Spin locking at the apex of nano-scale platinum tips

Nanostructures based on platinum, such as small clusters or STM-tips, often exhibit an atomistic structure that relies upon one or very few strongly under-coordinated platinum atoms. Here, we analyze a paradigmatic example, an apex atom on a pyramidal platinum cluster employing the density functional theory. We show that such a pristine platinum tip exhibits a spin polarization of the apex atom with a remarkable robustness. Due to a depletion of the projected density of states at the apex position, the apex-magnetization is efficiently locked to about 0.6$\mu_\text{B}$

Diergeneesmiddelen in aquacultuur

De Nederlandse visteelt heeft nog niet de beschikking over toegestane diergeneesmiddelen, terwijl de noodzaak om bepaalde middelen te gebruiken in de praktijk bestaat. Deze middelen zijn met name: flumequine, mebendazole, oxolinezuur, oxytetracycline, praziquantel en trimethosulfmix. Wat op dit moment niet duidelijk is is de farmacokinetiek van deze middelen voor de vissoorten die in Nederland gekweekt worden. Deze informatie is van belang om te voorkomen dat residuen van de geneesmiddelen in voor consumptie bestemde visproducten terecht komen. Om meer inzicht te krijgen in bestaande farmacokinetische data voor de meest gebruikte middelen is een literatuuronderzoek uitgevoerd

Comparison of quantification methods for the analysis of polychlorinated alkanes using electron capture negative ionization mass spectrometry.

Four quantification methods for short-chain chlorinated paraffins (SCCPs) or polychlorinated alkanes (PCAs) using gas chromatography electron capture negative ionisation low resolution mass spectrometry (GC-ECNI-LRMS) were investigated. The method based on visual comparison of congener group patterns of external standards used for quantification and fish samples was very sensitive for the choice of the quantification standard. Two other methods used the existing relation of the response factors with the chlorine content of SCCP mixtures for quantification. Results from the three methods above deviated from nominal values less than 20%. This was ~50% when individual PCA standards were applied for quantification of SCCPs. The deviation is probably caused by the fact that only C10 carbon chain length standards with 5-9 chlorine atoms could be used. However, quantification using individual PCA standards is a promising method provided more standards will become commercially available. The clear advantage is that the standards are defined, which makes quantification comparable between different laboratories. Application of all four quantification methods to the analysis of four different fish samples gave results that agreed with the median values within ±40

Evaluation of the effect of De-icing materials on soil quality in selected areas

Bakalářská práce se zabývá vlivem chloridu sodného, jako rozmrazovacího posypového materiálu, na kvalitu půd kolem komunikací v Bruntále. Teoretická část se zabývá vlastnostmi půdy, přírodními poměry zájmové oblasti, prostředky a technologiemi zimní údržby s možným vlivem na životní prostředí a vybraným fyzikálním a chemickým parametrům stanovení, kterými se práce bude zabývat ve své praktické části. V praktické části bakalářské práce je popsána metodika odběru vzorků, zpracování vzorků, výsledky a zhodnocení vlivu rozmrazovacího posypového materiálu na kvalitu půd a životní prostředí ve vybraných oblasti.The bachelor thesis deals with the impact of sodium chloride, as a de-icing material, on the quality of soils around roads in Bruntál. The theoretical part deals with soil properties, natural conditions of the area of interest, means and technologies of winter maintenance with possible environmental impact and selected physical and chemical parameters of determination, which will be dealt with in the practical part of the thesis. The practical part of the bachelor thesis describes the sampling methodology, sample processing, results and evaluation of the effect of de-icing material on soil and environmental quality in the selected area.546 - Katedra environmentálního inženýrstvídobř

X-ray diffracted intensity for double reflection channel cut Ge monochromators at extremely asymmetric diffraction conditions

The width and the integrated intensity of the 220 x-ray double diffraction profile and the shift of the Bragg condition due to refraction have been measured in a channel cut Ge crystal in an angular range near the critical angle of total external reflection. The Bragg angle and incidence condition were varied by changing the x-ray energy. In agreement with the extended dynamical theory of x-ray diffraction, the integrated intensity of the double diffraction remained almost constant even for grazing incidence condition very close to the critical angle C for total external reflection. A broadening of the diffraction profile not predicted by the extended theory of x-ray diffraction was observed when the Bragg condition was at angles of incidence lower than 0.6?. Plane wave topographs revealed a contrast that could be explained by a slight residual crystal surface undulation of 0.3 degrees due to the etching to remove the cutting damage and the increasing effect of refraction at glancing angles close to the critical angle. These findings confirm that highly asymmetric channel cut Ge crystals can work as efficient monochromators or image magnifiers also at glancing angles close to the critical angle and that the main limitation is the crystal surface preparation

Environmental Levels and Trends of 1,2-dichloroethane, vinyl chloride and chloroform in water, sediment and biota for the European and Arctic regions: literature study

Data on concentrations of chloroform, 1,2-dichloroethane and vinyl chloride in European and Arctic waters, sediments and biota were collected from scientific literature and monitoring programmes for the period 1980–2005 and are presented in this report

Chemical/biological analyses of harbour porpoise samples to indentify contaminants in the food chains

One of the main objectives of the “Koploper” project “Identificatie van mogelijke probleemstoffen in voedselketens en toppredatoren” is to identify possible causes of the increasing number of harbour porpoises that are stranded on the Dutch coast. In order to find out whether chemical contamination could cause the increased stranding, Deltares has contracted IMARES to analyse main organohalogenated contaminants in the harbour porpoises found stranded during year 2006

Het concentreren en opwerken van waterige monsters volgens de XAD procedure

In opdracht van RWS-RIZA is het project “Het concentreren en opwerken van waterige monsters volgens de XAD procedure” uitgevoerd. De XAD procedure is uitgevoerd volgens een protocol dat is gebaseerd op methoden ontwikkeld bij het RIVM, Laboratorium voor Ecotoxicologie te Bilthoven. Daarna zijn de waterige monsters naar TNO IMARES in Den Helder gegaan voor beoordeling van de toxiciteit