Viscous damping formulation and high frequency motion propagation in non-linear site response analysis

Non-linear time domain site response analysis is widely used in evaluating local soil effects on propagated ground motion. This approach has generally provided good estimates of field behavior at longer periods but has shortcomings at relatively shorter periods. Viscous damping is commonly employed in the equation of motion to capture damping at very small strains and employs an approximation of Rayleigh damping using the first natural mode only. This paper introduces a new formulation for the viscous damping using the full Rayleigh damping. The new formulation represents more accurately wave propagation for soil columns greater than 50 m thick and improves non-linear site response analysis at shorter periods. The proposed formulation allows the use of frequency dependent viscous damping. Several examples, including a field case history at Treasure Island, California, demonstrate the significant improvement in computed surface response using the new formulation.     

皮肤图像分析系统对祛斑类化妆品功效评价的研究

目的是探索如何获得不同色素性皮肤病的清晰图像，研制出操作简单、自动化与精度高的皮肤图像分析系统。方法：应用多光谱皮肤显微偏振光与数字图像处理技术，测量目标皮损形状、面积、灰度、积分光密度及色素颜色参数的变化等。结果：用祛斑类化妆品和药物治疗136例黄褐斑、经该系统测量分析后各治疗组相关参数随时间的推移呈下降趋势，而药物组与对照组相比各参数值明显下降、与各组相比均有显著差异（P＜0．05），并提出客观的疗效评定单位“ID”值。结论：该系统是一种潜力较大的皮肤表面色素定量工具，客观性和重复性好，灵敏度高，不对观察对象造成损伤，在临床获得满意效果。     

Hybrid vibration experiments with a bridge foundation system model

In order to improve seismic design technology of bridges, it is necessary to evaluate the vibration characteristics of a bridge–soil system that consists of soil, foundation structure, pier and superstructure. However, there have been few experimental studies on seismic behavior of bridge–soil system. In this paper, we conducted the hybrid vibration experiment on seismic behavior of bridge–soil system, and examined the applicability of hybrid vibration experiment to study seismic response of bridge–soil system. Based on the experiment results, seismic response of bridge was quantitatively studied.     

Evaluating Earthquake-Triggered Landslide Hazard at the Basin Scale Through Gis in the Upper Sele River Valley

To evaluate techniques for assessing earthquake-triggeredlandslide hazard in the Southern Apennines (Italy), a GIS-based analysis was used to modelseismically induced slope deformations. Geological, geotechnical, geomorphological and seismologicaldata were integrated into a standard earthquake slope stability model. The model assessed thelandslide potential that existed during the 1980 Irpinian earthquake in the Upper Sele river Valley.The standard Newmark displacement analysis, widely used for predicting the location of shallowunstable slopes, does not take into account errors and/or uncertainties in the input parameters.Therefore, a probabilistic Newmark displacement analysis technique has been used. Probabilistictechniques allow, e.g., an estimation of the probability that a slope will exceed a certain criticalvalue of Newmark displacement. In our probabilistic method, a Monte-Carlo based simulation modelis used in conjunction with a GIS. The random variability of geotechnical data is modelled by probabilitydensity functions (pdfs), while for the seismic input three different regression laws wereconsidered. Input probability distributions are sampled and the resulting values input into empiricalrelations for estimating Newmark displacement. The outcome is a map in which to each siteis related a spatial probability distribution for the expected displacement in response to seismic loading.Results of the experiments show a high grade of uncertainty in the application of the Newmarkanalysis both for the deterministic and probabilistic approach in a complex geological setting suchas the high Sele valley, quite common in the Southern Apennines. They show a strong dependence onthe reliability of the spatial data used in input, so that, when the model is used at basin scale,results are strongly influenced by local environmental condition (e.g., topography, lithology, groundwatercondition) and decrease the model performance.     

Optimal placement of dampers and actuators based on stochastic approach

A general method is developed for optimal application of dampers and actuators by installing them at optimal location on seismic-resistant structures. The study includes development of a statistical criterion, formulation of a general optimization problem and establishment of a solution procedure. Numerical analysis of the seismic response in time-history of controlled structures is used to verify the proposed method for optimal device application and to demonstrate the effectiveness of seismic response control with optimal device location. This study shows that the proposed method for the optimal device application is simple and general, and that the optimally applied dampers and actuators are very efficient for seismic response reduction.     

