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Automated machine learning for rainfall-induced landslide hazard mapping in Luhe County of Guangdong Province,China
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作者 Tao Li Chen-chen Xie +3 位作者 Chong Xu Wen-wen Qi Yuan-dong Huang Lei Li 《China Geology》 CAS CSCD 2024年第2期315-329,共15页
Landslide hazard mapping is essential for regional landslide hazard management.The main objective of this study is to construct a rainfall-induced landslide hazard map of Luhe County,China based on an automated machin... Landslide hazard mapping is essential for regional landslide hazard management.The main objective of this study is to construct a rainfall-induced landslide hazard map of Luhe County,China based on an automated machine learning framework(AutoGluon).A total of 2241 landslides were identified from satellite images before and after the rainfall event,and 10 impact factors including elevation,slope,aspect,normalized difference vegetation index(NDVI),topographic wetness index(TWI),lithology,land cover,distance to roads,distance to rivers,and rainfall were selected as indicators.The WeightedEnsemble model,which is an ensemble of 13 basic machine learning models weighted together,was used to output the landslide hazard assessment results.The results indicate that landslides mainly occurred in the central part of the study area,especially in Hetian and Shanghu.Totally 102.44 s were spent to train all the models,and the ensemble model WeightedEnsemble has an Area Under the Curve(AUC)value of92.36%in the test set.In addition,14.95%of the study area was determined to be at very high hazard,with a landslide density of 12.02 per square kilometer.This study serves as a significant reference for the prevention and mitigation of geological hazards and land use planning in Luhe County. 展开更多
关键词 Landslide hazard Heavy rainfall Harzard mapping Hazard assessment Automated machine learning Shallow landslide Visual interpretation Luhe county Geological hazards survey engineering
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Machine Learning and Statistical Analysis in Groundwater Monitoring for Total Dissolved Solids Assessment in Winkler County, Texas
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作者 Azuka I. Udeh Osayamen J. Imarhiagbe +2 位作者 Erepamo J. Omietimi Abdulqudus O. Mohammed Oluwatomilola Andre-Obayanju 《Journal of Geoscience and Environment Protection》 2024年第6期1-29,共29页
This research aims to develop reliable models using machine learning algorithms to precisely predict Total Dissolved Solids (TDS) in wells of the Permian basin, Winkler County, Texas. The data for this contribution wa... This research aims to develop reliable models using machine learning algorithms to precisely predict Total Dissolved Solids (TDS) in wells of the Permian basin, Winkler County, Texas. The data for this contribution was obtained from the Texas Water Development Board website (TWDB). Five hundred and ninety-three samples were obtained from two hundred and ninety-eight wells in the study area. The wells were drilled at different county locations into five aquifers, including Pecos Valley, Dockum, Capitan Reef, Edward Trinity, and Rustler aquifers. A total of fourteen different water quality parameters were used, and they include Potential hydrogen (pH), Sodium, Chloride, Magnesium, Fluoride, TDS, Specific Conductance, Nitrate, Total Hardness, Calcium, Temperature, Well Depth, Sulphate, and Bicarbonates. Four machine learning regression algorithms were developed to get a good model to help predict TDS in this area: Decision Tree regression, Linear regression, Support Vector Regression, and K-nearest neighbor. The study showed that the Decision Tree produced the best model with attributes like the coefficient of determination R2 = 1.00 and 0.96 for the training and testing, respectively. It also produced the lowest score of mean absolute error MAE = 0.00 and 0.04 for training and testing, respectively. This study will reduce the cost of obtaining different water quality parameters in TDS determination by leveraging machine learning to use only the parameters contributing to TDS, thereby helping researchers obtain only the parameters necessary for TDS prediction. It will also help the authorities enact policies that will improve the water quality in areas where drinking water availability is a challenge by providing important information for monitoring and assessing groundwater quality. 展开更多
