北斗三号系统与GPS定位性能仿真对比分析

为了解北斗三号系统在国内外及南北极地区的定位性能,在STK仿真平台下建立了北斗三号系统30颗星(3GEO、3IGSO和24MEO)的星座模型,对北京、三亚、新加坡、南北极点等11个站点的平均可见星数和几何精度因子GDOP值进行了分析,并与GPS进行了对比。结果表明,北斗三号系统较GPS在国内外及南北极地区典型站点的定位性能更优。     

多维度动态农村土地承包经营权业务权限的设计与实现

为满足浙江省各级农经管理部门在农村土地承包经营权管理系统中复杂的权限管理需要,基于RBAC模型实现了以Apache Shiro安全框架为支撑的多维度动态业务权限管理。该模型从角色维度、部门维度、空间维度、时间维度上分别对用户的资源菜单、工作流、数据操作空间、数据历史回溯4个方面的权限进行细粒度控制。在浙江省农村土地承包管理信息系统中实际运行表明,设计的业务权限系统可满足省市县各级农经管理部门在管理系统的权限要求。     

Hybrids between olive flounder Paralichthys olivaceus and stone flounder Kareius bicoloratus: karyotype, allozyme and RAPD analyses

The hybrid between olive flounder Paralichthys olivaceus and stone flounder Kareius bicoloratus was produced by artificial insemination of olive flounder eggs with stone flounder Sperm. Sinistral and dextral are two types of hybrid progeny after metamorphosis. Karyotypes of both hybrid flounders are the same as those of the two parental species. Of the 22 loci examined from 12 allozymes,12 confirmed hybridization of the paternal and matemal loci in hybrids and no difference was found in allozyme patterns of sinistral and dextral hybrid fishes. RAPD patterns of these specimens were also studied with 38 primers selected from 104 tested. Among them, the PCR products of 30 primers showed hybridization of the paternal and maternal bands. Genetic variation between hybrids and their parental stocks was analyzed by RAPD using 10 of the above 38 primers. The average heterozygosity and genetic distance were calculated. The results suggested that the filial generation could inherit a little more genetic materials from paternal fish than that from maternal fish.     

ETM遥感图像在措勤东部第四系含水性研究中的应用

措勤东部属于极端缺水的地区,利用遥感技术开展第四系松散堆积物含水性调查具有重要作用。本文选用ETM753与8波段融合图像作为遥感解译底图,结合地形地貌、地质和气象影响,建立残积、冲积、洪积、冲洪积、冰川永久积雪、湖积、沼泽和坡积的识别知识体系,划定第四系松散堆积物的高、中、低、差四个含水等级,利用G IS实现第四系松散堆积物及其含水性的高程、坡度和坡向分布,为区内水资源的深入调查提供有力支持。     

矢量图形与影像图像一体化实现

本文在阐述影像金字塔相关理论（构建方法、影像切割等）的基础上,采用VC2005编程实现了在同一GIS系统中进行矢量数据和栅格数据叠加显示的功能模块。该模块可确定是否加载影像,并根据当前矢量图显示范围自动加载不同分辨率的影像图。     

基于PALSAR数据的DEM提取方法研究

针对PALSAR Level 1.1数据,研究使用NASA/JPL提供的开源干涉软件包ROI_PAC Version 3.0提取DEM.ROI_PAC的目前版本只能处理Level 1.0数据,因此,文章在分析了ROI_PAC软件包处理流程的基础上,提出处理Level 1.1数据的方法,并用PALSAR Level 1.1数据对该方法做了验证.干涉重建DEM与参考DEM的对比结果表明,二者的差异均值为0.27 m,标准差为±9.24 m,80%像元点的高程误差在±10 m以内.     

