相图在透闪石和透辉石锦砖配方设计中的应用

文章指出了陶瓷生产中应用相图的要点和设计配方时应注意的问题,并着重从CaO-MgO-Al2O3-SiO2四元系统相图和K2O-Al2O3-SiO2三元系统相图讨论了透闪石和透辉石用于陶瓷锦砖生产中之新体系配方设计的思路。认为纯粹用这两种原料为助熔剂生产锦砖节能效益不十分明显。在传统的锦砖配方中加入适当的透闪石或透辉石可明显地降低产品的烧成温度,但会使坯体的烧成范围变窄。文章强调具有实际意义的配方是具有相当宽烧成范围的低温配方。     

High-resolution magnetostratigraphy and micropalaeontology across the J/K boundary strata at Brodno near ilina, western Slovakia: summary of results

This study summarizes the final results of magnetostratigraphic and micropalaeontological investigations of the Tithonian/Berriasian boundary (J/K) limestones at the locality of Brodno near ilina, Western Carpathians, West Slovakia. The aim is to prepare the background for correlation of a Late Tithonian and Early Berriasian biostratigraphic zonation with global magnetoevents (manifested in detailed magnetostratigraphic profiles) between the Tethyan realm and other regions, particularly the Boreal and Pacific realms. Suitable physical properties of the limestones studied, a favourable geological setting and rich microfossil assemblages (calpionellids) at Brodno (magnetozones M21r to M18r) allowed a systematic collection of new data on the original synoptic section, which now has the character of a high-resolution profile across the J/K boundary. Two reverse subzones detected within magnetozones M20n and M19n are named ‘Kysuca Subzone’ and ‘Brodno Subzone’, respectively. Both can be correlated with analogous subzones in the M-sequence of marine anomalies. Their existence can also be confirmed in the Bosso Valley section in Umbria, central Italy. A detailed study of the interval between magnetozones M20n and M17r in the Bosso Valley profile is presently in its final stage. Both magnetostratigraphic profiles, from the Brodno and Bosso Valley localities, were thoroughly investigated in the intervals close to the J/K boundary and are still unique among continent-based profiles in the detection and precise definition of both reverse subzones within M20n and M19n. Samples collected from the boundary strata of the reverse Kysuca Subzone at Brodno indicated a transition from N (R) to R (N) polarity of the Earth's palaeomagnetic field within a time interval of c. ±5 ka. Limestone samples (total number N=368) were subjected to progressive thermal demagnetization in 10–12 thermal fields and to subsequent multi-component analysis of remanence. The C-component, as the carrier of palaeomagnetic directions, was determined in the temperature interval of 300° to 540°, or possibly 580°C. Magnetomineralogical analyses of pilot samples and unblocking temperatures determined for all samples showed that magnetite is the carrier of remanent magnetization. The positions of the individual events of calpionellid stratigraphy relative to the global magnetic polarity timescale are precisely defined. The base of the Calpionella Standard Zone, which is considered a provisional J/K boundary indicator in ammonite-free sections in the Tethyan realm, lies within magnetozone M19n at the level of 35% of its local thickness. None of the boundaries in the calpionellid zonation coincides precisely with any of those in the palaeomagnetic zonation, but the first appearance ofCalpionella grandalpina , indicating the base of the Intermedia Subzone, lies in close proximity to the base of magnetozone M19r.     

电子地图海量专题要素麻点图技术研究

针对JavaScript成为目前Web电子地图开发的主流技术,而浏览器能承载的数据量和JavaScript的渲染能力有限的问题,该文通过对基于栅格图片的模式和基于插件的矢量数据模式的对比分析后,基于矢量瓦片技术、空间搜索技术和实时渲染技术等关键技术,提出了对海量专题要素进行服务端与客户端协同处理、实时分级渲染的麻点图技术方案,实现了海量专题要素的实时渲染和即时交互,并应用在"天地图·陕西"电子地图系统中。     

