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Assessment on eco-environmental quality of the Yellow River Basin by considering desertification index
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作者 AN Min MENG Fan +4 位作者 HE Weijun XUE Fang SONG Mengfei XIE Ping WANG Bei 《Journal of Mountain Science》 SCIE CSCD 2024年第10期3275-3292,共18页
Desertification has had a significant impact on the ecological environment of the Yellow River Basin(YRB)in China.However,previous studies on the evaluation of the ecological environment quality(EEQ)in the YRB have pa... Desertification has had a significant impact on the ecological environment of the Yellow River Basin(YRB)in China.However,previous studies on the evaluation of the ecological environment quality(EEQ)in the YRB have paid limited attention to the indicator of desertification.It is of great significance to incorporate the desertification index into the spatiotemporal assessment of the EEQ in the YRB in order to protect the ecological environment in the region.In this study,based on multi-source remote sensing data from 91 cities in the YRB,this article proposes a desertification remote sensing ecological index(DRSEI)model,which builds upon the traditional Remote Sensing Ecological Index(RSEI)model,to analyze the spatiotemporal changes in the EEQ in the YRB from 2001 to 2021.Furthermore,using the geographic detector(GD),and geographically and temporally weighted regression(GTWR)model,the study assesses the impact of human and natural factors on the EEQ in the YRB.The research findings indicate that:(1)Compared to the traditional RSEI,the improved DRSEI shows a decreasing trend in the evaluation results of the EEQ.Among the 24 cities,the change in DRSEI exceeds 0.05 compared to RSEI,accounting for 26.37%of the YRB.The remaining 67 cities have changes within a range of less than 0.05,accounting for 73.63%of the YRB.(2)The results of the GD for individual and interactive effects reveal that rainfall and elevation have significant individual and interactive effects on the EEQ.Furthermore,after the interaction with natural factors,the explanatory power of human factors gradually increases over time.The spatial heterogeneity results of GTWR demonstrate that rainfall has a strong direct positive impact on the EEQ,accounting for 98.90%of the influence,while temperature exhibits a more pronounced direct inhibitory effect,accounting for 76.92%of the influence.Human activities have a strong negative impact on the EEQ and a weak positive impact. 展开更多
关键词 Ecological environment quality desertification index desertification remote sensing ecological index Driving factors Yellow River Basin
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Diverse responses of fungal functional groups to desertification in forest soils of Pinus densata on the Chinese Tibetan plateau
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作者 Jiani Hua Jiangbao Zhang +4 位作者 Baohan Song Tianyi Wang Jingji Li Nan Yang Lingfeng Mao 《Journal of Forestry Research》 SCIE EI CAS CSCD 2024年第5期120-130,共11页
