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Using synthetic spectra derived from an updated model atmosphere together with a continuum model that includes contributions from haze, cloud and ground, we have re-analyzed the recently published (Geballe et al., 2003, Astrophys. J. 583, L39-L42) high-resolution 3 μm spectrum of Titan which contains newly-detected bands of HCN (in emission) and C2H2 and CH3D (in absorption), in addition to previously detected bands of CH4. In the 3.10-3.54 μm interval the analysis yields strong evidence for the existence of a cloud deck or optically thick haze layer at about the 10 mbar (∼ 100 km) level. The haze must extend well above this altitude in order to mask the strong CH4 lines at 3.20-3.50 μm. These cloud and haze components must be transparent at 2.87-2.92 μm, where analysis of the CH3D spectrum demonstrates that Titan's surface is glimpsed through a second cloud deck at about the 100 mbar (∼ 50 km) level. Through a combination of areal distribution and optical depth this cloud deck has an effective transmittance of ∼ 20%. The spectral shape of Titan's continuum indicates that the higher altitude cloud and haze particles responsible for suppressing the CH4 absorptions have a largely organic make-up. The rotational temperature of the HCN ranges from 140 to 180 K, indicating that the HCN emission occurs over a wide range of altitudes. This emission, remodeled using an improved collisional deactivation rate, implies mesospheric mixing ratio curves that are consistent with previously predictions. The stratospheric and mesospheric C2H2 mixing ratios are ∼10−5, considerably less than previous model predictions (Yung et al., 1984), but approximately consistent with recent observational results. Upper limits to mixing ratios of HC3N and C4H2 are derived from non-detections of those species near 3.0 μm. 相似文献
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Li D Dong M Shim WJ Hong SH Oh JR Yim UH Jeung JH Kanan N Kim ES Cho SR 《Marine pollution bulletin》2005,51(8-12):966-974
In order to investigate spatial and temporal distribution of organic pollutants in the Saemangeum Bay, organophosphorus pesticides (10), alkylphenols (8), chlorophenols (2), bisphenol A were analyzed from the surface seawater taken in 2002–2003. Most of the analytes were not detected in all stations except nonylphenol and S-benzyl-O,O-di-isopropyl phosphorothioate (IBP). Concentrations of nonylphenol and IBP ranged from ND to 298 ng/l and from ND to 1840 ng/l, respectively. The high levels of nonylphenol and IBP were found in the estuary areas of Mangyeong and Dongjin River. The levels of nonylphenol and IBP in surface seawater varied through seasons and the high levels of nonylphenol and IBP were in summer season (August). Based on real time monitoring of IBP and on correlation between concentrations of target compounds and contents of salinity in seawater, physical mixing and diffusion of seawater were found to be the major factors that affect the spatial distribution of IBP and nonylphenol in the Saemangeum Bay environment. 相似文献
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Element geochemistry and cleaning potential of the No. 11 coal seam from Antaibao mining district 总被引:1,自引:0,他引:1
WANG Wenfeng QIN Yong SONG Dangyu SANG Shuxun JIANG Bo ZHU Yanming & FU Xuehai . College of Resources & Geosciences China University of Mining Technology Xuzhou China . State Key Laboratory of Coal Combustion Huazhong University of Science Technology Wuhan China 《中国科学D辑(英文版)》2005,48(12):2142-2154
It has aroused great attention that the mobilization of potential toxic substance during coal mining, pro- cessing and using has serious negative influence on environment. Clearly, the coal cleaning can be prop-erly applied to removing hazardous elements or re-ducing their concentrations prior to combustion, which also is considered as an economical and effective technique in minimizing some of these problems[1]. Unfortunately, there are fairly few studies on the parti-tioning behavior of trac… 相似文献
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Infrared spectra of Jupiter's atmosphere were obtained with the infrared spectrometer (IRS) on the 1.5-m telescope at the Cerro Tololo Inter-American Observatory (CTIO) during the first 2 days of the impacts of the fragments of Comet Shoemaker–Levy 9 (1993e). We monitored 3.51 ± 0.17 μm radiation from the impact areas, undisturbed areas, and auroral regions of Jupiter after the A and E impacts. The strong emission of a portion of the P-branch of the ν3band of CH4was detected on the A impact area 4 hr after the impact. H+3emissions are found to be decreased at the A and E impact sites after 4 hr and 10 hr 50 min of the impacts, respectively, compared with undisturbed areas at the same latitude. The temperatures of the southern H+3aurora were normal within the first several hours following the A and E impacts. 相似文献
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Dong-Hwan Hwang Sang Heon Oh Sang Jeong Lee Chansik Park Chris Rizos 《GPS Solutions》2005,9(4):294-311
Due to their complementary features of GPS and INS, the GPS/INS integrated navigation system is increasingly being used for
a variety of commercial and military applications. An attitude determination GPS (ADGPS) receiver, with multiple antennas,
can be more effectively integrated with a low-cost IMU since the receiver gives not only position and velocity data but also
attitude data. This paper proposes a low-cost attitude determination GPS/INS integrated navigation system. The proposed navigation
system comprises an ADGPS receiver, a navigation computer unit (NCU), and a low-cost commercial MEMS IMU. The navigation software
includes a fault detection and isolation (FDI) algorithm for integrity. In order to evaluate the performance of the proposed
navigation system, two flight tests have been performed using a small aircraft. The first flight test confirmed the fundamental
operation of the proposed navigation system and the effectiveness of the FDI algorithm. The second flight test evaluated the
performance of the proposed navigation system and demonstrated the benefit of GPS attitude information in a high dynamic environment.
The flight test results show that the proposed ADGPS/INS integrated navigation unit gives reliable navigation performance
even when anomalous GPS data is provided and gives better navigation performance than a conventional GPS/INS unit. 相似文献
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受地质、地貌、水文气象条件及人类活动的影响,丹巴县泥石流、滑坡、崩塌及潜在不稳定斜坡地质灾害呈现分布广、成灾快、危害大等特点。本文分析了主要控制和影响因素,提出预防、避让和工程治理方面的防治对策。 相似文献