Christian Population of Majar City and Its Neighborhood: Evidence from Archaeological and Written Sources

Introduction. The article deals with the issue of Christian communities of different denominations to have resided in the city of Majar, the latter localized around Majar hillfort on the Kuma riverside. Christian cult objects have been discovered in the commercial and crafts quarter of the hillfort. Archaeological and written sources make it possible to identify certain groups of Christians — Orthodox, Catholic, and Gregorian (Armenian) ones — within the city’s population. Goals. The study aims to summarize data on Christians in Majar. Nowadays, there is archaeological evidence confirming Majar had been also inhabited by ethnic Russians and Armenians. Materials and methods. The work analyzes the First Sophia Chronicle, sources on Latin missionary activity in the Golden Horde published by Ph. Bruun, A. Malyshev, and R. Hautala, a 1774 map of the Caucasus compiled by Georg Treitel, and archaeological materials. The study employs a number of research methods, such as the historical/systemic, historical/comparative, and cartographic ones. Results. The year 1245 had witnessed earliest contacts between the papacy and the Mongol Empire. In 1260, relations between the Golden Horde and the Byzantine Empire were set up. And in 1267, Metropolitan Kirill II of Kiev received a jarlig from Khan Mengu-Timur. Rulers of the Golden Horde were seeking to achieve various domestic and foreign policy goals through the agenda of religious tolerance. Franciscan missions, parishes of the Alan Metropolitanate, Diocese of Sarai, and the Armenian Church were functioning across the early 14th-century North Caucasus. Some 16th–18th century written sources attest to the presence of a Christian temple within the hillfort of Majar. Materials published by Ph. Bruun, A. Malyshev, and R. Hautala provide evidence Majar and its neighborhood used to host several Franciscan missions throughout the 14th century. Christian cult objects (encolpion cross, copper icon) discovered in the territory of Majar’s trade and crafts quarter testify to that Orthodox Christians had also lived there and had a temple of their own. The Armenian cross-stone (khachkar) which had been part of a church and found at the ancient site suggests there may have been an Armenian community and an Armenian temple too. Conclusions. The available evidence of the presence of different Christian denominations in Majar insufficiently reveals their role in the city’s life. And it gets urgent to localize the Christian quarter at the ancient site of Majar. So, the search for archival materials and archaeological explorations of the site should be continued

Time dependent decomposition of ammonia borane for the controlled production of 2D hexagonal boron nitride.

Ammonia borane (AB) is among the most promising precursors for the large-scale synthesis of hexagonal boron nitride (h-BN) by chemical vapour deposition (CVD). Its non-toxic and non-flammable properties make AB particularly attractive for industry. AB decomposition under CVD conditions, however, is complex and hence has hindered tailored h-BN production and its exploitation. To overcome this challenge, we report in-depth decomposition studies of AB under industrially safe growth conditions. In situ mass spectrometry revealed a time and temperature-dependent release of a plethora of NxBy-containing species and, as a result, significant changes of the N:B ratio during h-BN synthesis. Such fluctuations strongly influence the formation and morphology of 2D h-BN. By means of in situ gas monitoring and regulating the precursor temperature over time we achieve uniform release of volatile chemical species over many hours for the first time, paving the way towards the controlled, industrially viable production of h-BN

A Graphene Surface Force Balance

We report a method for transferring graphene, grown by chemical vapor deposition, which produces ultraflat graphene surfaces (root-mean-square roughness of 0.19 nm) free from polymer residues over macroscopic areas (>1 cm2). The critical step in preparing such surfaces involves the use of an intermediate mica template, which itself is atomically smooth. We demonstrate the compatibility of these model surfaces with the surface force balance, opening up the possibility of measuring normal and lateral forces, including friction and adhesion, between two graphene sheets either in contact or across a liquid medium. The conductivity of the graphene surfaces allows forces to be measured while controlling the surface potential. This new apparatus, the graphene surface force balance, is expected to be of importance to the future understanding of graphene in applications from lubrication to electrochemical energy storage systems

Tunable Anion-Selective Transport through Monolayer Graphene and Hexagonal Boron Nitride.