关键词 Machine learning Regression Aquifers Winkler county SINKHOleS
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Current Status and Challenges of the Water and Soil Conservation in Hotan County, Xinjiang
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作者 Junhui WANG Lei ZHANG 《Meteorological and Environmental Research》 2024年第3期72-76,共5页
In order to thoroughly analyze the current status and challenges faced by the water and water conservation in Hotan County of Xinjiang,the use situation of water resources,the effectiveness and shortcomings of water a... In order to thoroughly analyze the current status and challenges faced by the water and water conservation in Hotan County of Xinjiang,the use situation of water resources,the effectiveness and shortcomings of water and soil conservation work in the region are reviewed.Hotan County has achieved several remarkable achievements in the soil and water conservation project,daily management and maintenance,and ecological restoration projects.Some measures,such as terrace construction,slope protection engineering,and the construction of windproof and sandwood belts,have also had a positive impact on improving the quality of surface water resources while effectively curbing soil erosion.But there are also lack of operating policy detailed rules and implementation plans,and planning and design of some water and soil conservation projects lack of integrity and systematicness,application and promotion of new technologies,and soil loss management and ecological recovery effect assessment lack of comprehensive assessment indicators and methods.It has caused some water and soil conservation works to fail to be effectively implemented.In this regard,countermeasures and suggestions are put forward,such as strengthening the planning and management of water and soil conservation,promoting the technology and measures of water and soil conservation,increasing investment and funding support,and strengthening publicity education and personnel training. 展开更多
关键词 Hotan county Water and soil conservation STATUS CHALleNGE
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The Evolutionary Characteristics of the Temperature in Typical Counties in Southwest China——Taking Meitan County in Guizhou Province as an Example 被引量:2
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作者 冯婧 秦天玲 +1 位作者 高宇 李立新 《Agricultural Science & Technology》 CAS 2011年第7期1050-1054,共5页
Based on the method of linear trending,analysis was made upon the daily temperature statistics of Meitan County from 1951 to 2009,and the results showed that the temperature in general was on the rise.With 1980 as the... Based on the method of linear trending,analysis was made upon the daily temperature statistics of Meitan County from 1951 to 2009,and the results showed that the temperature in general was on the rise.With 1980 as the turning point,it was on the decline before while later the temperature increased quickly.Among these figures,the variation rates of annual average temperature,annual maximum temperature,and annual minimum temperature are 0.11 ℃/10 a,0.08 ℃/10 a,and 0.36 ℃/10 a.The variation rates of average temperature in spring,summer,fall and winter are respectively 0.12 ℃/10 a,0.07 ℃/10 a,0.12 ℃/10 a,and 0.13 ℃/10 a.Morlet wavelet was adopted to analyze the periodicity of temperature change which has periods of different scales.But since 2000,during different time scales most of the areas have been in the period of temperature rises.Besides,certain rule exists in the periodicity of maximum temperature and minimum temperature.Before 1970s,they had opposite changing rules,and the alteration of the peak value occurred.However,in the late 1980s,they had similar changing rules,and their peak values appeared at the same time.It means that against the background of global warming,the reaction of temperature evolution in Meitan County is quite remarkable. 展开更多
