Wave propagation in a seven-story reinforced concrete building: I. Theoretical models

For transient, high frequency, and pulse like excitation of structures in the near field of strong earthquakes, the classical design approach based on relative response spectrum and mode superposition may not be conservative. For such excitations, it is more natural to use wave propagation methods. In this paper (Part I), we review several two-dimensional wave propagation models of buildings and show results for theoretical dispersion curves computed for these models. We also estimate the parameters of these models that would correspond to a seven-story reinforced concrete building in Van Nuys, California. Ambient vibration tests data for this building imply vertical shear wave velocity β_z=112 m/s and anisotropy factor β_x/β_z=0.55 for NS vibrations, and β_z=88 m/s and β_x/β_z=1 for EW vibrations. The velocity of shear waves propagating through the slabs is estimated to be about 2000 m/s. In the companion paper (Part II), we estimate phase velocities of vertically and horizontally propagating waves between seven pairs of recording points in the building using recorded response to four earthquakes.     

单波高精度测距系统的研究

本文介绍了测距精度优于１０＾－６的自动高精度测距系统的构成、原理及春应用。     

地震灾场的模拟与模拟控制问题研究（Ⅰ）地震灾场模拟

本文将离散事件系统仿真的方法引入到地震工程研究之中．在论述地震灾场模拟与离散事件系统仿真的共性与差异的基础上，以城市地震次生火灾的发生与扑救过程为背景，发展了场、时域复合仿真模型，提出了城市地震灾场的综合模拟算法．实例研究表明，本文建议的地震灾场模拟算法可以揭示复合型工程系统地震反应的一系列特征参数。     

区域持续发展的理论基础—陆地系统科学

对区域持续发展的研究是持续发展深化的必由之路。区域持续发展研究的理论基础是对地球表层自然与人文各种要素的综合规律的揭示，即陆地系统科学。对持续发展广泛深入地研究既是地理科学责无旁贷的任务，也可促进其进一步发展。     

计算机辅助绘制流域等流时线

采用地理信息系统方法，对流域的地形地貌特征进行分析，模拟水质点在流域上的运动轨迹，并根据水质点汇流时间与汇流路径，坡度，坡长的关系，建立了流域汇流等流时线模型，经实例验证，效果较好。     

不同大地坐标系大地坐标求解转换参数模型的应用和权阵的选取

本文介绍了布尔莎(L,B,H)公式求解转换参数模型的应用,重点是讨论权阵的选取。其结果表明,按最小二乘平差求转换参数时,必须使用相关权阵。     

The relations between modulus of elasticity and temperature in the context of the experimental simulation of rock weathering by fire

Fires occur frequently in many biomes and generate high temperatures on the ground surface. There are many field examples of fire causing rock disintegration. The simulation of fire in the laboratory (using a furnace) and the monitoring of changes in rock modulus of elasticity (with a Grindosonic apparatus), reveal that different rocks respond differently to heating. Significant decreases in elasticity occur at temperatures as low as 200°C and granites display particularly marked reductions. Extended periods of heating are not required for significant reductions to occur. It is postulated that the degree of change in elasticity as a result of simulated fire is such that rock outcrops subjected to real fires are likely to be sufficiently modified as to increase their susceptibility to erosion and weathering processes.     

地理专家系统的试验研究

80年代人工智能与地理学的结合产生了地理专家系统(GES)。地理专家系统是继地理信息系统之后,对地理知识与推理形式化,建立的具有一定地理专业水平的计算机软件系统。地理专家系统由地理数据库,地理知识库和地理推理机三大部分组成。地理数据库是GES的数据管理模块,我们设计了一套地理信息系统MCGIS来作为微机地理专家系统MCGES的综合数据库;地理知识库是GES的知识管理模块;地理推理机则是GES的推理控制策略的程序体现。本文结合一个用C语言自行设计的基于规则的产生式微机地理专家系统MCGES阐述了地理专家系统的原理和方法。     

地理信息系统支持下的坡面太阳辐射计算

本文介绍了在地理信息系统(GIS)的空间数据席支持下的区域坡面太阳辐射计算方法。使用该方法,可用计算机按地表实际的地形参数计算山区地表接受太阳总辐射,直接辐射和散射辐射的日、月、年总量,揭示其空间分布规律。这对区域的自然与生态环境研宄具有更要价值。