Longitudinal structure of pyroclastic-flow deposits,revealed by GPR survey,at Merapi Volcano,Java, Indonesia     

C. Gomez  F. Lavigne  N. Lespinasse  D.S. Hadmoko  P. Wassmer 《Journal of Volcanology and Geothermal Research》2008

In 2006 Merapi volcano, Indonesia, erupted for a few months, producing several block-and-ash flows reaching a maximum distance of 7.5 km from the main vent. During the eruption, we conducted a survey on those flow deposits in the Gendol Valley at Kaliadem village, about 4.5 km from the Merapi submit, using a Ground Penetrating Radar (GPR). The upper deposit was studied in its distal reaches, whereas the one below was studied in its medial reaches. The field study was carried out with a commercial RAMAC® GPR coupled with 100 MHz antennas, and the data treatment conducted with Reflex™ software. From this survey, we determined both deposits' local (1) thickness – reaching a maximum of 15 m – and (2) internal architecture. This last one is governed by long reflecting horizons extending over 20 to 30 m that delimit layers showing progradation patterns in their distal reaches. Within these layers we could also observe an internal architecture of still unknown origin. The layers are interpreted as the result of the flow pulses that progressively deposited downstream-ward by progradation. However the interpretation of those GPR profiles is a bit hazardous, because of the absence of outcrops, and we can only proceed by analogy with other studies. Nevertheless, despite numerous limitations, GPR is a helpful tool to understand pyroclastic deposits' structure when no visual observations are available.  相似文献   

Impact of acid effluent from Kawah Ijen crater lake on irrigated agricultural soils: Soil chemical processes and plant uptake     

A.M.D. van Rotterdam-Los  A. Heikens  S.P. Vriend  M.J. van Bergen  P.F.M. van Gaans 《Journal of Volcanology and Geothermal Research》2008

Volcanogenic contamination of irrigation water, caused by effluent from the hyperacid Ijen crater lake, has severely affected the properties of agricultural soils in East Java, Indonesia. From a comparison of acidified topsoil with subsoil and with top- and subsoil in a reference area, we identified processes responsible for changes in soil and soil solution chemistry induced by acid irrigation water, with emphasis on the nutrients Ca, Mg, Fe, and Mn, and on Al, which may become phytotoxic under acid conditions in soils. Compositional data for bulk soil composition and selective extractions with 1 M KCl and 0.2 M acid ammonium oxalate are used in a mass balance approach to specify element fluxes, including uptake by rice plants. The results show that input via irrigation water has produced an increase in the total aluminum content in the affected topsoil, which is of the same order of magnitude as the increase in labile Al. High bioavailability of Al, as reflected by concentrations in KCl extracts, is consistent with elevated concentrations observed in rice plants. In contrast, and despite the high input via irrigation water, Ca and Mg concentrations have decreased in all measured soil fractions through dissolution of amorphous phases and minerals, and through competition of Al for adsorption sites on the exchange complex and plant roots. Strong leaching is also evident for Fe and especially Mn. In terms of the overall mass balance of the topsoil, plant uptake of Al, Ca, Fe, Mg and Mn is negligible. If the use of acid irrigation would be stopped and the soil pH were to increase to values above 4.5, the observed phytotoxicity of Al will be halted. However, crops may then become fully dependent on the input from irrigation water or fertilizer for essential elements, due to the previous removal from the topsoil through leaching.  相似文献   

数据库连接池的构建及在JSP中的应用     

周世勇  和晓军 《成都信息工程学院学报》2004,19(1):66-71

分析了几种通过JDBC连接数据库的方法,说明使用数据库连接池的优越性,比较数据库连接池与传统的数据库连接的区别,同时实现了一个数据库连接池的创建以及对这个连接池的使用.  相似文献   

