Bulk element concentrations of whole grain and element spatial distributions at the tissue level were investigated in wheat (Triticum aestivum) grain grown in Zn-enriched soil. Inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry were used for bulk analysis, whereas micro-proton-induced X-ray emission was used to resolve the two-dimensional localization of the elements. Soil Zn application did not significantly affect the grain yield, but did significantly increase the grain Ca, Fe and Zn concentrations, and decrease the grain Na, P and Mo concentrations; bulk Mg, S, K, Mn, Cu, Cd and Pb concentrations remained unchanged. These changes observed in bulk element concentrations are the reflection of tissue-specific variations within the grain, revealing that Zn application to soil can lead to considerable alterations in the element distributions within the grain, which might ultimately influence the quality of the milling fractions. Spatially resolved investigations into the partitioning of the element concentrations identified the tissues with the highest element concentrations, which is of utmost importance for accurate prediction of element losses during the grain milling and polishing processes.
F.04 Increase of the technological level
COBISS.SI-ID: 7578745Temperature dependence of D atom adsorption on polycrystalline tungsten was studied by in situ ion beam method Elastic Recoil Detection Analysis (ERDA). A new procedure named thermoadsorption (TA) was developed for this study, where the sample is first exposed to a deuterium atom beam at high temperature and then, while being continuously exposed to the atom beam, is slowly cooled down. H and D concentrations are determined during this cooling by ERDA. A stepwise increase of the surface areal density was observed starting from (1.2 ± 0.3) × 1015 D cm−2 at sample temperature around 750 K, to (2.2 ± 0.3) × 1015 D cm−2 when temperature was around 600–500 K and final increase to (6.8 ± 0.6) × 1015 D cm−2 when sample temperature was below 440 K. From this, three individual binding states were identified for the studied polycrystalline tungsten. We present a numerical model adequate to our experimental procedure which was developed by taking into account all relevant surface processes. The binding energies for desorption/adsorption were derived by modeling the TA data with the numerical model and were determined to be: 1.05 ± 0.06 eV, 1.7 ± 0.08 eV and )2.2 eV. Isotope exchange at 485 K sample temperature was also measured and modeled. An estimate of the reflection coefficient for 0.2 eV hydrogen atoms on polycrystalline W was obtained from modeling the isotope exchange data and was determined to be 0.96 ± 0.02.
F.05 Ability to launch new technological development cycle
COBISS.SI-ID: 26861095Understanding the mechanism(s) of polysulfide formation and knowledge about the interactions of sulfur and polysulfides with a host matrix and electrolyte are essential for the development of long-cycle-life lithium–sulfur (Li–S) batteries. To achieve this goal, new analytical tools need to be developed. Herein, sulfur K-edge X-ray absorption near-edge structure (XANES) and 6,7Li magic-angle spinning (MAS) NMR studies on a Li–S battery and its sulfur components are reported. The characterization of different stoichiometric mixtures of sulfur and lithium compounds (polysulfides), synthesized through a chemical route with all-sulfur-based components in the Li–S battery (sulfur and electrolyte), enables the understanding of changes in the batteries measured in postmortem mode and in operando mode. A detailed XANES analysis is performed on the different battery components (cathode composite, and separator). The relative amounts of each sulfur compound in the cathode and separator are determined precisely, according to the linear combination fit of the XANES spectra, by using reference compounds. Complementary information about the lithium species within the cathode are obtained by using 7Li MAS NMR spectroscopy. The setup for the in operando XANES measurements can be viewed as a valuable analytical tool that can aid the understanding of the sulfur environment in Li–S batteries.
F.06 Development of a new product
The Progress Report deals with results in X-ray and Auger spectroscopy that emerged from our efforts in the last few years. In the field of the high resolution X-ray spectroscopy we concentrate on the so-called tender 2-5 keV energy region. A high brilliance monochromatic X-ray beam @ID26 at ESRF synchrotron (Grenoble, France) coupled to our all-in-vacuum high resolution X-ray spectrometer of Johansson type with an off-Rowland target was found suitable for efficient experimentation with low density atomic and molecular targets, as in such spectrometer set-up practically no loss of spectral resolution occurs over target lengths as large as a few mm.
B.04 Guest lecture
COBISS.SI-ID: 27109159Recently we completed a construction of a cryostat at Jožef Stefan Institute (JSI) nuclear microprobe enabling us to analyze various types of biological samples in frozen hydrated state using micro-PIXE/STIM/RBS. Sample load-lock system was added to our existing setup to enable us to quickly insert a sample holder with frozen hydrated tissue samples onto a cold goniometer head cooled with liquid nitrogen inside the measuring chamber. Cryotome-cut slices of frozen hydrated plant samples were mounted between two thin silicon nitride foils and then attached to the sample holder. Sufficient thermal contact between silicon nitride foils and sample holder must be achieved, as well as between the sample holder and the cold goniometer head inside the measuring chamber to prevent melting of the samples. Matrix composition of frozen hydrated tissue is consisted mostly of ice. Thinning of the sample as well as water evaporation during high vacuum and proton beam exposure was inspected by the measurements with RBS and STIM method simultaneously with micro-PIXE. For first measuring attempts a standard micro-PIXE configuration for tissue mapping was used with proton beam cross section of 1.2 × 1.2 μm2 and a beam current of 100 pA. The temperature of the cold goniometer head was kept below 130 K throughout the entire proton beam exposure. First measurements of thin plant tissue samples in frozen hydrated state show minute sample degradation during the 10 h period of micro-PIXE measurements.
F.01 Acquisition of new practical knowledge, information and skills
COBISS.SI-ID: 2762063