长春双阳地震台数字水管仪倾斜潮汐观测质量评定   总被引：2，自引：2，他引：0  

于天龙  陈耿琦  李海燕  符岩峰  张可佳  张宗峰 《大地测量与地球动力学》2007,27(Z1):89-92

对双阳地震台DSQ型水管倾斜仪2001～2006年倾斜潮汐观测资料作了质量评定,检定结果显示:观测资料连续,仪器观测状况稳定,年零漂、年变幅小,噪声水平低.  相似文献   

Coupled solution of heat and moisture flow in unsaturated clay barriers in a repository geometry Int. J. Numer. Anal. Meth. Geomech. (DOI: 10.1002/nag.565)     

G. J. Chen  A. Ledesma 《国际地质力学数值与分析法杂志》2007,31(8):1067-1069

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Numerical modeling of secondary migration and its applications to Chang-6 Member of Yanchang Formation (Upper Triassic), Longdong area,Ordos Basin,China     

Luo  XiaoRong  Yu  Jian  Zhang  LiuPing  Yang  Yang  Chen  RuiYin  Chen  ZhanKun  Zhou  Bo 《中国科学:地球科学(英文版)》2007,50(2):91-102

Mathematic modeling, established on the basis of physical experiments, is becoming an increasingly important tool in oil and gas migration studies. This technique is based on the observation that hydrocarbon migration tends to take relative narrow pathways. A mathematical model of hydrocarbon migration and accumulation is constructed using the percolation theory. It is then calibrated using physical experimental results, and is tested under a variety of conditions, to understand the applicability of the model in different migration cases. Through modeling, dynamic conditions of large-scale migration pathways within homogeneous formations can be evaluated. Basin-scale hydrocarbon migration pathways and their characteristics are analyzed during the model application to the Chang-8 Member of the Triassic Yanchang Formation in Longdong area of Ordos Basin. In heterogeneous formations, spatial changes in fluid potential determine the direction of secondary migration, and heterogeneity controls the characteristics and geometry of secondary migration pathways.

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基于多尺度纹理和光谱信息的SVM分类研究   总被引：3，自引：0，他引：3  

陈晨  张友静 《测绘科学》2009,34(1)

基于单尺度纹理和光谱信息的地物分类较难取得理想效果,本文结合多尺度纹理与光谱信息,运用SVM分类方法,对IKONOS遥感影像进行分类。结果表明:结合多尺度纹理和光谱信息的SVM高分辨率遥感影像分类,能够更好地描述地物,分类总体精度达到83.9%,与基于光谱信息的最大似然法和基于单尺度纹理和光谱信息的SVM分类方法比较,分类精度分别提高了13.8%和4.9%,该方法有助于提高高分辨率影像的分类正确率。  相似文献   

基础地理信息动态更新技术体系初探   总被引：15，自引：2，他引：13  

陈军  赵仁亮  王东华 《地理信息世界》2007,5(5):4-9

近年来,我国测绘部门完成了国家级基础地理信息数据库的"初始建库",基础测绘工作重点已转向持续更新和灵性服务。未来的基础地理信息"应需适时更新"将体现更新内容灵性化、更新周期适时化、更新方式多元化等特点,其主要业务模式包括变化监测、变化测定、主数据库更新和产品更新及服务四大部分。为了有效开展"应需适时更新",应构建包括动态监测与数据预处理、变化信息采集与处理、数据库与产品更新、更新信息网络化服务四大主体部分的动态更新技术体系。该体系是信息化测绘技术体系的一个重要组成部分,应加强对其关键技术的研发,开展技术装备成套化和业务体系建设。  相似文献   

Mid-to-Far Infrared Spectral Energy Distribution of Galaxies in the Spitzer First Look Survey Field     

Xiao-Qing Wen    Hong Wu  Chen Cao  Xiao-Yang Xia  Department of Physics  Tianjin Normal University  Tianjin National Astronomical Observatories  Chinese Academy of Sciences  Beijing   《中国天文和天体物理学报》2007,7(2):187-198

