9 research outputs found
Nanobubbles at GPa Pressure under Graphene
We provide direct evidence that irradiation of a graphene membrane on Ir with low-energy Ar ions induces formation of solid noble-gas nanobubbles. Their size can be controlled by thermal treatment, reaching tens of nanometers laterally and height of 1.5 nm upon annealing at 1080 \ub0C. Ab initio calculations show that Ar nanobubbles are subject to pressures reaching tens of GPa, their formation being driven by minimization of the energy cost of film distortion and loss of adhesion
EFFECT OF PERIPARTUM DIETARY ENERGY SUPPLEMENTATION ON THYROID HORMONES, INSULIN-LIKE GROWTH FACTOR-I AND ITS BINDING PROTEINS IN EARLY LACTATION DAIRY COWS
only on day 60 after parturition (p<0.01, respectivel
Temperature-Driven Reversible Rippling and Bonding of a Graphene Superlattice
In order to unravel the complex interplay between substrate interactions and film configuration, we investigate and characterize graphene on a support with non-three-fold symmetry, the square Ir(100). Below 500 \ub0C, distinct physisorbed and chemisorbed graphene phases coexist on the surface, respectively characterized by flat and buckled morphology. They organize into alternating domains that extend on mesoscopic lengths, relieving the strain due to the different thermal expansion of film and substrate. The chemisorbed phase exhibits exceptionally large one-dimensional ripples with regular nanometer periodicity and can be reversibly transformed into physisorbed graphene in a temperature-controlled process that involves surprisingly few C\u2013Ir bonds. The formation and rupture of these bonds, rather than ripples or strain, are found to profoundly alter the local electronic structure, changing graphene behavior from semimetal to metallic type. The exploitation of such subtle interfacial changes opens new possibilities for tuning the properties of this unique material
High-energy photoemission in silver: resolving d and sp contributions in valence band spectra
We present high-resolution valence band and core level spectra of silver for
photoelectron kinetic energies up to 8 keV. At these kinetic energies we
estimate a surface contribution of less than 3%. Taking advantage of the
favourable sp/d relative cross-sections, a comparison with the calculated density
of states is presented. We observe an increasing photoemission intensity when
approaching the Fermi level, which we assign to a free-electron-like character
in the 5p-band, whereas the principal s-like contribution is located at the bottom
of the d-band. The difference between measured and calculated values of the
sp/d cross-section ratio is discusse