基于Java的系统开发中MVC架构的应用

论述了如何在Java应用开发领域中使用设计模式和MVC(Model-View-Controller)架构。介绍了设计模式的概念和特点,以及MVC架构的设计思想,并分析了MVC架构中包含的几种主要模式,采用MVC架构作为开发的基本架构,可以使开发的项目耦合度降低,提高程序的可扩展性。根据Java应用系统的特点,在实际的“数值预报业务监控系统”的应用开发中如何采用MVC架构提出了一些自己的想法。     

连续观测系统的平差模型与有色噪声补偿

现代测量技术多依赖于各种连续对地观测系统。有色噪声在影响参数估计的同时,还蕴含了地球科学研究所需的大量有用信息。本文讨论了连续平差模型及最小二乘解,将有限维空间中的测量平差问题推广至无穷维空间,从信号分析角度讨论了观测有色噪声的消除方法。研究表明,连续观测方程的最小二乘解可由经典最小二乘解的极限导出;有色噪声对解的影响是系统性的,然而通过合理的观测方案设计可以实现参数的无偏估计     

长江三角洲北翼第一硬土层理化特征及其地质成因

在长江河口两翼广泛分布第一硬土层（FHSL）,研究其形成机制及工程地质特性对工程建设具有很好的指导意义。根据调查资料（钻孔935个,累计进尺42128 m）和试验资料,首次精确确认了长江河口北翼第一硬土层分布界线,研究了第一硬土层的形成年代、粒度特征、地球化学特征、工程地质特性等。研究表明：第一硬土层形成年龄为20 ~ 11 ka B.P.（多个光释光和14C测年资料） ;硬土层含水率随深度的增加有增大的趋势,表明气候自下向上逐渐变凉和变干;第一硬土层的颗粒级配、粒度分布频率曲线、C-M沉积图等特征显示,第一硬土层主要由粉砂、极细砂和粘土粒级组成,样品的粒度频率曲线主要呈单峰分布,反映出物质沉积前所受搬运营力性质单一,土体颗粒沉积以均匀悬浮占绝对优势,沉积环境是一种相对稳定的低能环境。第一硬土层的发育受气候控制,大致可以分为3个阶段：第1阶段(20 ~ 15 ka B.P.)为沉积与成土交替作用时期,且以沉积作用为主,硬土层剖面厚度主要受该阶段控制,至末次盛冰期结束;第2阶段(15 ~ 11 ka B.P.)为暴露成土期,这时洪水不能形成越岸沉积,加积作用基本停止,硬土层厚度不再明显增加,已形成的第一硬土区域受到频繁变迁的分合河网的侵蚀切割,形成多条不规则古河道和台地,硬土层逐渐脱水成陆,经历了风化成壤的过程;第3阶段(11 ka B.P. 至今)为淹埋期,随着全新世的到来,气候变暖,海平面不断上升,硬土层被其上覆的海相沉积层掩埋,成岩作用开始直到现今。土体易溶盐含量较高,为典型氯盐渍土类型,自下而上具有从低变高的趋势,为海相层覆盖硬土层以后成岩过程造成的。     

Transport behavior of nZnO in geosynthetic clay liner used in municipal solid waste landfills under temperature effect

The transport process of nZnO in geosynthetic clay liner (GCL), an anti-seepage material used in municipal solid waste (MSW) landfills, under different seepage temperature conditions was conducted. The transport behavior of nZnO in GCL was analyzed. Results showed that the retardation performance of current GCL used in MSW landfills anti-seepage system against nZnO pollutants was poor. nZnO successfully permeated the GCL and entered external soil–groundwater environment, posing health threats to the life of organisms. Although seepage temperature exerted a small effect on nZnO suspension leakage volume, change in seepage temperature affects the mass of transported nZnO in GCL by redispersion of nZnO in suspension. As the seepage temperature increases, the mass of nZnO that permeated the GCL increases, reaching a maximum at 50 °C, and then decreases.     

A comparative study between China and U.S. on seismic design philosophy and practice of a long span arch bridge

This paper presents the first of a series of case studies on the seismic design of long span bridges （cable-stayed bridges, suspension bridges and arch bridges） under a cooperative research project on seismic behavior and design of highway bridges between the State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University and the Multidisciplinary Center for Earthquake Engineering Research, University at Buffalo. The objective of this series of case studies is to examine the differences and similarities on the seismic design practice of long span bridges in China and the U.S., to identify research needs and to develop design guidelines beneficial to bridge engineers in both countries. Unlike short to medium span bridges, long span bridges are not included in most seismic design specifications, mainly because they are location dependent and structurally unique. In this paper, an available model of a steel tied half through arch bridge with a main span of 550m in China is discussed. Analysis is focused on comparisons of the seismic responses due to different ground motions. Seismic design criteria and seismic performance requirements for long span bridges in both countries were first introduced and compared, and then three near field earthquake records with large vertical components were selected as the excitations to examine the seismic behavior and seismic vulnerability of the bridge. Results show that （1） the selected near field ground motions cause larger responses to key components （critical sections） of the bridge （such as arch rib ends） with a maximum increase of more than twice those caused by the site specific ground motions; （2） piers, longitudinal girders and arch crowns are more vulnerable to vertical motions, especially their axial forces; and （3） large vertical components of near field ground motions may not significantly affect the bridge＇s internal forces provided that their peak acceleration spectra ordinates only appear at periods of less than 0.2s. However, they may have more influence on the longitudinal displacements of sliding bearings due to their large displacement spectra ordinates at the fundamental period of the bridge.     

基于DEM的小流域土地利用分析模型研究与实践

采用DEM数据和各种土地利用类型矢量数据,运用GIS空间分析方法,设计土地利用分析模型,实现各种土地利用类型在不同地形因子影响下的空间分布现状的分析和显示,为区域土地利用规划或优化土地利用结构提供决策服务.     

铁路岩质边坡的RQD研究

以宝成铁路略阳站前后一段铁路工程边坡为例,采用蒙特卡洛原理和方法,计算模拟铁路边结构面概率参数,利用统计结果估算边坡岩体的岩石质量指标ＲＱＤ,提出方向ＲＱＤ的概念,初探方向ＲＱＤ值在铁路工程边坡中的应用及铁路开挖工程活动与自然地质环境间的相互影响。     

关于台风风场研究进展的若干问题探讨

台风是对我国造成严重危害的中尺度天气系统,随着沿海地区经济的发展以及越来越多的海洋开发工程的进行,对台风的研究也日益受到重视。本文从台风的观测、理论和数值研究几个方面综合分析了台风研究中的若干问题,并对现阶段存在的问题进行了讨论。     

安国药材产业发展的经济文化基础*

在区域产业经济发展过程中,地缘优势、经济规律、文化传统都是不容忽视的重要因素。文章以安国市的药材产业为研究实例,通过解释中心集聚的“空间拉力”所孕育的对外交流的潜力,揭示“交易成本机制”在市场交易中的刺激作用,以及分析安国药市网络管理的特定形式,对药材产业区域发展的地理、历史、经济和文化因子作了综合性研究。