TY - THES A1 - Vergin, Annika T1 - Charakterisierung von Metallosupramolekularen Polyelektrolyten mittels analytischer Ultrazentrifugation Y1 - 2008 CY - Potsdam ER - TY - BOOK A1 - Koetz, Joachim A1 - Kosmella, Sabine T1 - Polyelectrolytes and nanoparticles T3 - Springer laboratory manuals in polymer science Y1 - 2007 SN - 3-540-46381-X PB - Springer-Verlag CY - Heidelberg ER - TY - JOUR A1 - Koetz, Joachim A1 - Andres, S. A1 - Kosmella, Sabine A1 - Tiersch, Brigitte T1 - BaSO4 nanorods produced in polymer-modified bicontinuous microemulsions N2 - The influence of the water soluble polymer poly(ethylene glycol) (PEG) on structure formation in the quasiternary system sodium dodecylsulfate (SDS)/pentanol-xylene/water was checked by means of conductometry, rheology, and micro differential calorimetry. The polymer induces the formation of an isotropic phase channel between the o/w and w/o microemulsion. The transition from the normal as well as from the inverse micellar to the bicontinuous phase range can be detected by conductometry, rheology as well as micro-DSC. As a result of polymer-surfactant interactions, the spontaneous curvature of the surfactant film is changed and a sponge phase is formed. The bicontinuous phase is characterized by a moderate shear viscosity, a Newtonian flow behaviour, and the disappearence of interphasal water in the heating curve of the micro-DSC. When the polymer-modified bicontinuous phase is used as a template phase for the nanoparticle formation, spherical BaSO4 nanoparticles were formed. During the following solvent evaporation process the primarily formed spherical nanoparticles aggregate to nanorods and triangular structures due to the non-restriction of the bicontinuous template phase in longitudinal direction Y1 - 2006 UR - http://www.ingentaconnect.com/content/vsp/ci U6 - https://doi.org/10.1163/156855406777408629 SN - 0927-6440 ER - TY - JOUR A1 - Engelhard, Sonja A1 - Kumke, Michael Uwe A1 - Löhmannsröben, Hans-Gerd T1 - Examples of the application of optical process and quality sensing (OPQS) to beer brewing and polyurethane foaming processes N2 - Optical methods play an important role in process analytical technologies (PAT). Four examples of optical process and quality sensing (OPQS) are presented, which are based on three important experimental techniques: near- infrared absorption, luminescence quenching, and a novel method, photon density wave (PDW) spectroscopy. These are used to evaluate four process and quality parameters related to beer brewing and polyurethane (PU) foaming processes: the ethanol content and the oxygen (O-2) content in beer, the biomass in a bioreactor, and the cellular structures of PU foam produced in a pilot production plant Y1 - 2006 UR - http://www.springerlink.com/content/100417 U6 - https://doi.org/10.1007/s00216-005-3364-4 SN - 1618-2642 ER - TY - JOUR A1 - Kamm, Birgit A1 - Kamm, Michael A1 - Schmidt, Matthias A1 - Starke, Ines A1 - Kleinpeter, Erich T1 - Chemical and biochemical generation of carbohydrates from lignocellulose-feedstock (Lupinus nootkatensis) : quantification of glucose N2 - Different chemical and enzymatic methods were applied for the hydrolysis of main stems from Lupinus nootkatensis (harvest November 2002). The whole process (all steps) is based on the lignocellulose-feedstock biorefinery regime. The acid hydrolysis of L. was performed with concentrated hydrochloric acid; advantages in this process are exothermic hydrolysis and the possibility of acid recovery. Enzymatic hydrolysis achieved high yields of fermentable carbohydrates (regarding to input cellulose) with high selectivity. However, this way requires the generation of cellulose from L. by chemical pulping. Monosaccharide derivatives thus obtained were identified by their GC retention times and the corresponding MS fragmentation. Hexamethyldisilazane was used as derivatization reagent to prepare the trimethylsilyl derivatives of the carbohydrates and of the degradations products of cellulose from the different fractions. The glucose content was quantified by GC peak integration with respect to an internal standard. Y1 - 2006 UR - http://www.sciencedirect.com/science/journal/00456535 U6 - https://doi.org/10.1016/j.chemosphere.2005.03.073 SN - 0045-6535 ER - TY - JOUR A1 - Kumke, Michael Uwe A1 - Eidner, Sascha A1 - Krüger, Tobias T1 - Fluorescence quenching and luminescence sensitization in complexes of Tb3+ and Eu3+ with humic substances N2 - Intrinsic fluorescence quenching of humic substances (HS) and the sensitization of Ln(3+) luminescence (Ln3+ Tb3+, Eu3+) in HS complexes were investigated. Both