999 resultados para areal type
Resumo:
The effects of the relative phase between two laser beams on the propagation of a weak electromagnetic pulse are investigated in a V-type system with spontaneously generated coherence (SGC). Due to the relative phase, the subluminal and superluminal group velocity can be unified. Meanwhile, SGC can be regarded as a knob to manipulate light propagation between subluminal and superluminal.
Resumo:
With the external field coupling the two upper levels, we investigate the light pulse propagation properties with weak probe field in a V-type system. Due to the external upper level (UL) coupling field, the dispersion of the system has been influenced by the relative phase. It is shown that the UL field and the relative phase can be regarded as switches to manipulate light propagation between subluminal and superluminal. (c) 2007 Elsevier B.V. All rights reserved.
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The properties of a five-level K-type system are investigated. With the controlling fields, the properties of the dispersion and absorption of the system are changed greatly. The system can produce anomalous dispersion regions with absorption and normal dispersion regions with absorption or transparency. Furthermore, the group velocity can be varied from subluminal to superluminal by varying the intensity of the controlling field and the probe detunings in principle. (C) 2008 Elsevier B.V. All rights reserved.
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Part I
The mechanism of the hydroformylation reaction was studied. Using cobalt deuterotetracarbonyl and 1-pentene as substrates, the first step in the reaction, addition of cobalt tetracarbonyl to an olefin, was shown to be reversible.
Part II
The role of coenzyme B12 in the isomerization of methylmalonyl coenzyme A to succinyl coenzyme A by methylmalonyl coenzyme A mutase was studied. The reaction was allowed to proceed to partial completion using a mixture of methylmalonyl coenzyme A and 4, 4, 4-tri-2H-methylmalonyl coenzyme A as substrate. The deuterium distribution in the product, succinyl coenzyme A, was shown to best fit a model in which hydrogen is transferred from C-4 of methylmalonyl coenzyme A to C-5’ of the adenosyl moiety of coenzyme B12 in the rate determining step. The three hydrogens at the 5’-adenosyl position of the coenzyme B12 intermediate are then able to become enzymatically equivalent before hydrogen is transferred from the coenzyme B12 intermediate to form succinyl coenzyme A.
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El objetivo principal de esta tesis doctoral es, en primer lugar, ofrecer una reconstrucción alternativa del protoainu para, en segundo lugar, aplicar conceptos de tipología diacrónicaholística con el fin de discernir algún patrón evolutivo que ayude a responder a la pregunta:¿por qué la lengua ainu es como es en su contexto geolingüístico (lengua AOV con prefijos),cuando en la región euroasiática lo normal es encontrar el perfil 'lengua AOV con sufijos'? En suma, se trata de explorar las posibilidades que ofrece la tipología diacrónica holística,combinada con métodos más tradicionales, en la investigación de las etapas prehistóricas delenguas aisladas, es decir, sin parientes conocidos, como el ainu, el vasco, el zuñi o elburushaski. Este trabajo se divide en tres grandes bloques con un total de ocho capítulos, unapéndice con las nuevas reconstrucciones protoainúes y la bibliografía.El primer bloque se abre con el capítulo 1, donde se hace una breve presentación delas lenguas ainus y su filología. El capítulo 2 está dedicado a la reconstrucción de la fonologíaprotoainu. La reconstrucción pionera pertenece a A. Vovin (1992), que de hecho sirve comobase sobre la que ampliar, corregir o modificar nuevos elementos. En el capítulo 3 se describela morfología histórica de las lenguas ainus. En el capítulo 4 se investiga esta opción dentrode un marco más amplio que tiene como objetivo analizar los patrones elementales deformación de palabras. El capítulo 5, con el que se inicia el segundo bloque, da cabida a lapresentación de una hipótesis tipológica diacrónica, a cargo de P. Donegan y D. Stampe, conla que especialistas en lenguas munda y mon-khmer han sido capaces de alcanzar unreconstrucción del protoaustroasiático según la cual el tipo aglutinante de las lenguas mundasería secundario, frente al original monosilábico de las lenguas mon-khmer. En el capítulo 6se retoma la perspectiva tradicional de la lingüística geográfica, pero no se olvidan algunas delas consideraciones tipológicas apuntadas en el capítulo anterior (el hecho de que la hipótesisde Donegan y Stampe no funcione con el ainu no significa que la tipología diacrónica nopueda ser todavía de utilidad). En el capítulo 7 se presentan algunas incongruencias queresultan tras combinar las supuestas evidencias arqueológicas con el escenario lingüísticodescrito en capítulos anteriores. Las conclusiones generales se presentan en el capítulo 8. Elapéndice es una tabla comparativa con las dos reconstrucciones disponibles a fecha de hoypara la lengua protoainu, es decir, las propuestas por A. Vovin en su estudio seminal de 1992y en el capítulo 3 de la presente tesis. Dicha tabla incluye 686 reconstrucciones (puedehacerse una sencilla referencia cruzada con Vovin, puesto que ambas están ordenadasalfabéticamente).