Nonlinear earthquake response analysis and energy calculation for seismic slit shear wall structures

Based on the concept of structural passive control, a new type of slit shear wall, with improved seismic performance when compared to an ordinary solid shear wall, was proposed by the authors in 1996. The idea has been verified by a series of pseudo-static and dynamic tests. In this paper a macro numerical model is developed for the wall element and the energy dissipation device. Then, nonlinear time history analysis is carried out for a 10-story slit shear wall model tested on a shaking table. Furthermore, the seismic input energy and the individual energy dissipated by the components are calculated by a method based on Newmark-β assumptions for this shear wall model, and the advantages of this shear wall are further demonstrated by the calculation results from the viewpoint of energy. Finally, according to the seismic damage criterion on the basis of plastic accumulative energy and maximum response, the optimal analysis is carried out to select design parameters for the energy dissipation device.     

Models of passive margin inversion: implications for the Rhenohercynian fold-and-thrust belt, Belgium and Germany

Positive tectonic inversion is related to the transmission of compressional stresses along a décollement into the foreland of an orogenic zone. This stress and strain concentration in regions remote from the main orogenic front is commonly related to the presence of pre-existing rheological heterogeneities such as normal syn-depositional faults. During inversion, these pre-existing normal faults are reactivated as reverse faults. Tectonic inversion in the Rhenohercynian fold-and-thrust belt during the Variscan Orogeny shows that inversion is likely synchronous with the onset of collision in the hinterland. Here, we present the results of a simplified thermo-mechanical model (STM) which allows one to study strain partitioning between two orogenic zones. We show that, if the two orogenic zones have the same mechanical properties, the viscosity of the décollement, which links them, controls the initial strain partitioning. During subsequent finite shortening, erosional processes determine the partitioning of strain rate. The presence of a weak structure in the inverted zone and of a low-viscosity décollement leads to initial strain concentration in the inverted track rather than in the collision zone and a progressive decrease in strain partitioning between the two orogenic zones. The STM results are in good agreement with results of a 2D finite-element model. We conclude that, in the western part of the Rhenohercynian Massif, simultaneous uplift and deformation within the Mid-German Crystalline Rise (the main collision zone) and the Ardenne Anticlinorium (the inverted zone) lead to interpreting this orogenic event as a case of vice tectonic rather than the propagation of a ‘wave of folding’ towards the Variscan front, as suggested by previous authors.     

河南郑州台数字化DSQ水管倾斜仪观测精度的评定

选取了河南郑州台数字化 DSQ型水管倾斜仪观测资料较好的 2 0 0 1年 10月 1日至 12月 31日的数据进行了分析处理 ,对该仪器的观测精度进行了评定。经计算 ,其北南向和东西向日飘移分别为 0 .0 0 0 7s和 0 .0 0 2 6 s,M2 的振幅因子为 0 .714 9和 0 .6 4 14 ,振幅因子中误差为 0 .0 0 5 5和0 .0 0 4 4。     

GIS支持下的山东省土壤侵蚀空间特征分析

利用遥感（RS）技术提取土壤侵蚀信息，在地理信息系统（GIS）支持下，借助数据库管理系统（DBMS），建立空间数据库和属性数据库；以县级行政区域为综合分析单元，计算土壤侵蚀强度综合评价指数并进行分级处理，对山东省土壤侵蚀空间特征进行分析。     

疏勒河流域昌马灌区泉水量预测分析

疏勒河流域农业灌溉主要采用地表水灌溉 ,泉水为该区农业灌溉的主要水源之一 ,该文利用 2 0世纪 90年代的测流资料 ,采用有限差分方法对疏勒河中游泉水量的变化趋势进行预测分析 ,结果显示 ,随着时间的延长 ,泉流量呈逐渐减小的趋势 ,但下降梯度逐渐变小 ,最终趋于稳定