Stability of non-linear integrable accelerator

The stability of non-linear Integrable Optics Test Accelerator (IOTA) model was tested. The area of the stable region in transverse coordinates and the maximum attainable tune spread were found as a function of non-linear lens strength. Particle loss as a function of turn number was analyzed to determine whether a dynamic aperture limitation present in the system. The system was also tested with sextupoles included in the machine for chromaticity compensation. A method of evaluation of the beam size in the linear part of the accelerator was proposed.Comment: 10 p

Autoresonant excitation of Bose-Einstein condensates

Controlling the state of a Bose-Einstein condensate driven by a chirped frequency perturbation in a one-dimensional anharmonic trapping potential is discussed. By identifying four characteristic time scales in this chirped-driven problem, three dimensionless parameters $P_{1,2,3}$ are defined describing the driving strength, the anharmonicity of the trapping potential, and the strength of the particles interaction, respectively. As the driving frequency passes the linear resonance in the problem, and depending on the location in the $P_{1,2,3}$ parameter space, the system may exhibit two very different evolutions, i.e. the quantum energy ladder climbing (LC) and the classical autoresonance (AR). These regimes are analysed both in theory and simulations with the emphasis on the effect of the interaction parameter $P_{3}$. In particular, the transition thresholds on the driving parameter $P_{1}$ and their width in $P_{1}$ in both the AR and LC regimes are discussed. Different driving protocols are also illustrated, showing efficient control of excitation and de-excitation of the condensate

Resonant control of solitons

It is shown that the effect of "scattering on resonance" can be used to control envelope solitons in the driven nonlinear Schrödinger equation. The control occurs by the frequency modulated driving with multiple crossing of the resonant frequency of the soliton. Crown Copyright © 2013 Published by Elsevier B.V. All rights reserved

Assignment of the NV0 575 nm zero-phonon line in diamond to a 2E-2A2 transition

The time-averaged emission spectrum of single nitrogen-vacancy defects in diamond gives zero-phonon lines of both the negative charge state at 637 nm (1.945 eV) and the neutral charge state at 575 nm (2.156 eV). This occurs through photo-conversion between the two charge states. Due to strain in the diamond the zero-phonon lines are split and it is found that the splitting and polarization of the two zero-phonon lines are the same. From this observation and consideration of the electronic structure of the nitrogen-vacancy center it is concluded that the excited state of the neutral center has A2 orbital symmetry. The assignment of the 575 nm transition to a 2E - 2A2 transition has not been established previously.Comment: 5 pages, 5 figure

Региональное сотрудничество в области безопасности полетов: международно-правовые вопросы

INTRODUCTION. Based on the analysis of documents and practice of numerous regional international organizations and other present-day forms of regional interstate cooperation in the area of aviation safety and aircraft accident investigation the article examines different international legal issues arising out of such cooperation, including, in particular, the legal nature, powers and membership of these regional international organizations.MATERIALS AND METHODS. The present research has been conducted on the basis of international air law treaties, constituent instruments and decisions of various regional international organizations, the ICAO documents, as well as the works of Russian and foreign international law experts. The methodology of the research is based upon general scientific and special methods, including dialectical method, methods of analysis and synthesis, deduction and induction, comparative legal method.RESEARCH RESULTS. On the basis of his research the author has been able to identify and classify all presentday forms of regional interstate cooperation in the area of aviation safety and aircraft accident investigation, define the legal nature of such forms, examine theoretical and practical international legal issues relating thereto as well as propose recommendations aimed at resolving these issues.DISCUSSION AND CONCLUSIONS. The advantages and the important role of regional cooperation of States in the area of aviation safety oversight and aircraft accident investigation are underlined in the article. However, despite the importance of such cooperation for enhancement of aviation safety, currently its development depends upon the successful resolution of the following problems: – improvement of international legal framework (e.g., international treaties, decisions of international organizations etc.), which governs establishment and functioning of aviation safety oversight and aircraft accident investigation regional international organizations and bodies, in particular, with the aim to expand their powers to perform more complex and important functions in the area of aviation safety oversight and accident investigation for their Member States (e.g., certification of aeronautical products and other civil aviation facilities, conducting full accident investigation etc.); – ensuring more sustainable funding for aviation safety oversight and aircraft accident investigation regional international organizations and bodies; – training of bigger number of aviation professionals performing inspectorial functions in the area of aviation safety oversight as well as aircraft accident and incident investigation functions; – limitation of cases of simultaneous membership of the same States in several aviation safety oversight and aircraft accident investigation regional international organizations. Resolving the problems mentioned above, in particular, on the basis of recommendations proposed in this article, will allow to increase the efficiency and attractiveness of different forms of regional cooperation in the area of aviation safety oversight and aircraft accident investigation for bigger number of States, as well as help to improve regional cooperation of the Russian Federation within the framework of the Eurasian Economic Union and the Commonwealth of Independent States in this area

Релиз PHP 8: возможность обновления библиотечных веб-сайтов

The author explores the possibility to update PHP language up to PHP 8 in the library websites. Such upgrade is determined by the need for recommended safety level for web-resources. As exemplified by St. Petersburg library websites, the role of PHP language is demonstrated: 70% library websites are based on this technology. The content management systems (CMS) and PHP language versions are identified. For the three most popular CMS (CMS WordPress, CMS Joomla!, without CMS), technological recommendations are given on how to transfer to the new PHP versions (as for early 2021). About 28% websites do not use CMS. Their compatibility with PHP new version has to be provided individually. Approx. 28% library websites use CMS Joomla!, and 19% – CMS WordPress. Today, these management systems cannot support PHP 8 in full: WordPress is beta-compatible, while with Joomla! the work has been just in progress. The most recent information for IT specialists interested in library website design is given; releases to follow PHP 8 after November 2020, are described.В статье дана оценка возможности обновления версии языка программирования PHP до новой версии PHP 8 на библиотечных сайтах. Необходимость такого обновления обусловлена рекомендациями по безопасности веб-ресурсов. На примере сайтов библиотек Санкт-Петербурга показана роль рассматриваемого языка программирования: 70% библиотечных сайтов разработаны на основе данной технологии. Определены используемые сайтами системы управления контентом (Content Management System, CMS) и версии языка PHP. Для трёх наиболее популярных вариантов CMS (с применением CMS WordPress, CMS Joomla!, без использования CMS) рассмотрены технические рекомендации по переходу на новую версию PHP по состоянию на начало 2021 г. Около 28% сайтов не используют CMS. Обеспечение их совместимости с новой версией PHP производится индивидуально. В примерно 28% случаев сайты библиотек используют CMS Joomla!, в 19% – CMS WordPress. Эти системы управления сайтом сегодня не готовы к полной поддержке PHP 8: WordPress представляет бета-совместимую версию, Joomla! – только ведёт работы. Приведена наиболее свежая информация для технических специалистов, интересующихся технологиями разработки веб-сайтов для библиотек: описаны выпуски программного обеспечения после релиза PHP 8, т. е. после ноября 2020 г