Wave measurement based on light refraction

Some authors have developed a few methods of measuring wave slopes based on light refraction, including the measurement method via the distribution of light intensity or color under water. A new method based on light refraction is specified for the measurement of wave surface elevation in wave flume via imaging technology. A plane painted with black and white stripes is put on the flume floor as an indication plane, which can be arranged easily and cheaply. Compared with the previous methods, the present method is less sensitive to the noise and nonlinear effects of optical process, which can be taken as a digital method. The CCD camera is fixed above the flume with its optical axis arranged vertically to grab the images of stripes modulated by the wave surface. The modulated value can be calculated from the Hilbert transform, and then the wave surface elevation can be obtained. The algorithm and experimental procedure are specified in detail, and some experimental results are provided to show the validity of the present method.     

Wave measurement based on light refraction

Some authors have developed a few methods of measuring wave slopes based on light refraction, including the measurement method via the distribution of light intensity or color under water. A new method based on light refraction is specified for the measurement of wave surface elevation in wave flume via imaging technology. A plane painted with black and white stripes is put on the flume floor as an indication plane, which can be arranged easily and cheaply. Compared with the previous methods, the present method is less sensitive to the noise and nonlinear effects of optical process, which can be taken as a digital method. The CCD camera is fixed above the flume with its optical axis arranged vertically to grab the images of stripes modulated by the wave surface. The modulated value can be calculated from the Hilbert transform, and then the wave surface elevation can be obtained. The algorithm and experimental procedure are specified in detail, and some experimental results are provided to show the validity of the present method.     

答“评‘紫坪铺水库造成孔隙弹性耦合变化及其对2008年汶川地震触发作用’二维模拟的局限性”

程惠红等(2015)在"评‘紫坪铺水库造成孔隙弹性耦合变化及其对2008年汶川地震触发作用’二维模拟的局限性"一文中提出,陶玮等(2014)采用二维模型模拟紫坪铺水库造成孔隙弹性耦合变化是一个不足,夸大了汶川地震震源处库仑应力增长值.我们认为采用二维模型模拟水库造成汶川地震震源处库仑应力变化确实可能存在一定偏差,但不会如程惠红等认为的"与三维模型相比夸大三倍".这是因为在程惠红等引用的论证中,二维模型计算中选取了接近水库最大剖面宽度而不是水库平均剖面宽度作为加载量参数,造成计算得到震源处库仑应力明显夸大.此外,陶玮等(2014)提出论断的主要依据不是"震源处"库仑应力值的大小,而是紫坪铺水库蓄水"由浅入深影响到整条断层,尤其对浅层范围的加载作用明显,达上百千帕,为整个断层面的失稳提供了基础".初始破裂的发生既可能是由水库蓄水引起,也可能是并非水库蓄水造成的一次普通构造小震,但其发生引发断层面上部已被水库蓄水弱化部分的连锁失稳而发生大震.即汶川地震既可能为直接触发也可能为间接触发,而我们的研究结果认为地震的发生完全可能由间接触发产生.若仅纠结于"震源处"的库仑应力变化,则忽视了水库蓄水影响的主体.水库蓄水对地震触发作用是一个复杂问题,相对这一问题所涉及的一系列不确定性因素来说,二维模拟的局限性所造成的影响并不很大也不是最大的,也不妨碍我们据此得出紫坪铺水库蓄水促进汶川地震发生的结论.     

中、强震前川滇块体遥感红外辐射异常分析——以宁蒗M5.7地震和鲁甸M6.5地震为例

许多研究表明中强地震前出现了红外辐射异常。近年来,川滇块体中、强地震频发,利用遥感数据对其红外辐射异常变化开展深入分析十分必要。结合13年MODIS/Terra遥感红外数据,采用空间距平分析法、辐射增强阈值面积指数法及辐射亮温均值低频时间序列法,对2004年4月—2017年6月红外亮温数据进行深入分析,研究川滇块体及周边构造断裂M≥5.5地震的震前异常信息。结果表明:(1)M≥6.0地震在震前3～6个月川滇块体会出现较为明显的红外辐射增强异常现象;(2)震前红外异常并非随机分布,而可能是受到相关块体的控制;(3)以宁蒗M5.7地震和鲁甸M6.5地震为例研究发现,震前辐射增强较高的小范围区域与震中位置存在一定关联。     

相变储能材料六水氯化钙的储热性能优化研究

六水氯化钙(CaCl2?6H2O)的相变温度约为29 ℃,相变潜热约180.0～190.8 J/g,因其潜热高,成本低,无毒等优点广泛应用于建筑材料中,但CaCl2?6H2O在实际应用中存在着储热性能差、衰减严重等缺点。通过差示扫描量热法(DSC)、原子力显微镜(AFM)、X射线衍射法(XRD)对比了CaCl2?6H2O在改性前后的潜热性能、形貌及晶体结构差异。结果表明,通过对CaCl2?6H2O的水含量进行精确调控,材料的相变潜热从158.6 J/g提升至194.8 J/g,潜热存储能力得到极大的提升。     

Geospatial Information Service Based on Digital Measurable Image——Take Image City·Wuhan as an Example

LBS (location-based service) is a remarkable outcome of the development from GIS to geospatial information service. Faced by the requirements of geospatial information from the masses and the opportunity provided by the next generation Internet and Web 2.0, a new model of geospatial information service based on DMI (digital measurable image) is presented. First, the concept of LBS and the opportunities of Web 2.0 are introduced, then the characteristic of DMI is discussed. Taking the Image City·Wuhan as an ...     

利用互信息改进遥感影像朴素贝叶斯网络分类器

针对朴素贝叶斯网络简单条件独立性假设的不足,将它的一种改进形式——选择型朴素贝叶斯网络和两种扩展形式(树增强型朴素贝叶斯网络、贝叶斯增强型朴素贝叶斯网络)用于多光谱遥感影像的分类中。在分析波段间互信息的基础上,分别构造了上述3种分类器,并和朴素贝叶斯网络分类器的性能进行了比较。     

一种有效的复杂多边形裁剪算法

提出了一种基于扫描线思想和梯形分割技术的多边形裁剪算法,其主要步骤包括:计算主多边形(集)与窗口多边形(集)的交点,提取所有交点和多边形边界结点的纵坐标(y)并进行排序;以排序后的y作水平扫描线,分别对主多边形和窗口多边形进行梯形分割,获得两组梯形集合;对这两组梯形集合逐行执行梯形单元"交"运算,最后对结果交集进行边界追踪建立裁剪多边形。实验结果表明,该算法具有较好的计算效率,是一种比较实用的多边形裁剪算法。     

高分辨率遥感影像多尺度均值漂移分割算法研究

根据高分辨率遥感影像信息提取过程中对影像的对象化分割的需求,分析了均值漂移分割算法的原理,并对其多尺度分割方法进行了设计与实现。实验证明该算法具有较好的影像分割精度。     

基于Google Earth的气象多参数综合显示系统

利用Google Earth平台,将天气过程中的雷电、红外云图、MICAPS高空图以及TMPA降水资料,通过编写KML/KMZ文件,建立了气象多参数综合显示系统。该系统平台的建立,可在三维空间中真实动态地再现天气的发生发展及演变过程。此平台将有利于灾害性天气成灾过程和物理机制的研究。