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1.
Lieve A. De Bock Boris Treiger Ludo Van der Auwera René E. Van Grieken 《Mikrochimica acta》1998,128(3-4):191-200
To reveal useful environmental information which is contained in large analytical data sets, an approach, based on the successive application of hierarchical cluster analysis and factor analysis, is proposed. Estimation criteria to determine the most suitable number of clusters and/or factors, are discussed and the interpretation of the cluster and factor analyses results is performed using visual techniques. The data sets were obtained by scanning electron microscope-energy-dispersive X-ray analysis of individual North Sea aerosol particles. 相似文献
2.
de Farias RF de Souza JM de Melo JV Airoldi C 《Journal of colloid and interface science》1999,212(1):123-129
The effects exhibited by adsorbed conducting polyaniline on the redox process on a molybdenum oxide surface were studied. Thermogravimetric results indicate a 4% polyaniline deposition. Cyclic voltammograms of the adsorbed polymer on MoO3 show that polyaniline exerts remarkable effects on the molybdenum blue oxidation-reduction process, with oxidation and reduction potentials of 0.33 and 0.18 V, respectively. This effect strongly enhances the electrode response, and can be used as an important tool in qualitative and/or quantitative determinations of molybdenum in solution as well as in any substrate. Copyright 1999 Academic Press. 相似文献
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F. LattanziC. di Lauro M. HermanJ.Vander Auwera 《Journal of Molecular Spectroscopy》2002,216(2):308-314
A detailed investigation of the high-resolution infrared spectrum of ethane revealed the occurrence of features belonging to the hot perpendicular system (ν4+ν8)−ν4 between 1400 and 1510 cm−1. Transition lines of the subbranches with K″ΔK from −7 to 4, exhibiting torsional splittings of several tenths of a cm−1, were observed and measured in this region. The observed line splittings are strongly influenced by the interaction between the ν4+ν8 and 2ν4+ν12 states and change with the values of K″ΔK, depending on the zero-order energy separation of the interacting levels. We found by numerical extrapolation that splittings still occur far from resonance, showing that the intrinsic torsional splittings of the combining states ν4+ν8 and ν4 are quite different. We determined the intrinsic torsional splitting of ν4+ν8 to be less than 0.083 cm−1, compared with 0.236 cm−1 estimated for the ν4 state. This result is in agreement with the expected effects of torsional Coriolis and head-tail coupling and is consistent with previous observations on vibrationally degenerate states of ethane-like molecules. 相似文献
5.
Vara Prasad JV 《Organic letters》2000,2(8):1069-1072
[formula: see text] A simple synthesis of heterocyclic thiosulfonates containing indole, indoline, benzoimidazole, and quinoxaline rings is described. The synthesis of these thiosulfonates involves the preparation of the appropriately substituted thiols followed by sulfonylation to give thiosulfonates. The corresponding thiols were prepared in a simple and efficient manner by using a thiocyanation reaction either prior to heterocycle ring formation or after heterocycle ring formation. These thiosulfonates were coupled successfully to the 5,6-dihydropyran-2-one ring to give products that showed excellent HIV protease activity. 相似文献
6.
Vander Auwera J 《Journal of Molecular Spectroscopy》2000,201(1):143-150
We measured absolute line intensities in two bands of (12)C(2)H(2) near 7.5 μm, namely the nu(4) + nu(5)(Sigma(+)(u))-0(Sigma(+)(g)) and nu(4) + nu(5)(Delta(u))-0(Sigma(+)(g)) bands, using Fourier transform spectroscopy with an accuracy estimated to be better than 2%. Using theoretical predictions from Watson [J. K. G. Watson, J. Mol. Spectrosc. 188, 78 (1998)], the observation of the forbidden nu(4) + nu(5)(Delta(u))-0(Sigma(+)(g)) band and the Herman-Wallis behavior exhibited by its rotational lines were studied quantitatively in terms of two types of interactions affecting the levels involved by the band: l-type resonance and Coriolis interaction. In the case of the nu(4) + nu(5)(Sigma(+)(u))-0(Sigma(+)(g)) band, the influence of l-type resonance is also confirmed. We also attributed the intensity asymmetry observed between the R and P branches of that latter band to a Coriolis interaction with l = 1 levels. We did not observe the nu(4) + nu(5)(Sigma(-)(u))-0(Sigma(+)(g)) band, consisting only of a Q branch, in agreement with Watson's prediction. Copyright 2000 Academic Press. 相似文献
7.
