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618 results on '"Pelosi, C."'

151. In-depth analysis of the interfaces in InGaAs/InGaP heterosystem

Author

Pelosi C., Attolini G., Frigeri C., Bersani M., Giubertoni D., Vanzetti L., and Kudela R.

Subjects
MOVPE, GaAs, TEM, InGaP
Abstract

Different GaAs-matched epitaxial structures based on InGaP and InGaAlP layers were prepared by LP MOVPE. The suitable p- and n-type sequence of these layers will be used as active elements in high efficiency solar cells. The layers were grown on (001) GaAs substratesoriented 2° off towards (110) using trimethylgallium (TMG),trimethylaluminium (TMA), trimethylindium (TMI), arsine (AsH3) and phosphine (PH3) as main reagents and dimethylzinc (DMZ) and silane (SiH4) as p- and n-type doping reagents, respectively.The layers have been analyzed as regards their compositional homogeneity, interface abruptness and doping concentration by different techniques such as SIMS, TEM and AFM.The combined analysis of SIMS and TEM has been of great usefulness in order to define the abruptness of composition change. Moreover an analysis of autodoping effects is reported as regards the arsenic diffusion in InGaP matrix and the analysis of different samples is reported.

Published
2004

157. Aspetti generali della crescita epitassiale MOCVD

Author

Regonini D., Attolini G., Pelosi C., Watts B. E., Melioli E., and Leccabue

Abstract

In the present work a short general view of MOCVD epitaxial growth has been reported, but most considerations can be extended to others CVD systems. In the section on gas handling systems, mass flow and pressure controllers, valves and filters, that are necessary to achieve reproducibility and good performances in a CVD plant, are described. Properties of metallorganic precursors, different type of reactors and various heating systems are discussed to introduce the guidelines of our project concerning the realization of a MOCVD reactor for silicon carbide epitaxial growth. At the end, a briefly description of the Programmable Logic Controller (PLC), usually employed to automate the various CVD operations, has been also reported.

Published
2003

163. Zn1-xMnxGa2Se4: a new series of magnetic dilated semiconductors

Author

Morón, M. Carmen, Campo, Javier, Stankiewicz, Jolanta, Palacio, Fernando, Attolini, G., and Pelosi, C.

Abstract

Trabajo presentado a la 7th European Magnetic Materials and Applications Conference (EMMA), celebrada en España en septiembre de 1998.

Published
1998

165. Helicobacter PyloriHP(2–20) Induces Eosinophil Activation and Accumulation in Superficial Gastric Mucosa and Stimulates VEGF-α and TGF-β Release by Interacting with Formyl-Peptide Receptors

Author

Prevete, N., primary, Rossi, F.W., additional, Rivellese, F., additional, Lamacchia, D., additional, Pelosi, C., additional, Lobasso, A., additional, Necchi, V., additional, Solcia, E., additional, Fiocca, R., additional, Ceppa, P., additional, Staibano, S., additional, Mascolo, M., additional, D'Argenio, G., additional, Romano, M., additional, Ricci, V., additional, Marone, G., additional, and De Paulis, A., additional

Published
2013
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170. Micro-Raman And Micro-Stratigraphic Analysis Of The Painting Materials In The Rock-Hewn Church Of The Forty Martyrs In Şahinefendi, Cappadocia (Turkey).

Author

Pelosi, C., Agresti, G., Andaloro, M., Baraldi, P., Pogliani, P., Santamaria, U., La Russa, M. F., Ruffolo, S. A., and Rovella, N.

Subjects
*STRATIGRAPHIC archaeology, *PAINTING, *WORLD Heritage Sites, *SCANNING electron microscopy, *MIDDLE Ages
Abstract

This paper presents the results of analyses carried out on the paintings on the rock-hewn walls of the Forty Martyrs church at Şahinefendi in Cappadocia (a UNESCO World Heritage Site), a central region of Turkey, performed during conservation work from 2007 to 2012. The micro-samples were investigated by spectroscopic, micro-stratigraphic and scanning electron microscopy analysis in order to study the painting technique, the materials and the degradation products. The micro-stratigraphic analysis showed a white, sometimes pinkish, plaster. Micro-Raman analysis, performed on cross-sections of the mortars, enabled the detection of calcite, gypsum, anhydrite and calcium oxalate. Scanning electron microscopy and energy-dispersive spectroscopy revealed a similar composition among all investigated phases, aside from minor differences such as the presence of diatoms in the second and third phases and of biotite, lime lumps and plants fragments in the fourth one. Apart from traditional pigments of medieval wall paintings, micro-Raman analysis revealed the presence of lead-based compounds and jarosite. [ABSTRACT FROM AUTHOR]

Published
2016
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171. Sublethal effects of epoxiconazole on the earthworm Aporrectodea icterica.