Rapid increase in desertification is an environ-mental concern,especially for the health and sustainabil-ity of ecosystems in changing climates.How ecosystems respond to such changes may be partially understood by stu... Rapid increase in desertification is an environ-mental concern,especially for the health and sustainabil-ity of ecosystems in changing climates.How ecosystems respond to such changes may be partially understood by studying interactions and performance of critically impor-tant groups such as soil fungi functional groups.This study investigated variations in diversities of three soil fungi functional guilds(saprotrophic,symbiotic,pathogenic)and influencing abiotic factors in a Pinus densata forest on the southeast Tibetan Plateau where desertification is intense.The results indicate desertification significantly decreased the proportion of dominant fungal guild-symbiotic fungi(mean relative abundance decreasing from 97.0%to 68.3%),in contrast to saprotrophic fungi(increasing from 2.7%to 25.7%)and pathogenic(from 0.3%to 5.9%).Soil pH had the most significant impact on fungal community structure and negatively correlated with symbiotic fungal richness,which was significantly lower in arid soils,and positively correlated with saprotrophic and pathogenic fungal alpha-diversity,which were abundant.Different community struc-tures and regulators of the three fungi communities were observed,with pH,total phosphorus and ammonium(NH_(4)^(+))as the main determinants.This study links the biotic and abi-otic components during desertification and the interactions between them,and may be used as indicators of ecosystem health and for amendments to mitigate the effects of a chang-ing climate. 展开更多
关键词 desertification Fungal diversity Saprotrophs Ectomycorrhizal fungi Climate change
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Assessment of desertification sensitivity using an improved MEDALUS model in Northern China
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作者 NingJing Tan CaiXia Zhang +1 位作者 YingYing Wu ZhenTing Wang 《Research in Cold and Arid Regions》 CSCD 2024年第3期141-148,共8页
Assessment of land sensitivity to desertification is an important step to support desertification monitoring and control.Based on the Mediterranean Desertification and Land Use(MEDALUS)model,we defined four quality in... Assessment of land sensitivity to desertification is an important step to support desertification monitoring and control.Based on the Mediterranean Desertification and Land Use(MEDALUS)model,we defined four quality indicators(soil,climate,vegetation and management)to evaluate the sensitivity of land in northern China to desertification.We improved MEDALUS via excluding cities from the areas at risk of desertification by means of defining a threshold value for population density.The framework,validated in northern China,further optimizes the model to link priority areas and land restoration programmed to support desertification control.We found that the four indicators influenced and restricted each other,which jointly affected the distribution of desertification sensitivity in northern China.The spatial distribution of sensitivity in northern China showed large regional differences,with clear boundaries and concentrated distributions of regions with high and low sensitivity;the overall sensitivity decreased,with some areas rated as having moderate,severe,and extremely severe sensitivity changing to slight sensitivity;and the influence weight was much higher for the management quality index than for the climate,vegetation,and soil indexes.This suggests that management was the main factor that affected desertification sensitivity in northern China,and that climate factors exacerbated sensitivity,but the factors that are driving the spatial heterogeneity of the influencing factors need further study。 展开更多
