Effects of deposition dynamics on epitaxial growth

The dynamic effects, such as the steering and the screening effects during deposition, on an epitaxial growth (Cu/Cu(001)), is studied by kinetic Monte Carlo simulation that incorporates molecular dynamic simulation to rigorously take the interaction of the deposited atom with the substrate atoms into account. We find three characteristic features of the surface morphology developed by grazing angle deposition: (1) enhanced surface roughness, (2) asymmetric mound, and (3) asymmetric slopes of mound sides. Regarding their dependence on both deposition angle and substrate temperature, a reasonable agreement of the simulated results with the previous experimental ones is found. The characteristic growth features by grazing angle deposition are mainly caused by the inhomogeneous deposition flux due to the steering and screening effects, where the steering effects play the major role rather than the screening effects. Newly observed in the present simulation is that the side of mound in each direction is composed of various facets instead of all being in one selected mound angle even if the slope selection is attained, and that the slope selection does not necessarily mean the facet selection.Comment: 9 pages, 10 figure

A Hedged Monte Carlo Approach to Real Option Pricing

In this work we are concerned with valuing optionalities associated to invest or to delay investment in a project when the available information provided to the manager comes from simulated data of cash flows under historical (or subjective) measure in a possibly incomplete market. Our approach is suitable also to incorporating subjective views from management or market experts and to stochastic investment costs. It is based on the Hedged Monte Carlo strategy proposed by Potters et al (2001) where options are priced simultaneously with the determination of the corresponding hedging. The approach is particularly well-suited to the evaluation of commodity related projects whereby the availability of pricing formulae is very rare, the scenario simulations are usually available only in the historical measure, and the cash flows can be highly nonlinear functions of the prices.Comment: 25 pages, 14 figure

Remote heart rate monitoring - Assessment of the Facereader rPPg by Noldus

Remote photoplethysmography (rPPG) allows contactless monitoring of human cardiac activity through a video camera. In this study, we assessed the accuracy and precision for heart rate measurements of the only consumer product available on the market, namely the Facereader™ rPPG by Noldus, with respect to a gold standard electrocardiograph. Twenty-four healthy participants were asked to sit in front of a computer screen and alternate two periods of rest with two stress tests (i.e. Go/No-Go task), while their heart rate was simultaneously acquired for 20 minutes using the ECG criterion measure and the Facereader™ rPPG. Results show that the Facereader™ rPPG tends to overestimate lower heart rates and underestimate higher heart rates compared to the ECG. The Facereader™ rPPG revealed a mean bias of 9.8 bpm, the 95% limits of agreement (LoA) ranged from almost -30 up to +50 bpm. These results suggest that whilst the rPPG Facereader™ technology has potential for contactless heart rate monitoring, its predictions are inaccurate for higher heart rates, with unacceptable precision across the entire range, rendering its estimates unreliable for monitoring individuals

Surface chemistry of water atomised aluminium alloy powders

This paper focuses on the characterisation of chemical composition and morphology of the surface oxide film in water atomised (WA) aluminium powders as a function of technological regimes (atomisation temperature and water pressure) by AES. The surface film mainly consists of aluminium oxides. However, magnesium is enriched and oxidised on the powder surface. Powders atomised at a higher water pressure are usually less oxidised than those atomised at a lower pressure. The surface of powders is covered by surface oxides of non-uniform thickness. Rather high oxide islands cover 30-70% of the surface. The rest is covered with a thin oxide film of three to maximal eight monolayers

Reactive Electrophilic OI Species Evidenced in High Performance Iridium Oxohydroxide Water Oxidation Electrocatalysts

Although quasi-amorphous Ir-oxohydroxides have repeatedly been identified as superior oxygen evolution reaction (OER) electrocatalysts, an exact description of the performancerelevant species has so far remained a challenge. In this context, we report on the characterization of hydrothermally prepared Ir^III/IV-oxohydroxides exhibiting exceptional OER-performance. It was found that holes in the O2p states of Ir^III/IV-oxohydroxides result in reactive O^I--species identified by characteristic NEXAFS-features. A prototypical titration reaction based on CO as a probe molecule shows that these O^I--species are highly susceptible to nucleophilic attack at room temperature. Similarly to pre-activated oxygen involved in the biological OER in Photosystem II, the electrophilic O^I--species evidenced in Ir^III/IV-oxohydroxides are suggested to be precursors to species involved in the O-O bond formation during electrocatalytic OER. CO-titration also highlights a link between OER-performance and the surface/sub-surface mobility of O^I--species. The superior electrocatalytic properties of Ir^III/IV-oxohydroxides are thus explained by their ability to accommodate pre-activated electrophilic O^I--species able to migrate within the lattice

An Unusal Case of Facile Non‐Degenerate P-C Bond Making and Breaking

Oxidation of Li/X phosphinidenoid complex 2, obtained via selective deprotonation from the P‐H precursor 1, with [Ph3C]BF4 led to the formation of two P‐F substituted diorganophosphane complexes 6,7; the latter tautomer 7 formed via H‐shift from 6. In contrast, oxidation of 2 with [(p‐Tol)3C]BF4 led to three major and one minor intermediates at low temperature, which we tentatively assign to two pairs of P‐C atropisomers 10a,a′ and 10c,c′ and which differ by the relative orientations of their CH(SiMe3)2 and W(CO)5 groups. Conversion of all isomers led finally to complex 11 having a ligand with a long P-C bond to the central trityl* carbon atom, firmly established by single‐crystal X‐ray analysis. DFT calculations at the B3LYP/def2‐TZVPP//BP86/def2‐TZVP level of theory on real molecular entities revealed the structures of the in situ formed combined singlet diradicals (4+5 and 5+9) and the nature of intermediates on the way to the final product, complex 11. Remarkable is that all isomers of 11 possess relative energies in the narrow energy regime of about 20 kcal mol−1. A preliminary study revealed that complex 11 undergoes selective P-C bond cleavage at 75 °C in toluene solution