静态输出反馈在被动控制设计中的应用     

王刚  姚谦峰 《地震工程与工程振动》2005,25(3):158-162

本文研究了将被动结构控制的参数设计转化为静态输出反馈问题的可能性，以及应用线性矩阵不等式工具求解静态输出反馈问题的方法，最后，给出一个TMD控制的H2-γ次优设计算例。  相似文献   

On tuned mass dampers for reducing the seismic response of structures     

Julio C. Miranda 《地震工程与结构动力学》2005,34(7):847-865

This paper presents an energy‐based theoretical model for a two degree‐of‐freedom mechanical system. After a general formulation in Appendix A, the model is specialized to study tuned mass dampers as a means to substantially increase modal damping in order to induce a consequential decrease of the seismic response of the structures thus provided. Although approximate since it neglects coupling due to damping, it is shown that the model yields a first‐order approximation to the exact frequencies, providing values of optimum damping that closely match exact results proposed by others. In view of this, it is proposed that the model be applied through an iterative numerical procedure that identifies the pertinent optimum parameters. It is also shown that for certain particular benchmark cases the model provides closed‐form equations for the parameters defining the dynamic states related to these special conditions. Despite its approximate nature the model presented in this paper is rational, and due to its explicit consideration of energy balance and overall simplicity, it provides a convenient platform for the study of tuned mass dampers, as well as for other methods of structural passive control. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

松辽盆地南部西部斜坡区晚白垩世坳陷盆地坡折带研究   总被引：3，自引：2，他引：3  

杜江峰  刘招君  董清水  何玉平 《吉林大学学报(地球科学版)》2005,35(2):170-176

通过对晚白垩世松辽盆地南部西部斜坡区的综合研究,从基底构造、古地理位置、地层产状和厚度、钻井和地震资料特征及构造发育情况等方面表明,该区在青山口组-嫩江组坳陷期发育侵蚀坡折带、沉积坡折带和构造坡折带.由于多种类型坡折带的存在,制约着盆地充填可容空间的变化,控制了区内的层序发育、沉积体系展布和非构造圈闭类型.松辽盆地南部西部斜坡区湖盆坡折带附近是非构造油气藏发育的有利部位,可以应用坡折带理论指导本区的隐蔽油气藏勘探.  相似文献   

南沙海域曾母盆地构造样式特征及其与油气聚集和圈闭的关系   总被引：4，自引：1，他引：4  

邱燕 《地质通报》2005,24(1):16-22

南沙海域曾母盆地发育各种类型的构造样式，本文研究与油气聚集和圈闭关系密切的典型构造样式。以盆地构造运动的力学性质为依据，将该盆地的构造样式分为三大类，即伸展构造、挤压构造和走滑构造。伸展构造样式有断块构造和箕状构造；挤压构造样式有褶皱构造、冲断构造和底辟构造；走滑构造样式有花状构造。各种构造样式特征分析结果表明．大部分构造样式可形成能够俘获、圈闭油气的局部构造，部分构造样式除了能形成圈闭以外，其中充填的沉积物还有利于油气的生成一由于这些构造样式的发育时间旱于烃源岩的生烃期和大规模的排烃期，因此极易俘获油气而成为有利的油气聚集带和有效的油气圈闭。  相似文献   

内蒙古东部阿荣旗地区晚白垩世孤山镇组的建立     

孙广瑞  赵焕利  韩彦东  马江水  刘旭光  沙环宇  周世强  马丽玲 《地质通报》2005,24(9):862-866

通过1：25万阿荣旗幅地质调查，在阿荣旗孤山镇-东亚东镇一带发现一套酸-中酸碱性火山岩石组合，时代为晚白垩世，将其新建岩石地层单位——孤山镇组。孤山镇组主要分布于大杨树盆地南部，由流纹岩、流纹质火山碎屑岩、粗面岩和英安岩组成，上覆地层为嫩江组，下伏地层为甘河组。岩石高碱（Na2O＋K2O=7．83％-10．28％），属酸碱性系列。轻稀元素土富集，δEu=0．39-1．07；Nb、Ta基本无亏损，P、Ti强烈亏损，可能形成于陆内断陷盆地活动结束时期。  相似文献   

Emplacement processes and cooling history of layered cyclic unit II-7 from the Lovozero alkaline massif (Kola Peninsula, Russia)     

Olivier Fmnias  Nicolas Coussaert  Stphane Brassinnes  Daniel Demaiffe 《Lithos》2005,83(3-4):371-393

The Lovozero alkaline massif (Kola Peninsula, Russia) is composed of three major units. The central unit (80% of the volume) comprises numerous well developed layers composed, from bottom to roof, of an urtite–juvite–foyaite–lujavrite continuous lithological sequence (ijolite–foid-bearing alkali feldspar syenite in IUGS nomenclature). The mode of emplacement of the massif and the mechanism of formation of the layering are still under debate. Petrological, mineralogical (two stages of crystallisation) and structural evidence from the detailed analysis of one of these layers (unit II-7) is interpreted in terms of both mechanical (magmatic to sub-solidus, non-coaxial deformation) and thermal differentiation operating on a crystal-laden (alkali feldspar, high T nepheline, aegirine-augite) material of foyaitic composition. Textural and mineralogical data suggest that a sheet of foiditic magma intruded into solidified earlier units of the Lovozero layered sequence and acquired a sill-like structure on cooling.  相似文献   

