地震前兆混沌时间序列多尺度分维异常识别研究

对地震前兆观测时间序列的混沌性态及其产生的根源进行了探讨。根据小波变换良好的时、频局部化特征和分形维数的变化特征,从小波分析多尺度分解的角度出发结合分形理论探讨了地震前兆混沌时间序列的异常识别问题。对几个实例的研究表明,大多数时间段内时间序列小波变换系数的分维—尺度变化曲线呈光滑、缓慢减小变化,有异常信息时段的时间序列小波变换系数的分维—尺度变化曲线变化的主要特点是曲线具有峰值,并出现了曲线先是由高向低,然后再由低向高变化,在某一尺度处达到峰值后再缓慢减小的情况。异常出现的时间在震前约2个月至1年。将小波变换与分形理论结合起来研究地震问题,不仅开拓了地震科学研究的新领域,同时也是对小波变换及分形理论应用的延拓。     

微波辐射对净水厂污泥脱水性能及分形结构的影响

对净水厂污泥在2450MHz微波作用下的调质效果进行了研究,结果表明,污泥比阻随着微波功率的增大和辐射时间的增长而下降,700W微波辐射10min能使500ml含水率为98%的污泥比阻下降73%,经微波调质(700W,5min)后,污泥颗粒变得粗大化,30-50μm范围内的污泥颗粒数增多,平均粒径由30.73μm增加至33.29μm;污泥颗粒的分形维数由1.712提高到1.724.     

Statistical detection of multiscale landscape patterns

Detection of discontinuities in landscape patterns is a crucial problem both in ecology and in environmental sciences since they may indicate substantial scale changes in generating and maintaining processes of landscape patches. This paper presents a statistical procedure for detecting distinct scales of pattern for irregular patch mosaics using fractal analysis. The method suggested is based on a piecewise regression model given by fitting different regression lines to different ranges of patches ordered according to patch size (area). Proper shift-points, where discontinuities occur, are then identified by means of an iterative procedure. Further statistical tests are applied in order to verify the statistical significance of the best models selected. Compared to the method proposed by Krummel et al. (1987), the procedure described here is not influenced by subjective choices of initial parameters. The procedure was applied to landscape pattern analysis of irregular patch mosaics (CORINE biotopes) of a watershed within the Map of the Italian Nature Project. Results for three different CORINE patch types are herein presented revealing different scaling properties with special pattern organizations linked to ecological traits of vegetation communities and human disturbance.     

长江三角洲都市连绵区城市体系的分形特征

分形研究是现代理论地理的重要内容之一,分形维数是刻画城市体系结构的有效参数。为定量分析长江三角洲都市连绵区城市体系的分形特征,通过计算豪斯道夫维数分析了长江三角洲城市体系规模分布的分形特征,通过计算关联维数和集聚维数,从城市要素的空间相关性和城市随机集聚的向心性两方面,分析了长江三角洲都市连绵区城市体系空间结构的分形特征。测算结果表明：（1）城市体系规模结构符合位序 规模分布类型,但首位城市的垄断性还很强,处于由首位型分布向序列型分布转变的过程之中,中间位序的城市数量偏少,城市之间呈竞争发展态势;（2）城市体系空间结构呈现出均匀分布的特征,城市的空间关联性强,空间相互作用强度大。在上述结论的基础上对长江三角洲都市连绵区城市体系的优化发展提出了建议.     

鄱阳湖生态经济区城市体系空间结构分形特征分析

为探讨鄱阳湖生态经济区城市体系空间结构特征,利用分形模型,分别测算了鄱阳湖生态经济区城市体系的集聚维、网格维和关联维。研究表明：(1）南昌市和九江市在鄱阳湖生态经济区城市体系自组织演化过程中核心作用明显（集聚维数分别为1.042 5和1.151 6）,前人认为该区域城市体系具有双核结构特征,集聚维数的测算从城市自组织演化角度印证了该论点;(2）研究区城市体系在空间上以线（如公路、铁路）为轴线展布（容量维（1.035 6）、信息维（107）、关联维D→1）,区域内各主要城市之间通达性良好（牛鸦维数比Q=0.941 6）;(3）区域内城市体系系统演化动力比较单一（D1≈D0）,自组织演化过程中明显受到鄱阳湖平原水陆生态系统的驱动     

Fractal structures of single-walled carbon nanotubes in biologically relevant conditions: Role of chirality vs. media conditions

