The pole of (51) Nemausa

The complex lightcurves make (51) Nemausa a good case for the study of general methods for pole determination. From six lightcurves the pole is determined to 20^h24^m; +53° (1950); the rotation is retrograde with period 7^h.782936 ± 0^h.000005. Presence of nongeometric scattering is proved by a significant 0.008 mag amplitude. Formulae and photometric elements are given for predictions of the shapes of lightcurves in future oppositions. The precision of the Fourier coefficients may be reduced below the present ±0.003 mag level by avoiding the systematic errors in the observations due to phase factor variations and discontinuities when changing comparison stars.     

多波束数据处理中的UTM直角坐标与经纬度坐标转换技术

简要介绍了地图投影的一般概念,重点描述了UTM的优点及其与大地坐标之间的相互转换,该转换方法软件化后形成的技术可以为多波束数据后处理商业软件提供坐标转换的补丁技术。最后附上部分经实际检验的Fortran程序供参考。     

Terrane sutures in the Maine Appalachians,USA and adjacent areas

Terrane sutures in the Maine Appalachians and adjacent areas are recognized as melange dominated, deformed accretionary prisms of Ordovician age, and as a broad synmetamorphic transcurrent fault zone of probable Late Silurian-Early Devonian age. Although the accretionary prisms are associated with present day aeromagnetic and Bouguer gravity anomalies, they are probably not associated with present day crustal penetrating boundaries. The geology of the accretionary prisms indicates subduction-obduction dominated regimes during which (1) the Gander and Boundary Mountain (Dunnage) terranes amalgamated and (2) the composite Boundary Mountain-Gander terrane accreted to the Laurentian margin. The Penobscottian orogeny produced and deformed the older of the two accretionary prisms. This accretionary prism indicates that the Penobscottian was a continuous or perhaps diachronous event which spanned the late Cambrian to early Late Ordovician. The younger accretionary prism was produced and deformed during the Taconian orogeny during late Middle to early Late Ordovician. Initial deformation of this accretionary prism may have overlapped the waning stages of the Penobscottian. Portions of the Taconian arc locally overlie the Penobscottian accretionary prism. A synmetamorphic fault zone lies within Precambrian(?) to Ordovician(?) bimodal metavolcanic and metapelitic rocks assigned here to the Avalon terrane. This zone is several kilometres wide and is interpreted to be the postsubduction suture between the Avalon and Gander terranes, and may, in part, represent a fossil transform fault system. The fault zone contains phyllonites as well as shear zones which generally record dextral motion. The phyllonites were previously interpreted as a stratigraphic unit, whereas the shear zones span or are contained within mappable compositional units. Formation of and movement along these phyllonites and shear zones ceased before the intrusion of Early Devonian plutons. Not all faults in south-western Maine are related to the suture. Younger dip and/or strike-slip and thrust faults are approximately parallel to, or may lie within, the older shear zones and they complicate the recognition of the older faults.     

基于SuperMap的三维虚拟校园设计与实现

本文基于SuperMap软件,以山西师范大学校区为例,通过虚拟地表的生成、三维建模、纹理贴图等方法,打破了时空的限制,直观地展现了交互式三维校园场景,实现了校园三维虚拟场景的缩放、旋转、漫游操作等功能,达到了模拟现实的效果,并可作为数字化校园的基础平台,拓展现实校园的时间和空间维度,提升传统数字校园的运行效率,扩展传统...     

泥质砂岩复电阻率的频散特性实验

不同孔隙流体特性的岩石复电阻率频散实验,是复电阻率测井资料评价水淹层和低阻油层的岩石物理基础。通过水驱水、水驱油、油驱水的岩石复电阻率频散特性的实验研究,发现泥质砂岩的复电阻率频散特性受含油饱和度的影响较大,受地层水矿化度的影响较小,尤其是异相电阻率,受地层水矿化度的影响更小;与含水泥质砂岩相比,含油泥质砂岩的相角相对较大,且随着含油饱和度的增加而增大;含水岩石和含油岩行在频散特性上存在着较大差异。实验研究结果表明,利用基于岩石频散特性发展起来的复电阻率测井技术,可以有效地识别油水层。     

酉阳河流域典型年汛期的基流分割研究

基流分割是水文学研究中的重难点问题之一,目前基流分割也存在许多方法.基于酉阳河典型年汛期实测日平均流量资料,分别采用Chapman-Maxwell改进方程数字滤波法一次滤波(参数N=1)以及二次滤波(参数N=2)、BFI(f)法、HYSEP固定步长法、HYSEP滑动步长法、HYSEP局部最小值法进行基流分割并对其结果进...     

基于层次分析法的大连区域雷灾易损性评价

根据大连地区近6年雷电灾害资料,40年雷暴资料,以大连地理、气候环境为背景,通过计算指标权重,采用层次分析法对大连区域雷灾易损性进行评价,并通过一致性检验。结果显示,金州新区属于极高风险区域,瓦房店属于高风险区域,大连、普兰店、庄河属于低风险区域,旅顺属于极低风险区域。结果表明雷灾区域易损性分析不仅取决于样本区域的自然雷暴日,还与样本区域的经济发展情况、人口密度、历史灾害等多方面因素有关,各指标影响权重也并非相同。采用层次分析法进行区域雷灾评价研究,能够有效减少人为因素,为防雷减灾提供了依据。     

基于CFD的单个建筑物风场模拟参数选择

运用流体力学软件FloEFD对沽源单个建筑物周围的风场进行数值模拟。通过不断改变模型中计算参数的设置进行一系列模拟试验,对比模拟试验结果,并与观测资料进行比较,分析不同计算参数对模拟结果的影响,并获得适用于该模型的最佳参数。主要研究的计算参数包括计算域高度,初始网格等级,局部初始网格等级和不同平均风速剖面形式。结果表明:计算域高度从3倍建筑物高度开始,空腔区的长度、漩涡中心位置以及再发展区的边界位置基本保持稳定。随着初始网格等级的增加,空腔区的长度、再发展区的边界位置及计算时间逐渐增大。局部初始网格等级对模拟结果影响不显著。以两种不同平均风速剖面形式进行模拟,迎风漩涡长度不同,背风面影响不大。与观测资料比较显示,最优参数组合为:计算域高度为3倍建筑物高度,初始网格等级为4、局部初始网格等级为4、平均风速剖面形式为指数律。     

基于对等网络技术的气象数据共享服务应用

气象数据共享业务广泛采用了单一资料源向各个目标节点分发的方式,针对这种共享业务的特点,设计并实现了一种基于对等网络技术的气象数据共享应用,提供资料源的共享发布以及节点间的共享访问功能。该应用通过搭建的仿真平台模拟实际业务应用,验证了在全国气象宽带网络上实现共享传输的可行性。在随后的小范围业务试验中进一步证明了该应用能够在特定的业务场景中不增加中心节点资源消耗而提升数据共享的传输效率。     

车载LiDAR点云中的建筑物特征提取

针对车载LiDAR点云数据处理复杂、时间长的问题,本文以地物不同特征值作为建筑物自动提取算法的依据,通过点云数据预处理、聚类分析等一系列流程最终实现一般建筑物点云的自动提取.通过两个实验区点云数据的提取与相应的实际地物进行精度分析对比,结果表明本文算法对实例测区环境下的不同建筑物点云提取具有较好的有效性,满足数字城市三...