15 results on '"Koruga, Đuro"'
Search Results
2. Remanent Magnetization Measurements of the Fullerene Thin Films
- Author
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Duricić, Ivan, Matija, Lidija, Bojović, Božica, Mihajlović, Spomenko, Kosić, Boris, Koruga, Đuro, Duricić, Ivan, Matija, Lidija, Bojović, Božica, Mihajlović, Spomenko, Kosić, Boris, and Koruga, Đuro
- Abstract
Magnetic properties of carbon vary according to its allotropic modifications. Although carbon atom is known as a diamagnetic, some distinctive features point out that its magnetic properties are not that simple. Fullerene C-60, a carbon atoms molecule, is proven to have very different magnetizations than other forms of carbon compounds. Rhombohedral fullerene is shown to have ferromagnetic properties, and thus investigations of fullerene as a magnetic material are necessary. Fullerene C-60 in the form of thin film is also shown to have distinctive magnetic properties. In this paper, remanent magnetization of fullerene thin films, thicknesses of 100 and 250 nm were investigated when films are in the dark and exposed to polarized light. Research showed how light is influencing the material and its magnetization.
- Published
- 2015
3. Actual Diamond Engraving of a Fullerene Coated Glass Plate
- Author
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Bojović, Božica, Petrov, Ljubiša, Matija, Lidija, Koruga, Đuro, Bojović, Božica, Petrov, Ljubiša, Matija, Lidija, and Koruga, Đuro
- Abstract
In this paper, we present the results of fullerene film engraving using a diamond tool. Based on available literature data, to our knowledge the fullerene film machinability is not explored in literature. Therefore, we have investigated wear mechanisms of the engraving process that could be used in micromachining. The engraving process parameters were estimated on the basis of poor quality groove's edge. The flat diamond tip, which remains after wear, has a pitted surface which was observed with a digital optical microscopy and identified using AFM. Soot-like wear debris was observed and spectroscopically analyzed. FTIR spectroscopy results strongly indicate that fullerene C-60 disappears as a molecule and interacts with oxygen, nitrogen and water vapor from the atmosphere. The occurrence of tool wear and wear debris were observed by nondestructive thermography testing. Results confirm that development of high temperature in a cutting zone of 1556 degrees C causes extensive thermo-chemical tool wear.
- Published
- 2015
4. Advances in Chromatographic Separation on Al2O3 and Spectroscopic Characterization of the Higher Fullerenes
- Author
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Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Jovanović, Tamara, Koruga, Đuro, and Jovančićević, Branimir
- Abstract
The basic C-60 and C-70, and the higher fullerenes, mainly C-76 and C-84 were extracted with a series of different and previously unapplied solvents or combinations of solvents, by original advanced procedures, from the samples of carbon soot, produced in electric arc. The solubility of the basic and the higher fullerenes in the applied series of solvents was compared. Chromatographic separations of fullerenes from the obtained extracts were performed by continue elution, in one phase of each process, under atmospheric pressure, with the original, defined gradients of solvents, from pure hexane or 5% toluene in hexane to pure toluene, on active Al2O3 columns, by the new, improved methods. Identifications of fullerenes in all the chromatographically purified fractions and the extracts were performed using determined techniques of IR and UV/VIS spectroscopy that have not been presented previously for the higher fullerenes. The advances in chromatographic purification using alumina, as well as in understanding of the unique and the main optical absorption properties of these molecules are reported.
