GNSS/INS组合系统模型精化及载波相位定位测姿

<正>INS不依赖外部信号源,抗干扰性强,以高采样率输出导航信息,但其误差随时间积累,GNSS导航结果长期稳定性较高,但存在采样率较低、信号易受干扰等缺点,将两者组合形成GNSS/INS系统可以最大程度发挥各自优势。提升硬件水平能改善导航定位性能,但成本巨大,短期内收效甚微。如何在现有硬件水平下完成各项导航定位任务是当前极为重要和迫切的问题。GNSS/INS组合系统采样率高、连续性好、输出参数全面,已渗透到国民经济发展和国防建设的各个领域,不     

一种正地闪触发过程观测和分析

利用2008年夏季在山东滨州获得的无线电窄带干涉仪及同步快慢电场资料,对发生于2008年6月29日的一次具有2次回击的正地闪进行了波形特征分析及定位处理。结果表明,正地闪预击穿过程起始于云中部负电荷区域,有持续时间长达163ms的预击穿过程,并在预击穿后期产生很多双极性脉冲。通过与负地闪的比较,发现云下部正电荷区的浓度对云中触发闪电的极性有一定的影响。正先导的触发和传输过程需要长时间的云内放电过程来提供能量,正流光传输是非阶梯型,结合同步观测的快电场三维定位结果的结合,得到正地闪首次先导速度约为4.1×105 m.s-1,首次回击的速度约为9×107 m.s-1,直窜先导的速度约为4.7×106 m.s-1,继后回击的速度约为9.6×107 m.s-1。正地闪的回击速度偏小,可能是由于干涉仪通道是二维的,且有一定的误差,还讨论了正地闪继后回击产生的原因是由于下部正电荷区很强,不同于一般的正地闪且只有1次回击过程。在该个例中还观测到正先导传输过程中的VHF辐射,这可能是由于雷暴过程下部正电荷区域很强。     

理学ZSX系列X荧光光谱仪中文软件开发

介绍了日本理学ZSX系列X荧光光谱仪的特点和新开发的中文版软件的功能。     

华南沿海4省区城市分类探析

采用城市就业人口的统计资料，运用城市经济基础分析、多变量聚类与统计分析相结合的方法，对东南沿海粤、闽、琼、桂4省区40个地级以上的城市进行综合职能分类、共分出5个大类9个亚类。分类结果对认识我国东南沿海主要城市的职能结构和职能特点有着重要的意义，也为本区域城市之间的比较研究提供了参照基础。     

陕西翠华山山崩其环境效应

陕西翠华山山崩主要由水湫池（天池）山崩体、甘湫池山崩体及大坪山崩体三部分组成，其中水湫池（天池）山崩体开发及研究较为成熟，是吸引游客的黄金地段，翠华山山崩的形成主要由内因素及外因因素所控制，其中内力因素包括翠华山花岗岩体背景因素和节理面理、断裂面理及变质地层面理等因素、外力因素包括陕西关中地震及暴雨等因素。翠华山山崩首次发现由三期山崩体组成，不同期次山崩有各自特色旅游环境，反映了出山崩自然现象亦有造福人类的积极方面。     

The impacts of urbanization on soil erosion in the Loess Plateau region

1 IntroductionThe Loess Plateau region covers an area of 62.4(104 km2 and lies in the center of northern China. Urbanization and economic development have been quickened in recent decades. Both the number of towns established and scale of cities have increased. Although the pace of urbanization has been accelerated, the eco-environmental control in urban areas still lags behind relatively. Moreover, the construction and development of cities damaged the already vulnerable eco-environment to …     

