地磁1年周期变化的响应函数

用通日月均值减去夜均值计算的月均值资料和Ｓｏｍｐｉ谱分析法分析了１４个台站的北向分量１年周期变化的振幅向相位，时段为１９８４－１９８８年。分析结果显示用Ｐ＾０ｎ（ｄｎｄ＝１，…，６）复合模式的估算的Ｃ值较合理。各台的Ｃ值比较一致。     

Sq外源和内源电流体系的经度效应和UT变化

根据ＩＧＹ／ＩＧＣ期间全球地磁台网以及中国地磁台站的资料，计算出每－ＵＴ小时的Ｓ_ｑ外源和内源电流体系．对Ｓ_ｑ电流体系ＵＴ变化和经度效应的分析研究表明，Ｓ_ｑ外源电流体系的空间图案没有显著的ＵＴ变化，电流涡焦点的地理纬度与磁赤道有密切关系，其变化范围，北半球为２５°－３５°Ｎ，南半球为３０°－４２．５°Ｓ．外源电流总强度的平均值为２２９ｋＡ（北半球）和１７３ｋＡ（南半球），其变化范围为±５０ｋＡ（北半球）和±４０ｋＡ（南半球）．Ｓ_ｑ内源电流体系的图案和强度有显著的ＵＴ变化，电流体系焦点纬度有类似于外源电流系的变化．在大西洋、印度洋、北太平洋地区，内源电流体系的总强度明显小于大陆地区的内源电流强度，表明这些大洋地区上地幔电导率低于大陆地区．     

菲律宾海板块运动欧拉参数的确定及其推论

利用 ＮＵＶＥＬ－１全球板块模型的 １１２２个数据、菲律宾海板块（ＰＨ）的地震滑动 矢量以及由ＧＰＳ测得的的运动速率，根据全球板块模型反演了包括菲律宾海板块在内 的１２个板块相对于太平洋板块（ＰＡ）的欧拉矢量．推得了菲律宾海板块相对周围其他板 块的运动矢量．这一结果与观测值相当符合，并能满足开罗林板块（ＣＲ）附近的ＣＲ－ＰＨ， ＰＡ－ＣＲ边界上的地质及其他地球物理约束．最后利用板块运动参数讨论了菲律宾海板 块的形变．     

陕西地区单台Z／H地磁测深研究

应用陕西地磁台网Ｓｑ资料和单台Ｚ／Ｈ地磁测深法对陕西地区地下电导率分布进行了研究，结果表明，理想代换导体视探ｈ约为５００ＫＭ，电导率σ为０．０７ｓ／ｍ（周期为１２小时），且存在２５０ＫＭ和７００ＫＭ深度附近的高导层，感应比例尺度实部Ｃ＾１ｒｅａｌ和Ｃ＾２ｒｅａｌ及内外场之比│Ｑ＾１│和│Ｑ＾２│似有１１年周期变化。各台测定的结果相当接近，和其他方法测定的范围结果基本一致。用冬夏季静日均值结果较春秋     

ZNC型智能磁力仪Z分量日变形态傅氏拟合误差分析

采用傅氏拟合法对ＺＮＣ型智能磁力仪观测所得每日１４４０个数据进行低通滤波，并对滤波前后的各项结果与量图值进行了分析，结果认为：对于这种高采样率的观测数据，需要进行低通滤波后才能抽取２４个整点值及计算机自动判断极值和极值时间。     

与地磁急始相伴的电离层暂态振荡

分析了从１９８５年９月至１９９２年１２月共１１５次急始型磁暴期间武昌多普勒台阵观测到的电离层暂态振荡（ＳＩＯ）．这种与地磁ＳＣ相伴的ＳＩＯ可分成ＳＣＦ（＋，－），ＳＣＦ（－，＋），ＳＣＦ（＋）与ＳＣＦ（－）几种类型．分析发现，伴随地磁急始在Ｆ区总是存在突发电离层暂态振荡，除非电波被吸收、穿透、被Ｅ５屏蔽，以致Ｆ区无反射回波或在反射区电离密度的高度梯度特别大，使多普勒频率很小在多普勒图上显示不出来．通常ＳＣＦ（＋，－）发生在白天，而ＳＣＦ（－，＋）发生在晚上．ＳＩＯ与地磁急始有很好的对应关系．     

