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Reconstruction of Ore-controlling Structures Resulting from Magmatic Intrusion into the Tongling Ore Cluster Area during the Yanshanian Epoch 被引量:13
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作者 DENG Jun WANG Qingfei +5 位作者 YANG Liqiang GAO Bangfei HUANG Dinghua LIU Yah XU Hao JIANG Shaoqing 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2007年第2期287-296,共10页
The Tongling ore cluster area experienced intensive compression and associated shearing during the Indosinian-Yanshanian Epoch, which formed a trunk ore-controlling fold and fault system in the caprock. The magmatic i... The Tongling ore cluster area experienced intensive compression and associated shearing during the Indosinian-Yanshanian Epoch, which formed a trunk ore-controlling fold and fault system in the caprock. The magmatic intrusion in the Yanshanian Epoch induced a multi-stage unmixing of poly-phase fluids, resulting in mineralization characterized by multi-layer, wide-range, and multiform styles. The magmatic intrusion in the Tongling area not only supplied the essential ore-forming materials, but also reconstructed the ore-controlling structures according to a trend surface simulation of the following five strata boundaries: Silurian-Devonian, Devonian-Carboniferous, Carboniferous- Permian, Middle Permian-Upper Permian and Permian -Triassic. The result of this simulation shows that there exists a significant difference between the strata in the upper part and those in the lower. The lower trend surfaces are antiform whereas the upper trend surfaces are synform. In addition, superposing of the trend surfaces of adjacent bed boundaries (such as, Silurian-Devonian boundary superposed upon Devonian-Carboniferous boundary) shows that the lower trend surface always pierces the one above. Moreover, the position and orientation of the pierced parts of the different superposed trend surfaces are similar and show E-W-trending zonal distribution in accordance with the distribution of the regional E-W-trending magmatic-metallogenic belt. Based on comprehensive analysis of the mechanical properties of the strata, structural deformation mechanisms, and field phenomena, it seems that the special characteristics of the stratal trend surface resulted from jacking due to magmatic intrusion into the caprock previously controlled by an E-W-trending basement fault. Therefore, it is deduced that the major ore-controlling structures, which formed during regional horizontal compression, were reconstructed by the vertical jacking function of ore-forming magmas during the Yanshanian Epoch. During the ore-forming process, the local vertical jacking of magmas, coupled with the regional horizontal compression, optimized an extensive environment in the fluid- conduit network and accelerated the unmixing of poly-phase fluids following magmatic emplacement. Jacking also strengthened the vertical and lateral fluid-guiding structures, supplying more suitable physical conditions for multi-layer emplacement and wide-ranging transport of poly-phase fluids. 展开更多
