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161.
表面起伏形态的特征决定了岩体结构面粗糙度系数的基本性质,研究结构面起伏幅度的变化规律,有助于分析粗糙度系数的尺寸效应。试验利用自行研制的大、中、小岩石结构面轮廓曲线系列仪器,测量不同尺寸结构面表面形态的起伏幅度。通过统计和分析结构面起伏幅度随取样长度的变化规律,结果表明:起伏幅度存在尺寸效应,同一结构面测量方向相同但测量位置不同的起伏幅度是有差异的,但变化趋势相同。中等尺度及大尺度结构面的起伏幅度均呈现出随结构面尺寸的增大而增大的变化规律,当结构面尺寸增大至一定值时,起伏幅度会趋向于不同的定值。不同结构面起伏幅度统计均值与结构面尺寸的变化曲线,均呈现出较好的对数函数关系。 相似文献
162.
地震分析预报的重力变化异常指标分析 总被引：3，自引：2，他引：1
定义了描述地震前重力变化异常时变距和量级的参数S和G。根据收集到的89个4.0级以上地震震例,统计分析了震前重力变化异常范围和量级与震级的关系,得到了流动重力地震分析预报的量化参考指标。结果表明:5、6、7、8级地震震级判定的重力变化异常量级参考指标分别为50、70、90、120μGal,重力变化异常范围参考指标分别为140、220、350、660km。此外,由于流动重力观测周期等方面的局限性,根据流动重力观测资料尚难以获得震级与重力变化异常时间过程的关系。 相似文献
163.
Soil wind erosion processes include mechanical process and dynamic changes of the factors affecting soil wind erosion, as well as the corresponding changes of wind erosion rate. The former is rich in experimental and theoretical researches that have clearly defined the process of particle starting, transporting and settling. The latter focuses on the dynamic changes of various wind erosion factors and the response of soil wind erosion rate to the change of the factors, of which systematic research of which is very limited. The difficulties in research of soil wind erosion process include: ①Dynamic parameterization of wind erosion factors; ②Observation and quantitative expression of the dynamic changes of wind erosion factors; ③Scaling problem of wind erosion process; ④Prediction ability of wind erosion models. At present, it is urgent to carry out the following work on soil wind erosion. The first is to establish standard wind erosion observation field in typical regions to obtain continuous and complete data of wind erosion in the field; the second is to study the saturation path of wind sand flow to solve scale problem; and the third is to construct a wind erosion model with solid theoretical foundation and fully consider both mechanical process of soil wind erosion and dynamic changes of the factors. 相似文献
164.
《地学前缘(英文版)》2018,9(6):1609-1618
Rock properties exhibit spatial variabilities due to complex geological processes such as sedimentation,metamorphism, weathering, and tectogenesis. Although recognized as an important factor controlling the safety of geotechnical structures in rock engineering, the spatial variability of rock properties is rarely quantified. Hence, this study characterizes the autocorrelation structures and scales of fluctuation of two important parameters of intact rocks, i.e. uniaxial compressive strength(UCS) and elastic modulus(EM).UCS and EM data for sedimentary and igneous rocks are collected. The autocorrelation structures are selected using a Bayesian model class selection approach and the scales of fluctuation for these two parameters are estimated using a Bayesian updating method. The results show that the autocorrelation structures for UCS and EM could be best described by a single exponential autocorrelation function. The scales of fluctuation for UCS and EM respectively range from 0.3 m to 8.0 m and from 0.3 m to 8.4 m.These results serve as guidelines for selecting proper autocorrelation functions and autocorrelation distances for rock properties in reliability analyses and could also be used as prior information for quantifying the spatial variability of rock properties in a Bayesian framework. 相似文献
165.
地震信号中的随机噪声是一种干扰波,严重降低了地震信号的信噪比,并影响着资料的后续处理和分析.本文根据地震信号中有效信号和随机噪声的差异,结合分数阶B样条小波变换与高斯尺度混合模型提出了一种地震信号随机噪声压制方法.首先利用分数阶B样条小波变换将含噪地震信号映射到最优分数阶小波时频域内,然后对各小波子带系数分别建立高斯尺度混合模型,由贝叶斯方法估计出源地震信号小波系数,最后使用分数阶B样条小波逆变换重构得到降噪后的地震信号.利用本文方法对合成地震记录和实际地震信号进行降噪处理,实验结果表明本文方法能够有效地压制地震信号中的随机噪声,并且较好地保留了有效信号.
相似文献166.
随着舟山群岛海洋文化产业的不断开发和旅游产业的体系日益成熟,两大产业呈现出相互渗透相互融合的态势,带来了舟山海洋文化产业发展的新契机。文章阐释了产业融合的内涵和对舟山海洋文化产业发展的推动意义,剖析了舟山海洋文化产业发展的历史、现状以及所面临的缺乏文化资源转化为产能、传统文化表现手法陈旧、缺少大规模市场等问题,提出了旅游产业与海洋文化产业的融合路径和舟山海洋文化产业发展需要改造传统文化产业,创新文化产品;运用现代科技,促进海洋非物质文化旅游发展;加快发展文化内容产业,促进产业结构调整;充分运用政府引导作用,推进海洋文化产业与旅游产业深入融合;培育大型企业,扶持中小型企业,形成文化产业规模效应;加大教育投入,培养高素质人才等相关性策略。 相似文献
167.
With the intensification of urbanization and global warming, the problems of urban thermal environment are increasingly prominent. On the basis of the remote sensing, geographic information system, geostatistics and multiscale spatial pattern, the spatial-temporal variation characteristics of land surface temperature in urban thermal environment were quantitatively analyzed. The results are as follows:
168.
169.
Emily C. Hazell Claus Rinner 《International journal of geographical information science》2020,34(8):1648-1681
ABSTRACT Modelling changes in biodiversity have become a necessary component of smart urban planning practices. However, concepts such as biodiversity are often evaluated using area-based composite indices, the results of which are heavily reliant on specific parameters chosen. This paper explores the design and implementation of a butterfly biodiversity index by comparing two widely accepted modelling techniques: principal component analysis and spatial multi-criteria decision analysis (MCDA). A high degree of scale dependency has been demonstrated in previous studies exploring the use of area-based composite measures. To evaluate the impact of scale, each model was assessed at two different spatial resolutions. The outcomes were analyzed, mapped and compared using ordinary least squares, geographically weighted regression and global Moran’s I to evaluate relative biodiversity patterns across the City of Toronto, Canada. Findings indicate that the impact of spatial scale was significant, whereby the coarser resolution models were found to be more highly correlated with biodiversity, compared to the finer resolution models. The results of this study contribute to a growing body of literature that explores key conceptual questions regarding the robustness of GIS-based MCDA, the impact of scale in urban ecology studies, and the use of composite indices to manage spatial ecological data. 相似文献
170.
鉴于传统各向异性二维半变异函数各向同性化方法未充分考虑或无力精确描述其内部结构信息的缺陷,本研究通过引入线性广义尺度不变(GSI)模型,以DEM数据作为验证对象,对二维半变异函数各向异性结构信息进行多尺度建模,并采用旋转椭圆法、两步搜索作图法等方法对系统参数进行估计,最后以球状模型为例对理论半变异函数的估计精度,及其在... 相似文献