Interaction of MEV atomic ions with molecular solids: Ion track structure and sputtering phenomena

Recent results obtained in our research groups from studies of the interactions of swift, heavy atomic ions with molecular solids are concisely outlined. The focus is on material ejection (sputtering) and surface track formation. The experimental techniques employed include time-of-flight mass spectrometry, energy analysis, collection and analysis of sputtered material, and scanning force microscopy. Characteristics of the sputtering process probed include the sputtering yield, radial and axial velocity distributions, angular distributions, and surface track morphology. Besides reviewing and correlating experimental results, we also emphasize the common quasi-thermal origin of pressure-pulse/hydrodynamic and evaporative spike sputtering models.     

Specific features of the structure and electrical conductivity of the magnetically ordered oxide (La0.9Sr0.1)(Fe0.8Mg0.2)O3?y

The structure of the (La_0.9Sr_0.1)(Fe_0.8Mg_0.2)O_{3− y} oxide is investigated using neutron diffraction at temperatures of 10, 295, 500, 700, and 1000 K. The results of the structure refinement are in good agreement with the experimental data on the electrical conductivity and confirm the inference that the oxidation state of iron cations is higher than 3+ and that the structure of the compound is antiferromagnetically ordered at temperatures below 500 K. Original Russian Text ? S.A. Ivanov, G.M. Kaleva, A.V. Mosunov, E.D. Politova, S.-G. Eriksson, 2008, published in Kristallografiya, 2008, Vol. 53, No. 1, pp. 69–75.     

One‐pot enzymatic route to tetraallyl ether functional oligoesters: Synthesis,UV curing,and characterization

An enzymatic one‐pot route in bulk was used to synthesize tetraallyl ether (tAE) functional oligomers based on divinyl adipate, 1,4‐butanediol and trimethylolpropane diallyl ether. By using lipase B from Candida antarctica as catalyst and varying the stoichiometric ratio of monomers, it was possible to reach targeted molecular weights (from 1300 to 3300 g mol^?1) of allyl‐ether functional polyesters. The enzyme catalyzed reaction reached completion (>98% conversion based on all monomers) within 24 h at 60 °C, under reduced pressure (72 mbar) resulting in ～90% yield after filtration. The tAE‐functional oligoesters were photopolymerized, without any purification other than removal of the enzyme by filtration, with thiol functional monomers (dithiol, tetrathiol) in a 1:1 ratio thiol‐ene reaction. The photo‐initiator, 2,2‐dimethoxy‐2‐phenylacetophenone, was used to improve the rate of reaction under UV light. High conversions (96–99% within detection limits) were found for all thiol‐ene films as determined by FT‐Raman spectroscopy. The tAE‐functional oligoesters were characterized by NMR, MALDI, and SEC. The UV‐cured homopolymerized films and the thiol‐ene films properties were characterized utilizing DSC and DMTA. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Uranium and plutonium containing particles in a sea sediment sample from Thule, Greenland

Particles composed of radioactive materials and probably originating from US nuclear weapons were identified in sea sediment samples collected from Thule, Greenland, in 1997. The weapons were destroyed close to the Thule Air Base in 1968 in an aeroplane crash, which dispersed radioactive materials in the environment. The presence of particulate radioactive materials in the sediment samples was revealed by combining gamma-spectrometry and autoradiography. Isolation and separation of a radioactive particle from a bulk sample were performed using autoradiography, phosphor plate imaging and scanning electron microscopy. Using X-ray microanalysis as well as alpha and beta activity analysis, U and weapons-grade Pu were detected in the granular, brittle particle.     

Rapid analysis of peptide toxins in cyanobacteria

A quick and easy-to-perform method for routine analysis of cyanobacterial (blue-green algal) peptide toxins is proposed. The toxins are analysed by means of high-performance liquid chromatography using a recently developed internal surface reversed-phase column. The sample clean-up work is minimized and the total analysis time is thus shortened considerably compared to previously described methods.     

A comment on classical rainbow angles for atom-atom scattering

The dependence of the rainbow angle on the depth of the potential well, the equilibrium distance, andthe force constant of the potential are discussed for several potential functions.     

Solvent delivery in the new application areas of high-performance liquid chromatography

Summary The development of new column packings for biological macromolecules, as well as the techniques for handling micropacked columns, sets new demands on solvent delivery systems for HPLC. The main implications of these developments with respect to pump design are discussed and the evaluation of a solvent delivery system (pump and gradient programmer) optimized for these purposes is presented.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Determination of dγ/dT for water by means of a differential technique

The temperature derivative of the surface tension of water has been measured by means of the Wilhelmy method using an electrobalance and a differential technique. No anomalies were observed; −dγ/dT was found to be a slowly increasing linear function of T within the temperature range 5–40°C.