165,347 research outputs found

    KINETICS OF RECOMBINATION PROCESSES

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    In order to solve nonlinear kinetic equations for recombination reactions when the production of participating species is driven externally at a time-dependent rate, the authors establish a framework based on the correspondence between these equations and a Schrodinger-type equation in which the product of the recombination constant with the production rate plays the role of the potential. The required solutions of the kinetic equations can therefore be obtained by solving the equivalent Schrodinger-type equation directly, or by identifying an appropriately chosen time-dependent function as a particular integral of this equation and deducing the production rates with periodic as well as aperiodic time dependences. The approach is seen to reveal a variety of solutions which can be exploited to assist identification of the mechanisms operating and to aid extraction of rate constants in conjunction with the experiment

    Sex differences in the relationship between sensation seeking, trait emotional intelligence and delinquent behaviour

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    Levels of sensation seeking peak in adolescence and there is a well-documented association with delinquency and other risk taking behaviours. The present study investigated the potential moderating effect of trait Emotional Intelligence (EI) on this relationship. Trait EI encompasses high levels of empathy and emotion regulation and is associated with positive outcomes and wellbeing. 96 young adults (48 female; overall Mage = 19.76) completed measures of sensation seeking, trait EI and self-reported delinquent behaviours since age 12. Results indicated that sensation seeking and frequency of delinquent behaviours were positively associated, but this effect was moderated by trait EI for male participants - those with lower trait EI showed a greater increase in delinquency in line with a rise in sensation seeking. No moderation effect was observed for females, and females with higher levels of trait EI reported more delinquent behaviours. The results are discussed in terms of the protective role of trait EI in supporting self-regulation and whether, for some females, high levels of EI might predispose to antisocial relational behaviours

    THEORY OF DIFFUSION OF HEAVY IMPURITIES IN ALKALI-METALS

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    Interatomic potentials have been developed for heavy atom impurities in alkali metal hosts, and they have been used to calculate characteristic energies for the diffusion of gold in sodium and of silver in lithium. The calculations show that, whilst most impurity atoms should be present substitutionally, the diffusion is dominated by interstitial motion for both Li-Ag and Na-Au. The large difference in observed behaviour stems from the different forms of the interatomic potentials but cannot be described simply in terms of atomic radii or electronegativity arguments. The activation energies predicted are in good quantitative agreement with experiment

    Properties of the amniotic membrane for potential use in tissue engineering

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    An important component of tissue engineering (TE) is the supporting matrix upon which cells and tissues grow, also known as the scaffold. Scaffolds must easily integrate with host tissue and provide an excellent environment for cell growth and differentiation. Most scaffold materials are naturally derived from mammalian tissues. The amniotic membrane (AM) is considered an important potential source for scaffolding material. The AM represents the innermost layer of the placenta and is composed of a single epithelial layer, a thick basement membrane and an avascular stroma. The special structure and biological viability of the AM allows it to be an ideal candidate for creating scaffolds used in TE. Epithelial cells derived from the AM have the advantages of stem cells, yet are a more suitable source of cells for TE than stem cells. The extracellular matrix components of the basement membrane of the AM create an almost native scaffold for cell seeding in TE. In addition, the AM has other biological properties important for TE, including anti-inflammatory, anti-microbial, anti-fibrosis, anti-scarring, as well as reasonable mechanical property and low immunogenicity. In this review, the various properties of the AM are discussed in light of their potential use for TE

    Multiple description video coding for stereoscopic 3D

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    In this paper, we propose an MDC schemes for stereoscopic 3D video. In the literature, MDC has previously been applied in 2D video but not so much in 3D video. The proposed algorithm enhances the error resilience of the 3D video using the combination of even and odd frame based MDC while retaining good temporal prediction efficiency for video over error-prone networks. Improvements are made to the original even and odd frame MDC scheme by adding a controllable amount of side information to improve frame interpolation at the decoder. The side information is also sent according to the video sequence motion for further improvement. The performance of the proposed algorithms is evaluated in error free and error prone environments especially for wireless channels. Simulation results show improved performance using the proposed MDC at high error rates compared to the single description coding (SDC) and the original even and odd frame MDC

    Self-assembly in the electrical double layer of ionic liquids

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    We have studied the structure of two ionic liquids confined between negatively charged mica sheets. Both liquids exhibit interfacial layering, however the repeat distance is dramatically different for the two liquids. Our results suggest a transition from alternating cation-anion monolayers to tail-to-tail cation bilayers when the length of the cation hydrocarbon chain is increased

    On design of robust fault detection filter in finite-frequency domain with regional pole assignment

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    This brief is concerned with the fault detection (FD) filter design problem for an uncertain linear discrete-time system in the finite-frequency domain with regional pole assignment. An optimized FD filter is designed such that: 1) the FD dynamics is quadratically D-stable; 2) the effect from the exogenous disturbance on the residual is attenuated with respect to a minimized H∞-norm; and 3) the sensitivity of the residual to the fault is enhanced by means of a maximized H--norm. With the aid of the generalized Kalman-Yakubovich-Popov lemma, the mixed H--/H∞ performance and the D-stability requirement are guaranteed by solving a convex optimization problem. An iterative algorithm for designing the desired FD filter is proposed by evaluating the threshold on the generated residual function. A simulation result is exploited to illustrate the effectiveness of the proposed design technique.This work was supported in part by the Deanship of Scientific Research (DSR) at King Abdulaziz University in Saudi Arabia under Grant 16-135- 35-HiCi, the National Natural Science Foundation of China under Grants 61134009 and 61203139, the Royal Society of the U.K., and the Alexander von Humboldt Foundation of Germany

    Reducing the size and number of linear programs in a dynamic Gr\"obner basis algorithm

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    The dynamic algorithm to compute a Gr\"obner basis is nearly twenty years old, yet it seems to have arrived stillborn; aside from two initial publications, there have been no published followups. One reason for this may be that, at first glance, the added overhead seems to outweigh the benefit; the algorithm must solve many linear programs with many linear constraints. This paper describes two methods of reducing the cost substantially, answering the problem effectively.Comment: 11 figures, of which half are algorithms; submitted to journal for refereeing, December 201
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