167 research outputs found
Metastable phases and "metastable" phase diagrams
The work discusses specifics of phase transitions for metastable states of
substances. The objects of condensed media physics are primarily equilibrium
states of substances with metastable phases viewed as an exception, while the
overwhelming majority of organic substances investigated in chemistry are
metastable. It turns out that at normal pressure many of simple molecular
compounds based on light elements (these include: most hydrocarbons; nitrogen
oxides, hydrates, and carbides; carbon oxide (CO); alcohols, glycerin etc) are
metastable substances too, i.e. they do not match the Gibbs' free energy
minimum for a given chemical composition. At moderate temperatures and
pressures, the phase transitions for given metastable phases throughout the
entire experimentally accessible time range are reversible with the equilibrium
thermodynamics laws obeyed. At sufficiently high pressures (1-10 GPa), most of
molecular phases irreversibly transform to more energy efficient polymerized
phases, both stable and metastable. These transformations are not consistent
with the equality of the Gibbs' free energies between the phases before and
after the transition, i.e. they are not phase transitions in "classical"
meaning. The resulting polymeric phases at normal pressure can exist at
temperatures above the melting one for the initial metastable molecular phase.
Striking examples of such polymers are polyethylene and a polymerized
modification of CO. Many of energy-intermediate polymeric phases can apparently
be synthesized by the "classical" chemistry techniques at normal pressure.Comment: 5 pages, 4 figure
Використання методів статистичного аналізу при обробці даних опитування населення
The subject of the study is the processes of information support of organizational projects. The aim of the work is to create an integrated web service for information support of event-manager in the projects of organization of sports competitions. The following tasks are solved in the article: analysis of means of information support of organizational projects, systematization of event-manager functions and means for their fulfillment, development of a web-resource for providing information support of the project of organization of sports competitions. The following methods are used: project management, communication management, queuing theory, integration of information systems, object-oriented programming. The results obtained: An analysis of the means of information support of organizational projects is carried out. It is concluded that the integration of web applications, mapping services and integration tools with social networks is necessary for effective management of organizational projects. Features and software of event-manager of projects of the organization of sports competitions which are systematized according to the main stages of the life cycle were studied. A diagram of use cases has been developed, which is the initial conceptual presentation of the information support system. A web-based user interface has been designed to create and edit online contest routes using a mapping service. The opportunity to integrate the event into the social network Facebook with editing posts was realized. The application of queuing theory methods is justified for managing the organizational risks of the project. Conclusions: Integration of modern technologies provides informational support to the event manager of the project of organization of sports competitions, which provides convenience and shortening of terms of performance of its functions. In addition, the developed web resource allows different types of project stakeholders to participate in polls, register for competitions, view reports from previous events and get directions for competitions directly on the site.Предметом дослідження в статті є процеси інформаційного забезпечення організаційних проектів. Метою роботи є створення інтегрованого веб-сервісу для інформаційної підтримки event-менеджера в проектах організації спортивних змагань. В статті вирішуються наступні завдання: аналіз засобів інформаційного забезпечення організаційних проектів, систематизація функцій event-менеджера та засобів для їх виконання, розробка веб-ресурсу для забезпечення інформаційної підтримки проекту організації спортивних змагань. Застоствуються методи: проектного менеджменту, управління комунікаціями, теорії масового обслуговування, інтеграції інформаційних систем, об’єктно-орієнтованого програмування. Отримано результати: Проведено аналіз засобів інформаційного забезпечення організаційних проектів. Зроблено висновок про необхідність інтеграції веб-додатків, картографічних сервісів та засобів інтеграції з соцмережами для ефективного управління організаційними проектами. Розглянуто функції та програмні засоби event-менеджера проектів організації спортивних змагань, які систематизовано за основними етапами життєвого циклу. Розроблено діаграму варіантів використання, що є вихідним концептуальним поданням системи інформаційної підтримки. Спроектовано інтерфейс користувача веб-ресурсу з можливістю створення та онлайн-редагування маршрутів змагань за допомогою картографічного сервісу. Реалізована можливість інтеграції заходу у соціальну мережу Фейсбук з редагуванням постів. Для управління організаційними ризиками проекту обґрунтовано застосування методів теорії масового обслуговування. Висновки: Інтеграція сучасних технологій забезпечує інформаційну підтримку event-менеджера проекту організації спортивних змагань, що забезпечує зручність та скорочення термінів виконання його функцій. Крім того розроблений веб-ресурс дозволяє різним типам стейкхолдерів проекту брати участь у опитуваннях, реєструватися на змаганнях, дивитись звіти з попередніх подій та прокладати маршрути для змагань безпосередньо на сайті
