态矢量方法的实验研究   总被引：5，自引：1，他引：5  

余怀忠  尹祥础  张永仙  夏蒙棼  梁乃刚  李敏  许昭永  彭克银  颜玉定  Wu Zhishen  Qi Li 《地震》2004,24(3):1-7

在地震等灾变的发生之前，会出现一定的前兆现象。中通过实验方法对这些前兆现象之一的态矢量的异常变化进行了研究。实验使用声发射技术(Acoustic Emission)，对三轴应力条件下岩石试件内部微裂纹的产生和扩展进行了记录。实验结果表明在岩石试件最终破坏之前，表征态矢量的相关参量都发生了异常明显的变化，这表明态矢量的异常变化可以被用作为岩石等脆性材料灾变的前兆，使用态矢量方法可以对脆性材料的破坏乃至地震作出预测。  相似文献   

Marine Active Fault Exploration and Paleoearthquake Research   总被引：5，自引：0，他引：5  

Deng Qidong  Chao Hongtai  Min Wei  Zhong Yizhang 《中国地震研究》2002,16(2):155-159

Marine active fault exploration and Paleoearthquake research are still a gap in China.The paper gives a review on major research methods and new progress made abroad,including submarine survey boat.seismic reflection and acoustic reflection.Through detailed studies of offset history of 10 ka to 30ka,it is possible to determine paleoearthquake recurrent intervals and elapsed time since last major earthquake.It is suggested that active fault exploration can be carried out by acoustic exploring method in large earthquake region of Bohai Sea.Paleoearthquake activity history can be revealed and earthquake risk in the future can be predicted.  相似文献   

三轴应力下花岗岩声发射P波Q值的变化   总被引：2，自引：0，他引：2       下载免费PDF全文

缪君  许昭永 《地震地质》1990,12(4):311-315

50×50×100mm3盈江花岗岩样品在σ3=30MPa、σ2=60MPa时增加σ1直至破裂,用波传播和谱振幅比法测定破裂孕育过程中σ3方向和σ2方向声发射P波Q值。结果表明:1.在σ1<0.07σ1P(最大破裂压强)时,σ3、σ2方向都保持高值,在0.2σ1P≤σ1≤0.551P期间,两个方向的Q值呈现出比较平稳的状态,其平均值Q3大约10至20,σ2方向Q2大约20至30。在σ1>0.55σ1P后,σ3方向Q3值起伏增长较大,而σ2方向Q2值仅在σ1>0.7σ1P后,才起伏增长,幅度不如σ3方向大。2.随压力的增加,在σ3、σ2两方向,低频成分明显加大。3.当σ1>0.951P后,出现一种记录畸变现象,对同一源点声发射,从沿同一方向两道记录上看出,早到波形振幅小,而晚到波形其振幅反而大  相似文献   

Geoacoustic inversion using adaptive neuro-fuzzy inference system     

Satyanarayana Yegireddi  Arvind Kumar 《Computational Geosciences》2008,12(4):513-523

The geoacoustic parameters form significant input for underwater acoustic propagation studies and geoacoustic modeling. Conventional inversion techniques commonly used as indirect approach for extraction of geoacoustic parameters from acoustic or seismic data are computationally intensive and time-consuming. In the present study, we have tried to exploit the advantage of soft computing techniques like, reasoning ability of fuzzy logic and learning abilities of neural networks, in inversion studies. The network model based on the combined approach called adaptive neuro-fuzzy inference system (ANFIS), is found to be very promising in inversion of the acoustic data. The network model once built is capable of invert a few thousand data sets instantaneously, to a reasonably good accuracy. In the case of conventional approaches, repetition of the entire inversion process with each new data set is required. A limited number of sensor’s data are sufficient for simulation of the network model and provides an advantage to use short hydrophone array data. Inversion results of a few hundred test data sets, representing different geoacoustic environments, show the prediction error is much less than 0.01 g/cc, 10 m/s, 10 m and 0.1 against first layer’s density, compressional sound speed, thickness and attenuation respectively for a three-layer geoacoustic model. However, the error is relatively large for the second- and third-layer parameters, which need to be improved. The model is efficient, robust and inexpensive.  相似文献   

