机载激光雷达在山区高速公路勘测中的应用

应用于军事技术的IMU/DGPS技术近几年发展迅速,通过某山区高速公路项目勘测中,对IMU/DGPS技术的运用实践,阐述该项技术的基本原理,对其在我国公路领域的应用进行展望.     

无人机视频数据定位处理系统的设计与实现

以无人机获取的视频数据为基础,利用VC++6.0编程软件,设计开发一套无人机视频数据定位处理系统.该系统的主要功能包括:利用无人机平台定位数据、姿念测量数据和视频图像数据,结合待测区域的数字高程模型(DEM)或数字表面模型(DSM),对实时传输或回放视频中地晰运动物体进行目标定位,并将视频图像实时纠正为正射影像.     

基于空间自相关BP神经网络的遥感影像亚像元定位

亚像元定位技术是一种获取地物在混合像元中分布信息的有效方法.提出一种基于空间自相关函数的遥感影像BP神经网络亚像元定位方法,与传统的BP神经网路亚像元定位方法相比,该方法利用空间自相关函数Moran's I 在亚像素级上对定位结果进行约束,其结果更符合空间相关性假设理论.试验结果表明,该方法优于传统BP神经网络亚像元定...     

Modeling of co- and post-seismic surface deformation and gravity changes of M W 6.9 Yushu,Qinghai,earthquake

Based on the elastic dislocation theory, multilayered crustal model, and rupture model obtained by seismic waveform inversion, we calculated the coand post-seismic surface deformation and gravity changes caused by the Yushu M W 6.9 earthquake occurred on April 14, 2010. The observed GPS velocity field and gravity field in Yushu areas are disturbed by the coand post-seismic effects induced by Yushu earthquake, thus the theoretical coand post-seismic deformation and gravity changes will provide important modi...     

用强震记录检验深厚土层小应变下一维等效线性化土层地震反应

本文以强震记录为基础,通过土层地震反应计算得到了地表加速度与加速度反应谱,对比研究了由强震记录得到的地表加速度以及由地表加速度得到的与土层地震反应相同阻尼下的加速度反应谱.结果表明:在高频段与中频段,用一维等效线性化计算得到的土层地震反应加速度值与反应谱值比地表实测得到的加速度记录值与加速度反应谱值偏低;但在低频段,计...     

Manifestation of planetary wave-type oscillations in variations in the critical frequencies of the ionospheric <Emphasis Type="Italic">F</Emphasis>2 layer in the Asian region

Results of studies of the wave structure of the critical frequencies of the ionospheric F2 layer with periods of planetary waves for two Asian stations—Irkutsk and Wuhan (China)—are presented. Estimates of the appearance frequency, amplitudes, and the lifetime of oscillations with periods typical of planetary waves (2–25 days) are obtained. It is shown that these characteristics depend on the season and place of observation. The appearance of joint periodicities in the critical frequencies at both stations, as well as in the planetary index of geomagnetic activity Ap, is noted.     

江淮流域典型旱涝年夏季大气水汽输送和收支特征分析

利用NCEP/NCAR再分析资料对1994年和1998年这两个典型旱涝年江淮流域水汽输送和收支状况等进行了诊断分析。结果表明：干旱年该地区主要为南北向水汽输送所控制,而洪涝年江淮流域上空有较强的东西向输送,干旱年5—8月由西、南边界的水汽输入明显比洪涝年少,这是造成该地区旱涝的重要原因,因而在未来的江淮流域旱涝预测中要特别重视西、南边界的水汽输送。     

Partitioning of Nb and Ta between rutile and felsic melt and the fractionation of Nb/Ta during partial melting of hydrous metabasalt

In order to fully assess the role of rutile in fractionation of Nb/Ta during partial melting of hydrous metabasalt, we have measured rutile - felsic melt partition coefficients (D values) for Nb and Ta with tonalitic to trondhjemitic compositions at 1.5-3.5 GPa, 900-1350 °C and ∼5.0-20 wt% H₂O. D_Nb, D_Ta and D_Nb/D_Ta range from 17 ± 1 to 246 ± 13, 34 ± 2 to 232 ± 25 and 0.51 ± 0.04 to 1.06 ± 0.13, respectively. For the compositions investigated, melt composition appears to have no observable effect on the partitioning; the effect of pressure is also slight; whereas temperature and H₂O have marked effects. D_Nb, D_Ta and D_Nb/D_Ta increase with decreasing temperature and H₂O content, showing a reversal of D_Nb/D_Ta from <1.0 to >1.0. Using the data that approached equilibrium and obeyed Henry’s law, expressions describing the dependences of D_Nb, D_Ta and D_Nb/D_Ta on temperature, pressure and melt H₂O content were obtained:

(1)     

A new application of headspace single-drop microextraction technique for compound specific carbon isotopic determination of gasoline range hydrocarbons

In this study, headspace single-drop microextraction (HS-SDME) coupled with gas chromatography-isotope ratio mass spectrometry (GC-IRMS), was employed to determine compound specific carbon isotopic values (δ¹³C) of gasoline range hydrocarbons. The reproducibility of the method was found to be satisfactory. By comparison with the δ¹³C values of the twelve target compounds determined using direct injection of their n-C₁₆ solution, no obvious isotopic fractionation was observed during the HS-SDME procedures. Some parameters that could affect the carbon isotopic fractionation, such as ionic strength of working solutions and inlet split ratio, were examined. The results also suggest that these factors had no significant effect on the carbon isotopic determination of gasoline range hydrocarbons. The application of HS-SDME to a crude oil sample proved that this method could be a promising tool for the determination of carbon isotopic values of gasoline range hydrocarbons in oils or aqueous samples.     

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