关键词 magma trend surface multi-layer mineralization UNMIXING Tongling ore cluster area YANSHANIAN
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Division of hydroclimatic area over China seas—Ⅱ.Cluster analysis and fuzzy ISODATA. 被引量:2
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作者 Chen Shangji and Yao Shiyu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1994年第2期213-224,共12页
In this paper, the tree cluster analysis and ISODATA of fuzzy cluster are made on the basis of the results(Chen et al, 1993) obtained by using the principal component analysis based on the hydroclimatic values over th... In this paper, the tree cluster analysis and ISODATA of fuzzy cluster are made on the basis of the results(Chen et al, 1993) obtained by using the principal component analysis based on the hydroclimatic values over the years of the China seas,where the climatic field may be divided into three climatic zones, 9 hydroclimatic regions and 1 climatic subregion Comparison of the distribution characteristics of hydrologic seasons with those of marine fauna and flora indicates that each climatic region possesses its inherent seasonal characteristics and biota distribution, and corresponds with each other. This fact proves that the division of the above-mentioned 10 climatic regions is reliable. 展开更多
关键词 China seas division of hydroclimatic area cluster ISODATA fuzzy cluster
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Fault Detection Based on Hierarchical Cluster Analysis in Wide Area Backup Protection System 被引量:2
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作者 Yagang ZHANG Jinfang ZHANG +1 位作者 Jing MA Zengping WANG 《Energy and Power Engineering》 2009年第1期21-27,共7页
In wide area backup protection of electric power systems, the prerequisite of protection device's accurate, fast and reliable performance is its corresponding fault type and fault location can be discriminated qui... In wide area backup protection of electric power systems, the prerequisite of protection device's accurate, fast and reliable performance is its corresponding fault type and fault location can be discriminated quickly and defined exactly. In our study, global information will be introduced into the backup protection system. By analyzing and computing real-time PMU measurements, basing on cluster analysis theory, we are using mainly hierarchical cluster analysis to search after the statistical laws of electrical quantities' marked changes. Then we carry out fast and exact detection of fault components and fault sections, and finally accomplish fault isolation. The facts show that the fault detection of fault component (fault section) can be performed successfully by hierarchical cluster analysis and calculation. The results of hierarchical cluster analysis are accurate and reliable, and the dendrograms of hierarchical cluster analysis are in intuition. 展开更多
关键词 WIDE area BACKUP protection PHASOR MEASUREMENT unit PMU WIDE area MEASUREMENT system WAMS fault detection cluster analysis
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基于local-area的Internet路由级拓扑抽象算法 被引量:4
