用SSM/I微波遥感图像分析海上台风的螺旋云带   总被引：3，自引：2，他引：3  

游然  许健民  张文建 《气象学报》2002,60(4):477-485

文中介绍了美国国防气象卫星专用微波成像仪 (SSM /I)上各通道的特性 ,分析了大气中各种粒子 (尤其是云滴和降水滴 )对各通道辐射的吸收和散射效应。通过对SSM /I图像上台风单通道剖面、双通道散点图的分析 ,揭示了台风在微波图像上表现形式的内在物理原因。在此基础上 ,设计了一个降水指数 ,方法是 :将 85 .5GHz的吸收段对称拉伸到散射段的延长线上 ,然后求归一化后的 19.35 ,37.0GHz和经拉伸处理的 85 .5GHz图像 3者的平均值。 3个通道合成降水指数克服了 37.0GHz对大雨滴不敏感 ,和 85 .5GHz对中等大小雨滴不敏感的缺点 ,比原始单通道微波图像更清楚地显示了台风的螺旋云带结构  相似文献   

螺旋CT三维重建在骨盆骨折中的应用   总被引：2，自引：0，他引：2  

彭磊  徐春林  魏莉莉 《CT理论与应用研究》2002,11(3):39-41

目的：探讨用螺旋CT三维重建评价骨盆骨折的临床应用价值。方法：收集骨盆骨折17例，采用螺旋CT三维重建检查。结果：17例检查均取得清晰立体图像，且可消除某一骨性结构，单独观察骨盆某一组成骨的骨折情况。结论：螺旋CT三维重建在骨盆骨折的诊断、手术方案的设计及教学等有较高价值。  相似文献   

高压旋喷法在镇江市南徐路软基处理中的应用     

郑会俊 《江苏地质》2003,27(3):179-181

介绍了高压旋喷法在镇江市南徐路软土路基处理中的应用，提出了旋喷桩的施工工艺、质量控制要点，对应用效果作了简要评述。  相似文献   

青藏高原北部可可西里狮头山含硬玉岩类的基本特征及地质意义   总被引：4，自引：6，他引：4  

李才杨德明  和钟铧陈曼云 《地质通报》2003,22(5):297-302

描述了可可西里山南狮头山含硬玉岩类的岩石学、矿物学特征。含硬玉岩类的原岩为辉长岩，围岩为石炭—二叠系。由于变质作用不彻底，保留有原岩的矿物组合。典型的高压变质矿物组合为：钠长石 硬玉 霓石 蓝闪石 绿帘石 绿泥石。硬玉SiO2、FeO偏低，Al2O3、Na2O明显偏高，变质矿物组合中以富钠矿物为主，缺少石英，与国内外含硬玉岩类的原岩成分、变质矿物组合均不相同，是一种新的高压低温硬玉岩类。狮头山高压变质带向西延至若拉岗日、大横山一带，与北侧的西金乌兰—金沙江板块缝合带(西段)平行产出，以此推测缝合带南侧的羌北—昌都板块向北消减于巴颜喀拉板块之下。  相似文献   

高压旋喷桩桩周土摩阻力的分析与探讨   总被引：3，自引：0，他引：3  

胡焕校  刘静 《地质与勘探》2003,39(2):88-90

通过对旋喷桩的单桩静载试验，探讨了桩周土摩阻力作用的情况，通过计算和分析，得出了两个结论，为旋喷桩基础的设计提供参考。  相似文献   

福建龙永煤田二叠纪(竹蜓)生物带的面貌特征与对比     

胡兆曦 《中国煤田地质》2003,(4)

研究地层是有效寻找沉积矿产的重要基础,将龙永煤田内关于的层位及分带性与大区域上的相似层位作了对比,并论述了本煤田的特征与变迁的基本过程。最后,结合多年来的研究成果,就煤田内的产出情况,作了两点必要的说明。  相似文献   

High-pressure granulites: formation, recovery of peak conditions and implications for tectonics   总被引：51，自引：2，他引：51  

