High resolution infrared spectroscopy of the sun and the earth's atmosphere from space

The atmospheric trace molecule spectroscopy experiment (ATMOS) was designed to obtain high-resolution absorption spectra of the atmosphere from earth orbit, from which the vertical distributions of a large number of minor and trace molecular constituents could be retrieved. The ATMOS instrument is an FFT spectrometer covering the 600 to 5000 cm^–1 frequency range and uses a double-passed, tilt-compensated optical configuration, with the two retroreflectors moving reciprocally. The scan time of 2 s gives spectra with an unapodized resolution of 0.01 cm^–1, spaced 4 km apart, vertically.The first flight of ATMOS was made in April, 1985, as part of the Shuttle Spacelab-3 science payload. A total of 19 sunrise and sunset occultations were observed, which resulted in the acquisition of more than 1000 atmospheric spectra with an equal number of solar only scans. The spectra show absorptions of some 40 different atmospheric constituents, some of which are discernable at altitudes well into the thermosphère (i.e., up to about 150 km). The high signal/noise ratio and repeatability of the spectra have enabled a wealth of new atmospheric data to be retrieved, including the first positive identifications of such key reservoir species as COF₂, HNO₄, and N₂O₅, simultaneous vertical distributions of the minor gases from 5 to 140 km, the entire odd-nitrogen family in the stratosphere, and most of the halogen source gases with their corresponding reservoir and sink species. Measurements of the frequencies of large numbers of spectral lines has yielded Doppler shifts from which zonal winds, having a precision of the order of 2 m/s, have been retrieved throughout the stratosphere and mésosphère.     

Ti2: accurate determination of the dissociation energy from matrix resonance Raman spectra and chemical interaction with noble gases

UV-visible and resonance Raman spectra of Ti(2) isolated in Ar, Kr, and Xe matrices at temperatures of 10 K were measured by using the 514 nm line of an Ar ion laser. The data show that the Ti(2) molecule interacts strongly with Xe, leading to a significant weakening of the Ti[bond]Ti bond strength. The f(Ti[bond]Ti) force constant decreases in the series Ar>Kr>Xe, from 232.8 Nm(-1) in Ar and 225.5 Nm(-1) in Kr to 199.7 Nm(-1) in Xe. Additional experiments in an Ar matrix containing 2 % of Xe indicate the formation of a molecule of the formula Ti(2)Xe. Our spectra for Ti(2) in an Ar matrix give evidence for several previously not observed members of the Stokes progression. The sum of experimental data allows for an improved estimation of the dissociation energy on the basis of a LeRoy-Bernstein-Lam analysis. A dissociation energy of 1.18 eV was derived from this analysis. The UV-visible data give evidence of the vibrational levels of an excited state of Ti(2).     

K促进的Fe/椰壳炭催化剂对甲烷氮气常压合成氨性能的影响

采用等体积浸渍法制备了一系列催化剂用于甲烷氮气常压合成氨反应.对Si O2、γ-Al2O3、煤质柱状炭、椰壳活性炭为载体的Fe基催化剂的活性评价结果显示椰壳炭载体最优;通过对Zr、Ce、K等多种助剂的筛选,发现K促进的Fe基催化剂氨生成速率最高.利用XRD、SEM、BET等手段对载体和催化剂进行表征,结果表明椰壳炭具有规则孔道且孔容增大,催化剂还原后有新晶相KFe O2生成.最后在固定床微分反应器中,考察了常压合成氨催化剂的负载顺序及最优工况.结果表明,在常压700℃、VCH4/VN2=2/1、空速为2 800 m L/h时,催化剂3%K-5%Fe/椰壳炭的氨生成速率最高可达1.04×10-6mol·g-1·s-1,是现有文献值的83.5倍,将具有深远的工业应用前景.     

Determination of selected trace elements in marine biota samples with the application of fast temperature programs and solid sampling continuous source high resolution atomic absorption spectroscopy: method validation

Analytical procedure for the determination of As, Cd, Cu, Ni, Co and Cr in marine biota samples using solid sampling high-resolution continuum source atomic absorption spectrometry (HR CS AAS) and accelerated fast temperature programmes has been developed. Calibration technique based on the use of solid certified reference materials similar to the nature of the analysed sample and statistics of regression analysis were applied. A validation approach in line with the requirements of ISO 17025 standard and Eurachem guidelines was followed. Accordingly, blanks, selectivity, calibration, linearity, working range, trueness, repeatability and reproducibility, limits of detection and quantification and expanded uncertainty for all investigated elements were assessed. The major contributors to the combined uncertainty of the analyte mass fractions were found to be the homogeneity of the samples and the microbalance precision. Traceability to the SI system of units of the obtained with the proposed analytical procedure results was also demonstrated. The potential of the proposed analytical procedure based on solid sampling HR CS AAS technique was demonstrated by direct analysis of marine reference biota samples. Overall, the use of solid sampling HR CS AAS permits obtaining significant advantages for the determination of selected trace elements in marine biota samples, such as straightforward calibration, a high sample throughput, sufficient precision, a suitable limit of detection and reduced risk of analyte loss and contamination.     

Synthesis of polyesters as binders for deinkable inks. VI. Structural analysis of the copolyesterification between o-phthalic anhydride,oleic acid,and trimethylolpropane in bulk at 160°C by high resolution 13C- and 1H nuclear magnetic resonance (13C- and 1H-NMR)

A detailed structural analysis of the copolyesterification in bulk without any external catalyst at 160°C between o-phthalic anhydride (P), oleic acid (O), and trimethylolpropane (T) with a mol ratio ([ COOH]/[ OH]) = 0.70 has been carried out by high resolution ¹³C nuclear magnetic resonance (¹³C-NMR) (DMSO-d₆ and CDCl₃ solutions), ¹H nuclear magnetic resonance (¹H-NMR) (CDCl₃ solution), and by volumetry. The use of CDCl₃ as NMR solvent has allow us to identify several signals that have been assigned to trimethylolpropane monoesters with different esterification degrees in the o-phthalate residue. Identically, we have detected signals assignable to monoesters at the chain ends in structures with different chain lengths. These monoesterified structures have been also confirmed by analyzing samples modified by the diazomethane addition. These modified samples have been also used to determine free acid groups as their methoxylic derivatives by ¹H-NMR in CDCl₃ solution. We have not observed any detectable signs of gelation nor products produced by secondary reactions. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3409–3429, 1997     

Synthesis of polyesters as binders for deinkable inks. I. Structural analysis of the polyesterification between o-phthalic anhydride and neopentyl glycol in bulk at 200°C by high resolution 13C nuclear magnetic resonance (13C-NMR)

Analysis of the polyesterification in bulk without any external catalyst at 200°C of o-phthalic anhydride with neopentyl glycol (2,2-dimethyl-1,3-propanediol) with a mole ratio ([(SINGLE BOND) COOH]/[ (SINGLE BOND) OH]) = 0.7 has been carried out by high resolution ¹³C nuclear magnetic resonance (¹³C-NMR). Polyesters can be analyzed by ¹³C-NMR spectra because of the fact that both o-phthalic acid (o-phthalic anhydride) and neopentyl glycol carbons are sensitive to sequence effects. Spin-lattice relaxation times T₁, of quaternary, tertiary and secondary carbons in different structures are in the 0.1–6.5 s range depending on the neighboring residue effects in the polymer chain. © 1996 John Wiley & Sons, Inc.