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作者 李乔 张兆心 《高技术通讯》 CAS CSCD 北大核心 2011年第9期922-927,共6页
通过分析Internet的本地聚集特性,给出了local-area和connect—area的定义,并基于此,为提高并行网络模拟性能,提出一种新型拓扑抽象算法——基于local—area的拓扑抽象(TABLA)算法。TABLA算法在给定的聚合粒度下,迭代搜索网络内... 通过分析Internet的本地聚集特性,给出了local-area和connect—area的定义,并基于此,为提高并行网络模拟性能,提出一种新型拓扑抽象算法——基于local—area的拓扑抽象(TABLA)算法。TABLA算法在给定的聚合粒度下,迭代搜索网络内的local-area,对拓扑进行抽象。模拟结果表明在Internet路由级拓扑上采用该算法,拓扑规模大约压缩为原先的45%,初始化内存节省约60%,模拟运行时间约缩短80%,大幅度提高了并行网络模拟性能。 展开更多
关键词 并行网络模拟 拓扑抽象 聚合粒度 本地域(local-area)
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使用Pluswell Cluster实现双机热备 被引量:1
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作者 彭英 季飞 《科技广场》 2009年第3期58-59,共2页
本文论述了双机热备实验在SAN网络基础课程中的重要性,阐述了利用Pluswell Cluster模拟双机热备实验的优势,并给出了实际的实验环境和步骤。
关键词 存储区域网 双机热备实验
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Dry/wet climate zoning and delimitation of arid areas of Northwest China based on a data-driven fashion 被引量:9
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作者 QingLing GENG PuTe WU +2 位作者 QingFeng ZHANG XiNing ZHAO YuBao WANG 《Journal of Arid Land》 SCIE CSCD 2014年第3期287-299,共13页
The division of arid areas is important in water and land resources management, planning and for a long-term agricultural, economic and social planning. Northwest China (NW) dominates the main arid areas in China. T... The division of arid areas is important in water and land resources management, planning and for a long-term agricultural, economic and social planning. Northwest China (NW) dominates the main arid areas in China. There is thus a need to adopt adequate concepts relative to the scope of arid areas of NW China and identify its climate types and characteristics. In this study, we analyzed climatic data over the last 30 years (1981-2010) from 191 stations in three provinces and three autonomous regions of NW China. The factor-cluster analysis technique (FC), an objective and automated method was employed to classify the dry/wet climate zones. The traditional methods with predefined thresholds were adopted for providing a comparison with FC. The results showed that the wet/dry climate zones by FC were mainly distributed along mountains, rivers and desert borders. Climate-division boundaries relied heavily on the major terrain features surrounding the grouped stations. It also showed that the climate was dry in the plain sandy areas but relatively wet in the high mountain areas. FC method can reflect the climate characteristics more fully in NW China with varied and complicated topography, and outperform the tradi- tional climate classifications. Arid areas of NW China were defined as four climate types, including five resultant classes in FC classifications. The Qinling and Da Hinggan Mountains were two important boundaries, besides main administrative boundaries. The results also indicated that there are some differences between two traditional clas- sifications. The precipitation moved and fluctuated to an extent, which confirmed that climate change played an important role in the dry/wet climate zoning, and the boundaries of dry/wet climate zones might change and migrate with time. This paper is expected to provide a more in-depth understanding on the climate characteristics in arid areas of NW China, and then contribute to formulate reasonable water and land management planning and agri- cultural production programs. 展开更多