关键词 Meitan county Evolutionay characteristics of the temperature Morlet wavelet Linear regression
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SWOT Analysis of Tourist Resources in Underdeveloped Counties—With Pingle County in Guilin City as the Study Case
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作者 李敦祥 李志献 《Journal of Landscape Research》 2010年第12期108-111,共4页
Strengths,weaknesses,opportunities and threats of tourism development in Pingle County were analyzed to give a pertinent guide for its under developed tourism industry and economy,moreover,suggestions were proposed fo... Strengths,weaknesses,opportunities and threats of tourism development in Pingle County were analyzed to give a pertinent guide for its under developed tourism industry and economy,moreover,suggestions were proposed for the further development of local tourist resources. 展开更多
关键词 UNDERDEVELOPED counties TOURIST RESOURCES Development
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弗朗索瓦·邦的数字写作及其启示——以Le Tiers Livre网站为例
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作者 曹丹红 《语言与文化论坛》 2024年第1期71-81,共11页
弗朗索瓦·邦是较早利用网络技术进行数字实践与数字写作的法国当代作家。他在自创的Le Tiers Livre网站进行了形式多样的数字写作:添加对作品的总体评论;通过超链接形式在不同作品之间建立联系;续写;纸质版与网络版作品互为补充;... 弗朗索瓦·邦是较早利用网络技术进行数字实践与数字写作的法国当代作家。他在自创的Le Tiers Livre网站进行了形式多样的数字写作:添加对作品的总体评论;通过超链接形式在不同作品之间建立联系;续写;纸质版与网络版作品互为补充;通过添加对作品整体与局部的详细评论变旧书为新作;等等。通过不断评论、修改、续写、利用自己的旧文本,邦在旧作品的基础上获得了全新的作品,实现了文学创作形式的更新,同时也推动人们在技术时代对文学创作与观念进行更为深入的反思。 展开更多
关键词 弗朗索瓦·邦数字写作 le Tiers Livre
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基于RANS/LES混合方法的三维L型弯管流场特性数值模拟
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作者 陈喆 仝哲 +1 位作者 韩盼盼 尤云祥 《船舶工程》 CSCD 北大核心 2024年第6期138-143,152,共7页
L型弯管是船用典型部件,可实现流体质量输运和热量交换等功能。由于弯曲段曲率的影响,其内部流动十分复杂。传统的雷诺平均方法(RANS)无法模拟弯曲段的复杂流动,而大涡模拟方法(LES)则计算量太大。为此,采用RANS/LES混合方法对经典L型... L型弯管是船用典型部件,可实现流体质量输运和热量交换等功能。由于弯曲段曲率的影响,其内部流动十分复杂。传统的雷诺平均方法(RANS)无法模拟弯曲段的复杂流动,而大涡模拟方法(LES)则计算量太大。为此,采用RANS/LES混合方法对经典L型弯管进行数值模拟研究,该方法在近壁面区域采用RANS方法,在湍流核心区采用LES方法,不仅可保持模拟精度,而且网格需求量较低更适用于工程应用。针对商软中的2类RANS/LES方法——脱体涡方法(IDDES)及应力混合涡模拟(SBES)方法,比较分析其在L型弯管内部流场仿真方面的优劣,并同时考虑流向曲率修正的影响。结果表明:SBES方法对弯管内二次流(迪恩涡)的预测能力优于IDDES方法,且曲率修正模型可进一步改善SBES方法的仿真结果。 展开更多
关键词 雷诺平均/大涡模拟混合方法 L型弯管 流向曲率修正 脱体涡方法 应力混合涡模拟
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三江源国家公园土壤保持实物量计算——基于CSLE模型
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作者 李鹏飞 徐佳敏 +4 位作者 马俊杰 程捷 刘晓鸿 曹银贵 王滋贯 《国家公园(中英文)》 2024年第6期362-372,共11页
土壤保持能力是生态产品价值中可调节产品的重要组成部分,在土壤侵蚀控制及生态环境改善方面具有关键作用。自我国开展国家公园体制以来,其对于三江源地区的土壤侵蚀模数及土壤保持能力的影响尚不明确。对比CSLE与USLE模型及其因子的差... 土壤保持能力是生态产品价值中可调节产品的重要组成部分,在土壤侵蚀控制及生态环境改善方面具有关键作用。自我国开展国家公园体制以来,其对于三江源地区的土壤侵蚀模数及土壤保持能力的影响尚不明确。对比CSLE与USLE模型及其因子的差异,选取CSLE进行2000年与2020年的土壤侵蚀模数对比研究并计算黄河源区玛多县20年间土壤保持总量。结果表明:1)在研究区中,CSLE模型在区分不同土壤侵蚀模数强度时显著优于USLE模型,其对坡度坡长因子以及生物措施因子的优化计算方法可更精确地评估土壤侵蚀模数。2)从2000年至2020年,玛多县的土壤侵蚀强度得到了较大地改善,约有75%左右区域的土壤侵蚀模数具有明显下降,但仍有小部分区域的土壤侵蚀模数上升,其土壤侵蚀强度加剧。3)玛多县20年间土壤保持总量为1.683×10~6 t,在核算生态产品价值中的土壤保持量时,应以75%的土壤侵蚀模数减少的区域进行计算,而并非采用默认全区土壤均得到了有效保持的USLE公式进行计算。 展开更多
关键词 CSle 生态产品价值 土壤侵蚀模数 玛多县 三江源国家公园
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Endoscopy demand among county people in southeast China:A cross-sectional study 被引量:1
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作者 Huihui Yan Zhenghua Lin +12 位作者 Shuangjing Gao Chenyu Fan Mengyue Jiang Liying Que Lanfang Zhou Yingdi Weng Jing Shu Tongyun Zhang Jian Hu Zhiqiang Liu Xi Ye Jianting Cai Guangfa Liao 《Laparoscopic, Endoscopic and Robotic Surgery》 2023年第1期9-15,共7页
