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291.
阐述了USB2.0高速总线的工作原理,并运用Cypress公司推出的USB2.0控制器CY7C68013芯片加上高速A/D转换芯片实现了高速A/D采样,为今后的USB高速应用打下了基础.  相似文献   
292.
The October 2005 series of earthquakes that occurred in the Gulf of Siğaçik (western Turkey) reveal the operation of pure strike-slip faults, as evidenced from the 49 focal mechanisms we determined, in a region dominated by N–S extension and bounded by well-documented graben structures. The sequence is characterized by the occurrence of three moderate size events (17 October 2005, 05:45 UTC, Mw 5.4; 17 October 2005, 09:46 UTC, Mw 5.8; and 20 October 2005, 21:40 UTC, Mw 5.8) with an eastward propagation and close spatial separation (< 6 km). We relocated over 200 aftershocks, combining phases from the Greek and Turkish seismological networks, which align roughly in a NE–SW cloud, but considerably spread after the first day of the sequence, indicating the simultaneous activation of multiple structures nearly orthogonal to the main rupture. It is hard to relate the occurrence of the events to any of the previously mapped faults in the region. The region of occurrence is a well-known geothermal area which implies that it is in a very unstable state, with the fault systems close to rupture and very sensitive to stress perturbations. Here we showed that the sequence is adequately explained by static stress triggering. It is worth noting that this sequence, though moderate in magnitudes, provides stronger evidence for the operation of sub-parallel strike-slip faults in the central Aegean Sea–western Turkey, north of the volcanic arc, which seem to be optimally oriented in the regional stress field and facilitate the Anatolia motion into the Aegean Sea.  相似文献   
293.
Satellite remote sensing data are usually used to analyze the spatial distribution pattern of geological structures and generally serve as a significant means for the identification of alteration zones. Based on the Landsat Enhanced Thematic Mapper (ETM+) data, which have better spectral resolution (8 bands) and spatial resolution (15 m in PAN band), the synthesis processing techniques were presented to fulfill alteration information extraction: data preparation, vegetation indices and band ratios, and expert classifier-based classification. These techniques have been implemented in the MapGIS-RSP software (version 1.0), developed by the Wuhan Zondy Cyber Technology Co., Ltd, China. In the study area application of extracting alteration information in the Zhaoyuan (招远) gold mines, Shandong (山东) Province, China, several hydorthermally altered zones (included two new sites) were found after satellite imagery interpretation coupled with field surveys. It is concluded that these synthesis processing techniques are useful approaches and are applicable to a wide range of gold-mineralized alteration information extraction.  相似文献   
294.
A synthesis of high-resolution (Chirp, 2–7 kHz) seismic profiles in the South Korea Plateau reveals that large masses of wavy stratified sediment (≈60–90 m thick) cover broad, gently sloping (<0·5°) ridges in water depths of 1000–2000 m. The wavy stratified sediment (WSS) is characterized by wavy (0·2–5 km in wavelength and <15 m in relief), continuous reflective layers with a basal deformed zone that overlies undeformed, strong reflectors. The WSS exhibits systematic variation in wave dimensions and thickness of internal reflective layers with changes in slope gradient. The troughs of the waves are commonly associated with internal growth faults, and wave amplitude generally increases with subbottom depth. On steep slopes around the ridges, the WSS masses are bounded downslope by slide and slump deposits including slightly translated or rotated WSS blocks. The acoustic and geometric characters, and association with downslope slides and slumps on the steeper slopes, suggest that the WSS masses were most probably formed by slow creep movement before slope failure. In the absence of significant sediment input to the South Korea Plateau, the deep (1000–2000 m in water depth) mass movements were probably triggered by earthquakes that have occurred frequently in this region. Some slightly displaced, intact WSS blocks in the associated slides and slumps downslope reflect a progressive evolution from submarine creep into slide and slump.  相似文献   
295.
 The 7 month-period (sub-Chandler) wobble is considered with respect to the nonlinear dynamical equation of polar motion. Starting with the frequency modulation of Chandler wobble (CW) in the model developed by introduction of damping from perturbed visco-elastic deformation, the rotation equation of the CW becomes a resonance model with a time-dependent parameter. According to evolution calculation, the parameter resonance model is essentially identical to the reality of CW observations. If the frequency of CW is modulated about 3 by visco-elastic deformation, then the amplitude of CW will be modulated by greater than 70. On the other hand, bifurcation may occur according to the nonlinear dynamical system of the parameter resonance model, i.e. a pair of solutions splitting from the main CW. One is the 7-month-period wobble and the other is a motion with a period of about 28 months. Although the latter is very weak, the 7-month-period wobble will be observed as the stability condition is satisfied. The maximum amplitude is about 22.89 mas and the average 12.65 mas. This is identical to what is observed in reality. Received: 7 April 2000 / Accepted: 5 March 2001  相似文献   
296.
