Piecewise acceleration of electrons across a periodic solid-state structure irradiated by intense laser pulse

Three-dimensional particle-in-cell simulations show that the periodic solid-state structures irradiated by intense ($\sim 10^{19}$ W/cm${}^2$) laser pulses can generate collimated electron bunches with energies up to 30 MeV (and acceleration gradient of $11.5$ GeV/cm), if the microstructure period is equal to the laser wavelength. A one-dimensional model of piecewise acceleration in the microstructure is proposed and it is in a good agreement with the results of numerical simulations. It shows that the acceleration process for relativistic electrons can be theoretically infinite. In the simulations, the optimal target parameters (the width of the microstructure elements and the microstructure period) are determined. The explored parameters can be used for proof-of-principle experiments demonstrating an ultrahigh gradient acceleration by a number of identical and mutually coherent laser pulses [A. Pukhov et al., Eur. Phys. J. Spec. Top. 223, 1197 (2014)]

Physical mathematical bases of the principle of independence of cavity expansion

For the first steps of cavitation researches the very important general peculiarity of supercavitating flow was found which discovered practical independence of cavity sections expansion in motionless fluid. This peculiarity gave the possibility for practical estimation of the cavities in the most part of applications. The paper presents the system of the simple dependencies for practical calculations of axisymmeric and near to one supecavitation flows with account of its perfection on the base of modern achievements of the theoretic and experimental research which based on the property of independence of the cavity section expansion. Main attention is paid to asymptotic dependencies on the base of Slender Body Theory and heuristic models. The calculations examples of steady and unsteady cavities for motion under gravity, axelration, harmonic oscillation of pressure are given. The problems of ventilated cavities and possible ways of drag reduction for motion with supercavitation are considered.http://deepblue.lib.umich.edu/bitstream/2027.42/84216/1/CAV2009-final169.pd

“Correlation is the Truth of all Existence,” or Interdisciplinarity as a Methodological Principle of Adequate Social Cognition

The article demonstrates that interdisciplinarity is not only a characteristic of the modern stage of scientific knowledge, as it is usually stated. Nevertheless, it is a methodological expression of the ambiguous nature of knowledge about any social subject, which makes us consider it as a requirement for adequate social knowledge. This nature of knowledge about a social subject stems from the fact that every existing thing (including a social one), always, “by nature” in relations with other things, discovers that it is itself (“the truth of its existence”), only through this relationship, only through another thing, only in interaction with it. We can call this the nature of a thing; the way it exists. Moreover, if all the definitions of a thing, all knowledge about a thing that arises specifically, as a result of its various relationships with other things, are essential for its understanding and cannot be ignored when defining a thing. Then an adequate knowledge of such a thing (social things) will always be only its knowledge as the dialectical unity of many definitions. This implies that the external expression of this fact is interdisciplinarity as a methodological principle of adequate knowledge. That is, adequate knowledge of a thing (which is always multifaceted) is possible only through the interaction of the potential of separate, historically developed systems of concepts that correspond to these faces and form separate social disciplines, i.e. only as interdisciplinary knowledge

Protección legal del uso transfronterizo de la propiedad intelectual

The paper analyzes the issues of legal regulation of cross-border use of intellectual property on the example of the Eurasian Economic Union. Among the key problems of cross-border use of intellectual property within the Eurasian Economic Union (EEU) is the need to create a unified system of registration of trademarks and service marks and elimination of double registration of trademarks, establishment of common approaches to the problem of admissibility of “parallel imports” within the EEU, and the creation of an effective patent system. The authors conclude that the development of legal regulation of the use of intellectual property in cross-border relations will follow the path of adoption of normative acts within the framework of regional unions of states, taking into account the specifics of their economic and social development, as well as the way of improvement of national legislation, taking into account the position of states on this issue.El artículo analiza los problemas de regulación legal del uso transfronterizo de la propiedad intelectual en el ejemplo de la Unión Económica Euroasiática. Entre los problemas clave del uso transfronterizo de la propiedad intelectual dentro de la Unión Económica Euroasiática (EEU) está la necesidad de crear un sistema unificado de registro de marcas y marcas de servicio y la eliminación del doble registro de marcas, el establecimiento de enfoques comunes para el problema de admisibilidad de “importaciones paralelas” dentro de la EEU, y la creación de un sistema efectivo de patentes. Los autores concluyen que el desarrollo de la regulación legal del uso de la propiedad intelectual en las relaciones transfronterizas seguirá el camino de la adopción de actos normativos en el marco de las uniones regionales de estados, teniendo en cuenta los detalles de su desarrollo económico y social así como la forma de mejorar la legislación nacional, teniendo en cuenta la posición de los Estados sobre este tema

Schur function expansion in non-Hermitian ensembles and averages of characteristic polynomials

We study $k$-point correlators of characteristic polynomials in non-Hermitian ensembles of random matrices, focusing on the real, complex and quaternion $N \times N$ Ginibre ensembles. Our approach is based on the technique of character expansions, which expresses the correlator as a sum over partitions involving Schur functions. We show how to re-sum the expansions in terms of representations which interchange the roles of $N$ and $k$. We also provide a probabilistic interpretation of the character expansion analogous to the Schur measure, linking the correlators to the distribution of the top row in certain Young diagrams. In more specific examples we evaluate these expressions explicitly in terms of $k \times k$ determinants or Pfaffians. We show that our approach extends to other ensembles, such as truncations of random unitary matrices.Comment: 35 page

High speed motion in water with supercavitation for sub-, trans-, supersonic Mach Numbers

The results of research for supercavitating motion in water at very high speeds comparable with sonic speed ~1500m/s are presented. At such speeds the water is a compressible fluid and the basic compressible hydrodynamics of supercavitating flows together with practical approaches and experimental data are considered. The theory of ballistic projectiles motion is developed with emphasis on the problems of maximal range, lateral motion prediction and problems of minimal declination, hydro-elastic effects, and resonant oscillation frequencies. One main purpose of the article is an attempt to advance the level of understanding of the problem of very high-speed underwater launch by a comprehensive review of previous research on this topic.http://deepblue.lib.umich.edu/bitstream/2027.42/84267/1/CAV2009-final72.pd