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Regional differences in gully network connectivity based on graph theory:a case study on the Loess Plateau,China

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Journal of Mountain Science 2023年第4期20卷 1035-1050页

作者： CHENG Jian-hua LUO Lan-hua li fa-yuan liU Lu-lu CUI ling-zhou School of Geography Nanjing Normal UniversityNanjing210023China Key Laboratory of Virtual Geographic Environment Ministry of EducationNanjing Normal UniversityNanjing210023China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing Normal UniversityNanjing210023China School of Geography and Ocean Science Nanjing UniversityNanjing210023China College of life and Environmental Science Wenzhou UniversityWenzhou325035China

Material exchange frequently occurs in gullies,and thus the relationship between a gullynetwork structure and sediment transport potential has attracted considerable ***,previous researches ignored the difficulty of material transport from sources to sinks,and did not quantify the connectivity of a network *** this study,we used a graph model structure to model gully networks of six typical sample areas in the Loess Plateau of China and quantified gully network connectivity using four indexes:average node strength,accessibility from sources to sinks,potential flow,and network structural connectivity *** show that:(1)Reflected by different quantitative indexes,the trends of gully network connectivity in different regions are *** north to south,the connectivity of a sample area first increases and then decreases.(2)The more mature gullies have stronger network *** resistance is conducive to material transport in the gullies.(3)The node connectivity index of the gully network shows a significant aggregation distribution in space,and node connectivity on the main channel is often stronger than that on the branch *** results not only deepen the understanding of the process and mechanism of loess gully geomorphic development and evolution but also provide a reference for geomorphic studies.

关键词： Graph theory Gully network Loess Plateau Connectivity Regional difference

Assessing the influence of the minimum measured diameter on forest spatial patterns and nearest neighborhood relationships

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Journal of Mountain Science 2019年第10期16卷 2308-2319页

作者： li yuan-fa YANG Hai-peng WANG Hong-xiang YE Shao-ming liU Wen-zhen Guangxi Key Laboratory of Forest Ecology and Conservation College of ForestryGuangxi UniversityNanning 530004China Xiaolongshan Research Institute of Forestry of Gansu Province Gansu Provincial Key Laboratory of Secondary Forest CultivationTianshui 530004China

Forest structure analysis is important for understanding the properties and development of a forest community,and its outcomes can be influenced by how trees are measured in sampled *** there is a general consensus on the height at which tree diameter should be measured[1.3 m:diameter at breast height(DBH)],the minimum measureddiameter(MMD)often varies in different *** this study,we assumed that the outcomes of forest structure analysis can be influenced by MMD and,to this end,we applied g(r)function and stand spatial structural parameters(SSSPs)to investigate how different MMDs affect forest spatial structure analysis in two pine-oak mixed forests(30 and 57 years old)in southwest China and one old-growth oak forest(>120years old)from northwest *** results showed that 1)MMD was closely related to the distribution patterns of forest *** distribution patterns at each observational scale(r=0-20 m)tended tobecome random as the MMD *** older the community,the earlier this random distribution pattern appeared.2)As the MMD increased,neighboring trees became more regularly distributed around a reference *** most cases,however,nearest neighbors of a reference tree were randomly distributed.3)Tree species mingling decreased with increasing diameter,but it decreased slowly in older forests.4)No correlations can be found between individual tree size differentiation and *** recommend that comparisons of spatial structures between communities would be more effective if using a unified MMD criterion.

关键词： Distribution patterns Minimum measured diameter Mixed forest Nearest neighbor analysis Species mingling Uniform angle index

聚类统计方法在高含沙水流挟沙力公式验证中的应用

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水利学报 2007年第7期38卷 852-856,865页

作者：吴腾李远发洪建胡德超清华大学水沙科学与水利水电工程国家重点实验室北京100084 黄河水利科学研究院河南郑州450000 水利部水利水电规划设计总院北京100011

本文先将挟沙力公式的计算值和实测值进行标准化,然后将聚类统计的方法运用于挟沙力公式的检验。对挟沙力公式按其计算结果的点群趋势和数值的接近程度进行定量分类,最后根据类的优劣评价不同公式。该方法既实现了从定量上对公式的评价... 详细信息

