149 research outputs found

    Rotary-screw-engines

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    Diagnosability of Fuzzy Discrete Event Systems

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    In order to more effectively cope with the real-world problems of vagueness, {\it fuzzy discrete event systems} (FDESs) were proposed recently, and the supervisory control theory of FDESs was developed. In view of the importance of failure diagnosis, in this paper, we present an approach of the failure diagnosis in the framework of FDESs. More specifically: (1) We formalize the definition of diagnosability for FDESs, in which the observable set and failure set of events are {\it fuzzy}, that is, each event has certain degree to be observable and unobservable, and, also, each event may possess different possibility of failure occurring. (2) Through the construction of observability-based diagnosers of FDESs, we investigate its some basic properties. In particular, we present a necessary and sufficient condition for diagnosability of FDESs. (3) Some examples serving to illuminate the applications of the diagnosability of FDESs are described. To conclude, some related issues are raised for further consideration.Comment: 14 pages; revisions have been mad

    Quantum phase transitions and thermodynamic properties in highly anisotropic magnets

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    The systems exhibiting quantum phase transitions (QPT) are investigated within the Ising model in the transverse field and Heisenberg model with easy-plane single-site anisotropy. Near QPT a correspondence between parameters of these models and of quantum phi^4 model is established. A scaling analysis is performed for the ground-state properties. The influence of the external longitudinal magnetic field on the ground-state properties is investigated, and the corresponding magnetic susceptibility is calculated. Finite-temperature properties are considered with the use of the scaling analysis for the effective classical model proposed by Sachdev. Analytical results for the ordering temperature and temperature dependences of the magnetization and energy gap are obtained in the case of a small ground-state moment. The forms of dependences of observable quantities on the bare splitting (or magnetic field) and renormalized splitting turn out to be different. A comparison with numerical calculations and experimental data on systems demonstrating magnetic and structural transitions (e.g., into singlet state) is performed.Comment: 46 pages, RevTeX, 6 figure

    Характеризация наночастиц кристаллического кремния, легированного железом, и их модификация цитрат-анионами для использования in vivo

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    Objectives. This paper presents data on the development and study of the structural properties of iron-doped crystalline silicon (nc-Si/SiOx/Fe) nanoparticles obtained using the plasma-chemical method for application in magnetic resonance imaging diagnostics and treatment of oncological diseases. This work aimed to use a variety of analytical methods to study the structural properties of nc-Si/SiOx/Fe and their colloidal stabilization with citrate anions for in vivo applications.Methods. Silicon nanoparticles obtained via the plasma-chemical synthesis method were characterized by laser spark emission spectroscopy, atomic emission spectroscopy, Fouriertransform infrared spectroscopy, and X-ray photoelectron spectroscopy. The hydrodynamic diameter of the nanoparticles was estimated using dynamic light scattering. The toxicity of the nanoparticles was investigated using a colorimetric MTT test for the cell metabolic activity. Elemental iron with different Fe/Si atomic ratios was added to the feedstock during loading.Results. The particles were shown to have a large silicon core covered by a relatively thin layer of intermediate oxides (interface) and an amorphous oxide shell, which is silicon oxide with different oxidation states SiOx (0 ≤ x ≤ 2). The samples had an iron content of 0.8–1.8 at %. Colloidal solutions of the nanoparticles stabilized by citrate anions were obtained and characterized. According to the analysis of the cytotoxicity of the modified nanosilicon particles using monoclonal K562 human erythroleukemia cells, no toxicity was found for cells in culture at particle concentrations of up to 5 µg/mL.Conclusions. Since the obtained modified particles are nontoxic, they can be used in in vivo theranostic applications.Цели. В работе приводятся данные по разработке и изучению структурных свойств полученных плазмохимическим методом наночастиц кремния nc-Si/SiOx/Fe, легированных железом. Цель работы – исследование свойств наночастиц кремния, легированных железом, комплексом аналитических методов и их стабилизация цитрат-анионами для применения в диагностике методом магнитно-резонансной томографии и лечении онкологических заболеваний.Методы. Наночастицы кремния, полученные плазмохимическим методом синтеза, были охарактеризованы лазерно-искровым эмиссионным методом, методом атомной эмиссионной спектроскопии, Фурье-ИК-спектроскопией, рентгеновской фотоэлектронной спектроскопией. Гидродинамический диаметр наночастиц оценивали методом динамического светорассеяния. Исследование токсичности наночастиц проводили с помощью колориметрического МТТ теста на метаболическую активность клеток. В исходное сырье при загрузке добавляли элементарное железо с разным атомным соотношением Fe/Si.Результаты. Было показано, что частица имеет кремниевое ядро с аморфной оксидной оболочкой, представляющей собой оксиды кремния с разной степенью окисления SiO x (0 ≤ x ≤ 2). Содержание железа в образцах составило от 0.8 до 1.8 ат. %. Были получены и охарактеризованы коллоидные растворы наночастиц, стабилизированные цитрат-анионами. Анализ цитотоксичности модифицированных частиц нанокремния с использованием моноклонизированных клеток эритролейкоза человека К562 показал отсутствие токсичности для клеток в культуре при концентрации частиц до 5 мкг/мл.Выводы. Полученные модифицированные частицы не обладают токсичностью, поэтому их можно рекомендовать для использования в in vivo приложениях для тераностик

