共查询到18条相似文献，搜索用时 109 毫秒
1.
新疆西滩金矿床金品位分维D值及其意义 总被引：4，自引：0，他引：4
利用分形理论研究了新疆西滩金矿金品位分布的分维结构特征,并对分维Ｄ 值的地质意义进行了讨论。研究表明,较小的分维值及具有多标度分形,是形成富矿的有利条件。 相似文献
2.
在剔除粗差的基础上,以GPS连续站低频拟合残差时间序列在站心坐标系下的空间分布作为研究对象,运用分形理论中测度关系求分维方法求得全国27个连续站残差空间分布的分维及其无标度区间,并讨论了落入无标度区间的点占总点数的百分比情况|同时,利用相关系数及F检验方法对无标度区间内是否符合线性特征进行显著性检验。主要结果如下：1）除DXIN、QION和XIAA三个连续站残差序列无标度区内线性相关系数在0.99～0.995之间外,其他24个台站无标度区间内的线性相关系数都在0.995以上|27个连续站无标度区内线性回归F检验在α=0.005时全部拒绝不符合线性分布的零假设(H0:b=0),表明GPS残差序列在无标度区内符合分形特征,即具有较高的自相似性特征。2）除BJFS、LUZH和XIAM三个连续站无标度区间内的点数占各自总点数的40%左右外,其余24个台站无标度区间内的点数占各自总点数的50%甚至60%,说明残差序列中符合分形规律的点约占自身总点数的一半或以上,表明自然分形规律在残差序列中占有一定的权重。3）27个连续站在无标度区间内的分维值在1.71～1.97之间,即各台站分维值为非整数值且存在着差异性|另外,在构建涉及指数的GPS观测模型或噪声模型时,如果选取其分维值作为各自的模型指数,则有可能减少模型的系统误差。 相似文献
3.
《地球科学与环境学报》2018,(6)
通过对2013年南海西部综合航次于南海琼东陆架海域采集的3根沉积柱(C1、C2、C4)样品进行粒度分析,对粒度的分形特征及其影响因素进行探讨。使用矩法计算出沿离岸方向3根沉积柱样的平均粒径分别为5.33Φ、6.14Φ、6.26Φ,粒度总体上较细;标准偏差平均值分别为2.59Φ、2.19Φ、1.82Φ,表示分选性逐渐变好;偏度平均值分别为0.40、-0.02、0.48,其变化规律不明显;峰度平均值分别为1.75、2.27、2.70,其值逐渐增大。利用幂指数法,在累积体积百分比5%～95%范围的无标度区间内计算得到沉积物样品的粒度分维值,总体范围为2.24～2.54,平均值分别为2.52、2.45和2.30,处于较高水平;随着离岸距离的增加,样品粒度分维值逐渐降低,但分选性变好;粒度分维值与标准偏差存在显著正相关关系,说明分选性对粒度的分形特征产生影响。根据C-M图,沉积柱样的流体为牵引流,颗粒的主体搬运方式由沉积柱C1的滚动逐渐转变为沉积柱C4的悬移;对比发现,以滚动组分为主的颗粒粒度分维值较大,以悬移组分为主的颗粒粒度分维值较小,说明分形程度受搬运方式和水动力条件的影响。 相似文献
4.
地壳中元素和矿化分布的不均匀性是一个普遍规律。从超大型矿床→大型矿床→小型矿床→矿点、矿化点（或高异常点）的分布，是近似于从有限稀硫分布逼近无穷多且无限稀硫分布。因此可以把矿床的分布看成是随机康托集（Cantordust）在空间上的分布。浙江中生代热液萤石、银、铅锌矿床的分形丛集分布存在于两个尺度范围内，分形丛集的分维数为0．196～0．40（1～20km）和1．161～1．219（20～750km）。矿床的频度—大小分布也是分形的，其储量分形分布的分维数为：萤石（中国）D=2．13；萤石（浙江）D=2．34；银（浙江）D=1．63；铅锌（浙江）D=2．27；钨（中国）D=2．16；铜（世界）D=2．55。我们认为，矿床储量的分形分布，对于各种标度的成矿作用可能是一个普遍性的特征。根据矿床的频度—大小分形关系，有可能对一地区大于某一指定储量的潜在矿床数作出预测。 相似文献
5.
