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51.
纬向切变基流中的非线性正压Rossby波   总被引:2,自引:0,他引:2  
何建中 《气象学报》1994,52(4):433-441
在半地转近似下,用相角函数方法得到了包含纬向基流及其切变的非线性常微分方程。利用常微分方程解的拓扑性质的定性理论,直接得到该方程存在有限振幅的周期波解与孤立波解即非线性正压Rossby波解存在的条件,由此分析了纬向切变基流对波解存在的影响。最后利用函数逼近法求得了非线性正压Rossby波解的显式表达式。结果表明,纬向切变基流对波的影响不仅表现在波的存在方面,而且还表现在波的形态方面,反映了波的非线性特点和基流对波动的作用。  相似文献   
52.
斜压半地转模式中的非频散周期解   总被引:2,自引:0,他引:2  
给出了3个通量矢量,从而将非线性平流项表示为3个通量矢量的旋度和散度,它们分别对纬向风和经向风的低频加速产生贡献。经过卷积运算,还建立了低频变化的动力学模型。给出了通量矢量E.、G1.、G2.等的空间分布及其相应的流函数与势函数的水平分布和时间演变,从而指出,瞬变扰动间的相互作用对流动具有低频加速作用。  相似文献   
53.
湘东南地区震旦纪地层的新划分与区域对比   总被引:1,自引:0,他引:1  
黄建中  唐晓珊 《湖南地质》1994,13(3):129-136
本文采用多重地层划分和构造地层法,研究并重建了湘东南地区震旦系新层序,厘定了泗洲山组、天子地组、正园岭组、埃岐岭组、丁腰河组的含义及其划分、对比标志。认为该浊积碎屑岩系中的两套砾岩,是冰成作用的产物,可与湘中、湘西乃至华南地区的震旦系对比。同时指出孩区有板溪期的沉积,并建立了青白口系大江边组。  相似文献   
54.
Based on the improved hydrofracturing method, the in-situ principal stresses are determined in the north, northeast, south and the northwest of China, and the results of many fault-plane solutions, crustal deformations, geological and geophysical observations are used to discuss the distribution of subcrustal stress in space, the difference between seismically active regions and stable regions, and the variations of the stress field near the source region before and after the Tangshan earthquake. Finally, the characteristics of intraplate tectonic stress fields in China are explained in relation with the combined actions of the movement of the major Indian Ocean, Pacific and Philippine Sea plates.  相似文献   
55.
最近十余年来,我国古地磁学工作者曾对南方震旦纪地层以及北方蓟县的元古代地层做过一些古地磁学测定,并且对某些地质现象进行了解释。但是,对再早一些时期岩石的古地磁学研究仍属空白。地球的基本磁场主要起源于地球内部,它的参量必然反映地球的内部特征。按照地磁场的轴向地心偶极子假定,古地磁学的典型研究成果——视古地磁极移动轨迹应与地壳的构造发育演化过程有着内在的联系。太行山区是华北地台中、下元古界一个颇为发育的地区,本文简要报道作者对分布在该区地质年龄约为-2300百万年至-1650百万年的滹沱超群和长城系的古地磁学初步测定结果,并结合太行山区元古代早期和中期的大地构造问题提出粗浅的看法。  相似文献   
56.
Based on the fluorescence microscopic study, organic compositional analysis and simulating experiments on core samples and cuttings in the Suqiao area, it is found that the Carboniferous-Permian coal-bearing formations have substrata rich in spore, cuticle, resin and bark. These substrata have high potential for hydrocarbons, with S1 + S2 high up to about 200, high productivity of liquid hydrocarbons (73.5 mg / g or more) and natural gases (up to 194 ml / g). The substrata are thought to be an important source for natural gases and condensates found in this area. According to biomarker compounds and carbon and hydrogen isotope data from the Suqiao natural gas-condensate field, the coal and its simulating products, characteristics of coal-generated gases and oils from a special kind of coal and their correlation methods are discussed in the paper. In terms of the geochemical conditions of formation the distribution regularities of paralic coal rich in hydrogen, the commercial prospects of Carboniferous-Permian coal-generated oils have been evaluated as well.  相似文献   
57.
