Measurement of storage time, estimation of ion number and study of absorption line profile in a Paul trap

Europium (Eu⁺) ions were confined in a Paul trap and detected by non-destructive method. Storage time of Eu⁺ ions achieved in vacuum was improved by orders of magnitude employing buffer gas cooling. The experimentally detected signal was fitted to the ion response signal and the total number of ions trapped was estimated. It is found that the peak signal amplitude as well as the product of FWHM and the peak signal amplitude is proportional to the total number of trapped ions. The trapped ion secular frequency was swept at different rates and its effect on the absorption line profile was studied both experimentally and theoretically.     

The CO fundamental-band laser as secondary frequency standard at 5 µm

We present a very high-resolution heterodyne spectrometer based on a CO laser which operates down to fundamental-band transitions of the molecule. This allows us to detect saturated absorption signals on these transitions at very low pressure (0.4 Pa) and laser intensity (< 1 mW/cm²), yielding a linewidth of about 250 kHz. With the CO fundamental-band laser stabilized to these saturation signals we have measured the transition frequencies of the fundamental bands of three isotopic species to an accuracy of typically 20 kHz (v/v 3 × 10^–10), referenced to the CO₂ frequency standard. Together with additional frequency measurements of the first hot bands, these provide the first heterodyne frequency data of sub-Doppler accuracy for transitions in low lying bands of CO. They now represent the most accurate secondary frequency standard in the spectral region around 5 µm (60 THz).     

Effects of Salt on the Orientational Order in Decylammonium Chloride/Ammonium Chloride/Water Systems

The effect of NH₄Cl on the temperature dependence of deuterium oxide splitting (water order) and proton line width (surfactant order) in decylammonium chloride (DACl), D₂O systems is reported. The molar ratio of DACl to D₂O was held constant at .085 and the molar ratio of NH₄Cl to D₂O was varied from .012 to .029. We find for the above concentration ranges that in the nematic range the relative temperature dependence of the D₂O splitting is little affected by changes on salt concentration. The slopes of the proton line widths as a function of temperature decrease with increasing salt concentration. The results are compared with earlier data on salt effects on order obtained with the disodium cromoglycate system.     

Ergebnisse der Untersuchung Geologischer Standards

Using instrumental neutron activation analysis 18 elements are determined in 9 standard rocks of the central geological institut of the GDR. The results are compared with certified values.      

Correction: Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity

After the publication of the work entitled "Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity", by Kozlowski et al., BMC Biochemistry 2011, 12:29, we found that the legends to Figures 2 to 5 contain serious mistakes that compromise the comprehension of the work. This correction article contains the correct text of the legends to Figures 2 to 5.     

The Structure of Lyotropic Nematic Decylammoniumchloride and Bromide Systems by PMR of Monomethyltin Complexes and by Microscopic Studies

The pmr spectrum of methyltintrichloride in aqueous micellar solutions of decylammoniumchloride and KCl, and of decylammoniumbromide and KBr was investigated. The large scalar SnH couplings of 134.0 Hz and 130.2 Hz respectively indicate the formation of six coordination complexes CH₃SnCl₅ ^{- -} and CH₃SnBr₅ ^{- -} in the micellar solutions, but the geometrical structure of the CH₃Sn moiety is little affected by the complex formation. The complexes orient with their symmetry axis preferably parallel to the nematic axis.

In microscopic studies on selected mixtures a reversible first order phase transition was observed between nematic and isotropic micellar solution at about 45°C and a reversible transition between a lamellar smectic phase and the nematic phase at about 30°C that appears to be of second order. The optical observations and the orientation of the methyltin complex indicate that the nematic solutions have micelles of a bilayer structure.     

On the structure and the physical properties of micellar nematics

Summary Micellar nematic systems and some of their physical properties are reviewed. The effect of additives is demonstrated and discussed for selected surfactant systems with respect to phase stability and the induction of cholesteric states. Experimental results on physical properties of micellar nematics with emphasis on curvature elasticity are summarized and related to the micellar structure. Paper presented at the ?Meeting on Lyotropics and Related Fields?, held in Rende, Cosenza, September, 13–18, 1982.