D. Hurtmans M. Herman J. Vander Auwera 《Journal of Quantitative Spectroscopy & Radiative Transfer》1993,50(6):595-602
We have measured the integrated band intensities of the ν9 and ν11 bands of N2O4 which are observed around 1757 and 1261 cm-1, respectively. By varying temperature and pressure, we have obtained: Sband(ν9) = 9.60(130), 9.10(24), 8.80(66) and Sband(ν11)= 5.93(64), 5.70(21) and 5.33(46) (in 10-17 cm/molecule) at 293.15 (60), 277.25 (60) and 261.65 (60) K, respectively. 相似文献
8.
Absolute line intensities of 13C16O2 were retrieved from high-resolution Fourier transform spectra recorded in the region 3090-3920 cm−1. The uncertainty of the line intensity determination is estimated to be between 3 and 5% for the strong lines. The global fittings of the observed line intensities within the framework of the effective operators approach have been performed, reaching the experimental accuracy. A comparison of newly measured line intensities with those found in the HITRAN database is presented. 相似文献
9.
N. Jacquinet-Husson N.A. Scott L. Crépeau V. Capelle A. Coustenis N. Poulet-Crovisier M. Birk C. Camy-Peyret K. Chance C. Clerbaux P.F. Coheur L. Daumont G. Di Lonardo A. Goldman M. Hess D. Jacquemart P. Köpke S. Massie V. Nemtchinov D. Newnham V.I. Perevalov L. Régalia-Jarlot A. Rublev L. Schult S.A. Tashkun R.A. Toth J. Vander Auwera G. Wagner 《Journal of Quantitative Spectroscopy & Radiative Transfer》2008,109(6):1043-1059
The development of Gestion et Etude des Informations Spectroscopiques Atmosphériques (GEISA: Management and Study of Spectroscopic Information) was started over three decades at Laboratoire de Météorologie Dynamique (LMD) in France. GEISA is a computer accessible spectroscopic database, designed to facilitate accurate forward radiative transfer calculations using a line-by-line and layer-by-layer approach. More than 350 users have been registered for on-line use of the GEISA facilities. The current 2003 edition of GEISA (GEISA-03) is a system comprising three independent sub-databases devoted respectively to: line transition parameters, infrared and ultraviolet/visible absorption cross-sections, microphysical and optical properties of atmospheric aerosols.Currently, GEISA is involved in activities related to the assessment of the capabilities of IASI (Infrared Atmospheric Sounding Interferometer on board of the METOP European satellite) through the GEISA/IASI database derived from GEISA.The GEISA-03 content is presented, placing emphasis on molecular species of interest for Earth and planetary atmosphere studies, with details on the updated 2008 archive underway. A critical assessment on the needs, in terms of molecular parameters archive, related with recent satellite astrophysical missions is made. Detailed information on free on-line GEISA and GEISA/IASI access is given at http://ara.lmd.polytechnique.fr and http://ether.ipsl.jussieu.fr. 相似文献
10.
Absolute line intensities in the nu(6) and nu(8) interacting bands of trans-HCOOH, observed near 1105.4 and 1033.5 cm(-1), respectively, and the dissociation constant of the formic acid dimer (HCOOH)(2) have been measured using Fourier transform spectroscopy at a resolution of 0.002 cm(-1). Eleven spectra of formic acid, at 296.0(5) K and pressures ranging from 14.28(25) to 314.0(24) Pa, have been recorded between 600 and 1900 cm(-1) with an absorption path length of 19.7(2) cm. 437 integrated absorption coefficients have been measured for 72 lines in the nu(6) band. Analysis of the pressure dependence yielded the dissociation constant of the formic acid dimer, K(p)=361(45) Pa, and the absolute intensity of the 72 lines of HCOOH. The accuracy of these results was carefully estimated. The absolute intensities of four lines of the weak nu(8) band were also measured. Using an appropriate theory, the integrated intensity of the nu(6) and nu(8) bands was determined to be 3.47 x 10(-17) and 4.68 x 10(-19) cm(-1)(molecule cm(-2)) respectively, at 296 K. Both the dissociation constant and integrated intensities were compared to earlier measurements. 相似文献