利用InSAR技术获取三峡地区的数字高程模型   总被引：13，自引：8，他引：5  

乔学军  李澍荪  王琪  游新兆  杜瑞林 《大地测量与地球动力学》2003,23(2):122-127

利用先进的合成孔径雷达干涉测量(InSAR)技术，使用38幅1992～2000年间三峡地区的ERS卫星SAR图像，并利用USGS的低精度DEM，得到了该地区的DEM，与GPS高程结果对比的差值为15～128m。干涉结果表明，基线小于200m的串行数据图像对具有较好的相干性；基线大于200m、在晚春和夏季观测的串行数据图像对容易出现失相关，而几乎所有重复轨道的SAR图像对在进行配准时都不相关。为了进一步获得三峡地区较高精度的数字高程模型，在该地区建立了角反射器，为研究和监测三峡地质灾害与地壳运动奠定了良好的基础。  相似文献   

昆仑山区综合科学考察的新进展     

郑度  潘裕生  武素功  张青松 《山地学报》1989,(2)

中国科学院青藏高原综合科学考察队,在总结1987年喀喇昆仑山-西昆仑山综合科学考察成果的基础上,于1988年6—9月,又考察了西昆仑山东部地区、中昆仑山区。通过考察,在高原的形成、演化,自然环境变迁,生物区系的种类组成、起源、演化,自然地域的分异规律及发展趋势等方面,取得了重要证据和新进展。  相似文献   

横断山区综合自然区划纲要     

杨勤业  郑度 《山地学报》1989,(1)

横断山区地域分异明显。各自然地理要素作地带性组合,自然地理环境呈水平分异,农业土地利用也大体呈纬向带状分布。根据温度和水分条件的地域组合及地势差异,将横断山区划分为5个自然地带、9个自然区,并与以往的方案进行了比较,阐述了自然地带界线的划分及各带特征。  相似文献   

济南海泡石的矿物学研究及成因     

杜心君 《山东国土资源》1986,(2)

一、前言海泡石(Sepiolite)是一种罕见而有用的层状镁质硅酸盐矿物,它是热液作用或风化作用的产物,这种矿物国内过去很少发现和报导。近年来在湖南、江西等地的二叠系地层中发现具工业价值的海相沉积海泡石粘土矿床。由于它具有耐热、耐盐浸及高粘度等特性,是优质钻探泥浆原料,在地热、石油和深海钻探中尤为宝贵,在工业上十分有用。据报导,海泡石发现于1750年,但直到1937年才确定它是一种独立矿物。1955年提出海泡石的结构模型。1957年Brauner和Preisinger在前人工作的基础上对海泡石的结构  相似文献   

Stability of thermonuclear reaction affected by gravitational force   总被引：5，自引：0，他引：5  

Du Jiulin  Chen Fusheng 《Astrophysics and Space Science》1992,195(2):349-357

A reaction-diffusion equation describing thermonuclear reaction system affected by gravitational force and temperature gradient is obtained by using the theory of nonequilibrium thermodynamics. We take CNO cycle as an example to investigate the effects of the gravitional force and temperature gradient on the stability of nuclear reaction inside the star. The stability criterion of the stellar structure has been analysed and some attractive results have also been discussed.  相似文献   

我国洞体应变固体潮调和分析结果   总被引：3，自引：1，他引：2  

杜慧君  丁伟民  周翠屏  陈晋 《大地测量与地球动力学》1993,(4)

本文扼要介绍了我国洞体应变观测现状,公布了18个台站的调和分析结果,同时公布了国外同类仪器优质台站的计算结果,以作比较。  相似文献   

环境工程地质质量多级模糊综合评判的基本思想与步骤     

张骏  杜东菊  彭建兵 《地球科学与环境学报》1991,(3)

环境工程地质质量综合评价是一个复杂的系统工程。影响质量评价的因素众多而又十分复杂,且各因素的影响程度也不相同,质量优劣的分级界线亦是模糊的。本文仅就采用多级模糊综合评判的方法,考虑多个因素的综合作用,对环境工程地质质量进行评价的基本思想途径与步骤方法,作一初步论述。此方法清晰、易用,能使更多影响质量评价的因素真实参与评判。这是一条环境工程地质质量评价由定性走向定量的有效途径,值得探索。  相似文献   

Microsampling Lu–Hf geochronology on mm‐sized garnet in eclogites constrains early garnet growth and timing of tectonometamorphism in the North Qilian orogenic belt          下载免费PDF全文

Hao Cheng  Ying Zhou  Kai‐Yang Du  Ling‐Min Zhang  Tian‐Yi Lu 《Journal of Metamorphic Geology》2018,36(8):987-1008