Membranes that selectively filter for both anions and cations are central to technological applications from clean energy generation to desalination devices. 2D materials have immense potential as these ion-selective membranes due to their thinness, mechanical strength, and tunable surface chemistry; however, currently, only cation-selective membranes have been reported. Here we demonstrate the controllable cation and anion selectivity of both monolayer graphene and hexagonal boron nitride. In particular, we measure the ionic current through membranes grown by chemical vapor deposition containing well-known defects inherent to scalably produced and wet-transferred 2D materials. We observe a striking change from cation selectivity with monovalent ions to anion selectivity by controlling the concentration of multivalent ions and inducing charge inversion on the 2D membrane. Furthermore, we find good agreement between our experimental data and theoretical predictions from the Goldman-Hodgkin-Katz equation and use this model to extract selectivity ratios. These tunable selective membranes conduct up to 500 anions for each cation and thus show potential for osmotic power generation

Oxidising and carburising catalyst conditioning for the controlled growth and transfer of large crystal monolayer hexagonal boron nitride

Funder: H2020 Marie Skłodowska-Curie Actions; doi: https://doi.org/10.13039/100010665Abstract: Hexagonal boron nitride (h-BN) is well-established as a requisite support, encapsulant and barrier for 2D material technologies, but also recently as an active material for applications ranging from hyperbolic metasurfaces to room temperature single-photon sources. Cost-effective, scalable and high quality growth techniques for h-BN layers are critically required. We utilise widely-available iron foils for the catalytic chemical vapour deposition (CVD) of h-BN and report on the significant role of bulk dissolved species in h-BN CVD, and specifically, the balance between dissolved oxygen and carbon. A simple pre-growth conditioning step of the iron foils enables us to tailor an error-tolerant scalable CVD process to give exceptionally large h-BN monolayer domains. We also develop a facile method for the improved transfer of as-grown h-BN away from the iron surface by means of the controlled humidity oxidation and subsequent rapid etching of a thin interfacial iron oxide; thus, avoiding the impurities from the bulk of the foil. We demonstrate wafer-scale (2″) production and utilise this h-BN as a protective layer for graphene towards integrated (opto-)electronic device fabrication

Tailoring the synthesis of graphene and other 2D materials towards applications

This thesis focuses on using Chemical Vapour Deposition (CVD) technique to produce various classes of flat 2D materials and also their three-dimensional architectures. Graphene, hexagonal boron nitride (hBN) and tungsten disulfide (WS2) are the main examples presented in the study: a conductor, an insulator and a semiconductor respectively. Such materials are elementary "building blocks" in a variety of applications. Many novel advances to CVD synthesis of 2D materials are identified, developed and discussed in this thesis

Tailoring the synthesis of graphene and other 2D materials towards applications

This thesis focuses on using Chemical Vapour Deposition (CVD) technique to produce various classes of flat 2D materials and also their three-dimensional architectures. Graphene, hexagonal boron nitride (hBN) and tungsten disulfide (WS2) are the main examples presented in the study: a conductor, an insulator and a semiconductor respectively. Such materials are elementary "building blocks" in a variety of applications. Many novel advances to CVD synthesis of 2D materials are identified, developed and discussed in this thesis

Relationship Between Facial Areas With the Greatest Increase in Non-local Contrast and Gaze Fixations in Recognizing Emotional Expressions

The aim of our study was to analyze gaze fixations in recognizing facial emotional expressions in comparison with o the spatial distribution of the areas with the greatest increase in the total (nonlocal) luminance contrast. It is hypothesized that the most informative areas of the image that getting more of the observer’s attention are the areas with the greatest increase in nonlocal contrast. The study involved 100 university students aged 19-21 with normal vision. 490 full-face photo images were used as stimuli. The images displayed faces of 6 basic emotions (Ekman’s Big Six) as well as neutral (emotionless) expressions. Observer’s eye movements were recorded while they were the recognizing expressions of the shown faces. Then, using a developed software, the areas with the highest (max), lowest (min), and intermediate (med) increases in the total contrast in comparison with the surroundings were identified in the stimulus images at different spatial frequencies. Comparative analysis of the gaze maps with the maps of the areas with min, med, and max increases in the total contrast showed that the gaze fixations in facial emotion classification tasks significantly coincide with the areas characterized by the greatest increase in nonlocal contrast. Obtained results indicate that facial image areas with the greatest increase in the total contrast, which preattentively detected by second-order visual mechanisms, can be the prime targets of the attention