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61.
本文计算了一批OH/IR星的绝对K星等Mk,对OH/IR星的Mk和距离d作了讨论。发现当K较亮时,Mk为一常数;当K较暗时,Mk较离散且呈现一定的变化趋势。本文还拟合得到了一个由K星等求距离的经验公式,并由此公式计算了一批OH/IR星的距离。最后,对所得结果进行了解释和讨论。 相似文献
62.
Maik Pertermann Alan G. Whittington Anne M. Hofmeister Frank J. Spera John Zayak 《Contributions to Mineralogy and Petrology》2008,155(6):689-702
Thermal diffusivity (D) was measured using laser-flash analysis from oriented single-crystal low-sanidine (K0.92Na0.08Al0.99Fe3+
0.005Si2.95O8), and three glasses near KAlSi3O8. Viscosity measurements of the three supercooled liquids, in the range 106.8 to 1012.3 Pa s, confirm near-Arrhenian behavior, varying subtly with composition. For crystal and glass, D decreases with T, approaching a constant near 1,000 K: D
sat ∼ 0.65 ± 0.3 mm2 s−1 for bulk crystal and ∼0.53 ± 0.03 mm2 s−1 for the glass. A rapid decrease near 1,400 K is consistent with crossing the glass transition. Melt behavior is approximated
by D = 0.475 ± 0.01 mm2 s−1. Thermal conductivity (k
lat) of glass, calculated using previous heat capacity (C
P) and new density data, increases with T because C
P strongly increases with T. For melt, k
lat reaches a plateau near 1.45 W m−1 K−1, and is always below k
lat of the crystal. Melting of potassium feldspars impedes heat transport, providing positive thermal feedback that may promote
further melting in continental crust. 相似文献
63.
Subtle variations of frequencies in the infrared (IR) absorption spectra of beryl have been predicted based on the coordination
between extra-framework cations and water molecules in two orientations (referred to as type I and type II) trapped within
the channel. In this study, the polarized IR spectra of hydrated synthetic beryl and natural beryl were measured to clarify
the relationships between the frequencies of the absorption bands and the coordination states of type II water. Na+ was assumed to be the predominant cation coordinated to type II water in our samples, as determined by chemical analyses.
These measurements revealed a clear quantitative linear relationship in absorbance between bands at 3,602 and 1,619 and at
3,589 and 1,631 cm−1. On the basis of experimental and theoretical studies, we assigned these pairs of bands to the ν1 and ν2 modes of doubly coordinated type II H2O and to singly coordinated type II H2O, respectively. These assignments were supported by IR measurements of annealed natural beryl. We also conducted dehydration
studies of natural beryl, in which two observed dehydration peaks, at 600 and 750°C, suggested the dehydration of type I and
type II water, respectively. 相似文献
64.
Young-Chan NOH Byung-Ju SOHN Yoonjae KIM Sangwon JOO William BELL Roger SAUNDERS 《大气科学进展》2017,34(11):1265-1281
A new set of Infrared Atmospheric Sounding Interferometer(IASI) channels was re-selected from 314 EUMETSAT channels.In selecting channels,we calculated the impact of the individually added channel on the improvement in the analysis outputs from a one-dimensional variational analysis(1D-Var) for the Unified Model(UM) data assimilation system at the Met Office,using the channel score index(CSI) as a figure of merit.Then,200 channels were selected in order by counting each individual channel's CSI contribution.Compared with the operationally used 183 channels for the UM at the Met Office,the new set shares 149 channels,while the other 51 channels are new.Also examined is the selection from the entropy reduction method with the same 1D-Var approach.Results suggest that channel selection can be made in a more objective fashion using the proposed CSI method.This is because the most important channels can be selected across the whole IASI observation spectrum.In the experimental trial runs using the UM global assimilation system,the new channels had an overall neutral impact in terms of improvement in forecasts,as compared with results from the operational channels.However,upper-tropospheric moist biases shown in the control run with operational channels were significantly reduced in the experimental trial with the newly selected channels.The reduction of moist biases was mainly due to the additional water vapor channels,which are sensitive to the upper-tropospheric water vapor. 相似文献
65.
