757 research outputs found

    Laser-induced breakdown spectroscopy associated with multivariate analysis applied to discriminate fertilizers of different nature.

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    Made available in DSpace on 2017-11-24T23:20:19Z (GMT). No. of bitstreams: 1 PLaserinducedbreakdown....pdf: 277933 bytes, checksum: cfd2c91da7bb377fd7e089171b43d4b1 (MD5) Previous issue date: 2017-11-24bitstream/item/167439/1/P-Laser-induced-breakdown....pd

    A review on the formation of heteronuclear cold molecules

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    Is the characterization of biological systems as complex systems in the mathematical sense a fruitful assertion? In this paper we argue in the affirmative, although obviously we do not attempt to confront all the issues raised by this question. We use the fly's visual system as an example and analyse our experimental results of one particular neuron in the fly's visual system from this point of view. We find that the motion-sensitive ‘H1’ neuron, which converts incoming signals into a sequence of identical pulses or ‘spikes’, encodes the information contained in the stimulus into an alphabet composed of a few letters. This encoding occurs on multilayered sets, one of the features attributed to complex systems. The conversion of intervals between consecutive occurrences of spikes into an alphabet requires us to construct a generating partition. This entails a one-to-one correspondence between sequences of spike intervals and words written in the alphabet. The alphabet dynamics is multifractal both with and without stimulus, though the multifractality increases with the stimulus entropy. This is in sharp contrast to models generating independent spike intervals, such as models using Poisson statistics, whose dynamics is monofractal. We embed the support of the probability measure, which describes the distribution of words written in this alphabet, in a two-dimensional space, whose topology can be reproduced by an M-shaped map. This map has positive Lyapunov exponents, indicating a chaotic-like encoding.FAPESPCNP

    Correlated photon-pair generation in a periodically poled MgO doped stoichiometric lithium tantalate reverse proton exchanged waveguide

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    We demonstrate photon-pair generation in a reverse proton exchanged waveguide fabricated on a periodically poled magnesium doped stoichiometric lithium tantalate substrate. Detected pairs are generated via a cascaded second order nonlinear process where a pump laser at wavelength of 1.55 μ\mum is first doubled in frequency by second harmonic generation and subsequently downconverted around the same spectral region. Pairs are detected at a rate of 42 per second with a coincidence to accidental ratio of 0.7. This cascaded pair generation process is similar to four-wave-mixing where two pump photons annihilate and create a correlated photon pair

    Semiquantitative analysis of mercury in landfill leachates using double-pulse laser-induced breakdown spectroscopy.

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    Made available in DSpace on 2017-11-02T09:09:43Z (GMT). No. of bitstreams: 1 PROCI17Semiquantitativeanalysisofmercury....pdf: 746927 bytes, checksum: b75c0ae6928400c1c1207ac3be058399 (MD5) Previous issue date: 2017-10-31bitstream/item/165918/1/PROCI-17-Semiquantitative-analysis-of-mercury....pd
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