2x10(16) ions/cm(2). Structural characterization was performed with Rutherford backscattering spectroscopy (RBS), cross-sectional transmission electron microscopy (XTEM) and X-ray diffraction (XRD). Spectroscopic ellipsometry measurements were carried out in order to study optical properties of the samples. The irradiations caused the microstructrual changes in CrN layers, but no amorphization even at the highest argon fluence of 2x10(16) ions/cm(2). Observed changes in microstructure were correlated with the variation in optical parameters. It was found that both refractive index and extinction coefficient are strongly dependent on the defect concentration in CrN layers

Annealing effects on the properties of TiN thin films

The structure, absorption coefficient and electrical resistivity studies on TiN thin films are presented. The film of thickness 240 nm was grown on Si (100) substrate by DC reactive sputtering at an average deposition rate of similar to 8 nm/min. After deposition the samples were annealed for 1 h at 600 degrees C and 2 h at 700 degrees C in nitrogen ambient and vacuum furnace, respectively. Structural characterizations were performed by Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The optical properties were investigated by spectroscopic ellipsometry while a four point probe was used for electrical characterization. It was found that the post-deposition annealing of the films did not cause any variation in stoichiometry, but strongly affects the structural parameters such as lattice constant, micro-strain and grain size. The observed increase in the grain size after annealing leads to significantly lower value of the coefficient of absorption. These changes could be directly correlated with variation of electrical properties of TiN thin films

Proizvodnja goveđeg mesa obogaćenog organski vezanim selenom

In this study, the effects of the organic and inorganic form of selenium, in the diet for finishing beef cattle, were investigated. Sell-Plex produced by American firm Alltech as a source of organic selenium with selenium concentration of 2000 mg/kg was used. The source of inorganic selenium was sodium selenite. The trial was conducted on Simmental fattening cattle in the final stage in the free housing system and it lasted 60 days. Selenium content in control and trial group (m. longissimus dorsi) was 78.65 and 125.03 μg/kg (P (lt) 0.01), in kidneys 855.52 and 1026.04 μg/kg(P (lt) 0.001); in liver 453.13 and 534.64 μg/ kg(P (lt) 0.01) and in spleen 308.44 and 383.62 μg/kg (P (lt) 0.001), respectively. There were no differences in main carcass characteristics, share of some tissues in the round and three rib chops, chemical composition and meat quality of m. longissimus dorsi (P>0.05).Considering the higher storage of organic selenium in meat and internal organs of the fattening cattle with respect to the inorganic form, it was concluded that the selenium supply in organic form has a better bioavailability. Inclusion of organic selenium into the diet in the final stage of fattening cattle and its deposition in meat and internal organs is a good and easy way to get meat with functional foods properties that in addition to nutritional value should positively affect human health.U radu su ispitani efekti organskog i neorganskog selena u obrocima junadi u tovu. Kao ozvor organskog selena korišćen je preparat Sell-Plex u kome je koncentracija selena iznosila 2000 mg/kg a izvor neorganskog selena bio je natrijumselenit. Ogled je izveden na Simentalskoj rasi goveda u završnoj fazi tova u slobodnom sistemu držanja i trajao je 60 dana. Sadržaj selena u m. longissimus dorsi, jetri, slezini i bubrezima bio je značajno viši na ishranbenom tretmanu sa organskim selenom u odnosu na neorganski, što ukazuje na njegovu bolju bioiskoristivost. Urađena je disekcija polutke prema zvanično važećoj skali za klasifikaciju trupova odraslih goveda propisanoj od strane evropske zajednice. Dobijeni rezultati ukazuju da nije bilo razlike između tretmana sa organskim i neorganskim selenom u telesnoj masi grla pre klanja kao i glavnim karakteristikama polutke. Takođe, nije bilo razlike u udelu pojedinih tkiva u butu i trorebarnom isečku kao i ni u hemijskom sastavu i kvalitetu mesa u m. longissimus dorsi. Imajući u vidu da je selen esencijalan mikroelement u ishrani a da organski vezan selen ima bolju bioiskoristivost u odnosu na neorganski, njegovo uključivanje u obroke goveda i deponovanje u mesu i unutrašnjim organima je dobar i jednostavan način za dobijanje mesa sa svojstvima funkcionalne hrane koja treba da pored nutritivne vrednosti pozitivno utiče na zdravlje ljudi. Pošto su pojedini delovi planete Zemlje slabo opskrbljeni sa selenom ovo je najjednostavniji način da se reši problem njegovog deficita

