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We introduce a notion of quantum mechanical resonance that does not rely on analytic continuation of resolvent or scattering matrix and relate it to slow temporal decay of certain distinguished resonant states. We proceed to prove existence of resonances for the generalized many body Schrόdinger operator for a rather large class of potentials containing Coulomb and Yukawa, but also nonsymmetric and nonanalytic potentials with Coulomblike singularities at the origin and certain differentiability and decay properties.

It is shown for a series of tyrosine-derivatives and tyrosine-containing peptides that the amide group in combination with electron-withdrawing substituents quenches the fluorescence of the phenol moiety. The ammonium group has the strongest electron-withdrawing effect and thus the largest influence on the quenching rate. The peptide group itself does not quench the fluorescence. In a series of peptides with an increasing number of alanines the decreasing quenching efficiency of the peptide group due to the greater distance of the ammonium group is demonstrated. In tyrosine-containing di- and tripeptides a linear correlation between the 13C-NMR chemical shift delta of the C alpha atom of various aliphatic amino acids and the fluorescence-quenching constant confirms the hypothesis that electron-withdrawing and -donating groups are modulating the fluorescence-quenching efficiency of the peptide group. In small peptides the fluorescence lifetime of tyrosine is characteristic for the neighboring amino acids. Using model substances the redox properties of a peptide group and the phenol ring were studied electrochemically. The highest occupied molecular orbital of the tyrosine (1.4 V vs saturated calomel electrode [SCE]) and the lowest unoccupied molecular orbital of the peptide group (-3.12 V vs SCE) have appropriate energies for a photoinduced electron transfer reaction. For solute-quenching experiments quencher molecules can be systematically selected.

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Two-dimensional (2D) temperature measurements in engines are required for the detailed understanding of the combustion process. Because of the unsteady and turbulent nature of engine combustion, these measurements must be performed on a single-shot basis to obtain cycle-resolved results. Details of the flame front structure are also important to know for the numerical modeling of internal combustion processes. Simultaneous measurements of temperature and hydroxyl radical distributions provide such data sets. The combustion of methane in a fully transparent square piston engine was studied with a combination of 2D laser-induced fluorescence of hydroxyl radicals and 2D Rayleigh scattering. A tunable KrF excimer laser at 248 nm was used for the measurements. The wavelength of the laser was tuned to excite the P2(8) transition in the OH (3,0) band of the AX system. Spectral filtering of the resulting fluorescence to detect solely the fluorescence from the (3,2) band significantly reduces the effect of collisional quenching imposed to the fluorescence of the predissociating v' = 3 level by vibrational energy transfer (VET) to lower vibrational levels. Using a second camera, which only records the Rayleigh signals after appropriate filtering, allows the simultaneous measurement of temperature fields with a single laser. The analysis of corresponding OH and temperature images allowed the decision that the combustion conditions are in a regime where the flamelet approach for modeling is appropriate. Good agreement with model predictions has been achieved for the peak temperatures.

The high spectral brightness of tunable high power excimer lasers allows the two‐ and three‐dimensional application of techniques like laser‐induced fluorescence (LIF), Mie and Rayleigh scattering for industrial applications. The construction of these lasers allows easy transportation and installation to perform measurements at combustion facilities which can not be moved. In combination with suitable filters and gated image‐intensified CCD cameras techniques are now available to measure multi‐dimensional distributions of temperatures and concentrations. Simultaneous measurements of temperature fields and hydroxyl radical distributions were performed to study the influence of turbulence on large premixed natural gas flames. A combination of temperature and nitric oxide concentration measurements yielded information about the correlations between NO formation and burner design in domestic gas burners. LIF and Mie scattering of fuel and hydroxyl radicals were used for measurements in IC engine simulators, Otto and Diesel engines.

A new filler material is presented and tested to produce light-weight aluminium alloy composites: the pore space between nano-structured silica-aerogel granulates is infiltrated with Al-alloy melts. Since these filler materials have vanishing density (100 kg m −3 ), they need not to be removed from the final cast product. Their shape, size and volume fraction determine the materials' properties. Different methods were used to prepare metal-aerogel syntactic foam composites: centrifugal casting, squeeze and suction casting. The last method gave the best results, using an Al-11Si melt. We produced circular and rectangular bars up to 500-mm length. The composite material has a density of around 900 kg m −3 , a yield stress of 8 MPa and absorbs 8 kJ kg −1 mechanical energy.