Method to determine defect positions below a metal surface by STM

The oscillatory voltage dependence of the conductance of a quantum point contact in the presence of a single point-like defect has been analyzed theoretically. Such signals are detectable and may be exploited to obtain information on defect positions below a metal surface. Both tunnel junctions and ballistic contacts of adiabatic shape have been considered. The effect of quantum interference has been taking into account between the principal wave that is directly transmitted through the contact and the partial wave that is scattered by the contact and the defect. This effect leads to oscillations of the conductance as a function of applied voltage. We obtain the dependence of the period and amplitude of the conductance oscillations on the position of the defect inside the metal.Comment: 16 pages, 7 figure

Conductance of a STM contact on the surface of a thin film

The conductance of a contact, having a radius smaller than the Fermi wave length, on the surface of a thin metal film is investigated theoretically. It is shown that quantization of the electron energy spectrum in the film leads to a step-like dependence of differential conductance G(V) as a function of applied bias eV. The distance between neighboring steps in eV equals the energy level spacing due to size quantization. We demonstrate that a study of G(V) for both signs of the voltage maps the spectrum of energy levels above and below Fermi surface in scanning tunneling experiments.Comment: 15 pages, 5 figure

Signature of Fermi surface anisotropy in point contact conductance in the presence of defects

In a previous paper (Avotina et al.,Phys. Rev. B Vol.71, 115430 (2005)) we have shown that in principle it is possible to image the defect positions below a metal surface by means of a scanning tunnelling microscope. The principle relies on the interference of electron waves scattered on the defects, which give rise to small but measurable conductance fluctuations. Whereas in that work the band structure was assumed to be free-electron like, here we investigate the effects of Fermi surface anisotropy. We demonstrate that the amplitude and period of the conductance oscillations are determined by the local geometry of the Fermi surface. The signal results from those points for which the electron velocity is directed along the vector connecting the point contact to the defect. For a general Fermi surface geometry the position of the maximum amplitude of the conductance oscillations is not found for the tip directly above the defect. We have determined optimal conditions for determination of defect positions in metals with closed and open Fermi surfaces.Comment: 23 pages, 8 figure

Temperature-dependent quantum electron transport in 2D point contact

We consider a transmission of electrons through a two-dimensional ballistic point contact in the low-conductance regime below the 0.7-anomaly. The scattering of electrons by Friedel oscillations of charge density results in a contribution to the conductance proportional to the temperature. The sign of this linear term depends on the range of the electron-electron interaction and appears to be negative for the relevant experimental parameters.Comment: 10 pages, 5 figure

Интегрированная логистическая поддержка управления процессами поддержания летной годности воздушных судов

The article presents the results of research on the analysis of logistic support processes of maintaining of the aircraft (AC) airworthiness (AW), the solution of problems of scientific and methodological support: analysis of logistics support and formation of an integrated logistics support (ILS).В статье приведены результаты исследований по анализу логистической поддержки процессов поддержания летной годности (ПЛГ) воздушных судов (ВС), решению задач научно-методического обеспечения: анализа логистической поддержки и формирования системы интегрированной логистической поддержки (ИЛП)

К 100-ЛЕТНЕМУ ЮБИЛЕЮ ПЕРВОЙ В МИРЕ КАФЕДРЫ РЕНТГЕНОЛОГИИ

The article reflects the stages of development of the first in the world department of radiology throughout the century. During the existence of the department, it was headed by eminent scientists. Under their leadership, the department staff made an invaluable contribution not only to the development of radiology as a science, but also to the development of teaching this specialty in the USSR. The traditions of innovation and teaching excellence laid down by the founders of the department are preserved and developed at the present stage.В статье отражены этапы развития первой в мире кафедры рентгенологии на протяжении века. За время существования кафедры ею руководили выдающиеся ученые. Под их руководством сотрудники кафедры внесли неоценимый вклад не только в развитие рентгенологии как науки, но и в становление преподавания этой специальности в СССР. Традиции новаторства и мастерства преподавания, заложенные основоположниками кафедры, сохраняются и развиваются на современном этапе

Secreted hydrolases from streptomycin-resistant strains of Bacillus intermedius

Alkaline phosphatase and serine proteinase have been isolated from streptomycin-resistant strains of Bacillus intermedius using ion-exchange, affinity and FPLC chromatography. Substrate blotting analysis and electrophoresis revealed two phosphatase forms with molecular weight of 40 and 50 kDa. The pH and temperature optima of phosphatase were at pH 9.5 and 50°C. The enzyme showed a broad substrate specificity. It was suggested that the two forms of phosphatase are the products of processing, in which serine proteinase is the participant. Two proteinase peaks with molecular weights of 29 and 33 kDa were isolated from B. intermedius S7, the first peak having only 5% of the activity of the second peak. The major peak was identical to serine proteinase described earlier. The minor peak was distinct from the major one by the pH-optima. Analysis of inhibitors' effects revealed that the minor peak also corresponded to serine proteinase

