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The 5‘-end of the mitochondrial control region sequences of three flatfishes (Pleuronectiformes: Pleuronectidae) were amplified and sequenced. These sequences were compared with those of other three Pleuronectids species retrieved from GenBank. A phylogenetic tree was constructed based on the partial control region sequences. The results of phylogenetic analysis are consistent with those of conventional systematics. Compared to previous studies, the structure of the 5‘-end of mitochondrial control region was analyzed. The terminal associated sequence motif and its complementary motif were identified at the 5‘-end of the sequences. A conserved sequence block, named as CM5‘ d, was identified in the 5‘-end of control region sequences in all Pleuronectids. Another central conserved sequence block, named as CSB-F, was detected in the central conserved blocks.  相似文献   
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顺煤层断层的基本特征及其地质意义   总被引:40,自引:1,他引:40  
曹运兴  彭立世 《地质论评》1993,39(6):522-528
顺煤层断层是指顺煤层发育的断面与煤层层面的交角较小或近于平行的断层。它的主要识别标志是断层面、构造煤和煤层厚度的强烈变化。顺煤层断层可独立存在,也可与其它地质构造相互转换,相伴出现。顺煤层断层具有特殊的选层性,这一特征与煤体较低的力学强度、煤层瓦斯压力及形变期顺煤层的剪切作用有关。顺煤层断层在煤田中分布广泛,它所产生的构造煤是瓦斯高聚集区,亦是瓦斯突出的危险区,其研究意义重大。  相似文献   
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小兴安岭-张广才岭成矿带位于华北克拉通北缘东北段、中亚造山带东南段和西环太平洋外带交汇部位,经历了多期次的叠加改造运动,使得该区成为研究大陆造山带地质构造演化、地质构造域转换以及构造作用叠合成矿的理想区域.本文选择小兴安岭-张广才岭成矿带南段的福安堡钼矿区的二长花岗岩和花岗闪长岩进行岩石学、LA-ICP-MS锆石U-P...  相似文献   
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太原基准地震台数字化形变观测仪器伸缩仪和体应变仪记录的分钟值固体潮曲线上叠加有锯齿状的高频干扰,为探寻干扰源,对附近的抽水井、高压输电线、溶洞及煤矿进行调查分析,发现其对观测仪器的影响均不明显,认为与山洞下面可能存在的裂隙带有关。  相似文献   
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Smoothed particle hydrodynamics(SPH) is a mesh-free adaptive Lagrangian particle method with attractive features for dealing with the free surface flow.This paper applies the SPH method to simulate the large-amplitude lateral sloshing both with and without a floating body,and the vertical parametrically-excited sloshing in a two-dimensional tank.The numerical results show that the SPH approach has an obvious advantage over conventional mesh-based methods in handling nonlinear sloshing problems such as violent fluid-solid interaction,and flow separation and wave-breaking on the free fluid surface.The SPH method provides a new alternative and an effective way to solve these special strong nonlinear sloshing problems.  相似文献   
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I. INTRODUCTIONSumming up recent research achievements, Huang (1993) pointed out that the capaciucs ordetachment and transport by rill now were much greater than tboso by rain drop impact and sheet now. soil erosion by water on upper slope area is frcquenhy discussed interms of interrill and rill erosional sub--processes. Compared with rill erosion, interrlll erosion contributes a very small proportion to the sediment transported downwards (Foster,1982). Field experiments conducted by Ca…  相似文献   
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基于取淡与流量控制的压咸调度方案研究   总被引:1,自引:0,他引:1  
刘斌  刘丽诗  吴炜  闻平  黄宇铭 《水文》2013,33(4):84-86
珠江三角洲素有"三江汇流、八门出海"之称,河网、河口系统之复杂在世界上首屈一指,咸潮活动也因复杂的水动力系统表现出异于世界其他河口的特点。同时,珠江三角洲人口众多、经济活动活跃,受咸潮影响人口超过1 000万人、取水规模超过1 000×104m3/d。为此,珠江防总从2005年起已连续8次实施了水量调度,提出了梧州压咸流量不低于1 800 m3/s的单一控制指标,保障了供水安全。在8次水量调度的基础上,根据咸潮与径流、潮汐的响应关系,分3个流量级提出了基于平岗泵站和联石湾水闸取淡目标的西江北江压咸补淡调度方案。  相似文献   
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