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101.
延长油田区块位于鄂尔多斯盆地陕北斜坡东部延安单斜的中间部位,为研究天然气储层及储层中高含气分布区,2008年在延长油田区块内完成三维地震勘探344km2。本文对三维地震资料应用吸收系数、频谱分解、振幅衰减等地震属性进行流体识别试验。试验结果表明振幅衰减对含气层段异常响应相对敏感,吸收系数对高含气层段有一定反映。利用天然气储层各层段振幅衰减极大值,参考吸收系数剖面的高值层段,分析预测了三维区块含气概率高的平面分布区,2009年在预测的含气概率高分布区进行了探井验证,取得了比较理想的效果。  相似文献   
102.
Eight spatial structure types are determined through morphology, hydrogeology, hydrology and impulse response in karst districts, with the well studied Houzhai subterranean stream in Puding, Guizhou Province as a sample research area. These types contain peak-forest basin, peak-forest laterite platform, resurrected peak-forest basin, old peak-forest-funnel depression, peak-forest-funnel, peak-forest-funnel depression, peak-cluster valley and peak-forest-doline. In the area, each of them has its respective surface and subterranean structural feature, and morphology, hydrogeology, hydrology and impulse response as well. The difference of responses of subsurface system in different spatial structure types are obtained by time series analysis, frequency spectrum research and decline curve calculation of material current. According to the analysis of the aquifer feature, the upper reaches of suburfall stream is dominated by pipeline flow, the lower reaches is characterized by braided fissure flow drainage system and mixed characteristic exists in the middle reaches. The result of the impulse test shows that the large ascending range of stage in the test on swash condition is in fissure system. However, in pipeline type, especially in the subterranean stream where there is waterfall or incomplete fill of underground water, the ascending range of stage is one quantity level less than the impulse range of stage at some fissure types, showing that change range of stage can indicate the spatial structure characteristics of certain area upper the station. The main direction of karst geomorphic evolution there is positive course except in the west area. It can be seen that karst geomorphological evolution direction can change when discharge datum plane influences some part of a relatively large drainage. In certain time unit, the upper reaches are controlled by old datum plane and the lower reaches by new datum plane. Two opposite geomorphological evolution directions can exist in one drainage.  相似文献   
103.
Interdecadal and interannual variations of saline-alkali land area in Qian’an County, Jilin Province, China were comprehensively analyzed in this paper by means of satellite remote sensing interpretation, field flux observations and regional climate diagnosis. The results show that on the interannual scale, the impact of climate factors accounts for 71.6% of the total variation of the saline-alkali land area, and that of human activities accounts for 28.4%. Therefore the impact of climate factors is obviously greater than that of human activities. On the interdecadal scale, the impact of climate factors on the increase of the saline-alkali land area accounts for 43.2%, and that of human activities accounts for 56.8%. The impact of human activities on the variation of saline-alkali land area is very clear on the interdecadal scale, and the negative impact of human activities on the environment should not be negligible. Besides, changes in the area of heavy saline-alkali land have some indication for development of saline-alkali land in Qian’an County.  相似文献   
104.
VELOCITIES OF PRECURSOR SOLITON GENERATION IN SINGLE LAYER FLOW   总被引:3,自引:0,他引:3  
ImODUcrIONThegeneratingveodtyofprecmeorsolitonswasstudiedbyGrimshawetal.(l986),Wu(l987)andbeetal.(1989).TheydidnotgivetherelationbeweenthegeneratingvelocitiesandtopographyintenSityandthereexistSanunknownparameterh,inthetheoryofboetal.(l989),sotheprevioustheorycannotprediCtthegeneratingvelodtAs.ThisfurtherstudyonthetheoryofXuetal.(l996)ahetoconstIUCtatheoryonthegeneratingvefodtiesofsinglelayerflowfondbytopography.InSeCtion2,thernassandenergyoftheprecursorsolitongenerationaredetendnedint…  相似文献   
105.
1 INTRODUCTION Filaments are cool, dense material suspended in the hot, tenuous corona. It is widely accepted that the global magnetic field surrounding the filaments plays a key role in their formation, structure and stability (Tandberg-Hanssen1995). Fil…  相似文献   
106.
