100 Jahre Einkristallzucht aus der Schmelze

Cars, television, mobile phones, digital cameras, cash machines: Daily life is strongly affected by microchips produced from high purity silicon single crystals via thin wafers. Most of these single crystals are prepared by a process invented by the German‐Polish scientist Jan Czochralski in 1916 in the “Kabelwerk Oberspree (KWO)” of the “Allgemeine Elektricitätsgesellschaft (AEG)” in Berlin‐Oberschöneweide. Czochralski discovered the famous method to pull single crystals by accident: Deep in thought, he dipped his pen not into an ink pot but into a crucible with liquid tin, both standing next to one another on his desk. Quickly he pulled his pen out and observed a thin thread of tin emerging from the tip. After etching, the thread was identified as a single crystal of tin. This observation is probably one of the most important technical inventions of the first half of the 20^th century. In 1917, he left the AEG in Berlin and worked in the metal research laboratory, later belonging to the “Metallgesellschaft”, in Frankfurt/Main. Until today, wafers of high‐purity silicon are prepared by the Czochralski method. Silicon wafers with 200 mm diameter were produced in 1990, 300 mm wafers in 2001. The production of wafers with 450 mm diameter was expected for 2016. Siltronic produced in 2009 the first dislocation‐free silicon single crystal with 450 mm diameter, and other companies followed. However, until now, the 450 mm technology is not standard. This is due to a combination of very high investment costs needed to establish the 450 mm technology and very low prices of microchips.     

A Benchtop Method for Appending Protic Functional Groups to N-Heterocyclic Carbene Protected Gold Nanoparticles

The remarkable resilience of N-heterocyclic carbene (NHC) gold bonds has quickly made NHCs the ligand of choice when functionalizing gold surfaces. Despite rapid progress using deposition from free or CO₂-protected NHCs, synthetic challenges hinder the functionalization of NHC surfaces with protic functional groups, such as alcohols and amines, particularly on larger nanoparticles. Here, we synthesize NHC-functionalized gold surfaces from gold(I) NHC complexes and aqueous nanoparticles without the need for additional reagents, enabling otherwise difficult functional groups to be appended to the carbene. The resilience of the NHC−Au bond allows for multi-step post-synthetic modification. Beginning with the nitro-NHC, we form an amine-NHC terminated surface, which further undergoes amide coupling with carboxylic acids. The simplicity of this approach, its compatibility with aqueous nanoparticle solutions, and its ability to yield protic functionality, greatly expands the potential of NHC-functionalized noble metal surfaces.     

Nano-liquid chromatography-direct electron ionization mass spectrometry: improving performance by a new ion source adapter

A novel interface adapter has been designed to provide a new way of directly coupling a nano-liquid chromatograph to an electron ionization mass spectrometer. It connects the transfer capillary coming from the liquid chromatograph to the ionization chamber and can be easily screwed into the ion source. Liquid coming from the column passes through the heated adapter flow path and is vaporized. A continuous flow of new liquid pushes the vapor into the ionization chamber where it is ionized and continues on to the mass analyzer. The advantages of the new adapter are reduced ice formation inside the ion source and less clogging of the transfer capillary. Improvements achieved are demonstrated on the basis of caffeine and steroid analysis. The limits of detection of selected steroids are compared with and without the adapter. The adapter improves the detection limit of the system by a factor of 2 and precision from ≤15% to ≤9% relative standard deviation. No derivatization procedure is necessary before the analysis of small polar compounds. The resulting spectra are reproducible, easily interpretable, and database searchable. The new method is robust, delivers reproducible results, and provides a highly efficient alternative to existing methods in the field of pharmaceutical analysis.     

Der Wittelsbacher und der Hope‐Diamant

Diamonds are formed from carbon at high pressures and high temperatures in the inner part of the earth. Doping with very small amounts of boron leads to diamonds with blue colour. Two of the most famous historical blue diamonds, the Wittelsbach and Hope Diamond, were found in the Indian Kollur mine. The latter was brought to Europe by the French gem merchant Tavernier. Today it is displayed in the Smithsonian Institute. The Wittelsbach Diamond was for a long time in the possession of the House Wittelsbach until it was secretly sold in Antwerp in 1951. In 2008, it was purchased by auction by the jeweller Graff who recut the gem. In 2011, it was sold to an unknown buyer. As the Wittelsbach and the Hope diamond share origin and colour, it was assumed for a long time that both are pieces from a larger crystal. By optical investigation it was now shown that they have indeed some similar optical properties, but differ strikingly in other ones. Hence, they cannot originate from the same crystal.     

Objective Bayesian Model Selection in Generalized Additive Models With Penalized Splines

We propose an objective Bayesian approach to the selection of covariates and their penalized splines transformations in generalized additive models. The methodology is based on a combination of continuous mixtures of g-priors for model parameters and a multiplicity-correction prior for the models themselves. We introduce our approach in the normal model and extend it to nonnormal exponential families. A simulation study and an application with binary outcome is provided. An efficient implementation is available in the R package hypergsplines. Supplementary materials for this article are available online.     

The division problem for tempered distributions of one variable

We give a characterization, in one variable case, of those $C^{\infty }$ multipliers F such that the division problem is solvable in $S^{\prime }(\mathbb{R})$. For these functions $F\in O_M(\mathbb{R})$ we even prove that the multiplication operator $M_F(G)=FG$ has a continuous linear right inverse on $S^{\prime }(\mathbb{R})$, in contrast to what happens in the several variables case, as was shown by Langenbruch.     

Localization of acoustic sources in subsonic jets

The sound in the acoustic far–field of a round jet is generated by a multitude of unsteady flow structures with different length and time scales. Most likely, different components of the noise spectrum are created by different structures in the jet which emit sound in different directions. Based on Lighthill's acoustic analogy, we present a method for relating flow structures of the jet with far–field noise spectra and their associated directivity patterns. The method allows to determine what kind of noise (with respect to frequency and emission direction) is generated at a given streamwise location. We illustrate the method with numerical results for a round isothermal jet. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Stoffwechselprodukte von Mikroorganismen. 250. Mitteilung. Maduraferrin,ein neuartiger Siderophor aus Actinomadura madurae

Maduraferrin, a Novel Siderophore from Actinomadura madurae From a strain of Actinomadura madurae, a new siderophore was isolated. Maduraferrin is the Fe complex of an oligopeptide composed of salicylic acid, β-alanine, glycine, L -serine, N^δ-hydroxy-N^α-methyl-L -ornithine, and L -hexahydropyridazine-3-carboxylic acid. The complexing centers are a salicylamide moiety, a hydroxamic-acid group and an acid hydrazide group.