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时间分裂空间小波自适应方法在薛定谔方程中的应用
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作者 张然 张凯 《吉林大学学报(理学版)》 CAS CSCD 北大核心 2004年第2期176-178,共3页
将时间分裂空间小波自适应方法应用于数值求解薛定谔方程(普朗克常数ε很小时).为了得到稳定且高精度的数值格式,采用随空间分辨率提高时间步长也自适应的逼近格式,并给出具体的数值例子.
关键词 时间分裂空间 小波自适应方法 薛定谔方程 逼近格式
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分裂空间的一个性质
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作者 李祖泉 《数学杂志》 CSCD 北大核心 1994年第2期285-286,共2页
设x为一个拓扑空间,对于任意的存在可分度量空间M及连续映射f:X→M,使得f(x)=M,A=f ̄-1(f(A)),则x称为分裂空间。本文证明了分裂空间x在广义连续统假设下:(l)若d(X)0≥2”,则d(X)=|x|... 设x为一个拓扑空间,对于任意的存在可分度量空间M及连续映射f:X→M,使得f(x)=M,A=f ̄-1(f(A)),则x称为分裂空间。本文证明了分裂空间x在广义连续统假设下:(l)若d(X)0≥2”,则d(X)=|x|.(2)若(x)≤2”,则对角线集△_x为G_δ集。并且(1)中的条件不能减弱。 展开更多
关键词 分裂空间 拓扑空间 连续映射
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空间分裂:工业资本主义时代空间生产的对抗性特征 被引量:1
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作者 孙江 《苏州大学学报(哲学社会科学版)》 CSSCI 北大核心 2010年第4期15-17,共3页
工业资本主义生产方式的竞争及其分化特性如何借助空间分裂得以实现和巩固是人们理解马克思在其经典巨著《资本论》中对工业资本主义生产方式空间向度论述的盲点。本文从工业城市内部空间分裂、城乡分裂、全球分裂三个层次的空间分裂详... 工业资本主义生产方式的竞争及其分化特性如何借助空间分裂得以实现和巩固是人们理解马克思在其经典巨著《资本论》中对工业资本主义生产方式空间向度论述的盲点。本文从工业城市内部空间分裂、城乡分裂、全球分裂三个层次的空间分裂详细分析工业资本主义生产方式主导的空间生产分裂、对抗特性,以揭示工业资本主义社会存在的空间条件和空间形式,扭转以往人们对工业资本主义生产方式片面的历史认识。 展开更多
关键词 工业资本主义 空间的生产 空间分裂
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灵肉冲突和分裂的世界——曹乃谦小说的矛盾文化内涵 被引量:2
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作者 徐勇 《南都学坛(南阳师范学院人文社会科学学报)》 2009年第5期43-45,共3页
曹乃谦虽然对其笔下的山西雁北世界充满了太多的感情,但这个世界并非被认为的那样是一片"净土",毋宁说这是一个分裂的空间,其时间指向上的暧昧不明使得小说在意义的读解上呈现出多义性的一面,作者把乡土世界简化为食色人生的... 曹乃谦虽然对其笔下的山西雁北世界充满了太多的感情,但这个世界并非被认为的那样是一片"净土",毋宁说这是一个分裂的空间,其时间指向上的暧昧不明使得小说在意义的读解上呈现出多义性的一面,作者把乡土世界简化为食色人生的主题,其实反映的是作者对现实和历史无力把握的心理体验和经验。而其小说在描写食色人生时又呈现出灵肉分离的一面:"我"对灵的注重对应乡土农民对赤裸裸的肉欲的饥渴,这些都透露出作者背后深深的矛盾和焦虑,故此,与其说曹乃谦乃一"真正的乡巴佬",毋宁说他是一个真正的文人,小说世界呈现出的矛盾和分裂其实是作者内心情感体验和思想分裂的表征。 展开更多
关键词 曹乃谦 分裂空间 灵肉分离 文化内涵 重写历史
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M带正交小波的构造 被引量:1
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作者 邸双亮 齐春 梁德群 《工程数学学报》 CSCD 北大核心 2002年第4期86-94,共9页
设{g(x-n):n∈Z}是L2(R)的规范正交系,Fl(z)=∑n∈Zfl(n)z-n,l=0,1,…,M-1,是M个滤波器(M 2),定义l(x)=M∑n∈Zfl(n)g(Mx-n),l=0,1,…,M-1。考虑了在什么条件下,{l(x-n):n∈Z;l=0,…,M-1}构成span{Mg(Mx-n):n∈Z}的规范正交基。给... 设{g(x-n):n∈Z}是L2(R)的规范正交系,Fl(z)=∑n∈Zfl(n)z-n,l=0,1,…,M-1,是M个滤波器(M 2),定义l(x)=M∑n∈Zfl(n)g(Mx-n),l=0,1,…,M-1。考虑了在什么条件下,{l(x-n):n∈Z;l=0,…,M-1}构成span{Mg(Mx-n):n∈Z}的规范正交基。给出了一个定理,该定理描述了与前面所述的"规范正交基底性"相等价的条件。在这些等价性条件的指导下,讨论了M通道的Haar,Shannon,和Meyer滤波器组以及与之相联系的M带正交小波,构造了正交的M带Haar,Shannon,及Meyer小波。 展开更多
关键词 滤波器组 M带正交小波 空间分裂 HAAR小波 SHANNON小波 Meyer小波
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全球化、民族国家与东亚认同 被引量:1
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作者 田毅鹏 《史学集刊》 CSSCI 北大核心 2005年第2期10-12,共3页
近年来,“东亚共同体”问题已经成了东亚各国学术界不同领域热烈讨论的一个共同话题。不仅如此,东亚各国的商界和政界的精英也参加进来,以不同方式鼓动和推进“东亚共同体”的构建。东亚各国经济上相互依赖的加深固然给“东亚共同体”... 近年来,“东亚共同体”问题已经成了东亚各国学术界不同领域热烈讨论的一个共同话题。不仅如此,东亚各国的商界和政界的精英也参加进来,以不同方式鼓动和推进“东亚共同体”的构建。东亚各国经济上相互依赖的加深固然给“东亚共同体”的构建提供了有利条件,但不可否认,对迅速发展变化的东亚地区前景的担忧,是许多人鼓吹“共同体”意识的另外一种重要推动力量。经过千百年的演进,东亚似乎正处于一个十字路口:是像现在欧洲国家一样,超越民族国家的界限,形成一种新的共同体?还是要重蹈欧洲国家的旧日覆辙,在融成共同体之前也来一番你死我活的较量?无疑,对东亚历史的再认识是我们思考这一问题的起点。目前东亚国家不仅生活在现实里,也徘徊在历史中。东亚国家间关系中时隐时现的矛盾和问题,无不与历史的纠葛纠缠在一起。人们不仅要问:我们构建“东亚共同体”的历史基础有多少?或者说历史能给“东亚共同体”的构建带来什么?正是为了解读这些问题,我们组织了这个专栏。应邀参加本专栏讨论的作者有在国际学术界声明显赫的“学界泰斗”,也有初出茅庐的青年学子。尽管他们的地位和视角不同,观点差异很大,但思考的主线都是“东亚共同体”的历史经验问题,每一篇文章都不乏予读者以启迪的真知灼见。我们相信这组文章? 展开更多
关键词 全球化 民族国家 东亚认同 区域统合 区域“空间分裂 区域认同
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Adaptive Spatial-division Split-step Fourier Migration Method
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作者 赵景霞 张叔伦 +1 位作者 王昌龙 倪逸 《Applied Geophysics》 SCIE CSCD 2005年第2期75-79,i0001,共6页