Structural changes induced by argon ion irradiation in TiN thin films

In this work, the effects of 120 keV Ar+ ion implantation on the structural properties of TiN thin films were investigated. TiN layers were deposited by d.c. reactive sputtering on Si(100) wafers at room temperature or at 150°C. The thickness of TiN layers was ~240 nm. After deposition the samples were irradiated with 120 keV argon ions to the fluencies of 1×10^15 and 1×10^16 ions/cm2. Structural characterisation was performed with Rutherford backscattering spectroscopy (RBS), cross-sectional transmission electron microscopy (XTEM), grazing angle X-ray diffraction (XRD) and atomic force microscopy (AFM). It was found that the argon ion irradiation induced the changes in the lattice constant, mean grain size, micro-strain and surface morphology of the TiN layers. The observed micro-structural changes are due to the formation of the high density damage region in the TiN thin film structure.Paper presented at 4th Serbian Conference on Electron Microscopy, Belgrade, Serbia, 201

Helical and square-spiral copper nanostructures: The effect of thickness and deposition conditions on the structural and optical properties

We have investigated the effect of thickness and deposition conditions on the structural and optical properties of nanostructured copper (Cu) thin films, deposited using e-beam glancing angle deposition. In the first series of experiments, samples were deposited in the form of helical nanostructures, to the thicknesses of 160 nm, 280 nm, 450 nm and 780 nm. The second set of the samples was fabricated in the form of zigzag and square-spiral nanostructures to a thickness of approximately 300 nm, by using different azimuthal rotations (φ = 180o, 90o, 45o, 22.5o and 11o). Field-emission scanning electron microscopy and high-resolution transmission electron microscopy were utilized to explore morphological and structural properties, while optical studies were done using spectroscopic ellipsometry. The results showed that for both series of the samples the deposited structures are porous with nanometer-sized particles. Detailed analyses of optical properties revealed that the thickness of the films had a significant impact on the dielectric function of Cu structures. With increasing the thickness from 160 nm to 780 nm the surface plasmon resonance (SPR) peak was shifted from 1.31 eV to 1.05 eV. Changes in SPR peak position were associated with the growth mechanism and the size of deposited nanostructures. For the second series of the samples, it was found that as the azimuthal rotation decreases, deposited nanostructures become more porous with larger number of grown arms. Optical analysis showed that the properties of the grown Cu films are greatly influenced by the deposition conditions. By decreasing the φ parameter, SPR peak was shifted from 1.19 eV to 0.75 eV, which can be correlated with the size distribution and agglomeration of Cu nanoparticles.IX International School and Conference on Photonics : PHOTONICA2023 : book of abstracts; August 28 - September 1, 2023; Belgrad

Structural, optical and electrical properties of reactively sputtered CrxNy films: Nitrogen influence on the phase formation

The properties of various CrxNy films grown by direct current (DC) reactive sputtering process with different values of nitrogen partial pressures (0, 2x10(-4), 3.5x10(-4) and 5x10(-4) mbar) were studied. The structural analysis of the samples was performed by using X-ray diffraction and transmission electron microscopy (TEM), while an elemental analysis was realized by means of Rutherford backscattering spectrometry. By varying nitrogen partial pressure the pure Cr layer, mixture of Cr, Cr-2 N and CrN phases, or single-phase CrN was produced. TEM analysis showed that at pN(2) = 2x10(-4) mbar the layer has dense microstructure. On the other hand, the layer deposited at the highest nitrogen partial pressure exhibits pronounced columnar structure. The optical properties of CrxNy films were evaluated from spectroscopic ellipsometry data by the Drude or combined Drude and Tauc-Lorentz model. It was found that both refractive index and extinction coefficient are strongly dependent on the dominant phase formation (Cr, Cr-2 N, CrN) during the deposition process. Finally, the electrical studies indicated the metallic character of Cr-2 N phase and semiconducting behaviour of CrN