924 resultados para SPECTRAL-LINES


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The fast sequential multi-element determination of Ca, Mg, K, Cu, Fe, Mn and Zn in plant tissues by high-resolution continuum source flame atomic absorption spectrometry is proposed. For this, the main lines for Cu (324.754 nm), Fe (248.327 nm), Mn (279.482 nm) and Zn (213.857 nm) were selected, and the secondary lines for Ca (239.856 nm), Mg (202.582 nm) and K (404.414 nm) were evaluated. The side pixel registration approach was studied to reduce sensitivity and extend the linear working range for Mg by measuring at wings (202.576 nm; 202.577 nm; 202.578 nm; 202.580 nm: 202.585 nm; 202.586 nm: 202.587 nm; 202.588 nm) of the secondary line. The interference caused by NO bands on Zn at 213.857 nm was removed using the least-squares background correction. Using the main lines for Cu, Fe, Mn and Zn, secondary lines for Ca and K, and line wing at 202.588 nm for Mg, and 5 mL min(-1) sample flow-rate, calibration curves in the 0.1-0.5 mg L-1 Cu, 0.5-4.0 mg L-1 Fe, 0.5-4.0 mg L-1 Mn, 0.2-1.0 mg L-1 Zn, 10.0-100.0 mg L-1 Ca, 5.0-40.0 mg L-1 Mg and 50.0-250.0 mg L-1 K ranges were consistently obtained. Accuracy and precision were evaluated after analysis of five plant standard reference materials. Results were in agreement at a 95% confidence level (paired t-test) with certified values. The proposed method was applied to digests of sugar-cane leaves and results were close to those obtained by line-source flame atomic absorption spectrometry. Recoveries of Ca, Mg, K, Cu, Fe, Mn and Zn in the 89-103%, 84-107%, 87-103%, 85-105%, 92-106%, 91-114%, 96-114% intervals, respectively, were obtained. The limits of detection were 0.6 mg L-1 Ca, 0.4 mg L-1 Mg, 0.4 mg L-1 K, 7.7 mu g L-1 Cu, 7.7 mu g L-1 Fe, 1.5 mu g L-1 Mn and 5.9 mu g L-1 Zn. (C) 2009 Elsevier B.V. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This work describes the synthesis, IR and (13)C CPMAS NMR spectroscopic as well the thermal characterization of the new dicarboxylate complexes [Pd(2)(ox)(2)(4,4'-bipy)]n (1), [Pd(2)(ox)(2)(bpe)](n) (2) and [Pd(2)(ox)(2)(pz)](n) (3) {ox = oxalate, bipy = 4,4'-bipyridine, bpe = 1,2-bis(4-pyridyl)ethane, pz = pyrazine}. TG experiments reveal that compounds 1-3 undergo thermal decomposition in three steps. Metal palladium was the final product of the thermal decompositions, which was identified by X-ray powder diffraction.

