HHT方法在受城市轨道交通干扰地电场观测数据中的应用

较为详细地介绍了希尔伯特-黄变换方法,并将该方法中的经验模态分解功能和边际谱功能应用于受城市轨道交通干扰较大的北京市通州区西集镇地电场台站的观测资料中,对城市轨道交通在地电场观测中的影响进行了分析研究.结果表明,在地电场观测台站受到轨道交通干扰时,布极方位与轨道方向一致的测道所记录的数据受到的影响最大;利用经验模态分解...     

断层构造对地震地电阻率异常的影响

分析了典型震例,研究了断层构造对地电阻率异常空间分布的影响;应用弹-塑性二维有限元方法,模拟汁算了含断层的地质体中介质应变的空间不均匀分布.换算为视电阻率变化,解释了震前地电阻率异常空间不均匀分布的现象.研究表明,震源区周围地电阻率中期,短临异常空间不均匀分布的根本原因足断层构造以及不同震源机制引起的地下介质变形的不均...     

数字地图的研究进展和应用新方向

数字地图是现代地图学发展的重要标志.目前,国内外已出现以数字地图为核心的地图数据库、印刷地图、电子地图、移动式地图、网络地图等多种现代地图的开发和应用模式.本文分析和阐述数字地图理论、方法和技术方面的新进展,以及新的应用方向.首先,作者阐述了在数字地图新理论方面的研究进展,并在此基础上提出了数字地图体系结构框架;其次,...     

基于网格的精准农业数据库及示范应用——以黑龙江农场双山基地为例

精准农业是指按照田间每一操作单元的具体条件,精细准确地调整各项土壤和作物管理措施,最大限度地优化使用各项农业投入(如化肥、农药、水、种子和其他方面的投入量),以获取最高产量和最大经济效益,同时减少化学物质使用,保护农业生态环境,保护土地等自然资源.本文从精准农业对数据的要求入手,提出以格网为单元的精准农业数据库的设计思...     

The most compact bright radio-loud AGN—I. A new target sample selected for the space VLBI

We investigated the archival ground-based VLBI images of the extragalactic radio sources included in both the Wilkinson Microwave Anisotropy Probe (WMAP) and the Planck catalogues, and selected 49 bright and compact sources as potential targets for space Very Long Baseline Interferometry (VLBI) observations at mm wavelengths. These sources have a flat radio continuum spectrum between 33 and 94 GHz. They are identified as core-dominated active galactic nuclei (AGN), located at declinations above ?40^°, and have never been observed with ground-based VLBI at 86 GHz. The radio properties of the 49 new sources are presented. We compare this new sample with similar samples of compact AGN available from earlier studies. The new candidates, together with the existing bright compact AGN sample identified from 86-GHz ground-based VLBI imaging surveys, form a catalogue of more than 160 AGN. These could be primary targets for mm-VLBI observations on the ground, as well as for future mm-wavelength space VLBI missions such as the project with two satellites currently under study in China.     

Enhancement of the inertial navigation system for the Morpheusautonomous underwater vehicles

This paper presents the design and development of an enhanced inertial navigation system that is to be integrated into the Morpheus autonomous underwater vehicle at Florida Atlantic University. The inertial measurement unit is based on the off-the-shelf Honeywell HG1700-AG25 3-axis ring-laser gyros and three-axis accelerometers and is aided with ground speed measurements obtained using an RDI Doppler-velocity-log sonar. An extended Kalman filter has been developed, which fuses together asynchronously the inertial and Doppler data, as well as the differential Global Positioning System positional fixes whenever they are available. A complementary filter was implemented to provide a much smoother and stable attitude estimate. Thus far, preliminary study has been made on characterizing the inertial navigation system-based navigation system performance, and the corresponding results and analyzes are provided     

Resolving the pulsations of subdwarf B stars: PG 0154+182, HS 1824+5745 and HS 2151+0857

We continue our programme of extended single-site observations of pulsating subdwarf B (sdB) stars and present the results of extensive time-series photometry to resolve the pulsation spectra for use in asteroseismological analyses. PG 0154+182, HS 1824+5745 and HS2151+0857 were observed at the MDM Observatory during 2004 and 2005. Our observations are sufficient to resolve the pulsations of all three target stars. We extend the number of known frequencies for PG 0154+182 from one to six, confirm that HS 1824+5745 is a monoperiodic pulsator and extend the number of known frequencies to five for HS 2151+0857. We perform standard tests to search for multiplet structure, measure amplitude variations as pertains to stochastic excitation and examine the mode density to constrain the mode degree ℓ.     

地壳波浪运动机制探讨

讨论了地壳波浪运动形成的机制及其效应 ,并为地壳波浪状镶嵌构造学说提供了初步的数理模型和理论依据。