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提出了用分形理论来建立微粒布朗运动特征模型的设想,并从理论上阐明了它的有效性。在此基础上进行分析,得到了模型的分形特征和微粒尺寸参数间的关系。结合图象信号处理技术,可从计算的分形维值中获取粒度信息,进而可得到一种超继微粒粒度测试的方法。 相似文献
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详细介绍了在显微TV计算机系统中获取颗粒布朗运动轨迹的跟踪处理算法,并在此基础上提出了一种测量超细颗粒布朗运动轨迹获取粉体材料的粒径及其分布信息的方法。 相似文献
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为了刻画标的资产呈现出的“波动率微笑”和“长相依”等特性,基于分形市场理论用标准布朗运动和分数布朗运动■的线性组合代替布朗运动,构建了混合分形Heston-CIR模型来描述标的资产价格。其次,讨论了该模型下随机微分方程的解的存在唯一性,并研究了利率方程的Euler格式离散化的强收敛性。最后,用最小二乘Monte Carlo算法对美式看跌期权进行数值模拟验证模型的有效性。 相似文献
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超细粉体粒度测量技术现状和新方法的探索 总被引:6,自引:0,他引:6
概述了粉体材料在国民经济、国防现代化、现代高科技领域应用中所具有的重要意义,总结了粉体测量技术的国内外现状及其存在的问题,提出了依据朗之万布朗运动模型理论测量超细颗粒布朗运动轨迹获取粒径信息的一种新方法。 相似文献
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《西安石油大学学报(自然科学版)》2014,(5)
基于粗集料粉体颗粒的Fuller堆积模型及分形理论,评价了4种硅酸盐水泥调剖剂实测和模型计算的粒度分布分形维及其与封堵性能的关系。结果表明,测试粒度分布与Fuller法计算结果均有偏差,粗颗粒比细颗粒的含量高。测试的4种样品粒度分布分形维2.079 4~2.233 3,小于Fuller法计算结果拟合得到的分形维数2.6。4种样品空隙率62.46%~65.01%,固化抗压强度22.1~25.5 MPa,硅酸盐水泥调剖剂颗粒粒度分布分形维数越大,其空隙率越小,颗粒堆积结构越紧密,固化后的抗压强度越高,调剖的封堵能力和抗后续注入水冲刷能力越强。调剖工程设计中,可将测算的粒度分布及分形维数作为硅酸盐水泥调剖剂种类选择、封堵性能评价的参考依据。 相似文献
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多径衰落信号的多重分形谱 总被引:5,自引:0,他引:5
利用多重分形模型对多径衰落信号的分形特征进行了分析和讨论。通过分析,指出多径信号的多重分形谱特征是描述移动通信信道的重要参数,并引入了一种利用相空间重构的思想来提取信号多重分形特征的算法。结合分数布朗运动模型,对多径信号的重构进行了研究,对实测数据的分析结果表明,分形模型与传统的统计模型相比能更精确地描述多径衰落信号。 相似文献
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分形图形是计算机图形中的一个重要分支,它通常是通过递归回溯法实现。本文通过剖析Koch分形曲线算法的实现,来推理其它分形图象(矩形分形曲线、Tree分形曲线、雪花分形曲线)的算法。 相似文献
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分形布朗运动模型及其在地形分析中的应用 总被引:17,自引:1,他引:17
研究了分形布朗运动(FBM)模型在DEM数字高程地形地貌分析中的应用.以分形维数FD,数据方差σ^2为特征实现了对地形的分类.同时在分析中引入了分形度以衡量DEM高程数据分形特性的强弱.实验证明了FBM模型在地形分析中的有效性. 相似文献
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Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness. 相似文献
12.
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly. 相似文献
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理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。 相似文献
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As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death. 相似文献
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Miao Maosheng 《华南师范大学学报(自然科学版)》2014,(6)
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula- 相似文献
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Yang Weitao 《华南师范大学学报(自然科学版)》2014,46(6):137-138
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re- 相似文献
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Bernard Kirtman 《华南师范大学学报(自然科学版)》2014,(6)
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that 相似文献
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Michael Springborg 《华南师范大学学报(自然科学版)》2014,(6):136
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the 相似文献
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《上海师范大学学报(自然科学版)》2014,(5):550
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with 相似文献