К решению классической задачи магнитного влияния воздушных линий электропередачи на протяженные проводящие коммуникации
The paper considers a problem pertaining to magnetic interference of overhead power transmission lines and high-voltage bus bars of electrical installations on extended conducting communications and secondary circuits of relay protection and automation. A simplified task solution has been obtained on the basis of the Carson integral approximation.В статье рассматривается проблема определения магнитного влияния воздушных линий электропередачи и высоковольтных шин электроустановок на протяженные проводящие коммуникации и на вторичные цепи релейной защиты и автоматики. Получено упрощенное решение задачи на основе приближенного вычисления интеграла Карсона
Lasing on the D_2 line of sodium in helium atmosphere due to optical pumping on the D_1 line (up-conversion)
A new method is proposed to produce population inversion on transitions
involving the ground state of atoms. The method is realized experimentally with
sodium atoms. Lasing at the frequency corresponding to the sodium D_2 line is
achieved in the presence of pump radiation resonant to the D_1 line with helium
as a buffer gas.Comment: 4 pages, 4 figures, Late
Thermodynamic aspects of materials' hardness: prediction of novel superhard high-pressure phases
In the present work we have proposed the method that allows one to easily
estimate hardness and bulk modulus of known or hypothetical solid phases from
the data on Gibbs energy of atomization of the elements and corresponding
covalent radii. It has been shown that hardness and bulk moduli of compounds
strongly correlate with their thermodynamic and structural properties. The
proposed method may be used for a large number of compounds with various types
of chemical bonding and structures; moreover, the temperature dependence of
hardness may be calculated, that has been performed for diamond and cubic boron
nitride. The correctness of this approach has been shown for the recently
synthesized superhard diamond-like BC5. It has been predicted that the
hypothetical forms of B2O3, diamond-like boron, BCx and COx, which could be
synthesized at high pressures and temperatures, should have extreme hardness
Baryonic Regge trajectories with analyticity constraints
A model for baryonic Regge trajectories compatible with the threshold
behavior required by unitarity and asymptotic behavior in agreement with
analyticity constraints is given in explicit form. Widths and masses of the
baryonic resonances on the N and trajectories are reproduced. The
MacDowell symmetry is exploited and an application is given.Comment: 12 pages, 6 figure
Inversionless gain in a three-level system driven by a strong field and collisions
Inversionless gain in a three-level system driven by a strong external field
and by collisions with a buffer gas is investigated. The mechanism of
populating of the upper laser level contributed by the collision transfer as
well as by relaxation caused by a buffer gas is discussed in detail. Explicit
formulae for analysis of optimal conditions are derived. The mechanism
developed here for the incoherent pump could be generalized to other systems.Comment: RevTeX, 9 pages, 4 eps figure
Information Continuity: A Temporal Approach to Assessing Metadata and Organizational Quality in an Institutional Repository
This paper was presented at the 8th annual Metadata and Semantics Research Conference held in Karlsruhe, Germany, November 27-29, 2014.Repositories provide a vital infrastructure for an institution to aggregate and disseminate creative output, yet this task is only as successful as the effective organization of its content. The University of Kansas is currently undergoing a systematic review to analyze metadata and content organization in its own repository. This paper argues that for a full assessment to be achieved it is necessary to not view the repository as a fixed item, but as an entity with its own continuity. This temporal approach has a significant impact on establishing resource provenance for metadata policy adjustments, disciplinary migration, and resource extensibility. For any repository it is essential for ensuring long-term viability
Synthesis and antifungal activity of monoterpenoids of the carane series
The antifUngal activity of terpenoids of the carane series was studied; an interaction was found between the structures of these compounds and their antifungal properties. The actions of several terpenoids on the adhesive activity and enzyme systems of the fungus Candida albicans were studied. © 2012 Springer Science+Business Media, Inc
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