PRESENT-DAY KINEMATICS OF THE ORDOS BLOCK AND ITS SURROUNDING AREAS FROM GPS OBSERVATIONS

Located among the South China block, Tibetan plateau, Alxa block and Yinshan orogenic belt, the Ordos block is famous for its significant kinematic features with stable tectonics of its interior but frequent large earthquakes surrounding it. After the destruction of the North China Craton, the integrity, rotation movement and kinematic relations with its margins are hotly debated. With the accumulation of active tectonics data, and paleomagnetic and GPS observations, some kinematic models have emerged to describe rotation movement of the Ordos block since the 1970's, including clockwise rotation, anticlockwise rotation, clockwise-anticlockwise-alternate rotation, and sub-block rotation, etc. All of these models are not enough to reflect the whole movement of the Ordos block, because the data used are limited to local areas.
In this study, based on denser geophysical observations, such as GPS and SKS splitting data, we analyzed present-day crustal and mantle deformation characteristics in the Ordos block and its surrounding areas. GPS baselines, strain rates, and strain time series are calculated to describe the intrablock deformation and kinematic relationship between Ordos block and its margins. SKS observations are used to study the kinematic relationship between crust and deeper mantle and their dynamic mechanisms, combined with the absolute plate motion(APM)and kinematic vorticity parameters. Our results show that the Ordos block behaves rigidly and rotates anticlockwise relative to the stable Eurasia plate(Euler pole: (50.942±1.935)°N, (115.692±0.303)°E, (0.195±0.006)°/Ma). The block interior sees a weak deformation of~5 nano/a and a velocity difference of smaller than 2mm/a, which can be totally covered by the uncertainties of GPS data. Therefore, the Ordos block is moving as a whole without clear differential movement under the effective range of resolution of the available GPS datasets. Its western and eastern margins are characterized by two strong right-lateral shearing belts, where 0.2°~0.4°/Ma of rotation is measured by the GPS baseline pairs. However, its northern and southern margins are weakly deformed with left-lateral shearing, where only 0.1°/Ma of rotation is measured. Kinematics in the northeastern Tibetan plateau and western margin of the Ordos block can be described with vertical coherence model with strong coupling between the crust and deeper mantle induced by the strong extrusion of the Tibetan plateau. The consistency between SKS fast wave direction and absolute plate motion suggests the existence of mantle flow along the Qinling orogenic belt, which may extend to the interior of the Ordos block. SKS fast wave directions are consistent with the direction of the asthenosphere flow in Shanxi Rift and Taihang Mountains, indicating that the crustal deformation of these areas is controlled by subduction of the Pacific plate to North China. The week anisotropy on SKS in the interior of Ordos block is from fossil anisotropy in the craton interior. After comparing with the absolute plate motion direction and deformation model, we deem that anisotropy in the interior of Ordos block comes from anisotropy of fossils frozen in the lithosphere. In conclusion, the Ordos block is rotating anticlockwise relative to its margins, which may comes from positive movement of its margins driven by lithospheric extrusion or mantle flow beneath, and its self-rotation is slight. This study can provide useful information for discussion of kinematics between the Ordos block and its surrounding tectonic units.     

Discovery of Neoproterozoic Rocks in the Dunhuang Block: Clues to Correlation with Rodinia

正Objective Rodinia was a supercontinent that comprised nearly all the current existing continents/blocks on Earth to form a coherent large landmass during the Meso-Neoproterozoic. Thus, discovery of Meso-Neoproterozoic rocks in a certain Precambrian block can provide important clues for studying the assembly and break-up history of Rodinia. The Dunhuang Block, located at the southernmost part     

澜沧江流域云南段景观格局分析

流域作为一个特殊的地理生态环境区域,流域景观空间格局状况是进行流域环境资源管理的基础依据。针对澜沧江-湄公河国际河流上游云南段,基于遥感监测所获得的土地覆盖斑块信息,就该地区景观格局进行分析研究。初步结果表明：研究区内景观类型丰富,不同景观类型斑块大小的平均水平,以及斑块密度差异明显;山区早地斑块景观,作为人类驱动影响的直观外在表现,它对本流域山区景观格局具有主导作用。     

珠三角岭南文化与主要外省人原籍文化的比较

比较分析珠三角地区岭南文化与主要外省人原籍文化之间的共同性和差异性特征。研究表明:珠三角六大主要外省人文化与岭南文化具有共同的文化基石和文字表达方式,在文化传统和文化特征上也有一定程度的共同性;受地理环境、历史发展等因素的影响,中原文化具有浓厚的北方旱作农耕文化的特色,长江流域荆楚文化具有显著的稻作农耕文化的特色,而岭南文化则具有明显的南方海洋文化的特色;具体在饮食文化、服饰文化等物质形态文化领域也表现出明显的差异性。正确认识各种文化之间的异同点,能有助于实现文化的趋同和融合,发展有利于现代化的文化要素,逐步革除不利于现代化的文化要素,在文化互动中实现文化的现代化和文化大省的建设。