A novel monochromator for experiments with ultrashort X‐ray pulses

Aiming at advancing storage‐ring‐based ultrafast X‐ray science, over the past few years many upgrades have been undertaken to continue improving beamline performance and photon flux at the Femtoslicing facility at BESSY II. In this article the particular design upgrade of one of the key optical components, the zone‐plate monochromator (ZPM) beamline, is reported. The beamline is devoted to optical pump/soft X‐ray probe applications with 100 fs (FWHM) X‐ray pulses in the soft X‐ray range at variable polarization. A novel approach consisting of an array of nine off‐axis reflection zone plates is used for a gapless coverage of the spectral range between 410 and 1333 eV at a designed resolution of E/ΔE = 500 and a pulse elongation of only 30 fs. With the upgrade of the ZPM the following was achieved: a smaller focus, an improved spectral resolution and bandwidth as well as excellent long‐term stability. The beamline will enable a new class of ultrafast applications with variable optical excitation wavelength and variable polarization.     

Bromination of 2,1,3-benzothiadiazoles

The bromination of 2,1,3-benzothiadiazoles in 47% hydrobromic acid at elevated temperature has led to a general preparative method for the synthesis in high yield of otherwise difficulty accessible brominated 2,1,3-benzothiadiazoles. The typical addition reaction is apparently eliminated under these reaction conditions and substitution takes place exclusively. Bromination of 2,1,3-benzothiadiazole occurs successively at positions 4 and 7. 4-Substituted 2,1,3-benzothia-diazoles are selectively brominated at position 7. 5-Bromo- and 5-methyl-2,1,3-benzothiadiazole are brominated consecutively at positions 4 and 7.     

Amperometric sensor for ethanol based on one-step electropolymerization of thionine-carbon nanofiber nanocomposite containing alcohol oxidase

Thionine had strong interaction with carbon nanofiber (CNF) and was used in the non-covalent functionalization of carbon nanofiber for the preparation of stable thionine-CNF nanocomposite with good dispersion. With a simple one-step electrochemical polymerization of thionine-CNF nanocomposite and alcohol oxidase (AOD), a stable poly(thionine)-CNF/AOD biocomposite film was formed on electrode surface. Based on the excellent catalytic activity of the biocomposite film toward reduction of dissolved oxygen, a sensitive ethanol biosensor was proposed. The ethanol biosensor could monitor ethanol ranging from 2.0 to 252 μM with a detection limit of 1.7 μM. It displayed a rapid response, an expanded linear response range as well as excellent reproducibility and stability. The combination of catalytic activity of CNF and the promising feature of the biocomposite with one-step non-manual technique favored the sensitive determination of ethanol with improved analytical capabilities.     

Über die Kristallisation von Jod und Jodiden in Gelen

Zusammenfassung Aus einer Reihe von Untersuchungen über Bildung, Niederschlagung, scheinbaren Bewegung und Austausch von kristallinem Jod und unl?slichen kristallinen Jodiden in verschiedenen Gelen und anderen Mitteln wurde gefolgert, da? die Prozesse der Niederschlagung des Reaktionsproduktes und der Diffusion dieses Produktes nicht voneinander getrennt werden k?nnen. Es wurde darauf hingewiesen, da? die offensichtliche Wanderung von kristallinem Jod und unl?slichen kristallinen Jodiden in Gelstrukturen sich als eine Folge der Wiederaufl?sung in einem Teil der Kristallmasse und der Wiederablagerung an einem andern Teile zu ergeben scheint. Untersuchungen über den Austausch von kristallinem Jod durch unl?sliche Jodide und umgekehrt haben gezeigt, da? unter gewissen passenden Diffusionsbedingungen, wie z. B. im Kiesels?uregel, sich pseudomorphe Kristalle bilden k?nnen. Pseudomorphe Kristalle wurden in kapillaren R?umen zwischen Glasplatten nicht erhalten, obzwar sich eine ausgesprochene Neigung hierzu zeigte. Material wurde dargelegt, um zu zeigen, da? sich verschiedene Arten von Jodablagerungen als eine Folge der Wirkung des Mittels ergeben k?nnen. Diese Ablagerungen k?nnen sich von kolloiden bis zu makroskopischen Dimensionen und von sehr verzerrten bis zu fast vollkommenen kristallinen Formen erstrecken. Unter gewissen Bedingungen scheinen sich Somatoide zu bilden. Umgebungen, in denen diese Reaktionen ausgeführt wurden, waren a) verschiedene Gele, b) Schichten zwischen Glasplatten, c) Poren absorbierenden Papiers und d) Membranoberfl?chen.     

Air Supply Mode Effects on Ozone Production of Surface Dielectric Barrier Discharge in a Cylindrical Configuration

Plasma Chemistry and Plasma Processing - We investigated the air supply mode effects on ozone production of the surface dielectric barrier discharge in the cylindrical configuration. The air into...     

Rook Poset Equivalence of Ferrers Boards

A natural construction due to K. Ding yields Schubert varieties from Ferrers boards. The poset structure of the Schubert cells in these varieties is equal to the poset of maximal rook placements on the Ferrers board under the Bruhat order. We determine when two Ferrers boards have isomorphic rook posets. Equivalently, we give an exact categorization of when two Ding Schubert varieties have identical Schubert cell structures. This also produces a complete classification of isomorphism types of lower intervals of 312-avoiding permutations in the Bruhat order.     

A new dendrimer scaffold for preparing dimers or tetramers of biologically active molecules

Synthesis of a new scaffold derived from iminodipropionic acid for the preparation of peptide dimers and tetramers is described.     

A Fair Allocation of County Cricket Opponents

Each team in the English County Cricket Championship plays against some other teams twice a year, and others only once. This paper describes a case study whose aim was to overcome this inherent unfairness by producing a four-year schedule of opponents which was as fair as possible, and could be easily seen to be fair, while still allowing for traditional rivalries. The schedule also needed to be satisfactory in regard to several other constraints and objectives. Various simple heuristics were used; these are described in some detail. Of particular interest is the effectiveness of a ‘local non-worsening’ approach when the objective is to find any feasible solution. This is equivalent to simulated annealing at a constant temperature of absolute zero.     

The minimal free resolution of a Borel ideal

We consider the Eliahou–Kervaire minimal free resolution of a 0-Borel ideal and its applications.