This paper presents a new depth migration method, adaptive spatial-division split-step Fourier (ASDSSF) migration. In this method we introduce the idea of a stratified phase shift migration into the split-step Fouri... This paper presents a new depth migration method, adaptive spatial-division split-step Fourier (ASDSSF) migration. In this method we introduce the idea of a stratified phase shift migration into the split-step Fourier (SSF) migration to make an accurate and efficient wave field image when sharp discontinuities appear in the velocity field. In principle, the ASDSSF migration is a multi-reference slowness (reciprocal of velocity) (MRS) migration. Compared to previous MRS migration methods, this method uses fewer reference slowness values without accuracy loss. The reference slowness is determined in this paper according to an error-control parameter of the perturbation term in the SSF operator and the variation of the complet velocity field. The velocity corresponded to reference slowness can define a spatial division. Each division can also be divided into several discontinuous spatial subdivisions to effectively reduce the number of reference slowness values needed. The choice of reference slowness, including the number of reference slowness values needed and how to construct the spatial divisions, is adaptive and reasonable at each extrapolation step (depth step). A simple and economical smoothing filter in the wave number-frequency domain is designed to avoid artifacts in the wave field extrapolation due to the presence of sharp discontinuities in the velocity field. For comparable conditions the present approach to migration is expected to be computationally more efficient and accurate than other MRS migration methods. The performance of the method is demonstrated on a simple 2D prestack model and the prestack SEG/EAEG salt dataset. 展开更多
关键词 MIGRATION spatial-division multi reference slowness ADAPTIVE and sharp discontinuity
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The spatial distribution characteristics of shallow fissures of a landslide in the Wenchuan earthquake area 被引量:1
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作者 XU Xing-qian 《Journal of Mountain Science》 SCIE CSCD 2016年第9期1544-1557,共14页
Shallow fissures, being the main infiltration paths of fluid on the surface of a slope, played an important role in the whole process of a landslide. However, the spatial distribution characteristics of fissures in th... Shallow fissures, being the main infiltration paths of fluid on the surface of a slope, played an important role in the whole process of a landslide. However, the spatial distribution characteristics of fissures in the slope are difficult to be determined. In this study, we attempted to characterize the variation pattern of slope fissures along depth in the Wenchuan earthquake area in Sichuan Province by combining engineering geological investigation, geomorphologic analysis and geophysical investigation. The geophysical methods that were used in this study include Multichannel Analysis of Surface Wave(MASW), Ground Penetrating Radar(GPR) and Electrical Resistivity Tomography(ERT). The results suggested that geophysical parameters(shear wave velocity, electromagnetic signals attenuation and resistivity) could provide valuable information for the spatial network of shallow fissures. Through the verification by engineering geological survey and geophysical sensitivity analysis, this work highlighted that MASW was the most appropriate technique to delineate the propagation of shallow fissures in a gravel soil slope. 展开更多
关键词 Shallow fissures LANDSLIDE Wenchuanearthquake Geophysical prospecting
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Analysis of Dynamic Variations of Crustal Density in the Longmenshan Area before the Wenchuan M_S8.0 Earthquake
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作者 Li Yuan Niu Anfu +1 位作者 Liu Xikang Zhao Jing 《Earthquake Research in China》 CSCD 2015年第3期303-318,共16页