胶东乳山蓝家庄金矿床为近年来胶东东部牟平-乳山金成矿带探明的一处大型金矿床。该文通过系统收集该矿床Ⅰ号矿体金品位数据,综合运用特征参数统计和分形理论,分析了金品位特征参数垂向变化规律及垂向分形结构特征。研究结果表明,金品位具有显著的多重分形结构特征,矿化较好地段一般具有3～4个分维值,而矿化较差地段一般仅具有1个分维值。金品位特征参数和分形结构的规律性变化指示蓝家庄金矿床Ⅰ号矿体向-500m标高以深仍有一定程度地延伸,预测深部具有良好的找矿前景。 相似文献
6.
本文汇总整理了2000-2014年中国发生的472起重特大煤矿事故,获得其空间分布状况;基于分形理论,利用网格法统计不同网格尺度下覆盖重特大煤矿事故的非空网格中的事故数量,计算煤矿事故的全国、三大自然地理区以及干湿分区的分维值,分析其空间分布分形特征;利用R/S方法研究15年来重特大煤矿事故发生的时间分形特征。研究表明,从全国范围来看,重特大煤矿事故具有较好的空间分形特性,但不同区域的重特大煤矿事故的分形特性却具有很大差别。15年来发生重特大事故数量及事故死亡人数逐年下降,由R/S分析得到的Hurst指数表明事故时间序列的分形特征客观存在,并且年发生事故数量及事故死亡人数量减少趋势。 相似文献
7.
分形方法是测度城市生长与形态演化的重要方法,然而其标度区范围的自然识别依然存在瓶颈。本文采用二阶导数识别半径法标度区界线,结合经典计盒法模型提出改进的双维分形标度律测算方法,以郑州市为案例区验证模型的精度与效度,综合解析郑州城市空间形态结构的生长演变特征。结果显示:① 利用二阶导数自动识别半径法标度区界线可显著提升分形模型拟合效果,拟合精度R2由0.920提升至0.996以上;② 郑州城市空间结构存有双标度现象,城市生长扩张并非标准环形波状推进,半径法模型仅在“城市中心边缘—建成区内侧”的环状范围拟合有效,城市结构可能存有自仿射生长或随机多分形特征;③ 1982—2020年郑州城市形态演化为明显的中心蔓延模式,职能用地的空间配置整体均匀程度偏高,功能分异程度较低,存有城市景观较紊乱,系统效率不高的隐患。本研究对半径法分形模型中拟合精度难以提升的应用瓶颈作出了突破性尝试,为城市生长模拟与城市空间结构演变分析提供了一种新方法,丰富了城市分形研究。 相似文献
8.
以分数维为分析指标的分形几何理论,为地图点群目标的空间复杂性分析提供了一种定量方法。但是研究表明,地图点群目标的分形性质往往表现出局部的非均匀特性,因此主要以研究对象整体分维估值为主的分维分析方法难以描述这种变化。本文在分维扩展方法的基础上,提出了一种基于滑动窗口的局部分维分析方法--元分维模型,并通过实践证明该方法可以有效地揭示地图点群空间分布特征的差异,从而为地图点群目标的空间分布特征分析提供了一个新的思路。 相似文献
9.
本文采用关联维的计算方法,对四川西部道孚6.9级地震和青海共和6.9级地震过程中的垂直地形变序列分维数进行了计算,得到了如下初步结论和认识:(1)上述两震区远场地形变序列分维数为0.63～0.73,而近场(震中区)序列分维数为0.12～0.49,近场出现明显的降维现象;(2)孕震期间地形变观测序列分维数为0.32～0.46,而震后时期则为0.72～0.85,孕震过程中地形变序列存在明显的降维现象。 相似文献
10.
采集寺庄金矿区82个钻孔的金品位数据4597个,按照100m的标度分析其在垂向上的均值、标准差、变异系数和大于工业品位的矿石所占比例等统计参数,对比其在垂向上的分形分维值特征,发现如下规律：寺庄金矿区深部矿体明显优于浅部矿体,以-700- -800m区间为矿化中心,垂直分布至少500m以上;通过围岩蚀变分带特征、矿石组合特征、井下脉体相互穿插关系和金品位分形分维值研究,说明该区金成矿时间上至少经历了3次地质成矿作用的叠加,其中显著成矿作用发生在后2次,在空间上深部（-1000m以下）具有较大的找矿潜力;金 相似文献
11.
