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含分数阶的灰色模型及其在地基沉降预测中的应用

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水文地质工程地质 2019年第3期46卷 124-128,137页

作者：赖文杰齐昌广郑金辉王新泉左殿军宁波大学建筑工程与环境学院浙江宁波315211 浙江大学城市学院土木工程系浙江杭州310015 交通运输部天津水运工程科学研究院岩土工程研究中心天津300456 河海大学土木与交通学院江苏南京210098

基于灰色理论建立的传统沉降预测模型均为整数阶,存在不连续、与实测数据差异较大的缺陷。鉴于此,本文以灰色模型为研究对象,通过改变模型中的整数阶微分为分数阶微分来改进灰色模型的预测效果。本模型与传统模型的最大区别在于增加了... 详细信息

基于灰色理论建立的传统沉降预测模型均为整数阶,存在不连续、与实测数据差异较大的缺陷。鉴于此,本文以灰色模型为研究对象,通过改变模型中的整数阶微分为分数阶微分来改进灰色模型的预测效果。本模型与传统模型的最大区别在于增加了分数阶阶次的识别,首先结合灰色理论得到无输入的常微分方程;接着对其引入输入项,并将常微分方程做变换得到含分数阶的微分方程;最后将该模型与实测数据进行对比,且与传统灰色理论沉降预测模型进行误差计算,发现本文建立的沉降预测模型可以较好地预测地基沉降。

关键词：高速公路灰色模型沉降预测分数阶

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基于MATLAB GUI构建电工虚拟实验

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柳州师专学报 2011年第6期26卷 122-125页

作者：蓝海江温新权潘晓明赖家胜文春明柳州师范高等专科学校物理与信息科学系广西柳州545004 重庆大学光电工程学院重庆400030

纵观现代高校教学,虚拟实验已成为加强实践教学、提高教学质量的重要手段。以构建戴维宁定理虚拟实验为例,探讨基于MATLAB GUI构建电工虚拟实验的方法。结果表明,利用MATLAB GUI构建电工虚拟实验,步骤简单、程序简洁、高效逼真。

关键词：电路理论戴维宁定理虚拟实验构建 MATLAB

Seasonal variations and mechanism for environmental control of NEE of CO_2 concerning the Potentilla fruticosa in alpine shrub meadow of Qinghai-Tibet Plateau

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Science China Earth Sciences 2006年第S2期49卷 174-185页

作者： LI Yingnian, SUN Xiaomin, ZHAO xinquan, ZHAO Liang, XU Shixiao, GU Song, ZHANG Fawei & YU Guirui Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining 810001, China Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China Graduate University of Chinese Academy of Sciences, Beijing 100049, China

The study by the eddy covariance technique in the alpine shrub meadow of the Qing-hai-Tibet Plateau in 2003 and 2004 showed that the net ecosystem carbon dioxide exchange (NEE) exhibited noticeable diurnal and annual variations, with more distinct daily changes during the warmer seasons. The CO2 emission of the shrub ecosystem culminated in April and September while the CO2 absorption capacity reached a maximum in July and August. The absorbed carbon dioxide during the two consecutive years was 231.4 and 274.8 g CO2·m-2 respectively, yielding an average of 253.1 gCO2·m-2 per year: that accounts for a large proportion of absorbed CO2 in the region. Obviously, the diurnal carbon flux was negatively related to temperature, radiation and other atmospheric factors. Still, minute discrepancies in kurtosis and duration of carbon emission/absorption were detected between 2003 and 2004. It was found that the CO2 flux in the daytime was similarly affected by photosynthetic photon flux density in both years. Temperature appears to be the most important determinant of CO2 flux: specifically, the high temperature during the plant growing season inhibits the carbon absorption capacity. One potential explanation is that soil respiration is enhanced under such condition. Analysis of biomass revealed that the annual net carbon fixed capacity of aboveground and belowground biomass was 544.0 in 2003 and 559.4 g Cm"2 in 2004, which coincided with the NEE absorption capacity (63.1 g C·m-2 in 2003 and 74.9 g C·m-2 in 2004) in the corresponding plant growing season.

关键词： Potentilla frutlcosa shrub meadow yearly meteorological conditions CO2 exchange variations meteorological factors aboveground and belowground biomass lai.