Unveiling point defects in titania mesocrystals: a combined EPR and XPS study

Titania mesocrystals, prepared using a polyethylene template, were studied by a combination of electron microscopy, XPS and EPR techniques. The electronic structure and local environment of point defects in the TiO2 mesocrystals were deduced from experimental and simulated EPR data. The Ti3+/F centers and oxygen defects were shown to be the most photosensitive. The presence of carbon radicals was also demonstrated. Since the point defects govern TiO2 photosensitivity and photocatalytic activity in the visible spectral range, the data obtained provide new insights into photocatalytic reactions engineering using titania mesocrystal

Dynamics of photogenerated charge carriers in TiO2 /MoO3, TiO2 /WO3 and TiO2 /V2O5 photocatalysts with mosaic structure

Titania is a widely used photocatalytic material possessing such advantages as low cost and high reactivity under the ultraviolet light illumination. However, the fast recombination of photoexcited charge carriers limits its application. Herein, we have synthesized original nanomaterials with mosaic structures that exhibited well-defined heterojunctions and new properties. Using SEM, XRD, EPR spectroscopy, photocatalytic measurements, and photoinduced pathphysiological activity of these photocatalysts, we studied the processes of charge carrier accumulation in TiO2 /MoO3, TiO2 /WO3, and TiO2 /V2 O5 under in situ UV illumination with emphasis on the charge exchange between energy levels of these nanosized semiconductors. It is shown that the accumulation of photoinduced charges occurs in two forms (i) filled electron traps corresponding to Ti4+ /Ti3+ levels and (ii) Mo5+ centers, both forms contributing to the photoinduced biocide activity of the samples. This work demonstrates that light exposure of heterostructure photocatalysts with mosaic surfaces produces different types of charge-trapping centers capable of interacting with molecular oxygen yielding peroxo species, which provide long-life light-induced ”self-cleaning” behavior. Such photoaccumulating materials open new opportunities in developing light-driven self-sterilization structures exhibiting a prolonged bactericidal effect up to 10 h after stopping light exposure. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Paramagnetic properties of carbon-doped titanium dioxide

This paper reports the experimental results on paramagnetic properties of carbon-doped titanium dioxide. The electron paramagnetic resonance study of the samples has been carried out both in dark and under illumination. The nature of defects and their dynamics under illumination of carbon-doped TiO(2) samples is discussed

Genderové rozdíly na trhu práce: Případ nerovnosti?

1 Abstrakt Fenomén rozdílů v odměňování žen a mužů je nyní již několik desetiletí po- drobně zkoumán a dosavadní výzkum je rozsáhlý a různorodý. V této diplomové práci shromažďujeme, shrnujeme a sumarizujeme empirická zjištění napří˚c nedáv- nou literaturou ohledně rozdílů v odměňování žen a mužů pomocí meta-regresní analýzy. Náš vzorek pokrývá téměř 20 let nejnovějšího výzkumu a 35 rozv- inutých zemí. Výsledky metagrese vysvětlují téměř 90 procent variace mezi jednotlivými studiemi a nazna˚cují, že největší dopad na odhadované rozdíly v odměňování žen a mužů má nekontrolování po˚ctu odpracovaných hodin. Kromě toho se ukazuje, že stav publikace původní studie má velký vliv na odhadovaný rozdíl v odměňování žen a mužů. Naopak empirická zjištění nazna˚cují, že studie přidružená k ur˚cité instituci podporující feminismus nebo rovnost pohlaví mají tendenci přeceňovat rozdíl v odměňování žen a mužů. Klasifikace JEL J16, J31, J71 Klí˚cová slovaa rozdíl v odměňování žen a mužů, diskrimi- nace Název práce Meta-analytický přístup k rozdílům v odměňování žen a mužů: případ diskrim- inace?1 Abstract The phenomenon of the gender pay gap has now been vastly examined for sev- eral decades and the research to date is extensive and diverse. In the thesis at hand, we accumulate, review and summarize empirical findings across the recent literature on the gender pay gap by means of meta-regression analysis. Our sample covers almost 20 years of the latest research and 35 developed coun- tries. The meta-regression results explain almost 90 percent of the study-to- study variation and suggest that the largest impact on the estimated adjusted gender pay gap results from not controlling for hours worked. Furthermore, the publication status of the original study is shown to have a large downward impact on the estimated gender pay gap. Conversely, the empirical findings suggest that a study affiliated with a certain institution promoting feminism or gender equality tend to overestimate the adjusted gender pay gap. JEL Classification J16, J31, J71 Keywords gender pay gap, discrimination Title A Meta-Analytic Approach to Gender Pay Gap: A Case of Discrimination?Institut ekonomických studiíInstitute of Economic StudiesFaculty of Social SciencesFakulta sociálních vě

Art as a Financial Investment: Estimation of Art Returns and Portfolio Diversification

