单频GPS整周模糊度动态快速求解的研究   总被引：2，自引：1，他引：2  

刘立龙  刘基余  李光成 《武汉大学学报(信息科学版)》2005,30(10):885-887

提出了一种动态快速求解整周模糊度的方法,即先对系数阵进行QR分解,然后通过矩阵变换使模糊度参数和位置参数分离,从而降低矩阵的维数,满足实时动态求解的要求,最后应用LAMBDA方法搜索模糊度。为验证该算法,用单频GPS接收机进行了静态定位和动态定位两种试验。结果表明,静态定位误差小于1cm,动态定位误差小于3cm。由此可见,该方法能够为动态用户快速而精确地实施GPS单频动态定位。  相似文献   

班公湖—怒江构造带西段三叠纪—侏罗纪构造—沉积演化   总被引：20，自引：2，他引：20  

王冠民  钟建华 《地质论评》2002,48(3):297-303

班公湖－怒江构造带西段在大地构造位置上处于特提斯构造域东端，横跨班公湖－怒江断裂带。三叠纪－株罗纪期间，其构造－沉积演化经历了大陆初始裂谷（T）、原洋裂谷（J1）、残余弧后盆地（J2－J3）阶段。初始裂谷阶段的拉张是呈南断北超的半地堑式由东向西进行的，逐渐形成地堑式原洋裂谷盆地。中晚侏罗世，南部新特提斯洋壳开始北各俯冲,产生的区域挤压应力使原洋裂谷逐渐封闭，裂谷盆地的小洋壳表现出以南向俯冲为主的双向式腑冲，同时伴生区域热沉降，盆地具残余弧后盆地的性质。该阶段,羌南地区发育碳酸盐岩为主的稳定陆缘沉积，冈度斯－念青唐古拉板片北部则形成广泛南超的近源碎屑沉积。  相似文献   

Structural damage detection using the optimal weights of the approximating artificial neural networks     

Shih‐Lin Hung  C. Y. Kao 《地震工程与结构动力学》2002,31(2):217-234

This work presents a novel neural network‐based approach to detect structural damage. The proposed approach comprises two steps. The first step, system identification, involves using neural system identification networks (NSINs) to identify the undamaged and damaged states of a structural system. The partial derivatives of the outputs with respect to the inputs of the NSIN, which identifies the system in a certain undamaged or damaged state, have a negligible variation with different system errors. This loosely defined unique property enables these partial derivatives to quantitatively indicate system damage from the model parameters. The second step, structural damage detection, involves using the neural damage detection network (NDDN) to detect the location and extent of the structural damage. The input to the NDDN is taken as the aforementioned partial derivatives of NSIN, and the output of the NDDN identifies the damage level for each member in the structure. Moreover, SDOF and MDOF examples are presented to demonstrate the feasibility of using the proposed method for damage detection of linear structures. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Optimal design of passive energy dissipation systems based on H∞ and H2 performances     

J. N. Yang  S. Lin  J‐H. Kim  A. K. Agrawal 《地震工程与结构动力学》2002,31(4):921-936

Passive energy dissipation devices (EDDs), such as viscous dampers, viscoelastic dampers, etc., have been used to effectively reduce the dynamic response of civil infrastructures, such as buildings and bridges, subject to earthquakes and strong winds. The design of these passive energy dissipation devices (EDDs) involves the determination of the optimal locations and the corresponding capacities. In this paper, we present two optimal design methodologies for passive EDDs based on active control theories, including H_∞ and H₂ performances, respectively. The optimal design methodologies presented are capable of determining the optimal locations and the corresponding capacities of EDDs. Emphasis is placed on the application of linear matrix inequality (LMI) for the effective design of passive EDDs using the popular MATLAB toolboxes. One important advantage of the proposed approaches is that the computation of the structural response is not needed in the design process. The proposed optimal design methodologies have been applied to: (i) a 10‐storey building and a 24‐storey building both subject to earthquake excitations, and (ii) a 76‐storey wind‐excited benchmark building, to demonstrate the advantages of the proposed design methodologies over the conventional equal capacity design. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

Towards a direct collapse–load method of design for concrete frames subjected to severe ground motions     

