Diffraction microstrain in nanocrystalline solids under load - heterogeneous medium approach

This is an account of the computation of X-ray microstrain in a polycrystal with anisotropic elasticity under uniaxial external load. The results have been published in the article "Microstrain in nanocrystalline solids under load by virtual diffraction", at Europhysics Letters 89, 66002 (2010). The present information was submitted to Europhysics Letters as part of the manuscript package, and was available to the reviewers who recommended the paper for publication.Comment: Supporting online material for J. Markmann, D. Bachurin, L.-H. Shao, P. Gumbsch, J. Weissm\"uller, Microstrain in nanocrystalline solids under load by virtual diffraction, Europhys. Lett. 89, 66002 (2010

Typology of Legal Regulation of Value-Added Taxation in the BRICS States

Value-added taxation (VAT) is an essential component of the financial system of any modern state, which determines the attention of the legislator to the development of its legal regulation, as well as the subject of this article. The processes of transformation of VAT legal regulation systems that are observed in the BRICS countries (the People’s Republic of China, the Republic of India, the Federal Republic of Brazil, the Russian Federation, and the Republic of South Africa) demonstrate the greatest activity in this area of legal relations. The task of studying such changes, which makes it possible to identify common features and individual features of various types of legal regulation of value-added taxation, is solved on the basis of an integrated assessment of the characteristics of the tax redistribution of value added. Based on the results of their research, the types of legal regulation of VAT in the BRICS countries are identified and the place that the Russian model of legal regulation of VAT occupies in this classification is determined

Legal and Regulatory Reform of Value-Added Taxation in the People’s Republic of China and the Republic of India: Trends and Characteristics

Value-added taxation is a multidimensional theoretical, fiscal and legal structure. It also serves as a tool for the practical transformation of political, legal and socio-economic relations. The objective of the research is to study new concepts of value-added taxation formed in the two largest BRICS economies (the People’s Republic of China and the Republic of India). The assumption is that not only “European” model of the legal regulation of VAT can be successful, but alternatively “Chinese” and “Indian models.” The author examines and evaluates changes in the legal structure of value added tax in general, and its elements focusing on the current stage of legal regulation of national systems of VAT (GST) in China and India. In addition, the political, legal, social and economic effects of the legal mechanism of VAT (GST) in China and India from 2017 to 2020 are demonstrated

Ab initio study of hydrogen behavior in titanium beryllides

An interest in titanium beryllides as candidate materials for advanced neutron multiplier for the Helium Cooled Pebble Bed breeding blanket of European DEMO fusion reactor is related to their lower tritium retention, lower swelling and higher oxidation resistance in comparison with pure beryllium. The latter was initially suggested as neutron multiplier in the International Thermonuclear Experimental Reactor (ITER) and for the above reasons has a number of limitations compared to beryllides. One of the most important questions is how much weaker tritium, which is formed as a result of the interaction of high-energy neutrons with the pebbles is bound in titanium beryllides in contrast to pure beryllium. Such an interaction awakes formation of helium bubbles and degradation of the material properties. One of the main promising methods for studying the behavior of hydrogen in titanium beryllides is first-principles modeling technique based on density functional theory. The present work is devoted to ab initio study of hydrogen (isotope effects were neglected and hydrogen was considered instead of tritium) behavior in three titanium beryllides (Be2Ti, Be17Ti2, Be12Ti). All of them have different crystal structure and contain a different number of crystallographically non-equivalent interstitial hydrogensites. Both the hydrogen solution energy in defect-free lattice and binding energy with a vacancy are important characteristics in terms of tritium dissolution, retention and release. Static ab initio calculations demonstrate that hydrogen solution energy in all interstitial non-equivalent sites is noticeably lower as compared with pure beryllium suggesting an easier dissolution of hydrogen atoms in titanium beryllides. Computation of binding energy of single hydrogen atom with all non-equivalent monovacancies reveals that hydrogen might be trapped by a vacancy without being inside it. The obtained results sheds light on the understanding of earlier tritium release in different titanium beryllides during thermo-desorption experiments and expand our knowledge of their properties

Effect of impurities on microstructural evolution under irradiation in beryllium

Impurities are known to affect mechanical properties of beryllium, but their effect on development of irradiation induced microstructure is still unknown. In this contribution we are making further attempt to reveal behavior of impurities in neutron irradiated beryllium pebbles by using both analytical transmission electron microscope (TEM) and first principles computer simulations. TEM studies have revealed Al-Fe-Be precipitates, complex multiple phase precipitates, homogeneous segregations of elements to grain boundaries as well as abundant precipitation along dislocations. All precipitates are richly decorated with helium bubbles which are smaller in size than typical bubbles inside grains. Precipitate-free and helium-bubble-free zones were observed along grain boundaries. Using density functional theory approach, we have calculated interaction of typical solutes found in beryllium, namely, Al, Fe, Cr, Mg and Si with vacancies, interstitials and free surfaces which can simulate a surface of helium bubbles. Interesting correlation has been revealed: an impurity which has attractive binding with a vacancy has also positive affinity to free surface. In particular, Al, Mg and Si are strongly bound with vacancies and also attracted by the free surfaces. This result is supported by the EDX measurements, (see Fig. above) which reveal decoration of He bubbles with Al, Si and Mg, while Fe is homogeneously distributed. Those impurities which repulse vacancies are attracted by self-interstitials, however, no correlation with the formation volume of respective substitutional atoms was found in this case

Mathematical retroreflectors

Retroreflectors are optical devices that reverse the direction of incident beams of light. Here we present a collection of billiard type retroreflectors consisting of four objects; three of them are asymptotically perfect retroreflectors, and the fourth one is a retroreflector which is very close to perfect. Three objects of the collection have recently been discovered and published or submitted for publication. The fourth object - notched angle - is a new one; a proof of its retroreflectivity is given.Comment: 32 pages, 19 figure