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2. In surface reaction rate.limiting deposition, which occurred at chuck temperatures below 550~ a W-rich amorphous layer is formed at the interface with the Si substrate. Thi~ layer is nucleated by the surface reaction of WF~ with Si. Nonuniform, in.depth Si composition profiles become more uniform with increase of deposition temperature.3, The nucleated layers on Si by the surface reaction are amorphous with the Si composition, x, below 2.0. These results indicate that control of the surface reaction is needed to deposit films with a uniform composition profile.

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Constantly advancing computer simulations of biomolecules provide huge amounts of data that are difficult to interpret. In particular, obtaining insights into functional aspects of macromolecular dynamics, often related to cascades of transient events, calls for methodologies that depart from the well-grounded framework of equilibrium statistical physics. One of the approaches toward the analysis of complex temporal data which has found applications in the fields of neuroscience and econometrics is Granger causality analysis. It allows determining which components of multidimensional time series are most influential for the evolution of the entire system, thus providing insights into causal relations within the dynamic structure of interest. In this work, we apply Granger analysis to a long molecular dynamics trajectory depicting repetitive folding and unfolding of a mini β-hairpin protein, CLN025. We find objective, quantitative evidence indicating that rearrangements within the hairpin turn region are determinant for protein folding and unfolding. On the contrary, interactions between hairpin arms score low on the causality scale. Taken together, these findings clearly favor the concept of zipperlike folding, which is one of two postulated β-hairpin folding mechanisms. More importantly, the results demonstrate the possibility of a conclusive application of Granger causality analysis to a biomolecular system.