A structurally guided method for the decomposition of expression in music performance

A method for separating, profiling, and quantifying the contributions of different structural components to expressive musical performance is described. The method is demonstrated through its application to a set of expert piano performances of a short piece from the classical period. The results show that the output of the method aids in the understanding of how the different structural components in a piece of music combine in the generation of an expressive performance. A second demonstration applies the method to performances at different tempi to illustrate its effectiveness in pinpointing the structural features responsible for small but statistically significant differences between performances. The method is compared with other approaches to the analysis and modeling of musical performance, and a number of potential applications are identified.     

Cassie-Baxter to Wenzel state wetting transition: Scaling of the front velocity

We experimentally study the dynamics of water in the Cassie-Baxter state to Wenzel state transition on surfaces decorated with assemblies of micrometer-size square pillars arranged on a square lattice. The transition on the micro-patterned superhydrophobic polymer surfaces is followed with a high-speed camera. Detailed analysis of the movement of the liquid during this transition reveals the wetting front velocity dependence on the geometry and material properties. We show that a decrease in gap size as well as an increase in pillar height and intrinsic material hydrophobicity result in a lower front velocity. Scaling arguments based on balancing surface forces and viscous dissipation allow us to derive a relation with which we can rescale all experimentally measured front velocities, obtained for various pattern geometries and materials, on one single curve.     

The unexpected,thermally induced,cyclization of 1,16-dimethylhexahelicenes into 5h-benzo[c,d]pyrene-5-spiro-1'-indane derivatives

Heating of concentrated solutions of 1,3,14,16-tetramethylhexahelicene (1) at temperatures between 180 and 300° results in the formation of two spiro compounds (3 and 4) containing a benzopyrene and an indane unit. Dilute solutions only racemize. A similar behaviour is observed with 1,16-dimethylhexahelicene (2) but not with the 1,3- and 1,14-dimethyl derivatives. Presumably the carbon skeleton of the pyrene moiety arises via a sigmatropic H-shift from C₁-CH₃ to C₁₉, followed by an electrocyclic reaction. Suggestions are given for the mechanism of the subsequent rearrangements which lead to 3 and 4.     

Conformational studies on helicenes—IX1: A hexahelicene containing an aromatic,carbocyclic, five-membered ring

The reaction of phenathro[3,4-c]fluorene (1) with lithium in tetrahydrofuran (THF) or hexamethylphosphoric triamide (HMPT) leads to the fully aromatic phenanthro[3,4-c]fluorenyl anion (2). The influence of the ring current of the five-membered ring and the negative charge on the proton chemical shifts has been analyzed. The low-field position of the A-portion (H(16)) is ascribed to the nearby position of the Li-cation. Even in HMPT the Li^?+2^? salt appears to be present as a contact ion pair.     

Die oxidative Kopplung von 2,6-Xylenol mit polymeren Komplexen von Cu. 2. Mitt. Physikochemische Untersuchung an den Cu(II)-Komplexen mit partiell dimethylaminomethyliertem Polystyrol

Ohne Zusammenfassung     

Spontaneous breakdown of superhydrophobicity

In some cases water droplets can completely wet microstructured superhydrophobic surfaces. The dynamics of this rapid process is analyzed by ultrahigh-speed imaging. Depending on the scales of the microstructure, the wetting fronts propagate smoothly and circularly or-more interestingly-in a stepwise manner, leading to a growing square-shaped wetted area: entering a new row perpendicular to the direction of front propagation takes milliseconds, whereas once this has happened, the row itself fills in microseconds ("zipping"). Numerical simulations confirm this view and are in quantitative agreement with the experiments.     

The discretized flow on domains of attraction: a structural stability result

It is well known that, for stepsize sufficiently small, compactattractors of ordinary differential equations persist underdiscretization. The present paper describes the structure ofthe discrete-time dynamical system obtained via discretizationon A(M_h)\M_h where M_h is the approximate attractor and A(M_h)is its domain of attraction. The existence of a smooth embeddinginto a continuous-time parallelizable flow is proved. The constructioncan be used to define sections for discretizations and can beinterpreted as a justification of the method of modified equations.     

Photophysics of intramolecular electron donor—acceptor systems; N-carbazolyl(CH2)ntetrachlorophthalimide

In systems N-carbazolyl—(CH₂)_n—tetrachlorophthalimide (n = 2, 3, 4, 7) virtually complete quenching of the carbazole fluorescence via an intramolecular electron-transfer mechanism occurs, with concomitant formation of an emissive polar excited state. The rate of formation of this polar excited state is found to exceed considerably those reported for formation of intramolecular exciplex states in other non-conjugated bichromophoric systems with a less pronounced electron donor—acceptor character.     

Superstability of surface nanobubbles

Shock wave induced cavitation experiments and atomic force microscopy measurements of flat polyamide and hydrophobized silicon surfaces immersed in water are performed. It is shown that surface nanobubbles, present on these surfaces, do not act as nucleation sites for cavitation bubbles, in contrast to the expectation. This implies that surface nanobubbles are not just stable under ambient conditions but also under enormous reduction of the liquid pressure down to -6 MPa. We denote this feature as superstability.     

The thermal racemization of methyl-substituted hexahelicenes

Rates of racemization of several Me-substituted hexahelicenes have been measured. It appeared that Me groups at the positions 3, 4, 13 and 14 have no influence; at the positions 2 and 15 the effect is small; Me-substitution at C(1) and C(16) leads, however, to a large increase of the free energy of activation. From an analysis of the data the suggestion is made that the conformation of highest energy during racemisation of 1-methyl- and 1,16-dimethylhexahelicene (and possibly also of hepta and octahelicene) is that with the terminal rings in orthogonal position.