997 resultados para 502


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国家自然科学基金(编号:40573014;40373030);中国科学院“百人计划”项目

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研究角砾岩的目的是把它作为一个"窗口",进而研究已知角砾岩体与成矿的关系,研究它们的产出条件和地质背景,以其为类比对象而进行成矿预测.预测的对象和空间范围不完全局限于仅由角砾岩体揭示出的某些地段,也包括分析推断而有利于和(或)相当于角砾岩产出的某些地段(史明魁和苟月明,2000).研究安徽月山矿田三叠系月山组角砾岩与成矿的关系旨在为第二轮找矿预测提供依据.

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Fibrosis caused by the host response to long-term transplanted microcapsules and the limitation of traditional L929 cell model for biocompatibility testing inspire the development of an assay of biocompatibility based on macrophage behavior. In this paper, the human monocytic cell line THP-1 was utilized for biocompatibility evaluation of microcapsule materials. The cell viability and secretion of nitric oxide (NO) and cytokines served as index of biocompatibility were assayed. It was found that the evaluated microcapsule materials had no effect on the stimulation of NO and cytokines secretion, which meant that these materials were biocompatible. Furthermore, it suggests the THP-1 cell a convenient in vitro experimental model that might be useful for long-term predictions of material biocompatibility.

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Clonal selection has been a dominant theme in many immune-inspired algorithms applied to machine learning and optimisation. We examine existing clonal selections algorithms for learning from a theoertical and empirical perspective and assert that the widely accepted computational interpretation of clonal selection is compromised both algorithmically andbiologically. We suggest a more capable abstraction of the clonal selection principle grounded in probabilistic estimation and approximation and demonstrate how it addresses some of the shortcomings in existing algorithms. We further show that by recasting black-box optimisation as a learning problem, the same abstraction may be re-employed; thereby taking steps toward unifying the clonal selection principle and distinguishing it from natural selection.

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Li, Longzhuang, Liu, Yonghuai, Obregon, A., Weatherston, M. Visual Segmentation-Based Data Record Extraction From Web Documents. Proceedings of IEEE International Conference on Information Reuse and Integration, 2007, pp. 502-507. Sponsorship: IEEE

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Grande, Manuel; Kellett, B.; Howe, C.; Perry, C.H., 'The D-CIXS X-ray spectrometer on the SMART-1 mission to the Moon - First Results', Planetary And Space Science (2007) 55(4) pp.494-502 RAE2008

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Gaussian factor models have proven widely useful for parsimoniously characterizing dependence in multivariate data. There is a rich literature on their extension to mixed categorical and continuous variables, using latent Gaussian variables or through generalized latent trait models acommodating measurements in the exponential family. However, when generalizing to non-Gaussian measured variables the latent variables typically influence both the dependence structure and the form of the marginal distributions, complicating interpretation and introducing artifacts. To address this problem we propose a novel class of Bayesian Gaussian copula factor models which decouple the latent factors from the marginal distributions. A semiparametric specification for the marginals based on the extended rank likelihood yields straightforward implementation and substantial computational gains. We provide new theoretical and empirical justifications for using this likelihood in Bayesian inference. We propose new default priors for the factor loadings and develop efficient parameter-expanded Gibbs sampling for posterior computation. The methods are evaluated through simulations and applied to a dataset in political science. The models in this paper are implemented in the R package bfa.

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El taller “El análisis didáctico: una posibilidad de integración curricular” tiene como propósito socializar con la comunidad académica los procesos de construcción curricular que colectivamente se ha venido tejiendo para la licenciatura en Matemáticas y Física de la Universidad de la Amazonia, Caquetá, Colombia, en la que se asume el análisis didáctico como un proceso metodológico transversal que potencia el diálogo de los conocimientos de las disciplinas escolares (Matemáticas y Física) con sus respectivos problemas de aula (Didácticas específicas) como posibilidad de reconocer las prácticas de enseñanza y de aprendizaje de las matemáticas y la física, de problematizar y de actuar en ella con propuestas alternativas en las que la docencia y la investigación permiten redimensionar el rol del maestro en formación.

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The attachment of electronic components to printed circuit boards using solder material is a complex process. This paper presents a novel modeling methodology, which integrates the governing physics taking place. Multiphysics modeling technology, imbedded into the simulation tool—PHYSICA is used to simulate fluid flow, heat transfer, solidification, and stress evolution in an integrated manner. Results using this code are presented, detailing the mechanical response of two solder materials as they cool, solidify and then deform. The shape that a solder joint takes upon melting is predicted using the SURFACE EVOLVER code. Details are given on how these predictions can be used in the PHYSICA code to provide a modeling route by which the shape, solidification history, and resulting stress profiles can be predicted.

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The aim of this paper is to develop a mathematical model with the ability to predict particle degradation during dilute phase pneumatic conveying. A numerical procedure, based on a matrix representation of degradation processes, is presented to determine the particle impact degradation propensity from a small number of particle single impact tests carried out in a new designed laboratory scale degradation tester. A complete model of particle degradation during dilute phase pneumatic conveying is then described, where the calculation of degradation propensity is coupled with a flow model of the solids and gas phases in the pipeline. Numerical results are presented for degradation of granulated sugar in an industrial scale pneumatic conveyor.