土与结构相互作用体系振动台模型试验数值模拟研究(英文)

运用土与结构动力相互作用 (SSI)有限元三维分析软件 SASSI2 0 0 0对一个土与结构动力相互作用体系振动台模型试验进行了模拟计算。对振动台模型试验作了简单的介绍 ,并详细叙述了试验的建模方法。对于试验中的刚性地基和柔性地基条件 ,El- centro波、Taft波和 5 0年超越概率为 10 %的南京人工波等三种地震波输入 ,三个加速度峰值水平 0 .1g、0 .2 g、0 .3g及两个水平向地震波输入的各种组合工况均进行了计算。在数值计算中 ,假设地基土为覆盖于基岩上的半无限粘弹性水平成层土 ,采用等效线性模型考虑土的动力非线性的影响 ;上部结构用三维杆系有限元单元模拟 ,楼板用四结点壳单元模拟 ,每个结点有三个平动自由度和三个转动自由度 ,模型试验中所施加的人工质量均匀分布于壳单元上 ;基础视为平板基础 ,用八结点块体单元模拟 ,每个结点有三个平动自由度。将试验结果与计算结果进行对比较 ,结果表明 :计算所建立的模型较好地模拟了相互作用体系在地震荷载下的反应性状 ,计算结果与试验结果吻合较好 ,SSI效应对结构地震反应有很大影响     

中国科学技术协会五届二次全委会明年在京召开我会两名代表参加全会活动

中国科学技术协会五届二次全委会明年在京召开我会两名代表参加全会活动中国科协第五届全国委员会第二次会议将于１９９７年２月２２日至２４日在北京召开。我会副理事长、中国科协全国委员会委员程映雪教授作为正式代表，我会副秘书长、“中国安全科学学报”主编徐德蜀高...     

Adaptive management: Promises and pitfalls

Proponents of the scientific adaptive management approach argue that it increases knowledge acquisition rates, enhances information flow among policy actors, and provides opportunities for creating shared understandings. However, evidence from efforts to implement the approach in New Brunswick, British Columbia, Canada, and the Columbia River Basin indicates that these promises have not been met. The data show that scientific adaptive management relies excessively on the use of linear systems models, discounts nonscientific forms of knowledge, and pays inadequate attention to policy processes that promote the development of shared understandings among diverse stakeholders. To be effective, new adaptive management efforts will need to incorporate knowledge from multiple sources, make use of multiple systems models, and support new forms of cooperation among stakeholders.     

真,假草本咖啡种子的鉴别

在对草本咖啡（Ｃａｓｓｉａｓｏｐｎｅｒａｉｉｎｎ）、望江南（ＣａｓｓｉｓｏｃｃｉｄｅｎｔａｌｉｏＬ．）和决明（ＣａｓｓｉａｔｏｒａＬ．）种子的大小、颜色、形态进行了观察、研究，并对其形态特征进行了解剖学的分析后，提出了鉴别３种种子的方法。     

INTEGRATED RIVER BASIN OPTIMIZATION: MODELING ECONOMIC AND HYDROLOGIC INTERDEPENDENCE1

ABSTRACT: This paper presents an integrated optimal control model that optimizes economic performance of reservoir management in watersheds in which there are significant economic and hydrologic interdependencies. The model is solved using the General Algebraic Modeling System (GAMS). Results show that application of this model to New Mexico's Rio Chama basin can increase total system benefits over historical benefits by exploiting complementarities between hydroelectricity production, instream recreation, and downstream lake recreation.     

MODELING THE BUILDUP AND WASHOFF OF POLLUTANTS ON URBAN WATERSHEDS1

ABSTRACT: A model for urban stormwater quality was developed in this study. The basis for the model is the process by which pollutants build up on the watershed surface. For the wet climate of the study site, it was assumed that there exists an interval of time over which the pollutant buildup equals the pollutant washoff (no accumulation of pollutant). The buildup model was represented by a linear function of the antecedent dry time. The buildup function was then linked with a pollutant washoff model represented by a power function of the storm runoff volume. Various time intervals for no net accumulation were tested to calibrate the model. The model was calibrated to observed data for two small urban basins in Baton Rouge, Louisiana, and model results were used to analyze the behavior of phosphorus concentrations in storm runoff from these basins over a long period of time.     

THE ARMA MODELS APPLIED TO THE FLOW OF KARSTIC SPRINGS1

ABSTRACT: Autoregressive moving average (ABMA) models have been applied to study the flow series of the karstic springs of La Villa, Fuente Mayor (Spain), and Aliou (France). The theoretical meaning of the parameters involved in the model upon applying it to a simplified scheme of the emptying of a karstic aquifer is first analyzed. The types of transformations necessary to apply these models to the flow series that lack normality and have strong periodic components are also indicated, as are the advantages of this type of model and the physical significance of the parameters obtained, with respect to the standpoint of hydraulics, ranging from rather homogeneous aquifers (La Villa) to extremely karstic (Aliou), including aquifers with intermediate characteristics (Fuente Mayor).     

建筑火灾区域模拟竖孔流动的计算

本文根据建筑火灾双层区域模拟思想，给出其常微分控制方程组，并分析了其压力求解方法，然后，运用伯努力利方程推导了相邻房间通过矩形竖孔（门或窗）的质量流率计算公式，还讨论了竖孔流动中性面产生条件。在此基础上，结合一两房间、两孔建筑中烟气运动实例，运用Ｃ．Ｗ．Ｇｅａｒ刚性稳定算法对火灾发展及烟气流动过程进行了数值模拟；给出各竖孔中性面位置、数量和各主环境之间通过竖孔的质量流率；还给出各房间气体平均温升、     

可视化灾害数字仿真重构理论及实证研究(Ⅱ)--理论框架与概念化范式

可视化灾害数字仿真重构理论研究,不仅可以实现对灾害空间数据进行有效的集成管理和时空分析,而且为灾害的防治、应急管理和工程论证等提供可靠的依据,是解决灾害实验的危险性和不可重复性的最佳途径.本文提出可视化灾害数字仿真重构理论的概念、研究对象和方法,综述该理论所需要涉及多种跨学科的技术支持,提出灾害数字仿真重构理论的实施流程,按照致灾因子孕育、发生以及作用于承灾体形成灾害的过程为线索,建立灾害数字仿真模型的概念化范式.上述工作共同构成灾害数字仿真重构的完整理论体系.