977 resultados para Termoluminescência (TL)


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Biometric relationships were recorded for 2431 male and female Panulirus echinatus sampled at Tamandare coastal reefs, Pernambuco, Brazil. The following body measurements were taken: carapace length and width, abdomen length and width, total length, third and fifth pereiopod length, cephalothorax-abdomen and total weight. Twelve relationships were studied to compare the biometric characteristics Of males and females. Eleven of them showed difference between the sexes. Comparing sexes with the same carapace length, males have a heavier cephalothorax and longer third and fifth pereiopods than females, whereas females are longer, wider, and have a heavier abdomen than males. For genders with the same total length, males are heavier and have a longer carapace than females, while females have a larger abdomen. For genders with the same abdomen length, males have a heavier abdomen than females. The relationships TWg/TL and A Wg/AL showed positive allometric growth for the males. All other relationships involving weight, presented negative allometric growth for both sexes.

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The fading of persistent luminescence in Sr2MgSi2O7:Eu2+,R3+ (R: Y, La-Nd, Sm-Lu) was studied combining thermoluminescence (TL) and room temperature (persistent) luminescence measurements to gain more information on the mechanism of persistent luminescence. The TL glow curves showed the main trap signal at ca. 80 degrees C, corresponding to 0.6 eV as the trap depth, with every R co-dopant. The TL measurements carried out with different irradiation times revealed the general order nature of the TL bands. The results obtained from the deconvolutions of the glow curves allowed the prediction of the fading of persistent luminescence with good accuracy, though only when using the Becquerel decay law. (C) 2012 Optical Society of America

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The hydrolysis of pyridoxalrhodanine in a basic medium containing the dimethylthallium(III) cation afforded the compound [TlMe2(L)]center dot H2O (1.H2O) [HL = 5-(hydroxymethyl)-8-methyl-3-thiol-7-azacoumarin]. This compound was characterized in solid state by IR spectroscopy and in solution by H-1 and C-13{H-1} NMR spectrometry. X-ray diffraction showed that the crystal consists of associated TlMe2(L) units and hydrogen bonded water molecules. The L- anion is bound to the metal mainly by a bridging S atom [Tl-S = 2.9458(18) angstrom; 2.9616(16) angstrom], although secondary interactions through O atoms (Tl-O: 2.861(5); 2.900(5) angstrom)] are also present. The longer Tl-O interaction and the hydrogen bonds of the water molecules give rise to a tridimensional polymeric structure. (C) 2012 Elsevier B.V. All rights reserved.

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Multi-element analysis of honey samples was carried out with the aim of developing a reliable method of tracing the origin of honey. Forty-two chemical elements were determined (Al, Cu, Pb, Zn, Mn, Cd, Tl, Co, Ni, Rb, Ba, Be, Bi, U, V, Fe, Pt, Pd, Te, Hf, Mo, Sn, Sb, P, La, Mg, I, Sm, Tb, Dy, Sd, Th, Pr, Nd, Tm, Yb, Lu, Gd, Ho, Er, Ce, Cr) by inductively coupled plasma mass spectrometry (ICP-MS). Then, three machine learning tools for classification and two for attribute selection were applied in order to prove that it is possible to use data mining tools to find the region where honey originated. Our results clearly demonstrate the potential of Support Vector Machine (SVM), Multilayer Perceptron (MLP) and Random Forest (RF) chemometric tools for honey origin identification. Moreover, the selection tools allowed a reduction from 42 trace element concentrations to only 5. (C) 2012 Elsevier Ltd. All rights reserved.

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In 1603, the Italian shoemaker Vincenzo Cascariolo found that a stone (baryte) from the outskirts of Bologna emitted light in the dark without any external excitation source. However, the calcination of the baryte was needed prior to this observation. The stone later named as the Bologna Stone was among the first luminescent materials and the first documented material to show persistent luminescence. The mechanism behind the persistent emission in this material has remained a mystery ever since. In this work, the Bologna Stone (BaS) was prepared from the natural baryte (Bologna, Italy) used by Cascariolo. Its properties, e. g. impurities (dopants) and their valences, luminescence, persistent luminescence and trap structure, were compared to those of the pure BaS materials doped with different (transition) metals (Cu, Ag, Pb) known to yield strong luminescence. The work was carried out by using different methods (XANES, TL, VUV-UV-vis luminescence, TGA-DTA, XPD). A plausible mechanism for the persistent luminescence from the Bologna Stone with Cu+ as the emitting species was constructed based on the results obtained. The puzzle of the Bologna Stone can thus be considered as resolved after some 400 years of studies.