We report a study on the broadband ultraviolet photolysis of methane-water ice mixtures, at low methane concentrations and temperatures relevant to the icy satellites of the outer Solar System. The photochemistry of these mixtures is dominated by the action of hydroxyl radicals on methane and the resulting products. This implies that, given sufficient exposure time, the methane will eventually be completely oxidized to carbon dioxide. The presence of methane inhibits the formation of hydrogen peroxide by serving as a trap for hydroxyl radicals. The distribution of photochemical products is broadly similar to that previously conducted using ion and electron sources, with some differences possibly attributable to the difference in radiation source. The results are applicable to a variety of icy bodies in the Solar System. On Enceladus, where methane mixed with water is measured in the plumes, methane in the surface ices is subject to oxidation and will eventually be converted to CO2. The CH stretch feature detected in the VIMS spectra of the Enceladus surface ice suggests that methane is currently being supplied to the surface ice, likely from re-condensation of the plume gas. 相似文献
66.
Detecting Aerosols over Land from Satellites by Measuring Far IR Radiation from the Earth-Atmospheric System
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In this study, a special method is proposed for detecting aerosols over land by analyzing satellite-measured far IR radiation at three channels, 8.7, 11.5, and 12.5 um. Sensitivity tests revealed that the behavioral features of radiative brightness temperatures (BTs) at these three channels with increasing optical depth are different among different types of aerosols. Analyzing how BTs and their differences, xBT (BT11.5-BT12.5) and yBT (BT8.7-BT11.5), behave with varying optical depth can help to qualitatively distinguish among aerosols and semi-quantitatively estimate their optical thicknesses. In addition, the authors found that the vertical density profile of aerosols has little impact on this method. 相似文献
67.
We study radiation-induced amorphization of crystalline ice, analyzing the results of three decades of experiments with a variety of projectiles, irradiation energy, and ice temperature, finding a similar trend of increasing resistance of amorphization with temperature and inconsistencies in results from different laboratories. We discuss the temperature dependence of amorphization in terms of the ‘thermal spike’ model. We then discuss the common use of the 1.65 μm infrared absorption band of water as a measure of degree of crystallinity, an increasingly common procedure to analyze remote sensing data of astronomical icy bodies. The discussion is based on new, high quality near-infrared reflectance absorption spectra measured between 1.4 and 2.2 μm for amorphous and crystalline ices irradiated with 225 keV protons at 80 K. We found that, after irradiation with 1015 protons cm−2, crystalline ice films thinner than the ion range become fully amorphous, and that the infrared absorption spectra show no significant changes upon further irradiation. The complete amorphization suggests that crystalline ice observed in the outer Solar System, including trans-neptunian objects, may results from heat from internal sources or from the impact of icy meteorites or comets. 相似文献
68.
利用NOAA卫星AVHRR的3个红外通道的探测资料推算的海面温度场,分析了海面温度对热带气旋路径的影响,其结果是在127段热带气旋路径中有100段路径偏向暖海水区。 相似文献
69.
新疆博尔塔拉盆地含油碎屑岩的初步研究 总被引:1,自引:0,他引:1
在新疆博尔塔拉中亚型地洼盆地第三系地洼构造层中首次发现油浸碎屑岩,经气相色谱、红外光谱及有机质谱的初步分析.确认存在丰富的有机质,主要成分为饱和烷烃。表明地层中有生油和聚积的过程,这将为在该地洼区进一步开展找油(气)工作提供方向。 相似文献
70.
J. L.?Pérez-RodríguezEmail author J.?Poyato M. C.?Jiménez de Haro L. A.?Pérez-Maqueda A.?Lerf 《Physics and Chemistry of Minerals》2004,31(7):415-420
The investigation of the NH3 loss in the NH4+-vermiculite (Santa Olalla) by thermogravimetry, evolved gas analysis, chemical analysis, X-ray diffraction and IR spectroscopy is reported here. The mass loss during heating takes place in two steps at about 650 and 825 °C. Additionally, the releases of H2O and NH3 occurs simultaneously. The experimental results indicate that the protons remaining in the interlayer space after NH3 removal trigger the H2O release. X-ray diffraction shows that during the decomposition of NH4+-vermiculite there are two domains with different interlayer spaces at ~9 and ~10 Å. As the decomposition proceeds, the intensity of the 9 Å peak increases at the expense of the second one. The change in the IR-stretching modes of the structural OH groups during heating indicates that the OH groups surrounded by 3Mg2+ or 2Mg2+Fe2+ are released at lower temperatures than those with environments like 2Mg2+Fe3+, 2Mg2+Al3+ or more complex ones. 相似文献