本文先将挟沙力公式的计算值和实测值进行标准化,然后将聚类统计的方法运用于挟沙力公式的检验。对挟沙力公式按其计算结果的点群趋势和数值的接近程度进行定量分类,最后根据类的优劣评价不同公式。该方法既实现了从定量上对公式的评价,又克服了因检验资料数值差异过大引起的误差。文中选取了6组高含沙水流挟沙力公式进行聚类统计,结果表明这6组公式可分为3类,第一类公式包括张红武公式,第二类包括窦国仁公式、舒安平公式,曹如轩公式和刘兴年公式;第三类公式包括刘峰公式,且第一类公式与不同水流条件的实测值符合得最好。

关键词：水流挟沙力聚类统计公式检验

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黄土高原数字地形分析研究进展

地理与地理信息科学 2017年第4期33卷 1-7页

作者：汤国安李发源熊礼阳南京师范大学虚拟地理环境教育部重点实验室江苏南京210023

黄土高原数字地形分析以我国黄土高原为研究对象,基于该区域不同尺度DEM数据提取各类坡面地形因子及特征地形要素,并通过对各种地形因子和特征要素的自身特点、空间分异规律及各因子与要素之间的相互关系建立地学统计模型,从更深层次探... 详细信息

黄土高原数字地形分析以我国黄土高原为研究对象,基于该区域不同尺度DEM数据提取各类坡面地形因子及特征地形要素,并通过对各种地形因子和特征要素的自身特点、空间分异规律及各因子与要素之间的相互关系建立地学统计模型,从更深层次探讨黄土地貌演化及其空间分异规律,深化对黄土高原的认识。该文总结了黄土高原数字地形分析的基本理论与分析方法,从该区域的DEM数据模型、地形特征要素、地形信息图谱、地形纹理、沟壑信息图谱和地貌发育演化机理等方面对黄土高原数字地形分析的研究成果进行较全面地梳理与分析。可以看出,黄土高原数字地形分析已成为数字地形分析领域独具特色的研究方向,其中很多方法均已成为地貌计量学的重要研究手段。

关键词：黄土高原数字高程模型数字地形分析

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喀斯特栎类老龄林的空间结构分析

林业科学研究 2024年第2期37卷 104-114页

作者：骆秀琼何吉安李远发广西大学林学院广西森林生态与保育重点实验室广西南宁530004 来宾金秀大瑶山森林生态系统广西野外科学观测研究站广西来宾545700

[目的]研究喀斯特栎类老龄林的分布格局、空间关联和标记特征,探明垂直分层在喀斯特森林生物多样性维系中的作用。[方法]在中国西南地区南盘江流域的喀斯特老龄林(>300 a)中建立1块面积为200 m×110 m的固定样地,依据树高和物种组分将... 详细信息

[目的]研究喀斯特栎类老龄林的分布格局、空间关联和标记特征,探明垂直分层在喀斯特森林生物多样性维系中的作用。[方法]在中国西南地区南盘江流域的喀斯特老龄林(>300 a)中建立1块面积为200 m×110 m的固定样地,依据树高和物种组分将树木划分为林分上层和林分下层,用负指数函数分析了径阶与物种多度和丰富度的数量关系,用双相关函数g(r)分析林分上层、林分下层以及它们各自主要种群的分布格局和空间关联,用标记相关函数kmm(r)分析树种和树木大小的空间分布。[结果](1)林分、林分上层和林分下层的径阶分布均呈倒J型,林分和林分下层的物种丰富度随径阶的增大而减小,而林分上层则呈先升后降的趋势;(2)林分上层在多数尺度上呈规则或随机分布,仅在小尺度(r=0~1 m、4~6 m)上表现为聚集分布,林分下层的聚集强度和尺度皆大于林分上层;(3)林分上层和林分下层之间,以及它们各自的主要种群之间均以随机关联为主,只有个别种间对在小尺度(r=0~2 m)上呈正关联或负关联;(4)林分和林分下层在所有观测尺度上表现为同种聚集,强度明显大于林分上层;林分和林分上层的个体大小分化明显,小径木聚集。林分下层的个体大小相近,在多数尺度上混生。[结论]垂直分层决定了林分上层、林分下层的物种组分、多度、分布格局和空间关联,在物种共存和多样性维持中扮演重要角色。

关键词：喀斯特老龄林垂直分层大小分化分布格局

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黄河中游流域地貌形态特征研究

地理与地理信息科学 2017年第4期33卷 107-112页

作者：李晨瑞李发源马锦刘玮南京师范大学/江苏省地理信息资源开发与利用协同创新中心江苏南京210023

黄河中游流经黄土高原的核心区域,对黄河中游流域地貌形态特征的定量分析可以反映黄河中游流域地貌演化进程以及黄土高原侵蚀地貌形态特征。该文以黄土高原区域30m分辨率的DEM为信息源,首先提取了黄河中游7条典型一级支流及其纵剖面,然... 详细信息

