Structure determination of Au on Pt(111) surface:LEED, STM and DFT Study

Low-energy electron diffraction (LEED), scanning tunneling microscopy (STM) and density functional theory (DFT) calculations have been used to investigate the atomic and electronic structure of gold deposited (between 0.8 and 1.0 monolayer) on the Pt(111) face in ultrahigh vacuum at room temperature. The analysis of LEED and STM measurements indicates two-dimensional growth of the first Au monolayer. Change of the measured surface lattice constant equal to 2.80 Å after Au adsorption was not observed. Based on DFT, the distance between the nearest atoms in the case of bare Pt(111) and Au/Pt(111) surface is equal to 2.83 Å, which gives 1% difference in comparison with STM values. The first and second interlayer spacing of the clean Pt(111) surface are expanded by +0.87% and contracted by −0.43%, respectively. The adsorption energy of the Au atom on the Pt(111) surface is dependent on the adsorption position, and there is a preference for a hollow fcc site. For the Au/Pt(111) surface, the top interlayer spacing is expanded by +2.16% with respect to the ideal bulk value. Changes in the electronic properties of the Au/Pt(111) system below the Fermi level connected to the interaction of Au atoms with Pt(111) surface are observed

Growth and characterisation of metal alloy and metal oxide surfaces

Optimisation of epitaxial anatase TiO2 thin films grown on LaAlO3(001) -substrates was performed using ultra-high vacuum based pulsed laser deposition -(PLD) and studied by in-situ reflection high-energy electron diffraction (RHEED). In -addition, ex-situ X-ray diffraction (XRD), atomic force microscopy (AFM), and -scanning transmission electron microscopy (STEM) were performed to characterise -the bulk properties of these thin films. The deposited TiO2 thin film is demonstrated -to have anatase phase and bonded directly to the LaAlO3(001) substrate. In a separate -ultra-high vacuum system low-energy electron diffraction (LEED) and scanning -tunnelling microscopy (STM) measurements were performed and a well-ordered twodomain -(1´4) and (4´1) reconstruction of anatase surface was observed. Analysis of -the STM measurements indicates the coexistence of atomic steps of both 2.5 Å and 5.0 -Å, confirming the existence of two TiO2 domains. The atomic resolution STEM -images reveal that the TiO2/LaAlO3 interface to be terminated with LaO layer and that -the anatase-TiO2 reconstruction was found to be stable during the film growth. Low-energy electron diffraction (LEED), scanning tunneling microscopy (STM) -and density functional theory (DFT) calculations have been used to investigate the -atomic and electronic structure of gold deposited (between 0.8 and 1.0 monolayer) on -the Pt(111) face in ultrahigh vacuum at room temperature. The analysis of LEED and -STM measurements indicates two-dimensional growth of the first Au monolayer. -Change of the measured surface lattice constant equal to 2.80 Å after Au adsorption -was not observed. Based on DFT, the distance between the nearest atoms in the case -of bare Pt(111) and Au/Pt(111) surface is equal to 2.83 Å, which gives 1% difference -in comparison with STM values. The first and second interlayer spacing of the clean -Pt(111) surface are expanded by +0.87% and contracted by −0.43%, respectively. The -adsorption energy of the Au atom on the Pt(111) surface is dependent on the adsorption -position, and there is a preference for a hollow fcc site. For the Au/Pt(111) surface, the -top interlayer spacing is expanded by +2.16% with respect to the ideal bulk value. -Changes in the electronic properties of the Au/Pt(111) system below the Fermi level -connected to the interaction of Au atoms with Pt(111) surface are observed. Detailed structural properties of the Pt3Ti(111) surface have been studing with -the use of ab initio density functional theory calculations and scanning tunelling -microscopy measurements. The DFT calculations show that the atoms composition of -the second and third atomic layer have influence upon the top surface of the Pt3T

Interrelationships between Morphological, Densitometric and Mechanical Properties of Eggs in Japanese Quails (Coturnix Japonica)

Eggshell quality in birds results from mineral density and composition determining its mechanical endurance. The aim of the study was to determine interrelationships between morphological, densitometric and mechanical properties of eggs in Japanese quails. Twenty four eggs randomly collected from 17-week-old quails were subjected to morphological, denstiometric and mechanical evaluation using dual-energy X-ray absorptiometry (DEXA), quantitative computed tomography (QCT) and three-point bending test. Weight, height and width of eggs were positively correlated with the densitometric parameters obtained using DEXA (egg mineral density (EMD) and egg mineral content (EMC)) and QCT (total egg volume (TEvol) and total eggshell volume (TESvol)). Positive correlations were stated between TEvol and TESvol (r＝0.52; P<0.05) and EMD and EMC r＝0.83; P<0.05). Egg mineral density revealed positive correlations with TEvol and mean volumetric eggshell mineral density (MvESMD), while EMC was positively correlated with TEvol, TESvol and MvESMD (all P<0.05). Eggshell breaking strength was positively correlated with MvESMD (r＝0.53; P<0.05) and negatively correlated with eggshell thickness (r＝−0.50; P<0.05). In conclusion, the results obtained in this study showed numerous interrelationships between morphological, densitometric and mechanical properties of eggs in Japanese quails. Both DEXA and QCT were shown to be valuable tools for evaluation of whole egg and eggshell quality with superior prognostic value of QCT for eggshell mechanical endurance prediction. The elaborated experimental model may serve for further investigations on physiological, pharmacological, environmental, nutritional and toxicological factors influencing egg quality

Lacustrine, fluvial and slope deposits in the wetland shore area in Serteya, Western Russia

The article presents the results of a study on sediment deposition processes in the palaeolake shore zone, at the multilayered Serteya II archaeological site in Western Russia. In recent years, geomorphological, palaeopedological and palaeoecological research was undertaken in strict cooperation with archaeological fieldwork. The Serteya II site occupies a substantial area of a kame terrace and biogenic plain within a palaeolake basin. From an archaeological point of view, the site is represented by few Mesolithic artefacts, but mostly by remnants of hunter–gatherer–fisher communities attributed in the Russian scientific tradition to the Neolithic period and dated from 6300 BC to 2000 BC. Later, the area was used by people in the Bronze Age, Early Iron Age and Early Middle Ages. The integration of archaeological and multidisciplinary palaeoenvironmental research allowed the natural and human induced deposition of mineral-organic and minerogenic sediments to be reconstructed, as well as the development of structures in the lake shore zone. The changes from lacustrine to fluvial system were documented and the human impact is recorded mostly in the acceleration of slope processes