Based on the repeated gravity observation data from 1996 to 2007 from the Longmenshan gravity network, which has been dealt with by adjustment processing, the benchmark interference removal and impact of elevation cha... Based on the repeated gravity observation data from 1996 to 2007 from the Longmenshan gravity network, which has been dealt with by adjustment processing, the benchmark interference removal and impact of elevation changes removal, and by using the 3-D inversion method to reflect underground density, we analyze the characteristics of Longmenshan regional dynamic crustal density at depths of 25km, 20km and 15kin. The results show that in the Wenchuan earthquake preparation process, the regional density field showed marked characteristics both in time and space distribution. From the point of time process, the density change trend in the ten years before the earthquake presents a periodic change pattern: steady phase, dramatic stage, slow reducing phase and slow increase phase. The degree of density changes is from large to small, which means that earthquake gestation has reached the final stage. From the point of space distribution, density change distribution has a tendency of "dispersion--relative concentration", this shows that before the earthquake, the entropy of the underground density field was decreased. In addition, dramatic density changes often occur in the Longmenshan fault zone and western Sichuan plateau. Also, with the increase of depth, the trend of density change is more and more obvious. Through comparative analysis, the influence of density change on gravity is much bigger than that from height change. 展开更多
关键词 3-D inversion Dynamic change of density Wenchuan earthquakeLongmenshan fault zone The influence factors of gravity
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On Shear Wave Splitting in the Zhangjiakou-Bohai Sea Seismic Belt
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作者 Sun Jin Shi Yutao +1 位作者 Zhao Bo Gao Yuan 《Earthquake Research in China》 2014年第2期200-209,共10页
The Zhangjiakou-Bohai Sea seismic belt is an important seismic zone in North China. The direction of principal compressive stress is near EW in this region. According to digital seismic data from the Capital Region fr... The Zhangjiakou-Bohai Sea seismic belt is an important seismic zone in North China. The direction of principal compressive stress is near EW in this region. According to digital seismic data from the Capital Region from September 2005 to September 2010,and using the SAM method,the spatial distribution of the crust anisotropy characteristics are studied and discussed in the middle-eastern part of the Zhangjiakou-Bohai Sea seismic belt. The principal polarization direction,which is near EW direction,is obvious in the middleeastern Zhangjiakou-Bohai Sea seismic belt. The spatial distribution of polarization direction crossing the Zhangjiakou-Bohai Sea seismic belt shows that there is little difference among the Yanshan uplift area,inside of the seismic zone and North China basin,and the principal polarization direction is near EW. 展开更多
关键词 Crustal anisotropy Shear-wave splitting POLARIZATION Time delay The Zhangjiakou-Bohai Sea seismic belt
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Characterization of the Crustal Thickness and Poisson's Ratio of the Binchuan Region
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作者 Deng Jiamei Jin Mingpei +4 位作者 Chen Jia Gao Qiong Zhang Huaying Wang Jun Ye Beng 《Earthquake Research in China》 CSCD 2017年第1期79-89,共11页
This paper presents the changes of crust thickness and Poisson's ratios distribution in the Binchuan region, where the first air-gun transmitting station and it's a small dense array were deployed. From September 20... This paper presents the changes of crust thickness and Poisson's ratios distribution in the Binchuan region, where the first air-gun transmitting station and it's a small dense array were deployed. From September 2011 to January 2014, more than 239 teleseismic events of M≥ 6.0 were recorded in 16 stations in the Binchuan region. Their P-wave receiver functions were analyzed respectively. The high