2,195 research outputs found
Photoelectro-chemical properties of anilino squaraine derivatives in LB films
No full textPhotocurrent generation from Langmuir-Blodgett (LB) overlays on indium tin oxide (ITO) electrodes, where the active components are 2,4-bis[4-(dibutylamino)-2-hydroxyphenyl]squaraine (1) and the unsubstituted analogue, 2,4-bis[4-(dibutylamino)phenyl]squaraine (2), have been investigated. Dye 1 shows improved behaviour compared with the latter and differences in performance are attributed to a modified aggregate structure, this being indicated by variations in the LB film spectra. The photocurrent generation is enhanced by the presence of electron accepters, e.g. N,N'-dimethyl-4,4'-bipyridinium diiodide (MV2+), but quenched by electron donors, e.g. hydroquinone (HQ). The concentration dependence is reported
Comments on author citations for nomenclatural novelties published in volume 15 of the Flora Reipublicae Popularis Sinicae (FRPS)
No full textLearning theories and interprofessional education: a user's guide
No full textThere is increasing interest in the theoretical underpinning of interprofessional education (IPE) and writers in this field are drawing on a wide range of disciplines for theories that have utility in IPE. While this has undoubtedly enriched the research literature, for the educational practitioner, whose aim is to develop and deliver an IPE curriculum that has sound theoretical underpinnings, this plethora of theories has become a confusing, and un-navigable quagmire. This article aims to provide a compass for those educational practitioners by presenting a framework that summarizes key learning theories used in IPE and the relationship between them. The study reviews key contemporary learning theories from the wider field of education used in IPE and the explicit applications of these theories in the IPE literature to either curriculum design or programme evaluation. Through presenting a broad overview and summary framework, the study clarifies the way in which learning theories can aid IPE curriculum development and evaluation. It also highlights areas where future theoretical development in the IPE field is required
Photoelectrochemistry of Langmuir-Blodgett films of a C-60 iminodiacetic acid ester derivative on ITO electrodes
No full textThe photoelectrochemical response of a C-60 iminodiacetic acid ester derivative (C(60)IDA), deposited on ITO electrodes by means of the Langmuir-Blodgett technique, has been investigated. The anodic photocurrent observed on the modified electrode corresponds to an electron transfer from the electrolyte through the LB film to the electrode. The action spectrum of photocurrent indicates C60IDA as the photoactive species in the photoinduced electron transfer process. Positive bias voltage, reducing agent and higher pH of the solution are beneficial factors for generating higher photocurrent. The quantum yield for photocurrent generation is 0.94% and can be raised to 3.40% under favorable conditions. (C) 1998 Elsevier Science S.A. All rights reserved.Materials Science, MultidisciplinaryPhysics, Condensed MatterPolymer ScienceSCI(E)EI9ARTICLE3223-2279
Factorization of weakly compact operators between Banach spaces and Fréchet or (LB)-spaces
No full text[EN] In this note we show that weakly compact operators from a Banach space X into
a complete (LB)-space E need not factorize through a reflexive Banach space. If E is a Fréchet space, then weakly compact operators from a Banach space X into E factorize through a reflexive Banach space. The factorization of operators from a Fréchet or a complete (LB)-space into a Banach space mapping bounded sets into relatively weakly compact sets is also investigated.The research of the first author was partially supported by MEC and FEDER Project MTM2010-15200 and by GV Project Prometeo/2008/101. The support of the University of Aberdeen and the Universidad Polit´ecnica of Valencia is gratefully acknowledged.Bonet Solves, JA.; Wright, JM. (2012). Factorization of weakly compact operators between Banach spaces and Fréchet or (LB)-spaces. Matematicki Vesnik. 64(4):330-335. https://riunet.upv.es/handle/10251/58753S33033564
Simulating liquid droplets: A quantitative assessment of lattice Boltzmann and Volume of Fluid methods
No full textWhile various multiphase flow simulation techniques have found acceptance as predictive tools for processes involving immiscible fluids, none of them can be considered universally applicable. Focusing on accurate simulation of liquid-liquid emulsions at the scale of droplets, we present a comparative assessment of the single-component multiphase pseudopotential lattice Boltzmann method (PP-LB, classical and modified) and the Volume of Fluid method (VOF, classical and modified), highlighting particular strengths and weaknesses of these techniques. We show that a modified LB model produces spurious velocities 1–3 orders of magnitude lower than all VOF models tested, and find that LB is roughly 10 times faster in computation time, while VOF is more versatile. Simulating falling liquid droplets, a realistic problem, we find that despite identical setups, results can vary with the technique in certain flow regimes. At lower Reynolds numbers, all methods agree reasonably well with experimental values. At higher Reynolds numbers, all methods underpredict the droplet Reynolds number, while being in good agreement with each other. Particular issues regarding LB simulations at low density ratio are emphasized. Finally, we conclude with the applicability of VOF vis-à-vis PP-LB for a general range of multiphase flow problems relevant to myriad applications.Accepted Author ManuscriptChemE/Transport PhenomenaIntensified Reaction and Separation System
Nonadaptive Amino Acid Convergence Rates Decrease over Time.
