The Data Depth-weight-kernel Estimation of the Model Error of Satellite Orbit Determination

It is an objective fact that there exists error in the satellite dynamic model and it will be transferred to satellite orbit determination algorithm, forming a part of the connotative model error. Mixed with the systematic error and random error of the measurements, they form the unitive model error and badly restrict the precision of the orbit determination. We deduce in detail the equations of orbit improvement for a system with dynamic model error, construct the parametric model for the explicit part of the model and nonparametric model for the error that can not be explicitly described. We also construct the partially linear orbit determination model, estimate and fit the model error using a two-stage estimation and a kernel function estimation, and finally make the corresponding compensation in the orbit determination. Beginning from the data depth theory, a data depth weight kernel estimator for model error is proposed for the sake of promoting the steadiness of model error estimation. Simulation experiments of SBSS are performed. The results show clearly that the model error is one of the most important effects that will influence the precision of the orbit determination. The kernel function method can effectively estimate the model error, with the window width as a major restrict parameter. A data depth-weight-kernel estimation, however, can improve largely the robustness of the kernel function and therefore improve the precision of orbit determination.     

Invariant manifolds, phase correlations of chaotic orbits and the spiral structure of galaxies

In the presence of a strong   m = 2  component in a rotating galaxy, the phase-space structure near corotation is shaped to a large extent by the invariant manifolds of the short-period family of unstable periodic orbits terminating at L ₁ or L ₂. The main effect of these manifolds is to create robust phase correlations among a number of chaotic orbits large enough to support a spiral density wave outside corotation. The phenomenon is described theoretically by soliton-like solutions of a Sine–Gordon equation. Numerical examples are given in an N -body simulation of a barred spiral galaxy. In these examples, we demonstrate how the projection of unstable manifolds in configuration space reproduces essentially the entire observed bar–spiral pattern.     

Differential uplift between Beihuaiyang and Dabie orogenic belt

Isotope dating, hornblende geobarometer, fission-track analysis and fluid inclusion homogeneous temperature analysis have been applied to Caledonian, Variscan and Yenshan plutons in Bei Huaiyang (BHY) and Dabie orogenic belt (DOB), and the emplaced depths and ages of these plutons have been obtained in order to obtain differential uplift time and uplift heights between BHY and DOB since late Paleozoic era. BHY had experienced three stages of uplift (C1-C2, T-J2, J3-K1) and its total uplift height is about 10 km, but, DOB had only experienced two stages of uplift (T-J2, J3-K1) and its maximum uplift height is more than 15 km. BHY uplift occurred mainly before the mid-Jurassic (about 150 Ma), but DOB uplift took place after the mid-Jurassic (about 150 Ma).     

MIXTURE ANGLYSIS USING FACTOR ANGLYSIS I: CALIBRATION AND QUANTITATION

One of the major application areas of factor analysis, multivariate calibration and quantitation, is coveredin this review. The algorithms, methodologies and applications covered include principal componentregression, target transformation factor analysis, singular value decomposition and rank annihilationfactor analysis. Many important areas of research having relevance to multivariate calibration andquantitation problems are also covered in this review, including background correction, measurementerror, rank determination, cross-validation, figures of merit, detection of invalid samples, experimentaldesign, sample selection, statistical inference and wavelength selection.     

贵州施秉白云岩溶蚀特性及孔隙特征实验研究

以贵州施秉白云岩为研究对象,从宏观和微观角度分析白云岩的溶蚀特性及孔隙特征,结果显示:(1)在众多影响施秉喀斯特发育的因素中,矿物成分是最基本的内因,水是最关键的外因,孔隙结构起辅助作用。(2)极细晶白云岩的单位表面积溶蚀量一般大于细晶白云岩的,在晶粒相同的情况下,白云岩的溶蚀量与Ca O和Mg O的含量分别成正比,且Mg O的含量影响较Ca O大。(3)施秉白云岩溶蚀速率不仅受岩石矿物颗粒粒径大小的控制,还受岩石内部孔隙结构特征的影响,颗粒粒径越大,孔隙度越高,连通性越好,越有利于水溶液进入,溶蚀量也就越大。(4)施秉白云岩的溶蚀特性是多种因素综合作用的结果,必须把各个因素分离开来,从宏观和微观角度逐个作详细的分析研究,然后综合起来,才能对喀斯特发育规律有更深入的了解。     