广州地磁台环境干扰的监测与研究

通过对广州地磁台环境干扰源的监测，计算与分析得到：（1）不同时期产生的二个干扰源对地磁台1号墩磁场总强度测值的迭加影响为－25nT，与多台资料对比结果一致。（2）地磁台1号和5 ，1号与干扰源场区外Ⅰ号比测墩测得的磁场总强度、水平强度及垂直强度之差随时间的变化不明显，故认为广州地磁台环境干扰源目前尚属稳定。     

青藏高原雪冰电导率与降水碱度以及大气粉尘载荷变化的关系

对青藏高原小冬克玛底冰川和古里雅冰帽上的数个雪坑和浅冰芯的观测，得 出其碱度（ＯＨ－）剖面、雪坑和冰芯的液态电导率（ＥＣ）变化与ＯＨ－之间呈良好线性相关 （ｒ≥０．８）。分析表明，无论在季节、年际或百年际时间尺度上，ＥＣ与ＯＨ－间的相关性以 及ＥＣ与可溶离子总量（ＴＤＳ）间的相关程度是大致相当的。ＥＣ的波动主要取决于粉尘来 源的碱性盐类（尤其Ｃａ２＋）的变化。因此，ＥＣ参量运用到深冰芯研究中，可反映历史时期 大气粉尘载荷的变化，对反演沙漠演化、大气环流有重要意义。古里雅冰芯记录表明， 大气粉尘的中、长期变化可能取决于气候参量的组合特征：“冷－干”气候阶段粉尘量 上升，ＥＣ和ＯＨ－值高；“暖－湿”阶段粉尘量下降，ＥＣ和ＯＨ－值低。２０世纪初以来，随 着藏北高原气候呈现暖湿化趋势，大气粉尘载荷明显下降。因此，ＥＣ可作为显示大气尘 埃载荷变化的宏观标尺，是气候波动的“指示器”。     

1900—2000年亚洲地磁场长期变化

根据第七代国际地磁参考场（ＩＲＦ）．计算亚洲地区（１０Ｎ—７０Ｎ，４０Ｅ－－１６０Ｅ）各个地磁要素１９００－－２０００年期间（时间间隔为５年）１网格值；绘制相应年代地磁北向分量（Ｘ）、东向分量（Ｙ）和垂直分量（Ｚ）的长期变化分布图；分析地滋长期变化的时空变化特征．     

一种新的地层弹性参数直接反演方法

地震资料反演的目的是估计地层的物理参数（密度、弹性和粘弹性参数）的实际值．本文中将最佳估计值定义为一种参数集,由该参数集可以算出与地震实际资料最佳拟合的合成地震记录．本文提出一种新的地层弹性参数反演方法,主要适用于各向异性介质（横向各向同性介质）中地层弹性参数的反演．本方法不同于过去传统的反演方法,它是一种完全意义上的全波波动方程反演,利用地震勘探中的多波多分量记录（PP反射波记录和PSV转换波记录）联合进行地层弹性参数犆11和犆33反演,用以判断地层的属性．      

Subspace system identification of support‐excited structures—part I: theory and black‐box system identification

This paper reviews the theoretical principles of subspace system identification as applied to the problem of estimating black‐box state‐space models of support‐excited structures (e.g., structures exposed to earthquakes). The work distinguishes itself from past studies by providing readers with a powerful geometric interpretation of subspace operations that relates directly to theoretical structural dynamics. To validate the performance of subspace system identification, a series of experiments are conducted on a multistory steel frame structure exposed to moderate seismic ground motions; structural response data is used off‐line to estimate black‐box state‐space models. Ground motions and structural response measurements are used by the subspace system identification method to derive a complete input–output state‐space model of the steel frame system. The modal parameters of the structure are extracted from the estimated input–output state‐space model. With the use of only structural response data, output‐only state‐space models of the system are also estimated by subspace system identification. The paper concludes with a comparison study of the modal parameters extracted from the input–output and output‐only state‐space models in order to quantify the uncertainties present in modal parameters extracted from output‐only models. Copyright © 2012 John Wiley & Sons, Ltd.     

