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161.
We present absorption cross sections of propane (C3H8) at temperatures from 145 K to 297 K in the 690–1550 cm−1 region. Pure and N2-broadened spectra were measured at pressures from 3 Torr to 742 Torr using a Bruker IFS125 FT-IR spectrometer at JPL. The gas absorption cell, developed at Connecticut College, was cooled by a closed-cycle helium refrigerator. The cross sections were measured and compiled for individual spectra recorded at various experimental conditions covering the planetary atmosphere and Titan. In addition to the cross sections, a propane pseudoline list with a frequency grid of 0.005 cm−1, was fitted to the 34 laboratory spectra. Line intensities and lower state energies were retrieved for each line, assuming a constant width. Validation tests showed that the pseudoline list reproduces discrete absorption features and continuum, the latter contributed by numerous weak and hot band features, in most of the observed spectra within 3%. Based on the pseudoline list, the total intensity in the 690–1550 cm−1 region was determined to be 52.93 (±3%) × 10−19 cm−1/(molecule cm−2) at 296 K; this value is within 3% of the average from four earlier studies. Finally, the merit of the pseudoline approach is addressed for heavy polyatomic molecules in support of spectroscopic observation of atmospheres of Titan and other planets. The cold cross sections will be submitted to the HITRAN database (hitran.harvard.edu), and the list of C3H8 pseudolines will be available from a MK-IV website of JPL (http://mark4sun.jpl.nasa.gov/data/spec/Pseudo). 相似文献
162.
H. S. Edgell 《Australian Journal of Earth Sciences》2013,60(2):235-261
The palaeontology, correlation and sedimentation of the Proterozoic sequence in the Hamersley Range, Western Australia, are discussed. Fossil calcareous algal growths, such as stromatolites and onkolites are described, as well as possible medusoid impressions. These indicate shallow water accumulation of the sediments and provide evidence of the extensive existence of plant and animal life in the Late Precambrian of Western Australia. Distinctive stromatolites are shown to characterize various levels in the Proterozoic succession. A descending sequence of stromatolite assemblages is proposed denoted by:
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Collenia frequens—Conophyton cf. inclinatum
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Collenia australasica—C. undosa
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C. cf. kona—C. brockmani
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C. sp. aff. multiflabella.
163.
名义上无水矿物(nominally anhydrous minerals,NAMs)中以点缺陷形式存在的结构水,因其对于矿物物理化学性质的显著影响而受到越来越广泛的关注。橄榄石是上地幔中含量最丰富的矿物,水在橄榄石中的存在形式、扩散机制和速率对上地幔的流变学和电导性质有着重要的影响。因此,对于橄榄石中H的结合机制及其扩散机制和速率的了解有助于理解地球深部的水循环,也有助于构建上地幔流变结构以及解释电导测量结果。本文总结了近几十年来学界对于H在橄榄石中存在的缺陷类型与OH红外光谱吸收峰之间的对应关系,以及H在矿物晶格中的扩散机制、扩散速率等重要问题的研究成果,并探讨了现有研究中依然存在的问题。 相似文献
164.
J.N. Walsh P.A. Taylor A. Buckley T.W. Darling J. Schreuer M.A. Carpenter 《Physics of the Earth and Planetary Interiors》2008,167(1-2):110-117
Values of bulk modulus (K), shear modulus (G) and mechanical quality factor (Q) have been determined for polycrystalline samples across the CaTiO3 (CST0)–SrTiO3 (CST100) solid solution by resonant ultrasound spectroscopy. Because of similarities with low frequency elastic and anelastic anomalies due to twin wall motion reported in previous studies, a working hypothesis is developed in which dissipation processes are interpreted in terms of twin wall displacements. At high temperatures in CST50 the stability field of the I4/mcm structure is marked by the disappearance of all resonance peaks (superattenuation). This is attributed to anelastic domain wall sliding. At room temperature the I4/mcm phase of CST70 and CST80 has values of G which are lower than those of cubic or orthorhombic phases, and a concomitant drop in Q is interpreted as implying that the domain wall pinning process reported elsewhere to occur below 400–450 K is only partial. A similar drop in G and Q was found in CST95 below the transition at 238 K. The I4/mcm ↔ Pbcm transition in CST70 at 230 K is marked by an abrupt increase in Q, suggesting that mobile twins in crystals with the I4/mcm structure become effectively immobile in antiferroelectric crystals with the Pbcm structure. The I4/mcm ↔ Pnma transition in CST50 is marked by a similarly abrupt increase in Q, consistent with twin walls becoming effectively immobile also in crystals with the Pnma structure. A fall in Q below 800 K in CST0, however, could imply that a degree of twin wall mobility might develop in Pnma crystals if the tetragonal spontaneous strain departs significantly from zero. The remarkable attenuation behaviour of crystals with the I4/mcm structure at the relatively low stress conditions which apply during resonances of a parallelepiped with edge dimensions of 2–4 mm, is consistent with the view that a characteristic signature for tetragonal CaSiO3 in the Earth's lower mantle should be a marked attenuation of seismic waves. 相似文献
165.