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The structural distortions resulting from the size mismatch between the Eu2+ luminescent centre and the host Ba2+ cation as well as the electronic structure of BaAl2O4:Eu2+(,Dy3+) were studied using density functional theory (DFT) calculations and synchrotron radiation (SR) luminescence spectroscopy. The modified interionic distances as well as differences in the total energies indicate that Eu2+ prefers the smaller of the two possible Ba sites in the BaAl2O4 host. The calculated Eu2+ 4f(7) and 4f(6)5d(1) ground level energies confirm that the excited electrons can reach easily the conduction band for subsequent trapping. In addition to the green luminescence, a weak blue emission band was observed in BaAl2O4:Eu2+,Dy3+ probably due to the creation of a new Ba2+ site due to the effect of water exposure on the host. (C) 2012 Optical Society of America

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The following varieties of natural quartz, as the blue, the green, the red, the pink, the black, the sulphurous and the milky quartz, have been investigated concerning their thermoluminescence properties. For comparison sake natural colorless alpha quartz has been include. Since X-rays diffraction analysis has shown that all of them have the same crystal structure as the alpha quartz, it is expected that no great change in the TL property should be found, however, that was not the case. The TL peaks at 110, 175, 220, 325 and 375 degrees C observed in the alpha quartz are not found in all the varieties of quartz, for instance, the sulphurous quartz presented only 110 degrees and 245 degrees peaks, the pink one presented just 110, 220 and 375 degrees C peaks and so on. In respect to TL response as function of gamma ray dose a quite varied behavior has been observed and discussed. (C) 2012 Elsevier B.V. All rights reserved.

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Biological aspects of sailfin dory, Zenopsis conchifer, were studied from 839 individuals obtained from deep-sea commercial bottom trawling off southern Brazil at depths up to 526 m in 2002 and 2003. Samples included fish from 101 mm Lt and 15 g up to 640 mm Lt and 2,9 g. The sex-ratio was 50% at 150 mm Lt and between 300-350 mm Lt, with females outnumbering males in the remaining size classes. Reproductive activity seems to peak between July and August ( austral winter). Size at attainment of 50% maturity (Lt(50)) was 311 mm Lt in females. The mean length and maturity of the specimens increased with depth, suggesting that larger fish concentrate in deeper waters.

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Tb3+ doped CaZrO3 has been prepared by an easy solution combustion synthesis method. The combustion derived powder was investigated by X-ray diffraction, Fourier-transform infrared spectrometry and scanning electron microscopy techniques. A room temperature photoluminescence study showed that the phosphors can be efficiently excited by 251 nm light with a weak emission in the blue and orange region and a strong emission in green light region. CaZrO3:Tb3+ exhibits three thermoluminescence (TL) glow peaks at 126 degrees C, 200 degrees C and 480 degrees C. Electron Spin Resonance (ESR) studies were carried out to study the defect centres induced in the phosphor by gamma irradiation and also to identify the centres responsible for the TL peaks. The room temperature ESR spectrum of irradiated phosphor appears to be a superposition of two distinct centres. One of the centres (centre I) with principal g-value 2.0233 is identified as an O- ion. Centre II with an axial symmetric g-tensor with principal values g(parallel to) = 1.9986 and g(perpendicular to) = 2.0023 is assigned to an F+ centre (singly ionised oxygen vacancy). An additional defect centre is observed during thermal annealing experiments and this centre (assigned to F+ centre) seems to originate from an F centre (oxygen vacancy with two electrons). The F centre and also the F+ centre appear to correlate with the observed high temperature TL peak in CaZrO3:Tb3+ phosphor. (c) 2012 Elsevier B.V. All rights reserved.