关键词 arid areas CLASSIFICATIONS climate zoning factor-cluster analysis
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Regionalization of River Basins Using Cluster Ensemble 被引量:1
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作者 Sangeeta Ahuja 《Journal of Water Resource and Protection》 2012年第7期560-566,共7页
In the wake of global water scarcity, forecasting of water quantity and quality, regionalization of river basins has attracted serious attention of the hydrology researchers. It has become an important area of researc... In the wake of global water scarcity, forecasting of water quantity and quality, regionalization of river basins has attracted serious attention of the hydrology researchers. It has become an important area of research to enhance the quality of prediction of yield in river basins. In this paper, we analyzed the data of Godavari basin, and regionalize it using a cluster ensemble method. Cluster Ensemble methods are commonly used to enhance the quality of clustering by combining multiple clustering schemes to produce a more robust scheme delivering similar homogeneous basins. The goal is to identify, analyse and describe hydrologically similar catchments using cluster analysis. Clustering has been done using RCDA cluster ensemble algorithm, which is based on discriminant analysis. The algorithm takes H base clustering schemes each with K clusters, obtained by any clustering method, as input and constructs discriminant function for each one of them. Subsequently, all the data tuples are predicted using H discriminant functions for cluster membership. Tuples with consistent predictions are assigned to the clusters, while tuples with inconsistent predictions are analyzed further and either assigned to clusters or declared as noise. Clustering results of RCDA algorithm have been compared with Best of k-means and Clue cluster ensemble of R software using traditional clustering quality measures. Further, domain knowledge based comparison has also been performed. All the results are encouraging and indicate better regionalization of the Godavari basin data. 展开更多
关键词 K-MEANS cluster ENSEMBLE HYDROLOGY RUNOFF CULTIVATION area Precipitation Field Capacity
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血清中的免疫炎症生物标志物与慢性湿疹病人的疾病严重程度相关性研究 被引量:1
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作者 秦宗碧 李伶华 +4 位作者 蔡翔 邱百怡 王首帆 徐爱琴 朱立宏 《安徽医药》 CAS 2024年第6期1182-1186,共5页
