Laboratory kinetics of C₂H radical reactions with ethane, propane, and n-butane at T = 96-296 K: implications for Titan     

James E. Murphy  Stephen R. Leone 《Icarus》2003,163(1):175-181

The kinetics of the reactions of C₂H radical with ethane (k₁), propane (k₂), and n-butane (k₃) are studied over the temperature range of T = 96-296 K with a pulsed Laval nozzle apparatus that utilizes a pulsed laser photolysis-chemiluminescence technique. The C₂H decay profiles in the presence of both the alkane reactant and O₂ are monitored by the CH(A²Δ) chemiluminescence tracer method. The results, together with available literature data, yield the following Arrhenius expressions: k₁(T) = (0.51 ± 0.06) × 10⁻¹⁰ exp[(−76 ± 30)K/T] cm³ molecule⁻¹ s⁻¹ (T = 96-800 K), k₂(T) = (0.98 ± 0.32) × 10⁻¹⁰exp[(−71 ± 60)K/T] cm³ molecule⁻¹ s⁻¹ (T = 96-361 K), and k₃(T) = (1.23 ± 0.26) × 10⁻¹⁰ cm³ molecule⁻¹ s⁻¹ (T = 96-297 K). At T = 296 K, k₁ is measured as a function of total pressure and has little or no pressure dependence. The results from this work support a direct hydrogen abstraction mechanism for the title reactions. Implications to the atmospheric chemistry of Titan are discussed.  相似文献   

The effects of topographically-controlled thermal tides in the martian upper atmosphere as seen by the MGS accelerometer     

Paul Withers  S.W Bougher 《Icarus》2003,164(1):14-32

Mars Global Surveyor accelerometer observations of the martian upper atmosphere revealed large variations in density with longitude during northern hemisphere spring at altitudes of 130-160 km, all latitudes, and mid-afternoon local solar times (LSTs). This zonal structure is due to tides from the surface. The zonal structure is stable on timescales of weeks, decays with increasing altitude above 130 km, and is dominated by wave-3 (average amplitude 22% of mean density) and wave-2 (18%) harmonics. The phases of these harmonics are constant with both altitude and latitude, though their amplitudes change significantly with latitude. Near the South Pole, the phase of the wave-2 harmonic changes by 90° with a change of half a martian solar day while the wave-3 phase stays constant, suggesting diurnal and semidiurnal behaviour, respectively. We use a simple application of classical tidal theory to identify the dominant tidal modes and obtain results consistent with those of General Circulation Models. Our method is less rigorous, but simpler, than the General Circulation Models and hence complements them. Topography has a strong influence on the zonal structure.  相似文献   

Double–double radio galaxies: remnants of merged supermassive binary black holes     

F. K. Liu  Xue-Bing Wu  S. L. Cao 《Monthly notices of the Royal Astronomical Society》2003,340(2):411-416

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南山站对陆地—5号资源卫星的可观测范围及以该站为中心的覆盖区域     

桑思武 《天文研究与技术》1996,(4)

本文简要介绍了陆地系列地球资源卫星的轨道特征，并以陆地—５号资源卫星为例，根据南山站的座标计算出该站对陆地—５号资源卫星的可观测范围及以该站为中心的卫星的覆盖区域。  相似文献   

GDJ人卫目视观测数据采集和处理系统的研制     

何妙婵 《天文研究与技术》1996,(1)

本文介绍了ＧＤＪ跟踪打印经纬仪在人造卫星的观测中如何应用计算机对多圈卫星的目视观测资料进行实时采集、处理等工作过程的原理和方法。  相似文献   

Self-regulated black hole accretion, the M–σ relation and the growth of bulges in galaxies     

Mitchell C. Begelman †  Biman B. Nath ‡ 《Monthly notices of the Royal Astronomical Society》2005,361(4):1387-1392

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观驾山—黑岛一带信息量法找金研究     

简文星  吕贻峰  秦松贤  刘吉平 《国土资源》1996,(2)

本文以成矿地质模型为依据，对观驾山—黑山岛一带的化探、物探、遥感及地质等信息变量进行了详细的分析，选取了１０个信息变量２４个标志状态；在此基础上，运用信息量法对研究区内４５８个单元的信息量值进行计算，并由此确定了研究范围内的成矿远景区。事实表明，研究区信息量成矿预测是非常有效的  相似文献   

Revised masses of dust and gas of SCUBA Local Universe Survey far-infrared bright galaxies based on a recent CO survey     

Ernest Seaquist  Lihong Yao  Loretta Dunne  Heather Cameron 《Monthly notices of the Royal Astronomical Society》2004,349(4):1428-1434

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小卫星数据的变化监测能力分析     

李静  党福星  李志忠 《测绘科学》2009,34(3)

为了促进小卫星数据在地质灾害监测中的应用与推广,本文以监测采矿图斑变化为目标,通过对北京地区的2006年和2007年两期北京一号小卫星4m全色影像采用正射校正、配准和迭加对比的方法发现变化信息。结合1∶50 000影像图、野外调查和测量,确定变化图斑的边界、变化原因和规模,并对小卫星全色图像的变化监测能力进行分析和总结。本文通过对小卫星4m全色影像数据的分析,基本上可以概括出其变化监测能力。  相似文献   

基于SAR干涉点目标分析技术的城市地表形变监测   总被引：1，自引：0，他引：1  

张永红  张继贤  龚文瑜  LU Z 《测绘学报》2009,38(6)

通过深入研究干涉点目标的相位模型,提出基于空间搜索的邻近点目标干涉相位差解缠方法,用以计算点目标的地形残差和线性形变,以及分离点目标大气延迟相位和非线性形变相位的时空域滤波方法,解决干涉点目标分析中的关键问题.最后,以苏州地区地表沉降监测为应用试验,利用形成的SAR干涉点目标形变信息提取技术,获取苏州市区1992-2002年间的地表沉降信息.研究结果与已有文献记录保持比较好的一致性,证明SAR干涉点目标技术完全可以发展成为应用于城市地表形变监测的实用化技术.

Abstract：

Interferometric point target analysis (IPTA) is one of the latest developments in radar interferometric processing. It is achieved by analysis of the interferometric phases of some individual point targets, which are discrete and present temporarily stable backscattering characteristics, in long temporal series of interferometric SAR images. This paper analyzes the interferometric phase model of point targets, and then addresses two key issues within IPTA process. Firstly, a spatial searching method is proposed to unwrap the interferometric phase difference between two neighboring point targets. The height residual error and linear deformation rate of each point target can then be calculated, when a global reference point with known height correction and deformation history is chosen. Secondly, a spatial-temporal filtering scheme is proposed to further separate the atmosphere phase and nonlinear deformation phase from the residual interferometric phase. Finally, an experiment of the developed IPTA methodology is conducted over Suzhou urban area. Totally 38 ERS-1/2 SAR scenes are analyzed, and the deformation information over 3 546 point targets in the time span of 1992-2002 are generated. The IPTA-derivecl deformation shows very good agreement with the published result, which demonstrates that the IPTA technique can be developed into an operational tool to map the ground subsidence over urban area.  相似文献