Research on seismic performance of shear walls with concrete filled steel tube columns and concealed steel trusses

In order to further improve the seismic performance of RC shear walls, a new composite shear wall with concrete filled steel tube (CFT) columns and concealed steel trusses is proposed. This new shear wall is a double composite shear wall; the first composite being the use of three different force systems, CFT, steel truss and shear wall, and the second the use of two different materials, steel and concrete. Three 1/5 scaled experimental specimens: a traditional RC shear wall, a shear wall with CFT columns, and a shear wall with CFT columns and concealed steel trusses, were tested under cyclic loading and the seismic performance indices of the shear walls were comparatively analyzed. Based on the data from these experiments, a thorough elastic-plastic finite element analysis and parametric analysis of the new shear walls were carried out using ABAQUS software. The finite element results of deformation, stress distribution, and the evolution of cracks in each phase were compared with the experimental results and showed good agreement. A mechanical model was also established for calculating the load-carrying capacity of the new composite shear walls. The results show that this new type of shear wall has improved seismic performance over the other two types of shear walls tested.     

Late Jurassic-Early Cretaceous Northern Qaidam Basin, NW China: Implications for the earliest Cretaceous intracontinental tectonism

Formation of Mesozoic western China, which was dominated by tectonic amalgamation along its southern margin and associated intracontinental tectonisms, holds a key for interpreting the succedent Cenozoic evolution. This paper presents new data including lithology, sedimentary facies, stratigraphic contact, seismic interpretation and paleo-structures within the Upper Jurassic-Lower Cretaceous strata in the northern Qaidam Basin, NW China. These data all account for a contractional tectonic deformation in the earliest Cretaceous. The South Qilian Shan, according to the sedimentary features and provenance analysis, reactivated and exhumated during the deformation, controlling the deposition of the Lower Cretaceous sequences. A simplified model for the Late Jurassic-Early Cretaceous paleogeography and tectonics of the northern Qaidam Basin is accordingly proposed. The results also support a ∼25° clockwise rotation of the Qaidam Basin since the Early Cretaceous and a more accurate Mesozoic evolution process for the basin. This earliest Cretaceous deformation, associated with the reactivation of the South Qilian Shan at the time, are part of the intracontinental tectonisms in central Asia during the Mesozoic, and probably driven by both the closure of the Mongol-Okhostk Ocean to the north and the collision of the Lhasa and the Qiangtang blocks to the south.     

西藏尼木变质岩特征及变质温压条件

出露于雅鲁藏布江缝合带北侧尼木县的变质岩主要由石榴黑云片麻岩和黑云斜长角闪角岩组成.研究表明岩石变质程度达到角闪角岩相-辉石角岩相;石榴子石变斑晶具有生长环带,角闪石均为钙质角闪石,黑云母大多为铁质黑云母和铁叶云母,长石多为更长石和中长石,少量为正长石.利用石榴子石-黑云母温度计、石榴子石-黑云母-斜长石-石英压力计和角闪石-斜长石温度及压力计计算获得石榴黑云片麻岩和黑云斜长角闪角岩的变质温度分别为619 ～661℃,695 ～ 702℃,压力范围分别为1.86～1.94kbar和3.69～4.56kbar.野外和室内研究认为岩石原岩为冈底斯带南缘叶巴组火山岩及其上部沉积岩,岩石经历了高温低压的接触变质作用.结合已有冈底斯带陆缘岩浆活动特征,对变质岩的形成环境和过程进行了反演.     

H020U井钻进所遇问题及处理方法

土耳其贝帕扎里天然碱矿H020U井在造斜钻进和水平钻进过程中遇到井漏、钻头钻遇硅化灰岩层磨损严重、未绕过第一靶点V020而打中套管、井涌、仪器掉入裸眼、钻遇未知溶腔导致顶角下降,方位偏离而导致未直接连通第二靶点等问题。针对这些问题进行了分析,并提出了相应的处理方法,最后成功地使H020U井连通第一靶点V020井和第二靶点V020U井。     

Two New Fossil Lacewing Species from the Middle Jurassic of Inner Mongolia, China (Neuroptera: Grammolingiidae)

Two new species of lacewings are described and illustrated from the Jiulongshan Formation (Middle Jurassic) of Inner Mongolia, China: Leptolingia calonervis sp. nov. and Litholingia ptesa sp. nov. (Grammolingiidae). The species can be distinguished by the following features: the outermost branch of MP2 on the hind wing did not reach the margin of wing in Leptolingia calonervis sp. nov.; the second branch of Rs forked deeply while other branches of Rs forked much later in Litholingia ptesa sp. nov..     

Prophaenognatha, a New Aclopinae Genus from the Yixian Formation, China and Its Phylogenetic Position Based on Morphological Characters (Coleoptera: Scarabaeidae)

Prophaenognatha robusta gen. et sp. nov. (Scarabaeoidea: Scarabaeidae: Aclopinae), the best-preserved aclopine fossil so far, is described and illustrated from the Upper Jurassic–Lower Cretaceous Yixian Formation of the Jehol Biota, western Liaoning Province, NE China. The key to extinct and extant genera of Aclopinae is given and the monophyly of extant and fossil Aclopinae lineages is supported by five character states. The new taxon provides evidence about the evolution of Scarabaeoidea with its phylogenetic position inferred based on 68 morphological characters.     

New Fossil Xyelidae (Insecta, Hymenoptera) from the Yixian Formation of Western Liaoning, China

In this paper one new genus and two new species, Brachyoxyela brevinodia sp. nov. and Brachyoxyela gracilenta sp. nov., in the subfamily Macroxyelinae of the family Xyelidae, are described and illustrated. The specimens were collected from the Yixian Formation, the Upper Jurassic to Lower Cretaceous, of Beipiao City, Liaoning Province, northeastern China. The new genus is established based on the characters that vein Sc meets R only beyond origin of Rs, third antennal segment is almost equal in length to the rest flagellomeres combined, terminal flagellomeres increasingly shortened toward apex, and vein 2r-rs inclined toward the apex of wing.     

长江口东南泥质区百年来稀土元素的组成及控制因素

在210pb定年的基础上,分析了长江口外东南泥质区柱样沉积物稀土元素含量、特征参数分布特征及其与粒径、常量元素等的相关性,探讨了150 a以来稀土元素的来源、制约因素及对沉积环境的响应.结果表明,柱样稀土元素总量(ΣREE)变化范围不大,分布范围为158.38～197.87 μg/g,平均值为183.49μg/g,总体...     

寒冷地区无压输水暗渠运行模型试验研究

根据我国北方寒冷地区某无压输水暗渠工程实际,通过在室内环境箱中进行暗渠比例模型试验,研究暗渠在冬季输水过程中水流温度受外界环境温度、流速及进水口水温的影响.通过改变试验条件,研究了暗渠模型内水流温度降低与外界环境温度、水流流速及进水口水温的关系.经过数据拟合,得到暗渠水流温度与环境温度、水流流速及进水口水温的回归公式,...