基于网络地图服务的MS Office地图插件设计与实现

随着地理信息应用的广泛深入,网络地图服务的嵌入式应用技术研究受到越来越多的重视。MS Office系列软件作为最常用的办公软件平台,具备强大的文字处理功能,但是对地理信息服务的支持有很大不足。用户在Office中表达地理信息一般借助于其他软件并作为图片嵌入文档中。针对这一问题,结合网络地理信息服务技术,研究了基于MS Office软件平台的地图插件设计方案。实现了一个能够在Office软件中直接使用地图服务的第三方Plug-In插件,通过实验验证了该插件的可行性和有效性。     

基于改进Web墨卡托投影的瓦片地图服务设计与实现

为解决网络地理信息应用二、三维一体化显示需要,通常做法是处理并存储两套不同投影的地图瓦片数据,一套采用Web墨卡托投影,面向二维地图应用;一套采用经纬度坐标,面向三维地图应用。这在一定程度上降低数据处理效率、浪费存储资源。文中提出一种改进Web墨卡托地图投影方法,并设计一种面向影像地图和DEM数据的瓦片化方法。方法生成的影像地图瓦片数据既能同时面向二维地图和三维可视化场景使用,又有效解决Web墨卡托投影不支持高纬度地区栅格地图表达的缺陷。将新型的地图投影和数据模型通过瓦片地图服务系统进行验证,证明这种新改进的投影和影像,以及DEM瓦片化方法具备较高的实用性。     

基于云存储的空间信息服务方法

针对如何利用云存储技术提升空间地图瓦片存储与管理的可靠性,突破空间大数据服务与交互操作的瓶颈问题,该文发展了基于Hadoop的地图瓦片服务的基本框架,研究了基于HDFS的地图瓦片存储与访问模型。在GeoServer和OpenLayers开源代码的基础上,实现了基于HDFS的WMTS原型系统,通过实验验证了该方法的可行性;并对比分析了方法的访问性能,验证了该方法的可靠性及可用性。     

基于Flex和ArcGIS Server的WebGIS开发关键技术研究

随着网络技术的飞速发展,高效开发富有表现力的WebGIS应用系统已成为GIS开发的主流。针对传统WebGIS存在表现效果弱、交互性差、响应速度慢等不足,本文通过新一代网络应用RIA(富互联网应用)主流技术Flex与网络应用设计开发方式REST(表述性状态转移)及Arc GIS Server编程接口,解决传统WebGIS的不足,探讨新一代WebGIS应用系统开发中的关键技术问题。     

基于数据缓存的影像数据库的设计与实现

针对影像数据库中数据获取效率低,对系统配置、网络带宽要求高等问题,提出了基于数据缓存的影像数据库管理方式.从体系结构、数据库存储结构以及数据缓存结构3个方面对该方案进行详细说明.实践证明,该方案能够有效地管理海量影像数据,在不影响影像数据共享的前提下,减少了用户与服务器的交互次数,降低了对网络带宽、计算机性能的要求,提高了数据获取的效率.     

Effects of subsurface drainage tiles on streamflow in Iowa agricultural watersheds: Exploratory hydrograph analysis

Flow from artificial subsurface (tile) drainage systems may be contributing to increasing baseflow in Midwestern rivers and increased losses of nitrate‐nitrogen. Standard hydrograph analysis techniques were applied to model simulation output and field monitoring from tile‐drained landscapes to explore how flow from drainage tiles affects stream baseflow and streamflow recession characteristics. DRAINMOD was used to simulate hydrologic response from drained (24 m tile spacing) and undrained agricultural systems. Hydrograph analysis was conducted using programs PART and RECESS. Field monitoring data were obtained from several monitoring sites in Iowa typical of heavily drained and less‐drained regions. Results indicate that flow from tile drainage primarily affects the baseflow portion of a hydrograph, increasing annual baseflow in streams with seasonal increases primarily occurring in the late spring and early summer months. Master recession curves from tile‐drained watersheds appear to be more linear than less‐tiled watersheds although comparative results of the recession index k were inconsistent. Considering the magnitude of non‐point source pollutant loads coming from tile‐drained landscapes, it is critical that more in‐depth research and analysis be done to assess the effects of tile drainage on watershed hydrology if water quality solutions are to be properly evaluated. Copyright © 2008 John Wiley & Sons, Ltd.