目的探讨慢性湿疹病人血清免疫炎症生物标志物与疾病严重程度的相关性。方法将2021年9月至2022年8月于武汉市中医医院接受治疗的100例慢性湿疹病人纳入研究,包括局限性湿疹69例、泛发性湿疹31例;根据疾病严重程度分为轻度组37例、中度... 目的探讨慢性湿疹病人血清免疫炎症生物标志物与疾病严重程度的相关性。方法将2021年9月至2022年8月于武汉市中医医院接受治疗的100例慢性湿疹病人纳入研究,包括局限性湿疹69例、泛发性湿疹31例;根据疾病严重程度分为轻度组37例、中度组34例和重度组29例;将同期该院40例健康体检者纳入对照组。采用酶联免疫吸附测定检测血清免疫炎症生物标志物白细胞介素(IL)-2、IL-4、IL-5、IL-6、γ干扰素(IFN-γ)、IL-10、IL-17、IL-18、IL-23、IL-33、肿瘤坏死因子α(TNF-α)水平;采用流式细胞仪检测外周血分化抗原(CD)4+、CD8+水平;采用Pearson相关分析慢性湿疹病人血清免疫炎症生物标志物与湿疹面积及严重度指数(EASI)评分的相关性。结果对照组、轻度组、中度组、重度组慢性湿疹病人血清IL-2[(10.51±2.10)μg/L比(12.94±2.26)μg/L比(15.03±2.34)μg/L比(17.94±2.56)μg/L]、IL-4、IL-5、IL-6、IL-10、IL-17、IL-18、IL-23、IL-33、TNF-α、IFN-γ、CD8+依次升高,CD4+[(43.24±6.79)%比(37.04±4.25)%比(29.12±2.78)%比(25.62±2.35)%]依次降低(P<0.05)。局限性与泛发性慢性湿疹病人血清IL-2、IL-4、IL-5、IL-6、IL-10、IL-17、IL-18、IL-23、IL-33、TNF-α、IFN-γ、CD4+、CD8+差异无统计学意义(P>0.05)。慢性湿疹病人EASI评分与血清IL-2、IL-4、IL-5、IL-6、IL-10、IL-17、IL-18、IL-23、IL-33、TNF-α、IFN-γ、CD8+呈正相关,与CD4+呈负相关(P<0.05)。结论血清免疫炎症生物标志物与慢性湿疹病人病情严重程度存在显著相关性,可考虑将各指标作为病情评估的相关辅助指标,在临床中推广应用。 展开更多
关键词 湿疹 免疫 炎症 分化抗原 严重度指数
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Clustering Analysis of the Climate in Tobacco Planting Zone of Yunnan
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作者 JIN Ya-bo QU Ran +1 位作者 LI Tian-fu WEI Jian-yu 《Meteorological and Environmental Research》 CAS 2012年第12期77-84,共8页
[Objective] The research aimed to study clustering of the six climatic factors in Yunnan tobacco planting zone. [Method] 6 meteorological elements in 89 tobacco-growing counties and 12 sub-prefectures were conducted c... [Objective] The research aimed to study clustering of the six climatic factors in Yunnan tobacco planting zone. [Method] 6 meteorological elements in 89 tobacco-growing counties and 12 sub-prefectures were conducted clustering analysis. According to indicator and climate characteristics of the each type, climate in tobacco planting area of Yunnan Province was divided. [Result] Climate in tobacco planting area of Yunnan Province could be divided into eight types: Jiangchuan (24 counties, belonged to northern and central subtropical climate belts), Songming (27 counties, belonged to northern subtropical and central, south, north temperate climate belts), Tengchong (3 counties, belonged to northern subtropical climate belt), Mile (12 counties, belonged to central and southern subtropical climate belts), Qiubei (11 counties, belonged to southern subtropical climate belt), Yanjin (4 counties, belonged to central subtropical humid climate belt), Yuanjiang (4 counties, belonged to southern subtropical and northern tropical climate belts), Zhenxiong (3 counties, belonged to warm temperate and northern subtropical climate belts) were eight representatives. Among 1-8 eco-zones, domestic and foreign cities where climate reached level-one similarity were respectively 3, 1, 1, 0, 1, 1, 0 and 1, up to level-two similarity, respectively 12, 15, 3, 13, 13, 1, 5 and 3. Among 8 major ecological zones, similar distance of the city reaching level-one similarity was in the range of 0.28 to 0.45, and similar degree was the highest. Variety introduction among these places would be successful. Similar distance of the city reaching level-two similarity was between 0.51 and 1.00, and similar degree was higher. Mutual variety introduction had high successful rate in these places. [Conclusion] The research provided theoretical basis for selecting new suitable tobacco variety and optimizing tobacco variety layout in different zones. 展开更多