关键词 desertification Sensitivity MEDALUS Factor analysis Northern China
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Interaction and coordinated development between desertification control and social economy in Xizang,China
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作者 ZHU Cai-xia ZHENG Yu-jie +1 位作者 LIU Si-yu QIN Tao 《Ecological Economy》 2024年第2期160-177,共18页
Based on the general requirements of the coordinated development of"ecological livable"and"affluent life"in the rural revitalization strategy,the evaluation index system of desertification control ... Based on the general requirements of the coordinated development of"ecological livable"and"affluent life"in the rural revitalization strategy,the evaluation index system of desertification control was constructed,the interaction between desertification control and regional social economy and the internal space-time coordination mechanism were explored,and the quality of desertification control and its coordination degree with regional economic development were quantitatively analyzed.The decoupling mechanism of desertification governance society economy system were analyzed,and the high level for the government to promote desertification governance,constructing ecological economy coordinated development pattern to provide decision basis to Xizang desertification governance-social economic system interaction and coupling coordination development as the research object,introducing the coupling decoupling model to measure the coupling coordination model and system coordination and decoupling decoupling.Desertification control in Xizang shows a trend of gradual improvement,but the overall level is still not high and there is a lot of room for optimization.The coupling coordination degree of desertification control-social and economic system is in a steady fluctuation trend,rising from D value less than 0.55 in 2004 to 0.87 in 2018,in a state of coordinated development(good),and grey prediction analysis shows that D value is in a continuous rise.The coupling coordination degree of the six prefecture-level cities in Xizang and Ngari region is different in time and space,but the overall development trend is coordinated.The development index of desertification control and the socio-economic development index show the interaction of strong decoupling,strong negative decoupling and weak decoupling,and there are interaction effects of desertification control,economic development and social development at different scales. 展开更多
关键词 desertification control coupling coordination model decoupling model economic development
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Impact of Vegetation Restoration on Soil Fungal Community Structure in Karst Rocky Desertification Areas
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作者 Shasha WANG Jiacheng LAN 《Meteorological and Environmental Research》 2024年第2期55-61,共7页
In this paper,managed forest(MF)and natural forest(NF)in the Huajiang Demonstration Zone of Guanling,Guizhou were selected as research objects,and cropland(CL)was taken as control.High-throughput sequencing technology... In this paper,managed forest(MF)and natural forest(NF)in the Huajiang Demonstration Zone of Guanling,Guizhou were selected as research objects,and cropland(CL)was taken as control.High-throughput sequencing technology was used to study the characteristics of fungal community composition and species diversity in the surface(0-10 cm)soil of each