基于Java的审批流程管理设计及实现   总被引：2，自引：1，他引：1  

舒红平  舒灿  蒋建民 《成都信息工程学院学报》2004,19(1):12-17

设计了两种审批流程的设定、申请、审批及归档等功能模块.在Java开发平台上,利用组件技术实现了两种审批流程的管理.  相似文献   

浅析C#和Java的细微差别     

徐家良 《成都信息工程学院学报》2004,19(3):422-429

C#是微软推出的新一代程序语言.对C#与Java的一些容易被忽视的细微的差别进行了讨论.C#设计非常精巧,它的编译器能检查出代码设计过程中一些潜在的错误;而这一点,其它的程序语言要用静态分析工具才能实现.这样程序员就可以专注于设计代码,而不必浪费很多时间来调试难以发现的程序语言陷阱,从而节约了调试时间,缩短了开发周期;同时也提出了在Java中的相应解决方法.相信在不久的将来,新版的Java也可能会增进这些新特性.  相似文献   

网络GIS及其实现方式   总被引：11，自引：0，他引：11  

边馥苓  朱国宾 《测绘工程》1998,7(4):1-6

根据不同的网络体系－局域网、Ｉｎｔｅｒｎｅｔ（ＷＥＢ）网,分别介绍了ＧＩＳ的实现方式以及各自的特点和功能的差异。特别阐述了Ｉｎｔｅｒｎｅｔ（ＷＥＢ）ＧＩＳ的三种实现手段－ＣＧＩ方式、Ｊａｖａ方式及ＣＯＭ／ＤＣＯＭ模型和各自的优缺点。在总结三种网络ＧＩＳ特点后,文章分析指出：ＧＩＳ网络实现方式的不同,从本质上讲是由于其功用不同形成的。  相似文献   

网络地理信息系统(WebGIS)的研究与应用   总被引：1，自引：0，他引：1  

李本新  易增林  万敏 《测绘与空间地理信息》2008,31(2):113-116

网络地理信息系统(WebGIS)是当前GIS技术热点,本文概述了WebGIS的基本特征和基本要求;分析了WebGIS的应用模型、客户端及服务器端的实现,最后引用了一个用Java实现的实例。  相似文献   

长沙市国有土地使用权网上挂牌出让系统建设     

陈刚  范琰  何麒麟 《国土资源信息化》2008,(4):40-43

为促进国土资源信息化工作发展,创新工作模式,提出基于Internet网上进行国有土地使用权出让全自动、全封闭运行,并结合网上银行、CA数字证书和JAVA开发语言,较好的解决了Internet网络环境下挂牌活动的正常进行。  相似文献   

Ubiquitous interactive visualization of 3D mantle convection using a web-portal with Java and Ajax framework     

James B. S. G. Greensky  Wojciech Walter Czech  David A. Yuen  Michael Richard Knox  Megan Rose Damon  Shi Steve Chen  M. Charley Kameyama 《Visual Geosciences》2008,13(1):105-115

We have developed a new strategy and espouse a novel paradigm for large-scale computing and real-time interactive visualization. This philosophy calls for intense interactive sessions for a couple of hours at a time at the expense of storing data on many disk drives during regular or heroic runs on massively parallel systems. We have already carried out successfully real-time volume-rendering visualization by employing hundreds of processors for a grid with over 25 million unknowns. Both Cartesian and spherical 3D mantle convection are visualized. The volume-rendered images are viewed on a large display device, with many panels holding around 13 million pixels. We will employ a software strategy involving an hierarchical rendering service, which will have as software an Ajax interface for interactive visualization of large data sets on many different platforms from desktop PC’s to hand-held devices, such as the OQO and the Nokia N-800. An option for stereo viewing is also implemented. We have installed a user interface as web application, using Java and Ajax framework in order to achieve over the Internet reasonable accessibility to our ongoing runs. Our goal is to expand the array of interactive devices, which will make it feasible to carry out ubiquitous visualization and monitoring of large-scale simulations or onsite events and to allow for collaborations across oceans.  相似文献   

Oceanic Plateau Formation Implied by Ontong Java Plateau,Kerguelen Plateau and Shatsky Rise     

Jinchang Zhang  Yiming Luo  Jie Chen 《中国海洋大学学报(英文版)》2020,19(2):351-360

  相似文献