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101.
102.
Juan Ignacio Soto 《Mathematical Geology》1997,29(1):93-130
A deformation that is obtained by any simultaneous combination of two steady-state progressive deformations: simple shearing
and a coaxial progressive deformation, involving or not a volume change, can be expressed by a single transformation, or deformation
matrix. In the general situation of simple shearing in a direction non-orthogonal with the principal strains of the coaxial
progressive deformation, this deformation matrix is a function of the strain components and the orientation of shearing. In
this example, two coordinate systems are defined: one for the coaxial progressive deformation (xi system), where the principal and intermediate strains are two horizontal coordinate axes, and another for the simple shear
(x
i
t’
system), with any orientation in space. For steady-state progressive deformations, from the direction cosines matrix that
defines the orientation of shear strains in the xi coordinate system, an asymmetric finite-deformation matrix is derived. From this deformation matrix, the orientation and
ellipticity of the strain ellipse, or the strain ellipsoid for three-dimensional deformations, can be determined. This deformation
matrix also can be described as a combination of a rigid-body rotation and a stretching represented by a general coaxial progressive
deformation. The kinematic vorticity number (W
k is derived for the general deformation matrix to characterize the non-coaxiality of the three-dimensional deformation. An
application of the deformation matrix concept is given as an example, analyzing the changes in orientation and stretching
that variously-oriented passive linear markers undergo after a general two-dimensional deformation. The influence of the kinematic
vorticity number, the simple and pure shear strains, and the obliquity between the two deformation components, on the linear
marker distribution after deformation is discussed. 相似文献
103.
山区开矿和城镇建设使毛木耳资源日益匮乏,为了合理保护利用毛木耳资源,为新品种选育提供理论依据。也为毛木耳DNA指纹图谱的构建奠定基础,从分子水平上探讨毛木耳种间、品种间遗传关系,用ISSR标记分析毛木耳种质资源。结果表明:从27条ISSR引物中筛选出适合毛木耳种质分析的17个ISSR引物。17个引物共扩增出155条带,多态性位点155;多态性位点比率100%。基于扩增条带数据库建立了Jaccared遗传相关系数矩阵。构建了相似的分子树状图,将55个供试菌株分为5类群:Ⅰ类群含12个菌株,Ⅱ类群含11个菌株,Ⅲ类群含2个菌株,Ⅳ类群含24个菌株,Ⅴ类群含6个菌株。55个菌株的平均遗传相似系数为0.4109。同时类群的划分与菌株来源的地理分布没有关系。菌株间的遗传多样性十分丰富。用ISSR标记技术能将以传统形态特征为分类依据定名的菌株全部分开。 相似文献
104.
1 Introduction As a linkage between the biosphere and the geosphere, organic geochemistry, especially molecular markers, has become a powerful tool for investigating important geological events and the evolutionary history of ancient life on Earth (Kvenvo… 相似文献
105.
针对道路高精度地图采集中道路标识线快速分类提取问题,提出了一种根据几何结构特征对道路标识线进行自动匹配提取的方法。首先利用点云生成强度特征图像,并根据点云密度分布特征将强度特征图像划分为多个区域;然后对每个区域进行二值化处理;最后考虑路面标识线缺失情况,设计了一种多约束条件的几何特征语义识别模型,实现了不同标识线类型的分类。对车载移动测量系统获取的多段道路点云数据进行实验,结果表明,该方法的道路标识线提取准确率和识别准确率分别为90.01%和82.83%,总体精度达到86.27%。 相似文献
106.
刘果 《测绘与空间地理信息》2015,(4):174-176
在GIS系统应用中,经常遇到海量空间点数据的显示问题,若要显示全部空间点,采用传统的方法速度慢且压盖严重。近年出现的聚合显示技术,较好地解决了显示速度和可读性的问题,但这种聚合显示算法存在缺陷,不能很好地按分布的密度来进行聚合点的显示,并且在更海量的数据应用过程中,存在效率问题。本文提出了基于网格密度的海量空间点聚合显示算法,较好地解决了分布的问题,并提升了算法效率。 相似文献
107.
利用16个微卫星标记对缢蛏F1家系的遗传多样性和标记-性状相关性进行了研究。结果显示,16个SSR位点共检测到39个等位基因,平均等位基因数(Na)和平均有效等位基因数(Ne)分别为2.44和2.09;多态信息含量(PIC)为0.40;平均观测杂合度(Ho)与期望杂合度(He)分别为0.58和0.63,部分位点基因型分布严重偏离孟德尔定律,暗示其可能与适应性基因相连锁,其中YC-8位点附近可能存在杂合不利存活基因。位点YC-96和YC-123与体重呈显著相关(P0.05),YC-96的BC基因型和YC-123的BB基因型均为体重性状的优势基因型,其对应的壳长、壳宽、壳高和体重4个生长性状表型值都最大,可以作为选育快长性状的候选分子标记;YC-1位点与壳宽呈显著相关(P0.05),其中BB型是壳宽的优势基因型;YC-93位点与壳宽、壳高呈极显著相关(P0.01),其中AB型是壳高的优势基因型,BB和BC型是壳宽的优势基因型。对YC-1、YC-93、YC-96和YC-123进行以体重性状为参照的不同基因型组合比较,找到了最优组合(BB/BB(BC)/BC/BB),与4个位点单独分析对应的最优基因型基本完全一致,符合加性作用模型。筛选出的与生长性状相关的标记可为标记辅助选择育种(MAS)提供参考依据。 相似文献
108.
针对目前松软煤层水平段成孔困难、煤层钻遇率较低以及造斜段钻进过程中需要施工导眼井等问题,采用地质导向与几何导向相结合模式,对井身结构优化、钻进参数优选、防塌钻进、多标志层地质导向钻进、水平段井眼轨迹精细化控制等进行研究。在沁水盆地成庄煤矿进行现场应用,钻完井施工顺利,3口水平井都实现无导眼直接一次着陆入靶,水平煤层段累计进尺1 604.72 m,煤层钻遇率达到100%,最终水平段下入PE筛管总长度1 366 m。完善了煤层气水平井钻完井工艺,为煤层气低成本高效开发钻井施工提供技术借鉴。移动阅读 相似文献
109.
Piero Bellanova Mike Frenken Bruce Richmond Jan Schwarzbauer Seanpaul La Selle Frances Griswold Bruce Jaffe Alan Nelson Klaus Reicherter 《Sedimentology》2020,67(3):1230-1248
Far-field tsunami deposits observed in the Kahana Valley, O‘ahu, Hawai‘i (USA), were investigated for their organic-geochemical content. During short high-energy events, (tsunamis and storms) organic and chemical components are transported with sediment from marine to terrestrial areas. This study investigates the use of anthropogenic based organic geochemical compounds (such as polycyclic aromatic hydrocarbons, pesticides and organochlorides) as a means to identify tsunami deposits. Samples were processed by solid–liquid extraction and analyzed using gas chromatography–mass spectrometry. A total of 21 anthropogenic marker compounds were identified, of which 11 compounds were selected for detailed analysis. Although the tsunami deposits pre-date industrial activity in Hawai‘i by several hundred years, distinct changes were found in the concentrations of anthropogenic marker compounds between sandy tsunami deposits and the surrounding mud/peat layers, which may help in identifying tsunami deposits within cores. As expected, low overall concentrations of anthropogenic markers and pollutants were observed due to the lack of industrial input-sources and little anthropogenic environmental impact at the study site. This geochemical characterization of tsunami deposits shows that anthropogenic markers have significant potential as another high-resolution, multi-proxy method for identifying tsunamis in the sedimentary record. 相似文献
110.