Aggregate structure of covalently functionalized chiral specific semiconducting single-walled carbon nanotubes (SWNTs) was systematically studied employing static light scattering (SLS). Fractal dimensions (D_f) of two specific chirality SWNTs—SG65 and SG76 with (6, 5) and (7, 6) chiral enrichments—were measured under four biological exposure media conditions, namely: Dulbecco’s Modified Eagle Medium (DMEM), Minimum Essential Medium (MEM), Roswell Park Memorial Institute (RPMI) 1640 medium, and 0.9% saline solution. The SWNTs exhibited chiral dependence on D_f with SG65 showing more fractal or loosely bound aggregate structures, i.e., lower D_f values (range of 2.24 ± 0.03 to 2.64 ± 0.05), compared to the SG76 sample (range of 2.58 ± 0.13 to 2.90 ± 0.08). All the D_f values reported are highly reproducible, measured from multiple SLS runs and estimated with ‘random block-effects’ statistical analysis that yielded all p values to be <0.001. The key mechanism for such difference in D_f between the SWNT samples was identified as the difference in van der Waals (VDW) interaction energies of these samples, where higher VDW of SG76 resulted in tighter packing density. Effect of medium type showed lower sensitivity; however, presence of di-valent cations (Ca²⁺) in DMEM and MEM media resulted in relatively loose or more fractal aggregates. Moreover, presence of fetal bovine serum (FBS) and bovine serum albumin (BSA), used to mimic the in vitro cell culture condition, reduced the D_f values, i.e., created more fractal structures. Steric hindrance to aggregation was identified as the key mechanism for creating the fractal structures. Also, increase in FBS concentration from 1% to 10% resulted in increasingly lower D_f values.     

微污染矿井水中微絮体的形成及分形特征

利用分形理论阐述了微污染矿井水中微絮体形成的分形生长特征,考察了微絮体形成过程中的影响因素,探讨了微絮凝机理,利用絮体的分形维数表征各影响因素对微絮体形态的作用结果,结果表明,微絮体形态与其分形维数之间具有良好的相关性,且分形维数越大,微絮体更加紧实,越易于沉降,滤后水的浊度越小;同时考察了微量铁锰离子对微絮体形态的影响,为微絮凝深床过滤工艺参数的改进提出了建议.     

高浓度悬浮液的混凝实验及机理研究

进行了高浓度悬浮液的混凝实验研究。为研究混合阶段渐变剪切速率对混凝沉降效果的影响,在混合阶段分别采用固定搅拌转速和渐变搅拌转速进行实验。在混合阶段采用固定搅拌转速,当搅拌转速为210r/min时,絮体二维分形维数最高为1.8847,悬浮液浊度最低为118NTU。采用渐变搅拌转速的方法,由210r/min开始逐渐降低搅拌转速,絮体二维分形维数最大,为1.9205,处理后悬浮液浊度最小,为107NTU。在一般混凝沉降过程的规律及模型的基础上,提出了高浓度悬浮液混凝沉降过程的物理模型。     

Economic,social and environmental dimension of sustainable competitiveness of European countries

Over the last decade, promotion of competitiveness represents one of the central goals of economic policy of most of the countries. Moreover, in recent years, the promotion of competitiveness has been seen as a way of achieving desirable changes in economy and society. While there is no unity of views in the theory regarding the conceptual definition of the phenomenon of competitiveness, it is becoming less arguable that in strictly economic terms, competitiveness is a synonym for productivity. However, it should be noted that productivity growth that is accompanied by increasing social imbalance (for example, inequality in income distribution), on the one hand, and environmental pollution, on the other hand, cannot be a guarantee of improving the competitiveness of countries in the long run. Acknowledging precisely this fact and using the data from World Economic Forum on Global Competitiveness 2013, this paper elaborates on the phenomenon of sustainable competitiveness and tests the hypothesis about the positive impact of its social and environmental dimension on the economic dimension of sustainable competitiveness that is represented by the value of the Global Competitiveness Index. The survey of 34 countries confirmed the indisputable positive impact of the social dimension of sustainability, but also variable direction of the impact of the environmental dimension of sustainability (depending on the level of GDP per capita) on the economic dimension of sustainable competitiveness of European countries in 2013.     

纳米SiO2在含阴离子表面活性剂低浊水处理中的应用

在含有阴离子表面活性剂-十二烷基硫酸钠(SDS)的6 NTU高岭土悬浊液中,改变SDS的浓度,投加纳米SiO2与聚合铝PAC进行动态混凝实验与静沉实验,借助图像分析技术与分形理论,探讨了纳米SiO2与PAC处理含SDS低浊水的作用机理、絮凝效果与形态学特征.结果表明:①纳米SiO2与SDS使高岭土粒子表面负电性增强.纳米SiO2的絮凝机理以吸附架桥为主.②纳米SiO2对SDS的去除效果优于PAC.SDS浓度越高,去除效果越显著.但纳米SiO2对无机高岭土粒子的处理能力不如PAC,PAC絮凝后的上清液浊度低.当SDS浓度增至10 mg/L时,纳米SiO2对SDS的去除率高,而PAC对SDS的絮凝能力弱,PAC对无机颗粒的去除效果也下降.③助凝剂纳米SiO2较强的吸附活性能加快PAC絮体成长为结构密实的RLCA构型,分维值高,絮凝效果好.