波前相位差法探测器的设计

波前相位差法是利用焦面像和离焦面像通过一个相位多样性算法来拟合相位或对目标复原,这就要求采集两个图像,一个是焦面像,另一个是离焦面像。本文的设计是根据晶体的偏振原理分像,并将焦面像和离焦像同时采集到同一个CCD(Charge Coupled Device)上,这种方法保证了两个图像的同步、实时,而且光学系统简单。文中具体给出了一种新型波前相位差法探测器的设计方案、像差分析,并且模拟了波前相位差法探测器对模拟结果的影响。     

Devonian alkaline magmatism in South Qinling,China: evidence from the Taohekou Formation,Northern Daba Mountain

The Langao area in South Qinling consists of a poorly dated sequence of volcano-sedimentary units (Taohekou Formation). This study focuses on volcanic edifice of Taohekou Formation. Detailed field mapping, section facies analysis, geochemistry, and Ar–Ar geochronology is presented here to develop a more accurate understanding of the tectonic evolution of the Qinling Orogen. Detailed field mapping and section facies analysis reveals the presence of a seamount volcanic edifice in western Xiaozhen area. Ar–Ar dating of alkaline basalts in the sequence indicates an Early Devonian magmatic age. Whole rock geochemistry of these alkaline basalts indicates that both potassic and sodic basalts were erupted respectively in the eastern and western areas. Both types of samples are typically characterized by high concentrations of TiO₂, Nb, Ta, and Zr. Ocean-island basalt (OIB)-like rare earth element distribution patterns, trace element spider diagrams, and similar Sr and Nd isotopic compositions (i.e. relatively low Sr and moderate Nd isotopic ratios) likely indicate that the samples were comagmatic but have experienced varying degrees of fractional crystallization. In addition, the samples appear to have all originated from the asthenospheric mantle and undergone mantle metasomatism, ultimately resulting in an OIB-type provenance. Most importantly, in combination with its regional tectonic evolution, the Taohekou Formation is constrained to a seamount environment. This formation does not represent a plume but, rather, an extensional fracture zone related to subduction. Thus, this geologic interpretation generates pivotal evidence for accurately investigating the properties and temporal constraints of the Mianlue oceanic basin.     

腾冲热海地区NW向断裂活动性的地球化学证据

腾冲热海是中国最著名的火山地热区 ,近期区内水热流体活动异常强烈。研究区内几乎所有 95℃以上的沸泉、喷沸泉以及 1993年以来发生的 2 0余次水热爆炸点均沿NW向断裂分布 ,显示该断裂目前处于强烈活动之中。钍、氡射气测量结果确定了NW向断裂的存在和具体位置。研究认为 ,NW向断裂的形成和异常活动可能与火山区壳内岩浆活动有关     

三江并流带丹霞地貌景观地质成景作用

本分析对比了三江并流带黎明、罗古箐、石宝山三个丹霞地貌发育地区的景观特征,从地质学与岩石学的角度分析典型丹霞地貌景观的成景地质条件,探讨景观的地质成景作用,总结景观的成景过程。研究认为,三江并流带丹霞地貌具有自身独特的特征,岩性和构造差异是不同丹霞地貌景观差异形成的根本原因;峰林景观差异因岩层厚度、节理发育程度、交错层理不同而不同;丹霞峰林或赤壁上的“变色瀑布”是裂面或层面之间岩层水渗出沿壁下淌的结果;龟裂纹景观形成严格受岩性和节理构造控制,其发育经过了成景初期、成景中期、成景晚期三个阶段。     

Analysis on the Regional Features of Coda Attenuation Before and After the 1992 Qina (M_S= 5.4, 5.1) Earthquakes in WYEPSA

Using the theoretical model of coda scattering from local earthquakes, we have studied the features of time-space variations of the attenuation rate β of coda amplitude and coda Qc-1 values before and after the Qina earthquakes (MS5.4 and MS5.1) in Dec. 1992 in West Yunnan Earthquake Prediction Study Area (WYEPSA). The study results show that the attenuation rate of coda amplitude has remarkable regional inhomogeneity in the near-field (△ <50 km) around the main shock: β = 0.0076 s-1 and Qc-1 = 0.0056 during the main shock while (3 = 0.0209 s-1 and Qc-1 = 0.0153 during the aftershock. The Qc-1 value shows an approximate 3-foid variation before and after the main shock. We have also obtained the regional averages of β = 0.0235 s-1 and Qc-1 = 0.0153, which show that the coda attenuation in surrounding areas (△ > 50 km) far away from the epicenter of the main shock did not change much before and after the main shock. The evolution of Qc-1 values of the main seismic sequence with time has passed throug     