- Published
- 2014
5. Advances in Chromatographic Separation on Al2O3 and Spectroscopic Characterization of the Higher Fullerenes
- Author
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Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Jovanović, Tamara, Koruga, Đuro, and Jovančićević, Branimir
- Abstract
The basic C-60 and C-70, and the higher fullerenes, mainly C-76 and C-84 were extracted with a series of different and previously unapplied solvents or combinations of solvents, by original advanced procedures, from the samples of carbon soot, produced in electric arc. The solubility of the basic and the higher fullerenes in the applied series of solvents was compared. Chromatographic separations of fullerenes from the obtained extracts were performed by continue elution, in one phase of each process, under atmospheric pressure, with the original, defined gradients of solvents, from pure hexane or 5% toluene in hexane to pure toluene, on active Al2O3 columns, by the new, improved methods. Identifications of fullerenes in all the chromatographically purified fractions and the extracts were performed using determined techniques of IR and UV/VIS spectroscopy that have not been presented previously for the higher fullerenes. The advances in chromatographic purification using alumina, as well as in understanding of the unique and the main optical absorption properties of these molecules are reported.
- Published
- 2014
6. Comparative Spectroscopic Characterization of the Basic and the Higher Fullerenes
- Author
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Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Vajs, Vlatka, Devic, G., Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Vajs, Vlatka, and Devic, G.
- Abstract
The basic C-60 and C-70, and the higher fullerenes, mainly C-76 and C-84, were extracted by original procedures, with p-xylene and the mixture of xylenes from the samples of initial carbon soot, produced in electrical arc. The extracts were obtained in increased and high yields of 6% and 11.9%, respectively, due to application of the advanced procedures. The solubility of fullerenes in these solvents was compared. Chromatographic separation of the basic and the higher fullerenes from the obtained p-xylene extract was performed by continue elution, in one phase of the process, under atmospheric pressure, with original, defined gradient of solvents, from pure hexane to 75% toluene in hexane, on active Al2O3 column, by a new, improved method. Comparative spectroscopic characterization of the obtained purified fullerene fractions and the extracts is reported. The IR and UV/VIS techniques that have not been presented previously for the higher fullerenes were employed as a contribution to better introduction of their optical absorption properties.
- Published
- 2013
7. Comparative Spectroscopic Characterization of the Basic and the Higher Fullerenes
- Author
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Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Vajs, Vlatka, Devic, G., Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Vajs, Vlatka, and Devic, G.
- Abstract
The basic C-60 and C-70, and the higher fullerenes, mainly C-76 and C-84, were extracted by original procedures, with p-xylene and the mixture of xylenes from the samples of initial carbon soot, produced in electrical arc. The extracts were obtained in increased and high yields of 6% and 11.9%, respectively, due to application of the advanced procedures. The solubility of fullerenes in these solvents was compared. Chromatographic separation of the basic and the higher fullerenes from the obtained p-xylene extract was performed by continue elution, in one phase of the process, under atmospheric pressure, with original, defined gradient of solvents, from pure hexane to 75% toluene in hexane, on active Al2O3 column, by a new, improved method. Comparative spectroscopic characterization of the obtained purified fullerene fractions and the extracts is reported. The IR and UV/VIS techniques that have not been presented previously for the higher fullerenes were employed as a contribution to better introduction of their optical absorption properties.
- Published
- 2013
8. Isolation and Characterization of the Higher Fullerenes from Carbon Soot
- Author
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Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Jovanović, Tamara, Koruga, Đuro, and Jovančićević, Branimir
- Abstract
In the first phase of the process, the higher fullerenes, mainly C(76) and C(84), as well as the basic fullerenes C(60) and C(70), in a smaller amount, were Soxhlet extracted with pyridine from the sample of initial carbon soot, produced in electrical arc. The extract was obtained in increased, high yield of 16.4%, due to application of the original procedure. The solubility of fullerenes in this solvent was determined. Chromatographic separation of fullerenes from pyridine extract was performed by continual elution, in one phase of the process, under atmospheric pressure, with original, defined gradient of solvents, from pure hexane to pure toluene, on active Al(2)O(3) column, by a new, improved method. Identifications of fullerenes in the obtained chromatographically purified fractions and pyridine extract of the initial soot were performed using determined IR and UV/VIS techniques that have not been presented previously for the higher fullerenes.
