Influence of growing conditions on the reactivity of Ni supported graphene towards CO

Free standing graphene is chemically inert but, as recently demonstrated, CO chemisorption occurs at low crystal temperature on the single layer grown by ethene dehydrogenation on Ni(111). Such layer is inhomogeneous since different phases coexist, the relative abundance of which depends on the growth conditions. Here we show by X ray photoemission and high resolution electron energy loss spectroscopies that the attained CO coverage depends strongly on the relative weight of the different phases as well as on the concentration of carbon in the Ni subsurface region. Our data show that the chemical reactivity is hampered by the carbon content in the substrate. The correlation between the amount of adsorbed CO and the weight of the different graphene phases indicates that the top-fcc configuration is the most reactive

A full conformational characterization of antiandrogen cortexolone- 17α-propionate and related compounds through theoretical calculations and nuclear magnetic resonance spectroscopy

Cortexolone-17\u3b1-propionate is a topical antiandrogen under investigation for the treatment of androgen-related skin disorders. A full conformational characterization was realized, in comparison with other steroidal androgens and antiandrogens, by means of theoretical calculations at the B3LYP/6-31G(d) level supported by high-field NMR analyses. All of the studied molecules showed a good overlay; nevertheless, the different functional groups present in the skeleton of the molecules drive the individual biological profile. \ua9 2014 the Partner Organisations

Domain wall dynamics and Barkhausen effect in metallic ferromagnetic materials. I. Theory

The Barkhausen effect (BE) in metallic ferromagnetic systems is theoretically investigated by a Langevin description of the stochastic motion of a domain wall in a randomly perturbed medium. BE statistical properties are calculated from approximate analytical solutions of the Fokker-Planck equation associated with the Langevin model, and from computer simulations of domain‐wall motion. It is predicted that the amplitude probability distribution P0(Φ) of the B flux rate Φ should obey the equation P0(Φ)∝Φ−1 exp(−Φ/〈Φ〉), with >0. This result implies scaling properties in the intermittent behavior of BE at low magnetization rates, which are described in terms of a fractal structure of fractal dimension D<1. Analytical expressions for the B power spectrum are also derived. Finally, the extension of the theory to the case where many domain walls participate in the magnetization process is discussed