restoration measure,in order to reveal the dominant soil fungal groups and fungal community composition in karst rocky desertification areas,which was conducive to a more comprehensive understanding of the soil conditions of different vegetation restoration measures.Research has shown that vegetation restoration significantly affected the diversity of soil fungal community,with significant increases in Sob index,Ace index,and Chao index.The vegetation restoration has significantly changed the composition of fungal community.The dominant fungi in the CL topsoil are Sordariomycetes(62.28%),Dothideomycetes(12.34%),and Eurotiomycetes(9.12%);the dominant fungi in the MF soil are Sordariomycetes(45.05%),Dothideomycetes(14.74%),and Mortierellomycetes(10.40%);the dominant fungi in the NF soil are unclassified fungal community(26.38%),Sordariomycetes(19.78%),and Agaricomycetes(13.82%).Vegetation restoration has changed the key fungal groups in the soil.Sordariomycetes,Fusarium,and Setophoma are the key dominant fungal groups in CL soil;Dioszegia is key dominant fungal group in MF soil;c_unclassified_k_Fungi,p_unclassified_k_Fungi,o_unclassified_k_Fungi,f_unclassified_k_Fungi,g_unclassified_k_Fungi,Teichospora,and Diaporthe are key dominant fungal groups in NF soil. 展开更多
关键词 Karst rocky desertification Vegetation restoration Soil fungal community Fungal diversity
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Remote sensing monitoring of the recent rapid increase in cultivation activities and its effects on desertification in the Mu Us Desert, China
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作者 ZHAO Hongyan YAN Changzhen +1 位作者 LI Sen WANG Yahui 《Journal of Arid Land》 SCIE CSCD 2023年第7期812-826,共15页
The recent ecological improvement in the Mu Us Desert of China, largely attributed to large-scale afforestation projects, has created new opportunities for cultivation activities. However, the subsequent rapid increas... The recent ecological improvement in the Mu Us Desert of China, largely attributed to large-scale afforestation projects, has created new opportunities for cultivation activities. However, the subsequent rapid increase in reclamation on desertification land and its impact on desertification have raised concerns. In this study, we first extracted data on cultivated land and desertification land in 1975,1990, 2000, 2005, 2010, 2015, and 2020 through the human-computer interaction visual interpretation method. By overlaying the cultivated land dynamics and desertification land, we subsequently explored the effect of cultivation activities on desertification in the Mu Us Desert during the six periods from 1975 to 2020(1975–1990, 1990–2000, 2000–2005, 2005–2010, 2010–2015, and 2015–2020). The results showed that cultivated land in the Mu Us Desert showed a fluctuating and increasing trend from 3769.26 km~2 in 1975 to 4865.73 km~2 in 2020, with 2010 as the turning point for the recent rapid increase. The main contributors included the large and regular patches distributed in Yuyang District and Shenmu of Shaanxi Province, and relatively smaller patches concentrated in Inner Mongolia Autonomous Region. The increased cultivated land from the reclamation on desertification land was dominated by moderate and severe desertification lands, and the decreased cultivated land that was transferred into desertification land as abandoned cultivated land was dominated by slight and moderate desertification lands. The