利用SEM照片获取土的孔隙结构参数

以土工实验和计算机图像处理技术为基础, 探讨利用SEM照片获取土的孔隙结构参数的方法, 并以重塑粘性土为例进行实证分析.为获取孔隙结构参数, 首先分3个步骤对土样的SEM照片进行图像处理: 即照片格式转换、颗粒边际线探测和颜色充填; 然后针对黑白二元图像测算孔隙结构参数.从设计制备的重塑粘性土的三轴试验样品中, 选择了12个不同水分状态和密度状态的样品, 经风干和烘干后, 进行SEM测试, 每个样品拍摄了3个尺度的SEM照片, 放大倍数依次为500倍、1000倍、2000倍.之后, 对所获得的SEM照片进行了图像处理分析, 计算了相应的平面孔隙比和平面孔隙率.数据分析表明: SEM照片测算的孔隙参数与通常三相图计算的孔隙参数有关联, 测算数据可以反映土的孔隙结构特征; 样品的不同脱水方式对SEM照片测算的孔隙参数有影响, 与三相图法计算数据相比, 风干土样测算的数据略有偏大, 烘干土样测算的数据偏小; 同一土样不同比例尺的SEM照片测算出的孔隙参数有所不同, 邻近三相图法计算结果上下波动; 利用SEM照片提取土的结构信息是可行的, 对SEM照片进行图像处理分析是获取土的孔隙结构参数的有效办法.      

武汉市汤逊湖沉积物重金属垂向变化的磁响应特征及环境意义

对武汉汤逊湖湖泊沉积物T06-1样芯进行了磁性测量、重金属分析和粒度分析,探讨了利用磁参数追踪、指示城市湖泊重金属污染的可行性.结果表明,低矫顽力的亚铁磁矿物主导了沉积物的磁性特征.磁参数χ,SIRM和ARM与重金属Cr,Zn,Cu和Pb呈现较为一致的垂向变化特征:55cm之下,磁参数值和重金属的含量均较低且稳定;在50～10 cm之间,两者基本呈现随深度的减小而增加的趋势,其中在20～10 cm区间,出现小范围内波动;而10cm至表层,元素含量和磁参数值随深度减小而急剧增加.选取粘土(＜4μm)对沉积物中Cr,Zn,Cu和Pb进行粒度校正的结果显示:校正后元素的变化趋向于平稳,但在表层的10cm处Cr,Pb,Zn和Cu的含量仍然较高,表明了表层沉积物中金属元素的含量主要受人类活动的影响.相关分析也表明了磁参数χ,SIRM和ARM与重金属Cr,Pb,Zn和Cu之间均呈显著相关关系(0.62≤R≤0.86),表明磁参数可以用于追踪和指示汤逊湖湖泊沉积物重金属污染.     

ICESat-2植被冠层高度和地表高程数据产品用于森林高度提取的效果评价

由美国宇航局(NASA)研制的新一代冰、云和陆地高程卫星(ICESat-2)于2018-09-15发射成功,其搭载的先进地形激光测高系统(ATLAS)采用微脉冲多波束光子计数激光雷达技术,可用于全球高程线采样数据的获取.目前公开发布了9种数据产品,其中包括植被冠层高度和地表高程数据产品(ATL08),为全球森林结构参数...     

Characteristics of Radar Echo Parameters and Microphysical Structure Simulation of a Short-Time Heavy Precipitation Supercell

By using the conventional observations, radar data, NCEP/NCAR FNL 1°×1° reanalysis data and numerical simulation data and with the construction and calculation of radar echo parameters, this paper presents the structural characteristics and physical processes of a short-time heavy precipitation supercell that occurred in the squall line process in Shanxi Province on 24 June 2020. The results show that this squall line event occurred in front of a surface cold front,combined with infiltration of ...     

