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31.
AM Johnston CM Scrimgeour MO Henry LL Handley 《Rapid communications in mass spectrometry : RCM》1999,13(14):1531-1534
The conversion of nitrate (NO(3)(-)) to 1-phenylazo-2-naphthol (Sudan-1) has been examined as a method for natural abundance measurement of delta(15)N of NO(3)(-). The reaction results in dilution of NO(3)(-)-N with only one reagent-derived N and the product is readily concentrated from dilute samples by reverse phase chromatography. There is systematic isotopic fractionation during the reaction, but this can be allowed for by analysing known NO(3)(-) standards along with each sample set. Sudan-1 prepared from surface water samples containing approximately 50 &mgr;g NO(3)(-)-N can be analysed by automated continuous flow isotope ratio mass spectrometry with a precision of 0.2 per thousand (one standard deviation) and the accuracy is not affected by interference from other nitrogenous species in the sample or reagents. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
32.
Rubens R Santos Jr Alexandrina Sartori Deison S Lima Patrícia RM Souza Arlete AM Coelho-Castelo Vania LD Bonato Célio L Silva 《Journal of immune based therapies and vaccines》2009,7(1):4-12
Background
Our group previously demonstrated that a DNA plasmid encoding the mycobacterial 65-kDa heat shock protein (DNA-HSP65) displayed prophylactic and therapeutic effect in a mice model for tuberculosis. This protection was attributed to induction of a strong cellular immunity against HSP65. As specific immunity to HSP60 family has been detected in arthritis, multiple sclerosis and diabetes, the vaccination procedure with DNA-HSP65 could induce a cross-reactive immune response that could trigger or worsen these autoimmune diseases. 相似文献33.
34.
Inelastic scattering induces dephasing in mesoscopic systems. An analysis of previous models to simulate inelastic scattering
in such systems is presented and a relatively new model based on wave attenuation is introduced. The problem of Aharonov-Bohm
(AB) oscillations in conductance of a mesoscopic ring is studied. We show that the conductance is symmetric under flux reversal
and the visibility of AB oscillations decays to zero as a function of the incoherence parameter, signaling dephasing. Further
the wave attenuation model is applied to a fundamental problem in quantum mechanics, that of the conditional (reflection/transmission)
times spent in a given region of space by a quantum particle before scattering off from that region. 相似文献
35.
M. E. Akopyan S. S. Lukashov S. A. Poretsky A. M. Pravilov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(1):116-124
The luminescence excitation spectra and the luminescence spectra of the I2 + Rg (Rg = He, Ar, Xe; p
Rg = 2–20 Torr) mixtures measured at room temperature by the method of double optical resonance in the spectral range corresponding
to the population of the I2(f0
g
+, v
f
= 8.9) levels and in its vicinity are analyzed in this work. The experimental data and their interpretation, according to
which these spectra can be explained by the energy transfer in the intermediate I2(B0
u
+) and final I2(f0
g
+) states of the free iodine molecule rather than by the optical population, luminescence, and predissociation of the ion-pair
RgI2(IP) complexes, are discussed. It is shown that these data can be explained only with account taken of the optical population
of the RgI2(IP) complexes.
Original Russian Text ? M.E. Akopyan, S.S. Lukashov, S.A. Poretsky, A.M. Pravilov, 2009, published in Zhurnal Fizicheskoi
Khimii, 2009, Vol. 83, No. 1, pp. 132–141. 相似文献
36.
K.D. Setzer W. Zyrnicki A.M. Pravilov E.H. Fink K.K. Das H.-P. Liebermann R.J. Buenker 《Journal of Molecular Spectroscopy》2003,217(1):127-141
Gas phase emission spectra of the hitherto unknown free radical PbLi have been measured in the NIR range with a Fourier-transform spectrometer. The emissions were observed from a fast flow system in which lead vapor in argon carrier gas was passed through a microwave discharge and mixed with lithium vapor in an observation tube. Five electronic transitions have been found in the wavenumber range 3800-10 000 cm−1. Bands from two excited states to the ground state were measured at high spectral resolution such that rotational analyses could be performed and accurate molecular parameters derived. In order to aid in the analysis of the experimental data, a series of relativistic configuration interaction calculations has been carried out to obtain potential curves for the low-lying states of PbLi and also electric dipole transition moments connecting them. As in the lighter molecules of this group, CLi and SiLi, the ground state of PbLi is found to be 3/2) with a spin splitting of about 2000 cm−1. The first excited state is (A 1/2), and two observed band systems are assigned to the transitions A→X1 and A→X2. Two more excited states, (B 3/2) and C 1/2, are identified from the observed spectra with the help of the computed data, and their spectroscopic constants are determined. In contrast to PbH and PbF, the ab initio results indicate a very complicated low-energy electronic structure for the PbLi radical, with 19 bound electronic states calculated to lie below 3 eV. 相似文献
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Much is known about the connection between the growth and decayof subharmonic functions. The results indicate that there isa general principle: asubharmonic function cannot decay toofast relative to its growth.Three theorems are provedwhich, together with work previously published elsewhere, givea fairly complete account of how this principle works out fora subharmonic function having extremal decay along a ray. 1991Mathematics Subject Classification: 30D20, 31A05. 相似文献
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