关键词 Tobacco growing area System clustering Climatic zoning YUNNAN China
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一种基于证据多视角的模糊C-means聚类算法
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作者 马宗方 李雷华 田鸿朋 《控制工程》 CSCD 北大核心 2024年第8期1345-1354,共10页
针对传统多视角聚类算法难以准确识别噪声和有效划分类间重叠区域样本的问题,提出一种基于证据多视角的模糊C均值(evidential multi-view fuzzy C-means,EMVFCM)聚类算法。首先,在证据推理框架下,研究一种改进的模糊C-means多视角聚类算... 针对传统多视角聚类算法难以准确识别噪声和有效划分类间重叠区域样本的问题,提出一种基于证据多视角的模糊C均值(evidential multi-view fuzzy C-means,EMVFCM)聚类算法。首先,在证据推理框架下,研究一种改进的模糊C-means多视角聚类算法,通过优化改进的目标函数获得待测样本属于单类和噪声的信任值,从而识别出噪声数据。然后,由于重叠区域的样本不能被准确地划分类别,所以将其划分到相对应的复合类,这不仅能够表征数据样本类别的不精确性,还能降低错误分类的风险。最后,通过人工数据集和UCI数据集验证本文算法的性能并与相关算法对比。实验结果表明,本文算法较传统多视角聚类算法能更有效地处理数据中的噪声和重叠样本难以准确划分的问题。 展开更多
关键词 多视角聚类 重叠区域 证据推理 复合类
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A Neighborhood Analysis of Underage Tobacco Sales within the Serving Area of a Canadian Public Health Unit
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作者 Saber Fallahpour Tanya Navaneelan +1 位作者 Kristy McBeth Prithwish De 《Open Journal of Statistics》 2017年第6期920-935,共16页
Despite the fact that the sale of tobacco to minors is illegal in Ontario, youth are still able to purchase tobacco. This study aims to determine the geographic variations of underage tobacco sales at the neighborhood... Despite the fact that the sale of tobacco to minors is illegal in Ontario, youth are still able to purchase tobacco. This study aims to determine the geographic variations of underage tobacco sales at the neighborhood level within the Windsor-Essex County Health Unit. Data were collected on all inspections of tobacco retail stores from 2007 to 2011 in the Windsor-Essex County Health Unit. Data were split into season 1 (September-February) and season 2 (March-August) to assess a possible seasonal effect. Relative risks were calculated for each dissemination area (DA) by modeling the risks in a hierarchical Bayesian fashion, incorporating appropriate random effects terms for both spatially correlated and uncorrelated random errors with adjustments for neighborhood income. The association between violation rate and proximity to a school was assessed through a buffer analysis. Elliptical analysis detected a significant cluster of high risk DAs in season 1 in Windsor (p-value = 0.022) but no significant cluster in season 2. Some DAs exhibited higher relative risks of tobacco sales to minors, however after adjusting the model for neighborhood income no excess risk was observed. The results of the buffer analysis showed that in season 1 there was a significantly higher probability (p-value = 0.045) of tobacco vendors located closer to schools to sell tobacco to minors. This analysis demonstrates the utility of a systematic approach to identifying neighborhoods with higher risks of tobacco sales to minors. The insights provided by this exploratory, ecologic study are valuable for program planning and directing tobacco enforcement efforts to high risk areas. 展开更多
关键词 TOBACCO DISSEMINATION area Bayesian Disease Mapping cluster Buffer ANALYSIS
