Search results for "Phase Transition"

Optimized Deposition of Graphene Oxide Langmuir-Blodgett Thin Films

2014

Abstract Single sheet graphene (SG) is an innovative transparent material with high electrical and thermal conduction the use of which in transparent electrodes instead of traditional materials improves the performance of optoelectronic devices. In this study, graphene oxide (GO) has been obtained by a modified Hummer`s method followed by an advanced technique of water removal (lyophilisation). The Langmuir-Blodgett (LB) method was applied to transfer GO from suspension to substrate. To optimize the deposition process, as suspending and spreading solvents the benzene and benzene/methanol mixtures were chosen instead of previously studied water suspensions. The number of GO layers in suspens…

Study of phase transition in Bi3TiNbO9-BaBi2Nb2O9 ceramics

2016

Abstract The subject of the paper is lead free bismuth layer structure oxides (1-x)Bi3TiNbO9-xBaBi2Nb2O9 (x=0; 1; 2; 3 mol). The influence of Bi3TiNbO9/BaBi2Nb2O9 ratio on dielectric and structural properties was studied in a wide range of temperatures. Change in the ratio causes a decrease in the maximum value of dielectric permittivity and shifts the temperature of ε’max to low values, leading to linear decreasing of average grain size and linear increasing of ceramics density. These results indicate an augment of the packing degree and the participation of pores are significantly decreased with the increase of BaBi2Nb2O9 compound intake. Moreover, for 0.7Bi3TiNbO9-0.3BaBi2Nb2O9 ceramics …

Experimental evidence for a liquid-liquid crossover in deeply cooled confined water.

2014

International audience; In this work we investigate, by means of elastic neutron scattering, the pressure dependence of mean square displacements (MSD) of hydrogen atoms of deeply cooled water confined in the pores of a three-dimensional disordered SiO 2 xerogel; experiments have been performed at 250 and 210 K from atmospheric pressure to 1200 bar. The " pressure anomaly " of supercooled water (i.e., a mean square displacement increase with increasing pressure) is observed in our sample at both temperatures; however, contrary to previous simulation results and to the experimental trend observed in bulk water, the pressure effect is smaller at lower (210 K) than at higher (250 K) temperatur…

Pb-PbOHCl Composite Nanowires Synthesized by Galvanic Deposition in Template

2019

In this paper, we report a detailed study on the synthesis of composite nanowires of Pb-PbOHCl via galvanic deposition into the pores of a membrane acting as a template. PbOHCl deposition quantitatively occurs as the solution pH exceeds the value of about 4.12. Simultaneously, owing to the galvanic coupling, electro-deposition of lead occurs, so composite nanowires were formed. The role of different parameters controlling the kinetic evolution of the process, such as oxygen bubbling, solution pH, surface area and type of sacrificial anode were investigated one at a time. The results suggest that every modification accelerating the alkalization of the solution inside the template pores favor…

The micro-macro link in understanding sport tactical behaviours: Integrating information and action at different levels of system analysis in sport

2015

Les liens micro-macroscopiques sont centraux dans les sciences du mouvement humain dans la mesure ou ils correspondent aux coordinations et aux echelonnages des comportements moteurs a differents niveaux d’analyse des systemes complexes. Cet aspect de la complexite est un point cle permettant de considerer decision et action comme un comportement de transition a differents niveaux lors de la realisation d’une performance. Les transitions exprimees en termes de bifurcations sont une part importante du mecanisme universel de decision. Les transitions de phase fournissent aussi un moyen de comprendre les liens micro-macro. Dans cet article de synthese, nous developpons un point de vue qui expl…

The micro-macro link in understanding sport tactical behaviours: Integrating information and action at different levels of system analysis in sport

2015

The micro-macro link is a central issue of human movement sciences because it directly refers to coordination and scalability of movement behaviour at different levels of analysis in a complex system. This feature of complexity is a key feature to consider decisions and actions as transitional behaviours at different levels during performance. Transitions expressed through bifurcations are an important part of a universal decisionmaking process. Here we explain how individuals perform decision-making behaviours in a minimal social performance unit ( competing dyads), and how these two levels are linked in a sports team. Finally we discuss some applications of the micro-macro links for the d…

Characterization of the pressure induced Ringwoodite to Mg-perovskite+Mg-wuestite phase transition by Catastrophe Theory

2010

A first-order phase transition for pulsar surface

2012

In this paper, we explain the existence of a possible first-order phase transition that may occur over the external solid crust of a pulsar, by means of an interpretation of a particular formal model (drawn from Theoretical Astrophysics) whose thermodynamical phenomenology shows a possible first-order phase transition (according to Landau’s Phenomenological Theory).

Preparation, crystal structure at 298 and 90 K and phase transition in (C2H5NH3) 2[SbBr5] studied by the single crystal X-Ray diffraction method

2004

The reaction of antimony(III) oxide with ethylamine, in molar ratios from 1:1 to 1:10, in concentrated hydrobromic acid leads to the formation of one product – bis(ethylammonium) pentabromoantimonate(III). The structure of (C2H5NH3)2[SbBr5] was determined at 298 and 90 K, below and above the phase transition that occurs at about 158.5 K. The orthorhombic system was found in both phases, space groups Cmca and Pbca at 298 and 90 K, respectively. At both temperatures the structure consists of [SbBr6] 3− octahedra connected via cis bromine atoms forming one-dimensional zig-zag [{SbBr5}2−]n chains. The ethylammonium cations fill the space between polyanionic chains. The organic and inorganic sub…

Aluminum tri-isopropoxide as an alternative precursor for atomic layer deposition of aluminum oxide thin films

2019

Due to the safety challenges associated with the use of trimethylaluminum as a metal precursor for the deposition of alumina, different chemicals have been investigated over the years to replace it. The authors have investigated the use of aluminum tri-isopropoxide (TIPA) as an alternative alkoxide precursor for the safe and cost-effective deposition of alumina. In this work, TIPA is used as a stable Al source for atomic layer deposition (ALD) of Al2O3 when different oxidizing agents including water, oxygen plasma, water plasma, and ozone are employed. The authors have explored the deposition of Al2O3 using TIPA in ALD systems operating in vacuum and atmospheric pressure conditions. For the…