国产高分辨率遥感影像辐射质量改善方法研究

受制于光学器件的性能与观测环境的影响,国产高分辨率遥感影像通常存在条带噪声、光谱分辨率低、纹理不清晰等问题,给后续的自动化影像产品生产及目标解译工作带来极大的不利。本研究先后从去除条带噪声、对比度增强、边缘增强三个方面,对遥感影像进行质量改善,使遥感影像更好地为地理信息公众服务。以高分二号全色影像为实验数据,目视和定量评价结果均证实了本文算法的有效性。     

雄安新区雾迷山组岩溶裂隙发育特征

雄安新区碳酸盐岩岩溶热储是具有重大开发潜力的优质地热资源。理清雾迷山组储层中岩溶裂隙的形成演化过程及发育特征,对地热资源的形成与聚敛研究具有重要作用,也是合理有效地开发地热资源的前提。根据岩芯采样、薄片、钻井、测井等资料,对雾迷山组岩溶裂隙的形成演化与几何特征进行了详细分析。结果表明:雄安新区岩溶和裂隙的形成与构造活动密切相关,以印支运动晚期至喜马拉雅运动期间最为强烈,形成了最有利储层发育的岩溶裂隙。雾迷山组裂隙带平均厚度和平均间隔分别为4.70m和4.05m,储厚比平均为41.90%。储层内部裂隙的走向主要为近北东向,倾角集中在50°～90°之间。面积裂隙频率达到5.34条/m²。裂隙的长度和开度平均分别为1.20m和95.16μm。多种物质充填裂隙,以白云石、黄铁矿、石英最为常见,含有数量较多的半充填和未充填裂隙。现今地应力有助于裂隙的开启,储层中裂隙网络发育,连通性好,具有非常好的导水储水性能,为雾迷山组地热资源富集提供了良好条件。     

u‐p semi‐Lagrangian reproducing kernel formulation for landslide modeling

This paper presents a u‐p (displacement‐pressure) semi‐Lagrangian reproducing kernel (RK) formulation to effectively analyze landslide processes. The semi‐Lagrangian RK approximation is constructed based on Lagrangian discretization points with fixed kernel supports in the current configuration. As a result, it tracks state variables at discretization points while allowing extreme deformation and material separation that is beyond the capability of Lagrangian formulations. The u‐p formulation following Biot theory is incorporated into the formulation to describe poromechanics of saturated geomaterials. In addition, a stabilized nodal integration method to ensure stability of the domain integration and kernel contact algorithms to model contact between bodies are introduced in the u‐p semi‐Lagrangian RK formulation. The proposed method is verified with several numerical examples and validated with an experimental result and the field data of an actual landslide.     

Radiative Shock Experiments At Luli

We present the set-up and the results of a supercritical radiative shock experiment performed with the LULI nanosecond laser facility. Using specific designed targets filled with xenon gaz at low pressure, the propagation of a strong shock with a radiative precursor is evidenced. The main measured quantities related to the shock (electronic density, propagation velocities, temperature, radial dimension) are presented and compared with various numerical simulations.     

Different Asian Monsoon Rainfall Responses to Idealized Orography Sensitivity Experiments in the HadGEM3-GA6 and FGOALS-FAMIL Global Climate Models

Recent work has shown the dominance of the Himalaya in supporting the Indian summer monsoon(ISM),perhaps by surface sensible heating along its southern slope and by mechanical blocking acting to separate moist tropical flow from drier midlatitude air.Previous studies have also shown that Indian summer rainfall is largely unaffected in sensitivity experiments that remove only the Tibetan Plateau.However,given the large biases in simulating the monsoon in CMIP5 models,such results may be model dependent.This study investigates the impact of orographic forcing from the Tibetan Plateau,Himalaya and Iranian Plateau on the ISM and East Asian summer monsoon(EASM) in the UK Met Office's Had GEM3-GA6 and China's Institute of Atmospheric Physics FGOALS-FAMIL global climate models.The models chosen feature oppositesigned biases in their simulation of the ISM rainfall and circulation climatology.The changes to ISM and EASM circulation across the sensitivity experiments are similar in both models and consistent with previous studies.However,considerable differences exist in the rainfall responses over India and China,and in the detailed aspects such as onset and retreat dates.In particular,the models show opposing changes in Indian monsoon rainfall when the Himalaya and Tibetan Plateau orography are removed.Our results show that a multi-model approach,as suggested in the forthcoming Global Monsoon Model Intercomparison Project(GMMIP) associated with CMIP6,is needed to clarify the impact of orographic forcing on the Asian monsoon and to fully understand the implications of model systematic error.     