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宁波都市区城市群的生态环境问题与森林应对策略
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作者 殷鲁秦 金佳莉 +5 位作者 姜莎莎 古琳 孙睿霖 陈玉飞 史依凡 杨玉坤 《中国城市林业》 2024年第4期100-105,共6页
2021年中欧双方联合开展了中欧绿色城镇化的城市森林应对关键技术研究项目,我国宁波都市区是长三角区域内的重要发展极核之一,其城市群建设也是该研究项目的典型案例。文章在总结宁波都市区“小城镇点状发展-大都市主导发展-城镇化高速... 2021年中欧双方联合开展了中欧绿色城镇化的城市森林应对关键技术研究项目,我国宁波都市区是长三角区域内的重要发展极核之一,其城市群建设也是该研究项目的典型案例。文章在总结宁波都市区“小城镇点状发展-大都市主导发展-城镇化高速发展”的发展历程的基础上,从区域尺度综合分析城市组团之间生态空间、森林质量与景观风貌、外来入侵植物、河流水系生态廊道、城乡居民生态福祉、平原村庄风貌等9个方面的生态环境问题,最后提出群域区生态共建共享共治、中心区生态空间查漏补缺、核心区生态服务能力提升和绿水青山变金山银山挖潜4方面的森林应对策略,以推进长三角区域生态协同、助力美丽杭州湾建设、构建宁波都市区生态安全共同体。 展开更多
关键词 宁波都市区 城市群 生态环境问题 森林应对策略
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公立医院多院区发展研究现状的可视化分析
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作者 刘春雨 詹引 +2 位作者 王霞 张梅 徐龙彪 《江苏卫生事业管理》 2024年第11期1532-1535,1558,共5页
目的:探析国内公立医院多院区发展的研究状况、热点变迁及前沿趋势,为该领域研究提供参考。方法:基于中国知网(CNKI)数据库,借助CiteSpace可视化软件对2014-2024年国内公立医院多院区发展研究文献进行可视化分析,包括发文量、作者和作... 目的:探析国内公立医院多院区发展的研究状况、热点变迁及前沿趋势,为该领域研究提供参考。方法:基于中国知网(CNKI)数据库,借助CiteSpace可视化软件对2014-2024年国内公立医院多院区发展研究文献进行可视化分析,包括发文量、作者和作者机构贡献分析、关键词聚类分析等。结果:经筛选纳入有效样本文献590篇。2014-2023年发文数量呈逐年上升趋势,发文量最多的作者主要是王大庆、刘文生、李卫平等,且多以机构内合作发文为主;发文数量最多的研究机构为华中科技大学同济医学院附属同济医院。研究热点主要为多院区、公立医院、一院多区、同质化等,且随着时间的推移,研究热点从宏观转向微观,更加关注多院区管理过程。结论:新时期研究者对公立医院多院区管理的关注度持续增强,但研究的机构和学者整体上还相对独立,缺少医院之间、地区间的交流与合作。“同质化”作为当前研究的热点还需不断深入剖析,探索建立评价指标体系;同时也需围绕多院区建设内涵,不断挖掘数据与现实案例,为实现公立医院优质资源扩容提供参考和借鉴。 展开更多
关键词 天津市 多院区 可视化 聚类分析
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云南个旧锡多金属矿集区电气石地球化学组成和硼同位素特征——对成矿流体性质和演化的约束 被引量:1
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作者 任竑宇 李超 +4 位作者 江小均 杨富成 韩嶂 芦磊 陈耀坤 《地球学报》 CAS CSCD 北大核心 2024年第4期575-590,共16页
个旧锡矿集区发育与晚白垩世高分异花岗岩有关的世界级Sn-Cu多金属矿床,其成矿物质的来源及流体演化过程一直是研究的热点和难点。个旧地区电气石广泛发育于碳酸盐岩、花岗岩及矽卡岩中,但对电气石尚未进行系统研究,电气石与成矿之间的... 个旧锡矿集区发育与晚白垩世高分异花岗岩有关的世界级Sn-Cu多金属矿床,其成矿物质的来源及流体演化过程一直是研究的热点和难点。个旧地区电气石广泛发育于碳酸盐岩、花岗岩及矽卡岩中,但对电气石尚未进行系统研究,电气石与成矿之间的关系尚未明确。本文对不同类型电气石开展了系统的岩相学观察和电子探针(EPMA)、LA-ICP-MS微量元素和硼同位素分析。结果表明,所有电气石都属于碱性电气石,TurⅠ、TurⅡ、TurⅣ为热液成因,TurⅢ为岩浆成因。岩浆电气石相比于热液电气石具有更低的Mg、Ca等元素,TurⅠ电气石高含量的Sr表明受到了围岩的混染。电气石的微量元素变化表明,从似斑状花岗岩到等粒花岗岩,随着岩浆分异程度逐渐增加,Sn在岩浆中逐渐富集,在似斑状花岗岩和接触带矽卡岩中沉淀卸载。个旧不同类型电气石具有均一的δ11B值(−15.2‰~−12.8‰),与花岗岩的组成范围一致,表明成矿物质来源均来源于花岗质岩浆。 展开更多
关键词 电气石 硼同位素 岩浆-热液型锡多金属矿床 个旧锡矿矿集区
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喀斯特峰丛洼地3个建群树种“植物-凋落物-土壤”系统氮同位素特征 被引量:1
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作者 吴凤婵 蔡国俊 +3 位作者 李安定 张红玉 张丽敏 彭熙 《贵州师范大学学报(自然科学版)》 CAS 北大核心 2024年第1期12-18,共7页
以喀斯特峰丛洼地3种常见次生林及其建群树种为研究对象,测定3种林分建群种的不同器官及凋落物、土壤的氮含量及氮同位素丰度值(δ^(15)N),探讨植物-凋落物-土壤氮含量及稳定氮同位素组成变化及内在联系。结果显示:3种次生林建群种植物... 以喀斯特峰丛洼地3种常见次生林及其建群树种为研究对象,测定3种林分建群种的不同器官及凋落物、土壤的氮含量及氮同位素丰度值(δ^(15)N),探讨植物-凋落物-土壤氮含量及稳定氮同位素组成变化及内在联系。结果显示:3种次生林建群种植物中叶片氮含量最高,茎的氮含量最低,3种次生林建群树种叶片氮含量均显著高于掉落物和土壤氮含量,0~30 cm土壤氮含量显著高于30~90 cm土壤氮含量,土壤养分主要集中于表层土壤;白栎、栓皮栎和光皮桦器官中δ^(15)N变化范围分别为-2.82‰~14.94‰、-1.37‰~9.35‰和-4.39‰~26.06‰,3种建群种器官间氮同位素组成均表现出显著差异(P<0.05);3种建群种群落表层土壤δ^(15)N差异显著,3种林分中0~30 cm土壤δ^(15)N均显著低于30~60 cm和60~90 cm的土壤,δ^(15)N可能是这些群落土壤氮循环过程中的敏感指标,光皮桦叶片氮含量略大于白栎和栓皮栎,光皮桦林土壤表层δ^(15)N大于白栎林和栓皮栎林,光皮桦可能比白栎和栓皮栎更为适应喀斯特生境。 展开更多
关键词 氮同位素 植物-凋落物-土壤 生态策略 适应机制 喀斯特峰丛洼地
