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<p>In the winter of 2017 three undisturbed sediment cores were retrieved from the Szemes Basin of Lake Balaton. The sediments were sampled for AMS <sup>14</sup>C dating and we used 8 of the radiocarbon dates for age-depth modelling. Based on this, the investigated sediment sequence covers the entire Holocene and Late Glacial period and the bottom of the sediment is ca. ~16,000 cal yr BP old. X-ray fluorescence spectrometry (XRF) was used to reconstruct rapid changes in the element content of the lake sediment. The evaluation of the measured results makes it possible to reconstruct the changes in the discharge environment and lake water level that can be related to the climate and human impact. Based on the data, two major evaporation events can be observed at 5500 BP and 8100 BP. These results were also verified by oxygen isotope studies. To reconstruct the energy of the deposition environment, particle size analysis was performed. The obtained results confirmed that river sediments are common at the bottom of Lake Balaton sediments, while biogenic carbonate dominates in the upper, Holocene part of the sediment core. To identify each mineral phase in the sediment, X-ray diffraction (XRD) studies were used to determine the ratio of calcite to Mg-calcite. Based on our XRF measurements, focusing primarily on quantitative changes in magnesium and calcium, transmission electron microscopy (TEM) studies were performed, mainly in the Mg enrichment layer around 8100 BP. The precipitation of biogenic carbonate in Lake Balaton is still taking place, mainly in the form of calcite and Mg-calcite. Their relative proportions strongly depend on the Mg saturation of the water and the substrates on which they are separated. From our results we can draw conclusions about the possible previous deeper phases of the lake and the evaporation conditions of the water. The data obtained from transmission electron microscopy shows a good agreement with the results of the XRF measurement, the proportion of Mg-calcite increases around 8100 BP that likely indicate drier climatic conditions connectable to the well know 8.2 ka cal BP climatic reversal.</p>

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Interfacial intermetallic compounds (IMC) play an important role in Sn-Cu lead-free soldering. The size and morphology of the intermetallic compounds formed between the lead-free solder and the Cu substrate have a significant effect on the mechanical strength of the solder joint.In the soldering process of Sn-Cu alloys, Cu 6 Sn 5 intermetallic compounds are formed. The complex structural behaviour of Cu 6 Sn 5 IMC is temperature-and composition-dependent and it is long since subject to scientific research. The Cu 6 Sn 5 phase basically exists in two crystal structures: hexagonal η-Cu 6 Sn 5 (at temperatures above 186 • C) and monoclinic η'-Cu 6 Sn 5 (at lower temperatures). In the presence of Ni in the solder, the η-η' transformation does not occur, therefore, the η-Cu 6 Sn 5 phase remains stable.In this study the role of Ni in the (Cu,Ni) 6 Sn 5 intermetallic compound in Sn-Cu lead-free solders was examined. Sn-Cu alloys with different Cu content (0.5 to 1 mass%) were modified through Ni addition. The morphology of the intermetallic compounds of the modified Sn-Cu alloys was investigated by optical microscopy (OM) and scanning electron microscopy (SEM), the IMC phases were examined with X-ray diffraction method (XRD).