大矢高脊线式叉筒网壳静力及抗震性能分析

运用ANSYS软件对大矢高脊线式叉筒网壳结构进行系统的静力性能分析,详细研究了结构跨度S、矢高f、环向区域份数Kn、径向节点圈数nx对结构静力性能的影响;在此基础上对结构进行自振特性分析和地震响应分析。探讨了跨度、矢高对结构基频的影响规律,及结构环向区域份数、径向节点圈数对结构震后最大位移的影响规律。研究结果表明:大矢高脊线式叉筒网壳静力性能良好,矢高对结构静力性能影响不大,环向区域份数、径向节点圈数对结构静力性能影响较复杂;结构自振频率分布和振型有很强的规律性,结构基频对跨度较敏感;结构抗震性能优越,结构环向区域份数对结构震后最大位移影响较大。     

微量硼对形变TiAl

以形变     

水平井产能预测相关式研究

针对水平井的稳态产能预测误差较大的问题,通过半解析耦合模型计算对比,发现在不同泄油体形态、水平垂直渗透率各向异性条件下,Joshi公式的误差变化规律：在厚油层、低垂向渗透     

开圆孔波纹腹板钢梁弹性抗剪屈曲

进行了开有圆孔的波纹腹板钢梁腹板的弹性抗剪屈曲研究.建立了有限元模型,通过特征值屈曲分析得到弹性屈曲荷载.探讨了开孔腹板弹性屈曲应力与孔径大小、腹板高度、腹板厚度、开孔的横向偏心以及纵向偏心的关系.在已有的未开孔波纹腹板受剪屈曲承载力计算公式的基础上,通过大量的有限元数值计算,分析了各参数的影响,以折减系数的形式得到开孔后的弹性抗剪屈曲承载力计算公式.     

Unique astrocyte ribbon in adult human brain contains neural stem cells but lacks chain migration

The subventricular zone (SVZ) is a principal source of adult neural stem cells in the rodent brain, generating thousands of olfactory bulb neurons every day. If the adult human brain contains a comparable germinal region, this could have considerable implications for future neuroregenerative therapy. Stem cells have been isolated from the human brain, but the identity, organization and function of adult neural stem cells in the human SVZ are unknown. Here we describe a ribbon of SVZ astrocytes lining the lateral ventricles of the adult human brain that proliferate in vivo and behave as multipotent progenitor cells in vitro. This astrocytic ribbon has not been observed in other vertebrates studied. Unexpectedly, we find no evidence of chains of migrating neuroblasts in the SVZ or in the pathway to the olfactory bulb. Our work identifies SVZ astrocytes as neural stem cells in a niche of unique organization in the adult human brain.     

辽中凹陷东营组重力流发育机制及沉积构成

辽中凹陷锦州区块东营组发育三角洲滑塌浊积扇、远岸水下扇和近岸水下扇等重力流沉积。在高分辨率层序地层划分和对比的基础上,通过区域沉积体系分析,探讨了各类水下重力流沉积的形成条件,建立了相应的发育模式,分析认为：物源系统、坡折类型和湖平面变化的耦合关系决定着沉积体的基本特征,包括类型、层序位置、发育部位和规模大小等。进一步研究表明,各类重力流沉积内部构成差异明显,坡折类型及组合样式对其控制作用明显,表现为：坡折组合的规模和复杂状况决定了砂体平面展布的分异状况;坡折带的类型和坡度决定着沟道体系的发育情况;坡折下方微地貌构建的次级坡折带控制着砂体的分配,尤其是优质砂体的富集位置。沟道化是断陷湖盆重力流沉积的一大特色,探讨了其有别于经典海相重力流相模式的原因。对岩性圈闭的勘探有一定的借鉴意义。     

考虑热损失非牛顿稠油热采不稳定试井分析

针对蒸汽未波及区的油层没有得到有效改善这一问题,通过采用内区考虑热损失,外区考虑为非牛顿幂律流体复合模型分析,求得了无限地层情况下的拉氏空间解。通过数值反演方法作出了相应的样版曲线,并且对样版曲线作了相应的敏感性分析。新的样版曲线在非牛顿流的影响下有别于常规复合油藏,外区径向流段不再呈现一般的水平直线段,在交界处由于冷凝系数的影响,压力导数出现明显的下掉现象,冷凝系数越大,下掉越严重。为稠油开发油藏压力动态分析提供了一种新的模型。     

The unusual γ-ray burst GRB 101225A from a helium star/neutron star merger at redshift 0.33

Long γ-ray bursts (GRBs) are the most dramatic examples of massive stellar deaths, often associated with supernovae. They release ultra-relativistic jets, which produce non-thermal emission through synchrotron radiation as they interact with the surrounding medium. Here we report observations of the unusual GRB 101225A. Its γ-ray emission was exceptionally long-lived and was followed by a bright X-ray transient with a hot thermal component and an unusual optical counterpart. During the first 10 days, the optical emission evolved as an expanding, cooling black body, after which an additional component, consistent with a faint supernova, emerged. We estimate its redshift to be z = 0.33 by fitting the spectral-energy distribution and light curve of the optical emission with a GRB-supernova template. Deep optical observations may have revealed a faint, unresolved host galaxy. Our proposed progenitor is a merger of a helium star with a neutron star that underwent a common envelope phase, expelling its hydrogen envelope. The resulting explosion created a GRB-like jet which became thermalized by interacting with the dense, previously ejected material, thus creating the observed black body, until finally the emission from the supernova dominated. An alternative explanation is a minor body falling onto a neutron star in the Galaxy.     

基于光流块统计特征的视频异常行为检测算法

提出了一种基于光流块统计特征的视频异常行为检测算法.该算法首先对训练集视频序列的光流场进行分块及预处理,而后提取光流块的统计特征,所提取的块统计特征同时包括了光流块的幅度信息和相位信息,通过训练集得到的光流块统计特征训练出对应的正常行为的高斯混合模型(GMM).测试集通过同样的方式提取光流块统计特征,通过计算所提取统计特征以多大的概率属于GMM判定所检测光流块的异常程度.实验结果表明,该算法能够在一定程度上解决运动物体一致性和部分遮挡问题,并提高了异常行为检测的准确率.