CAP1400核岛结构缩尺模型对地震反应影响分析

针对核电厂CAP1400核岛结构地震反应问题,构建了核岛屏蔽厂房和辅助厂房整体结构的3个分析模型:原型和1/16、1/40缩尺模型,并在AP000谱和RG1.60谱地震动输入下进行了有限元模拟对比分析,探讨了振动台试验模型缩尺处理的合理性和精确性。研究表明,基于缩尺模型得到的结构自振频率相对于原型结构模型有所降低,降低幅度在8.5%以内;结构模型的缩尺对结构反应峰值加速度和高频（大于3Hz）加速度反应谱的影响较为显著,但对较低频（小于3Hz）的加速度反应谱影响较小;模型缩尺对结构不同方向反应的影响中,刚度越大的方向其影响越大。进一步将结构模型数值模拟结果与1/16缩尺模型的振动台试验结果进行了比较分析,试验给出的结构自振频率远低于模型数值模拟结果,但原型和1/16缩尺模型数值模拟得到的结构反应均与试验结果较为接近。基于模型数值模拟和振动台试验研究,认为对于缩尺比1/16或更大的模型可以忽略模型的缩尺效应。     

Vibration control of cable-stayed bridges—part 1: modeling issues

The objective of the research presented here is to increase the understanding of how the complexities associated with modeling cable-stayed bridges, such as non-linear behaviour and the participation of highly coupled, high-order vibration modes in the overall dynamic response, affect the overall effectiveness of active control schemes. The 316-degree-of-freedom analytical model studied here is based on the Jindo Bridge located in South Korea. Computational considerations associated with control analyses require the size of the model to be significantly reduced, without loss of the important vibration characteristics and complexities. Three separate reduced-order modelling techniques for creating effective control models are studied here: the IRS method, the internal balancing method, and a modal reduction method. These methods are studied and compared on their ability to capture the complex dynamic response of cable-stayed bridges subjected to multiple-support excitation and their ability to create viable and computationally sound state-space models for control analyses. Results show that the modal reduction technique, because of the ability to select only those modes causing the largest force and displacement response, is most effective for control applications. © 1998 John Wiley & Sons, Ltd.     

Time domain analysis of generalized viscoelastic models

This paper examines the convolution integral method for the time domain analysis of viscoelastic models with complex parameters. Such models have been extensively used in soil dynamics and base isolation studies, because they can predict realistically the non-viscous behavior of practical materials such as soil, acrylic polymers, and silicone gels among others. Starting from the constant hysteretic model which was initially proposed to model the behavior of dry sands, it is shown that the basic response functions of complex-parameter viscoelastic models are complex valued functions. The classical relations between the basic response function and the dynamic modulus are extended for the case of these generalized viscoelastic models. Finally, the time domain response of practical constitutive models with complex parameters is investigated, and the limitations and advantages of the convolution integral method are discussed.     

An identification methodology for a class of hysteretic structures

This paper presents a method of identification for determining non-linear dynamic models for certain hysteretic structures. Particular attention is given to modelling and identifying the hysteretic behaviour of structures from strong-motion earthquake data. In this method, the response is separated into mode-like components which are analogous to those of a linear system. Based on modelling of the generalized restoring force of each mode-like component, both non-hysteretic and hysteretic non-linear models are incorporated into the general methodology. A non-hysteretic model provides an initial estimate for a final hysteretic model. The approach is applicable even when data are available from only a small number of locations in the structure. The structural model identified from this method provides a means to predict the response to future events and, ultimately, to examine the damage to a structure as a result of an earthquake.     