    On the methodology for assessing the quality of telemedicine services in the doctor-doctor system

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    The objective was to develop a system of indicators of telemedicine services in the "doctor – doctor" system in order to improve the quality of the organization of remote interaction between medical organizations in providing medical care using telemedical technologies.Цель работы – разработать систему показателей телемедицинских услуг в системе «врач – врач» с целью повышения качества организации дистанционного взаимодействия между медицинскими организациями при оказании медицинской помощи с применением телемедицинских технологий

    Review on computational methods for Lyapunov functions

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    Lyapunov functions are an essential tool in the stability analysis of dynamical systems, both in theory and applications. They provide sufficient conditions for the stability of equilibria or more general invariant sets, as well as for their basin of attraction. The necessity, i.e. the existence of Lyapunov functions, has been studied in converse theorems, however, they do not provide a general method to compute them. Because of their importance in stability analysis, numerous computational construction methods have been developed within the Engineering, Informatics, and Mathematics community. They cover different types of systems such as ordinary differential equations, switched systems, non-smooth systems, discrete-time systems etc., and employ di_erent methods such as series expansion, linear programming, linear matrix inequalities, collocation methods, algebraic methods, set-theoretic methods, and many others. This review brings these different methods together. First, the different types of systems, where Lyapunov functions are used, are briefly discussed. In the main part, the computational methods are presented, ordered by the type of method used to construct a Lyapunov function

    Fast Control Systems: Nonlinear Approach

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    International audienceThis chapter treats the problem of fast control design for nonlinear systems. First, we discusses the question: which nonlinear system can be called fast? Next, we develop some tools for analysis and design of such control systems. The method generalized homogeneity is mainly utilized for these purposes. Finally, we survey possible research directions of the fast control systems

    Sea ice circulation in the Laptev Sea and ice export to the Arctic Ocean: Sea ice circulation in the Laptev Sea and ice export to the Arctic Ocean: Results from satellite remote sensing and numerical modeling

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    Sea ice circulation in the Laptev Sea and ice exchange with the Arctic Ocean have been studied based on remote sensing data and numerical modeling. Ice drift patterns for short‐ and long‐term periods were retrieved from successive Okean radar images and Special Sensor Microwave/Imager data for the winters 1987/1988 and 1994/1995. Seasonal and interannual variabilities of ice drift in the Laptev Sea and ice exchange with the Arctic Ocean during the period from 1979 to 1995 were studied with a large‐scale dynamic‐thermodynamic sea ice model. During an “average year,” sea ice was exported from the Laptev Sea through its northern and eastern boundaries, with maximum and minimum export occurring in February and August, respectively. The winter ice outflow from the Laptev Sea varied between 251,000 km2 (1984/1985) and 732,000 km2 (1988/1989) with the mean value of 483,000 km2. Sea ice was exported into the East Siberian Sea mostly in summers with the mean value of 69,000 km2. Out of the 17 investigated summers, 12 were characterized by sea ice import from the Arctic Ocean into the Laptev Sea through its northern boundary. Magnitude and direction of ice export from the Laptev Sea corresponded with the large‐scale Arctic Ocean drift patterns during periods of prevailing cyclonic or anticyclonic circulation. Based on a semiempirical method that has been validated with the large‐scale model and satellite data, ice exchange between the Laptev Sea and the Arctic Ocean during the period from 1936 to 1995 has been estimated as 309,000km2 with strong interannual variability and no significant trend apparent
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