Giannazzo F.,CNR Institute for Microelectronics and Microsystems |
Deretzis I.,CNR Institute for Microelectronics and Microsystems |
La Magna A.,CNR Institute for Microelectronics and Microsystems |
Franco S.D.,CNR Institute for Microelectronics and Microsystems |
And 6 more authors.
Materials Science Forum | Year: 2013
Two dimensional maps of the electronic conductance in epitaxial graphene (EG) grown on SiC were obtained by conductive atomic force microscopy (CAFM). The correlation between morphological and electrical maps revealed the local conductance degradation in EG over the SiC substrate steps or at the junction between monolayer (1L) and bilayer (2L) graphene regions. The effect of steps strongly depends on the charge transfer phenomena between the step sidewall and graphene, whereas the resistance increase at 1L/2L junction is a purely quantum mechanical effect, due to the weak coupling between 1L and 2L electron wavefunctions. © (2013) Trans Tech Publications, Switzerland.
Ratti C.,University of Turin |
Bellwied R.,University of Houston |
Cristoforetti M.,ETC |
Barbaro M.,University of Turin
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012
Recent lattice QCD calculations, at physical pion masses and small lattice spacings that approach the continuum limit, have revealed that nondiagonal quark correlators above the critical temperature are finite up to about 2 T c. Since the transition from hadronic to free partonic degrees of freedom is merely an analytic crossover, it is likely that, in the temperature regime between 1-2 Tc, quark and gluon quasiparticles and prehadronic bound states can coexist. The correlator values, in comparison to Polyakov loop-extended Nambu-Jona-Lasinio model calculations beyond mean field, indicate that at least part of the mixed phase resides in color-neutral bound states. A similar effect was postulated for the in-medium fragmentation process, i.e. for partons which do not thermalize with the system and thus constitute the nonequilibrium component of the particle emission spectrum from a deconfined plasma phase. Here, for the first time we investigate the likelihood of forming bound states also in the equilibrated, parton-dominated phase above T c which is described by lattice QCD. © 2012 American Physical Society.
Rikard Gebart B.,ETC |
Rikard Gebart B.,Lulea University of Technology |
Wiinikka H.,ETC |
Marklund M.,ETC |
And 5 more authors.
Cellulose Chemistry and Technology | Year: 2011
Pressurized oxygen blown black liquor gasification, a new process for the recovery of energy and spent chemicals from chemical pulp mills, enables efficient power production or the production of motor fuels. In this paper, the experimental results of a 3 MWth, process development plant are presented and compared with the results of a CFD model. The key parameters with the largest effect on gas composition are: operating pressure, oxygen-to-fuel equivalence ratio, black liquor load and black liquor preheating temperature. The experimental gas composition during normal operation of the gasifier does not agree with equilibrium calculations. However, the agreement for the main components (CO, CO2 and H2) becomes very good if the CH4 and H2S concentrations are prescribed in the equilibrium code. The impurities present in the syngas were also investigated, the observation being made that the particle content in the gas after cooling was very low, and the only significant trace elements were Cl and N. A theoretical model for the gasifier has been implemented in the commercial CFD code Ansys-CFX. The results of the code agree well with the experiments for the major components in the gas, while the CH4concentration is under-predicted. A separate analysis with an equilibrium code (Factsage) shows that the CH4 content at equilibrium, under experimental conditions is very low, which agrees with the CFD code but disagrees with the experiments. The reason for the disagreement between the experiments and the theoretical models is assumed to be the limiting kinetics for CH4 conversion. A first approximation of the kinetics was implemented in the CFD code, which resulted in a very good agreement with the experiments.
La Via F.,CNR Institute for Microelectronics and Microsystems |
Camarda M.,CNR Institute for Microelectronics and Microsystems |
Canino A.,CNR Institute for Microelectronics and Microsystems |
Severino A.,CNR Institute for Microelectronics and Microsystems |
And 4 more authors.
Materials Science Forum | Year: 2013
In this paper the epitaxial process with chloride precursors has been described. In particular it has been shown that the growth rate can be increased to about 100 μm/h but higher growth rate can be difficult to reach due to the limited surface diffusion at the usual temperature of SiC epitaxy. This process gives several advantages because it gives the opportunity to increase the throughput and consequently to reduce the cost of epitaxy, using new reactor structures, and to reduce several kind of defects (Basal Plane Dislocations, Stacking Faults, Threading Dislocations) and to decrease the surface roughness at the same time. © (2013) Trans Tech Publications, Switzerland.
Agency: National Aeronautics and Space Administration | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 42.78K | Year: 1987
THE SCANNING ELECTRON MICROSCOPE (SEM) COMBINED WITH AN ENERGY DISPERSIVE X-RAY ANALYZER (EDX) IS IDEAL FOR CHARACTERIZING THE SIZE, COMPOSITION, AND MORPHOLOGY OF PARTICULATE MATTER. THIS TECHNOLOGY IS OFTEN LIMITED, HOWEVER, BY THE INABILITY TO COLLECT DATA ON STATISTICALLY SIGNIFICANT PARTICLE POPULATIONS. AS A RESULT, MUCH OF THE MICROSCOPIC WORK PERFORMED TO DATE HAS BEEN QUALITATIVE RATHER THAN QUANTITATIVE. HOWEVER, RECENT ADVANCES IN COMPUTER CONTROL AND DATA PROCESSING TECHNIQUES ARE RAPIDLY CHANGING THE VERY NATURE OF MICROSCOPIC ANALYSES. TODAY, COMPUTER CONTROLLED SCANNING ELECTRON MICROSCOPY (CCSEM) AND AUTOMATIC IMAGE ANALYSIS PERMIT QUANTIFICATION OF ATMOSPHERIC AEROSOLS AND SUBTLE DIFFERENCES IN THE SIZE, SHAPE, AND COMPOSITION OF ATMOSPHERIC AEROSOLS. COUPLING THIS RAPIDLY EMERGING TECHNOLOGY WITH CLUSTER ANALYSIS, A MATHEMATICAL TECHNIQUE FOR IDENTIFYING COMMONALITY IN OBJECTS OR GROUPS OF OBJECTS, AND FRACTAL ANALYSIS, A MATHEMATICAL TECHNIQUE WHICH PERMITS DETAILED QUANTIFICATION OF SURFACE TEXTURE COMPARABLE TO THE DETAIL PERCEIVED BY THE HUMAN EYE, SHOULD PERMIT QUANTIFICATION OF PARTICULATE MATTER IN A MANNER NEVER BEFORE PERFORMED. THIS PROPOSED PROJECT INTENDS TO DEMONSTRATE THE FEASIBILITY OF USING A NOVEL COMBINATION OF CCSEM, CLUSTER ANALYSIS AND FRACTAL ANALYSIS TECHNIQUES TO CHARACTERIZE ATMOSPHERIC AEROSOLS.