effect of cultivation activities on desertification reversal(average area proportion of 10.61% for reversed desertification land) was greater than that of the development of desertification(average area proportion of 5.82% for developed desertification land). Nevertheless, compared to reversed desertification land,both the significant increase of developed desertification land during the periods of 2000–2005 and 2005–2010 and the insignificant decrease during the periods of 2005–2010, 2010–2015, and 2015–2020 implied a potential remobilization risk. Therefore, this study provides a significant theoretical reference for the formulation of ecological restoration projects and regional macroeconomic development policies by considering the influence of cultivation activities, to ensure the overall environmental stability and sustainability in desertification land where reclamation and abandonment activities have taken place. 展开更多
关键词 cultivation activities desertification land desertification reversal and development RECLAMATION spatial overlay analysis Mu Us Desert
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Soil quality assessment for desertification based on multi-indicators with the best-worst method in a semi-arid ecosystem
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作者 Orhan DENGİZ İnci DEMİRAĞTURAN 《Journal of Arid Land》 SCIE CSCD 2023年第7期779-796,共18页
Since there are some signs of land degradation and desertification showing how soil sustainability is threatened, it is crucial to create a soil quality index(SQI) model in the semi-arid ?orum Basin, situated between ... Since there are some signs of land degradation and desertification showing how soil sustainability is threatened, it is crucial to create a soil quality index(SQI) model in the semi-arid ?orum Basin, situated between the Black Sea and Anatolia Region, Central Turkey. The primary aims of the study are:(1) to determine SQI values of the micro-basin in terms of land degradation and desertification.Moreover, the best-worst method(BWM) was used to determine the weighting score for each parameter;(2) to produce the soils' spatial distribution by utilizing different geostatistical models and GIS(geographic information system) techniques;and(3) to validate the obtained SQI values with biomass reflectance values. Therefore, the relationship of RE-OSAVI(red-edge optimized soil-adjusted vegetation index) and NDVI(normalized difference vegetation index) generated from Sentinel-2A satellite images at different time series with soil quality was examined. Results showed that SQI values were high in the areas that had almost a flat and slight slope. Moreover, the areas with high clay content and thick soil depth did not have salinity problems, and were generally distributed in the middle parts of the basin. However, the areas with a high slope, poor vegetation, high sand content, and low water holding capacity had low SQI values.Furthermore, a statistically high positive correlation of RE-OSAVI and NDVI indices with soil quality was found, and NDVI had the highest correlative value for June(R~2=0.802) compared with RE-OSAVI. 展开更多
关键词 soil quality land degradation desertification best-worst method remote sensing
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An Inspiring Triumph Ethiopia can learn from China’s reversing desertification and promoting a green future
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作者 ABREHAM AREBE TOLA 《ChinAfrica》 2023年第11期56-57,共2页
