基于粒子群算法的高光谱影像端元提取技术

基于凸面几何学理论,由端元作为角点的单形体的体积应该是最大的.著名的N-FINDR和SGA算法正是基于以上理论,通过在数据云中寻找体积最大的单形体来实现端元的自动提取.本文利用粒子群优化(PS0)技术,基于凸面几何学理论,设计了一个新的端元提取算法.利用模拟和真实高光谱影像对其进行了实验,并将其结果与N-FINDR和S...     

海底入射角对多波束反向散射强度的影响及其改正

综合考虑测船姿态、声线弯曲和海底地形对入射角的影响,推导了计算多波束海底入射角的实用模型。根据Lambert法则,改正海底入射角对反向散射强度的影响。实例计算结果表明,所述模型能精确地计算波束在海底的入射角,有效地改正其对反向散射强度的影响。     

3维城市模型理论及技术方法研究

主要研究了3维城市模型的相关理论与技术,提出了拓扑关系、尺度及可视化等问题,讨论了3维城市模型的建设方法及关键技术,并对3维城市模型的发展进行了展望。     

利用小波变换方法识别山西形变异常信息

文章主要根据小波变换方法在不同尺度时细节的变化特征,通过一些震例对山西数字形变资料进行分析研究,发现,经过小波变换处理后的数据在细节部分达到第5层、第6层时,震前资料会显示出比较同步的长周期信号,这为识别和提取数字洞体形变资料中的趋势异常和短期异常提供了新的探索思路和方法。     

太原基准地震台数字地震仪震级偏差分析及校正

选用太原基准地震台2008年至2009年的数字化地震仪面波震级资料,以中国地震台网中心正式报告给出的震级为标准震级,进行了震级偏差统计分析。结果表明,该台的绝大部分震级偏差△M≤0．2级,部分地区地震震级偏差较大（超过0．3级）需进行校正。     

湖相沉积盆地内隐伏断裂的电阻率层析成像探测——以通海盆地为例

本文利用电阻率层析成像方法对湖相沉积盆地——通海盆地内的小江断裂的西支断裂进行了探测。发现在电阻率图像的较深区域才能识别出断裂的位置和产状,它在通海盆地内的走向约为N47°E,倾角约为57°～66°,视倾向为NW或N,与以往的研究结果基本一致。     

青藏高原一次强对流过程对水汽垂直输送的数值模拟

本文采用中尺度天气研究预测模式(WRF)模拟了青藏高原那曲地区的一次强对流过程,分析了强对流对水汽的垂直输送量及对模式不同云微物理参数化方案的敏感性.通过与实测资料的比较,发现此次模拟在对流发生时间、地点、降水时间等方面均与实际接近.敏感性试验表明:当对流发生时,对流区域向上的水汽通量随海拔高度呈先增大后减小的趋势,该...     

青海木里冻土区水合物稳定带的特征研究——模拟与钻探结果对比

基于青海木里冻土区的气体组成、钻孔泥浆的温度测量数据等对该区水合物稳定带的顶底深度进行了模拟计算,并将计算结果与钻探揭示的水合物产出深度进行了对比.模拟计算的水合物顶深在148.8～122.7 m 间,底深在324.6～354.8 m间,水合物厚度在175.8～232.2 m间,钻探揭示水合物及其异常产出在133～39...     

Variation of mineral composition,fabric and oxygen fugacity from massive to foliated eclogites during exhumation of subducted ocean crust in the North Qilian suture zone,NW China

Eclogites from the North Qilian suture zone are high‐pressure low‐temperature metamorphic rocks of ocean crust protolith, and occur in both massive and foliated varieties as individual blocks of tens to hundreds of metres in size. The massive type is weakly deformed and shows granoblastic texture characterized by a coarse‐grained peak mineral assemblage of Grt¹ + Omp¹ + Ph + Rt ± Lws (or retrograde Cz). In contrast, the foliated type is strongly deformed and shows a fine‐grained retrograde mineral assemblage of Grt² + Omp² + Cz + Gln + Ph. Both total FeO and aegirine contents in omphacite, as well as X_Fe[=Fe³⁺/(Fe³⁺ + Al^VI)] in clinozoisite/epidote, increase significantly from massive to foliated eclogites. Lattice preferred orientation (LPO) of omphacite, determined by electron back‐scatter diffraction analysis, is characterized by weak and strong SL‐type fabrics for massive and foliated eclogites, respectively. Clinozoisite/epidote also developed SL‐type fabric, but different from the LPOs of omphacite in <010> and <001> axes, owing to their opposite crystallographic long and short axis definitions. The transition of deformation mechanism from dislocation creep to diffusive mass transfer (DMT) creep in omphacite and the concomitant retrograde metamorphism both are efficiently facilitated when the original coarse‐grained Omp¹ + Grt¹ + Lws assemblage is dynamically recrystallized and retrogressed into the fine‐grained Fe³⁺‐rich assemblage of Omp² + Grt² + Cz + Gln. The DMT process with concomitant anisotropic growth assisted by fluids is considered to be an important deformation mechanism for most minerals in the foliated eclogite. P–T estimates yielded 2.3–2.6 GPa and 485?510 °C for the massive eclogite and 1.8–2.2 GPa and 450?480 °C for the foliated eclogite. The significant increase in total Fe and Fe³⁺ contents in omphacite and clinozoisite/epidote from massive to foliated eclogite suggests changes in mineral compositions accompanied by an increase in oxygen fugacity during ductile deformation associated with exhumation. The LPO transition of omphacite, clinozoisite and rutile from weak SL‐type in massive eclogites to strong SL‐type in foliated eclogites is interpreted to represent the increment of shear strain during exhumation along the ‘subduction channel’.     

一种基于数据机制的DBM模型及其应用

将DBM(Data Based Mechanistic)模型应用到辽东森林小流域——大湖沟,分别以其2006年6月和2007年7月数据构建研究区丰水期和枯水期的DBM模型,拟合效率系数分别为0.952 8和0.837 8,模型拟合效果在验证期的不同时段表现出明显的差异性。对丰水期模型参数用固定时间间隔法(FIS)进行时变性分析,发现参数b的取值随时间产生变化。对枯水期的二阶DBM模型进行快、慢流分解,得出了连续时间当量的快、慢流的平均滞后时间分别为5.3h和243.3h。