Stable doubly charged positive molecular ions formed by direct attachment of alpha particles to HCN and HNC

The existence of [HeNCH](2+) and [HeCNH](2+) is examined by reliable high-level ab initio methods. It is shown that both species are metastable with respect to the proton loss process, but the activation barriers are high enough to accommodate several resonant states. Their estimated lifetimes are practically infinite for v<3, implying that the attachment of alpha particles to HNC and HCN yields kinetically stable dications. This could be an important factor in the cyanide chemistry in interstellar and comet environments.     

Surface freezing and a two-step pathway of the isotropic-smectic phase transition in colloidal rods

We study the kinetics of the isotropic-smectic phase transition in a colloidal rod/polymer mixture by visualizing individual smectic layers. First, we show that the bulk isotropic-smectic phase transition is preceded by a surface freezing transition in which a quasi-two-dimensional smectic phase wets the isotropic-nematic interface. Next, we identify a two-step kinetic pathway for the formation of a bulk smectic phase. In the first step a metastable isotropic-nematic interface is formed. This interface is wetted by the surface-induced smectic phase. In the subsequent step, smectic layers nucleate at this surface phase and grow into the isotropic bulk phase.     

Verallgemeinerung eines Satzes von B. Huppert und J. G. Thompson

Ohne Zusammenfassung     

Endliche Gruppen mit lauter nilpotenten zweitmaximalen Untergruppen

Ohne ZusammenfassungHerrnReinhold Baer zum 60. Geburtstag am 22. Juli 1962 gewidmet     

Red clover (<Emphasis Type="Italic">Trifolium pratense</Emphasis> L.) honey: volatiles chemical-profiling and unlocking antioxidant and anticorrosion capacity

Headspace solid-phase micro-extraction (HS-SPME) and ultrasonic solvent extraction (USE) were used for red clover honey volatiles extraction. The extracts were analysed using gas chromatography and mass spectrometry (GC-MS). Lilac aldehyde isomers dominated in the headspace (individual range from 7.6 % to 21.4 %) followed by phenylacetaldehyde (10.1–31.2 %) and benzaldehyde (7.0–15.7 %). Higher aliphatic alcohols and hydrocarbons were the predominant constituents of the honey extracts. The honey and its extracts exhibited rather weak anti-radical activity (DPPH assay) and total antioxidant activity (FRAP assay). On the other hand, the honey’s inhibitive properties towards the corrosion of AA 2017A alloy in NaCl solution (potentiodynamic polarisation and potentiostatic pulse measurements) revealed the honey to be a very good anodic inhibitor (efficiency up to 76 %) while the honey extracts (USE) showed better inhibition efficacy.     

Derivation and Justification of the Models of Rods and Plates From Linearized Three-Dimensional Micropolar Elasticity

In this paper we derive and mathematically justify models of micropolar rods and plates from the equations of linearized micropolar elasticity. Derivation is based on the asymptotic techniques with respect to the small parameter being the thickness of the elastic body we consider. Justification of the models is obtained through the convergence result for the displacement and microrotation fields when the thickness tends to zero. The limiting microrotation is then related to the macrorotation of the cross–section (transversal segment) and the model is rewritten in terms of macroscopic unknowns. The obtained models are recognized as being either the Reissner–Mindlin plate or the Timoshenko beam type.