The thesis at hand examines risk, return and portfolio diversification oppor- tunities of the art market. In order to analyse price dynamics at the peculiar and unique art market scene and provide a reader with a basic understanding of the requirements for undertaking investment in this field several trends dominating in the art market abreast with the main art price determinants and risks are investigated. Based on the repeat sales data encompassing the period from 2000 to 2015, the art price indices have been estimated using both standard and three-stage weighted methods. Beyond a standard risk and return analysis of various art sectors compared with traditional invest- ment vehicles, this thesis also focuses on the performance of art with respect to the investment horizon. We conclude that longer holding period may be more beneficial than shorter one in terms of both return per unit of risk and costs per unit of time. However, in common with the literature in this area, the results suggest that the risk and return characteristics of art are inferior to the risk and return characteristics of financial assets and despite the low levels of correlation we have found no support for the inclusion of art in the mixed-asset portfolio. JEL Classification C13, C41, C61, D43, D44, G11, G14, Z11 Keywords art;..

A Meta-Analytic Approach to Gender Pay Gap: A Case of Discrimination?

1 Abstract The phenomenon of the gender pay gap has now been vastly examined for sev- eral decades and the research to date is extensive and diverse. In the thesis at hand, we accumulate, review and summarize empirical findings across the recent literature on the gender pay gap by means of meta-regression analysis. Our sample covers almost 20 years of the latest research and 35 developed coun- tries. The meta-regression results explain almost 90 percent of the study-to- study variation and suggest that the largest impact on the estimated adjusted gender pay gap results from not controlling for hours worked. Furthermore, the publication status of the original study is shown to have a large downward impact on the estimated gender pay gap. Conversely, the empirical findings suggest that a study affiliated with a certain institution promoting feminism or gender equality tend to overestimate the adjusted gender pay gap. JEL Classification J16, J31, J71 Keywords gender pay gap, discrimination Title A Meta-Analytic Approach to Gender Pay Gap: A Case of Discrimination

Comparative Study: Catalytic Activity and Rhodamine Dye Luminescence at the Surface of TiO2-Based Nanoheterostructures

Nanoheterostructures based on titanium, molybdenum, tungsten, and vanadium nanooxides with symmetric crystal structures, morphologies and high photocatalytic activity in under illumination by visible light, have been synthesized and studied. Microscopy, optical spectroscopy, and electron-spin resonance techniques were used. The asymmetric separation of photo-generated holes and electrons between different nanooxides in their nanoheterostructures suppresses their recombination. Using the method developed by the authors and based on ESR spectroscopy, the energy levels of the active centers inside the band gaps of the studied samples were found. We have shown, for the first time, that under illumination of nanoheterostructures under asymmetric conditions with adsorbed rhodamine dye at the dye-absorption wavelength (500 nm), photocatalytic reactions are mainly determined by light absorption by the nanostructures themselves, and not by energy transfer from the dye. This important result shows that high photocatalytic activity of materials with symmetric crystal structures is the primary criterion for creating energy-efficient photocatalysts. The results will be useful for the development of energy-efficient catalytic devices based on various combinations of metal nanooxides

Microelements in soils of forest-steppe sequent series in central part of Tobol-Ishim interfluve

The relevance of the research. Features of distribution and accumulation of trace elements including heavy metals in soils of agricultural landscapes is one of the most important directions of research in soil science, agricultural chemistry and geoecology. These studies have a high relevance for the southern part of Tyumen region which is characterized by a strong agricultural specialization. Exploration of main features and factors of trace elements distribution in soils of agricultural landscapes can be important for the complex ecological and geochemical assessment of the territory, the refinement of the regional background levels of pollutants in soils, for development of special measures aimed for reduction of environmental risks and improvement of the quality of agricultural products. The main aim of the study is to analyze the main geochemical features of distribution and accumulation of several trace elements (Ti, Cr, Mn, Ni, Co Cu, Zn, Pb, Sr) in soils of agricultural landscapes located within the forest-steppe zone of Tobol-Ishim interfluve, depending on the differences in particle size distribution, humus content, pH values and position in the relief. The methods used in study: field soil and landscape-geochemical studies, determination of pH values in soil-water suspension, particle size distribution analysis using pyrophosphate method (with a microprobe analyzer), definition of microelements total concentrations using TXRF method, determination of humus content by the Tyurin method, statistical processing of the data. The results. The author has investigated the content and distribution of Ti, Cr, Mn, Ni, Co Cu, Zn, Pb, and Sr in soils of agricultural landscapes for the territory of Tobol-Ishim interfluve. The data may indicate that soils of the central part of Tobol-Ishim interfluve are enriched in Cu, Pb, Co and depleted in Ni, Zn, Sr, Mn compared to the average content in soils and soil-forming rocks of the south of Western Siberia. It was revealed that soils of the plot, despite the provision in relief, are low-contrast in particle size distribution, and this soil attribute has virtually no effect on the distribution of trace elements