163 research outputs found

    Gas-sensitive properties of oxide systems based on ln203 and Sn02 obtained by sol-gel technology

    Get PDF
    The influence of structural features of ln203, Sn02, Mo03 and Fe203 simple oxides and their composites on the properties of the corresponding semiconductor gas sensors with regards to different gases (CO, CH4, NH3, C2H5OH, CH3OH, NO, N02, 03) have been studied. Structural peculiarities of oxide systems obtained by sol-gel technology have been considered. It was shown the possibility to control the sensor sensitivity to the mentioned above gases by varying chemical composition of sensitive materials and adjusting their structure, as well as by regulat-ing of detecting temperatur

    Exotic torus manifolds and equivariant smooth structures on quasitoric manifolds

    Full text link
    In 2006 Masuda and Suh asked if two compact non-singular toric varieties having isomorphic cohomology rings are homeomorphic. In the first part of this paper we discuss this question for topological generalizations of toric varieties, so-called torus manifolds. For example we show that there are homotopy equivalent torus manifolds which are not homeomorphic. Moreover, we characterize those groups which appear as the fundamental groups of locally standard torus manifolds. In the second part we give a classification of quasitoric manifolds and certain six-dimensional torus manifolds up to equivariant diffeomorphism. In the third part we enumerate the number of conjugacy classes of tori in the diffeomorphism group of torus manifolds. For torus manifolds of dimension greater than six there are always infinitely many conjugacy classes. We give examples which show that this does not hold for six-dimensional torus manifolds.Comment: 21 pages, 2 figures, results about quasitoric manifolds adde

    Plaquette operators used in the rigorous study of ground-states of the Periodic Anderson Model in D=2D = 2 dimensions

    Full text link
    The derivation procedure of exact ground-states for the periodic Anderson model (PAM) in restricted regions of the parameter space and D=2 dimensions using plaquette operators is presented in detail. Using this procedure, we are reporting for the first time exact ground-states for PAM in 2D and finite value of the interaction, whose presence do not require the next to nearest neighbor extension terms in the Hamiltonian. In order to do this, a completely new type of plaquette operator is introduced for PAM, based on which a new localized phase is deduced whose physical properties are analyzed in detail. The obtained results provide exact theoretical data which can be used for the understanding of system properties leading to metal-insulator transitions, strongly debated in recent publications in the frame of PAM. In the described case, the lost of the localization character is connected to the break-down of the long-range density-density correlations rather than Kondo physics.Comment: 34 pages, 5 figure

    Further restrictions on the topology of stationary black holes in five dimensions

    Full text link
    We place further restriction on the possible topology of stationary asymptotically flat vacuum black holes in 5 spacetime dimensions. We prove that the horizon manifold can be either a connected sum of Lens spaces and "handles" S1×S2S^1 \times S^2, or the quotient of S3S^3 by certain finite groups of isometries (with no "handles"). The resulting horizon topologies include Prism manifolds and quotients of the Poincare homology sphere. We also show that the topology of the domain of outer communication is a cartesian product of the time direction with a finite connected sum of R4,S2×S2\mathbb R^4,S^2 \times S^2's and CP2CP^2's, minus the black hole itself. We do not assume the existence of any Killing vector beside the asymptotically timelike one required by definition for stationarity.Comment: LaTex, 22 pages, 9 figure

    Remarks on the classification of quasitoric manifolds up to equivariant homeomorphism

    Full text link
    We give three sufficient criteria for two quasitoric manifolds (M,M') to be (weakly) equivariantly homeomorphic. We apply these criteria to count the weakly equivariant homeomorphism types of quasitoric manifolds with a given cohomology ring.Comment: 11 page

    Nanopores: maltoporin channel as a sensor for maltodextrin and lambda-phage

    Get PDF
    BACKGROUND: To harvest nutrition from the outside bacteria e.g. E. coli developed in the outer cell wall a number of sophisticated channels called porins. One of them, maltoporin, is a passive specific channel for the maltodextrin uptake. This channel was also named LamB as the bacterial virus phage Lambda mis-uses this channel to recognise the bacteria. The first step is a reversible binding followed after a lag phase by DNA injection. To date little is known about the binding capacity and less on the DNA injection mechanism. To elucidate the mechanism and to show the sensitivity of our method we reconstituted maltoporin in planar lipid membranes. Application of an external transmembrane electric field causes an ion current across the channel. Maltoporin channel diameter is around a few Angstroem. At this size the ion current is extremely sensitive to any modification of the channels surface. Protein conformational changes, substrate binding etc will cause fluctuations reflecting the molecular interactions with the channel wall. The recent improvement in ion current fluctuation analysis allows now studying the interaction of solutes with the channel on a single molecular level. RESULTS: We could demonstrate the asymmetry of the bacterial phage Lambda binding to its natural receptor maltoporin. CONCLUSION: We suggest that this type of measurement can be used as a new type of biosensors

    Military spending and economic growth in China: a regime-switching analysis

    Get PDF
    This article has been made available through the Brunel Open Access Publishing Fund.This article investigates the impact of military spending changes on economic growth in China over the period 1953 to 2010. Using two-state Markov-switching specifications, the results suggest that the relationship between military spending changes and economic growth is state dependent. Specifically, the results show that military spending changes affect the economic growth negatively during a slower growth-higher variance state, while positively within a faster growth-lower variance one. It is also demonstrated that military spending changes contain information about the growth transition probabilities. As a policy tool, the results indicate that increases in military spending can be detrimental to growth during slower growth-higher growth volatility periods. © 2014 © 2014 The Author(s). Published by Taylor & Francis

    5-dimensional contact SO(3)-manifolds and Dehn twists

    Full text link
    In this paper the 5-dimensional contact SO(3)-manifolds are classified up to equivariant contactomorphisms. The construction of such manifolds with singular orbits requires the use of generalized Dehn twists. We show as an application that all simply connected 5-manifoldswith singular orbits are realized by a Brieskorn manifold with exponents (k,2,2,2). The standard contact structure on such a manifold gives right-handed Dehn twists, and a second contact structure defined in the article gives left-handed twists.Comment: 16 pages, 1 figure; simplification of arguments by restricting classification to coorientation preserving contactomorphism

    Properties of 3-manifolds for relativists

    Full text link
    In canonical quantum gravity certain topological properties of 3-manifolds are of interest. This article gives an account of those properties which have so far received sufficient attention, especially those concerning the diffeomorphism groups of 3-manifolds. We give a summary of these properties and list some old and new results concerning them. The appendix contains a discussion of the group of large diffeomorphisms of the ll-handle 3-manifold.Comment: 20 pages. Plain-TeX, no figures, 1 Table (A4 format

    Acting together: ensemble as a democratic process in art and life

    Get PDF
    Traditionally drama in schools has been seen either as a learning medium with a wide range of curricular uses or as a subject in its own right. This paper argues that the importance of drama in schools is in the processes of social and artistic engagement and experiencing of drama rather than in its outcomes. The paper contrasts the pro-social emphasis in the ensemble model of drama with the pro-technical and limited range of learning in subject-based approaches which foreground technical knowledge of periods, plays, styles and genres. The ensemble-based approach is positioned in the context of professional theatre understandings of ensemble artistry and in the context of revolutionary shifts from the pro-technical to the pro-social in educational and cultural policy making in England. Using ideas drawn from McGrath and Castoriadis, the paper claims that the ensemble approach provides young people with a model of democratic living
    corecore