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281 results on '"Ceccone, G."'

59. MoS2 nano-particle production in a PACVD environment

Author

Stoffels - Adamowicz, E., Stoffels, W.W., Ceccone, G., Rossi, F., Hasnaoui, R., Keune, H., Wahl, G., Pisarczyk, P., Pisarczyk, T., Wolowski, J., Orthopaedic Biomechanics, and Elementary Processes in Gas Discharges

Published
1999

60. Physico-chemical characterization and cell behavior influence of surfaces modified by enzymatically-tailored pectic hairy polysaccharides

Author

Ceccone, G., Gilliland, D., Liakos, I., Cascardo, G., Cassinelli, C., Morra, M., Della Volpe, C., Rodriguez-Valverde, M., Siboni, S., Ischia, G., Segatta, G., Verhoef, R., Schols, W., Jorgensen, B., Ulvskov, P., Nagel, M. D., Ceccone, G., Gilliland, D., Liakos, I., Cascardo, G., Cassinelli, C., Morra, M., Della Volpe, C., Rodriguez-Valverde, M., Siboni, S., Ischia, G., Segatta, G., Verhoef, R., Schols, W., Jorgensen, B., Ulvskov, P., and Nagel, M. D.

Published
2008

80. MoS2 nanoparticle formation in a low pressure environment

Author

Stoffels - Adamowicz, E., Stoffels, W.W., Ceccone, G., Hasnaoui, R., Keune, H., Wahl, G., Rossi, F., Stoffels - Adamowicz, E., Stoffels, W.W., Ceccone, G., Hasnaoui, R., Keune, H., Wahl, G., and Rossi, F.

Abstract

Formation of MoS2 nanoparticles at pressures between 0.5 and 10 Torr has been studied. Two different chemistries for the particle nucleation are compared: one based on MoCl5 and H2S, and the other based on MoCl5 and S. In both cases particle formation has been studied in a thermal oven and in a radio-frequency discharge. Typically, the reaction rates at low pressures are too low for an efficient thermal particle production. At pressures below 10 Torr no particle production in the oven is achieved in H2S chemistry. In the more reactive chemistry based on sulfur, the optimal conditions for thermal particle growth are found at 10 Torr and low gas flows, using excess of hydrogen. In the radio-frequency discharge, nanoparticles are readily formed in both chemistries at 0.5 Torr and can be detected in situ by laser light scattering. In the H2S chemistry particles smaller than 100 nm diameter have been synthesized, the sulfur chemistry yields somewhat larger grains. Both in thermal and plasma-enhanced particle syntheses, using excess of hydrogen is beneficial for the stability and purity of the particles.

Published
1999

81. Laser-induced particle formation and coalescence in a methane discharge

Author

Stoffels, W.W., Stoffels - Adamowicz, E., Ceccone, G., Rossi, F., Stoffels, W.W., Stoffels - Adamowicz, E., Ceccone, G., and Rossi, F.

Abstract

Laser-induced formation of submicrometer dust particles and the subsequent coalescence phenomena in a low-pressure methane radio-frequency plasma have been analyzed. Six distinct phases can be distinguished: (a) nanoparticle synthesis by laser interaction with the plasma species, (b) particle conglomeration and the formation of ordered Coulomb lattices at the plasma–sheath region above the powered electrode, (c) coalescence of grains within the Coulomb lattice and formation of submillimeter strings, (d) condensation of the strings in the discharge and the formation of V-shaped structures, (e) condensation of the V structures into a single network of several centimeters in diameter suspended in the plasma, (f) deposition of the network on the electrode and its subsequent growth on the surface. Large carbon structures as well as nanoparticles have been analyzed in situ by He–Ne laser light scattering and laser ablation and ex situ by an optical and a scanning electron microscope, and by micro-Raman spectroscopy. © 1999 American Vacuum Society.

Published
1999

86. The brazing of Si3N4 with Ni-Cr-Si alloys

Author

Ceccone, G., Nicholas, M.G., Peteves, S.D., Kodentsov, A., Kivilahti, J., Loo, van, F.J.J., Ceccone, G., Nicholas, M.G., Peteves, S.D., Kodentsov, A., Kivilahti, J., and Loo, van, F.J.J.