Alkaline Magmatism Versus Collision Tectonics in the Eastern Ghats Belt, India: Constraints from Structural Studies in the Koraput Complex     

Saibal Gupta  Jagatbikas Nanda  Sumit Kumar Mukherjee  Manasij Santra 《Gondwana Research》2005,8(3):403-419

Linear domains of deformed alkaline rocks and carbonatites have recently been identified as representing sites of ancient suture zones. In peninsular India, the western margin of the Proterozoic Eastern Ghats Belt (EGB) is characterized by a series of alkaline plutons that are aligned close to the contact with the Archaean Craton. Most of the complexes were deformed and metamorphosed during a subsequent orogenic event. Unlike other plutons in the belt, the alkaline complex at Koraput reportedly escaped deformation and granulite facies metamorphism forming an anomalous entity within the zone. Multiply-deformed country rocks hosting this complex underwent syn-D_1CR granulite facies metamorphism followed by D_2CR thrusting, with pervasive shearing along a NE-SW trending foliation. A second granulite facies event followed localized D_3CR shearing. Within the Koraput Complex, strain partitioning was responsible for preserving igneous textures in the gabbroic core, but aligned magmatic amphibole needles and plagioclase laths occasionally define a S_1AC fabric. Along the margins, S_1AC is rotated parallel to a NE-trending, east-dipping S_2AC fabric in the gabbro, fringing syenodiorite and nepheline syenite bands. Locally, D_3AC shearing follows D_2AC deformation; S_2AC and S_3AC parallel S_2CR and S_3CR in the country rocks. High-grade metamorphism represented by recrystallization of amphibole and plagioclase, and breakdown of amphibole and biotite to garnet, pyroxene and K-feldspar in the complex follows D_3AC. Unlike earlier reports, therefore, the Koraput body is also deformed and metamorphosed. The aligned alkaline complexes in the EGB probably represent deformed alkaline rocks and carbonatites formed by rifting related to an earlier episode of continental break-up that were deformed during subsequent juxtaposition of the EGB with the Archaean Craton. This supports the contention that the western margin of the EGB and its contact with the Archaean Craton is a suture zone related to the Indo-Antarctica collision event.  相似文献   

Geological constraints on the evolution of the Angolan margin based on reflection and refraction seismic data (ZaïAngo project)     

Maryline Moulin  Daniel Aslanian  Jean-Louis Olivet  Isabelle Contrucci  Luis Matias  Louis Géli  Frauke Klingelhoefer  Hervé Nouzé  Jean-Pierre Réhault  Patrick Unternehr 《Geophysical Journal International》2005,162(3):793-810

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高寒嵩草草甸的被动与主动退化分异特征及其发生机理   总被引：4，自引：1，他引：4  

曹广民  杜岩功  梁东营  王启兰  王长庭 《山地学报》2007,25(6):641-648

高寒嵩草草甸是广布于青藏高原的地带性植被之一,自1980年代以来,发生退化,形成大面积的"黑土型"次生裸地。目前的研究普遍认为,高寒嵩草草甸的退化是由于过度放牧引起的植被演替和啮齿类动物对草场的破坏所致。而本研究认为,随着持续的超载放牧,高寒嵩草草甸的退化过程可以分为异针茅 羊茅-矮嵩草群落、矮嵩草群落、小嵩草群落和杂类草-黑土型次生裸地的四个演替阶段;其经历了异针茅 羊茅-矮嵩草群落向矮嵩草群落植被的被动退化过程和由小嵩草群落向杂类草-黑土型次生裸地的主动退化过程;其发生的动力分别为放牧作用和嵩草特殊的生物学特性(高地下/地上比)引起的草毡表层极度加厚作用。草毡表层的极度加厚,造成土壤水分渗透速率的降低和土壤-牧草之间水分、营养供求的失调,是导致高寒矮嵩草最终退化的根本原因。同时提出高寒嵩草草甸在被动退化阶段,通过降低放牧强度,灭鼠、封育是可以逆转的,而一旦进入主动退化阶段,草皮的塌陷、斑驳,最终形成"黑土滩"型退化草地,这是不可避免的也是不可逆转的。  相似文献   

河流管理中含植物水流问题研究进展   总被引：6，自引：0，他引：6       下载免费PDF全文

唐洪武  闫静  吕升奇 《水科学进展》2007,18(5):785-792

河流管理涵盖灌溉、防洪、河流生态、环境等众多内容,其目的在于保护和恢复河流生态系统的整体生态功能。植物是具有生态功能河流的重要特征,为动物提供了栖息地,是维持河流健康发展的重要因素。由于植物的存在改变了水流运动特性和泥沙及污染物输移规律,含植物水流问题引起了河流管理领域的广泛关注,并且成为河流动力学新的重要的研究课题。回顾了当前国内外河流管理中含植物水流问题研究的主要成果,归纳为水流阻力、紊流结构、泥沙运动和被动标量扩散输移四个方面的研究内容,详细介绍了重要的研究方法、结论和量测手段,讨论了含植物水流问题当前研究存在的不足,并指出今后的研究趋势。  相似文献