- Published
- 2011
9. Isolation and Characterization of the Higher Fullerenes from Carbon Soot
- Author
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Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Jovanović, Tamara, Koruga, Đuro, and Jovančićević, Branimir
- Abstract
In the first phase of the process, the higher fullerenes, mainly C(76) and C(84), as well as the basic fullerenes C(60) and C(70), in a smaller amount, were Soxhlet extracted with pyridine from the sample of initial carbon soot, produced in electrical arc. The extract was obtained in increased, high yield of 16.4%, due to application of the original procedure. The solubility of fullerenes in this solvent was determined. Chromatographic separation of fullerenes from pyridine extract was performed by continual elution, in one phase of the process, under atmospheric pressure, with original, defined gradient of solvents, from pure hexane to pure toluene, on active Al(2)O(3) column, by a new, improved method. Identifications of fullerenes in the obtained chromatographically purified fractions and pyridine extract of the initial soot were performed using determined IR and UV/VIS techniques that have not been presented previously for the higher fullerenes.
- Published
- 2011
10. Isolation and Characterization of the Higher Fullerenes from Carbon Soot
- Author
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Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Jovanović, Tamara, Koruga, Đuro, and Jovančićević, Branimir
- Abstract
In the first phase of the process, the higher fullerenes, mainly C(76) and C(84), as well as the basic fullerenes C(60) and C(70), in a smaller amount, were Soxhlet extracted with pyridine from the sample of initial carbon soot, produced in electrical arc. The extract was obtained in increased, high yield of 16.4%, due to application of the original procedure. The solubility of fullerenes in this solvent was determined. Chromatographic separation of fullerenes from pyridine extract was performed by continual elution, in one phase of the process, under atmospheric pressure, with original, defined gradient of solvents, from pure hexane to pure toluene, on active Al(2)O(3) column, by a new, improved method. Identifications of fullerenes in the obtained chromatographically purified fractions and pyridine extract of the initial soot were performed using determined IR and UV/VIS techniques that have not been presented previously for the higher fullerenes.
- Published
- 2011
11. Advancement of the Process for Extraction, Chromatography and Characterization of Fullerenes
- Author
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Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Simic-Krstic, J., Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, and Simic-Krstic, J.
- Abstract
In the first phase of this work, the basic C60 and C70 as well as the higher fullerenes, mainly C76 and C84, were Soxhlet extracted with p-xylene and n-heptane from the samples of carbon soot, produced in electrical arc, yielding 5.9% and 0.7% of the extract, respectively. The remaining, p-xylene insoluble soot was then extracted with pyridine, by original advanced method, increasing the entire extract yield for an additional 5.9% to 11.8%. The procedures for increases of the basic and higher fullerenes yields, as well as for additional, selective extraction of the higher fullerenes were found. Chromatographic separation of the basic and the higher C76 and C84 fullerenes from p-xylene extract was performed by continual elution, in one phase of the process, under atmospheric pressure, with original, defined, gradient of solvents from 5% toluene in hexane to pure 100% toluene, on active Al2O3 column, by a new, improved method. Identifications of the basic and the higher fullerenes in chromatographically purified fractions, as well as in the obtained extracts, were performed using determined techniques of IR and UV/VIS spectroscopy that have not been presented previously for the higher fullerenes.
- Published
- 2009
12. Advancement of the Process for Extraction, Chromatography and Characterization of Fullerenes
- Author
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Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Simic-Krstic, J., Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, and Simic-Krstic, J.
