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

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

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

INTRA-FAMILY DIALOGUES ABOUT PROFESSION: LINGUOAXIOLOGICAL INTERPRETATION

The paper presents the results of linguoaxiological analysis of two intra-family dialogues. Audio recordings of 60-minute duration were made in Ekaterinburg in 2018. Communicative partners: daughter - student of 18 years, mother - teacher of 44 years; daughter - student of 19 years, mother - cake baker of 42 years. The object of the analysis is the speech parties of the participants of the communicative interaction. The research purpose is to give orthologous, linguocommunicative, axiological characteristic of dialogues, to identify linguocultural type of personality according to live speech. During the orthological analysis of speech parties of daughters the tendency to use slang terms and expressional lexicon is found, unintentional violation of the codified language norms is recorded. In remarks of mother - cake baker certain features of the urban Urals vernacular are traced, which do not violate the general literary aspect of speech. Both mothers are particular in correctness of their daughters' speech and, taking the position of a communicative leader, regulate the content and phatic components of family communication. The article summarizes the features of intra-family cooperative communication: frankness, mutual orientation, the right to an independent point of view, the dozed use of categorical imperatives and the words of unrest. A special subject of linguoaxiological analysis is the development of a common for both dialogues strategical theme "the path to the profession", included in the mother's biographical time. Interpretation of the basic values nominations, axiological judgments, self-esteem statements allowed to characterize the signs of a linguocultural type of a working mother who chose a profession by vocation: love for the family and love for the profession, conceptual thinking, sense of responsibility, propensity for self-analysis, verification of alternative axiological choice, spiritual but not utilitarian value preferences

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)

АКТУАЛИЗАЦИЯ МЕТОДИКИ РАСЧЕТА ФАКТИЧЕСКОГО ПОКАЗАТЕЛЯ НАДЕЖНОСТИ ВЫЛЕТОВ ГРАЖДАНСКИХ ВОЗДУШНЫХ СУДОВ

Dispatch reliability – is one of the key criteria of aircraft technical operation process efficiency which reflects economic efficiency of airline activity. The higher the operational reliability, the better the level of aircraft operation in airline, the higher maintenance quality and safety policy is more effective. Due to the lack of unified procedure of dispatch reliability control both for aircraft manufacturers and Russian Federation aircraft operators and based on international experience it was concluded that there is a need for dispatch reliability specification by introducing a number of parameters, definitions and development, thereby the unified updated methodic of calculation. In this work six basic and three auxiliary parameters are introduced, the following terms and definitions are established: dispatch reliability, operational reliability, ground operational interruptions, operational interruptions, in-flight  interruptions. A unified actualized methodic of dispatch reliability and operational reliability calculation is developed, which is reasonable and more accurate. Since the aircraft dispatch reliability includes the notion of Regularity and Punctuality, definitions and criteria calculation are given.  The detailed example of criteria calculation is shown: dispatch reliability, dispatch regularity, flight punctuality, operational reliability, flight delays for a hundred landings, aircraft changes for a hundred landings, flight cancellations for a hundred landings.Надежность вылетов (далее – регулярность вылетов) – это один из ключевых критериев эффективности процесса технической эксплуатации воздушных судов, отражающий экономическую эффективность функционирования авиакомпании. Чем выше показатель эксплуатационной надежности выполнения рейсов, тем лучше авиакомпания справляется с эксплуатацией воздушных судов, тем выше качество обслуживания самолетов и эффективнее политика безопасности. В связи с отсутствием единого порядка учета регулярности вылетов воздушных судов как у предприятий – изготовителей воздушных судов, так и у эксплуатирующих воздушные суда авиакомпаний Российской Федерации и основании международного опыта, в работе сделан вывод о необходимости детализации расчета регулярности вылетов путем введения ряда параметров, определений и разработки тем самым единой актуализированной методики расчета. В данной работе введены шесть основных и три вспомогательных параметра, приняты следующие термины и определения: регулярность вылетов; эксплуатационная надежность; наземные сбои в эксплуатации; эксплуатационные прерывания; сбои, произошедшие в полете.  Разработана актуализированная методика расчета регулярности вылетов и эксплуатационной надежности выполнения рейсов, которая является разумной и имеет более высокую точность. Поскольку регулярность вылетов воздушных судов включает понятие регулярности отправлений ВС (Regularity) и пунктуальности выполнения рейсов (Punctuality), даны определения и представлен расчет показателей для данных понятий. Детально показан пример расчета показателей: регулярности вылетов, регулярности отправлений, пунктуальности выполнений рейсов, эксплуатационной надежности выполнения рейсов,  задержки рейсов на сто посадок, замены воздушных судов на сто посадок, отмены рейсов на сто посадок