基于时间阻抗函数的路网可达性研究

阐述了可达性的概念和在不同学科的应用范围,分析了可达性的影响因素,总结了现阶段在几何拓扑学上 常用的可达性量化方法,指出重力模型法、距离法、累计机会法的使用条件和不足。在这一基础上,发现现存的问题 主要是局限于空间尺度的量化不能准确地反应空间网络的联系程度,针对此问题,提出了基于时间阻抗函数的量 化模型,以实际交通量作为主变量,能间接地反应空间需求强度。随后引入了节点重要度的概念,能更加直接地反 映路网节点上社会、经济、交通等因素对可达性的影响,能很好地弥补时空法和效用法的不足。     

River channel change: Problems of interpretation illustrated by the river derwent,north Yorkshire

Some inherent limitations of the spatial interpolation method of identifying and interpreting channel adjustment are illustrated by a study of the River Derwent in Yorkshire. Here, cross-sections downstream from a river diversion appear to have contracted in size when compared with predictions based on upstream relationships between channel form variables and basin area. However, these sections are slightly larger than expected for their diminished discharge, suggesting that they have not fully adjusted to altered environmental conditions and are still in a transient state.     

3维模型数据压缩技术分析

3维模型越来越广泛地应用于众多领域里,但有限的图形显卡的处理能力和网络带宽严重阻碍了这种媒体的传播。单纯依靠增加硬件设备的投入不足以解决问题,必须采用相应的算法对3维模型数据进行压缩。首先将3维模型数据压缩算法进行分类;然后结合不同的分类情况比较分析了近几年来有代表性的几种压缩算法;最后对该技术今后应着重研究的几个方面进行了总结和展望。     

GNSS双差定姿模型的精化

把GNSS双差定姿模型推广到km级短基线精密解算。指出常用的GNSS双差定姿模型存在几何上的系统偏差,该系统偏差严重影响km级基线的精密定位解算。提出了修正该系统偏差的方法,并把修正量加入定位模型,提高了模型的精确程度。采用两组实验数据分别对修正前和修正后的模型进行比较,验证了改进效果。     

重力资料精细处理及在珠江三角洲地震灾害研究中的应用

对于珠江三角洲地区的断裂构造问题及其在地震灾害中的作用，随着该区经济的迅速发展，又重新引起人们的重视。本文利用小波变换和分形几何等新的数学方法对珠江三角洲地区的重力资料进行了精细处理．并获得了一些新的认识，认为北东东向断裂是该区的重要断裂，是珠江三角洲地区地震灾害产生的主要原因。     

阿拉善地块南缘构造活动特征与青藏高原东北缘向外扩展的最新边界

青藏高原向北东方向扩展的方式及最新扩展边界的位置,是目前青藏高原东北缘构造变形研究的热点.基于近年来对阿拉善地块南缘及邻区活动构造运动特征调查和定量研究结果,重点总结了阿拉善地块南缘活动断裂几何图像及运动特征,指出以前普遍认为的稳定阿拉善地块内部在新生代晚期发育了一系列规模不等、运动性质各异的活动断裂,这些活动断裂是青...     

Evolution of fault geometry and development of strike-slip basins: Comparative studies on the transform zones in Turkey and Japan

Abstract Although the origins of pull-apart basins and push-up bulges have been discussed by numerous geologists, no discussion has been held on the development process of the basins based on recent active traces and Quaternary chronology. The author has investigated recent fault-active traces and fault topography in the Havza-Ladik, Erbaa-Niksar, Susehri-Golova and Erzincan sedimentary basins along the North Anatolian fault in northern Turkey and the Suwa basin along the Itoigawa-Shizuoka tectonic line (fault system) in central Japan. As a result of this investigation, the locations and sense of deformation of recent active traces seldom coincide with topographic scarps along basin margins in the studied basins. The fault traces have migrated from the basin margins to the center of the basins and become straight. Because of this migration, jogs are extinguished and basins stop subsiding as time passes. Fault topography formed by a strike-slip fault has a certain life span, and the life span is in proportion to the size of the topography. Fault topography formed by various sizes of jogs of a strike-slip fault is formed and extinguished in the corresponding time range, and this extinction is repeated in the course of migration of fault traces.     

准噶尔盆地莫西庄地区侏罗系三工河组二段储层特征

利用多种方法对准噶尔盆地莫西庄地区侏罗系三工河组二段储层特征进行了分析。结果表明,其成分成熟度较低、结构成熟度较高,孔隙度主要属特低孔-中孔,渗透率属超低渗-中渗。当孔隙度大于10%时,储层的含油性受渗透率控制。主要孔隙类型为原生粒间孔、溶蚀-改造粒间孔和粒内溶孔,孔隙类别以特大孔为主,而喉道类别以微细喉为主。成岩作用类型主要为机械压实作用、胶结作用、溶蚀和交代作用,成岩阶段处于晚成岩期A亚期,成岩演化过程中,机械压实作用、胶结作用导致储层孔隙度减小约24.5%,同时因溶蚀作用使孔隙度增大约4.5%。     

Spinorial Field and Lyra Geometry

The Dirac field is studied in a Lyra space-time background by means of the classical Schwinger Variational Principle. We obtain the equations of motion, establish the conservation laws, and get a scale relation relating the energy-momentum and spin tensors. Such scale relation is an intrinsic property for matter fields in Lyra background.     

Interaction between caldera collapse and eruptive dynamics during the Campanian Ignimbrite eruption,Phlegraean Fields,Italy

The Campanian Ignimbrite (36000 years B.P.) was produced by the explosive eruption of at least 80 km³ DRE of trachytic ash and pumice which covered most of the southern Italian peninsula and the eastern Mediterranean region. The eruption has been related to the 12-x15-km-diameter caldera located in the Phlegraean Fields, west of Naples. Proximal deposits on the periphery of the Phlegraean Fields comprise the following pyroclastic sequence from base to top: densely welded ignimbrite and lithic-rich breccias (unit A); sintered ignimbrite, low-grade ignimbrite and lithic-rich breccia (unit B); lithic-rich breccia and spatter agglutinate (unit C); and low-grade ignimbrite (unit D). Stratigraphic and componentry data, as well as distribution of accidental lithic types and the composition of pumice clasts of different units, indicate that coarse, lithic-rich breccias were emplaced at different stages during the eruption. Lower breccias are associated with fines-rich ignimbrites and are interpreted as co-ignimbrite lag breccia deposits. The main breccia unit (C) does not grade into a fines-rich ignimbrite, and therefore is interpreted as formed from a distinct lithic-rich flow. Units A and B exhibit a similar pattern of accidental lithic types, indicating that they were erupted from the same area, probably in the E of the caldera. Units C and D display a distinct pattern of lithics indicating expulsion from vent(s) that cut different areas. We suggest that unit C was ejected from several vents during the main stage of caldera collapse. Field relationships between spatter agglutinate and the breccia support the possibility that these deposits were erupted contemporaneously from vents with different eruptive style. The breccia may have resulted from a combination of magmatic and hydrothermal explosive activity that accompanied extensive fracturing and subsidence of the magma-chamber roof. The spatter rags probably derived from sustained and vigorous pyroclastic fountains. We propose that the association lithic-rich breccia and spatter agglutinate records the occurrence of catastrophic piecemeal collapse.