M. C. Griffith  A. Kawano  R. F. Warner 《地震工程与结构动力学》2002,31(10):1879-1888

Most current methods of design for concrete structures under earthquake loads rely on highly idealized ‘equivalent’ static representations of the seismic loads and linear‐elastic methods of structural analysis. With the continuing development of non‐linear methods of dynamic analysis for the overload behaviour and collapse of complete concrete structures, a more direct and more accurate design procedure becomes possible which considers conditions at system collapse. This paper describes an evaluation procedure that uses non‐linear dynamic collapse–load analysis together with global safety coefficients. A back‐calibration procedure for evaluating the global safety coefficients is also described. The aim of this paper is to open up discussion of alternative methods of design with improved accuracy which are necessary to move towards a direct collapse–load method of design. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

裂隙型单斜介质中弹性系数的计算及波的传播特性研究   总被引：3，自引：1，他引：3  

王德利  何樵登 《吉林大学学报(地球科学版)》2002,32(2):181-186

根据Hudson等关于裂隙介质弹性系数计算的扰动理论及Bond变换矩阵原理，给出了各向同性介质中含多组垂直裂隙时等效弹性系数的计算方法。计算了含两组斜交的垂直裂隙形成的单斜各向异性介质中的等效弹性系数，并根据Christoffel方程推导、得出水平面内平面波传播的相速度和群速度随方位变化的特性。  相似文献   

An automated strategy for calculation of phase diagram sections and retrieval of rock properties as a function of physical conditions   总被引：9，自引：0，他引：9  

J. A. D. Connolly  K. Petrini 《Journal of Metamorphic Geology》2002,20(7):697-708

We formulate an algorithm for the calculation of stable phase relations of a system with constrained bulk composition as a function of its environmental variables. The basis of this algorithm is the approximate representation of the free energy composition surfaces of solution phases by inscribed polyhedra. This representation leads to discretization of high variance phase fields into a continuous mesh of smaller polygonal fields within which the composition and physical properties of the phases are uniquely determined. The resulting phase diagram sections are useful for understanding the phase relations of complex metamorphic systems and for applications in which it is necessary to establish the variations in rock properties such as density, seismic velocities and volatile‐content through a metamorphic cycle. The algorithm has been implemented within a computer program that is general with respect to both the choice of variables and the number of components and phases possible in a system, and is independent of the structure of the equations of state used to describe the phases of the system.  相似文献   

扎赉诺尔煤田水文地球化学特征及成因分析     

武文  莫若平  孙培城  刘文国 《内蒙古地质》2002,(4)

扎赉诺尔煤田地处山前,有利的地理环境条件形成了独特的水文地质特征—地下水的垂直分带和地下水顺层径流。其特有的水文地球化学环境导致了地下水成分的差异性。本文从水文地球化学的角度,对煤田地下水的水文地球化学特征及成因进行了论述分析。  相似文献   

Gold Occurrence and Ore Genesis,Yata Micro—Disseminated Gold Deposit,Guizhou,Southwest China     

朱笑青  王中刚 《中国地球化学学报》2002,21(4):370-373

The mode of occurrence of gold in the Yata micro-disseminated gold deposit is ap-proached through chemical phase studies coupled with ore-dressing monitoring and micro-beam analysis.The results showed that gold occurred for the most part as ultra-microscopic particles adsorbed on the surfaces or fracture planes of pyrite and other sulphides.The proportions of gold of different occurrences were estimated solutions containing nanometer-sized gold particles were prepared following the hydrolysis-reduction procedure and the adsorption of nanometer-sized gold on ordinary sulphides and rocks was experimentally determined.It is evident that sulphides are good adsorbents of gold and this is consistent with geological observations.  相似文献   

Structure sismique du socle paléozoı̈que du bassin des Doukkala,Môle côtier,Maroc occidental. Indication en faveur de l'existence d'une phase éo-varisqueSeismic structure of the Doukkala basin,Palaeozoic basement,western Morocco: a hint for an Eovariscan fold-and-thrust belt     

Hassan Echarfaoui  Mohamed Hafid  Abdallah Aı̈t Salem 《Comptes Rendus Geoscience》2002,334(1):13-20

Seismic profiles and well data from the Doukkala basin unravel the structure of the Palaeozoic basement and suggest that this coastal zone of western Morocco was affected by a compressive phase during the Frasnian. This resulted in the formation of upright, plurikilometric folds associated with reverse faults (North Doukkala), and of asymmetrical folds associated with mostly west verging ramps (South Doukkala). Folding involved all pre-Upper Frasnian formations and caused partial or total hiatus of Upper Frasnian–Strunian strata. This event can be correlated with the orogenic phase reported from more internal domains of the Morocco Hercynian belt, where it is referred to as the ‘Bretonne’ or ‘Eovariscan’ phase. To cite this article: H. Echarfaoui et al., C. R. Geoscience 334 (2002) 13–20  相似文献