Author

Pelosi, C., Lebrun, M., Beaumelle, L., Cheviron, N., Delarue, G., and Nélieu, S.

Subjects
EARTHWORMS, APORRECTODEA, AGRICULTURAL ecology, SOIL remediation, PHYTOREMEDIATION
Abstract

Earthworms play a key role in agroecosystem soil processes. This study aims to assess the effects of different doses of a commercial formulation of epoxiconazole (Opus®), a persistent and widely used fungicide, on the earthworm Aporrectodea icterica. A laboratory study was conducted in a natural soil in order to measure effects of Opus® on earthworm mortality, uptake, weight gain, enzymatic activities (catalase and glutathione-S-transferase), and energy resources (lipids and glycogens). The estimated LC50 was 45.5 mg kg, or 268 times the recommended dose. Weight gains were 28, 19, and 13 % of the initial weight after 28 days of exposure in the control and D1 and D10 (1 and 10 times the recommended dose) treatments, respectively. No difference was observed for catalase activity between the three treatments, at 7, 14, or 28 days. The glutathion-S-transferase (GST) activity was two times as high in D1 as in D0 at 14 days. At 28 days, glycogen concentration was lower in D10 than in the D1 treatment. This study highlighted moderate sublethal effects of the commercial formulation Opus® for earthworms. Considering that these effects were observed on a species found in cultivated fields, even at recommended rates, much more attention should be paid to this pesticide. [ABSTRACT FROM AUTHOR]

Published
2016
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172. Evaluation of epoxiconazole bioavailability in soil to the earthworm Aporrectodea icterica.

Author

Nélieu, S., Delarue, G., Ollivier, E., Awad, P., Fraillon, F., and Pelosi, C.

Subjects
BIOAVAILABILITY, TRIAZOLES, HUMUS, SOIL texture, CYCLODEXTRINS
Abstract

In soil, the determination of total concentration using an exhaustive extraction method has little relevance to evaluate the exposure of an organism to a chemical, because of sorption processes. This study aims to propose a mild extraction method to evaluate the bioavailability of the fungicide epoxiconazole to the earthworm Aporrectodea icterica. Experiments were conducted in soils presenting various textures and organic carbon contents, spiked with formulated epoxiconazole 7 to 56 days prior to their extraction. In parallel, the epoxiconazole concentration was determined in exposed earthworms and the fungicide's effects were evaluated by measuring weight gain, enzymatic activities and total protein contents. Among the various mild chemical solvents tested to evaluate the environmental availability of the fungicide, the 50 mM hydroxypropyl-β-cyclodextrin solution allowed to extract around 30 % of epoxiconazole. This percentage corresponded to the ratio determined in exposed A. icterica under similar soil conditions. Furthermore, this mild method was demonstrated to be sensitive to soil sorption capacities and to ageing. The mild extraction method was then applied to explore the relationship between total and (bio)available concentrations in soil and in A. icterica, over 7- or 28-day exposure time. This demonstrated the proportionality between epoxiconazole concentration in earthworm and available in soil (up to 96 %, with regression coefficient R = 0.98). Sublethal effects on earthworm remained not significant. [ABSTRACT FROM AUTHOR]

Published
2016
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179. Raman and Photoluminescence Mapping of Lattice Matched InGaP/GaAs Heterostructures

Author

VALLADOLID UNIV (SPAIN) SISICA DE LA MATERIA CONVENSADA, Attolini, G., Fallini, P., Germini, F., Pelosi, C., Martinez, O., VALLADOLID UNIV (SPAIN) SISICA DE LA MATERIA CONVENSADA, Attolini, G., Fallini, P., Germini, F., Pelosi, C., and Martinez, O.

Abstract

The influence of the substrate on composition and CuPt-type spontaneous order of MOVPE lattice matched InGaP/GaAs layers was studied. The study was carried out by microRaman and microphotoluminescence. The order was determined by the band gap, while the Raman parameters were also contributed by the surface topography that was also related to the type of substrate. The spontaneous order increases with Si-doping of the substrates. Doping the layers with Zn randomises the alloy., Pub in: Materials Research Society Symposium Proceedings, Volume 692. This article is from ADA405047 Progress in Semiconductor Materials for Optoelectronic Applications Symposium held in Boston, Massachusetts on November 26-29, 2001.

