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51.
This paper reports two species of the family Pyramidellidae (Gastropoda, Heterobranchia), Otopleura nitida (A. Adams, 1854) and Rugadentia manzakiana (Yokoyama, 1922). The former was from the South China Sea and the latter was from the Yellow Sea and East China Sea. The study was based on the collections deposited in the Marine Biological Museum, Chinese Academy of Sciences. This is for the first time that these species have been recorded in China seas. In the current contribution, we describe and illustrate these two species, and compare them with similar species.  相似文献   
52.
低信噪比转换波地震资料静校正(英文)   总被引:1,自引:0,他引:1  
Converted waves have slow velocity and low signal-to-noise ratio. It is also difficult to pick first-breaks and bin the common-conversion-points (CCP). Some statics methods, which work well for P-wave data, can't be effectively used for solving convertedwave statics problems. This has become the main obstacle to breakthroughs in convertedwave data processing. To improve converted-wave static corrections, first, a statics method based on the common-receiver-point (CRP) stack is used for the initial receiver static correction to enhance the coherency of the CRP stack. Second, a stack-power-maximization static correction which improves the continuity of the CCP stack is used for detailed receiver statics. Finally, a non-surface-consistent residual moveout correction of the CCP gathers is used to enhance the stack power of reflection signals from different depths. Converted-wave statics are solved by the joint use of the three correction methods.  相似文献   
53.
This paper analyzes the distribution characteristics of geomagnetic low-value displacement in Gansu and its adjacent areas from 1995 to 2003 on the basis of the data of the daily amplitude minimum value time of the geomagnetic vertical component. It is shown that in addition to the changing rules of geomagnetic low-value displacement itself, there is a better correlation between geomagnetic low-value displacement and the occurrence of moderately strong earthquakes. There appeared to be geomagnetic low-value displacement before the moderately strong earthquakes in Gansu in the 9 years from 1995 to 2003. This result indicates that geomagnetic low-value displacement is of instructive significance for earthquake prediction to some extents.  相似文献   
54.
EOF-CCA模型在山东季降水预测中的应用   总被引:4,自引:1,他引:3  
胡桂芳  张苏平  谢考宪 《气象》2000,26(7):12-16
首先介绍了EOF-CCA模型的基本原理及建模步骤,阐明了经验正交函数分解(EOF)和典型相关分析(CCA)两种统计方法在短期气候预测应用中结合的必然性及优越性,并指出该模型可由一个气候场或多个气候场去预报另一个气候场。然后以山东13站的报隆水量场为预报场,分别以前期整个北半球和东亚区域的500hPa月平均们势高场为因子场,建立了位势高度场的前13个主分量场与季降水场之间的EOF-CCA模型,最后对  相似文献   
55.
采用室内池子多层笼养殖方式 ,以加工海带、鲜江艹离 与 A,B2种片状饲料为饵料 ,试验了不同食物与不同放养水层对九孔鲍生长影响 ,结果表明 :( 1)从壳长增长上 ,海带与饲料 B近似 ,各为 11.3与 11.2 mm;其次为饲料 A,10 .2 mm;而江 艹离 最差 ,仅 7.7mm;( 2 )在体重增长上 ,以饲料 B最高 ,平均每只为 3.3g,其次为饲料 A与海带 ,平均每只 2 .9g,而江艹离 仅 1.8g;( 3)从试验期间所获体重增长比壳长增长看 ,两种饲料 ( B为 2 95,A为 2 84 mg/mm)均比两种海藻高 (海带为 2 57,江艹离 为 2 34mg/mm) ;( 4 )从垂直 11层笼子九孔鲍生长的比较 ,下层的好于上层 ,越是下层越好 ,投喂两种饲料在体重上差别更明显。  相似文献   
56.
基于地震的发生与断裂的活动性密切相关,为了科学合理并尽可能准确地判定未来地震重点危险区域,以安徽为例,利用由深浅部对比、宏微观构造解析所给出的新生代构造活动性最新研究成果,结合地震活动性资料研究结果,对一些重点部位的地震危险性进行了综合研究。结果表明,根据长时间尺度的地质构造最新研究揭示的活动性较强区域,与根据近代地震活动性资料研究反映的危险性较大区域,呈现较好的一致性特征,从而为未来地震重点危险区域的判定提供了新的较为可靠的依据和方法。  相似文献   
57.