微量金化学光谱法标准系列配制及活性炭处理的改进 总被引:2,自引:0,他引:2
对微量金化学光谱法中活性炭自理及标准系列配制的方法进行了探索,改进了微量金化学光谱法活性炭处理及标准系列配制。将该法配制的标准系列应用于微量金化光谱测定,提高了分析结果的准确度。用标准试样分析及原子吸收(AAS)法验证,结果与标准值及AAS法相符。 相似文献
166.
E. Schmidbauer Th. Kunzmann Th. Fehr R. Hochleitner 《Physics and Chemistry of Minerals》2000,27(5):347-356
Electrical resistivity and 57Fe Mössbauer spectra are reported for three calcic amphiboles with different Fe concentrations. AC measurements (20?Hz–1?MHz) were performed, applying impedance spectroscopy between 100 and 785?°C in an N2 gas atmosphere. It was found that up to three semiconducting charge transport processes can be distinguished, which in part changed slightly when several runs were carried out to higher temperatures. The extrapolated DC resistivity is much smaller for an amphibole with high Fe content than for the two with lower Fe concentrations. The derived activation energies are between ~0.48 and ~1.06?eV. For temperatures ≤600?°C the results are compatible with a charge transport mechanism due to electron hopping between Fe2+ and Fe3+. Above 600?°C, dehydrogenation and/or beginning amphibole decomposition obviously alter the conduction mechanism. From Mössbauer spectra it was established that in all amphibole samples Fe2+ and Fe3+ are simultaneously present. Mössbauer parameters were derived by fitting the observed spectra to models taking the occupation of various M sites into account. 相似文献
167.
The polarized single-crystal Raman spectra of synthetic H2O-containing alkali-free beryl were recorded at room and low temperatures, and the polarized single-crystal IR spectra at
room temperature. The H2O molecule in the channel cavities is characterized by a Raman-active symmetric stretching vibration (ν1) at 3607 cm−1 and an IR-active asymmetric stretch (ν3) at 3700 cm−1 at room temperature. At low temperatures this ν3 mode is observed in the Raman. Weak ν1 and ν3 modes of a second type of H2O are also observed in the Raman spectra but only at 5 K. The H⋯·H vector of the most abundant type of H2O is parallel to the channel axis of beryl along [0 0 0 1]. The components of the polarizability tensor of the ν1 mode of H2O are similar to, but not exactly the same as, those of a free H2O molecule. The Raman measurements indicate that the H2O molecule is rotationally disordered around [0 0 0 1]. External translation and librational modes of H2O could be observed as overtones with the internal H2O-stretching modes. In the case of the librational motions, normal modes could also be observed directly in the Raman spectra
at ∼200 cm−1. The energies of the translational modes can be determined from an analysis of the overtones and are about 9 cm−1 in energy (i.e., Tz). The energies of the librational modes are about 210 cm−1 for Rx and 190 cm−1 for Ry.
Received: 8 April 1999 / Accepted: 5 April 2000 相似文献
168.
K. Mizumura Y. Kumagait H. Tsutsui T. Nishimoto T. Yamamoto 《Environmental Geology》2000,39(10):1147-1154
X-ray fluorescent spectroscope analysis easily finds ratios of geochemical elements in soil. Applying the method of ratio
matching to measured ratios, the classification of geological layers, and the flow directions of groundwater can be determined.
This method is applied to three hill slopes in Japan and the results are in good agreement with the observations and measurements
of soil cores obtained by drilling. The classification of geological layers is found to be quantitatively connected with the
rates of organic matter in soil cores.
Received: 5 February 1999 · Accepted: 7 September 1999 相似文献
169.
PLS-ANN分析血浆自体荧光光谱的二阶导数光谱识别胃癌 总被引:1,自引:0,他引:1
探讨偏最小二乘法结合神经网络法(简称PLS-ANN)分析血浆自体荧光光谱的二阶导数光谱识别胃癌的优势,对20例胃癌病人和23例健康人血浆进行以405nm为激发光的自体荧光光谱检测,采用PLS-ANN法分别对血浆自体荧光光谱和二阶导数光谱进行判别分析。PLS-ANN分析血浆的自体荧光光谱法诊断胃癌的灵敏度为75%,特异度为83%,准确率为79%,PLS-ANN分析血浆的二阶导数光谱法诊断胃癌的灵敏度为90%,特异度为96%,准确率为93%。结果表明PLS-ANN分析血浆的二阶导数光谱法识别胃癌,优于PLS-ANN分析血浆的自体荧光光谱法,有望成为快速识别胃癌的较理想方法。 相似文献
170.