Objective The popularization of gastroenteroscopy and the introduction of comfortable medical care have further promoted the growth of people's demand,especially the demand for painless endoscopy.This cross-sectio... Objective The popularization of gastroenteroscopy and the introduction of comfortable medical care have further promoted the growth of people's demand,especially the demand for painless endoscopy.This cross-sectional study aims to investigate the current situation and change in county people's demand for endoscopy to promote the development of endoscopy centers in county hospitals in southeast China.Methods From October to December 2021,patients and their family members who came to the Gastroenterology Department in Suichang County People's Hospital of Zhejiang Province were randomly selected to complete the questionnaire.A total of 838 valid questionnaires were collected.Additionally,the original software data of the Endoscopy Center were sampled and retrieved(from October to December every year from 2018 to 2021)for statistical analysis of real-world data.Those who would choose painless endoscopy the next time in the valid questionnaires were included in the painless endoscopy group,while those who would choose ordinary endoscopy the next time were included in the ordinary endoscopy group.Results The stepwise forward binary logistic regression model analysis showed that,patients with“secondhand smoke exposure”were more willing to choose painless endoscopy(OR=1.459,95%CI:1.050-2.028,p=0.025).However,patients with an education level of“primary and below”and“junior high school”,and patients who are suffering from“currently experiencing abdominal distension”,were more willing to choose ordinary endoscopy(OR=0.270,95%CI:0.149-0.488,p<0.001;OR=0.528,95%CI:0.330-0.845,p=0.008;OR=0.536,95%CI:0.334-0.861,p=0.010).Patients with previous experience in painless endoscopy tended to choose painless endoscopy the next time,while patients with previous experience in ordinary endoscopy tended to choose ordinary endoscopy the next time(χ^(2)=140.97,p<0.001).From 2018 to 2021,the proportion of painless endoscopy has increased yearly(p<0.001).Most patients indicated that they would“regularly review gastroenteroscopy”(477/838,56.9%).Conclusions With Suichang County of Zhejiang Province as the representative,the demand for painless endoscopy for people's gastrointestinal cancer detection in southeast China has been increasing yearly.The development of endoscopy centers in county-level hospitals can basically meet the demand growth.Meanwhile,advanced concepts such as comfortable medical care and regular follow-up are gradually popularized at the grassroots level in southeast China. 展开更多
关键词 county people Comfortable medical care Painless endoscopy Endoscopic demand Cross-sectional study
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Research on Competitiveness of County Economy Based on Factor Analysis and Cluster Analysis——Taking 88 Counties in Guizhou as Samples 被引量:9
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作者 HAN De-jun,LU Jing-fang,ZHANG Wen-zhuan Guizhou College of Finance and Economics,Guiyang 550004,China 《Asian Agricultural Research》 2011年第2期28-31,共4页
17 indices are selected,such as the growth rate of total regional output value,the proportion of tertiary industry in GDP,per capita financial expenditure,and soil erosion rate of Guizhou Province in 2009.According to... 17 indices are selected,such as the growth rate of total regional output value,the proportion of tertiary industry in GDP,per capita financial expenditure,and soil erosion rate of Guizhou Province in 2009.According to the relevant indices data of statistical yearbook and governmental website,by using the method of factor analysis and the method of cluster analysis,we assess the competitiveness of county economy in 88 counties of Guizhou