利用GPS水准点精化局部CQG2000

CQG2000模型的精度仍不能满足中、大比例尺的测图需要,如何充分利用现有成果,提高其价值和实用性,是目前需要迫切解决的问题。本文提出了通过加密GPS水准点来提高现有CQG2000精度的方法,并研究了GPS水准点数目和分布对提高结果的影响。     

GPS数据解算对流层天顶总延迟探讨

文中运用GAMIT/GLOBK 软件,解算了南极长城站GPS接收机天线在不同的相位中心和使用不同星历情况下的天顶总延迟,分析了在不同条件下解算结果的差异,探讨了获取高精度的天顶总延迟和实时获取天顶总延迟的具体方法,为今后实现GPS精密定位和实时天气预报提供了依据.     

捷联惯导MATLAB／Simulink仿真实现

阐述了MATLAB/Simulink的主要特点,设计了基于MATLAB/Simulink的捷联惯性导航仿真模型,给出了仿真实例和分析结果,表明利用MATLAB/Simulink可以提高仿真效率。     

河南理工大学校园导航系统的设计与实现

利用了SuperMap Objects组件,构建了C/S模式的河南理工大学校园导航系统,实现了信息查询、路径导航、办事指南、地图与数据编辑、数据输出、用户管理及三维虚拟校园导航等功能,并提供了与现有校园系统集成的接口.     

北京城市地表温度的遥感时空分析

运用Landsat TM/ETM+和Terra ASTER数据,对北京市1990~2007年夏季的地表温度进行了反演,并对地表温度的空间分布、时间变化作出了分析。对Landsat TM/ETM+数据的温度反演采用了普适性单波段算法,ASTER数据的温度反演采用了劈窗算法。通过对地表温度数据的直方图均衡处理以及综合对比分析,总结出北京地区历年来夏季地表温度的空间分布格局及该格局随北京城市发展的变化规律,分析了研究成果的不足,提出了下一步要努力的方向。     

CHRIS／PROBA高光谱数据的预处理

针对CHRIS／PROBA高光谱遥感数据的特点,对CHRIS影像进行去条带处理、辐射校正、大气校正等预处理,获得较好质量的影像,为影像的进一步分析和实际应用提供保障。     

地理信息服务中数据传输性能分析

地理信息服务系统具有数据密集型和计算密集型的特点,对网络环境的设置有着特殊的需求。本文从地理信息服务系统中对数据传输应用的角度出发,从网络数据传输协议的传输层和应用层两个层次分析地理信息服务系统应用的特殊性,并根据系统应用的特殊需求提出相应的解决方案,提高整个应用系统中各类数据传输的效率、性能和系统运行的稳定性,提高地理信息服务系统为多用户提供地图服务、位置服务以及各种应用服务的综合能力。提高系统适应多用户并发访问海量数据的地图服务作业和频繁访问实效性很强的位置服务作业的能力。     

西藏冈底斯矿带成矿作用及远景分析

冈底斯带矿床众多,类型复杂,主要有斑岩型铜（金钼）矿床、矽卡岩型铁铜-铅-锌（银）矿床、层控铅-锌-银矿床、火山岩型金-银矿床及雄村式铜-金矿床。矿床地质特征和同位素年龄表明,冈底斯带南部的矿床与新特提斯洋壳向北俯冲-陆陆碰撞及碰撞期后的构造岩浆事件有关;冈底斯带北部的矿床与班公湖-怒江洋壳向南俯冲-陆陆碰撞及碰撞期后构造岩浆事件有关。冈底斯带与洋壳的俯冲-碰撞有关的岩浆活动强烈,成矿条件优越。西藏高原在碰撞后发生了快速抬升剥蚀,部分矿床顶部出现低温组合矿化,多数矿床保存良好。     

Laser probe Ar/Ar dating: History and development from a technical perspective

The ⁴⁰Ar/³⁹Ar method using a laser probe opened the door to microscale measurements and diffusion profiles frozen in samples. In the first decade since the initial application of a laser for ⁴⁰Ar/³⁹Ar dating in 1973, practical applications have been few. This is due not only to the fact that the laser and vacuum technologies were immature but that mass spectrometry was also in its infancy. In those days, the sensitivity of a mass spectrometer was generally insufficient to measure the small amount of argon degassed from a geological sample by a laser. These problems have subsequently been solved by new technologies. To understand their current status, a brief history of their development is outlined. This outline focuses on the required detection limit in micro scale measurement, practical approaches for accurate measurement are explained through examples in our laboratory specifically relating to the technical aspects of ⁴⁰Ar/³⁹Ar dating.     

Determination of Sr/Sr mass-dependent isotopic fractionation and radiogenic isotope variation of Sr/Sr in the Neoproterozoic Doushantuo Formation

We measured both mass-dependent isotope fractionation of δ⁸⁸Sr (⁸⁸Sr/⁸⁶Sr) and radiogenic isotopic variation of Sr (⁸⁷Sr/⁸⁶Sr) for the Neoproterozoic Doushantuo Formation that deposited as a cap carbonate immediately above the Marinoan-related Nantuo Tillite. The δ⁸⁸Sr and ⁸⁷Sr/⁸⁶Sr compositions showed three remarkable characteristics: (1) high radiogenic ⁸⁷Sr/⁸⁶Sr values and gradual decrease in the ⁸⁷Sr/⁸⁶Sr ratios, (2) anomalously low δ⁸⁸Sr values at the lower part cap carbonate, and (3) a clear correlation between ⁸⁷Sr/⁸⁶Sr and δ⁸⁸Sr values. These isotopic signatures can be explained by assuming an extreme greenhouse condition after the Marinoan glaciation. Surface seawater, mixed with a large amount of freshwater from continental crusts with high ⁸⁷Sr/⁸⁶Sr and lighter δ⁸⁸Sr ratios, was formed during the extreme global warming after the glacial event. High atmospheric CO₂ content caused sudden precipitation of cap carbonate from the surface seawater with high ⁸⁷Sr/⁸⁶Sr and lighter δ⁸⁸Sr ratios. Subsequently, the mixing of the underlying seawater, with unradiogenic Sr isotope compositions and normal δ⁸⁸Sr ratios, probably caused gradual decrease of the ⁸⁷Sr/⁸⁶Sr ratios of the seawater and deposition of carbonate with normal δ⁸⁸Sr ratios. The combination of ⁸⁷Sr/⁸⁶Sr and δ⁸⁸Sr isotope systematics gives us new insights on the surface evolution after the Snowball Earth.