环南海区域发展特征与一体化经济区建设前景   总被引：2，自引：1，他引：1  

金凤君  姚作林  陈卓 《地理学报》2021,76(2):428-443

《区域全面经济伙伴关系协定》（RCEP）合作框架正催化全球经济版图格局发生剧烈演变,为应对“百年未有之大变局”,中国需要以“一带一路”倡议为契机,以环南海区域为战略基点,在深入研究区域发展特征的基础上,探讨建设“中国+东南亚”战略性一体化经济区的可能性并付诸实施。本文以环南海区域为重点,结合区域发展重点指标描述了其整体发展特征,利用产业结构相似度指数和贸易结构重合度指数,对环南海区域产业与对外贸易的结构性特征进行了剖析,并刻画了环南海区域核心增长区域的空间网络特征,最后讨论了环南海区域构建多元一体化经济区的前景并提出政策建议。结果表明：① 2000—2017年环南海区域主要发展指标增长态势强劲,发展速度和质量远超全球同期平均水平。② 在全球产业转移周期阶段与空间路径的双重驱动下,环南海区域形成了“澳新港—粤闽台文马—滇桂琼泰印菲越—缅老柬”四大梯级发展格局。③ 环南海区域11个国家间产业结构相似度指数和贸易结构重合度指数均处于较高水平,兼具“横向一体化”和“纵向梯级化”复合特征;产业结构与全球贸易商品结构呈现出“高端化”和“低端化”并举的态势。④ 环南海区域已经形成九大核心增长区域,增长极的极化与扩散效应使得不同区域之间的优势产业和出口商品类型呈现相似性和互补性。⑤ 展望未来,新一轮全球产业转移及其引致的全球价值链重组将构建起深度匹配地区资源禀赋特征的区域一体化生产—消费网络,而城市群、高速交通等空间实体所构建的“点—轴”空间网络和“内—外”开放合作政策平台也将更好保障一体化经济区的构建与发展。  相似文献   

Development characteristics and construction prospects for a multi-integrated economic zone in the South China Sea Region     

Jin  Fengjun  Yao  Zuolin  Chen  Zhuo 《地理学报(英文版)》2021,31(3):403-422

The Belt and Road Initiative(BRI)instigated by China is catalyzing the evolution of a new global economic landscape.To cope with the great changes in the economic landscape,China needs to view the South China Sea Region(SCSR)as a strategic focus and study carefully the characteristics of regional development and explore the possibility for construc-tion of a strategic multi-integrated economic zone which includes China and ASEAN countries.Based on key indicators,this paper outlines the overall development characteristics of the SCSR and analyzes the regional structural characteristics of industry and global trade based on the indexes of industrial structure similarity and trade commodity structure coincidence;the paper also depicts the spatial characteristics of the nine core growth areas(CGAs)in the region and discusses the construction prospects for a multi-integrated economic zone in the SCSR.The results show that,first,from 2000 to 2017,the main economic indicators of the SCSR grew quite well,and the development trend was much better than the global average for the same period.Second,driven by the global industrial transfer stages and spatial paths,the level of comprehensive development in the SCSR has evolved into four categories.Third,the index values for industrial structure similarity and trade commodity structure coincidence for the 11 countries in the SCSR have remained at a high level,and reveal an integration trend not only from the horizontal and vertical perspective,but also from an upgrading and downgrading standpoint.Fourth,nine CGAs have been established in the SCSR and the advantaged industries and the export commodity types between different countries exhibited the characteristics of convergence and complementarity due to the polarization and diffusion effects of the CGAs.Finally,from a long-term perspective,the SCSR has already acquired the internal and external conditions such as the 5th global industrial transfer initiative,the reconstruction of the global value chain,regional production-consumption networks and spa-tial entities for building a multi-integrated economic zone in the SCSR.  相似文献   

Embedded technology transfer from an institution and culture nexus perspective: Experiences from the Mombasa-Nairobi Standard-Gauge Railway   总被引：1，自引：1，他引：0  