This study presents Lu–Hf geochronology of zoned garnet in high‐P eclogites from the North Qilian orogenic belt. Selected samples have ~mm‐sized garnet grains that have been sampled with a micro‐drill and analysed for dating. The Lu–Hf dates of bulk garnet separates, micro‐drilled garnet cores and the remnant, rim‐enriched garnet were determined by two‐point isochrons, with cores being consistently older than the bulk‐ and rim‐enriched garnet. The bulk garnet separates of each sample define identical garnet–whole rock isochron date of c. 457 Ma. Consistent U–Pb zircon dates of 455 ± 8 Ma were obtained from the eclogite. The Lu–Hf dates of the drilled cores and rim‐rich separates suggest a minimum garnet growth interval of 468.9 ± 2.4 and 452.1 ± 1.6 Ma. Major and Lu element profiles in the majority of garnet grains show well‐preserved Rayleigh‐style fractionated bell‐shaped Mn and Lu zoning profiles, and increasing Mg from core to rim. Pseudosection modelling indicates that garnet grew along a P–T path from ~470–525°C and ~2.4–2.6 GPa. The exceptional high‐Mn garnet core in one sample indicates an early growth during epidote–blueschist facies metamorphism at <460°C and <0.8 GPa. Therefore, the Lu–Hf dates of drilled cores record the early prograde garnet growth, whereas the Lu–Hf dates of rim‐rich fractions provide a maximum age for the end of garnet growth. The microsampling approach applied in this study can be broadly used in garnet‐bearing rocks, even those without extremely large garnet crystals, in an attempt to retrieve the early metamorphic timing recorded in older garnet cores. Given a proper selection of the drill bit size and a detailed crystal size distribution analysis, the cores of the mm‐sized garnet in most metamorphic rocks can be dated to yield critical constraints on the early timing of metamorphism. This study provides new crucial constraints on the timing of the initial subduction (before c. 469 Ma) and the ultimate closure (earlier than c. 452 Ma) of the fossil Qilian oceanic basin.  相似文献   

Multiperiodicity and physical nature of the δ Sct star GSC 2683-3076     

Ai-Ying Zhou  E. Rodríguez  Zong-Li Liu  Bai-Tian Du 《Monthly notices of the Royal Astronomical Society》2001,326(1):317-325

We present the results of a CCD Johnson V and photoelectric Strömgren uvbyβ photometric study of the recently discovered multiperiodic δ Sct star GSC 2683-3076. Our data set mainly consists of 2874 differential measurements in V together with a few data collected into the uvbyβ system. Additional unfiltered CCD measurements were also carried out. A set of seven best-fitting pulsation frequencies representing the light variations of the variable has been detected. The spectral type of the variable is found to be A9V or F0V. Using the uvbyβ indices the following main physical parameters for the variable have been derived: T _eff=7230 K , M _V =1.95 mag , log  g =3.90 , M =1.85 M_⊙ , R =2.30 R_⊙ , ρ =0.16  ρ _⊙ , age =1.0 Gyr , metal abundance [Me/H]=0.16 and distance modulus =8.4 mag . GSC 2683-3076 is found to be a Population I δ Sct star, slightly metal-enriched, evolving on its main-sequence stage. A mixture of radial and non-radial modes seems to be present in the pulsation of this variable. This star is also known as H133 in the young open cluster NGC 6871, however arguments are given that address this star as a non-member of the cluster. The uvbyβ photometry available in the literature for NGC 6871 is also discussed.  相似文献   

Change Laws of Intensity of Moderate-Small Earthquakes (2.0≤Ms≤5.5)     

Du XingxinSeismological Bureau of Shaanxi Province  Xi'an  China 《中国地震研究》1997,(4)

The change laws of intensity of nearly 200 moderate-small earthquakes with Ms=2.0~5.5 occurring on the Chinese mainland since 1954 have been analyzed and are compared with that of moderately strong earthquakes(Ms≥5.0).The results show that there is quite obvious regionality in the statistical laws by both moderate-small earthquakes and moderately strong earthquakes:attenuation of intensity in Eastern China is slower than that in Western China and the ratio of the major axis to the minor axis of iso-seismal lines in Eastern China is smaller than that in Western China.The results also show that for a fixed magnitude the attenuation of intensity of moderate-small earthquakes is faster when intensity is higher than V and slower when intensity is lower than V-in comparison with that of moderately strong earthquakes.Furthermore,there also have been some differences in the aspects as intensity-magnitude relation between statistical laws of moderate-small earthquakes and moderately strong earthquakes.These di  相似文献