Minqin County,located in the arid Gansu Province of northwest China,has a remarkable story of hope and triumph.The residents of the region faced challenges due to the unrelenting expansion of desertification,which led... Minqin County,located in the arid Gansu Province of northwest China,has a remarkable story of hope and triumph.The residents of the region faced challenges due to the unrelenting expansion of desertification,which led to the degradation of their land.Determined to fight against the invading sand,the people of Minqin embarked on a great journey to reclaim their land from the desert and prevent the sand dune expansion.Despite the rapid desertification and land degradation that Minqin was facing,with unfaltering determination and well-implemented strategies,it has emerged as a shining example of how countries facing similar environmental issues,such as Ethiopia,can tackle desertification.Minqin’s desertification drive rests on its commitment to reverse the adverse impacts of desert expansion through afforestation. 展开更多
关键词 desertification rests NORTHWEST
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条块关系:理解中国府际关系的一个核心概念 被引量:2
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作者 徐东涛 《治理研究》 CSSCI 北大核心 2024年第3期34-44,158,共12页
条块结构是我国政府组织体系的基本构成,条块关系是对中国府际关系的形象化、概念化和学理化表达,是当今中国公共管理实践和理论研究的热点问题。条块关系的演变发展与国家体制的建构及其改革同频共振,在推进国家治理体系与治理能力现... 条块结构是我国政府组织体系的基本构成,条块关系是对中国府际关系的形象化、概念化和学理化表达,是当今中国公共管理实践和理论研究的热点问题。条块关系的演变发展与国家体制的建构及其改革同频共振,在推进国家治理体系与治理能力现代化的过程中,条块关系必将继续成为政府改革和公共治理的重要议题,清晰界定条块关系的内涵,系统梳理条块关系的主要争论,深化对条块关系的规律性认识,重要且迫切。从中国公共管理自主知识体系建构的视角解读中国特色条块关系,既要基于中国国家制度建设和政府改革实践的历史与现实,也要上升到公共管理研究的普遍性理论关怀。条块关系或将成为中国公共管理实践和研究贡献于公共管理普遍理论发展的重要内容。 展开更多
关键词 条块关系 府际关系 公共管理关键词 自主知识体系
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人地耦合视角下喀斯特石漠化地区生态系统服务提升
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作者 岳跃民 王克林 +4 位作者 罗为群 韦霄 李德军 张伟 吴协保 《生态学报》 CAS CSCD 北大核心 2024年第18期8159-8164,共6页
针对喀斯特石漠化治理转型面临恢复效果区域差异大、生态功能稳定性弱、忽视社会系统与生态系统的协同等问题,系统梳理了当前我国石漠化治理存在的主要挑战与科技需求,提出从侧重自然生态系统转向社会-生态系统的整体性视角,以区域生态... 针对喀斯特石漠化治理转型面临恢复效果区域差异大、生态功能稳定性弱、忽视社会系统与生态系统的协同等问题,系统梳理了当前我国石漠化治理存在的主要挑战与科技需求,提出从侧重自然生态系统转向社会-生态系统的整体性视角,以区域生态系统服务整体提升为目标,聚焦喀斯特关键带地上-地下耦合过程,加强石漠化与社会-生态过程的互馈机制、功能微生物-钙协同促进土壤碳氮高效固持机理、基岩生境植被恢复关键带水分养分保障机制等研究,突破喀斯特社会-生态系统耦合、岩溶多界面蓄水-保土协同增效、岩土组构与生态位互补的植被群落改造、生物固氮与有机废弃物高效利用的种养协调、生态-岩溶过程协同的固碳能力提升等关键技术,形成喀斯特生态产品供给能力提升与农业产业转型协同的绿色发展模式,有助于实现喀斯特区域人地耦合与生态系统服务整体提升,为西南喀斯特地区石漠化治理工程与乡村振兴提供科技支撑。 展开更多
关键词 喀斯特 石漠化 社会-生态过程 关键带 生态系统服务提升
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基于TF-IDF算法的运营商客户投诉原因研究 被引量:1
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作者 张爱华 孙嘉鸿 《北京邮电大学学报(社会科学版)》 2024年第2期39-49,共11页
针对运营商人工处理客户投诉工单高成本低效率问题,提出了一种基于TF-IDF算法的定量研究方法,旨在高效精准地识别客户投诉原因。选用Jieba分词,导入自定义词典和停用词列表,对运营商客户投诉工单进行关键词抽取,获取各类问题中TF-IDF值... 针对运营商人工处理客户投诉工单高成本低效率问题,提出了一种基于TF-IDF算法的定量研究方法,旨在高效精准地识别客户投诉原因。选用Jieba分词,导入自定义词典和停用词列表,对运营商客户投诉工单进行关键词抽取,获取各类问题中TF-IDF值排名前6的关键词,输出关键词集。提高了关键词抽取的准确性和效率。此外,对比仅对文档集使用TF进行统计和使用TextRank算法的情况,突显了IDF的重要性及算法原理的差异。实验结果表明,光猫、路由器、机顶盒问题广泛存在于各类投诉中。针对这三类问题,为运营商提供了改进产品、服务的相关建议,对运营商集中治理、解决问题具有一定的实用价值。 展开更多
关键词 投诉工单 投诉原因 关键词抽取 TF-IDF
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沙漠生态学概念、学科特色、内容及指导作用
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作者 刘任涛 孙建财 周磊 《生态学报》 CAS CSCD 北大核心 2024年第17期7892-7898,共7页