spatial resolution result shows that the average crust thickness of Binchuan region is 45.3km, it follows the rule of "deeper in the north and east part, shallower in the south and west part. " The deepest region is in Xiaoyindian Station; the crust thickness is 47.9km; the shallowest region is in Paiying Station, it has the thickness of 42. lkm. It shows that the deeper Moho surface nearby the Chenghai fault and shallower nearby the Honghe fault; the isoline distribution of thickness changes greatly nearby the Chenghai fault and slowly nearby the Honghe fault. From the distribution of Poisson's ratios, it is unevenly in the study area with a great difference from the north part to the south part, which shows a characteristic of "lower in the north, higher in the south". The Poisson's ratio nearby the Honghe fault is medium too high ( 0. 26 ≤ σ≤0. 29 ) ; lower nearby the Chenghai fault ( ≤0. 26). This paper concludes the possible reason of different characteristic between Poisson's ratio and crust thickness is thicker in the upper crust in the Binchuan region. 展开更多
关键词 Crustal thickness Poisson's ratio Receiver function The Binchuan region
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Study on Potential Strong Earthquake Risks Around the Mabian Area,Southern Sichuan
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作者 Yi Guixi Wen Xueze +3 位作者 Zhang Zhiwei Long Feng Ruan Xiang Du Fang 《Earthquake Research in China》 2010年第4期478-490,共13页
Based on seismic data from the regional network for the last 34 years, we analyzed the present fault behavior of major fault zones around the Mabian area, southern Sichuan, and identified the risky fault-segments for ... Based on seismic data from the regional network for the last 34 years, we analyzed the present fault behavior of major fault zones around the Mabian area, southern Sichuan, and identified the risky fault-segments for potential future. The method of analysis is a combination of activity background of historical strong earthquakes mainly show ~ ( 1 ) The spatial distribution of b-values strong and large earthquakes in the spatial distribution of b-values with and current seismicity. Our results indicates significant heterogeneity in the studied area, which reflects the spatial difference of cumulative stress levels along various fault zones and segments. (2) Three anomalously low b-value areas with different dimensions were identified along the Mabian-Yanjin fault zone. These anomalies can be asperities under relatively high cumulated stress levels. Two asperities are located in the north of Mabian county, in Lidian town in western Muchuan county, and near Yanjin at the south end of the fault zone. These two areas represent potential large earthquake seismogenic sites around the Mabian area in the near future. Besides them, the third relatively smaller asperity is identified at southern Suijiang, as another potential strong- earthquake source. (3) An asperity along the southwestern segment of the Longquanshan fault zone indicates the site of potential moderate-to-strong earthquakes. (4) The asperity along the segment between Huangmu town in Hanyuan county and Longchi town in Emeishan city on Jinkouhe-Meigu fault has potential for a moderate-strong earthquake. 展开更多
关键词 Spatial distribution of b-values ASPERITIES Mabian area Strong earthquake risk
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Numerical simulation of the segmentation of the stress state of the Anninghe-Zemuhe-Xiaojiang faults 被引量:8
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作者 ZHU AiYu ZHANG DongNing JIANG ChangSheng 《Science China Earth Sciences》 SCIE EI CAS CSCD 2016年第2期384-396,共13页