环境温度对板式橡胶支座摩擦滑移性能的影响分析

采用有限元模拟的方式,对板式橡胶支座摩擦滑移特性进行分析,并与常温试验中获得的支座摩擦滑移滞回曲线、等效黏滞阻尼比等进行了对比.在获得可靠模型的基础上,分析环境温度对板式橡胶支座摩擦滑移特性的影响,研究了温度与支座摩擦滑移耗能、等效黏滞阻尼比和滑动起始距离的关系.结果表明:(1)板式橡胶支座的有限元模型可以较好地实现支...     

Falling sphere observations of anisotropic gravity wave motions in the upper stratosphere over Australia

A study of inertial scale gravity wave motions in the region of the atmosphere between 30 and 60 km has been undertaken, using wind and temperature data derived from rocket-borne falling sphere density experiments performed over Woomera, Australia between 1962 nad 1976. The gross features of the wave field compare favorably with those found in similar northern hemispheric studies. Wave propagation is found to be both vertically and horizontally anisotropic. A rotary spectral analysis indicates predominately upgoing wave energy, suggesting that the majority of sources of these waves lie below 30 km. A detailed statistical investigation of the waves, made using the Stokes parameters technique, reveals that phase progression is also highly directional in the horizontal, with a significant zonal component in summer, but with a strong meridional component in winter. Propagation towards the southeast is inferred in summer, with the waves possibly emanating from tropospheric sources in equatorial regions to the north of Australia. The technique also shows that, on average, the waves appear to have mean ellipse eccentricities (=f/) around 0.4–0.45. Indirect estimates of a number of important wave parameters are made. In particular,v andw flux estimates are made over several height intervals. The vertical gradient of density weighted flux implies wave-induced mean flow accelerations of the order 0.1–1 ms^–1day^–1. This suggests that dissipating gravity waves are a significant source of the momentum residuals that are encountered in studies of satellite data from this region.     

Relocation of Hypocenters in the Bohai Sea and Adjacent Areas

In this paper a method of relocating hypocenter in inhomogeneous medium is introduced.Based on the velocity from the latest results on the crust and mantle structure of the Bohai Sea and its adjacent areas,by using the data recorded in Shandong,Hebei,Beijing,and Liaoning networks around the Bohai Sea we apply the method to relocate hypocenter parameters of 598 events occurring in the Bohai Sea and its adjacent areas.The accuracy of hypocenter relocation is discussed.We present the results of events ML≥4.0 in the Bohai Sea in recent years and discussed the distribution of focal depths.     

Anisotropy of magnetic susceptibility parameters: Guidelines for their rational selection

Twenty-eight parameters used to characterize measurements of the anisotropy of magnetic susceptibility are compared theoretically in this work by introducing the concept of the field of susceptibility tensors, which allows the representation of parameters as families of lines in a plane. It is demonstrated that the foliation and lineation parameters are but a special case of the shape parameters, implying that the resolution of these two rock fabric elements using AMS measurements alone is more an artifact of the numerical range of definition of some parameters than a quantification of two physically independent features. Also, it is shown that parameters presumably of the same type do not necessarily yield equivalent interpretation of results in a qualitative sense, and therefore, caution should be strongly exercised when parameters are to be selected. Paramters quantifying the degree of anisotropy are, in general, equivalent to each other because of the very small departure observed in natural rocks from the isotropic case. However, a final consideration of the possible ability to differentiate rock types and a convenient range of values allowing expression of the degree of anisotropy in a well-defined percentage are pointed out as the main factors to be considered before selecting one parameter within this class.     

矿物热敏参数测试仪及其在地质找矿中的应用

介绍了国内外第一台矿物热敏参数测试仪研制的原理、应用范围和对一些金属矿物、半导体矿物的测试情况以及仪器在浙江、赣南等地区金矿找矿中的初步应用。     

辽宁及其邻区1900—1949年M≥5级地震参数研究

我们搜集了国际国内地震台网资料、宏观考察资料、地震专题研究报告,对1900—1949年5级以上地震全部进行了核查,重新进行定位处理,并结合宏观考察资料和前人工作成果进行分析研究,得到较为准确的震中位置。通过这项研究,增补了原目录中遗漏的地震,并对目录中的错误进行了修正,从而得到一份较为完整可靠的地震目录。