Secreted hydrolases from streptomycin-resistant strains of Bacillus intermedius

Alkaline phosphatases and serine proteinases have been isolated from the culture liquid of streptomycin-resistant strains of Bacillus intermedius using ion-exchange and affinity chromatography and FPLC. Substrate blotting and electrophoresis revealed two phosphatase forms with molecular masses of 40 and 50 kD. The enzyme had maximal activity at pH 9.5 and 50°C and could cleave the phosphate moiety from a range of substrates. It is suggested that both forms of the phosphatase are products of processing that involves a serine proteinase. Two proteinases, with molecular masses of 29 and 33 kD, were purified to homogeneity from the culture liquid of A. intermedius S7. The protein from the major peak was identical in its properties to an earlier described serine proteinase. The minor peak was 5% of the major one. These enzymes had different pH optima. Inhibitor analysis indicated that the minor peak is also a serine proteinase

The Value System of Today’s Students: From Family Well-Being to Self-Realisation

The article was submitted on 24.10.2022.Социальные изменения новейшего времени оказывают влияние на ценностные предпочтения молодых людей. В статье представлены результаты комплексного лингвокогнитивного и социопсихологического экспериментального исследования, проведенного коллективом лингвистов Уральского федерального университета, целью которого является определение ценностных координат студенческой молодежи. На первом этапе на основе оригинальной процедуры выявления ключевых концептов русского менталитета был сконструирован список из 59 общенациональных базовых ценностей, который был предъявлен 633 студентам-первокурсникам Уральского федерального университета. В результате содержательной интерпретации материала установлено, что поколение молодых людей, родившихся в постсоветской России, становится носителем новых ценностей. Отсутствие интереса к политическим институтам, формирование Я-менталитета и микросолидарности в рамках узкого круга семьи и близких людей – эти ценностные предпочтения очертили ядро из восьми базовых концептов, имеющих абстрактный характер, которое потребовало своей конкретизации. На следующем этапе исследования анкета, включающая развернутую смысловую структуру ядерных концептов, была предъявлена студентам-первокурсникам (650 респондентов) с целью определения ядерных и периферийных концептуальных смыслов в языковом сознании студенческой молодежи. Кластерный анализ материала показал, что верхнюю ступень дендрограммы занимает концепт благополучие близких людей. В работе показана динамика в осмыслении аксиологемы благополучие. По данным исторических и церковнославянских лексикографических источников, языковая единица благополучие уже с XI в. имплицитно совмещает в себе ценности материального, физического и идеального, духовного, что подтверждают словари ХХ в. Студенты эксплицируют свой выбор в пользу духовной стороны благополучия. Показано, что на верхних ступенях дендрограммы в комплексе представлены четыре базовых ценности: концепты семья, самореализация, вера и счастье. Подтвердился статус ценностного смысла самореализация для молодых людей студенческого уровня, который напрямую связан с семьей и ее благополучием. Из набора когнитивных признаков концепта вера студенты предпочли ценностный смысл уверенность в своих силах, что позволяет сделать вывод, что они склонны чувствовать веру в собственные способности и возможности, обладают позитивной самооценкой, испытывают доверие к себе. Ценности, включающие материальное благополучие, находятся на периферии языкового сознания молодежи, что не укладывается в общепринятую картину наблюдаемого прагматического отношения молодежи к современной действительности. Высказано предположение, что сложившаяся картина иерархии ценностных признаков носит декларативный характер: молодые люди, недавно окончившие школу, имеют твердые представления о необходимых нормах социального поведения, сложившихся в российском обществе, поэтому ставят духовные ценности выше материальных.The social changes of the modern era influence young people’s value preferences. This paper presents the results of a comprehensive linguo-cognitive and sociopsychological experimental study by a team of linguists from Ural Federal University, which aims to determine students’ value coordinates. In the first stage, based on the original procedure for revealing the key concepts of Russian mentality, the authors constructed a list of 59 nationwide core values and presented them to 633 first-year students at Ural Federal University. As a result of further content interpretation of the material, the researchers discovered that the generation of young people born in post-Soviet Russia is becoming a bearer of new values. The lack of interest in political institutions, the formation of self-mentalism, and micro-solidarity within the narrow circle of family and close people – these value preferences outlined a core of eight basic concepts, having an abstract nature, which required concretisation. At the next stage, the authors presented a questionnaire including a detailed semantic structure of nuclear concepts to first-year students (650 respondents) to determine the nuclear and peripheral conceptual meanings in students’ language consciousness. The cluster analysis of the material demonstrated that the top level of the dendrogram is occupied by the concept of the well-being of loved ones. The paper reveals the complex semantics of the “well-being” concept and shows the axiological dynamics in comprehending the axiologeme. According to historical and Church Slavonic lexicographic sources, the “well-being” linguistic unit has implicitly combined the values of the material, physical, ideal, and spiritual since the eleventh century. Twentieth-century dictionaries confirm the presence of two zones in the semantics of the concept, i. e. the inseparable unity of the spiritual and the material. Students express their choice in favour of the spiritual side of well-being. The article shows that on the upper levels of the dendrogram, there are four basic values in a complex: the concepts of family, self-realisation, faith, and happiness. Also, the authors confirm the status of the self-realisation value sense for young people at the student level, which is directly related to the family and its well-being. As for the cognitive attributes of the faith concept, the students preferred the selfrealisation value sense, which suggests that the respondents have faith in their abilities and capabilities, positive self-esteem, and trust in themselves. Values related to material well-being are on the periphery of the linguistic consciousness of Ural youth, which does not fit in the general picture of the observed pragmatic attitude of young people to modern reality. It has been suggested that the current picture of the hierarchy of value attributes is declarative: young people who have recently left school have a clear idea of the necessary norms of social behaviour established in Russian society, and they put spiritual values over material ones