Province.The results show that the competitiveness of county economy in Guizhou Province is impacted by factors of location and economic foundation.In addition,the resources environment,economic structure,economic developmental speed and other factors also impact the competitiveness of county economy in Guizhou Province.Based on these,in the light of the developmental characteristics of different counties in conjunction with different developmental advantages in different regions,we should adopt different developmental strategies according to local conditions,which is significant to rapid,healthy and sustainable development of county economy in Guizhou Province. 展开更多
关键词 county ECONOMY COMPETITIVENESS FACTOR Analysis Clu
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上颌骨改良Le FortⅠ型截骨术的三维建模和术后咬合有限元分析
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作者 刘楚晴 李阳 +1 位作者 毕绍洋 林阳阳 《中国医科大学学报》 北大核心 2024年第1期46-50,共5页
目的根据CT扫描数据,基于4种软件建立光顺的上颌骨三维几何模型,模拟改良Le FortⅠ型截骨术及固定方案,对患者术后咬合情况进行有限元分析。方法使用Mimics软件初步处理CT图像,建立STL模型。将模型导入Inspire Studio软件中,建立光滑的P... 目的根据CT扫描数据,基于4种软件建立光顺的上颌骨三维几何模型,模拟改良Le FortⅠ型截骨术及固定方案,对患者术后咬合情况进行有限元分析。方法使用Mimics软件初步处理CT图像,建立STL模型。将模型导入Inspire Studio软件中,建立光滑的PolyNURBS几何模型。使用SpaceClaim软件,模拟手术截骨及钛板、钛钉固定方案。使用ANSYS Workbench软件,对术后患者咬合情况进行三维有限元分析。结果仿真结果显示,在磨牙咬合状态下有限元模型的连接关系建立准确无误。在共计6 N的咬合力作用下,钛板最大等效应力为73 MPa。结论本研究采用的上颌骨建模和分析方法可获得适用于仿真分析的光滑几何模型,有限元分析结果可以为各类正颌手术的固定方案提供参考。 展开更多
关键词 上颌骨建模 有限元分析 改良le FortⅠ型截骨术 应力分布
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Land Remediation Projects in Poverty-stricken Counties in Tibetan Areas Promoting Poverty Alleviation——A Case Study of Songpan County,Sichuan Province 被引量:2
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作者 Feng QIU Zisheng YANG 《Asian Agricultural Research》 2019年第3期55-58,61,共5页
Songpan County is a poverty-stricken county in the four provinces of China,one of the concentrated areas in China. This paper analyzes the effectiveness of land consolidation in Songpan County to promote poverty allev... Songpan County is a poverty-stricken county in the four provinces of China,one of the concentrated areas in China. This paper analyzes the effectiveness of land consolidation in Songpan County to promote poverty alleviation and development through specific cases. The results show that land remediation has improved agricultural production conditions,promoted agricultural efficiency,increased farmers' income,improved rural living conditions,promoted the development of urban and rural integration,improved the ecological environment,solved the problem that restricts the survival and development of poverty-stricken areas,enhanced the ability of farmers to develop themselves,raised the level of civilization in rural areas,and promoted poverty alleviation and development. The poverty alleviation and development has provided certain financial support for land remediation. It has promoted land remediation,and pointed out key directions for land remediation. It has an indirect promotion effect on land remediation. 展开更多
关键词 LAND REMEDIATION POVERTY alleviation POVERTY-STRICKEN areas TIBETAN areas Songpan county
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Typical Experience and Legal Problems of Urban-rural Integration Development in Counties of Chongqing
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作者 Jicheng SU 《Asian Agricultural Research》 2023年第3期17-20,25,共5页
With"people as the core",Chongqing vigorously explores the reform of integration of urban and rural elements in counties,gradually breaks down the institutional barriers that hinder the free flow and equal e... With"people as the core",Chongqing vigorously explores the reform of integration of urban and rural elements in counties,gradually breaks down the institutional barriers that hinder the free flow and equal exchange of urban and rural elements,and promotes the balanced development of land,talent,medical care,pension,education and service towards"equalization"and"integration".Some typical experience practices and outstanding results have been formed.At the same time,restricted by system,capital,technology and other factors,there are still many"pain points"and"difficulties"in the integration of urban and rural development in counties of Chongqing.Based on the reform practice,some countermeasures and suggestions for the integrated development of urban and rural elements in counties of Chongqing were put forward. 展开更多
