Search results for "resolution."
showing 10 items of 1825 documents
Preparing Teachers for Teaching Probability Through Problem Solving
2018
In this paper we introduce the idea of solving problems by simulation with didactical intention. Based on this idea, we analyse the way we prepare the teachers to teach solving probability problems by simulation, in distinguishing whether the teaching is offered to prospective elementary teachers or secondary school teachers. The process of solving probability problems is seen as an inquiry process, which uses simulation as a resolution method with heuristic content, so that the preparation of teacher is then based on this approach. Therefore, prospective teachers should have the opportunities to learn about probability problems, about the process of solving probability problems, and about …
<title>Surface temperature retrieval from MODIS data</title>
2001
12 MODIS (Moderate Resolution Imaging Spectroradiometer) was launched on board the NASA's Terra Earth Observing System (EOS AM-1) Satellite on December 18, 1999. We propose in this work operative split-window algorithms for retrieving sea surface temperature (SST) and land surface temperature (LST) using MODIS data. In order to attain our goal, the MODTRAN 3.5 radiative transfer code was used to predict radiances for MODIS channels 31 and 32. To analyze atmospheric effects, a set of radiosoundings was used to cover the variability of surface temperature and water vapor concentration on a worldwide scale. These simulated data were split into two sets which have very similar distributions in …
Land Surface Temperature From the Advanced Along-Track Scanning Radiometer: Validation Over Inland Waters and Vegetated Surfaces
2009
The land surface temperature (LST) product of the Advanced Along-Track Scanning Radiometer (AATSR) was validated with ground measurements at the following two thermally homogeneous sites: Lake Tahoe, CA/NV, USA, and a large rice field close to Valencia, Spain. The AATSR LST product is based on the split-window technique using the 11- and 12- mum channels. The algorithm coefficients are provided for 13 different land-cover classes plus one lake class (index i). Coefficients are weighted by the vegetation-cover fraction (f). In the operational implementation of the algorithm, i and f are assigned from a global classification and monthly fractional vegetation-cover maps with spatial resolution…
RADIOISOTOPE MASS SPECTROMETRY
2003
Mass spectrometric methods are very sensitive and enable in many cases a multielement determination of trace and ultratrace elements combined with a good isotopic analysis ( Bacon et al. , 2001 ). Therefore, these techniques are also applied for the detection of long-lived radionuclides ( Becker and Dietze, 2000 ) mainly in environmental samples ( Adriaens et al. , 1992 ; Bailey et al. , 1993 ; Bibler et al. , 1998 ; Eroglu et al. , 1998 ; Edmonds et al. , 1998 ; Becker and Dietze, 1999 ; Wendt et al. , 1999 ), nuclear materials ( Betti, 1997 ; Chartier et al. , 1999 ), glass and ceramics ( Rohr et al. , 1994 ; Fukuda and Sayama, 1997 ), and in high-purity substances ( Beer and Heumann, 199…
High-sensitivity U–Pb rutile dating by secondary ion mass spectrometry (SIMS) with an O2+ primary beam
2012
Abstract We present a secondary ionization mass spectrometry (SIMS) technique for U–Pb geochronology of rutile at high spatial resolution and sensitivity using an O2+ primary ion beam coupled with surficial O2 gas deposition (O2 flooding). The O2+ beam is ~ 10 × more intense than conventionally applied O− or O2− beams at the same lateral resolution. Natural and synthetic rutile was determined to be conductive under O2+ bombardment, permitting higher excavation (sputter) rates than conventional SIMS using negatively charged O-beams without detrimental effects of sample charging. The main advantage of O2+ is rapid sputtering at shallow primary ion penetration depths. This minimizes the contri…
Structure determination and homogeneous optical properties of CdS/HgS quantum dots
1997
The structural and optical properties of heterogeneous semiconductor nanoparticles consisting of CdS and HgS are investigated by High Resolution Electron Microscopy (HRTEM) and selective spectroscopy like Hole Burning (HB) and Fluorescence Line Narrowing (FLN). The HRTEM study shows that epitaxy is possible in nanocrystals, provided the crystallites have well defined faceted shapes to begin with. From the HB- and FLN experiments homogeneous absorption and fluorescence spectra are calculated. It could be shown that the absorption is coupled to HgS-like phonons (250 cm -1 ) whereas the emission frequency is closer to the LO phonon frequency of CdS.
New Results from the NUMEN Project
2018
International audience; NUMEN aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0νββ), by high-accuracy measurements of the cross sections of Heavy Ion (HI) induced Double Charge Exchange (DCE) reactions. First evidence about the possibility to get quantitative information about NME from experiments is found for the (^18O,^18Ne) and (^20Ne,^20O) reactions. Moreover, to infer the neutrino average masses from the possible measurement of the half-life of 0νββ decay, the knowledge of the NME is a crucial aspect. The key tools for this project are the high resolution Superconducting Cyclotron beam…
Time Series Corrections and Analyses in Thermal Remote Sensing
2013
The time span of surface thermal data bases now reaches a few decades. However, studies using surface thermal time series are seldom, due to the difficulty of obtaining temporally coherent estimations for this parameter. Applications for surface thermal multitemporal analysis range from climate change studies and modeling to anomaly detection for natural or industrial hazard detection. This chapter presents methods to improve the temporal coherence of temperature time series, through data reconstruction of atmospheric and cloud contaminated observations, and through the correction of the orbital drift effect which hinders the use of the longest data sets. Then, methods for the analysis of t…
Episodios térmicos extremos analizados con productos MODIS durante el invierno boreal (2000-2016)
2016
<p>The beginning of the XXI century is characterized by the intensification of the existing global warming situation and for a series of drastic global meteorological events. Particularly, during the winter season a series of extreme temperature episodes affecting large areas of the northern hemisphere have been produced. In this paper, these episodes are studied by analyzing the thermal anomalies spatial distribution and temporal evolution in the period 2001-2016 from Land Surface Temperature (LST) products obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. The study regions considered in this investigation are eight of the northern hemisphere. The result…
Algorithms for transforming an integral photography into a plenoptic picture
2013
We report a simple algorithm for transforming the set of elemental images captured with an integral-photography set up, into the set of micro-images ready to be projected into an integral-imaging monitor. The method is based in the transposing relation between an integral photography and a plenoptic picture. The reported technique permits to adapt the integral images to the resolution and size of the monitor.