生态学是生态文明建设的理论基础。现代生态学学科发展与区域生态特色相结合,已成为生态学特色学科方向发展的显著特征和区域生态文明建设的关键依据。沙漠生态学以沙漠或沙漠化土地为研究区域,以沙漠生物为研究对象,是沙漠学与生态学... 生态学是生态文明建设的理论基础。现代生态学学科发展与区域生态特色相结合,已成为生态学特色学科方向发展的显著特征和区域生态文明建设的关键依据。沙漠生态学以沙漠或沙漠化土地为研究区域,以沙漠生物为研究对象,是沙漠学与生态学的交叉融合学科,具有典型的区域性特色。从沙漠生态学的概念和学科定位的角度,分析了沙漠生态学的学科特点和特色优势。基于此,沙漠生态学具有自己的研究范畴和研究内容,在学科层面上存在其他学科无法解决或者解决好的科学问题,并从研究区域和研究对象的角度分析了沙漠生态学形成独立学科方向的必要性。沙漠生态学学科体系建设和基础理论丰富与完善,有利于指导干旱、半干旱区沙漠化的发生原因、过程及原理、沙漠化逆转过程的恢复机理的全面系统研究,为沙漠化综合治理措施与治理实践、沙漠自然资源利用与开发以及沙漠生态系统保护提供关键科技支撑,凸显了沙漠生态学的特色学科方向对区域荒漠化综合防治和“三北”防护林生态工程建设的重要理论和实践指导意义。 展开更多
关键词 沙漠生态学 概念 学科定位 区域特色 沙漠化治理
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荒漠化矿区土壤碳排放高光谱遥感反演
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作者 刘英 刘宇 +3 位作者 岳辉 毕银丽 彭苏萍 贾羽豪 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2024年第10期2840-2849,共10页
随着我国“碳达峰、碳中和”政策的提出,矿区碳排放成为关注焦点,然而目前缺少矿区土壤碳排放高光谱遥感探测的有效方法。基于矿区实测土壤样品,将6种光谱数学变换方法(R、■、Log(1/R)、1st、MSC、SNV)与光谱特征筛选方法(CC-SPA)相结... 随着我国“碳达峰、碳中和”政策的提出,矿区碳排放成为关注焦点,然而目前缺少矿区土壤碳排放高光谱遥感探测的有效方法。基于矿区实测土壤样品,将6种光谱数学变换方法(R、■、Log(1/R)、1st、MSC、SNV)与光谱特征筛选方法(CC-SPA)相结合,探究新疆红沙泉露天煤矿不同土地利用类型土壤碳排放的高光谱响应特征;结合土壤温度(ST)、土壤湿度(SM)及6种光谱指数(NDVI、RVI、NGLI、SMMI、SI-T、ATI),利用偏最小二乘(PLSR)、支持向量机(SVM)、随机森林(RF)、遗传优化神经网络(GA-BP)算法得到土壤碳排放最优遥感反演模型。主要结论如下:(1)自然条件下非采矿影响区土壤反射率明显高于采矿影响区,其中南线受煤炭开采影响最大,反射率最低,证明采矿活动对矿区土壤产生了影响;(2)光谱特征筛选方面,基于相关系数-连续投影算法(CC-SPA)提取的碳排放特征波段数远小于单一方法,且筛选结果呈现聚集式分布,主要集中于1600~2200 nm波长范围内,白天特征波段数远高于夜晚,相较于白天,夜晚特征波段具有明显向长波移动的特征。(3)添加基于反射率构建的光谱指数及ST、SM的反演模型估测土壤碳排放速率的精度明显提升,基于一阶微分变换(1st)的支持向量机模型(SVM)模型反演矿区综合土地利用类型土壤碳排放效果最好(验证集R2=0.813、RMSE=0.116);5种不同土地利用类型土壤碳排放最佳指数组合方式存在差异,引入不同的光谱指数对土壤碳排放速率的估测精度均有不同程度的提升(验证集R2均在0.8以上),其土壤碳排放最优反演模型均可较为准确地估算红沙泉矿区不同土地利用类型土壤的碳排放速率。本研究可为荒漠化矿区土壤碳排放遥感反演提供依据,定量识别不同土地利用类型下土壤的碳源汇效应,并实现了矿区碳排放的无损探测,为我国“30·60”双碳目标提供数据支撑。 展开更多
关键词 碳排放 高光谱 不同土地利用类型 昼夜 荒漠化矿区
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适宜高钙环境的桑种质资源筛选
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作者 范伟 孔秋月 +2 位作者 胡杰 刘洋 赵爱春 《西南大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第10期90-98,共9页
桑树是一种兼具经济效益和生态效益的树种,适宜在石漠化地区推广种植.高钙是石漠化地区土壤的重要特征之一,也是限制植物生长发育的主要因素之一.因此,了解我国大面积栽植的不同杂交桑品种的高钙耐受性,并筛选耐高钙胁迫的品种具有重要... 桑树是一种兼具经济效益和生态效益的树种,适宜在石漠化地区推广种植.高钙是石漠化地区土壤的重要特征之一,也是限制植物生长发育的主要因素之一.因此,了解我国大面积栽植的不同杂交桑品种的高钙耐受性,并筛选耐高钙胁迫的品种具有重要意义.以7个杂交桑品种幼苗为材料,研究不同桑树品种在高钙胁迫下的生理生化响应,并通过隶属函数法综合评价各品种的耐钙胁迫特性.结果表明:不同桑树品种在高钙胁迫下生长受到显著抑制,脯氨酸质量分数显著上升,而品种间抗氧化酶响应胁迫的模式存在差异.基于隶属函数值,聚类分析发现丰驰和桂桑优62为强高钙耐受品种,粤桑11和桂桑优12为中等高钙耐受品种,塘10×伦109、桂桑6和桂桑优2为高钙敏感品种. 展开更多
关键词 桑树 石漠化 高钙胁迫 品种筛选 隶属函数
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面向连接关键词可搜索加密的查询恢复攻击
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作者 杜瑞颖 沈蓓 +3 位作者 何琨 赵陈斌 王贝宁 陈晶 《通信学报》 EI CSCD 北大核心 2024年第8期125-135,共11页
为了恢复连接关键词可搜索加密方案中的用户查询,提出了2种针对连接查询可搜索加密方案的攻击方法,分别是交叉泄露攻击和频率匹配攻击。首先,从泄露中提取候选关键词集合;然后,分别利用关键词对结果模式泄露和查询频率信息进行过滤。结... 为了恢复连接关键词可搜索加密方案中的用户查询,提出了2种针对连接查询可搜索加密方案的攻击方法,分别是交叉泄露攻击和频率匹配攻击。首先,从泄露中提取候选关键词集合;然后,分别利用关键词对结果模式泄露和查询频率信息进行过滤。结果表明,在交叉泄露攻击中,当攻击者仅掌握10%的数据集时,若关键词在空间为100,查询恢复的准确率可高达90%,将关键词空间扩大至1000,攻击者依然能够恢复50%以上的查询;在频率匹配攻击中,即使攻击者仅已知不准确的频率分布信息,也至少可以准确恢复70%的查询。 展开更多
关键词 云存储 可搜索加密 连接关键词查询 查询恢复攻击
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基于生态系统脆弱性评价的典型岩溶区生态治理分区
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作者 胡兆鑫 罗为群 +2 位作者 蒋忠诚 吴泽燕 汤庆佳 《中国岩溶》 CAS CSCD 北大核心 2024年第3期661-671,703,共12页
文章以广西平果果化石漠化生态修复示范区为研究对象,基于“成因-结果”模型选取7个指标建立生态系统脆弱性评价指标体系,利用GIS技术和层次分析法进行生态系统脆弱性评价,通过单参数分析法计算各评价指标对生态系统脆弱性的贡献率,分... 文章以广西平果果化石漠化生态修复示范区为研究对象,基于“成因-结果”模型选取7个指标建立生态系统脆弱性评价指标体系,利用GIS技术和层次分析法进行生态系统脆弱性评价,通过单参数分析法计算各评价指标对生态系统脆弱性的贡献率,分析造成研究区生态系统脆弱性的主要影响因素。结果表明:研究区微度、轻度、中度、重度和极度脆弱生态系统脆弱性等级面积占比分别为36.43%、33.90%、18.91%、9.34%和1.43%,造成研究区生态系统轻度、中度脆弱的主要因素是岩性和土地利用方式,造成研究区生态系统重度、极度脆弱的主要因素是生态环境退化。依据评价结果,基于土地利用现状,结合坡度、地块面积等条件,划定生态治理分区并制订相应治理措施。其中,封山育林区应禁止一切人为破坏活动;人工造林区可在植被盖度较低的地块种植阳性树种,在植被群落高度较高、盖度适中的地块种植中性和阴性树种;林下种植区可引进赤苍藤、金银花等特色经济植物;草地改良区可引进桂牧一号、菊苣草、甜象草等优质牧草;园地改造区可在现有经果林下套种赤苍藤、金银花等矮杆经济作物;特色经济植物种植区可引进赤苍藤、树仔菜等常绿经济植物;退耕还林区因地制宜造林种草;矿山修复区采用多种技术手段复垦复绿;非治理区保持现状。 展开更多