关键词 county Development LAW MANAGEMENT
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亚临界区圆柱绕流相干结构壁面模化混合RANS/LES模型
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作者 季梦 尤云祥 +3 位作者 韩盼盼 邱小平 马乔 吴凯健 《物理学报》 SCIE EI CAS CSCD 北大核心 2024年第5期190-216,共27页
本文发展了一种具有壁面模化大涡模拟能力的雷诺平均纳维-斯托克斯(RANS)和大涡模拟(LES)方法的混合模型(简称WM-HRL模型),致力于对亚临界区雷诺数钝体绕流相干结构这类复杂流动现象进行高置信度的CFD解析模拟研究.该方法通过一个仅与... 本文发展了一种具有壁面模化大涡模拟能力的雷诺平均纳维-斯托克斯(RANS)和大涡模拟(LES)方法的混合模型(简称WM-HRL模型),致力于对亚临界区雷诺数钝体绕流相干结构这类复杂流动现象进行高置信度的CFD解析模拟研究.该方法通过一个仅与当地网格空间分布尺寸有关的湍动能解析度指标参数rk即可实现从RANS到LES的无缝快速转换,并且RANS/LES混合转换区的边界位置及其各个分区(包括RANS区、LES区及RANS/LES混合转换区)对湍动能的解析能力均可通过两个指标参数nrk1-Q和nrk2-Q准则进行预先设定.通过对雷诺数Re=3900下圆柱绕流场的系列数值模拟研究,获得了能够高置信度解析并捕捉其绕流场中三维时空瞬态发展相干结构特性的湍动能解析度指标参数nrk1-Q和nrk2-Q准则的组合条件.研究表明,该WM-HRL模型不仅能够准确获取圆柱绕流场中剪切层小尺度K-H不稳定性结构的精细谱结构,而且在同一套网格系统下通过变化湍动能解析度指标参数nrk2-Q和nrk1-Q准则的组合条件,还可以精细解析圆柱绕流场中两类不同回流区的长度结构特征,及其对应的圆柱尾部近壁面处V和U形两个平均流向速度剖面的分支结构特性. 展开更多
关键词 圆柱绕流 相干结构 KELVIN-HELMHOLTZ不稳定性 混合RANS/leS模型
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Using ArcGIS to Study Transportation Accessibility of Cultural Tourism Resources with Wan'an County in Jiangxi Province as an Example
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作者 Qing DENG 《Asian Agricultural Research》 2023年第9期40-43,共4页
This paper reviews cultural tourist attractions and transportation conditions of Wan'an County in Jiangxi Province,and calculates the accessibility and kernel density of transportation network by using ArcGIS.Thro... This paper reviews cultural tourist attractions and transportation conditions of Wan'an County in Jiangxi Province,and calculates the accessibility and kernel density of transportation network by using ArcGIS.Through the analysis,it obtains the spatial relationship between the accessibility of Wan an County and the spatial structural characteristics of"one center,two clusters,two verticals and one horizontal"presented by the cultural tourism resources.Based on this,the paper puts forward the transportation development suggestions for the development of cultural tourism for Wan'an County. 展开更多
关键词 Cultural tourism resources GIS Spatial distribution Transportation accessibility Wan'an county
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An Investigation Into the Needs and Challenges of County-Level Family Education Guidance Services and Corresponding Improvement Measures
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作者 Deng Xiaobing Tian Liyan +1 位作者 Ji Ping Yang Wei 《Contemporary Social Sciences》 2023年第3期99-116,共18页
The delivery of targeted family education guidance services is essential for establishing a three-in-one education model that encompasses families,schools,and communities.It is also the key to creating a favorable edu... The delivery of targeted family education guidance services is essential for establishing a three-in-one education model that encompasses families,schools,and communities.It is also the key to creating a favorable educational environment that promotes the comprehensive and healthy development of individual students.To gain a comprehensive understanding of family education characteristics and trends in Chinese counties,accurately tap into the educational needs of parents,and effectively identify strengths and weaknesses in family education guidance services,this paper employed a quantitative research method based on a questionnaire survey and interview data from J district of C city after years of continuous monitoring