WANG Jiaoe  DU Fangye  WU Mingquan  LIU Weidong 《地理学报(英文版)》2021,31(5):681-698

Modern railway projects,characterized by"natural monopoly",large investment,and far-reaching influences,are highly dependent on the institutional and cultural environ-ments in China.The countries along the Belt and Road are characterized by weak institutions,unstable politics,and poor technology foundations,which are largely different from China.These factors are severe obstacles to international technology transfer.By summarizing the experiences from the Mombasa-Nairobi Standard-Gauge Railway(SGR)project,this study proposes a framework for embedded technology transfer with a technology-institution-culture nexus.The results indicate that technology localization,including technology standards,management mode,and industrial chain,should be realized in the process of technology transfer.Then,the host government ought to overhaul its institutional and policy framework to support the infrastructure projects.Moreover,the cultural conflicts between the transferor and transferee should be taken seriously.This experience could provide references for other in-ternational infrastructure technology transfers.  相似文献   

Effects of periodic fluctuations of micro‐polar boundary conditions on shear localizations in granular soil–structure interaction     

Babak Ebrahimian  Asadollah Noorzad  Mustafa I. Alsaleh 《国际地质力学数值与分析法杂志》2012,36(7):855-880

In this work, the interface behavior between an infinite extended narrow granular layer and a rough surface of rigid body is investigated numerically, using finite element method in the updated Lagrangian (UL) frame. In this regard, the elasto‐plastic micro‐polar (Cosserat) continuum approach is employed to remove the limitations caused by strain‐softening of materials in the classical continuum. The mechanical properties of cohesionless granular soil are described with Lade's model enhanced by polar terms, including Cosserat rotations, curvatures, and couple stresses. Furthermore, the mean grain diameter as the internal length is incorporated into the constitutive relations accordingly. Here, the evolution and location of shear band, within the granular layer in contact with the rigid body, are mainly focused. In this regard, particular attention is paid to the effects of homogeneous distribution and periodic fluctuation of micro‐polar boundary conditions, prescribed along the interface. Correspondingly, the effects of pressure level, mean grain diameter, and stratified soil are also considered. The finite element results demonstrate that the location and evolution of shear band in the granular soil layer are strongly affected by the non‐uniform micro‐polar boundary conditions, prescribed along the interface. It is found that the shear band is located closer to the boundary with less restriction of grain rotations. Furthermore, the predicted thickness of shear band is larger for higher rotation resistance of soil grains along the interface, larger mean grain diameter, and higher vertical pressure. Regarding the stratified soil, comprising a thin layer with slightly different initial void ratio, the shear band moves towards the layer with initially higher void ratio. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Expression and localization of a novel phosducin-like protein from amphioxus Branchiostoma belcheri     

SAREN Gaowa  ZHAO Yonggang 《中国海洋湖沼学报》2009,27(2)

A full length amphioxus cDNA, encoding a novel phosducin-like protein (Amphi-PhLP),was identified for the first time from the gut cDNA library of Branchiostoma belched. It is comprised of 1 550 bp and an open reading frame (ORF) of 241 amino acids, with a predicted molecular mass of approximately 28 kDa. In situ hybridization histocbemistry revealed a tissue-specific expression pattern of Amphi-PhLP with the high levels in the ovary, and at a lower level in the hind gut and testis, hepatic caecum, gill, endostyle, and epipharyngeal groove, while it was absent in the muscle, neural tube and notochord. In the Chinese Hamster Ovary (CHO) cells transfected with the expression plasmid pEGFP-NIIAmphi-PhLP, the fusion protein was targeted in the cytoplasm of CHO cells, suggesting that Amphi-PhLP is a cytosolic protein. This work may provide a framework for further understanding of the physiological function of Amphi-PhLP in B. belcheri.  相似文献   

Bending localization of nitrous oxide under anharmonicity and Fermi coupling: the dynamical potential approach     

张弛  房超  吴国祯 《海洋学报(英文版)》2010,29(11)

This paper studies the vibrational nonlinear dynamics of nitrous oxide with Fermi coupling between the symmetric stretching and bending coordinates by classical dynamical potential approach. This is a global approach in the sense that the overall dynamics is evidenced by the classical nonlinear variables such as the fixed points and the focus are on a set of levels instead of individual ones. The dynamics of nitrous oxide is demonstrated to be not so much dependent on the excitation energy. Moreover, the localized bending mode is shown to be ubiquitous in all the energy range studied.  相似文献