查询词典 fractal

Basing on the future of fractal,this paper introduces the density analysis method and points out the defects of existing feature selection method based on fractal dimension.Then a feature selection method based on fractal and changes of neighborhood space density is proposed.

根据数据集的分形特征，引入了密度分析方法，指出了当前基于分形维数的属性选择方法的不足，提出了一种基于分形和邻接空间密度变化的属性选择方法。

This dissertation involves the study of the growth dynamics of colloidal particles under unequilibrium and irreversibility condition. Firstly, it is of interest to investigate whether the ideal diffusion or reaction-limited aggregation universal behavior can be observed for the initially polydisperse practical system of basic yttrium carbonate as well. The fractal structure of basic yttrium carbonate aggregate cluster was observed using transmission eletron microscopy. The aggregation kinetics of basic yttrium carbonate colloids was studed using dynamic 1ight-scattering techniques. At 1.00mol/l NaCl solution the fast diffusion-limited aggregation behavior was observed with an increase in the aggregate size over time described by a power law. The aggregates are characterized by a fractal dimension D=1.82. The disordered and ramified cluster is consisted of primary colloidal particles and tenuous and more open. These are in good agreement with those observed for other colloidal system such as colloidal gold (1.86), silica (1.85) and polystyrene latex (1.82) in diffusion-limited aggregation from the static and dynamic light scattering by Lin. Therefore ideal diffusion-limited aggregation behavior can be observed in practical polydisperse system as well. Smoluchwski and fractal theories were used to obtain the aggregation rate constant for initially polydisperse system for the first time.

本论文研究胶粒的非平衡不可逆聚集动态学，分为两个部分，第一部分是通过实验研究一个新的初始多分散的碱式碳酸钇胶粒实际体系中，聚集标度性质的普适性，即使用透射电子显微技术观测聚集粒子簇的分形结构，使用动态激光光散射研究碱式碳酸钇胶粒的聚集动力学，胶粒带电而产生静电排斥作用使得碱式碳酸钇胶粒处于稳定状态，当加入电解质NaCl溶液时，碱式碳酸钇胶粒间的Debye-Hückel屏蔽距离缩短，从而降低静电排斥能垒，引起胶粒发生不可逆聚集，加入电解质NaCl的浓度为1.00mol/l时，碱式碳酸钇胶粒进行快速聚集，经历扩散控制聚集机理，形成结构疏松、更为开放的分形聚集粒子簇，其分形维数为1.82，碱式碳酸钇胶粒聚集增长动力学遵循幂函数增长规律，与Lin等使用静态激光光散射和动态激光光散射测量硅胶(1.85)、金胶(1.86)和聚苯乙烯胶乳(1.82)在扩散控制聚集状态形成聚集粒子簇的分形维数值以及粒子簇聚集增长的动力学规律相一致，表明胶粒聚集标度性质的普适性质在初始多分散的实际体系中也是存在的，首次由动态激光光散射的实验数据得到初始多分散胶粒分形粒子簇的聚集速率常数，并且其值与Smoluchowski聚集速率理论预期相符。

The block-based fractal image compression method has a low compression ratio, so simple region-based fractal image compression is introduced, then the competitive region-based fractal image compression method is presented. The experimental results show that the compression ratio is effectively improved at a similar PSNR value.

由于基于块的分形图像压缩方法的压缩比不高，对此进行改进，先介绍简单的基于区域的分形图像压缩，然后提出基于区域的竞争分形图像压缩算法，并进行实验，实验结果表明，该方法在保持一定的信噪比的情况下，有效的提高了压缩比。

That a root system growth is more complete when fractal dimension value is higher, and when a growth of root system is simple and slow, then its fractal dimension value is smaller, and the same fractal dimension or the dimension is near, the form construction of root system becomes to similar.

当碎形维度值愈高，根系生长愈复杂，当碎形维度值愈低其根系的生长型态较简单且生长较慢，而且当两者之碎形维度很接近时其生长的型态也非常相似。

Using the same method, we can know that the fractal character exists for Lianyungang's coastline and Yancheng's, Nantong's, the fractal value of each is 1.0531, 1.0693, 1.1495. The values of fractal show that the extension of sinuation of coastline change complex, and so the distributing space is larger gradually from north to south.

采用相同的方法和标度，江苏省沿海三个地级市连云港、盐城、南通的海岸线在1：50000地形图上同样具有分形的特征，分维值分别是1.0531、1.0693、1.1495，由北向南逐渐增大，反映了江苏省海岸线的弯曲程度由北向南逐渐变复杂的趋势，相应的海岸线在平面上展布的空间由北向南也是愈来越大。

The three dimension reticular cell counting method is adopted to calculate the fractal dimension characterizing skew degree of gray level surface. With the two-dimension reticular cell counting method, the fractal dimension characterizing wrinkle shadow block distribution is obtained. By means of distribution function, the fractal dimension for the size distribution of wrinkle shadow block can be achieved.

提出以尺度变化的立体网格计算灰度曲面的分维数，表示灰度曲面的起伏程度；以尺度变化的平面网格计算织物折皱阴影块分布的分维数，表示阴影块的离散程度；以当量直径为尺度，计算分布函数的分维数，表示织物折皱阴影块尺寸的分布。

This paper creatively introduce fractal theory into the study of municipal networks(include pipe networks, sewer networks and storm sewer networks), analyze their fractal character and explain their physical mechanism, which is the origin of the fractal structure.

本文以市政管网（包括供水、污水和雨水管网）作为研究对象，创造性的引入分形理论，分析论证了管网的分形特性及其形成的物理机制。

Fractal dimensions of images have been calculted using usual methods such as triangular prism method, fractal Brownian motion method, DBC box-counting method and multi-fractal method.

实现了常用的三角棱柱法、分形布朗运动法、DBC计盒法和多重分形法等分维数计算。

This paper researched the Fractal theory and suggested that it can be applied in Packing CAD System. The parameter design of fractal image was realized to stimulate anomalous scenes and draw typical fractal pictures.The paper aimed to upholster packing products,to publicize packing merchandises and to defend fake brands.

本文通过对分形理论的研究，提出将分形理论应用到包装CAD系统，并实现参数化设计，在计算机上模拟不规则的自然景物和典型的分形图案，目的是借助分形图案的自相似和无限延展的特性，帮助我们进行包装产品的装潢设计、包装商品的宣传及包装商标的防伪。

Two novel fractal network microchannel heat sinks are originated, namely, the biomimetic fractal tree-like microchannel net born of mammiferous aspiratory system and the biomimetic fractal comby microchannel net born of natural honeycomb.

首次提出并加工出了树状分形结构微管道网络换热器和仿蜂巢结构微管道网络换热器；分别对2种硅制分形结构微管道网络换热器的流动与换热特性进行分析，并与平行阵列型微管道换热器进行了对比。

Liapunov—Schmidt method is one of the most important method in the bifurcation theory.

Liapunov—Schmidt方法是分叉理论的最重要方法之一。

Be courteous -- even when people are most discourteous to you .

要有礼貌──即使当別人对你最不礼貌的时候。