We made model fitting to the mid-to-far infrared spectral energy distributions (SEDs) for different categories of galaxies in the main extragalactic field of the Spitzer First Look Survey with the aid of spectroscopic information from the Sloan Digital Sky Survey. We find that the mid-to-far infrared SEDs of HII galaxies, mixture type galaxies and LINERs can be well fitted by the one-parameter (α) dust model of Dale et al. plus the 13 Gyr dust-free elliptical galaxy model. The statistics of α values indicates that all these galaxies tend to be quiescent, although the HII galaxies are relatively more active than the LINERs. The mid- infrared SEDs of absorption galaxies are well fitted simply by the 13 Gyr dust-free elliptical galaxy template, and the near-to-mid infrared SEDs of QSOs can be represented by AGN NGC 5506.  相似文献   

Current and Thermohaline Characteristics of the Arabian Sea During January 1998     

CHEN Meixiang)  ZUO Juncheng)  LI Peiliang)  DU Ling)  and LI Lei)) Oceanography Department  Ocean University of China  Qingdao  P. R. China ) Key Laboratory of Coastal Disaster  Defence  Ministry of Education  Hohai University  Nanjing  P. R. China 《中国海洋大学学报(英文版)》2007,6(2):117-124

Based on a ship survey during January 1998, the characteristics of the flow, the thermohaline properties and the volume transport of the Arabian Sea are discussed. A strong westward flow exists between 10.5?N and 11?N, part of which turns to the south as the Somali current near the coast at about 10?N and the rest turns north. At the passage between the African continent and the So- cotra Island, the northern branch separates into two flows: the left one enters the passage and the right one flows eastward along the southern slope of the island. Off the island the flow separates once more, most of it meandering northeast and a small fraction flow- ing southeast. Volume transport calculation suggests that the tidal transport is one or two orders of magnitude smaller than the total transport in this region and it becomes more important near the coast. The average velocity of the flow in the upper layer (0-150 m) is about 20 cm s-1, with a maximum of 53 cm s-1 appearing east of the Socotra Island, and the subsurface layer (200-800 m) has an aver- age velocity of 8.6 cm s-1; the velocity becomes smaller at greater depths. The depth of the seasonal thermocline is about 100 m, above which there is a layer with well mixed temperature and dissolved oxygen. High-salinity and oxygen-rich water appears near the surface of the northern Arabian Sea; a salinity maximum and oxygen minimum at 100 m depth along 8?N testifies the subduction of surface water from the northern Arabian Sea. Waters from the Red Sea and the Persian Gulf also influence the salinity of the area.  相似文献   

浙江省县域旅游经济增长的空间溢出效应   总被引：2，自引：1，他引：2  

陈晓艳  徐冬  黄睿  胡小海  黄震方  张郴 《地理科学进展》2020,39(9):1512-1521

论文以浙江省65个县域单元为例,综合运用探索性空间数据分析和空间杜宾模型,实证了2004—2016年浙江省县域旅游经济增长及其影响因素的空间溢出效应。结果表明:① 研究期内浙江省县域旅游经济整体表现出较强的空间依赖性,局部空间关联类型以高—高和低—低集聚为主,高—高集聚区主要位于中心市区,低—低集聚区主要位于浙西和浙南等地。旅游经济增长的空间自相关性表明考察其演化路径时不可忽视空间效应的存在。② 浙江省县域入境和国内旅游经济增长均存在显著的空间溢出效应,本地入境和国内旅游经济每增长1%,将会带动邻近县域入境和国内旅游经济分别增长0.192%和0.249%。经济发展水平、旅游资源禀赋、旅游基础设施和区位交通条件等均具有显著的空间溢出效应,忽视旅游经济增长的空间效应,将会高估这些因素的作用强度。③ 驱动旅游经济增长的各影响因素的作用强度和影响路径存在显著差异,未来应充分关注入境和国内旅游经济增长的空间依赖特征,将驱动旅游经济增长的各因素齐抓并举,方可实现县域旅游经济的高质量发展。  相似文献   