ZHUXiao-hua CAIYun-long 《中国地理科学(英文版)》2004,14(1):9-14
MANDELBROT enunciated the uncertainty of the length of a coastline in his paper “How long is the coastline of Britain?” published in Science in 1967. The fractal concept was presented for the first time in that paper and has been applied to many fields ever since. Although fractal dimensions of lots of phenomena were calculated by the box-counting method, the quantitative influence of series of square grids on them is ignored. The issue is systematically discussed as a case study of the mountains of China‘s Mainland in this paper. And some significant conclusions are drawn as follows: 1) Although the fractal character objectively exists in the mountains of China‘s Mainland, and it does not vary with the changes of series of square grids, the fractal dimensions of the mountains of China‘s Mainland are different with these changes. 2) The fractal dimensions of the mountains of China‘s Mainlandvary with the average lengths of sides of series of square grids. The fractal dimension of the mountains of China‘s Mainland is the function of the average length of side of square grid. They conform to the formula D=f(r) (where D is the fractal dimension, and r is the average length of side of square grid). 3) Different dots of data collection can affect the fractal dimension of the mountains of China‘s Mainland. 4) The same range of length of side of square grid and dots of data collection can ensure the comparison of fractal dimensions of the mountains of China‘ s Mainland. The research is helpful to get the more understanding of fractal and fractal dimension, and ensure that the fractal studies would be scientific. 相似文献
12.
ZHUXiao－hua WANGJian 《中国地理科学(英文版)》2002,12(2):142-145
MANDELBROT enunciated the uncertainty of the length of a coastline in his paper“How long is the coast-line of Britain?“ published in “Science“in 1967.The fractal concept was presented for the first time in that paper and has been applied to many fields ever since.According to the fractal theory and conditions of fractal research of coastline,the controls of faults and biologic function on the fractal character of coastline are preliminarily discussed on the basis of GIS in this paper.Finally,some significant conclusions are drawn:1)the faults control the basic trends of coastlines of two study areas;2)the fractal dimension of coastline of Taiwan is smaller than that of Changle-Lufent,because the faults of Taiwan more intensely control the trend and fractal dimension of the coastline;3)the larger the fractal dimension of the faults or the major faults ,the more the controlling effect of them on the trend and fractal dimension of coastline;4)the larger fractal dimension of the coastline of Changle-Lufeng indicates that the biologic function intensely shapes the coastline .In a word ,the controls of faults and biologic function on the fractal character of coastline are discussed with a case study of China in this paper,it can be seen that faults and biologic function both have influence over the trend and fractal dimension of coastline,the fractal mechanism of coastline of two study areas may be so. 相似文献
13.
Patel NILANCHAL 《中国地理科学(英文版)》2006,(1)
1INTRODUCTIONMandelbrot stated the uncertainty of the length of a coastline in his paper "How long is the coast of Britain? Statistical self-similarity and fractional dimension" pub- lished in Science in 1967 (MANDELBROT, 1967). The concepts of fractal and fractal dimension were presented for the first time in that paper and have been applied to quantitatively describing the difference of crooked coastlines of British and South Africa. Compared with the Euclidean geometry with more… 相似文献
14.
朱晓华 《中国海洋湖沼学报》2004,22(2):130-135
Fractal theory was applied to a preliminary discussion of the fractal character and formation mechanism of the coastline of the bedrock coast of China on the basis of GIS ( Geographical Information System). Some significant conclusions were drawn : ( 1 ) The fractal dimensions of the coastline and linear structures of Liaodong Peninsula are 1.0093 and 1.0246 respectively, those of Shandong Peninsula are 1.019 and 1.021 respectively, etc. (2) The fractal dimensions of coastlines of Liaodong Peninsula, Shandong Peninsula, Zhejiang and Fujian-Guangdong tend to increase with the spatial change from north to south. (3)The regional linear structures( including faults)control the basic trends and fractal dimensions of coastlines as a whole in the regions of the bedrock coast of China : the more the controlling effect of linear structures, the smaller the fractal dimensions of coastlines. (4)The substantial constituents of coast and biologic function both play an important role in affecting the fractal dimensions of coastlines of Liaodong Peninsula,Shandong Peninsula, Zhejiang, Fujian-Guangdong and Taiwan Island. 相似文献
15.
