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51.
Various adiabatic photochemical mechanisms are compared which lead to a product in the excited state and therefore often to strongly red-shifted fluorescence. The applicational aspects of this strong red shift are outlined with respect to scinitillators, solar collectors, and biological fluorescence probese. As an example, the unusual fluorecence properties of a pyrazalocoumarin derivative are described. 相似文献
52.
J. Kowalski F. Träger M. Vollmer G. zu Putlitz 《Zeitschrift für Physik A Hadrons and Nuclei》1985,320(2):353-354
A two laser excitation scheme has been applied to Ca atoms in an atomic beam. It permits to transfer narrow Doppler-free signals from a weak transition into a strong resonance line. This leads to a large increase of the signal-to-noise ratio and is of relevance for the application of the Ca intercombination transition as a possible new standard in the optical range. 相似文献
53.
W. Hoheisel U. Schulte M. Vollmer R. Weidenauer F. Träger 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1989,12(1-4):245-247
This paper reports the dissociation of supported metal clusters after illumination with low intensity visible laser light. The process is non-thermal and exhibits a resonant dependence on the laser frequency. This indicates that a surface plasmon excitation preceeds the dissociation. 相似文献
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Matthew V. Vollmer Dr. Jing Xie Ryan C. Cammarota Dr. Victor G. Young Jr. Dr. Eckhard Bill Prof. Laura Gagliardi Prof. Connie C. Lu 《Angewandte Chemie (International ed. in English)》2018,57(26):7815-7819
Formal nickelate(?I) complexes bearing Group 13 metalloligands (M=Al and Ga) were isolated. These 17 e? complexes were synthesized by one‐electron reduction of the corresponding Ni0→MIII precursors, and were investigated by single‐crystal X‐ray diffraction, EPR spectroscopy, and quantum chemical calculations. Collectively, the experimental and computational data support: 1) the strengthening of the Ni?M bond upon one‐electron reduction, and 2) the delocalization of the unpaired spin across the Ni and M atoms. An intriguing electronic configuration is revealed where three valence electrons occupy two σ‐type bonding interactions: Ni(3d )2→M and σ‐(Ni?M)1. The latter is an unusual Ni?M σ‐bonding molecular orbital that comprises primarily the Ni 4pz and M npz/ns atomic orbitals. 相似文献
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Development of an integrated microfluidic platform for dynamic oxygen sensing and delivery in a flowing medium 总被引:1,自引:0,他引:1
This paper describes a platform for real-time sensing of dissolved oxygen in a flowing microfluidic environment using an oxygen-sensitive luminescent dye (platinum octaethylporphyrin ketone) integrated into a micro-oxygenator device. Using a phase-based detection method, the luminescent decay lifetime of the dye was consistent with the linear Stern-Volmer relationship using both gaseous and aqueous samples. Maximum sensor resolution varied between 120-780 ppb across a range of dissolved oxygen (DO) concentrations ranging from 0-42.5 ppm. The sensor was subsequently used to determine the convective mass-transfer characteristics of a multi-layer polydimethylsiloxane (PDMS) microfluidic oxygenator. The membrane-based oxygenator showed excellent agreement with an analytical convection model, and the integrated oxygen sensor was accurate across a wide range of tested flow rates (0.05-5 mL min(-1)). The device is unique for its ease of fabrication and highly flexible configuration, as well as the novel incorporation of oxygen delivery and detection in a single micro-device. Potential applications include tissue engineering, cell culturing, and miniaturized bio-assays that require the delivery and/or detection of precise quantities of oxygen within a microfluidic construct. 相似文献
59.
Aluminium trichloride forms the adducts AlCl3 · NH2CH3, AlCl3 · 2NH2CH3, AlCl3 · 4NH2CH3; AlCl3 · NH3CH3Cl, AlCl3 · 2NH3CH3Cl. The interaction between AlCl3, PCl5 and NH3CH3Cl in the molar ratio 1:3:2 proceeds according to the reaction equation in “Inhaltsübersicht”. On applying other stoichiometric amounts, [Cl2(NHCH3)P? N(CH3)? AlCl3] · HCl and [Cl3P? N(CH3)? AlCl3] · HCl are obtained; the latter reacts as [Cl3P? NHCH3][AlCl4]. At the molar ratio AlCl3:PCl5:NH3CH3Cl = 1:2:4 a compound is formed being presumably the six-membered heterocycle formulated in “Inhaltsübersicht”. With [Cl3P?N? PCl3] and aluminium chloride [Cl3P?N? PCl3][AlCl4] is formed. 相似文献
60.
Fandiño AS Rais I Vollmer M Elgass H Schägger H Karas M 《Journal of mass spectrometry : JMS》2005,40(9):1223-1231
The application of two-dimensional electrophoresis for the identification of hydrophobic membrane proteins is principally hampered by precipitation of many of these proteins during first-dimension, isoelectric focusing. Therefore new strategies towards the identification and characterization of membrane proteins are being developed. In this work we present a direct and rapid approach from blue-native gels to mass spectrometry, which allows the analyses of complete complexes and prevents protein aggregation of hydrophobic regions during electrophoresis. We combine blue-native gel electrophoresis and liquid chromatography--nanospray-iontrap tandem mass spectrometry to analyze the composition of oxidative phosphorylation complexes I, III, IV and V from bovine-heart mitochondria as a model system containing a number of highly hydrophobic proteins. Bands from blue-native gels were subjected either to in-gel or to in-solution tryptic digestion. The obtained peptide mixtures were further analyzed by liquid chromatography--tandem mass spectrometry and the corresponding proteins were identified by database search. From a total of 86 proteins, 67 protein subunits could be identified including all highly hydrophobic components, except the ND4L and ND6 subunits of complex I. We demonstrate that liquid chromatography--tandem mass spectrometry combined to blue-native electrophoresis is a straightforward tool for proteomic analysis of multiprotein complexes, and especially for the identification of very hydrophobic membrane protein constituents that are not accessible by common isoelectric focusing/sodium dodecyl sulphate gel electrophoresis. 相似文献