GIS专业基于面向对象程序设计的DEM生成教学实验设计

数字高程模型是地理信息科学专业的必修课,DEM生成方法是该课程的核心知识点之一。通常以GIS软件为实验操作平台构建DEM,GIS软件提供良好的操作界面且简化教学过程,但软件同时会弱化学生对DEM生成过程的理解,而面向对象程序设计课程往往开设在数字高程模型课程之前。文中融合面向对象程序设计和数字高程模型课程知识点,采用面向对象程序设计思想对DEM课程中的DEM生成实验进行设计并实现,为GIS专业的DEM生成实验提供新的教学思路,提升DEM课程教学实践的品质和效果。     

太阳轨迹空间连续性的日照分析算法优化

针对日照分析模拟必须考虑众多真三维地形/地物的遮挡因素,传统的日照分析方法难以在现实世界的复杂地理场景中得出高效、准确分析结果的问题展开研究,基于太阳运行轨迹的空间连续性,利用数据缓存方法对遮挡图元进行预判,实现了日照分析算法的优化。应用实例表明,将该方法与空间划分方法配合使用,可以在保证运算结果正确的基础上,进一步提高日照分析的计算效率,从而实现复杂地理场景中准确、快速的日照分析计算。     

中国主要城市旅游要素网络关注空间演化特征

旅游要素发展水平是衡量旅游产业成熟程度的重要标志。通过建立旅游"六要素"搜索关键词选取、搜索数据剥离及合成的技术方法,结合2011-2015年我国24个主要城市旅游要素网络关注度数据,采用变差系数、赫芬达尔系数等指标和标准差椭圆方法,分析城市旅游要素的网络关注指数空间演化特征。结果表明:2011至2015年,"吃、住、行、娱"四要素网络关注指数城市差异呈"V"字趋势波动,"购"要素差异越来越大,"游"要素差异则越来越小;旅游"六要素"网络关注指数的赫芬达尔系数变化不大,各城市度集聚程度低,关注较为分散;旅游"六要素"网络关注指数在空间扩展上具有极大相似性,呈现出东北—西南格局,向正东—正西方向转变的趋势。但"吃、住、行、购"等旅游要素网络关注指数标准差椭圆的中心呈现向西南偏移的趋势,而"游、娱"旅游要素则呈现出向东北偏移的趋势。     

地球化学组成揭示的杜蒙沙地化学风化和沉积再循环特征及其对风尘物质贡献的指示

对杜蒙沙地的河流冲积砂、河漫滩泥质粉砂、沙质古土壤和风成沙等不同类型沉积物进行了采样（27组）,对这些样品的细颗粒组分（<63 μm）进行了常量元素、微量元素、稀土元素（REE）和Sr-Nd同位素比值等地球化学分析,就杜蒙沙地的化学风化、沉积再循环特征及其对风尘物质的贡献等展开了讨论。结果显示,杜蒙沙地的地球化学组成表现出空间的均一性,低的化学蚀变指数CIA（48~56,平均52）及A-CN-K和A-CNK-FM图解均表明了杜蒙沙地仅遭受了低级的化学风化程度。沙地的成分成熟度较低,大部分河流沉积物表现出初次循环沉积特征,系大兴安岭东侧中酸性岩浆母岩风化剥蚀的产物经嫩江搬运堆积形成;古土壤表现出与河流沉积物相同的初次循环特征,表明古土壤的成土母质是河流沉积物,这与野外地层出露情况一致;风成沙表现出再循环沉积特征,系河流沉积物就地起沙搬运堆积形成。不活动元素比值、REE和Sr-Nd同位素比值等物源判别图解,结合植被和地貌状况,一致表明杜蒙沙地与东北平原中东部的风尘物质没有地球化学亲缘关系,其对该地区（甚至下风向更远地区）的大气风尘的贡献很小。     

胸腹部双螺旋CT扫描与临床应用

报告了２５００例胸腹部双螺旋ＣＴ扫描，胸部１０７５例，其中肺恶性肿瘤４０８例，肺炎性疾病３０１例，结核１０８例，胸膜疾病７５例，纵隔肿瘤和转移瘤５４例，腹部１４２５例，其中肝硬化、肝恶性肿瘤４２７例，良性病变１５６例，胰腺为、胰腺癌１１５例，肾、肾上腺肿瘤１９５例，其它胸部和腹部如：肝、胆囊、消化道及腹膜后疾病２３２例，余者共４２９列示查出病变。上述疾病均经临床或病理证实。双螺旋ＣＴ扫描的优点是速