Moran sets and Moran classes

The purpose of this survey is to present Moran sets and Moran classes which generalize the classical selfsimilar sets from the following points: (i) The placements of the basic sets at each step of the constructions can be arbitrary; (ii) the contraction ratios may be different at each step; and (iii) the lower limit of the contraction ratios permits zero. In this discussion we will present geometrical properties and results of dimensions of these sets and classes, and discuss conformai Moran sets and random Moran sets as well.     

几何非线性与材料非线性

从基本概念出发,通过例子讨论在结构分析中产生几何非线性与材料非线性的原因,澄清关于它们必然同时出现的误解,并指出根据问题非线性的类型正确选择分析方法的重要性。     

Dimensions of a class of high-dimensional homogeneous Moran sets and Moran classes

A class of high-dimensional homogeneous Moran sets and Moran classes are introduced and some dimensional properties are studied. The Hausdorff dimension, modified lower box-counting dimension, lower and upper box-counting dimension, and packing dimension of high-dimensional homogeneous and partial homogeneous Cantor sets are determined. Moreover, a kind of fractal E is obtained, which is not regular but with the property Dimw(Ed)=dDimw(E), where w denotes any of the dimensions mentioned above.     

Dimensions of a class of high-dimensional homogeneous Moran sets and Moran class

A class of high-dimensional homogeneous Moran sets and Moran classes are introduced and some dimensional properties are studied. The Hausdorff dimension, modified lower box-counting dimension, lower and upper box-counting dimension, and packing dimension of high-dimensional homogeneous and partial homogeneous Cantor sets are determined. Moreover, a kind of fractal E is obtained, which is not regular but with the property Dimw(Ed)=dDimw(E), where w denotes any of the dimensions mentioned above.     

关于广义Moran集的重分形

在很一般的条件下，对广义Ｍｏｒａｎ集上的无穷乘积测度讨论了重ｆｒａｃｔａｌ测度分解。     

Net measure properties of Moran sets and applications

The Hausdorff and packing dimensions for a class of Moran sets are obtained.     

Z扫描法中的热致非线性和激发态非线性的数值模拟

本文用速率方程和声光方程从理论上数值模拟了纳秒领域下光学非线性材料在激发态非线性和热致非线性共同作用下的Z扫描曲线,并分析了在不同激光脉冲能量、脉冲宽度下以及在不同的溶液中这两种非线性机制相互竞争对材料的折射性质的影响。数值模拟结果的表明,随着条件的变化,材料的自聚焦或自散焦性质有可能发生转变。     

一类Moran测度的勒让德谱与q-Renyi维数

在一定条件下完全确定了一类Moran测度的勒让德谱及q-Renyi维数.     

大坝安全监测资料的非线性检验

引入了基于现代统计学中“bootstrap”理论的替代数据方法，实现了对大坝安全监测资料的非线性检验．在详细阐述了替代数据法的基本理论和实现方法基础上，通过分析丰满大坝的位移监测数据，确定了位移监测数据中确实存在非线性成分，并且这种非线性不是静态非线性的测量函数所引起的，而是大坝动力系统本身非线性的表现．从而为判定大坝监测资料的非线性提供了理论依据和检验方法．     

Ecology. Global amphibian population declines

The decline and disappearance of relatively undisturbed populations of amphibians in several high-altitude regions since the 1970s suggests that they may have suffered a global decline, perhaps with a common cause or causes. Houlahan et al. examined means of trends for 936 amphibian populations and concluded that global declines began in the late 1950s, peaked in the 1960s, and have continued at a reduced rate since. Here we re-analyse their data using a method that accounts for the sampling of different populations over different time periods, and find evidence of a mean global decline in monitored populations only in the 1990s. However it is calculated, the global mean not only masks substantial spatial and temporal variation in population trends and sampling effort, but also fails to distinguish between a global decline with global causes and the cumulative effects of local declines with local causes.     

变容二极管调频的非线性及其校正

该文分析了调频测距系统中变容二极管调频振荡器调制的非线性及其对测距精度的影响。提出了一种具体的校正方法,并详尽地介绍了校正的原理、电路及机辅设计程序。经非线性校正明显地提高了测距精度。     

电子节气门仿真控制

简要介绍了电子节气门技术的发展情况、系统的典型结构和工作原理,分析了电子节气门系统机械结构中存在的非线性问题,建立了其数学模型,设计了3种控制器(PID控制器、模糊控制器、滑动模态控制器)并进行了仿真.对仿真结果进行分析表明,PID控制器的控制精度较差,而且超调严重;模糊控制器具有较好地跟踪性,但存在一定的滞后现象;滑动模态控制器具有和模糊控制器相当的跟踪性能而且滞后得到了较好的改善,可以较好地满足控制要求.     

半导体的光学非线性与光学双稳

本文是对近年来光学双稳领域的进展的简介与回顾,着重介绍了解释(?)子饱和吸收和非线性色散的二能级模型,讨论了几种测量激子吸收的实验方案,并且提出了自己的实验设计方案。