of the quality of family education in the area,aiming to explore these issues and put forward several suggestions for improvement.The results indicate that the family learning environment and atmosphere in the district are generally favorable,while parental educational competence requires further improvement.Parents express a strong desire for interactive,systematic,and fragmented family education guidance from schools.Most parents acknowledge the significance of receiving guidance on family education,yet they are disinclined to actively engage in learning-related activities.While the operational mechanisms of county-level family education guidance services have been continuously improved,there is a need for greater overall coordination.Furthermore,the potential of school-led family education guidance services has yet to be fully tapped,and the scientific and professional standards of such guidance need to be further enhanced.Based on the aforementioned findings,we propose recommendations for improvement.Using J district’s effective improvement practices in management,curriculum,and teams as an example,we intend to explore practical ways to promote county-level family education guidance services and provide a valuable reference for the establishment of a comprehensive and effective system to improve such services. 展开更多
关键词 family education family education guidance services needs and problems improvement measures county
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基于LES湍流模型的角形喷嘴数值模拟
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作者 邓富春 王尊策 +2 位作者 刘海水 李森 岳宇航 《煤矿机械》 2024年第7期203-206,共4页
针对RANS方法存在空化流场预测不准确的问题,通过采用大涡模拟(LES)对角形喷嘴进行数值模拟来获得其瞬时速度场以及空化云分布。通过对其流场进一步分析,揭示了空化水射流在发展过程中漩涡结构与空化之间的关系以及不同压力下的射流分... 针对RANS方法存在空化流场预测不准确的问题,通过采用大涡模拟(LES)对角形喷嘴进行数值模拟来获得其瞬时速度场以及空化云分布。通过对其流场进一步分析,揭示了空化水射流在发展过程中漩涡结构与空化之间的关系以及不同压力下的射流分布特征,为工程实践应用及空化射流机理提供了理论参考。 展开更多
关键词 空化水射流 漩涡 leS 流场分析
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基于WRF-LES模式的大气边界层近地风场精细化模拟研究
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作者 刘达琳 陶韬 +2 位作者 曹勇 周岱 韩兆龙 《上海交通大学学报》 EI CAS CSCD 北大核心 2024年第2期220-231,共12页
台风等极端气象灾害对工程结构安全造成严重威胁,研究近地面大气边界层精细化模拟对于土木工程具有重要应用价值.数值天气预报系统(WRF)中的大涡模拟(LES)模块具有参数方案多、精度高等优点,适用于近地面风场精细化模拟,但数值天气预报... 台风等极端气象灾害对工程结构安全造成严重威胁,研究近地面大气边界层精细化模拟对于土木工程具有重要应用价值.数值天气预报系统(WRF)中的大涡模拟(LES)模块具有参数方案多、精度高等优点,适用于近地面风场精细化模拟,但数值天气预报-大涡模拟(WRF-LES)精细化模拟效果与参数设置密切相关.寻求适用于精细化模拟近地面风场的参数设置,选用WRF-LES模式中的几种次网格模型和空间差分格式,采用较细密的网格分辨率,进行理想大气边界层模拟.对比平均风速剖面、湍流强度剖面和功率谱等风场特性,讨论关键参数对近地面风场模拟精度的影响,确定合适的参数设置.研究表明:对次网格模型,非线性回波散射和各向异性(NBA1)模型可有效改善近地面风场模拟精度;对网格方案,在计算域底部不均匀加密垂直网格可更好地描述近地面风场空间分布特征,有效减小计算资源;对空间差分格式,偶数阶差分相较奇数阶差分格式可捕获更小尺度湍流结构.所提出的WRF-LES模式参数方案,可为精细化模拟近地面风场和台风边界层提供技术参考. 展开更多
关键词 次网格模型 网格分辨率 空间差分格式 数值天气预报-大涡模拟
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Attributes of Specialized Households'Resilience and Its Impact on Rural Industrial Advancement:A Case Study of National Musical Instrument Production Specialized Households in Lankao County,Henan,China
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作者 WU Nalin WEI Yike +4 位作者 FAN Sizhe LI Li SUN Yufan ZHANG Yan SHU Yan 《Chinese Geographical Science》 SCIE CSCD 2024年第3期383-400,共18页
Specialized households serve as the primary units within specialized villages in China,and their capacity to withstand risks and external influences significantly shapes the future trajectory of specialized villages a... Specialized households serve as the primary units within specialized villages in China,and their capacity to withstand risks and external influences significantly shapes the future trajectory of specialized villages and the overall vitality of the rural economy.In this study,we established a measurement indicator system based on the definition of specialized households’resilience,elucidating the logical connection between specialized households’resilience and rural industrial development in China.The musical instrument industry in Lankao County,Henan