4,528 research outputs found

    Evolution of vacancy pores in bounded particles

    Full text link
    In the present work, the behavior of vacancy pore inside of spherical particle is investigated. On the assumption of quasistationarity of diffusion fluxes, the nonlinear equation set was obtained analytically, that describes completely pore behavior inside of spherical particle. Limiting cases of small and large pores are considered. The comparison of numerical results with asymptotic behavior of considered limiting cases of small and large pores is discussed.Comment: 25 pages, 10 figure

    Comparative Assessment of the Factors and Conditions of the Formation of the Neoindustrial Social State in Russia and Germany

    Full text link
    Russia and Germany are traditionally reputed as countries with socially oriented economies. Namely, these countries are also close by the index of the share of real sector of economy at GDP. And however, Germany is a founder of social market household largely defined its leadership in world economy, in current conditions of crisis of “the state of general welfare” the search of a new model of development for Germany is also important as for Russia stood on the way of modernization and neo-industrialization. In the article, the hypothesis about forming of the new model of development uniting the social orientation of economy, processes of neoindustrialization, and globalization is made. At the same time, the social orientation is the main aim of socio-economic development, neo-industrialization is a way to achieve it, and globalization is a criterion presupposing more effective use of resources. Theoretical backgrounds of development of “social state” are generalized in the works of German and Russian classics put the backgrounds of economic humanism, it has allowed to prove the fatality of modernization process without considering of deep mental backgrounds and civilization codes of the nation development. The methodological approaches to development of a new model of neo-industrial social state with emphasizing different levels: global, national, local, individual are worked out; and the technique for estimation of factors and conditions of its development is proposed. The technique is tested on the example of Russia and Germany. The comparative analysis conducted has allowed to make the conclusion about similarity of target guidelines, initial conditions, problems and ways of their solving in these countries, that is to be considered both in a strategy and a policy of socio-economic development of these countries and by their international partnership

    Cation Transport in Polymer Electrolytes: A Microscopic Approach

    Full text link
    A microscopic theory for cation diffusion in polymer electrolytes is presented. Based on a thorough analysis of molecular dynamics simulations on PEO with LiBF4_4 the mechanisms of cation dynamics are characterised. Cation jumps between polymer chains can be identified as renewal processes. This allows us to obtain an explicit expression for the lithium ion diffusion constant D_{Li} by invoking polymer specific properties such as the Rouse dynamics. This extends previous phenomenological and numerical approaches. In particular, the chain length dependence of D_{Li} can be predicted and compared with experimental data. This dependence can be fully understood without referring to entanglement effects.Comment: 4 pages, 4 figures, Physical Review Letters in pres

    Imaging of fuel mixture fraction oscillations in a driven system using acetone PLIF

    Get PDF
    Measurements of fuel mixture fraction are made for a jet flame in an acoustic chamber. Acoustic forcing creates a spatially-uniform, temporally-varying pressure field which results in oscillatory behavior in the flame . Forcing is at 22,27, 32, 37, and 55 Hz. To asses the oscillatory behavior, previous work included chemiluminescence, OH PUF, nitric oxide PUF imaging, and fuel mixture fraction measurements by infrared laser absorption. While these results illuminated what was happening to the flame chemistry, they did not provide a complete explanation as to why these things were happening. In this work, the fuel mixture fraction is measured through PUF of acetone, which is introduced into the fuel stream as a marker. This technique enables a high degree of spatial resolution of fuel/air mixture value. Both non-reacting and reacting cases were measured and comparisons are drawn with the results from the previous work. It is found that structure in the mixture fraction oscillations is a major contributor to the magnitude of the flame oscillations

    Inelastic effects in molecular junctions in the Coulomb and Kondo regimes: Nonequilibrium equation-of-motion approach

    Full text link
    Inelastic effects in the Coulomb blockade and Kondo regimes of electron transport through molecular junctions are considered within a simple nonequilibrium equation-of-motion (EOM) approach. The scheme is self-consistent, and can qualitatively reproduce the main experimental observations of vibrational features in Coulomb blockade [H.Park et al., Nature 407, 57 (2000)] and Kondo [L.H.Yu et al., Phys. Rev. Lett. 93, 266802 (2004)] regimes. Considerations similar to the equilibrium EOM approach by Meir et al. [Phys. Rev. Lett. 66, 3048 (1991); ibid. 70, 2601 (1993)] are used on the Keldysh contour to account for the nonequilibrium nature of the junction, and dressing by appropriate Franck-Condon (FC) factors is used to account for vibrational features. Results of the equilibrium EOM scheme by Meir et al. are reproduced in the appropriate limit.Comment: 12 pages, 5 figure

    Combinations of isoform-targeted histone deacetylase inhibitors and bryostatin analogues display remarkable potency to activate latent HIV without global T-cell activation

    Get PDF
    AbstractCurrent antiretroviral therapy (ART) for HIV/AIDS slows disease progression by reducing viral loads and increasing CD4 counts. Yet ART is not curative due to the persistence of CD4+ T-cell proviral reservoirs that chronically resupply active virus. Elimination of these reservoirs through the administration of synergistic combinations of latency reversing agents (LRAs), such as histone deacetylase (HDAC) inhibitors and protein kinase C (PKC) modulators, provides a promising strategy to reduce if not eradicate the viral reservoir. Here, we demonstrate that largazole and its analogues are isoform-targeted histone deacetylase inhibitors and potent LRAs. Significantly, these isoform-targeted HDAC inhibitors synergize with PKC modulators, namely bryostatin-1 analogues (bryologs). Implementation of this unprecedented LRA combination induces HIV-1 reactivation to unparalleled levels and avoids global T-cell activation within resting CD4+ T-cells.</jats:p

    Ion and polymer dynamics in polymer electrolytes PPO-LiClO4: II. 2H and 7Li NMR stimulated-echo experiment

    Full text link
    We use 2H NMR stimulated-echo spectroscopy to measure two-time correlation functions characterizing the polymer segmental motion in polymer electrolytes PPO-LiClO4 near the glass transition temperature Tg. To investigate effects of the salt on the polymer dynamics, we compare results for different ether oxygen to lithium ratios, namely, 6:1, 15:1, 30:1 and infinity. For all compositions, we find nonexponential correlation functions, which can be described by a Kohlrausch function. The mean correlation times show quantitatively that an increase of the salt concentration results in a strong slowing down of the segmental motion. Consistently, for the high 6:1 salt concentration, a high apparent activation energy E_a=4.1eV characterizes the temperature dependence of the mean correlation times at Tg < T< 1.1T_g, while smaller values E_a=2.5eV are observed for moderate salt contents. The correlation functions are most nonexponential for 15:1 PPO-LiClO4, whereas the stretching is reduced for higher and lower salt concentrations. A similar dependence of the correlation functions on the evolution time in the presence and in the absence of ions indicates that addition of salt hardly affects the reorientational mechanism. For all compositions, mean jump angles of about 15 degree characterize the segmental reorientation. In addition, comparison of results from 2H and 7Li NMR stimulated-echo experiments suggests a coupling of ion and polymer dynamics in 15:1 PPO-LiClO4.Comment: 14 pages, 12 figure
    corecore