基于线段的基本线/线拓扑关系计算

空间拓扑关系是空间数据建模、空间查询、分析、推理、制图综合、数据质量控制、数据更新等的基础。目前空间拓扑关系研究的主要成果仍然集中在拓扑关系的描述方面,在计算方面的阐述都非常薄弱,不足以指导系统开发人员编程实现。本文研究了IR2中两个简单线目标间拓扑关系的计算方法,重点分析了线/线拓扑关系计算的特点,提出了一种基于线段的线/线拓扑关系计算方法,并用VC＋＋采用底层开发模式实现了基本线/线拓扑关系的计算。     

^234Th作为海洋学中示踪剂的研究进展

^234Th是海洋中日、周、月时间尺度上和颗粒物运动有关的过程的良好示踪剂,常用于海洋碳循环最为重要的区域——真光层中颗粒物的循环,以及和生物中介有关的及一些相对较快发生的海洋过程的研究。^234Th对我们研究由CO2循环导致的全球变暖问题,了解各种元素和化合物在海洋中的分布行为和最终归宿,促进全球质量平衡归宿模型的构建,研究某海域的生物泵与初级和新生产力,促进我们对海洋的进一步了解并引导它健康可持续地为人类所利用等方面有着重要的意义。简要论述了。^234Th作为海洋学中示踪剂的原理和发展过程,比较了目前所使用的各种采样和测量方法,详细介绍了它在垂直通量、颗粒物循环、水平传输和沉积物动力学等方面的应用,并针对目前存在的问题和不足简要归纳了未来研究的方向。到目前为止,^234Th仍然是最快的自然颗粒物活性计时器,而样品处理、分辨率和处理量等方面的进步则推动了。^234Th在海洋学研究中更广泛的应用。开阔大洋中很多^234Th工作都是在JGOFS计划的支持下进行的,因此,^234Th应用的潜在前景可针对JGOFS计划未完成的问题而进行深入研究。     

A preliminary study of variations of the Changjiang Diluted Water between August of 1999 and 2006

A large area hypoxia has been already reported respectively by two interdisciplinary surveys off the Changjiang Estuary since summer of 1999 and 2006. The hypoxic zone shows distinct year-to-year variations. Observed oceanographic data are first analysized and reveal a big difference for the Changjiang Diluted Water (CDW) between these two periods. These great changes are related to the tremendous reduction of the freshwater discharge and variations of wind fields between these two years. It is also found that the monthly mean intrusion of Kuroshio and its branches has increased in the northern East China Sea (ECS), but decreased in the southern ECS in August of 2006 as compared with 1999 on the base of general circulation models. Then, the Regional Ocean Modelling Systems is applied to the East China Sea to evaluate the contributions and relative importance of impacts from the river discharge, wind forcing and open boundary data. Our simulations reproduce the phenomena that more fresh water extends northeastward in 2006 and forms a negative SSS anomaly to the northeast of the river mouth as compared with 1999, which is consistent with observations. The five group numerical tests suggest that the wind forcing dominates the CDW variations followed by the Kuroshio and its branches. The study implies important roles played by hydrodynamic processes on the variability of hypoxic zone in the study areas.     

东海内陆架泥质沉积区全新世古环境变迁:有孔虫证据

对东海内陆架MD06-3040柱状样257个沉积物样品进行了有孔虫及其氧碳稳定同位素分析,应用底栖有孔虫组合和不同生态(表生/内生、内陆架/中外陆架)种的丰度,浮游有孔虫Globigerina.bulloides和Globigeri-noides.ruber的丰度及其稳定同位素记录,探讨了研究区全新世10.6cal.kaBP以来的古环境变迁。分析结果揭示了研究区全新世早期海面快速上升,沉积环境由滨岸内陆架(10.6～9.9cal.kaBP)、内陆架外缘(9.9～8.1cal.kaBP)转变至中陆架并达全新世最高海面(7.7～7.2cal.kaBP)。台湾暖流在8.0cal.kaBP起开始发育,并在6.0～2.8和0.7～0cal.kaBP两个时期派生出明显的上升流。台湾暖流及其所派生的上升流是造成东海陆架泥质快速沉积的最主要原因。采用浮游有孔虫G.bulloides的丰度变化,推测浙闽沿岸流在5.1cal.kaBP之前较弱,之后显著增强,其中在5.1～2.8cal.kaBP时期最为强盛。