774 research outputs found

    Photon collimator system for the ILC Positron Source

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    High energy e+e- linear colliders are the next large scale project in particle physics. They need intense sources to achieve the required luminosity. In particular, the positron source must provide about 10E+14 positrons per second. The positron source for the International Linear Collider (ILC) is based on a helical undulator passed by the electron beam to create an intense circularly polarized photon beam. With these photons a longitudinally polarized positron beam is generated; the degree of polarization can be enhanced by collimating the photon beam. However, the high photon beam intensity causes huge thermal load in the collimator material. In this paper the thermal load in the photon collimator is discussed and a flexible design solution is presented.Comment: 22 pages, 19 figures, 8 tables, cross-reference to table 4 fixe

    Placer Minerals of the Russian Arctic Shelf

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    Body composition data from the rat subjects of Cosmos 1129 experiment K-316

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    The effects of 18.5 days of weightlessness on the body composition of young, growing, male laboratory rats were examined. Three groups of 5 rats each were examined. It is indicated that exposure of young, growing, male rats to 18.5 days of weightlessness produces: (1) no effect on the quantity of fat stored by the body; (2) a slight reduction in the quantity of fat free tissue laid down by the body; (3) a small reduction in the fraction of water contained by the fat free body mass; (4) a similar reduction in the fraction of water contained by the fat free skin and fat free carcass; (5) a shift in relative distribution of the total body water from skin to viscera; (6) a diminution in the fraction of extracellular water contained by the fat free body; (7) no effect on the fraction of total skeletal musculature contained by the fat free body, as indicated by body creatine content; (8) a sizeable reduction in the fraction of bone mineral contained by the fat free body, as calculated from body calcium content. The nature of the physiological changes induced by unloading from Earth gravity in the mammalian organism are illustrated

    Design of Pre-Dumping Ring Spin Rotator with a Possibility of Helicity Switching for Polarized Positrons at the ILC

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    The use of polarized beams enhance the possibility of the precision measurements at the International Linear Collider (ILC). In order to preserve the degree of polarization during beam transport spin rotators are included in the current TDR ILC Lattice. In this report some advantages of using a combined spin rotator/spin flipper are discussed. A few possible lattice designs of spin flipper developed at DESY in 2012 are presented.Comment: Talk presented at the International Workshop on Future Linear Colliders (LCWS15), Whistler, Canada, 2-6 November 201

    Multiple-wavelength lasing in one-dimensional bandgap structures: implementation with active n–i–p–i layers

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    We study the optical localized states in a one-dimensional system of strongly coupled defect microcavities for the case when a tight-binding approximation is not valid. Transmission and electromagnetic mode density spectra as well as the distribution of light intensity inside the bandgap material are investigated. We report on the effect of splitting the fundamental coupled-cavity mode into several high-Q submodes to support perfect transmission of light at low group-velocity values. New types of laser microcavities that provide low-threshold lasing at multiple wavelengths and in opposite directions are proposed. Possible implementation of the laser systems with active n–i–p–i layers is discussed

    Features of the calculation of heat losses through the filling of window openings

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    The article is devoted to the calculation of heat losses through the filling of a horse aperture. The scheme of formation of the "cold bridge"through the filling of the window opening was presented. Two window designs were calculated and analysed using numerical simulation. It was calculated to reduce the cost of the project by changing the constructive solution. The article examined various ways to take into account the position of the window opening when calculating heat losses. A formula was proposed for the correct calculation of heat losses through the filling of a window opening. Separately highlighted issues that need to be considered in further research. © Published under licence by IOP Publishing Ltd

    One estimation of the stability defect of sets in an approach game problem

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    A game problem of the approach to a compact target set at a fixed termination time is studied. We investigate the question of estimating the stability defect of a set in the space of game positions, which is weakly invariant with respect to a finite set of unification differential inclusions. © 2015, IFAC Hosting by Elsevier Ltd.Russian Science Foundation, RSF15-11-1001

    Complex therapy of chronic pancreatitis complicated by anxio-depressive disorders in railroad workers

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    The authors have found out negative impact of anxio-depressive disorders on the course of chronic pancreatitis with the development of stable pain syndrome, gastro-intestinal disorders, resistance to the performed pharmacotherapy, and decrease of reaction rate to presented stimul

    Novel electronic states close to Mott transition in low-dimensional and frustrated systems

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    Recent studies demonstrated that there may appear different novel states in correlated systems close to localized-itinerant crossover. Especially favourable conditions for that are met in low-dimensional and in frustrated systems. In this paper I discuss on concrete examples some of such novel states. In particular, for some spinels and triangular systems there appears a "partial Mott transition", in which first some finite clusters (dimers, trimes, tetramers, heptamers) go over to the itinerant regime, and the real bulk Mott transition occurs only later. Also some other specific possibilities in this crossover regime are shortly discussed, such as spin-Peierls-Peierls transition in TiOCl, spontaneous charge disproportionation in some cases, etc.Comment: To be published in Journal of Physics - Condensed Matter, conference serie

    Choosing the optimal type of ventilation units for residential buildings with "warm attic"

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    The article compares two options for the design of ventilation blocks for a residential multi-storey building with a warm attic: from small-sized elements and monolithic reinforced concrete to the height of the floor. Aerodynamic design of ventilation blocks for kitchens and bathrooms has been performed. The peculiarity of aerodynamic calculation of buildings with a warm attic is shown. Recommendations for the selection of ventilation blocks for residential buildings of various storeys are given. A criterion has been found that makes it possible to predict the trend in the choice of ventilation blocks for residential buildings with a higher number of storeys. © 2023 Author(s)
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