关键词 岩溶 生态系统脆弱性评价 生态治理分区 果化示范区 环境退化
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云南省岩溶地区石漠化土地治理分区研究
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作者 安科 邓军 +5 位作者 彭正武 吴宁 任晓东 张如松 余正才 毛凯东 《林业调查规划》 2024年第3期58-63,共6页
根据云南省岩溶地区石漠化土地空间分布特征和各区域地质地貌、气候、水文、岩溶土壤和森林植被分布,结合碳酸盐岩的类型、岩性组合特征、不同岩溶地貌对区域环境和水土资源的制约、石漠化在不同地貌条件下的形成和发育特征,统筹考虑岩... 根据云南省岩溶地区石漠化土地空间分布特征和各区域地质地貌、气候、水文、岩溶土壤和森林植被分布,结合碳酸盐岩的类型、岩性组合特征、不同岩溶地貌对区域环境和水土资源的制约、石漠化在不同地貌条件下的形成和发育特征,统筹考虑岩溶生态系统的完整性、地理单元的连续性和经济社会发展的可持续性等因素,将全省88个岩溶监测县划分为6个治理区,并就各分区地理区位、地质地貌、成土母岩、水文、气候类型、森林植被类型分布以及各石漠化区不同类型岩溶土地面积占比等进行描述。 展开更多
关键词 岩溶地区 石漠化土地 治理分区 云南省
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高寒草地沙化过程土壤碳氮储量变化及其驱动机制
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作者 宗宁 缪雨珏 《生态学报》 CAS CSCD 北大核心 2024年第15期6642-6651,共10页
沙化问题是影响草原地区生产与牧民生活的重要环境问题。草原作为重要碳库和养分库,沙化过程可能会对其土壤碳、氮库产生重要影响。为探讨沙化过程对高寒草地土壤碳、氮储量的影响,采用空间序列代替时间演替的方法研究了藏北高原高寒草... 沙化问题是影响草原地区生产与牧民生活的重要环境问题。草原作为重要碳库和养分库,沙化过程可能会对其土壤碳、氮库产生重要影响。为探讨沙化过程对高寒草地土壤碳、氮储量的影响,采用空间序列代替时间演替的方法研究了藏北高原高寒草地沙化过程中驱动土壤碳、氮储量变化的因素。研究发现:(1)轻度、中度和重度沙化阶段土壤总碳、全氮储量无变化,而极重度沙化阶段碳氮流失严重(分别下降69%和55%,P<0.05)。(2)群落地上生物量随沙化程度加重逐渐降低,重度和极重度沙化草地根系生物量显著下降(分别下降47%和99%,P<0.05)。土壤容重、砾石含量随沙化程度加重呈逐渐增加趋势,而总碳、全氮含量和含水量逐渐下降,说明沙化过程导致土壤粗粒化和贫瘠化。(3)进一步分析发现,影响土壤总碳储量的因子中排前三位依次是土壤砾石含量、土壤含水量和植物地上生物量,影响土壤氮储量的因子依次是土壤砾石含量、含水量和土壤微生物丰度。综合这些研究结果,沙化过程植物群落生产力的改变对土壤碳、氮影响较小,主要受土壤砾石含量与含水量等因子驱动。沙化过程中土壤碳、氮储量存在转化阈值(重度到极重度沙化阶段),故潜在沙化高寒草地的早期防护有利于土壤碳汇的维持。 展开更多
关键词 沙化草地 西藏高原 理化性质 驱动因子
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提示对学习者自我生成教学过程和学习效果的作用
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作者 王福兴 黄宇 +2 位作者 张洋 祝婉玲 冷晓雪 《心理学报》 CSSCI CSCD 北大核心 2024年第4期469-481,共13页
研究主要探讨了自我生成教学中不同类型的提示对学习效果和学习感知的影响。实验1发现自我生成教学的学习效果好于重复学习。实验2对比了图片、文字、关键词三种提示和无提示的效果。结果发现图片和关键词提示具有更好的学习效果。实验... 研究主要探讨了自我生成教学中不同类型的提示对学习效果和学习感知的影响。实验1发现自我生成教学的学习效果好于重复学习。实验2对比了图片、文字、关键词三种提示和无提示的效果。结果发现图片和关键词提示具有更好的学习效果。实验3设置了关键词提示组、生成提示组和无提示组。结果发现关键词提示和生成提示的保持成绩好于无提示,生成提示的迁移成绩好于无提示。此外,关键词提示和生成提示可以促进学习者产生更多的概念单元。结论认为:(1)在自我生成教学时获得图片提示能促进知识保持,获得关键词提示能促进知识保持和迁移。(2)相比于被动获得提示,学习者主动生成提示更能促进知识迁移。(3)概念单元数量在提示影响学习效果中起中介作用。 展开更多
关键词 自我生成教学 提示 检索练习 关键词 生成性学习
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基于区块链高效安全的多部门铁路工程数据访问控制策略
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作者 郑云水 刘恒江 董昱 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2024年第6期2488-2498,共11页
针对铁路工程建设中各参建部门之间的数据资源,具有共享效率差、利用率低和安全程度不高的问题,提出一种基于区块链(Blockchain)铁路工程数据的共享及安全存储方案来弥补现有的铁路工程数据平台的不足。在工程建设平台中,引入了基于外... 针对铁路工程建设中各参建部门之间的数据资源,具有共享效率差、利用率低和安全程度不高的问题,提出一种基于区块链(Blockchain)铁路工程数据的共享及安全存储方案来弥补现有的铁路工程数据平台的不足。在工程建设平台中,引入了基于外包的属性加密技术(Outsourcing-Attribute Based Encryption technology, OABE)、区块链技术和星际文件系统(Interplanetary File System, IPFS)以及边缘节点(Edge Nodes, EN),并提出一种适用于铁路工程建设的多部门区块链与IPFS的协作网络。研究结果表明:当施工现场资源设备有限时,相比于较为传统基于云辅助的密文策略属性基加密技术(Ciphertext Policy Attribute Based Encryption, CP-ABE),通过将铁路工程数据外包给边缘节点,可以更好地为资源受限设备提供大量的计算,减轻设备的计算负担,确保了数据的安全性并且提高了设备的计算效率。而且将铁路工程数据存储在星际文件系统上,避免集中式的服务器机制在故障时造成数据的丢失和泄露。此外,通过使用区块链网络可以提高参建单位之间的数据资源共享效率,增强了数据的利用率,利用区块链的共识性来实现每个参建单位之间数据的一致性,确保了不同参建单位间的信任度。经过安全性证明,采用基于双线性迪菲赫尔曼指数假设(Decision q-Bilinear Diffie Hellman Exponent Assumption, q-BDHE)下具有不可区分性是安全的。实验结果表明,该策略在本地用户计算时间效率上与现有的带关键字搜索的外包属性基加密方案以及属性基加密的方案相比是最优的,可以很好地减轻现场设备的计算负担。 展开更多
关键词 铁路工程数据 区块链 关键字搜索 外包属性基加密 安全性
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