On determining the noon polar cap boundary from SuperDARN HF radar backscatter characteristics

Previous work has shown that ionospheric HF radar backscatter in the noon sector can be used to locate the footprint of the magnetospheric cusp particle precipitation. This has enabled the radar data to be used as a proxy for the location of the polar cap boundary, and hence measure the flow of plasma across it to derive the reconnection electric field in the ionosphere. This work used only single radar data sets with a field of view limited to 2 h of local time. In this case study using four of the SuperDARN radars, we examine the boundary determined over 6 h of magnetic local time around the noon sector and its relationship to the convection pattern. The variation with longitude of the latitude of the radar scatter with cusp characteristics shows a bay-like feature. It is shown that this feature is shaped by the variation with longitude of the poleward flow component of the ionospheric plasma and may be understood in terms of cusp ion time-of-flight effects. Using this interpretation, we derive the time-of-flight of the cusp ions and find that it is consistent with approximately 1 keV ions injected from a subsolar reconnection site. A method for deriving a more accurate estimate of the location of the open-closed field line boundary from HF radar data is described.     

柯坪6.5级地震的部分前兆异常及预报

1991年2月25日柯坪6.5级地震前,震中附近地区的土层地应力、金属摆倾斜仪等多项前兆观测出现异常变化,说明强震发生前近场灵敏度较低的简陋仪器也能观测到明显的前兆反应。分析、认识这些异常对地震短临预报的决策是有益的。     

采用土工合成材料的新型护岸结构的动态数值模拟

固化土和土工格栅护岸工法（SG-WALL工法）是一种采用固化土和土工格栅加固港口护岸结构的新型工法。它的抗震性能已经通过一系列振动台试验得到了确认。为了能够数值再现SG-WALL结构在地震荷载作用下的动力反应,对SG-WALL结构的振动台试验进行了动态数值模拟研究。试验和模拟结果的对比表明,数值模拟方法能够再现SG-WALL结构在振动荷载作用下的主要动力特征。模拟结果还表明：固化土的长度对SG-WALL抗震性能起到重要的影响;土工格栅的最大拉应变发生在与排桩的连接处,并且沿着远离排桩的方向逐渐减小。     

岩溶洞穴次生碳酸盐沉积铀及其同位素组成古气候环境研究进展

洞穴沉积铀含量及其同位素初始234U/238U[（234U/238U)0]变化均与过去气候环境变化关系密切。文章分别对石笋中U含量和(234U/238U)0的气候意义进行统计分析发现,多数研究认为洞穴沉积U含量和(234U/238U)0可能指示土壤湿度和有效降水变化。然而,不管是对洞穴沉积的U含量还是(234U/238U)0,其气候环境意义解读还存在两种观点。但无论如何,这些研究成果都显示了洞穴沉积的U含量和(234U/238U)0是研究过去气候环境变化的重要替代指标。在未来的研究中,除了土壤环境和过程,还应关注U来源的相对贡献变化和其他微量元素与U元素的关系。这一指标可能在对东亚地区的大气粉尘活动和冬季风演化、地表生物量的变化研究等方面发挥重要作用。      

我国岩溶资源环境领域的创新问题

中国岩溶地区资源环境问题突出,制约着经济社会的发展。“十八大”以来国家大力推进科技创新和生态文明建设。科技创新不仅有助于解决和应对岩溶地区的资源环境问题,也将推动岩溶科学的发展,服务我国生态文明建设。今后的岩溶研究应当落实地球系统科学在岩溶学中的应用,发挥我国岩溶研究的地域优势,探索我国岩溶关键带的特征和重要过程;加强岩溶作用应对全球变化、岩溶碳汇速率和稳定性的研究,建立应对极端气候的长效机制;考虑古纬度和古气候对古岩溶形成的影响;深入探索微生物对深部碳酸盐岩岩溶形成的作用;系统梳理和总结我国第一期石漠化治理工程的经验和存在的问题,更好地指导下一步的治理工作;思考从南北方岩溶分界线的角度开展岩溶自然遗产地的申报工作;将现代大数据等技术运用到岩溶资源环境、水文地质研究中,做好地质灾害的预警预报和应对资源短缺问题的研究,服务国家需求。