Natural underground coal fires are fires in coal seams occurring subsurface. The fires are ignited through a process named spontaneous combustion, which occurs based on a natural reaction but is usually triggered through human interaction. Coal mining activities expose coal to the air. This leads to the exothermal oxidation of the carbon in the coal with the air's oxygen to CO2 and – under certain circumstances – to spontaneous combustion. Coal fires occur in many countries world wide – however, currently the Chinese coal mining industry faces the biggest problems with coal fires. Coal fires destroy the valuable resource coal and furthermore lead to many environmental degradation phenomena such as the deterioration of surrounding vegetation, land subsidence and the emission of toxic gasses (CO, N2O). They additionally contribute to the emission of green house relevant gasses such as CO2 and CH4 to the atmosphere.In this paper we present thermal characteristics of coal fires as measured in-situ during a field campaign to the Wuda coal fire area in south-central Inner Mongolia, China. Thermal characteristics include temperature anomaly measurements at the surface, spatial surface temperature profiles of fire areas and unaffected background areas, diurnal temperature profiles, and temperature measurements inside of coal fire induced cracks in the overlying bedrock. For all the measurements the effects of uneven solar heating through influences of slope and aspect are considered.Our findings show that coal fires result in strong or subtle thermal surface anomalies. Especially the latter can easily be influenced by heating of the surrounding background material through solar influences. Temperature variation of background rocks with different albedo, slope, aspect or vegetation cover can substantially influence the detectability of thermal anomalies. In the worst case coal fire related thermal anomalies can be completely masked by solar patterns during the daytime. Thus, night-time analysis is the most suitable for thermal anomaly mapping of underground coal fires, although this is not always feasible. The heat of underground coal fires only progresses very slowly through conduction in the rock material. Anomalies of coal fires completely covered by solid unfractured bedrock are very weak and were only measured during the night. The thermal pattern of underground coal fires manifested on the surface during the daytime is thus the pattern of cracks and vents, which occur due to the volume loss underground and which support radiation and convective energy transport of hot gasses. Inside coal fire temperatures can hardly be measured and can only be recorded if the glowing coal is exposed through a wider crack in the overlaying bedrock. Direct coal fire temperatures measured ranged between 233 °C and 854 °C. The results presented can substantially support the planning of thermal mapping campaigns, analyses of coal fire thermal anomalies in remotely sensed data, and can provide initial and boundary conditions for coal fire related numerical modeling.In a second paper named “Thermal Characteristics of Coal Fires 2: results of measurements on simulated coal fires” [Zhang J., Kuenzer C., Tetzlaff A., Oettl D., Zhukov B., Wagner W., 2007. Thermal Characteristics of Coal Fires 2: Result of measurements on simulated coal fires. Accepted for publication at Journal of Applied Geophysics. doi:10.1016/j.jappgeo.2007.08.003] we report about thermal characteristics of simulated coal fires simulated under simplified conditions. The simulated set up allowed us to measure even more parameters under undisturbed conditions — especially inside fire temperatures. Furthermore we could demonstrate the differences between open surface coal fires and covered underground coal fires. Thermal signals of coal fires in near range thermal remotely sensed imagery from an observing tower and from an airplane are presented and discussed.  相似文献   
58.
朱同兴  潘桂棠等 《地质通报》2002,21(11):717-722
藏南喜马拉雅北坡二叠系基性火山岩位于聂拉木县色龙东山。岩石地球化学特征表明,无论是基龙组火山岩还是色龙群火山岩,都具有大陆拉伸-大陆裂谷环境火山岩系的主、微量元素地球化学特征。据此,判断两套基性火山岩的性质和喷发构造环境相同。该区二叠纪大陆拉伸-裂谷火山活动标志着冈瓦纳超级古大陆开始裂离、解体。  相似文献   
59.
GPS定位技术在高层建筑施工基准传递中的应用   总被引:4,自引:0,他引:4  
在高层建筑施工中,基准传递是一项极为重要的测量工作,为了满足现代建筑工程快速、高效、优质的施工需要,文中提出应用GPS定位技术实施施工基准定位的方法,并结合工程实测就作业过程作了阐述。结果表明,在超高层建筑的基准传递中,应用GPS是一种行之有效的新方法。  相似文献   
60.
赤峰西部地区金矿床成矿时代及其成矿机制的新认识   总被引:18,自引:0,他引:18  
赤峰西部地区产华北板块与兴蒙造山带拼合部位南侧的板块北部边缘带上,为著名的赤峰-朝阳金矿集中区重要金矿产地之一。本区金矿床包括两种类型:柴胡栏子金矿床为蚀变岩型金矿床为蚀变岩型金矿;莲花山和红花沟金矿床属石英脉型。诸多地质事实表明这些矿床的形成均与中基性岩浆活动密切相关。野外观察和同位素年代学资料说明中基性岩浆活动发生在印支期。因此,笔者提出本区金矿成矿时代为印支期的新认识,否定了以往一些研究者提出本区金成矿作用是发生在燕山期或海西期的看法。同时,在综合分析基础上,提出本区金矿床是在印支期构造-岩浆活动作用下、区域隆起的过程中形成的产物,从而对本区金矿床的形成机制做出了新的解释。  相似文献   
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