Symmetrical relationships between humans and their environment have been referred to as an extension of symmetries in the human geographical system and have drawn great attention. This paper explored the symmetry between physical and human systems through fractal analysis of the road and drainage networks in Wuling mountainous area. We found that both the road and drainage networks reflect weak clustering distributions. The evolution of the road network shared a significant self-organizing composition, while the drainage network showed obvious double fraetal characteristics. The geometric fractal dimension of the road network was larger than that of the drainage network. In addition, when assigned a weight relating to hierarchy or length, neither the road network nor drainage network showed a fractal property. These findings indicated that the fractal evolution of the road network shared certain similarities with fractal distribution of the drainage network. The symmetry between the two systems resulted from an interactive process of destroying symmetry at the lower order and reconstructing symmetry at the higher order. The relationships between the fractal dimensions of the rural-urban road network, the drainage network andthe urban system indicated that the development of this area was to achieve the symmetrical isomorphism of physical-human geographical systems. 相似文献
16.
遥感与GIS的青海湖岸线分维研究 总被引：2，自引：0，他引：2
讨论了TM图像以及分形几何学对青海湖岸线问题的求解算法,同时估算了不同像元尺度下,青海湖的岸线长度得出青海湖岸线的分形维数为1.0237,并探讨了其地学意义,研究表明,分形维数不仅是一种可行的表达岸线特征的方法,而且岸线分维数的计算可大大减少工作量和提高工作效率,可见遥感与GIS技术在岸线分维数的计算中,具有十分良好的应用前景。 相似文献
17.
范长新 《大地测量与地球动力学》2019,39(5):476-481
介绍TPXO、FES、Chinatide、MIKE Global Tide、Utide等典型海潮模型,总结归纳其同化潮汐数据来源和最新的海洋地形数据,利用我国沿岸长期验潮站以外的26个中短期潮位观测站评估TPXO等海潮模型预报精度。结果表明,全球海潮模型对我国沿海M2分潮的预报精度普遍较低,且主导了几种海潮模型在中国海域的整体预报精度;相比MIKE Global Tide和TPXO7.2,TPXO8、TPXO_Yellow Sea 2010和TPXO_China&Ind模型在我国沿海的预报精度更高。 相似文献
18.
ZHU Xiao-hua Patel NILANCHAL ZUO Wei YANG Xiu-chun 《中国地理科学(英文版)》2006,16(1):48-55
Based on the fractal theory, the spatial structure of China＇s vegetation has been analyzed quantitatively in this paper. Some conclusions are drawn as the following. 1） The relationships between size and frequency of patch area and patch shape index exist objectively for China＇s vegetation. 2） The relationships between perimeter and area exist objectively for China＇s vegetation. 3） The fractal dimension of evergreen needleleaf forests on mountains in subtropical and tropical zones is the largest, while the smallest for deciduous broadleafand evergreen needleleaf mixed forests in temperate zone, reflecting the most complex spatial structure for evergreen needleleaf forests on mountains in subtropical and tropical zones and the simplest for deciduous broadleaf and evergreen needleleaf mixed forests in temperate zone. 4） The fractal dimensions of China＇s vegetation types tend to decrease from thc subtropics to both sides. 5） The stability of spatial structure of deciduous broadleaf and evergreen needleleaf mixed forests in temperate zone is the largest, while the smallest for double-cropping rice, or double-cropping rice and temperate-like grain, and tropical evergreen economic tree plantations and orchards, reflecting the steadiest for deciduous broadleaf and evergreen needleleaf mixed forests in temperate zone and the most unstable for double-cropping rice, or double-cropping rice and temperate-like grain, and tropical evergreen economic tree plantations and orchards in spatial structure. 6） The stability of spatial structure of China＇s vegetation tends to decrease from the temperate zone to both sides, it is significantly pertinent to understand the formation, evolution, dynamics and complexity rule of ecosystem of vegetation. 相似文献