黄河中游流经黄土高原的核心区域,对黄河中游流域地貌形态特征的定量分析可以反映黄河中游流域地貌演化进程以及黄土高原侵蚀地貌形态特征。该文以黄土高原区域30m分辨率的DEM为信息源,首先提取了黄河中游7条典型一级支流及其纵剖面,然后计算了6种量化指标分析其流域地貌形态以及流域地貌演化进程,在此基础上,构建地貌特征综合评价指标反映黄土高原区域侵蚀地貌形态特征。实验结果表明,秃尾河、无定河以及延河发育至深切侵蚀期;窟野河发育至深切侵蚀和均衡调整之间的过渡期;汾河、洛河以及渭河发育至均衡调整期。流域地貌随河流侵蚀循环而相应演化,7条河流所在流域的地貌发育程度从北到南也基本呈现逐渐成熟的趋势。所计算的侵蚀地貌综合评价指标值显示,窟野河、秃尾河、无定河以及延河流域共同构成黄土高原强烈土壤侵蚀区;汾河、洛河以及渭河流域的土壤侵蚀程度较低。

关键词：黄河中游河流纵剖面流域地貌演化侵蚀地貌综合评价指标

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烧结机回程道上台车起拱问题的探讨

南方金属 2007年第3期 51-52页

作者：李元发珠海粤裕丰钢铁有限公司广东珠海519050

介绍了粤裕丰钢铁公司烧结厂132 m2烧结机台车起拱的原因,缓解起拱的办法.

关键词：台车起拱原因缓解办法

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黄土地貌沟沿线研究综述

地理与地理信息科学 2012年第6期28卷 44-48页

作者：张磊汤国安李发源熊礼阳南京师范大学虚拟地理环境教育部重点实验室江苏南京210046

黄土高原的沟沿线是最能体现黄土地貌形态特征的地形结构线。沟沿线的形态结构、层次级别、空间展布、发育趋势,既是黄土地貌最显著的外在表象,又深刻地映射着黄土地貌发育的内在机理。该文首先从沟沿线类型划分入手,在总结前人对线状... 详细信息

黄土高原的沟沿线是最能体现黄土地貌形态特征的地形结构线。沟沿线的形态结构、层次级别、空间展布、发育趋势,既是黄土地貌最显著的外在表象,又深刻地映射着黄土地貌发育的内在机理。该文首先从沟沿线类型划分入手,在总结前人对线状地貌特征要素分类研究的基础上,分析了现有黄土地貌沟沿线类型划分体系;其次,从定量分析的角度,对现有沟沿线的量化指标研究现状进行了分析,系统归纳和总结了沟沿线自动提取技术的特点与适应性。此外,分析了基于沟沿线的黄土地貌研究进展,并从辩证的视角阐述了沟沿线研究科学内涵与发展趋势,对当前沟沿线研究存在的问题进行了深入剖析,展望了黄土地貌数字地形分析的发展前景。

关键词：沟沿线黄土地貌 DEM

Correlation between the rock mass properties and maximum horizontal stress:A case study of overcoring stress measurements

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 39-48页

作者： Peng li Meifeng Cai Shengjun Miao yuan li Yu Wang Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mines University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Coal Resources and Safe Mining China University of Mining and TechnologyXuzhou 221116China

Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress *** investigate the correlation between the rock mass properties and maximum horizontal stress,the three-dimensional(3D)stress tensors at 89 measuring points determined using an improved overcoring technique in nine mines in China were adopted,a newly defined characteristic parameter C_(ERP)was proposed as an indicator for evaluating the structural properties of rock masses,and a fuzzy relation matrix was established using the information distribution *** results indicate that both the vertical stress and horizontal stress exhibit a good linear growth relationship with *** is no remarkable correlation between the elastic modulus,Poisson's ratio and depth,and the distribution of data points is scattered and ***,there is no obvious relationship between the rock quality designation(RQD)and *** maximum horizontal stress σ_(H) is a function of rock properties,showing a certain linear relationship with the C_(ERP)at the same *** addition,the overall change trend of σ_(H) determined by the established fuzzy identification method is to increase with the increase of C_(ERP).The fuzzy identification method also demonstrates a relatively detailed local relationship betweenσ_H and C_(ERP),and the predicted curve rises in a fluctuating way,which is in accord well with the measured stress data.

关键词： overcoring stress measurements elastic modulus Poisson's ratio rock quality designation maximum horizontal stress fuzzy identification