- Abstract
In the first phase of this work, the basic C60 and C70 as well as the higher fullerenes, mainly C76 and C84, were Soxhlet extracted with p-xylene and n-heptane from the samples of carbon soot, produced in electrical arc, yielding 5.9% and 0.7% of the extract, respectively. The remaining, p-xylene insoluble soot was then extracted with pyridine, by original advanced method, increasing the entire extract yield for an additional 5.9% to 11.8%. The procedures for increases of the basic and higher fullerenes yields, as well as for additional, selective extraction of the higher fullerenes were found. Chromatographic separation of the basic and the higher C76 and C84 fullerenes from p-xylene extract was performed by continual elution, in one phase of the process, under atmospheric pressure, with original, defined, gradient of solvents from 5% toluene in hexane to pure 100% toluene, on active Al2O3 column, by a new, improved method. Identifications of the basic and the higher fullerenes in chromatographically purified fractions, as well as in the obtained extracts, were performed using determined techniques of IR and UV/VIS spectroscopy that have not been presented previously for the higher fullerenes.
- Published
- 2009
13. Nanoscale magnetic Behavior of C-60 thin films in earth magnetic field under polarization light influences
- Author
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Nikolić, A, Petrov, Ljubiša, Koruga, Đuro, Nikolić, A, Petrov, Ljubiša, and Koruga, Đuro
- Abstract
Magnetic behavior of C-60 thin films in the Earths magnetic field under polarization light influence is presented. Transformation of magnetic field for two fullerene thin films of different thickness is investigated. Two proton magnetometers were used for these measurements. Samples of 30 nm and 250 nm thickness illustrate a significant change of magnetic field intensity under the influence of polarization light. in range from 3.4 to 12.9 nT, for 200 measurement data per sample.
- Published
- 2005
14. Modifications of fullerenes extractions and chromatographies with different solvents
- Author
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Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Simic-Krstic, J, Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, and Simic-Krstic, J
- Abstract
In the Bucky System II, based on electrical arc method, carbon soot was produced. Fullerenes C-60 and C-70 were Soxhlet extracted from the collected soot samples with toluene, chlorobenzene and with both of them successively, modifying the original methods. The yields of the both obtained toluene extracts were 5.4%. Chlorobenzene extract yield was 5.8%. After extraction of toluene insoluble soot with chlorobenzene, the entire extract yield was increased from 5.4% to 5.8%, due to modification of the existing methods. The difference of fullerenes solubilities in these solvents has been concluded. In the second part of our work toluene and chlorobenzene fullerenes extracts were separated by column chromatographics on active Al2O3, modifying the existing methods, by elution with hexane and mixtures of benzene, toluene, or xylene with hexane in determined ratios and orders. Identifications of buckminsterfullerene C-60 in the first chromatographically purified fractions were achieved by electron impact ionization (EI) mass, IR, and UV/VIS spectroscopy. The second and the third purified fullerene fractions, toluene and chlorobenzene soot extracts were characterized by IR and UV/VIS methods.
- Published
- 2003
15. Modifications of fullerenes extractions and chromatographies with different solvents
- Author
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Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, Simic-Krstic, J, Jovanović, Tamara, Koruga, Đuro, Jovančićević, Branimir, and Simic-Krstic, J
- Abstract
In the Bucky System II, based on electrical arc method, carbon soot was produced. Fullerenes C-60 and C-70 were Soxhlet extracted from the collected soot samples with toluene, chlorobenzene and with both of them successively, modifying the original methods. The yields of the both obtained toluene extracts were 5.4%. Chlorobenzene extract yield was 5.8%. After extraction of toluene insoluble soot with chlorobenzene, the entire extract yield was increased from 5.4% to 5.8%, due to modification of the existing methods. The difference of fullerenes solubilities in these solvents has been concluded. In the second part of our work toluene and chlorobenzene fullerenes extracts were separated by column chromatographics on active Al2O3, modifying the existing methods, by elution with hexane and mixtures of benzene, toluene, or xylene with hexane in determined ratios and orders. Identifications of buckminsterfullerene C-60 in the first chromatographically purified fractions were achieved by electron impact ionization (EI) mass, IR, and UV/VIS spectroscopy. The second and the third purified fullerene fractions, toluene and chlorobenzene soot extracts were characterized by IR and UV/VIS methods.
- Published
- 2003
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