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The synthesis and thermal behavior of the new [Pd(fum)(bipy)] (n) center dot 2nH(2)O (1), [Pd(fum)(bpe)] (n) center dot nH(2)O (2) and [Pd(fum)(pz)] (n) center dot 3nH(2)O (3) {bipy = 4,4'-bipyridine, bpe = 1,2-bis(4-pyridyl)ethene and pz = pyrazine} fumarate complexes are described in this work as well their characterization by IR and (13)C CPMAS NMR spectroscopies. TG curves showed that the compounds released organic ligands and lattice water molecules in the temperature range of 46-491 A degrees C. In all the cases, metallic palladium was identified as the final residue.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Análise espectral de flores utilizada por aves nectarívoras em áreas urbanas. O objetivo deste trabalho foi estabelecer a característica espectral das flores produtoras de néctar visitadas por nectarívoros em áreas urbanas. Este estudo foi desenvolvido na região central do município de Taubaté, no nordeste do Estado de São Paulo. As áreas amostradas incluíram espaços verdes, tais como praças e parques e a vegetação das ruas e avenidas. Foram registradas 12 espécies de plantas utilizadas por cinco espécies de aves nectarívoras. As espécies de flores mais visitadas foram aquelas que refletiram em comprimento de onda longos (>600 nm). Foi discutida a capacidade de detecção das aves em função de visão tetracromática das aves nectarívoras e da conspicuidade das flores em ambientes urbanos. Finalmente, foi abordado o problema da escassez de plantas atrativas para aves nectarívoras nas áreas verdes urbanas e a necessidade de se aumentar a quantidade dessas espécies de plantas para incrementar a biodiversidade em regiões urbanas.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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A biologia de Bemisia tabaci biótipo B (Genn.) foi avaliada em genótipos de feijoeiro (Phaseolus vulgaris L.) que contêm arcelina em suas sementes. Foi também realizada análise bioquímica de proteínas, em sementes e em folhas dos genótipos de feijoeiro, a fim de verificar se haveria traços de arcelina nas folhas dos materiais a serem avaliados. Os testes foram conduzidos em condições de casa de vegetação, nas épocas das águas e da seca, em dois anos consecutivos, com os seguintes genótipos: ARC 3s, ARC 5s (genótipos selvagens portadores de arcelina); ARC 1, ARC 2, ARC 3, ARC 4 (linhagens quase-isogênicas portadoras de arcelina - Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA)), Porrillo 70, Bolinha e IAPAR MD 808 (genótipos sem arcelina). Os genótipos selvagens, ARC 3s e ARC 5s, apresentaram altos níveis de antibiose, com ênfase para o ARC 5s (as ninfas tiveram alta mortalidade, em torno de 90%). O prolongamento do ciclo de desenvolvimento dos insetos provenientes do genótipo ARC 5s podem sugerir uma resistência do tipo antibiose e/ou não-preferência para alimentação. A resistência dos genótipos selvagens não está relacionada com a presença de arcelina nas sementes, já que nenhum traço dessa proteína foi encontrado nas folhas destes.

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We investigated the IR absorption spectrum of (CH3OH)-C-13 around the frequency of the 10R(20) CO2 laser line. We found two absorption lines which can be excited by 10R(20) and studied the FIR laser emissions excited by this pump line using a waveguide CO2 laser of 300 MHz tunability: We report two new FIR laser lines of large offset, not previously observed due to their weakness and closeness to other stronger lines. We measured the frequencies of five FIR laser lines for the first time by an accurate heterodyne technique and present the complete assignments of the IR-FIR laser systems relative to this pump line. Furthermore we present new frequency values for two FIR laser lines whose frequencies had been previously wrongly measured. Copyright (C) 1997 Elsevier B.V. Ltd.

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We report 18 new laser lines from (CH3OH)-C-13 generated in an optically pumped far-infrared laser; the laser lines are in the range of 54.2-420 mu m and are all characterized in wavelength, polarization relative to the pumping CO2 radiation, and pump offset relative to the CO2 center frequency, the frequencies of seven of these new lines along with 10 previously reported lines were measured by an accurate heterodyne technique, mixing them in a metal-insulator-metal (MIM) point contact diode, with another laser line of known frequency.

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Synthesis, spectroscopic characterization and thermal behavior of pyrazolate-bridged palladium complexes [Pd(mu-Pz)(2)](n) (1), [Pd(mu-mPz)(2)](n) (2), [Pd(mu-dmPz)(2)](n) (3), [Pd(mu-IPz)(2)](n) (4) {pyrazolate (Pz(-)), 4-methylpyrazolate (mPz(-)), 3,5-dimethylpyrazolate (dmPz(-)), 4-iodopyrazolate (IPz(-))} have been described in this work. The exobidentate coordination mode of pyrazolato ligands in 1-4 was inferred on basis of IR spectroscopic evidences. TG investigations indicated that the introduction of substituents at the 4 position in the pyrazolyl moiety into coordination polymers do not affect significantly their thermal stability, whereas at the 3 and 5 position reduced the stability of the main chain. Metal palladium was the final product of the thermal decompositions, which was identified by X-ray powder diffraction.

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Fourier transform and IR optoacoustic absorption data of (CD3OH)-C-13 were used to search for new FIR laser lines. We have used a waveguide CO2 laser of 300 MHz tunability as the optical pumping source. We report the observation and characterization of 13 new lines. Three of these lines are associated with absorbing transitions appertaining to the weak (CD3)-C-13 asymmetric bending mode.