Province of China,was employed as a case;survey data,the entropy method,and an obstacle diagnosis model were used to examine how instrument production specialized households responded to the challenges posed by Corona Virus Disease 2019(COVID-19)and the tightening of national environmental protection policies,yielding the following key findings:1)there exists substantial variation in the comprehensive resilience levels among different specialized households;2)the ability to learn and adapt is the most significant contributor to the overall resilience level of specialized households;3)technological proficiency and access to skilled talent emerge as pivotal factors influencing specialized households’resilience;4)the positioning of specialized households within the industrial supply chain and the stability of their income have a direct bearing on their resilience level.The influence of specialized households’resilience on industrial development primarily manifests in the following ways:stronger resilience correlates with increased stability in production and sales,fostering a more proactive approach to future actions.However,heightened exposure to the external macroeconomic environment can lead to a higher rate of export reduction.To enhance the development resilience of entities like specialized households and family farms,and to invigorate rural economic development,escalating investments in rural science and technology and prioritizing the training of technical talent become imperative. 展开更多
关键词 RESILIENCE specialized households rural industry Lankao county China
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Multi-level Cooperation and Complementary Advantage Poverty Alleviation Model in Poverty-Stricken Counties of Tibetan Areas:A Case Study of Songpan County in Sichuan Province
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作者 Feng QIU Zisheng YANG +1 位作者 Kai RAO Qiude LI 《Asian Agricultural Research》 2019年第10期66-75,共10页
Songpan County is a poverty-stricken county in Tibetan areas of Sichuan Province,it belongs to a concentrated poverty-stricken area in China.Through summarizing the specific conditions of multi-level cooperation and c... Songpan County is a poverty-stricken county in Tibetan areas of Sichuan Province,it belongs to a concentrated poverty-stricken area in China.Through summarizing the specific conditions of multi-level cooperation and complementary advantage poverty alleviation model in Songpan County,this paper analyzed the effect of this model.Through the analysis on the cooperative poverty alleviation model(eastern-western cooperation,provincial targeted assistance,county-wide"four-leading and four-assistance"inner-party assistance,social force"10000 enterprises helping 10000 villages",and"visiting every household and keeping every person busy"),it summarized the implementation and actual results of each level.In addition,it summarized the problems encountered in the implementation process of multi-level cooperation and complementary advantage poverty alleviation model and came up with recommendations.With the aid of this successful multi-level cooperation and complementary advantage poverty alleviation model,Songpan County has achieved a decisive victory in the fight against poverty.At the end of April 2019,the poverty rate in the whole region fell to 0.45%,and it successfully took off the poverty hat.This paper analyzed and refined the specific practice,main achievements,successful experience,implications and reference significance of multi-level cooperation and complementary advantage poverty alleviation model,to provide necessary references for innovation of poverty alleviation model in poverty-stricken Tibetan areas,or even other similar provinces and regions. 展开更多
关键词 MULTI-leVEL COOPERATION POVERTY alleviation ACHIEVEMENTS POVERTY-STRICKEN county in Tibetan areas Songpan county
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