空间选址关键因素及其建模研究

影响空间选址的因素错综复杂,本文在对以往一些研究成果进行综合分析的基础上,提出了空间选址的三大影响因素:容量、区位特征和作用范围,并进行了空间选址的建模研究,建立了三个基本模型(容量因素影响模型、区位特征因素影响模型、作用范围因素影响模型)和空间选址的评估模型,并结合应用实例对该模型进行了初步的验证。     

一种渐进加密三角网LIDAR点云滤波的改进算法

传统滤波算法常常是针对某些特定的具有连续表面的区域来进行,带有一定的局限性。这样不能解决对诸如斜坡、密集植被等复杂地区进行真实准确地形提取的难题。本文提出了一种融合区域增长方法的LIDAR点云数据的滤波方法。该方法在对原始点云数据进行预处理的基础上,生成一个松散的TIN,通过迭代生成加密的TIN,其中通过采用两次区域增长的滤波方法,实现原始地形的提取。最后通过对复杂典型数据的对比实验验证了文中所提出的改进方法的有效性和准确性。     

计算机地图制图原理与算法教学方法研究

计算机地图制图足地理信息系统专业的必修课,针对其特点采取恰当的教学方法,能收到事半功倍的教学效果.在教学实践的基础上探索出"三位一体"计算机地图制图教学法,并对其进行研究探讨."三位"是指理论基础、算法实现和应用操作,"一体"是指在正确的教学思想和教学方法指导下,使三者有机地结合起来,相得益彰,达到良好的教学效果.     

应用GAMIT进行高精度GPS基线数据处理

GAMIT是美国麻省理工学院(MIT)与斯克里普斯海洋研究所(S1())研制的一个大型而复杂的GPS数据处理软件,是目前国际上优秀的高精度GPS数据处理通用软件之一.本文主要介绍了GAMIT的数据处理过程和使用方法,并结合实例对GAMIT数据处理结果精度进行了分析.     

Paleoenvironmental implications of the guano phosphatic cementation on Dongdao Island in the South China Sea

The phosphatic cement in the bioclastic sediment sequence on the northeastern shore of Dongdao Island in the South China Sea was studied and its paleoenvironmental implications discussed. Petrological characteristics and major, trace, REE element data unequivocally supported the notion that phosphatization was closely associated with avian guano decomposition and leaching, whereas carbon and oxygen isotope results further revealed that meteoric water were involved in these processes. AMS ¹⁴C dates on the brown phosphate cements indicate that they were formed around 5700, 5000–5100 and 2900 yr BP, respectively. The multi-episodes of phosphatization very likely correspond to intermittent seabird occupation on this island — possibly reflecting Holocene sea-level oscillation and/or long term climate changes in the South China Sea that have controlled seabird habitat. The phosphate cementation, which occurs widely in tropical islands, may be another useful monitor for sea-level and/or paleoclimate changes.     

Temporal and spatial changes of dunes in the Changjiang (Yangtze) estuary,China

The response of subaqueous dunes to the variation of riverine sediment supply in an estuary is rarely reported. Five sets of field measurements of bed sediments and topography were made in the Changjiang estuary, China during dry and flood seasons for the past 9 years. Results show that dunes were mainly three-dimensional (3D) during flood seasons and two-dimensional (2D) dunes during dry seasons. Dunes were also much larger in flood seasons. Dunes mainly occurred within the main channels of the estuary although they extended 11.7 km seaward of their normal extent in the South Channel during dry seasons from 2002 to 2006. This extension of the dune field is likely due to a sharp decline of sediment discharge caused by large reservoirs such as Three Gorges.     

甲烷通量对自生碳酸盐岩和水合物饱和度的影响

为了探讨甲烷通量或SMT对自生碳酸盐岩埋深和水合物饱和度的影响,综述了第六届国际水合物论文集中的相关论文得出如下结论：海底发生富含甲烷的孔隙水渗漏和甲烷气的排出,有利于海底自生碳酸盐岩的沉积;甲烷通量和海底侵蚀可能控制了自生碳酸盐岩和SMT的埋深,然而,甲烷通量或SMT埋深是否控制沉积物中水合物的饱和度目前尚无定论。     

基于DSP TMS320VC5509A图像采集的脱机系统设计与实现

首先介绍了脱机系统的结构,并给出系统中核心芯片DSP TMS320VC5509A与存储芯片EEPROMAT25640的硬件电路设计方案,从该DSP的各种BOOTLOADER方式中分析研究,考虑到烧写速度及电路设计简洁性等因素,采用了SPI EEPROM模式。随后介绍了加载过程中的数据表——BOOT表的概念及生成方式,详细介绍了程序烧写至存储器的过程及软件实现的流程图,最终用一个实例实现系统的脱机运行。     

Summer fast ice evolution off Zhongshan Station,Antarctica

Based on the field data acquired in the program of fast ice observation off Zhongshan Station, Prydz Bay, East Antarctica during the austral summer 2005/ 2006, physical properties evolution of fast ice during the ice ablation season is analyzed in detail. Results show that the annual maximum ice thickness in 2005 occurred in later November, and then ice started to reek, and the ablation duration was 62 days; sea water under the ice became warmer synchronously; corresponding to the warming sea ice temperature, a ＂relative cold mid-layer＂ appeared in sea ice; the fast ice marginal line recoiled back to the shore observably, and the recoil distance was 20.9 km from 18 December 2005 through 14 January 2006. In addition, based on the data of sea ice thickness survey along the investigation course of MV Xuelong on December 18 of 2005, the ice thickness distribution paten in the marginal ice zone have been described ： sea ice thickness increased, but the diversity of floe ice thick-ness decreased from open water to fast ice zone distinctly.     

Outburst risk of barrier lakes in Sichuan,China

34 barrier lakes induced by earthquake have been formed by wedged debris on the river channels after a massive earthquake happening on May 12 in Sichuan, China. Among them, the Tangjiashan Barrier Lake is the largest one. It faces very urgent risk of dam breaking when water level reaches the top and begins overflow in case of storm rainfalls and continually aftershocks, threatening already devastated cities and villages with about 1.5 million people downstream. The outburst of a similar barrier lake occurred in the Minjiang River in 1933, causing a catastrophic flood. Risk analysis indicates that not all barrier lakes are highly dangerous. Only those lakes with very high dams and water to be filled up in short period need to be dealt with immediately.