The results obtained in this paper indicate that carbazole-type compounds have high thermal stability and also show stability in oxidation and bio-degradation. This kind of compounds still has a high concentration and complete distribution in the analyzed dry asphalt samples, showing that they are particularly useful in studying petroleum migration of paleo-pool. During the basin's first-stage of oil-gas pool formation in the Silurian in Tazhong and Tabei areas of Tarim Basin (at the end of Silurian period) and the second-stage in the Awati area (in Permian), the petroleum experienced a long-distance migration. During the formation of the Silurian paleo-pools in Tazhong Uplift at the end of Silurian, the petroleum mainly came from the lower and middle Cambrian source rocks in the Manjiaer sag. The petroleum migrated towards the southwest-south entering the Silurian reservoir beds in Tazhong first. Then, it further migrated within Silurian from northwest to southeast along the highs of the Structural Belts to the region of the Silurian pinchout boundary in Tazhong. In Tabei Uplift, during the first-stage of pool formation, the petroleum was also from the lower and middle Cambrian source rocks in the Manjiaer sag. It migrated northwest entering the Silurian reservoir beds in the Tabei Uplift firstly, and then the migration continued in the same direction within the Silurian reservoirs and finally the petroleum was trapped in higher positions. During the second-stage pool formation in the Silurian beds in the areas around Awati sag, the petroleum mainly came from the lower-middle Cambrian source rocks in the Awati sag. The petroleum migrated from the generation center to Silurian reservoirs in all directions around the sag through major paths, and the petroleum was finally trapped in higher locations.  相似文献   
58.
The sedimentary environments are the intrinsic factor controlling the mechanical properties of clastic rocks. Examining the relationship between rock sedimentary environments and rock mechanical properties gives a better understanding of rock deformation and failure mechanisms. In this study, more than 55 samples in coal measures were taken from seven different lithologic formations in eastern China. Using the optical microscope the sedimentary characteristics, such as components of clastic rocks and sizes of clastic grains were quantitatively tested and analyzed. The corresponding mechanical parameters were tested using the servo-controlled testing system. Different lithologic attributes in the sedimentary rocks sampled different stress–strain behaviors and failure characteristics under different confining pressures, mainly due to different compositions and textures. Results demonstrate that clastic rocks have the linear best-fit for Mohr-Coulomb failure criterion. The elastic moduli in clastic rocks are highly dependent upon confining pressures, unlike hard rocks. The envelope lines of the mechanical properties versus the contents of quartz, detritus of the grain diameter of more than 0.03 mm, and grain size in clastic rocks are given. The compressive strength or elastic modulus and the grain diameter have a non-monotonic relation and demonstrate the “grain-diameter softening” effect.  相似文献   
59.
采用染色薄片鉴定、阴极发光显微镜观察、微量元素分析、碳氧稳定同位素测定及包体侧温等手段,对塔里木盆地巴楚断隆区寒武系和奥陶系白云岩的特征及成因进行了研究,共划分出四种类型的白云岩:①泥粉晶白云岩,其m(Ca)/m(Mg)平均为3-10,Sr含量高(>300×10-6 ),m(Sr)/m(Ba)>>1,?13C值较高(-1‰-+1‰),18O值较低(-5‰--8‰),沉积环境为潮上带云坪,为准同生作用阶段潮上萨布哈白云化作用形成。②含雾心亮边白云石的细晶白云岩,其m(Ca)/m(Mg)较低(1-2),Sr含量中等(100×10-6-200×10-6),m(Sr)/m(Ba) >1,?13C值在-2‰左右,18O值低,在-7‰左右,沉积环境为开阔台地浅滩,为准同生或早期成岩作用阶段回流渗透白云化作用形成。③含明亮白云石晶体及钙质残余的钙质白云岩,其m(Ca)/m(Mg)较低(1左右),Sr含量最低(100×10-6左右),m(Sr)/m(Ba) < 1,?13C值最低(-1‰--3‰),?18O值较低(-6‰左右),沉积环境为灰坪、云坪及开阔台地,为准同生或早期成岩作用阶段混合水白云化作用形成。④砂糖状白云岩,其m(Ca)/m(Mg)较低(1-2),Sr含量低(<100×10-6),m(Sr)/m(Ba)<1,?13C值较高(-1‰-+3‰),18O值较低(-5‰--8‰),沉积环境多为浅滩,为晚期成岩作用阶段埋藏白云化作用形成。  相似文献   
60.
青藏高原东北缘贵德坳陷发育一套烃源岩,长期以来,其时代归属不统一,其生烃能力认识不清,制约了该坳陷油气资源勘探的进程.本文通过野外踏勘、露头剖面实测和样品分析及连续电磁剖面(CEMP)测量结果得出以下认识:①根据沉积特征及孢粉组合,结合区域地质资料,确定了该套地层形成时代为早白垩世,沉积环境为浅湖—半深湖;②借助野外实测剖面及连续电磁剖面(CEMP)资料,确定了该套烃源岩的发育规模;③通过对剖面样品的有机质丰度、热演化程度等实验分析,对该套烃源岩的油气勘探潜力进行了综合评价,认为该套烃源岩分布范围广,厚度大,有机质丰度高,热演化程度适中,可以作为贵德坳陷的有效烃源岩,提升了贵德坳陷油气勘探潜力;④利用野外调查结果及连续电磁剖面(CEMP)资料对贵德坳陷生储盖组合进行综合分析,并指出了有利的勘探方向.  相似文献   
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