Resumo:
Broad bandwidth group match conditions are reported for a noncollinear type I optical parametric process. The theoretical calculations corresponding to two special situations in practice were made, respectively, which are in accordance with the published experimental results. Furthermore, we provide a method to not only achieve maximal parametric bandwidth output but also match the group velocities between three waves. (c) 2006 Optical Society of America.
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A relatively simple scheme for disk-type photopolymer high-density holographic storage based on angular and spatial multiplexing is described. The effects of the optical setup on the recording capacity and density are studied. Calculations and analysis show that this scheme is more effective than a scheme based on the spatioangular multiplexing for disk-type photopolymer high-density holographic storage, which has a limited medium thickness. Also an optimal beam recording angle exists to achieve maximum recording capacity and density. (C) 2002 Society of Photo-Optical Instrumentation Engineers.
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The conventional TbFeCo magneto-optical (MO) medium has a relatively smaller Kerr rotation angle in the blue region than in the red. With the recording wavelength gradually moving to the short wavelength, if TbFeCo is still used as recording medium, the conventional MO disk structure must be optimized to get a larger carrier to noise ratio (CNR). Sabi et al. have found that adding a metal layer attached to the TbFeCo film as thermal control layer is a useful way to get a high CNR. In this paper, we proved this through calculation, and carried out optimization of the new type of disk. Calculation results showed that the new structure is useful in preventing an excessive temperature increase, and has a better thermal response. (c) 2005 Elsevier B.V. All rights reserved.
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Based on the Fresnel-Kirchkoff diffraction theory, we build up a Gaussian diffraction model of metal-oxide-type super-resolution near field structure (super-RENS), which can describe far field optical properties. The spectral contrast induced by refractive index and the structural changes in AgOx, PtOx and PdOx thin films, which are the key functional layers in super-RENS, are studied by using this model. Comparison results indicate that the spectral contrast intensively on laser-induced distribution and change of the refractive index in the metal-oxide films. The readout mechanism of the metal-oxide-type super-RENS optical disc is further clarified. This Gaussian diffraction model can be used as a simple and effective method for choosing proper active materials in super-RENS.
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Background: Type 2 diabetes mellitus is associated with a diverse range of pathologies. The aim of the study was to determine the incidence of diabetes-related complications, the prevalence of coexistent chronic conditions and to report multimorbidity in people with type 2 diabetes living in the Basque Country. Methods: Administrative databases, in four cross sections (annually from 2007 to 2011) were consulted to analyse 149,015 individual records from patients aged >= 35 years with type 2 diabetes mellitus. The data observed were: age, sex, diabetes-related complications (annual rates of acute myocardial infarction, major amputations and avoidable hospitalisations), diabetes-related pathologies (prevalence of ischaemic heart disease, renal failure, stroke, heart failure, peripheral neuropathy, foot ulcers and diabetic retinopathy) and other unrelated pathologies (44 diseases). Results: The annual incidence for each condition progressively decreased during the four-year period: acute myocardial infarction (0.47 to 0.40%), major amputations (0.10 to 0.08%), and avoidable hospitalisations (5.85 to 5.5%). The prevalence for diabetes-related chronic pathologies was: ischaemic heart disease (11.5%), renal failure (8.4%), stroke (7.0%), heart failure (4.3%), peripheral neuropathy (1.3%), foot ulcers (2.0%) and diabetic retinopathy (7.2%). The prevalence of multimorbidity was 90.4%. The highest prevalence for other chronic conditions was 73.7% for hypertension, 13.8% for dyspepsia and 12.7% for anxiety. Conclusions: In the type 2 diabetes mellitus population living in the Basque Country, incidence rates of diabetes complications are not as high as in other places. However, they present a high prevalence of diabetes related and unrelated diseases. Multimorbidity is very common in this group, and is a factor to be taken into account to ensure correct clinical management.
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The aim of this paper is to present fixed point result of mappings satisfying a generalized rational contractive condition in the setup of multiplicative metric spaces. As an application, we obtain a common fixed point of a pair of weakly compatible mappings. Some common fixed point results of pair of rational contractive types mappings involved in cocyclic representation of a nonempty subset of a multiplicative metric space are also obtained. Some examples are presented to support the results proved herein. Our results generalize and extend various results in the existing literature.
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251 p.
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Coincidence and common fixed point theorems for a class of Suzuki hybrid contractions involving two pairs of single-valued and multivalued maps in a metric space are obtained. In addition, the existence of a common solution for a certain class of functional equations arising in a dynamic programming is also discussed.