The second order characteristic condition for plastic flow

In this paper the second order characteristic (discontinuous bifurcation) condition is derived for the granular flow (fully plastic) equations. This second order bifurcation equation is shown to be formally identical to the first order localization requirement during steady elastoplastic deformation provided the elastic compliance tensor is substituted for the product of the plastic multiplier with the flow Hessian. For isotropic yield and flow functions the invariant form of the characteristic condition is given in detail, as well as an alternative expression in adapted co‐ordinates. The characteristic condition can be regarded as defining a hardening function which is maximized to identify the critical angles. When the method is applied to 3D Coulomb flow, Mohr's 3D fracture plane conditions are obtained uniquely. Copyright © 2003 John Wiley & Sons, Ltd.     

△T球体异常的三元解释法

在△Ｔ异常解释课题中，一个新的角度参量─—视磁化特征角的拟定，最大限度地简化了球体磁场表达式。从而才有可能通过特殊解法，给出了球体磁场的极值与拐点公式。作者据此建立了四种不受正常场制约、仅需异常的局部持征曲线即可全面解释三度异常的解释方法。屏障分解、叠加判别、三元迭代的设计，为解释三度体叠加异常给出了简单而易行的途径。     

利用高光谱数据进行植被生化成分反演方法研究

高光谱数据包含着丰富光谱信息,能够定量地分析物质成分^[1]。由高光谱数据,可以运用多元逐步线性回归方法反演植被生化组分含量,从而达到监测植被生长状况的目的^[2]。本文具体介绍了多元逐步线性回归方法,及其在氮、木质素和纤维素含量估算中的应用。     

地理信息系统数据库设计

首先分析了地理信息系统的组成、地理信息系统数据的特征、地理信息系统数据库的功能，然后进行了中心式导航系统数据库的设计，给出了数据库模型的E-R图，最后描述了空间地理信息的查询功能。     

RELAXING ASSUMPTIONS OF PERFECT INFORMATION IN PARK VISITATION MODELS*

Variables related to urban park awareness are identified and methods for relaxing assumptions of perfect information in park use models are discussed. Park awareness is related to park characteristics (age and degree of development of the park), population characteristics (race, age, length of residence, recreation participation), and distance. Park attributes are stronger predictors of both park awareness and use than is distance. These findings parallel similar research on the cognitive aspects of shopping decisions.     

Development and application of a GIS-based tool for earthquake-induced hazard prediction

An integrated GIS-based tool (GTIS) was constructed to estimate site effects related to the earthquake hazards in the Gyeongju area of Korea. To build the GTIS for the study area, intensive site investigations and geotechnical data collections were performed and a walk-over site survey was additionally carried out to acquire surface geo-knowledge data in accordance with the procedure developed to build the GTIS. For practical applications of the GTIS used to estimate the site effects associated with the amplification of ground motion, seismic microzoning maps of the characteristic site period and the mean shear wave velocity to a depth of 30 m were created and presented as a regional synthetic strategy addressing earthquake-induced hazards. Additionally, based on one-dimensional site response analyses, various seismic microzoning maps for short- and mid-period amplification potentials were created for the study area. Case studies of seismic microzonations in the Gyeongju area verified the usefulness of the GTIS for predicting seismic hazards in the region.     

公用微机硬盘信息保护的一种有效方法

介绍一种保护公用微机硬盘信息的有效方法．不仅可以预防各种计算机病毒，更重要的是可以防止人为操作对硬盘信息的破坏。适用于学校等开放性微机实验室的信息安全与保护．     

长江口深水航道数学模型信息系统研究

利用GIS二次开发软件ArcView，完成数学模拟所需的计算网格生成及线边界法中地形数据提取的优化。集成ArcView、Visual Basic及长江口潮流数学模型，实现了数值模拟计算成果的三维可视化及实时互动的动态演示。所开发的长江口数学模型信息系统能根据整治工程需要，提交各类工程数据库。     

地球信息科学的研究与发展

信息时代的召唤,地球信息科学应运而生.经过10a左右的发展,地理信息科学已见雏形.总结了10a来地球信息科学的研究结果,并介绍了地球信息科学的研究内容和发展前景.     

南沙群岛珊瑚礁地貌图像信息管理系统

运用面向对象的软件开发技术,结合珊瑚礁地貌学、计算机图像学和计算机信息管理技术,在Windows平台上研制开发出南沙群岛珊瑚礁地貌图像信息管理系统。该系统集文件管理、数据库管理和图形、图像管理于一体,具有信息检索输出、信息编辑和信息维护等功能,以图形用户介面交互,达到"所见即所得"的效果。