EUV and Magnetic Activities Associated with Type-I Solar Radio Bursts   总被引：1，自引：0，他引：1  

C. Y. Li  Y. Chen  B. Wang  G. P. Ruan  S. W. Feng  G. H. Du  X. L. Kong 《Solar physics》2017,292(6):82

Type-I bursts (i.e. noise storms) are the earliest-known type of solar radio emission at the meter wavelength. They are believed to be excited by non-thermal energetic electrons accelerated in the corona. The underlying dynamic process and exact emission mechanism still remain unresolved. Here, with a combined analysis of extreme ultraviolet (EUV), radio and photospheric magnetic field data of unprecedented quality recorded during a type-I storm on 30 July 2011, we identify a good correlation between the radio bursts and the co-spatial EUV and magnetic activities. The EUV activities manifest themselves as three major brightening stripes above a region adjacent to a compact sunspot, while the magnetic field there presents multiple moving magnetic features (MMFs) with persistent coalescence or cancelation and a morphologically similar three-part distribution. We find that the type-I intensities are correlated with those of the EUV emissions at various wavelengths with a correlation coefficient of 0.7?–?0.8. In addition, in the region between the brightening EUV stripes and the radio sources there appear consistent dynamic motions with a series of bi-directional flows, suggesting ongoing small-scale reconnection there. Mainly based on the induced connection between the magnetic motion at the photosphere and the EUV and radio activities in the corona, we suggest that the observed type-I noise storms and the EUV brightening activities are the consequence of small-scale magnetic reconnection driven by MMFs. This is in support of the original proposal made by Bentley et al. (Solar Phys. 193, 227, 2000).  相似文献   

Delineation of spatial redox zones using discriminant analysis and geochemical modelling in arsenic‐affected alluvial aquifers     

Jin‐Jing Lee  Cheng‐Shin Jang  Sheng‐Wei Wang  Chin‐Ping Liang  Chen‐Wuing Liu 《水文研究》2008,22(16):3029-3041

This study characterized the redox conditions in arsenic‐affected groundwater aquifers of the Lanyang plain, Taiwan. Discriminant analysis was adopted to delineate three redox zones (oxidative, transitional and reductive zones) in different aquifers and yielded 92·3% correctness on groundwater quality data. Arsenic is mainly distributed in the reductive zone, and arsenic distribution in the shallow aquifer is mainly affected by surface activities. According to PHREEQC modelling results, possible mechanisms for arsenic release to groundwater in Lanyang plain are explored. Arsenic released to groundwater in the oxidative zone (zone 1) is primarily caused by the oxidations of arsenic‐bearing pyrite minerals, and arsenate is the predominant species. While the reductive dissolution of Fe‐oxides are responsible for the high arsenic concentration found in the transitional and reductive zones (zones 2 and 3), arsenite is the predominant species. The reduction potential of groundwater rises as the depths and zones increase. Some sulphates may be reduced to form sulphide ions, which then react with arsenic to form arseno‐sulphide deposits (such as realgar, orpiment) and then slightly lower groundwater arsenic concentrations. A conceptual diagram which summarized the possible release processes of arsenic in different redox zones along groundwater flow in Lanyang plain is postulated. Arsenic‐bearing pyrite and arsenopyrite (FeAsS) are oxidized as they are exposed to the infiltrated oxygenated rainwater, releasing soluble arsenate Fe(II) and SO₄^2? into zone 1. The dissolution of arsenic‐rich Fe‐oxides due to the onset of reducing conditions in zones 2 and 3 is responsible for the mobility of arsenic and likely to be the primary mechanism of arsenic release to groundwater in the Lanyang plain Copyright © 2007 John Wiley & Sons, Ltd.  相似文献