The extension of eastern Avalonia from Britain through the NE German Basin into Poland is, in some sense, a virtual structure. It is covered almost everywhere by late Paleozoic and younger sediments. Evidence for this terrane is only gathered from geophysical data and age information derived from magmatic rocks. During the last two decades, much geophysical and geological information has been gathered since the European Geotraverse (EGT), which was followed by the BABEL, LT-7, MONA LISA, DEKORP-Basin'96, and POLONAISE'97 deep seismic experiments. Based on seismic lines, a remarkable feature has been observed between the North Sea and Poland: north of the Elbe Line (EL), the lower crust is characterised by high velocities (6.8–7.0 km/s), a feature which seems to be characteristic for at least a major part of eastern Avalonia (far eastern Avalonia). In addition, the seismic lines indicate that a wedge of the East European Craton (EEC) (or Baltica) continues to the south below the southern Permian Basin (SPB)—a structure which resembles a passive continental margin. The observed pattern may either indicate an extension of the Baltic crust much farther south than earlier expected or oceanic crust of the Tornquist Sea trapped during the Caledonian collision. In either case, the data require a reinterpretation of the docking mechanism of eastern Avalonia, and the Elbe–Odra Line (EOL), as well as the Elbe Fault system, together with the Intra-Sudedic Faults, appear to be related to major changes in the deeper crustal structures separating the East European crust from the Paleozoic agglomeration of Middle European terranes.  相似文献   
297.
用地震标定律研究丽江7.0级地震的破裂过程   总被引:7,自引:5,他引:7  
本根据Heaskell二维矩形地震破裂模式,导出了以ω立方的波谱衰减,在分析地震破裂过程特征、考虑三个主要的相似性假定基础上,即假定地震满足断层面几何相似、应力环境相似和动力学相似条件,研究了大小地震相似性问题的标度分析,建立了地震破裂和源参数之间的标定律关系。用云南地区20多年中数百个地震的地震矩M0、面波震级Ms和近震震级ML系统以及有关的地震参数,建立了适用于云南地区的地震标定律关系。由此  相似文献   
298.
丽江7.0级地震的地震地质构造背景分析   总被引:7,自引:3,他引:7  
周光全  张建国 《地震研究》1997,20(1):92-100
本文主要根据作者的野外地震地质调查,从震区地质构造条件与构造应力场特征出发,根据库仑-莫尔剪破裂准则计算,结合这次地震地表破坏特征和等烈度线形态特征综合分析认为,在北北西至近南北向主压应力作用下,丽江7.0级地震是玉龙雪山山前断裂活动的结果,地震时断层活动以倾为主,伴有一定的左旋扭动。并讨论了山前断裂的闭锁条件。  相似文献   
299.
青海共和7.0级地震与龙羊峡水库关系探讨   总被引:2,自引:2,他引:2  
龙羊峡水库建立于青海省和共盆地内,大坝围堰拦洪期间,于1981年11月23日在坝址附近发生最大震级Ms2.3的小震活动当时坝前壅水高度国39m。1986年11月大坝截流蓄水后约3年半,于1990年4月26日在距库尾约40km处发生Ms7.0级地震,其后至1994年10月发生Ms≥5级地震多次,且有震中逐渐靠近水库的趋势,共和7.0级地震引起了地震界是水库地震研究者的广泛关主,我们根据已发表的有关资  相似文献   
300.
1992年8月19日吉尔吉斯斯坦共和国苏撒孟尔盆地发生7.3级地震,主余震为6.7级。地震发生于北天山褶皱带内。震中烈度Ⅸ度。极震区内地震滑坡、崩塌呈EW向带状分布,并有地裂、泥砂喷发现象发生。主震和主余震的宏观震中区均产生地震断层陡坎。主震断层陡坎最高3.35m,陡坎总长度为1km,陡坎走向为N65°E~N80°E,主震断层以逆推为主,并兼有右旋扭动。地震断层自南向北逆冲的水平距离是2m左右。主余震断层陡坎长3km,走向N65°W,高75cm左右。探槽开挖证实,主余震断层产状为N72°W/192°∠10°,地震时由南向北逆冲的水平距离是1m。Ⅶ度以上等烈度线特征、地震地表破裂和震源机制解结果三者有关地震断错的结论一致  相似文献   
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