Published
2002

188. Zn1-xMnxGa2Se4: A new series of diluted magnetic semiconductors

Author

Caja de Ahorros de la Inmaculada de Aragón, Comisión Interministerial de Ciencia y Tecnología, CICYT (España), Diputación General de Aragón, Morón, M. Carmen, Campo, Javier, Palacio, Fernando, Attolini, G., Pelosi, C., Caja de Ahorros de la Inmaculada de Aragón, Comisión Interministerial de Ciencia y Tecnología, CICYT (España), Diputación General de Aragón, Morón, M. Carmen, Campo, Javier, Palacio, Fernando, Attolini, G., and Pelosi, C.

Abstract

The magnetic properties of a new series of diluted magnetic semiconductors Zn1-xMnxGa2Se4 with x ranging between 0 and 1 are reported from magnetization and AC magnetic susceptibility data. Antiferromagnetic as well as spin-glass-like behaviors have been detected showing a dependence with the Mn content as well as the cation distribution.

Published
1999

196. Thermodynamic study of interface between InGaP/GaAs and GaAs/InGaP heterosystems

Author

Pelosi, C., Bosi, M., Attolini, G., Prutskij, T., Pelosi, C., Bosi, M., Attolini, G., and Prutskij, T.

Abstract

The issue regarding the interfaces between arsenide and phosphide in III-V semiconductor is particularly relevant for Vapour Phase Epitaxy (VPE) and Metallo-Organic Vapour Phase Epitaxy (MOVPE) techniques; an irreproducibility in preparing abrupt interfaces between arsenide and phosphide has been evidenced by several authors and is often imputed to the volatility of arsenic and phosphorus species: Many different growth procedures have been suggested in order to obtain sharp transition between the two different materials.
A novel approach to this problem is addressed in this work, in which the substrate/film interface is modelled using thermodynamical calculations after the “regular solution”. InGaP samples were grown on GaAs substrate by MOVPE technique and characterised by photoluminenescence (PL) and Transmission Electron Microscopy (TEM) in order to support the theoretical model.

Published
2006
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197. The properties of GaInP/GaAs heterostructures as a function of growth temperature

Author

Pelosi, C., Attolini, G., Bosi, M., Martín, E., Martinez, O., Sanz, L. F., Jiménez, J., Prutskij, T., Pelosi, C., Attolini, G., Bosi, M., Martín, E., Martinez, O., Sanz, L. F., Jiménez, J., and Prutskij, T.

Abstract

In order to find the best conditions under which ordering process is reduced InGaP layers were grown on GaAs substrates by Metal Organic Vapor Phase Epitaxy (MOVPE) at low pressure in the temperature range between 525 and 600 °C. Because the metal organic cracking process was affected by temperature change the ratio between metal organic TriMethyl Gallium (TMG) and TriMethyl Indium (TMI) has to be tuned for every temperature, while maintaining the same reduced pressure of 60 mbar. The growth rate and the gaseous TMG/TMI ratio giving the match to GaAs are reported as a function of the growth temperature. Cathodoluminescence (CL) and μ-Raman analysis were used to understand the contributions of composition fluctuations, strain, Cu-Pt type ordering on the properties of the layers.

Published
2006
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198. Polarized photoluminescence of the of GaInP2layers grown on GaAs and Ge substrates by MOVPE technique

Author

Prutskij, T., Pelosi, C., Brito-Orta, R., Prutskij, T., Pelosi, C., and Brito-Orta, R.

Abstract

Photoluminescent properties of GaInP2films grown by metal-organic vapor phase epitaxy (MOVPE) on two different substrates (GaAs and Ge) are studied. The grown GaInP2films were nearly lattice matched to GaAs, had the same thickness of approximately 0.5 μm and different values of ordering parameter. Photoluminescence (PL) measurements were performed in a wide temperature range (10 – 300 K) for polarization of the emitted radiation along the [011] and [ 0$\overline 1 $1] directions. The temperature dependence of the photoluminescence intensity ratio for two polarizations was calculated and found experimentally. To estimate the value of the energy separation between the heavy-hole and light–hole bands a simulation of the spectra was realized using parabolic bands and Boltzmann statistics.

Published
2006
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