湖泊富营养化响应与流域优化调控决策的模型研究进展

湖泊富营养化是全球水环境领域面临的长期挑战,富营养化响应与流域优化决策模型是制定经济和高效调控方案的关键.然而已有的模型研究综述主要集中于模型开发、案例应用、敏感性分析、不确定性分析等单一方面,而缺少针对非线性响应、生态系统长期演变等最新湖泊治理挑战的研究总结.本文对数据驱动的统计模型、因果驱动的机理模型和决策导向的优化模型进行了综述.其中,统计模型包含经典统计、贝叶斯统计和机器学习模型,常用于建立响应关系、时间序列特征分析以及预报预警;机理模型包含流域的水文与污染物输移模拟以及湖泊的水文、水动力、水质、水生态等过程的模拟,用于不同时空尺度的变化过程模拟,其中复杂机理模型的敏感性分析、参数校验、模型不确定性等需要较高的计算成本;优化模型结合机理模型形成“模拟优化”体系,在不确定性条件下衍生出随机、区间优化等多种方法,通过并行计算、简化与替代模型可一定程度上解决计算时间成本的瓶颈.本文识别了湖泊治理面临的挑战,包括:①如何定量表征外源输入的非线性叠加和湖泊氮、磷、藻变化的非均匀性?②如何提高优化调控决策和水质目标的关联与精准性?③如何揭示湖泊生态系统的长期变化轨迹与驱动因素?最后,本文针对这些挑战提出研究展望,主要包括:①基于多源数据融合与机器学习算法以提升湖泊的短期水质预测精度;②以生物量为基础的机理模型与行为驱动的个体模型的升尺度或降尺度耦合以表达多种尺度的物质交互过程;③机器学习算法与机理模型的直接耦合或数据同化以降低模拟误差;④时空尺度各异的多介质模拟模型融合以实现精准和动态的优化调控.     

GEOMORPHOLOGICAL TRANSFER FUNCTION CALCULATED FROM DIGITAL ELEVATION MODELS FOR DISTRIBUTED HYDROLOGICAL MODELLING

Recently, several attempts have been made to relate the hydrological response of a catchment to its morphological and topographical features using different hypotheses to model the effect of the drainage network. Several transfer functions were developed and some of these are based on the theory of a linear model, the geomorphological unit hydrograph. The aim of this paper is to present a methodology to automatically identify the transfer function, using digital elevation models for applications in distributed hydrological modelling. The transfer function proposed herein is based on the Hayami approximation solution of the diffusive wave equation especially adapted for the routing hydrograph through a channel network. The Gardon d’Anduze basin, southern France, was retained for applications. Digital elevation models were used to extract the channel network and divide the basin into subcatchments. Each subcatchment produces, at its own outlet, an impulse response which is routed to the outlet of the whole catchment using the diffusive wave model described by two parameters: celerity and diffusivity functions of geometrical characteristics of the channel network. Firstly, a geomorphological unit hydrograph obtained by routing a homogeneous effective rainfall was compared with the unit hydrograph identified by a lumped model scheme, then the distributed model was applied to take into account the spatial variability of effective rainfall in the catchment. Results show that this new method seems to be adapted for distributed hydrological modelling; it enables identification of a transfer function response for each hydrological unit, here subcatchments, and then simulation of the contribution of each unit to the hydrograph at the outlet. © 1997 by John Wiley & Sons, Ltd.     

A novel framework integrating downhole array data and site response analysis to extract dynamic soil behavior

Seismic site response analysis is commonly used to predict ground response due to local soil effects. An increasing number of downhole arrays are deployed to measure motions at the ground surface and within the soil profile and to provide a check on the accuracy of site response analysis models. Site response analysis models, however, cannot be readily calibrated to match field measurements. A novel inverse analysis framework, self-learning simulations (SelfSim), to integrate site response analysis and field measurements is introduced. This framework uses downhole array measurements to extract the underlying soil behavior and develops a neural network-based constitutive model of the soil. The resulting soil model, used in a site response analysis, provides correct ground response. The extracted cyclic soil behavior can be further enhanced using multiple earthquake events. The performance of the algorithm is successfully demonstrated using synthetically generated downhole array recordings.     

地下结构地震反应的平面计算模型研究

采用平面应变模型对地下结构进行地震反应分析时,其核心问题是中柱的二维等效简化。常用的简化方法是将中柱的材料性质（如弹性模量和密度）进行折减。在此基础上,进一步引入空间约束影响系数和三维还原系数,提出新的中柱二维等效简化方法。针对不同简化方法,分别建立对应的地下结构地震反应分析平面应变模型,计算各模型的地震反应。通过与三维模型计算结果进行对比分析,研究不同简化方法的合理性。计算结果表明,本研究建议的方法可有效提高地下结构平面应变模型的计算精度。