Existenzbeweis für cnoidal waves unter berücksichtigung der oberflächenspannung

Ohne ZusammenfassungHerrn Prof. Herbert Beckert zum 50. Geburtstag Vorgelegt von J. Serrin     

A random synthetic jet array driven turbulence tank

We measure the flow above an array of randomly driven, upward-facing synthetic jets used to generate turbulence beneath a free surface. Compared to grid stirred tanks (GSTs), this system offers smaller mean flows at equivalent turbulent Reynolds numbers with fewer moving parts.

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All Eyes on Visible-Light Peroxyoxalate Chemiluminescence Read-Out Systems

Chemiluminescence (CL) reactions have been widely employed and explored over the past 50 years because they offer unique light emission upon a defined chemical stimulus. In this Minireview, we focus on peroxyoxalate (PO) compounds because they feature very high quantum yields tuneable over the entire visible spectrum, allowing for visible-light detection by the naked eye without the necessity for expensive analytical instruments. Although analytical methods have been extensively described, PO-CL read-out is a strongly emerging field with ample industrial potential. The state-of-the-art PO-CL detection read-out systems for various key analytes is here explored. In particular, structural requirements, recent developments of PO-CL read-out probes and current limitations of selected examples are detailed. Furthermore, innovative approaches and synthetic routes to push the boundaries of PO-CL reactions into biological systems are highlighted. Underpinned by recent contributions, we share perspectives on embedding PO-CL molecules into polymeric materials, which they consider the next step in designing high performance solid-phase read-out systems.     

The U$mathcal {U}$-Lagrangian,Fast Track,and Partial Smoothness of a Prox-regular Function

Set-Valued and Variational Analysis - When restricted to a subspace, a nonsmooth function can be differentiable. It is known that for a nonsmooth convex function and a point, the Euclidean space...     

Boron chelates and boron-metal chelates. XI. Constitution of Diphenylboron Chelates from Salicylaldehyde and amino compounds with functional groups

The chelates 1 — 5 were synthesized from salicylaldehyde, an amine component, and diphenylboric anhydride. Their elementary analytic and spectroscopic investigation showed that diphenylboron chelates were formed and not monophenylboron chelates (BC₆H₅ group belongs to two chelate rings). The ¹H-NMR spectroscopic investigation of the thermal decomposition products of 3 shows that, in addition to the release of the ethanol bonded by intermolecular hydrogen bridges, benzene is eliminated while the monophenylboron chelate is formed. By means of UV, IR, and NMR data (¹H, ¹³C and ¹¹B) it has been proved that 1 — 3 and 5 show ring closures in the “salicylaldehyde” part of the azomethine chelating agent.     

Protoberberines from Reissert-Compounds. Part IX [1]. An Alternative Approach to Dibenzoquinolizine- and Isoquinonaphthyridin-13a-carboxylic Acids, a Novel Synthesis of Alangimarine

3,4-Dihydroisoquinoline-Reissert-compounds were alkylated to 1-benzyl- and 1-picolyl-derivatives, which in turn could selectively be hydrolized yielding various carboxylic acids, among others certain amino acids related to 3,4-deoxynorlaudanosoline carboxylic acid (DNLCA). These on treating with ethanolic KOH underwent cyclization to dibenzoquinolizine- and isoquinonaphthyridine-13a-carboxylic acids. Alternatively this cyclization also could be achieved by a more convenient one-pot procedure starting from the same dihydro-Reissert-compounds. Thermal decarboxylation afforded among others the alangia alkaloids alangimarine and dihydroalangimarine.     

Stable rank and real rank for some classes of group -algebras

We investigate the real and stable rank of the -algebras of locally compact groups with relatively compact conjugacy classes or finite-dimensional irreducible representations. Estimates and formulae are given in terms of the group-theoretic rank.

     

Surface chemistry of ultrathin films of histidine on gold as probed by high-resolution synchrotron photoemission

Procedures for the vacuum deposition of thin histidine films on polycrystalline Au(111) and their characterization with high-resolution synchrotron-radiation-based photoelectron spectroscopy are reported. The chemical form of histidine (anionic vs zwitterionic) and the nature of its interactions with the substrate (strong ionic-covalent vs weak van der Waals bonding) in mono- and multilayer films are analyzed. It is shown that water adsorption on a pre-prepared histidine film at 100 K results in protonation of histidine molecules and partial formation of hydroxyl anions. These chemical effects are carefully differentiated from spectral changes associated with radiation damage of the histidine films.     

The structure of 4-methylphenol and its water cluster revealed by rotationally resolved UV spectroscopy using a genetic algorithm approach

The structure of 4-methylphenol (p-cresol) and its binary water cluster have been elucidated by rotationally resolved laser-induced fluorescence spectroscopy. The electronic origins of the monomer and the cluster are split into four sub-bands by the internal rotation of the methyl group and of the hydroxy group in case of the monomer, and the water moiety in case of the cluster. From the rotational constants of the monomer the structure in the S1 state could be determined to be distorted quinoidally. The structure of the p-cresol-water cluster is determined to be trans linear, with a O-O hydrogen bond length of 290 pm in the electronic ground state and of 285 pm in the electronically excited state. The S1-state lifetime of p-cresol, p-cresol-d1, and the binary water cluster have been determined to be 1.6, 9.7, and 3.8 ns, respectively.