We present quasi-simultaneous VLBI images of the GHz-Peaked-Spectrum radio source OQ 208 obtained with the Very Long Baseline Array at 1.4,1.7,2.3,5.0,8.4,15.4GHz and the European VLBI Network at 6.7 GHz.The low frequency(1.4,1.7 and 2.3GHz)ob- servations reveal a weak and extended steep-spectrum component at about 30mas away at position angle-110°,which may be a remnant emission.The radio structure of OQ 208 con- sists of two mini-lobes at 5.0,6.7,8.4 and 15.4 GHz.Our spectral analysis further confirms that the southwest lobe undergoes free-free absorption and finds that the free-free absorption is stronger in the inner region.By fitting the 8.4 GHz images from 1994 to 2005,we obtain a separation speed of 0.031±0.006 mas yr~(-1)between the two mini-lobes.This indicates a jet proper motion of 0.105±0.020 c and a kinematic age of 219±42 yr for the radio source.  相似文献   
107.
蔡敏  黄艳  朱宵峰  沈锦栋  金培  吴惠娟 《气象》2009,35(7):95-100
地质灾害成因复杂,其中以气象因素、地质地貌因素引发的地质灾害最为常见.以金华地区为例,通过对金华市地质地貌条件及其对地质灾害点的调查,将全区划分为4个地质灾害隐患风险等级的网格区域.在此基础上利用金华中尺度气象资料,采用BP神经网络模型,建立地质灾害细网格预报模型,对该模型进行模拟和预报试验.结果表明,合理的隐患风险等级分区能使预报模型更符合科学规律,而采用分布较细的中尺度资料作为预报因子能进一步提高预报精度.模型的预报结果达到一定的可信度,为防灾减灾工作提供了科学依据.  相似文献   
108.
We present optical luminosity functions(LFs) of galaxies in the~(0.1) g,~(0.1) r,~(0.1) i bands, calculated using data in~40 deg~2 sky area of the LAMOST Complete Spectroscopic Survey of Pointing Area(LaCoSSPAr) in the Southern Galactic Cap. Redshifts for galaxies brighter than r = 18.1 were obtained mainly with LAMOST. In each band, LFs derived using both parametric and non-parametric maximum likelihood methods agree well with each other. In the0.1 r band, our fitting parameters of the Schechter function are φ_*=(1.65 ± 0.36) × 10~(-2) h~3 Mpc~(-3), M_*=-20.69 ± 0.06 mag and α =-1.12 ± 0.08,which agree with previous studies. Separate LFs are also derived for emission line galaxies and absorption line galaxies. The LFs of absorption line galaxies show a dip at~(0.1) r ~18.5 and can be fitted well by a double-Gaussian function, suggesting a bimodality in passive galaxies.  相似文献   
109.
On the Collision Nature of Two Coronal Mass Ejections: A Review   总被引:1,自引:0,他引:1  
Observational and numerical studies have shown that the kinematic characteristics of two or more coronal mass ejections (CMEs) may change significantly after a CME collision. The collision of CMEs can have a different nature, i.e. inelastic, elastic, and superelastic processes, depending on their initial kinematic characteristics. In this article, we first review the existing definitions of collision types including Newton’s classical definition, the energy definition, Poisson’s definition, and Stronge’s definition, of which the first two were used in the studies of CME–CME collisions. Then, we review the recent research progresses on the nature of CME–CME collisions with the focus on which CME kinematic properties affect the collision nature. It is shown that observational analysis and numerical simulations can both yield an inelastic, perfectly inelastic, merging-like collision, or a high possibility of a superelastic collision. Meanwhile, previous studies based on a 3D collision picture suggested that a low approaching speed of two CMEs is favorable for a superelastic nature. Since CMEs are an expanding magnetized plasma structure, the CME collision process is quite complex, and we discuss this complexity. Moreover, the models used in both observational and numerical studies contain many limitations. All of the previous studies on collisions have not shown the separation of two colliding CMEs after a collision. Therefore the collision between CMEs cannot be considered as an ideal process in the context of a classical Newtonian definition. In addition, many factors are not considered in either observational analysis or numerical studies, e.g. CME-driven shocks and magnetic reconnections. Owing to the complexity of the CME collision process, a more detailed and in-depth observational analysis and simulation work are needed to fully understand the CME collision process.  相似文献   
110.
空间VLBI的研究现状   总被引:2,自引:0,他引:2  
沈志强 《天文学进展》1998,16(2):117-134
评述了过去近三十年中空间VLBI的发展.其内容包括空间VLBI的简短发展历史,空间VLBI与地面VLBI的不同、空间VLBI的目前状况和空间VLBI的未来展望。着重介绍了作为首次空间VLBI的VSOP的各个方面情况,并给出了VSOP的连续谱、谱线普查样本,供参考。  相似文献   
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