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考虑压力均匀性的供水管网独立计量区域(DMA)分区优化研究
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作者 张鹏 刘嘉 邵煜 《科技通报》 2024年第2期30-37,共8页
独立计量区域(district meteredareas,DMAs)是实现城市供水管网压力管理与漏损控制的重要手段。现有的DMA分区算法无法在分区时保障分区内部的压力均衡。为解决这一问题,本文提出一种基于迭代求解DMA分区方法,在保证分区均匀性的同时,... 独立计量区域(district meteredareas,DMAs)是实现城市供水管网压力管理与漏损控制的重要手段。现有的DMA分区算法无法在分区时保障分区内部的压力均衡。为解决这一问题,本文提出一种基于迭代求解DMA分区方法,在保证分区均匀性的同时,实现分区内部压力均衡。该方法提出融合节点压力分布的节点相似矩阵,建立分区合理性评价指标,用于确定独立计量区域划分方案;在隔离阶段采用改进的多目标遗传算法,对边界管段开展隔离阀与流量计的优化布置;最后通过对上述2个过程进行循环迭代,确保最终分区方案的压力均衡。通过对实例管网的分区研究,验证改进方法的有效性和可行性。 展开更多
关键词 供水管网 独立计量分区 谱聚类算法 NSGA-Ⅱ遗传算法 压力迭代
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经济欠发达地区物流产业集群发展模式研究——以甘肃省为例
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作者 欧阳明慧 吕蕊 《物流科技》 2024年第17期96-99,共4页
物流产业集群发展可以降低物流成本,提高物流效率,推动物流业高质量发展。但是物流产业集群需要一定的条件,也有不同的模式。文章在总结了四种常见的物流产业集群模式的概念和特点后,对经济欠发达地区的物流产业集群困境做出了阐述,最... 物流产业集群发展可以降低物流成本,提高物流效率,推动物流业高质量发展。但是物流产业集群需要一定的条件,也有不同的模式。文章在总结了四种常见的物流产业集群模式的概念和特点后,对经济欠发达地区的物流产业集群困境做出了阐述,最后以甘肃省为例,分析了甘肃省物流产业集群的条件,并应用层次分析法(AHP)对甘肃省物流产业集群的模式做出了分析,得出了甘肃省在前期应该采用“区位导向型+政府主导型”为主物流产业集群模式,在后期应该采用“区位导向型+产业依附型”为主的物流产业集群模式的结论,这对经济欠发达地区的物流产业集群发展有一定的借鉴价值。 展开更多
关键词 物流产业集群 发展模式 经济欠发达地区 层次分析法
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农业产业集群形成演化与发展研究
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作者 李静 《西南林业大学学报(社会科学)》 CAS 2024年第1期46-52,共7页
基于大量文献资料,从农业产业集群的形成机制、农业产业集群的演化升级与竞争力提升、农业产业集群促进农民持续增收和农业农村发展等三个方面对国内外研究进行系统梳理分析。结果表明:农业产业集群是在优良的自然资源禀赋、优越的制度... 基于大量文献资料,从农业产业集群的形成机制、农业产业集群的演化升级与竞争力提升、农业产业集群促进农民持续增收和农业农村发展等三个方面对国内外研究进行系统梳理分析。结果表明:农业产业集群是在优良的自然资源禀赋、优越的制度安排等条件下形成的,集群的内外部合作、知识溢出、技术创新和数字经济的发展等促进了集群演化升级与竞争力提升,增加了农民收入,促进了农业农村发展。据此提出了未来可以通过更新研究方向、拓展研究内容、创新研究方法等进一步探索农业产业集群的建议,以期为农业产业集群的深入研究和进一步发展提供参考。 展开更多
关键词 农业产业集群 演化 竞争力 农业农村 机制
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基于多特征符号聚合近似和层次聚类的户变关系识别方法 被引量:1
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作者 周赣 茅欢 +2 位作者 冯燕钧 华济民 曾瑛 《电力系统自动化》 EI CSCD 北大核心 2024年第3期133-141,共9页
针对低压配电台区拓扑档案中可能存在的户变关系异常问题,文中提出了一种基于多特征符号聚合近似(MF-SAX)和层次聚类的户变关系识别方法。首先,运用符号聚合近似表达方法将用户电压时间序列转化为字符串序列,并引入电压波动系数和电压... 针对低压配电台区拓扑档案中可能存在的户变关系异常问题,文中提出了一种基于多特征符号聚合近似(MF-SAX)和层次聚类的户变关系识别方法。首先,运用符号聚合近似表达方法将用户电压时间序列转化为字符串序列,并引入电压波动系数和电压变化趋势两个附加参数对其特征表达进行强化。然后,基于编辑距离生成用户电压曲线相似性矩阵,并结合层次聚类算法实现户变关系的识别。最后,实际算例结果表明,提出的方法相比于现有方法准确率更高,误报更少,能直接应对数据缺失的情况,且具有更高的效率。 展开更多
关键词 低压配电台区 户变关系 层次聚类 拓扑识别 电压曲线相似性
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基于网约车数据的级联城市区域分析框架研究 被引量:1
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作者 于娜 李小楠 白燕娜 《河北师范大学学报(自然科学版)》 CAS 2024年第1期29-35,共7页
针对城市区域的复杂性和多变性,提出了一个级联城市区域分析框架(cascaded urban area analysis framework,CUAAF),用来对城市区域进行时空聚类分析.首先,将城市区域划分为多个地理栅格.其次,采用新的区域时空行为指标(areabehaviorinde... 针对城市区域的复杂性和多变性,提出了一个级联城市区域分析框架(cascaded urban area analysis framework,CUAAF),用来对城市区域进行时空聚类分析.首先,将城市区域划分为多个地理栅格.其次,采用新的区域时空行为指标(areabehaviorindex,ABI)评估任意2个栅格之间的相关性.接着,用Louvain算法对相应的栅格网络进行分析,得到聚类区域.在得到聚类区域后,可再次将该区域输入CUAAF框架,进行级联分析,得到更多分层信息.级联实验可以采用多种指标分析城市区域,从不同层次了解城市区域,获得更详细的城市区域信息.最后,分别用周中周末的数据做了对比实验,结果显示本文方法具有稳健性和数据敏感性. 展开更多
关键词 城市区域聚类 级联框架 复杂网络 Louvain算法
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