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The persistent luminescence of CdSiO3:Tb3+ was investigated with photoluminescence, thermoluminescence (TL), synchrotron radiation X-ray absorption (XANES and EXAFS) and UV-VUV spectroscopies. Only the typical intraconfigurational 4f(8)-4f(8) transitions of the Tb3+ ion were observed with no traces of band emission in either the conventional UV excited or persistent luminescence spectra. The trap structure from TL with three traps from 0.65 to 0.85 eV is ideal for room-temperature persistent luminescence similar to, e.g., Sr2MgSi2O7:Eu2+,R3+. Despite the rather low band gap energy, 5.28 eV, the persistent luminescence from Tb3+ is produced only under UV irradiation due to the inauspicious position of the F-7(6) ground level deep in the band gap of CdSiO3. This confirms the role of electrons as the charge carriers in the mechanism of Tb3+ persistent luminescence. The XANES spectra indicated the presence of only the trivalent Tb3+ species, thus excluding the direct Tb3+ -> Tb-IV oxidation during the charging process of persistent luminescence. Eventually, a unique persistent luminescence mechanism for Tb3+ in CdSiO3 was constructed based on the comprehensive experimental data.

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O propósito deste estudo foi estimar a contribuição dos fatores genéticos e ambientais na variabilidade do desempenho interindividual na coordenação motora. A amostra foi constituída por 64 pares de gêmeos portugueses, com idades entre cinco e 14 anos. Avaliou-se o desempenho da coordenação através das quatro provas da bateria KTK: equilíbrio à retaguarda (ER); saltos monopedais (SM); transposição lateral (TL); saltos laterais (SL). Calculou-se o coeficiente de correlação intraclasse (t), sendo estimada a contribuição dos fatores genéticos (a²), ambientais comuns (c²) e únicos (e²). Os resultados mostram valores de t mais elevados entre gêmeos monozigóticos, sugerindo presença de fatores genéticos. Entretanto, estimativas de a² foram baixas, variando entre 15% (TL) e 41% (SM), enquanto para c² situaram-se entre 46% (SL) e 58% (TL), e para e² entre 11% (SM) e 28% (TL). Conclui-se que fatores ambientais são responsáveis pela maior parcela de influência na variabilidade do desempenho na coordenação motora.

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Energy transfer (ET) and heat generation processes in Yb3+/Ho3+-codoped low-silica calcium aluminosilicate glasses were investigated using thermal lens (TL) and photoluminescence measurements looking for the emission around 2.0 μm. Stepwise ET processes from Yb3+ to Ho3+, upon excitation at 0.976 μm, produced highly efficient emission in the mid-infrared range at around 2.0 μm, with high fluorescence quantum efficiency (η1 ∼ 0.85 and independent of Ho3+ concentration) and relatively very low thermal loading (<0.4) for concentration up to 1.5% of Ho2O3. An equation was deduced for the description of the TL results that provided the absolute value of η1 and the number of emitted photons at 2.0 μm per absorbed pump photon by the Yb3+ ions, the latter reaching 60% for the highest Ho3+ concentration. These results suggest that the studied codoped system would be a promising candidate for the construction of photonic devices, especially for medical applications.