We established a three-dimensional finite element model of the Anninghe-Zemuhe-Xiaojiang faults region using contact surfaces of different sizes to describe the spatial segmentation characteristics of the faults. Our ... We established a three-dimensional finite element model of the Anninghe-Zemuhe-Xiaojiang faults region using contact surfaces of different sizes to describe the spatial segmentation characteristics of the faults. Our model is based on constraints from GPS observations, models of the crust and upper mantle, precise earthquake locations, the tectonic stress field, the slip rate of the faults, and the rheology of the lithosphere in the Sichuan-Yunnan area. Considering the influence of strong earthquakes since A.D. 1327, we analyzed the main controlling factors of the characteristics of the strong earthquakes and also studied by numerical simulation the possible areas of future earthquake risk and their relationship with tectonic stress. The numerical results showed that the gravitational potential energy of the Qinghai-Tibet Plateau and the interaction of adjacent blocks are the main kinetic factors affecting the characteristics of the tectonic stress distribution. There appears to be some correspondence between the distribution of tectonic stress and the b value; however, we also found that some low b value locations correspond to regions of lower stress. This contradiction may be the result of some comprehensive factors, such as the release of strain energy caused by strong earthquakes. 展开更多
关键词 Anninghe-Zemuhe-Xiaojiang faults Stress state Gravitational potential energy b value Numerical simulation
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Remote Gully Erosion Mapping Using ASTER Data and Geomorphologic Analysis in the Main Ethiopian Rift 被引量:3
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作者 Moncef Bouaziz Arief Wijaya Richard Gloaguen 《Geo-Spatial Information Science》 2011年第4期246-254,共9页
The Main Ethiopian Rift(MER)is an area of extreme topography underlain by post-Miocene volcanic rocks,Jurassic limestone and a Precambrian basement.A prime concern is the rapid expansion of wide gullies that are impin... The Main Ethiopian Rift(MER)is an area of extreme topography underlain by post-Miocene volcanic rocks,Jurassic limestone and a Precambrian basement.A prime concern is the rapid expansion of wide gullies that are impinging on agricultural land.We investigate the potential contribution of Advanced Space-borne Thermal Emission and Reflection Radiometer(ASTER)data and geomorphologic parameters to discern patterns and features of gully erosion in the MER.Maximum Likelihood Classifica-tion(MLC),Support Vector Machine(SVM),and Minimum Distance(MD)classifiers are used to extract different gully shapes and patterns.Several spatial textures based on Grey Level Co-occurrence Matrices(GLCMs)are then generated.Afterwards,the same classifiers are applied to the ASTER data combined with the spatial texture information.We used geomorphologic parameters ex-tracted from SRTM and ASTER DEMs to describe the geomorphologic setting and the gullies' shapes.The classifications show accuracies varying between 67% and 89%.Maps derived from this quantitative analysis allow the monitoring and mapping of land degradation as a direct result of gully-widening.This study reveals the utility of combining ASTER data and spatial textural infor-mation in discerning areas affected by gully erosion. 展开更多
关键词 remote sensing gully erosion TEXTURE ASTER data
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Crack status analysis for concrete dams based on measured entropy 被引量:3
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作者 WU Bang Bin WU Zhong Ru +3 位作者 CHEN Bo SU Huai Zhi BAO Teng Fei WANG Shao Wei 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2016年第5期777-782,共6页
