On‐line identification of non‐linear hysteretic structural systems using a variable trace approach

In this paper, an adaptive on‐line parametric identification algorithm based on the variable trace approach is presented for the identification of non‐linear hysteretic structures. At each time step, this recursive least‐square‐based algorithm upgrades the diagonal elements of the adaptation gain matrix by comparing the values of estimated parameters between two consecutive time steps. Such an approach will enforce a smooth convergence of the parameter values, a fast tracking of the parameter changes and will remain adaptive as time progresses. The effectiveness and efficiency of the proposed algorithm is shown by considering the effects of excitation amplitude, of the measurement units, of larger sampling time interval and of measurement noise. The cases of exact‐, under‐, over‐parameterization of the structural model have been analysed. The proposed algorithm is also quite effective in identifying time‐varying structural parameters to simulate cumulative damage in structural systems. Copyright © 2001 John Wiley & Sons, Ltd.     

Digital Surface Development of Large Cylindrical and Conical Structures With a Single-Image Technique

Normally, regular surfaces of architectural or archaeological interest can be accurately mapped with single-image techniques. Whenever possible, such surfaces are developed digitally, or they are presented as suitable cartographic projections. This paper describes the raster development of two large towers, one conical and one cylindrical, with heights of 19m and 12 m, and diameters of approximately 10m and 8m, respectively. The towers, dating from circa 300 BC, are situated on Greek islands and are accessible only on foot. The first tower was imaged from its surrounding hills with several lenses, including powerful telephoto lenses. The other tower was recorded from up to 9m above ground level by means of a modified fishing rod carrying a lightweight 35mm camera. All the non-metric photographs, taken at a negative scale of approximately 1:350 which allowed an overall accuracy of 3 cm to 4 cm to be achieved, were developed digitally and then mosaicked. The raster products are described and discussed.     

云南会泽铅锌矿床构造控矿规律及其隐伏矿预测

对会泽铅锌矿成矿构造体系、构造控矿型式进行研究，认为小江深断裂带和曲靖-昭通隐伏断裂带为矿床形成提供了有利的构造背景，矿床严格受北东向压扭性断裂控制，“阶梯状”和“多字型”构造是矿区具有普遍性的控矿构造型式，北东构造带是主要的成矿构造体系，提出麒麟厂矿床主矿体向南西向侧伏，通过工程验证新增铅锌矿金属储量近100万t。     

Effect of non-linear soil–structure interaction on seismic response of tall slender structures

Some structures may be very massive and may have to be located on relatively soft soil. In such cases, the soil adjacent to the structure behaves in a non-linear fashion and affects the response of the structure to the dynamic loading. An approximate hybrid approach to analyse soil–structure systems accounting for soil non-linearities has been developed in this paper. The approach combines the consistent infinitesimal finite-element cell method (CIFECM) and the finite-element method (FEM). The CIFECM is employed to model the non-linear (near-field) zone of the soil supporting the structure as a series of bounded media. The material properties of the bounded media are selected so that they are compatible with the average effective strains over the whole bounded medium during the excitation. The linear zone of soil away from the foundation, the far-field, is modelled as an unbounded medium using the CIFECM for unbounded media. The structure itself is represented by the FEM. The proposed method is used to model the dynamic response of a one-mass structure and a TV-tower supported on a homogenous stratum and excited by an earthquake. It was found that the secondary soil non-linearity might increase or decrease the base forces of tall slender structures depending on the type of structure, frequency content of the input motion and the dynamic properties of the near-field soil.     

航天飞机成像雷达数据在库车冲断带前缘构造分析中的应用

通过新疆库车县北航天飞机TM和SIR-C/X-SAR图像的处理,利用多参数雷达图像对浅覆盖物下隐伏构造的探测能力,从雷达图像上提取研究区低序次的构造信息,以此分析左行走滑活动相关变形产生的正、负花状构造的地面特征。采用分数维分析方法,研究不同冲积物图像表面的粗糙度特征,确定了库车冲断带前缘在库车县北向西端延伸的位置。显示出多波段多极化成像雷达对新构造的识别能力,从而确定库车冲断带前缘的构造特征。     

二连盆地洪浩尔舒特凹陷下白垩统构造特征与沉积体系研究

在深入研究洪浩尔舒特凹陷大量岩芯、测井和地震资料的基础上，证实这一半地堑相似于北美东部裂谷，而不同于东非裂谷。同时发现边界断层各段位移量最小处为古河流入口地点，后者堆积横向的粗粒三角洲，使断陷被分割成若干次凹，导致构造和沉积的复杂化。断陷中，体系域发育受枢纽断层控制，LST主要分布于下降盘。在等时格架内，进行地震地层学-沉积相分析是掌握储层分布，揭示深部、隐蔽油藏的有力手段。最后判定该凹陷远景在于勘探LST的多种沉积体系。     

青藏高原“亚东-格尔木地学断面”综合地球物理调查与研究

本文概述亚东-格尔木地学断面的地球物理研究成果.在前人工作基础上,沿断面补做了多方法地球物理调查,对原有资料重新解释,综合新、老资料,给出了断面岩石层构造的地球物理解释模型.研究结果认为,青藏高原是一个拼合的增生大陆,是世界上一种新型的俯冲加逆冲叠覆的复杂类型造山带.     

（a0.5,□0.5）BaCe2（CO3 4F矿物晶体结构的测定

( Ca0.5,□0.5）BaCe2（CO3 4F属于六方晶系，晶胞参数为:a=b=5.093(8)A， c=23.017 (6)A， γ=120º, Z= 2。用强功率四回单晶衍射仪在2θ=2 -65º 范围内共收集到821个原始衍射强度数据。晶体结构主要靠重原子法解出，采用空间群P62C,根据344个独立衍射点经多轮最小二乘修正后，获得其全部原子的三维坐标、占位度、各向同性及各向异性温度因子等参数，最终的偏离因子R=0.05.     

桂西蛇场背斜重力滑动构造及控矿作用

印支造山期结束以后,蛇场背斜南翼三叠系在倾斜的基盘上,曾一度象冰川一样在自身重力的作用下,自北向南脱顶滑移,并造成锑的成矿控矿构造。着重叙述了这类构造的发育机制及特征,并探讨其对锑矿床赋存状态的控制作用。