The harmonious character in equilibrium aeolian transport on mixed sand bed

Wind tunnel experiments were carried out to measure the spatial distribution in equilibrium transport of four types of mixed sand. The flux profiles of each grain size group were calculated. It is found that the vertical distribution of mean grain size has a close relation with the grain size distribution in the sand bed. In a log-linear plot, the flux profiles of main grain size groups are all straight lines and their slopes are nearly equal. It is also found that the ratio of transport rate of each size group to the whole transport rate is directly proportional to the mass ratio of each size group in the sand bed and the proportion value is only dependent on the grain size. This harmonious law is applicable to all four types of mixed sand used in the experiment.     

建立地震发射台的建议

目前地球上有成千上万个地震台，但它们都是接收地震波的地震台。建议建立一种新型的地震台，这种地震台用人工的方法不断地向外发射地震波，照亮需要研究地区的地下结构，研究特定的科学问题。建立地震发射台的核心问题是选择合适的人工震源，近年来出现的绿色环保震源，以及现代信息处理技术的发展，使得建立照亮10万km2(深至Moho面)地区地下结构的地震发射台已经完全是可能的。     

沉积物粒度对水合物形成的制约：来自IODP 311航次证据

对取自IODP 311航次（东北太平洋Cascadia大陆边缘）所有5个站位、采样间距约为1.5 m的614件沉积物样品，利用Beckman Coulter LS 230激光粒度仪进行了沉积物粒度分析，获得了沉积物粒度随深度变化特征，进而与水合物层位的替代指标进行了位置对比，这些指标包括特殊沉积构造（soupy和mousse like构造）、测井数据（LWD）推算出来的水合物饱和度（Sh）、岩芯红外图像和实际钻取的含水合物沉积物等。发现沉积物粒度分别为31~63 μm和63~125 μm的2组较粗粒径的沉积物数量变化增多的位置与水合物出现层位之间存在较好的位置对应关系。如在U1326站位海底以下5~8 m、21~26 m、50~123 m、132~140 m、167~180 m、195~206 m、220~240 m深度位置出现了沉积物粒度明显偏向粗粒的趋势，而这些位置正好对应于大多数特殊沉积构造出现的深度，也对应于水合物饱和度（Sh）值相对较高的深度，并与一些实际钻取的赋含水合物的浊积沙层观察结果一致。因此，初步研究后认为，沉积物粒度在水合物形成过程中扮演了重要角色，天然气水合物可能偏向形成于粒度大于31 μm的粗粒沉积物中。       

NOAA相邻卫片的自动镶嵌

图象镶嵌是个麻烦而且费时的工作。本文通过分析相邻图象的关系，给出了图象自动镶嵌的算法，即通过寻找相邻图象象素最小偏差平方和出现的位置来自动确定镶嵌需要偏移的行列数，这种方法容易实现。通过对NOAA图象镶嵌的试验，表明该算法是有效的。     

Predicting channel patterns

The proposed distinction between meandering and braided river channel patterns, on the basis of bankfull specific stream power and bed material size, is analysed and rejected. Only by using regime-based estimates of channel widths (rather than actual widths) has discrimination been achieved, and it is argued that this procedure is unacceptable.An alternative is to explore the patterning processes underlying the marked pattern scatter on bankfull stream power/bed material size plots. Of the five sets of patterning processes, large-scale bedform development and stability is seen as especially important for meandering and braiding. For gravel-bed rivers, bedforms developed at around or above bankfull stage appear important for pattern generation, with braiding relating to higher excess shear stress and Froude number. There seems to be an upper threshold to both meandering and braiding which is achieved at extreme discharges and steep gradients, as on steep alluvial fans, rather than for the rivers with available flow data here considered. For sand-bed rivers with greater excess shear stress, the equivalent upper plane bed threshold may occur below bankfull, with bed material mobility and bedform modification occurring over a wider range of sub-bankfull discharges. Sand-bed channel margin outlines appear to be less perturbed by bedform effects than gravel bed planforms, and they may have naturally straight or sinuous planforms. Bedform relief may nevertheless lead to some being designated as braided when viewed at low flows.It is concluded that the use of a single-stage stream power measure and bed material size alone is unlikely to achieve meandering/braiding discrimination.     

多源信息的集成与融合及其在遥感制图中的优化利用

多源信息的集成和融合是地球信息科学领域的一大热点问题。它的意义和必要性与地球信息本身的特征、采集信息的手段特征及信息处理平台或系统的特点三方面紧密相联系。本文从不同传感器信息的集成和融合、遥感信息与非遥感地学信息的集成和融合、不同格式的 GIS数据的集成和复合三个方面研究了多源信息集成和融合的方法、前沿技术和应用领域,进而以黄土高原土壤侵蚀遥感调查和制图任务为例,介绍了多源信息集成和融合技术在该项目中的优化应用实例,包括技术流程分析、信息源分析、多源信息在土壤侵蚀遥感调查和制图中的融合方法、从遥感图像解译信息到 GIS数据库的转换技术等。     

图象恢复在工业CT中的应用

对于以影象增强器为检测系统的目标旋转式工业ＣＴ，分析了其图象退化的因素，采用对一维投影数据进行图象恢复的方法来提高ＣＴ图象质量。文中给出图象恢复公式，从计算机模拟和实验图象恢复的结果可看到所用方法提高了图象清晰度。     

我国人均粮食变化的地理研究

人均粮食占有量是反映粮食供给水平的重要指标，本文分析了我国人均粮食占有量变化的阶段和地理特征，并探讨了其与粮食增产的关系，对因地制宜调控人粮关系有一定参考价值。     

多级SPOT立体影像匹配

立体影像匹配是自动提取SPOT影像高程信息的关键技术。本文根据SPOT影像在几何构像关系和影像质量上的特点,提出了多级匹配的结构策略。实际像对匹配实验表明,多级匹配法具有较好的可靠性和精度水平,而且运算速度快,在快速生成DEM数据辅助遥感信息分析方面,有重要的应用价值。     

Textural analysis and modelling of a flood deposit: River severn,U.K.

Samples of sediment collected from the Severn floodplain between Worcester and Gloucester following the severe flooding in January and February 1990, were analysed for their grain size distribution. The results show that most sand was deposited within 20 m of the channel bank, but that fine sand may contribute to flood sediment across the width of the floodplain. James' (1985) numerical model of overbank sedimentation attempts to predict the transfer of sediment to the floodplain during flooding. Geometrical and hydraulic data relating to the Severn flood are used as input for a computer program of James' (1985) model. The pattern of sediment concentrations predicted by the model was compared with that obtained from statistical analysis of the flood sediment. The patterns were found to be similar, so James' (1985) model was considered to predict in a relative sense the distribution of flood sediment.