Mutation Anomalies of the Wave Velocity Ratio at a Single Station Before the Lancang-Gengma Earthquake

In this paper,the process of dynamic variation of the wave velocity ratio that occurred at a single station,such as Lancang,Tengchong,and Eryuan stations,8 years before the Lancang-Gengma earthquakes(Ms=7.6 and 7.2),is studied by applying the synthetic method as a whole.It is found that the moderately strong and strong earthquakes 250 km away that occurred since 1983 may lead to mutation anomalies of the wave velocity ratio in the Lancang region.The mutation amplitude is increased with the approaching time and distance of a large event.The reliability of mutation data for the wave velocity ratio has been demonstrated in many ways.The application of mutation of the wave velocity ratio to earthquake prediction and its physical explanation are discussed.     

Baiyun Cave in Naigu Shilin,Yunnan Karst,China

The Baiyun cave is a 380 m long karst cave in the Naigu Shilin, situated 70 km southeast of Kunming, Yunnan Province, China. The prevailing orientations of the cave passages are N110°-120°E and N0°-10°W and those of the fissures in the cave are N30°-40°W and N20°-30°W. The cave is developed in the thick-bedded Lower Permian Qixia Formation. The cave has an active water flow and is currently at the near water-table stage. There are large amounts of different infills of cave sediments. The cave shows different stages of paragenesis. The palaeomagnetic analysis of cave sediments shows that their ages are younger than 780 ka B.P. (the Brunhes Chron). The upper part of the sampled profile belongs to the reverse Blake event (112.3-117.9 ka B.P.). The formation of the Baiyun cave is directly connected with the development of the Naigu Shilin. The formation of karst underground and surface features depends on the regional tectonic deformation and the Cenozoic extension of the study area.     

New Early Cambrian Chordates from Haikou, Kunming

Two new chordates, Cathaymyrus haikouensis Luo et Hu sp. nov. and Zhongxiniscus intermedius Luo et Hu gen. et sp. nov. are studied in this paper. Both display numerous S-shaped myomeres on their trunk. C. haikouensis shows a long and slim body similar to that of Cathaymyrus diadexus Shu et al., Zhongxiniscus approaches to Myllokunmingia and Haikouichthys in the dorsal fin, but differs in the myomeres. Zhongxiniscus may be the intermediate form between Cathaymyrus and Myllokunmingia and Haikouichthys.     

滇中鱼坝村组的建立及陆相侏罗系底界

滇中及相邻地区上三叠统舍资组含煤层与下侏罗统冯家河组红层之间，连续沉积了一套杂色细碎屑岩过渡层。其分布稳定，该层所含化石及磁性地层特征表明其时代属早侏罗世。因此建立下侏罗统鱼坝村组，并确定该组底界为陆相侏罗系的底界。     

腾冲火山地热区地壳结构的地震学研究

根据腾冲火山地热区实施的人工地震测深剖面资料 ,用有限差分反演和正向走时拟合方法确定了地壳二维 P波速度结构 .地壳模型显示 ,在腾冲的热海热田附近上地壳存在低速异常体 ,它与火山地热活动可能有关 .测线的二维地壳结构上显示出两条地壳断裂 :龙陵—瑞丽断裂和腾冲断裂 ,其中腾冲断裂可能切穿莫霍界面 .同时 ,根据远震波形资料反演腾冲热海热田地区的 S波速度结构 ,也显示出该地区上地壳存在 S波的低速异常 .本文从深部结构方面探讨腾冲火山的成因 .腾冲火山地热区地壳具有低 P波和 S波速度、低电阻率、高热流值和低 Q值 ,以及上地幔也具有低 P波速度的特点 .由此推测地壳内岩浆来源于上地幔 ,腾冲附近地区存在的上地壳低速度异常可与岩浆的分异作用相联系 .与地球上大多数的活动火山一样 ,腾冲火山位于移动板块之间的边界附近 ,属于“板块边界”火山