Monte-Carlo 法模拟复杂地形对扩散的影响

不考虑边界层中层结作用，引入Kao得到的复杂地形中的平均流场分布和近十年来PBL实验和理论研究导出的新的湍流统计量参数化关系，本文用Monte-Carlo模式模拟了复杂地形对扩散的影响，结果表明:地形的影响主要是迎风坡抬升和背风坡下沉；陡峭地形和平缓地形的影响不完全相同；在陡峭地形和大的平缓地形的背风坡能够形成空腔区，空腔区内出现闭合的浓度中心，且地形越陡峭，闭合浓度中心的范围越大；大地形对扩散的影响可以掩盖其下风方小地形的影响。     

降水量对红富士果面光洁度的影响

红富士苹果果面光洁度是其商品品质的重要指标。本文通过对翼城县近5年气象资料与红富士苹果果面光洁度的对比分析，找出了影响红富士果面光洁度的关键因子是年内降水量的分布与红富士苹果各物侯期的需水是否相吻合，从而提出了提高红富士果面光洁度的具体措施。     

用非线性近似方法反演单多普勒雷达风场

回顾了近年来由单多普勒雷达观测反演风场的各种方法。这些方法大部分基于线性假设，因此风场的非线性交化经常影响反演结果，使得反演的风场误差增大。我们提出一种以非线性近似理论为基础的反演方法，该方法主要考虑了风场分片光滑的特点并充分利用了雷达的径向风场数据。我们把该方法应用到1998年淮河能量与水循环实验的两个个例中。通过同双多普勒雷达观测的结果比较，发现该方法能反演较高分辨率和淮确性的水平风场，反演的垂直风场也比较合理。     

多普勒平滑伪距在GPS/INS紧耦合导航中的应用

针对GPSINS紧耦合导航中GPS伪距观测值精度较低的问题提出了一种多普勒平滑伪距在GPS/INS紧耦合导航的应用算法 首先给出了GPSINS紧耦合导航详细的动力学模型和观测模型在载波相位平滑伪距的基础上推导了多普勒平滑伪距的具体算法和方差－协方差计算公式并引入遗传算法对平滑因子进行最优估计然后利用实测数据验证了新算法的有效性 结果表明平滑算法能够有效提高伪距观测值的精度从而提高组合导航的定位精度相对于载波相位平滑伪距多普勒平滑伪距的精度略有提高而且多普勒平滑伪距不受周跳的影响算法的效率更高 与此同时伪距观测值精度的提高使其与伪距率观测值精度相当增强了滤波系统的稳定性.     

光滑条件约束下密集等高线识别算法研究

介绍了一种在光滑条件约束下密集等高线的跟踪识别方法,解决了等高线的光滑和保真识别问题。     

关于伊利石结晶度Kübler指数的误差计算

本文讨论了测量Kubler指数时产生的误差来源;提出以统计学方法描述“Strip型”衍射峰的半高宽度及其误差大小;以衍射强度、衍射峰形态与测量条件关系式描述“Digital型”衍射峰半高宽的测量误差大小。并特别提出了数字化衍射仪平滑操作产生的误差原理和总体趋势。提出的原理及公式,不仅适合半高宽的误差计算,也适合于其他衍射参数的分析计算,并可用于数字化光谱分析计算中。     

一种基于DEM的高程最优路径选取算法及其实现

针对当前GIS道路选线缺乏定制化的问题,本文设计并实现了基于DEM的高程最优路径选取算法,该算法将高程作为道路选线因素,以匀坡作为选线标准,采用上下行算法和内分插值算法进行道路选线。基于ArcGIS Engine平台,对设计的算法进行了编程,最终实现了卓呼线的自动选取。实验证明,该算法可以利用DEM格网点高程自动绘制匀坡线,从而生成高程成本最优路径。同时,该算法时间复杂度较低,计算速度快,健壮性良好,运算成果正确,不失为一种快速的道路选线新方法。     

Study of formation boundary and dip attribute extraction based on edge detection technology

In the seismic profile interpretation process,as the seismic data are big and the small geological fea-tures are difficult to identify,improvement of the efficiency is needed.In this study,structure tensor method in computer image edge detection processing is applied into the 2D seismic profile.Coherent attribute is used to extract formation edge.At the same time,extracting the eigenvalues and eigenvectors to calculate the seismic geometric properties which include dip and apparent dip,automatic identification is achieved.Testing the Gaussian kernel function with synthetic models and comparing the coherent attribute and dip attribute extraction results before and after,the conclusion that Gaussian filter can remove the random noise is obtained.     

Enacting immanent potentialities: Tcheb‐tchib strategies at the centre of the urban fringe in Nouakchott,Mauritania

The urban fringe areas of Nouakchott, the capital city of the Islamic Republic of Mauritania, have become virtual epicentres of informal property speculation, as the state‐owned land that people illegally inhabit becomes an increasingly valuable commodity in the wake of urban redevelopment plans and vast infrastructural development projects. By applying ingenious ‘poaching’ strategies based on anticipation, the marginalized, impoverished people inhabiting these areas appropriate and manipulate space in order to survive. In their attempt to counter the state's technologies of governance through what is commonly known as tcheb‐tchib, a form of creative improvisation, they become a driving force in the dynamic and contested reconfigurations of the urban landscape. Based on extended ethnographic fieldwork focusing on the strategies of former nomads who are now sedentarized on the urban fringe, this article conceives large‐scale urban renewal as a dynamic process that generates an emergent space of immanent potentiality that the urban poor attempt to strategically appropriate and enact to make the most of a potentially destructive process.     

Half Smooth Tongue Sole(Cynoglossus semilaevis) Under Low Salinity Stress Can Change Hepatic igf2 Expression Through DNA Methylation

Salinity is a crucial environmental stress that severely affects fish growth and survival.Under environmental stress,DNA methylation plays an important role in gene expression and genome function.To better understand the epigenetic regulation mechanism of igf2 under low salinity stress,we analyzed the DNA methylation at 5’UTR,exon1,intron1,and exon2,and analyzed the relationship of DNA methylation with mRNA abundance as well as the special single CpG sites methylation patterns of igf2 in the liver of half smooth tongue sole under low salinity(15)for 0,7,and 60 d.When exposed to low salinity,DNA methylation at 5’UTR and exon2 remained stable,while it was up-regulated firstly and then down-regulated at exon1 and intron1.Some single CpG sites of igf2 associated with low salinity,and most of these sites with significantly changed methylation levels(P<0.05)are located in intron1 area.The discrepant variation of single CpG sites methylation levels and igf2 expression further revealed that females and males showed different response to low salinity.Remarkably,the 38-CpG site of intron1 servers as a sexual marker.Additionally,our integrative analysis demonstrated that regional DNA of igf2 methylation had highly complex interplay on gene expression.The single CpG sites in intron1 were indispensable epigenetic markers under external environmental stress.Above all,to resist the low salinity stress,half smooth tongue sole liver can regulate the expression of igf2 through methylation of CpG sites in intron1.