measurements yielded complementary information on the complexation of metals by HS. Large differences between fulvic acids(FA)and humic acids (HA) were found. From time-resolved luminescence measurements it is concluded that a combination of energy transfer and energy back transfer between HS and Ln(3+) is responsible for the observed luminescence decay characteristics. In the case of Eu3+, an additional participation of charge-transfer states is suggested. A new concept for the evaluation of the sensitized luminescence decays of Ln(3+) was adapted Y1 - 2005 ER - TY - JOUR A1 - Apitz, Sabine E. A1 - Bell, Elanor M. A1 - Damgaard, Lars A1 - Gilbert, Franck A1 - Glud, R A1 - Hall, P. O. J. A1 - Kershaw, P. J. A1 - Nickel, L A1 - Parker, R A1 - Rabouille, Christophe A1 - Shimmield, Grahamm A1 - Solan, Martin A1 - Soltwedel, Thomas A1 - Spagnoli, Federico A1 - Witte, Ursula T1 - Coastal Ocean Benthic Observatories (COBO) : integrated tools for the in situ observation and study of benthic ecosystem biogeochemical processes Y1 - 2005 ER - TY - JOUR A1 - Strehmel, Veronika A1 - Sarker, A. M. A1 - Lahti, P. M. A1 - Karasz, F. E. A1 - Heydenreich, Matthias A1 - Wetzel, Hendrik A1 - Haebel, Sophie A1 - Strehmel, Bernd T1 - One- and two-photon photochemistry and photophysics of poly(arylenevinylene)s containing a biphenyl moiety N2 - Photochemical and photophysical properties were investigated for poly(arylenevinylene)s containing a flexible biphenyl "hinge" unit by applying one-photon (OP) and two-photon (TP) excitation to explore excited-state properties. The poly(arylenevinylene)s were poly[(2,5-dihexyloxy-p-phenylenevinylene)-alt-(4,4'-dihexyloxy-3,3'-biph enylenevinylene)] (1), poly[(2,5-dihexyloxy-p-phenylenevinylene)-alt-(2,2'-dihexyloxy-3,3'-biph enylenevinylene)] (2), and poly[(2,5-dihexyloxy-p-phenylenevinylene)-alt-(2,2'-biphenylene-vinylene )] (3). Effective emission quantum yields and related photonic properties were evaluated on a realistic per-chromophore basis using effective conjugation lengths based on the Strickler-Berg relationship. intramolecular photocyclization was deduced to occur in the one case where the biphenyl molecular connectivity permitted the reaction, based on matrix- assisted loser desorption/ionization time-of-flight (MALDI-TOF), heteronuclear multiple-quantum coherence (HMQC)-NMR, and gel-permeation chromatography (GPC) results. The various photoprocesses could be induced by either OP or TP excitation, though the first excited singlet state is the photoactive state. The higher excitation energy 1 of the TP excited state favors indirect population of the S, state by electronic coupling between the TP and OP excited states [lambda(max)(TPE) (nm): 726; delta (GM)([9]): 1 = 229, 2 = 215, 3 = 109). Photochemical processes occurring from the lowest OP excited state (S-1) could therefore also be indirectly induced by TP excitation Y1 - 2005 SN - 1439-4235 ER - TY - JOUR A1 - Ritschel, Thomas A1 - Kuntz, Philip J. A1 - Zulicke, Lutz T1 - Structure and dynamics of cationic van-der-Waals clusters : I. Binding and structure of protonated argon clusters N2 - The geometric structure and bonding properties of medium-sized ArnH+ clusters (n = 2-35), in which a proton is wrapped up in a number of Ar atoms, are investigated by applying a diatomics-in-molecules (DIM) model with ab-initio input data generated by means of multi-reference configuration-interaction (MRCI) computations. For the smaller complexes, n = 2-7, cross-checking calculations employing the coupled-cluster approach (CCSD) with the same one-electron atomic basis set as for the input data calculations (aug-cc-pVTZ from Dunning), show good agreement thus justifying the extension of the DIM study to larger n. Local minima of the multi-dimensional potential-energy surfaces (PES) are determined by combining a Monte-Carlo sampling followed, for each generated point, by a steepest-descent optimization procedure. For the electronic ground state of the ArnH+ clusters, the global minimum (corresponding to the most stable structure of the cluster) as well as secondary minima are found and analyzed. The structural and energetic data obtained reveal the building-up regularities for the most stable structures and make it possible to formulate a simple increment scheme. The low-lying excited states are also calculated by the DIM approach; they all turn out to be globally repulsive Y1 - 2005 ER - TY - JOUR A1 - Löhmannsröben, Hans-Gerd T1 - Laser-induced fluorescence (LIF) spectroscopy and laser-based ion mobility (IM) spectrometry for in-situ analysis of contaminated soils Y1 - 2005 ER -