No full textConvergence is a central concept in evolutionary studies because it provides strong evidence for adaptation. It also provides information about the nature of the fitness landscape and the repeatability of evolution, and can mislead phylogenetic inference. To understand the role of adaptive convergence, we need to understand the patterns of nonadaptive convergence. Here, we consider the relationship between nonadaptive convergence and divergence in mitochondrial and model proteins. Surprisingly, nonadaptive convergence is much more common than expected in closely related organisms, falling off as organisms diverge. The extent of the convergent drop-off in mitochondrial proteins is well predicted by epistatic or coevolutionary effects in our "evolutionary Stokes shift" models and poorly predicted by conventional evolutionary models. Convergence probabilities decrease dramatically if the ancestral amino acids of branches being compared have diverged, but also drop slowly over evolutionary time even if the ancestral amino acids have not substituted. Convergence probabilities drop-off rapidly for quickly evolving sites, but much more slowly for slowly evolving sites. Furthermore, once sites have diverged their convergence probabilities are extremely low and indistinguishable from convergence levels at randomized sites. These results indicate that we cannot assume that excessive convergence early on is necessarily adaptive. This new understanding should help us to better discriminate adaptive from nonadaptive convergence and develop more relevant evolutionary models with improved validity for phylogenetic inference
Constructing different 'bridges' for interfacial electron transfer in azobenzene LB/SAM composite bilayers
No full textTwo methods, Langmuir-Blodgett (LB) and self-assembly (SA), were used in the present work to fabricate certain interfacial structures for the study of long-range electron transfer. We have successfully constructed two different 'bridges' for the interfacial electron transfer in azobenzene LB/SAM composite bilayer systems. One has ionic bonding character, while the other has face-to-face hydrogen bonding at the interface of an ABD (4-octyl-4'-(3-carboxy-trimethylene-oxy)-azobenzene) LB monolayer and the underlying aminothiol SAM. These structures have been confirmed by using RA-FTIR and contact angle titration. Furthermore, the apparent electron transfer rate across the ionic bonding 'bridge' is much more rapid than in the hydrogen-bonded case, indicating that the interfacial structure plays a crucial role in the long-range electron transfer kinetics. (C) 1998 Elsevier Science S.A. All rights reserved.Chemistry, AnalyticalElectrochemistrySCI(E)EI14ARTICLE1119-12444
EFFECT OF CHEMICAL-POTENTIAL SHIFT ON THERMODYNAMICAL PROPERTIES OF THE MIXED-VALENCE COMPOUNDS
No full textStarting from the SU(N(d)) Anderson lattice model in the slave boson formalism, we study the effect of the chemical potential shift on the thermodynamic properties of the mixed valence lattice system by using the Green's function technique. In the mean field approximation, the self-consistent equations of the mean field parameters and the chemical potential are obtained. The average number of f electrons, the magnetic susceptibility and the specific heat are calculated. The numerical studies show that the shift of the chemical potential has a strong effect on the thermodynamic properties.Physics, MultidisciplinarySCI(E)中国科学引文数据库(CSCD)1ARTICLE2147-1542
Electroluminescence from dysprosium- and neodymium-containing LB films
No full textIn this paper we report on electroluminescence from Langmuir-Blodgett (LB) films of two navel molecular complexes originally developed for non-linear optics applications containing neodymium and dysprosium trivalent rare earth ions. The two molecular complexes have a structure which consists of a donor pi-pi* conjugated cation ionically coupled to a complex anion consisting of a trivalent rare earth ion surrounded by four singly charged pyrazolone ligands. The two materials are identical apart from the presence of either dysprosium or neodymium ions at the centre of the complex anions. LB films of the complexes produced on glass/indium tin oxide substrates produce broad electroluminescence in the visible region of the spectrum which is considerably red-shifted relative to their photoluminescence. The electroluminescent devices prepared operate in vacuo and at room temperature. The characteristic emissions associated with the rare earth ions themselves, observed as a result of photoexcitation, cannot be excited electrically.Materials Science, MultidisciplinaryMaterials Science, Coatings & FilmsPhysics, AppliedPhysics, Condensed MatterSCI(E)
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