The integrity and safety of concrete darns are seriously affected by the existing cracks in dam bodies, and some serious cracks may cause dam failure or disaster. The propagation of cracks in concrete dams is accompan... The integrity and safety of concrete darns are seriously affected by the existing cracks in dam bodies, and some serious cracks may cause dam failure or disaster. The propagation of cracks in concrete dams is accompanied by changes in energy distribution, which can be represented by changes in the structure's system entropy. Therefore, the entropy theory can be used in analyzing the behavior of dam cracks. Due to the randomness and locality of crack propagation, it is difficult to predict the loca- tion of cracks by traditional monitoring methods. To solve this problem, the influence of spatial positions of monitoring points on inspection zones is represented by a weight index, and the weight index is determined by the distance measure method proposed in this paper. Through the weighted linear fusion method, the entropy of multiple monitoring points is obtained for analyzing the behavior of dam cracks in the selected zones. Meanwhile, the catastrophe theory is used as the variation criterion of an entropy sequence in order to predict the instability time of dam cracks. Case studies are put forward on a high arch darn, and the fusion entropy is calculated according to the monitoring data from strain gauges. Results show that the proposed method can effectively predict the occurrence time and location of dam cracks regardless of the layout of monitoring instruments, and it is a new way to analyze the occurrence and propagation of dam cracks. 展开更多
关键词 ENERGY measured data entropy changes multiple monitoring points fusion concrete dam
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Tomographic TR-PIV measurement of coherent structure spatial topology utilizing an improved quadrant splitting method 被引量:19
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作者 YANG ShaoQiong JIANG Nan 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第10期1863-1872,共10页
In this paper,we calculated the spatial local-averaged velocity strains along the streamwise direction at four spatial scales according to the concept of spatial local-averaged velocity structure function by using the... In this paper,we calculated the spatial local-averaged velocity strains along the streamwise direction at four spatial scales according to the concept of spatial local-averaged velocity structure function by using the three-dimensional three-component database of time series of velocity vector field in the turbulent boundary layer measured by tomographic time-resolved particle image velocimetry.An improved quadrant splitting method,based on the spatial local-averaged velocity strains together with a new conditional sampling phase average technique,was introduced as a criterion to detect the coherent structure topology.Furthermore,we used them to detect and extract the spatial topologies of fluctuating velocity and fluctuating vorticity whose center is a strong second-quadrant event(Q2) or a fourth-quadrant event(Q4).Results illustrate that a closer similarity of the multi-scale coherent structures is present in the wall-normal direction,compared to the one in the other two directions.The relationship among such topological coherent structures and Reynolds stress bursting events,as well as the fluctuating vorticity was discussed.When other burst events are surveyed(the first-quadrant event Q1 and the third-quadrant event Q3),a fascinating bursting period circularly occurs:Q4-S-Q2-Q3-Q2-Q1-Q4-S-Q2-Q3-Q2-Q1 in the center of such topological structures along the streamwise direction.In addition,the probability of the Q2 bursting event occurrence is slightly higher than that of the Q4 event occurrence.The spatial instable singularity that almost simultaneously appears together with typical Q2 or Q4 events has been observed,which is the main character of the mutual induction mechanism and vortex auto-generation mechanism explaining how the turbulence is produced and maintained. 展开更多
关键词 turbulent boundary layer coherent structure BURST TR-PIV Q2/Q4 local-averaged velocity strain quadrant splittingmethod
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