Abstract

The use of commercially available and laboratory made Ni-Si-Cr brazes for wetting and bonding Si3N4 has been explored. The microstructure and chemistry of brazed joints has been characterized by techniques such as optical microscopy, scanning electron microscopy, electron probe micro-analysis and X-ray diffraction. Si3N4 was wetted well by all the braze alloys at 1150–1200 °C, but the joint quality obtained was poor because of the formation of brittle phases and solid solutions.

Published
1995

89. MoS2 nanoparticle formation in a low pressure environment

Author

Stoffels, E., Stoffels, W.W., Ceccone, G., Hasnaoui, R., Keune, H., Wahl, G., and Rossi, F.

Subjects
Molybdenum disulfide -- Research, Nucleation -- Research, Particles (Nuclear physics) -- Research, Physics
Abstract

Research was conducted to examine the formation of MoS2 nanoparticles at pressures between O.5 and 10 Torr. A comparison of two different chemistries for the particle nucleation, namely, one based on H2S and MoCl5 and the other based on MoCl5 and S, was performed. Results demonstrate that the use of excess hydrogen in both the thermal and plasma-enhanced particle syntheses is advantageous for the purity and stability of the particles.

Published
1999

96. Surface characterisation of PEO-like microstructures by means of ToF-SIMS, XPS and SPR.

Author

Perez ‐ Roldan, M., Colpo, P., Gilliland, D., Ceccone, G., and Rossi, F.

Abstract

In this work, we present a method to produce micro and nanostructured surfaces containing bioadhesive features embedded in an antifouling matrix. These surfaces are fabricated by combining plasma polymerization and electron beam lithography. This combination allows the fabrication of structured surfaces in just two steps and without the use of solvents. ToF-SIMS analysis demonstrates that the e-beam treatment induces a chemical change at the surface depending upon the radiation dose employed. In particular, a decrease of peaks characteristic of the PEO-like fragments (e.g. CH3O+, C3H7O+, C3H5O2+) and a correspondent increase of hydrocarbon moieties such as C2H3+ and C3H3+ is observed in the irradiated zones. These results are supported by XPS analysis that indicate a slight reduction of the intensity of the C-O component in the C1s core level spectrum after irradiation similar to that observed in UV-treated PEO-like films. Experiments with proteins show a preferential adhesion of the biomolecules to the irradiated zone indicating the good potential of this technique for the development of nanostructured biosensing platforms. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Published
2013
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99. Ion beam sputtering of Ta2O5 films on thermoplast substrates as waveguides for biosensors.

Author

Kulisch, W., Gilliland, D., Ceccone, G., Sirghi, L., Rauscher, H., Gibson, P. N., Zürn, M., Bretagnol, F., and Rossi, F.

Subjects
TANTALUM oxide, THIN films, SPUTTERING (Physics), SURFACES (Technology), ION-surface impact, ELLIPSOMETRY, DIELECTRIC measurements
Abstract

Tantalum pentoxide thin films have been deposited at room temperature by (dual) ion beam sputtering for applications as waveguides in biosensors. The oxygen partial pressure and the energy of the substrate ion beam were the major parameters varied in ion beam sputtering and dual ion beam sputtering experiments, respectively. For sufficiently high oxygen partial pressures, the films were stoichiometric, free of contaminants, amorphous, and extremely smooth. Ion bombardment of the growing films with Ar+ ions up to 200 eV had no significant influence on these properties. The refractive index of stoichiometric films was 2.1±0.1 and the extinction coefficient well below the resolution limit of ellipsometry and UV/visible measurements. By coupling a laser beam via an optical grating into a 150 nm thick Ta2O5 layer, the optical losses could be estimated to be below 3 dB/cm. A series of experiments has been carried out to prove that this deposition process is compatible with the use of thermoplast substrates which are sensitive not only to high temperatures but also to ion bombardment and UV radiation. Finally, first experiments are presented to functionalize the surfaces of Ta2O5 films with amine and epoxy groups. [ABSTRACT FROM AUTHOR]

Published
2009
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