基于非平稳随机地震动模型的重力坝抗震可靠度分析

基于正交展开的非平稳随机地震动模型,并考虑混凝土材料的非线性和坝体与库水之间的流固耦合,对印度Koyna重力坝进行有限元分析,得到坝顶水平位移和坝颈拉应力,结合概率密度演化方法和等价极值事件的思想,获得丰富的概率信息。这为坝体结构的随机地震反应分析和可靠度研究提供新的途径。     

A thermostable serralysin inhibitor from marine bacterium Flavobacterium sp. YS-80-122

Serralysin inhibitors have been proposed as potent drugs against many diseases and may help to prevent further development of antibiotic-resistant pathogenic bacteria. In this study, a novel serralysin inhibitor gene, l up I, was cloned from the marine bacterium F lavobacterium sp. YS-80-122 and expressed in Escherichia coli. The deduced serralysin inhibitor, Lup I, shows 40% amino acid identity to other reported serralysin inhibitors. Multiple sequence alignment and phylogenetic analysis of Lup I with other serralysin inhibitors indicated that Lup I was a novel type of serralysin inhibitor. The inhibitory constant for Lup I towards its target metalloprotease was 0.64 μmol/L. Lup I was thermostable at high temperature, in which 35.6%–90.7% of its inhibitory activity was recovered after treatment at 100°C for 1–60 min followed by incubation at 0°C. This novel inhibitor may represent a candidate drug for the treatment of serralysin-related infections.     

先验形状约束的水平集分割模型

传统C-V模型只利用了图像的灰度信息,分割精度不高。本文凭借水平集理论在拓扑结构优化及形状建模方面的优势,以普遍类型的规则建筑物为例,研究如何将人的先验知识融合至水平集框架中,并提出先验形状约束的建筑物目标分割模型,以改善高分辨率遥感影像中建筑物受干扰情况下分割的完整性及准确性。试验证明,该模型分割结果较C-V模型有很大提高,基本能保持与eCognition多尺度分割相近的精度。     

鹫峰地区QuickBird影像纹理特征与生物量估测关系初探

以北京鹫峰地区为研究区,探索QuickBird影像纹理特征与地上乔木层生物量间的关系。基于灰度共生矩阵纹理分析方法,按照不同窗口大小(3*3,5*5,9*9,15*15,21*21)分别提取QuickBird影像多光谱和全色波段的8个纹理特征值。利用皮尔森相关系数衡量纹理特征与地上乔木层生物量间的相关性,研究表明:多光谱波段的大多数纹理特征值与生物量的相关性很低,但是全色波段的大多数纹理特征值与生物量的相关性较高。相比之下,QuickBird多光谱波段和全色波段的光谱特征值与生物量的相关性都较低,这表明,QuickBird全色波段某些纹理特征值可能在提高生物量估测方面起决定性作用。     

四川省洪雅县地质灾害发育特征及影响因素分析

在实际调查基础上,通过分析洪雅县地质灾害的发育分布特征认为地层岩性、地质构造和地形地貌是县内地质灾害发生的主要控制因素,持续降雨和不合理人类工程活动是地质灾害的主要引发因素.     

基于改进层次分析法的GIS公共服务设施选址

已有的公共服务设施选址模型较复杂且应用范围受限,无法作为通用模型出现。层次分析法可作为选址的通用模型,但单独使用层次分析法在空间分析方面仍有欠缺,单纯的GIS在复杂指标权重的处理方面存在很大不合理性。该文对层次分析法进行了改进,使之更适用于GIS的数据结构,将改进的层次分析法与GIS技术结合,成为公共服务设施选址更合理的选址模型和方法。以河北省黄骅市中学选址为例验证模型和方法的可用性。     

1961～2008年山东省极端降水事件的变化趋势分析

利用山东省1961～2008年逐日降水资料,采用百分位值法定义了极端降水事件的阈值,然后统计出极端降水事件的频次、降水量、强度和年最大日降水量,并对其空间分布和时间趋势进行分析。结果表明,山东省极端降水事件阈值的空间分布存在明显的地域差异,总体上以泰山为中心向周边逐渐减小;频次的空间差异较小,基本在18 d/a左右;极...     

社会主义宪法应该代表先进生产力的发展要求

根据“三个代表”的思想，社会主义宪法应该代表先进生产力的发展要求，中国的宪法发展说明，什么时候代表了中国先进社会生产力发展的要求，什么时候中国宪法就能健康发展。     

An Efficient Hydrodynamic Model for Surface Waves

In the present study,a semi-implicit finite difference model for non-bydrostatic,free-surface flows is analyzed and discussed.The governing equations are the three-dimensional free-surface Reynolds-averaged Navier-Stokes equations defined on a general,irregular domain of arbitrary scale.At outflow,a combination of a sponge layer technique and a radiation boundary condition is applied to minimize wave reflection.The equations are solved with the fractional step method where the hydrostatic pressure component is determined first,while the non-hydrostatic component of the pressure is computed from the pressure Poisson equation in which the coefficient matrix is positive definite and symmetric.The advectiou and horizontal viscosity terms are discretized by use of a semi-Lagrangian approach.The resulting model is computationally efficient and unrestricted to the CFL condition.The developed model is verified against analytical solutions and experimental data,with excellent agreement.