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This thesis is focused on studies of substituted Hg-based superconducting copper oxides ((Hg1-xMx)Ba2Can-1CunO2n+2+δ). These compounds are promising objects of investigation, not only from a fundamental point of view but also because of their high values of superconducting transition temperature (Tc) and irreversibility field (Hirr). The first part of the thesis is devoted to optimization of the synthesis procedure for Hg-based cuprates. The influence of different parameters (T, t, p(Hg), p(O2)) on the synthesis of these compounds in sealed silica tubes was studied. Optimal conditions yielded samples containing up to 95% of HgBa2Ca2Cu3O8+δ (Hg-1223). The formation of solid solutions with the formula (Hg1-xCux)Ba2Ca2Cu3O8+δ (where x <= 0.5) was also established. Another technique was developed, using LiF as a flux, for synthesis of samples containing up to 90% of the HgBa2CaCu2O6+δ (Hg-1212) phase. The second part concerns synthesis and studies of oxyfluorides using Hg-1212 and Hg-1223 as starting materials together with XeF2 as a fluorinating agent. It was found that oxyfluorides of both phases have a parabolic dependence of Tc vs. a parameter as well as enhanced Tc values (ΔT ≈ 3-4 K) in comparison with optimally doped non-fluorinated analogues. The crystal structure of Hg-1223 oxyfluoride was studied by X-ray powder and neutron diffraction methods. It is suggested that chemical modification of the crystal structure leads to a decrease in Cu-O distance without noticeable change in Cu-O-Cu angle (in the (CuO2) layers), which may be the significant factors influencing this Tc increase. Hg-1223 oxyfluoride was also studied under high pressure for first time. It was found that this compound has a record-high Tc value (≈ 166 K) at P ≈ 23 GPa. The last part describes the investigation of substituted Hg-based superconductors in the series (Hg0.9M0.1)Ba2CuO4+δ {(Hg,M)-1201}, where M = Tl, Pb, W, Mo, Nb and V. A comprehensive study of these compounds by various methods (X-ray powder diffraction, EDX, IR-, EXAFS- and XANES -spectroscopy) indicated that the change of charge carrier doping level is a crucial factor determining the irreversibility line. (Hg0.9Mo0.1)Ba2CuO4+δ showed the most improved irreversibility line position among the (Hg,M)-1201 compounds studied in this series.

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[EN] Preliminary data of the length-weight relationship and reproduction of the bogue Boops boops off Gran Canaria (Canary Islands, Central-east Atlantic) are provided. Two thousand and twenty-one individuals of bogue, ranging from 4 to 34 cm TL, were obtained from purse seine commercial landing. Reproduction parameters as sex determination, duration of spawning season, size at first maturity and GSI variation along time were determinated based on macroscopic evaluation of gonads. The results obtained suggest that bogue is a total spawner, with a long spawning season extending from January to May. Size at first maturity was 16.7 and 17.9 cm TL for males and females, respectively. The length-weight relationship obtained showed a positive allometry in both sexes

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The present study aims at analyzing how dark humour as a cinematic genre travels cross-culturally through a specific mode of audiovisual translation, i.e. dubbing. In particular, it takes into consideration the processes involved in dubbing humour from English into Italian as observed in the English- and Italian-language versions of ten British and American dark comedies from the 1940s to the 2000s. In an attempt to identify some of the main mechanisms of the dark humour genre, the humorous content of the films was analyzed in terms of the elements on which specific scenes are based, mainly the non-verbal and verbal components. In the cases in which verbal elements were involved, i.e. the examples of verbally expressed humour, the analysis was concerned with whether they were adapted into Italian and to what effect. Quantification of the different kinds of dark humour revealed that in the sample of dark comedies verbal dark humour had a higher frequency (85.3%) than non-verbal dark humour (14.7%), which partially disconfirmed the first part of the research hypothesis. However, the significance of contextual elements in the conveying of dark humour, both in the form of Nsp VEH (54.31%) and V-V (V+VE) (21.68%), provided support for the hypothesis that, even when expressed verbally, dark humour is more closely linked to context-based rather than purely linguistic humour (4.9%). The second part of the analysis was concerned with an investigation of the strategies adopted for the translation of verbal dark humour elements from the SL (English) into the TL (Italian) through the filter of dubbing. Four translational strategies were identified as far as the rendering of verbal dark humour is concerned: i) complete omission; ii) weakening; iii) close rendering; and iv) increased effect. Complete omission was found to be the most common among these strategies, with 80.9% of dark humour examples being transposed in a way that kept the ST’s function substantially intact. Weakening of darkly humorous lines was applied in 12% of cases, whereas increased effect accounted for 4.6% and complete omission for 2.5%. The fact that for most examples of Nsp VEH (84.9%) and V-AC (V+VE) (91.4%) a close rendering effect was observed and that 12 out of 21 examples of V-AC (PL) (a combined 57%) were either omitted or weakened seemed to confirm, on the one hand, the complexity of the translation process required by cases of V-AC (PL) and V-AC (CS). On the other hand, as suggested in the second part of the research hypothesis, the data might be interpreted as indicating that lesser effort on the translator/adaptor’s part is involved in the adaptation of V-AC (Nsp VEH) and V-V (V+VE). The issue of the possible censorial intervention undergone by examples of verbal dark humour in the sample still remains unclear.