Investigating the longitudinal optical conductivity of graphene systems, which is the mostimportant property for opto-electronic devices, for three-layer graphene systems theoretically and numerically is the main purpose of this study. Each layer can be mono- or bi-layer graphene. Separation between layers has been denoted by d, selected to be about ten nanometers. The carrier densities i...

The longitudinal optical conductivity is the most important property for graphene-baseddevices. So investigating this property for spatially separated few-layer graphene systems analytically and numerically is the main purpose of our study. Each layer can be mono- or bi-layer graphene. The density-density correlation function has been screened by the dielectric function using the random p...

in this study ptfeco ternary alloys nanoparticles of three dimentional (3d) rhombus shapes dispersed on graphene nanosheets (ptfeco/gr) were successfully prepared and studied as electrocatalysts for oxygen reduction reaction (orr) in polymer-electrolyte fuel cells. a combination of analytical techniques including powder x-ray diffraction, x-ray photoelectron spectra, inductively coupled plasma-...

this paper presents the thermal vibration analysis of double-layer graphene sheet embedded in polymer elastic medium, using the plate theory and nonlocal continuum mechanics for small scale effects. the graphene is modeled based on continuum plate theory and the axial stress caused by the thermal effects is also considered. nonlocal governing equations of motion for this double-layer graphene s...

Graphene membranes have the potential to exceed the permeance and selectivity limits of conventional gas separation membranes. Realizing this potential in practical systems relies on overcoming numerous scalability challenges, such as isolating or sealing permeable defects in macroscopic areas of graphene that can compromise performance and developing methods to create high densities of selecti...

this paper discusses the use of box behnken design (bbd) approach to plan the experiments for turning the yield of cvd, thickness and layer number of graphene sheets with an overall objective of optimizing the process to provide higher graphene production volume, fewer layers and thinness structure of graphene. bbd is having the maximum efficiency for an experiment involving four factors such a...

In this study PtFeCo ternary alloys nanoparticles of three dimentional (3D) rhombus shapes dispersed on graphene nanosheets (PtFeCo/Gr) were successfully prepared and studied as electrocatalysts for oxygen reduction reaction (ORR) in polymer-electrolyte fuel cells. A combination of analytical techniques including powder X-ray diffraction, X-ray photoelectron spectra, inductively coupled plasma-...

We use atomic force microscopy to in situ investigate the dynamic behavior of confined water at the interface between graphene and mica. The graphene is either uncharged, negatively charged, or positively charged. At high humidity, a third water layer will intercalate between graphene and mica. When graphene is negatively charged, the interface fills faster with a complete three layer water fil...

graphene-based nanocomposites are newly emerged materials with a wide range of applications such as in supercapacitors electrode. the high conductivity and ability for passing electric current, makes graphene an appropriate new item to be used in cells. electroactive transition metal oxides, owing fast reversible redox pairs, are used to store electrical charge. furthermore, the graphene/nio na...

A strong substrate-graphite bond is found in the first all-carbon layer by density functional theory calculations and x-ray diffraction for few graphene layers grown epitaxially on SiC. This first layer is devoid of graphene electronic properties and acts as a buffer layer. The graphene nature of the film is recovered by the second carbon layer grown on both the (0001) and (0001[over]) 4H-SiC s...