搜索结果: 16-30 共查到“知识库 天文动力学”相关记录54条 . 查询时间(2.14 秒)
GPS全球电离层 TEC的并行算法建模及初步结果分析
GPS 全球电离层 TEC 模型 DCB 并行算法
2013/4/9
根据高精度卫星导航定位和全球电离层活动监测的需要，利用全球 370 多个 GPS 基准站的双频相位实测数据，监测全球电离层总电子含量变化和 GPS 卫星及接收机的 DCB。由于数量大、数据处理时间长，很难实现高精度快速建模，为此我们采用 OpenMP 并行算法来加快数据处理速度。实验表明，相对于串行处理，并行处理在 8 核服务器下能加速 7 倍以上，在 48核服务器下能加速超过 40 倍。将本文的...
利用 IGS星历预报 GPS卫星轨道
GPS IGS 轨道拟合 轨道预报
2013/4/9
在动力学轨道拟合以及轨道积分的基础上，提出了基于 IGS 精密星历的 GPS 卫星轨道预报方法。该方法首先利用已知的 IGS 精密星历作为虚拟观测值，采用动力学方法拟合出 GPS卫星的初始轨道和动力学参数，然后再通过积分来预报 GPS 卫星的轨道。主要讨论了基于不同弧段的 IGS 星历时，该方法对 GPS 卫星轨道的拟合和预报情况。研究结果显示：对于 6 d 弧段以内的 IGS 精密星历，其拟合轨...
2010年上海天文台卫星激光测距观测报告
卫星激光测距 千赫兹白天测距 同步轨道卫星 空间碎片
2013/4/9
介绍了 2010 年上海天文台卫星激光测距的常规观测和白天千赫兹激光测距情况。在国际上首次对同步轨道卫星开展了千赫兹激光测距，作用距离达 38 800 多千米，测距系统性能达到国际先进水平。利用 2 套独立的激光测距系统，开展了激光收发分离测距实验，为行星际异步应答式激光测距模拟试验提供了实测数据。最后概述了空间碎片目标激光测距进展情况。
基于重要样本法的结构动力学系统的首次穿越
首穿失效概率 重要抽样法 设计点激励 镜像法
2014/3/3
基于Gisranov定理, 提出一种估计稳态高斯白噪声激励的结构动力学系统首穿失效概率的重要样本法. 文章重点是构造控制函数, 控制函数促使随机响应尽量集中在样本空间中最易导致首次穿越发生的部分. 利用设计点构造控制函数, 在线性系统场合, 结合时不变系统的结构可靠性理论, 通过解有约束的优化问题得到设计点; 在非线性系统场合, 利用Heonsang Koo提出的设计点激励, 通过镜像法得到设计点...
采用高速纹影法实验研究了柱形汇聚激波与球形重气体界面相互作用的 Richtmyer-Meshkov不稳定性问题. 激波管实验段基于激波动力学理论设计, 将马赫数为1.2 的平面激波转化为柱形汇聚激波, 气体界面由肥皂膜分隔六氟化硫(内)和空气(外)得到. 采用高速摄影机在单次实验中拍摄激波运动的全过程, 对柱形激波的形成进行了实验验证, 并进一步观测了汇聚激波与球形气体界面相互作用过程中的波系发展...
Randall-Sundrum limit of f(R) brane-world models
Randall-Sundrum limit brane-world models
2011/10/17
By setting some special boundary conditions in the variational principle we obtain junction conditions for the five-dimensional $f(R)$ gravity which in the Einstein limit $f(R)\rightarrow R$ transform...
Galaxy-Scale Outflows Driven by Active Galactic Nuclei
Galaxy-Scale Outflows Driven Active Galactic Nuclei
2011/10/20
We present hydrodynamical simulations of major mergers of galaxies and study the effects of winds produced by active galactic nuclei (AGN) on interstellar gas in the AGN's host galaxy. Motivated by th...
Very Long Baseline Array Imaging of Parsec-scale Jet Structures in Radio-loud Narrow-line Seyfert 1 Galaxies
Long Baseline Array Imaging Radio-loud Narrow-line Seyfert
2011/10/21
We conducted very long baseline interferometry (VLBI) observations of five radio-loud narrow-line Seyfert 1 (NLS1) galaxies in milliarcsecond resolutions at 1.7 GHz (18 cm) using the Very Long Baselin...
The Orbital Period and Variability of the Dwarf Nova ES Draconis
stars: individual: ES Dra (PG 1524+622) – novae: cataclysmic variables – binaries: spectroscopic – AAVSO
2011/10/12
A radial velocity study of the cataclysmic variable ES Dra (PG 1524+622) is presented. ES Dra is found to have an orbital period of 0.17660 \pm 0.00006 d (4.2384 \pm 0.0014 h). The mass-losing seconda...
Dynamical chaos in the problem of magnetic jet collimation
galaxies: jets – magnetic fi elds – MHD – ISM: jets and outfl ows – ISM:kinematics and dynamics
2011/10/12
We investigate dynamics of a jet collimated by magneto-torsional oscillations. The problem is reduced to an ordinary differential equation containing a singularity and depending on a parameter. We fin...
Quantum gravity stability of isotropy in homogeneous cosmology
quantum stability cosmological isotropy cosmological
2011/10/17
It has been shown that anisotropy of homogeneous spacetime described by the general Kasner metric can be damped by quantum fluctuations coming from perturbative quantum gravity in one-loop approximati...
The Coalsack near and far
Sun: fl ares Methods:data analysis Methods:statistical Methods:observational
2011/10/8
Context: The large Coalsack dark cloud is one of the rare molecular clouds without clear signs of star formation. Aims: We investigate the dynamical properties of the gas within the Coalsack. Methods:...
We quantify the potential for testing MOdified Newtonian Dynamics (MOND) with LISA Pathfinder (LPF), should a saddle point flyby be incorporated into the mission. We forecast the expected signal to no...
Large Variations of the coefficient $J_2$ of geopotential, and the dynamical Love number $k_2^d$ from the analysis of laser ranging to LAGEOS~1 and LAGEOS~2
satellites geopotential tides Love numbers SLR ob- servations
2011/9/26
Secular and seasonal variations of the coefficient $J_2$ of the geopotential are studied from the analysis of laser measurements of distances to the geodetic satellites LAGEOS~1 (1988--2003) and LAGEO...