Daniel M. Meier

Conformational Behavior of Cinchonidine Revisited: A Combined Theoretical and Experimental Study

Conformational space of cinchonidine has been explored by means of ab initio potential and free energy surfaces, and the temperature-induced changes of conformational populations were studied by a combined NOESY-DFT analysis. The DFT-derived potential energy surface investigation identified four new conformers. Among them, Closed(7) is substantially relevant to fully understand the conformational behavior. The energy surfaces gave access to the favored transformation pathways at different temperatures (280-320 K). They also revealed the reasons for the negligible presence of energetically stable conformers and explained the experimentally observed temperature dependence of the populations.

Design and performance of a flow-through polarization-modulation infrared reflection-absorption spectroscopy cell for time-resolved simultaneous surface and liquid phase detection under concentration and temperature perturbations

Design and performance of a flow-through cell for polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) suitable for simultaneous monitoring of species on surface and in liquid phase on a molecular level at a high time resolution (ca. 1 s) are presented. In particular, the cell was designed to allow periodic concentration and temperature perturbations and thus excite physicochemical phenomena of interest occurring at solid-liquid interfaces. Utilizing the perturbations and spectral responses of both surface and liquid phase species, their dynamic behavior, kinetics, and correlations can be studied. The detection sensitivity is greatly enhanced by the data processing employed in modulation excitation spectroscopy (MES). The cell design is based on a theoretical model. The IR beam path through a multiple-phase system consisting of air, prism, and liquid as well as light reflection at the surface of a sample were considered in order to maximize the detected IR light intensity and absorption by surface molecules. Its high surface sensitivity was demonstrated by CO adsorption on a thin Pt film in a liquid phase. Combination of the PM-IRRAS with concentration MES led to a significant sensitivity enhancement for the detection of surface and liquid phase species. The temperature, tunable in a wide range from 263-343 K, could be controlled within an accuracy of 0.1 K and also modulated periodically in a completely reversible manner, thus allowing accurate temperature MES experiments. With these capabilities, dynamic physicochemical processes at solid-liquid interfaces can be sensitively investigated.

Polarization-modulation infrared reflection-absorption spectroscopy affording time-resolved simultaneous detection of surface and liquid phase species at catalytic solid–liquid interfaces

Polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) combined with concentration modulation allows simultaneous monitoring of dynamic evolutions of surface and liquid phase species during reactions at catalytic interfaces as demonstrated for the Pt-catalysed oxidation of CO by O2 in cyclohexane.

Detection and characterization of moving objects with aerial vehicles using inertial-optical flow

In this paper, we present a novel approach in combining visual and inertial measurements in non-static environments for first order characterization of the metric motion of non-static objects in the scene. Our approach leverages online estimated ego motion states and uses a novel inertial-optical flow (IOF) measurement analysis to identify moving objects and to characterize them in their angular and linear velocities. The novelty of our algorithm lies in the identification and segmentation of consistent optical flow outliers in the so-called kinematic space. These consistent outliers in combination with the IOF information for ego-motion estimation yield a first order estimation of the moving object in full 3D and in metric units. The approach is highly efficient as it only requires matched features in two consecutive images. We evaluate and demonstrate our algorithm in simulations and in real world tests.