P. J. O'Brien  J. Rötzler 《Journal of Metamorphic Geology》2003,21(1):3-20

High‐pressure granulites are characterised by the key associations garnet‐clinopyroxene‐plagioclase‐quartz (in basic rocks) and kyanite‐K‐feldspar (metapelites and felsic rocks) and are typically orthopyroxene‐free in both basic and felsic bulk compositions. In regional metamorphic areas, two essential varieties exist: a high‐ to ultrahigh‐temperature group and a group representing overprinted eclogites. The high‐ to ultrahigh‐temperature type formerly contained high‐temperature ternary feldspar (now mesoperthite) coexisting with kyanite, is associated with garnet peridotites, and formed at conditions above 900 °C and 1.5 GPa. Clinopyroxene in subordinate basic rocks is Al‐rich and textural evidence points to a high‐pressure–high‐temperature melting history. The second variety contains symplectite‐like or poikilitic clinopyroxene‐plagioclase intergrowths indicating former plagioclase‐free, i.e. eclogite facies assemblages. This type of rock formed at conditions straddling the high‐pressure amphibolite/high‐pressure granulite field at around 700–850 °C, 1.0–1.4 GPa. Importantly, in the majority of high‐pressure granulites, orthopyroxene is secondary and is a product of reactions at pressures lower than the peak recorded pressure. In contrast to low‐ and medium‐pressure granulites, which form at conditions attainable in the mid to lower levels of normal continental crust, high‐pressure granulites (of nonxenolith origin) mostly represent rocks formed as a result of short‐lived tectonic events that led to crustal thickening or subduction of the crust into the mantle. Short times at high‐temperature conditions are reflected in the preservation of prograde zoning in garnet and pyroxene. High‐pressure granulites of both regional types, although rare, are known from both old and young metamorphic terranes (e.g. c. 45 Ma, Namche Barwa, E Himalaya; 400–340 Ma, European Variscides; 1.8 Ga Hengshan, China; 1.9 Ga, Snowbird, Saskatchewan and 2.5 Ga Jianping, China). This spread of ages supports proposals suggesting that thermal and tectonic processes in the lithosphere have not changed significantly since at least the end of the Archean.  相似文献   

Formation Environment of the High-Pressure Metamorphic Rocks, Western Tianshan, Xinjiang, China   总被引：1，自引：0，他引：1  

GAO Jun  WANG Zongxiu 《Continental Dynamics》1997,(1)

1.IntroductionFromexperimefltalphaseequilibrium,stableisotOPe,andthermo-barometricstudies,ProgradebineschistdineralparageneseshavebeenproducedexclusivelyatrelativelyhighPadratios(DeRoever,1956;Miyashiro,1961;DobretsovandSobolev,1984;Emst,1973,1988;Maruyamaetal.,1996).InthelastthreedeCades,withtheadvanceofplatetectonics,manygeologistssuggestedthatblueschists,representinghigh-Pressurelow-tCmperamre~rphism,areformedbysubductionofoceanicplate(Emst,1973).Blueschistshavealsobeenregardedasoneof…  相似文献   

单管高压旋喷注浆技术在砂层加固、止水工程中的应用   总被引：1，自引：0，他引：1  

李文华  张瑞琼 《江苏地质》2004,28(2):103-106

就其他工艺在砂层的加固、止水工程中难以解决的问题，提出了单管高压旋喷注浆技术，并通过一些工程实例证实此工艺的可行性。  相似文献   

Late-Stage Ductile Deformation in Xiongdian-Suhe HP Metamorphic Unit, North-Western Dabie Shan, Central China     

SuoShutian ZhongZengqiu ZhouHanwen YouZhendong 《中国地质大学学报(英文版)》2004,15(3):262-274

New structural and petrological data unveil a very complicated ductile deformation history of the Xiongdian-Suhe HP metamorphic unit, north-western Dabie Shun, central China. The finegrained symplectic amphibolite-facies assemblage and coronal structure enveloping eclogite-facies garnet,omphacite and phengite etc., representing strain-free decompression and retrogressive metamorphism,are considered as the main criteria to distinguish between the early-stage deformation under HP metamorphic conditions related to the continental deep subduction and collision, and the late-stage deformation under amphibolite to greenschist-facies conditions occurred in the post-eclogite exhumation processes.Two late-stages of widely developed, sequential ductile deformations D3 and D4, are recognized on the basis of penetrative fabrics and mineral aggregates in the Xiongdian-Suhe HP metamorphic unit, which shows clear, regionally, consistent overprinting relationships. D3 fabrics are best preserved in the Suhe tract of low post-D3 deformation intensity and characterized by steeply dipping layered mylonitic amphibolites associated with doubly vergent folds. They are attributed to a phase of tectonism linked to the initial exhumation of the HP rocks and involved crustal shortening with the development of upright structures and the widespread emplacement of garnet-bearing granites and felsic dikes. D4 structures are attributed to the main episode of ductile extension (D^24) with a gently dipping foliation to the north and common intrafolial, recumbent folds in the Xiongdian tract, followed by normal sense top-to-the northductile shearing (D^24) along an important tectonic boundary, the so-called Majiawa-Hexiwan fault (MHF), the westward continuation of the Balifan-Mozitan-Xiaotian fault (BMXF) of the northern Dabie Shan. It is indicated that the two stages of ductile deformation observed in the Xiongdian-Suhe HP metamorphic unit, reflecting the post-eclogite compressional or extrusion wedge formation, the subhorizontal ductile extension and crustal thinning as well as the top-to-the north shearing along the high-angle ductile shear zones responsible for exhumation of the HP unit as a coherent slab, are consistent with those recognized in the Dabie-Sulu UHP and HP metamorphic belts, suggesting that they were closely associated in time and space. The Xiongdian-Suhe HP metamorphic unit thus forms part of the Triassic(250-230 Ma) collision orogenic belt, and can not connect with the South Altun-North Qaidam-North Qinline UHP metamorphic belt formed durin~ the Early Paleozoic (500-400Ma).  相似文献