Over the past few decades, built-up land in China has increasingly expanded with rapid urbanization, industrialization and rural settlements construction. The expansions encroached upon a large amount of cropland, pla...Over the past few decades, built-up land in China has increasingly expanded with rapid urbanization, industrialization and rural settlements construction. The expansions encroached upon a large amount of cropland, placing great challenges on national food security. Although the impacts of urban expansion on cropland have been intensively illustrated, few attentions have been paid to differentiating the effects of growing urban areas, rural settlements, and industrial/transportation land. To fill this gap and offer comprehensive implications on framing policies for cropland protection, this study investigates and compares the spatio-temporal patterns of cropland conversion to urban areas, rural settlements, and industrial/transportation land from 1987 to 2010, based on land use maps interpreted from remote sensing imagery. Five indicators were developed to analyze the impacts of built-up land expansion on cropland in China. We find that 42,822 km2 of cropland were converted into built-up land in China, accounting for 43.8% of total cropland loss during 1987-2010. Urban growth showed a greater impact on cropland loss than the expansion of rural settlements and the expansion of industrial/transportation land after 2000. The contribution of rural settlement expansion decreased; however, rural settlement saw the highest percentage of traditional cropland loss which is generally in high quality. The contribution of industrial/transportation land expansion increased dramatically and was mainly distributed in major food production regions. These changes were closely related to the economic restructuring, urban-rural transformation and government policies in China. Future cropland conservation should focus on not only finding a reasonable urbanization mode, but also solving the ＂hollowing village＂ problem and balancing the industrial transformations.展开更多
Primula beesiana Forr.is an attractive wildflower endemically distributed in the wet habitats of subalpine/alpine regions of southwestern China.This study is an attempt to understand how this plant adapts to wet habit...Primula beesiana Forr.is an attractive wildflower endemically distributed in the wet habitats of subalpine/alpine regions of southwestern China.This study is an attempt to understand how this plant adapts to wet habitats and high altitudes.Specifically,we examined the effects of cold stratification,light,GA3,KNO3,and temperature on P.beesiana seed germination.KNO3 and GA3 increased germination percentage and germination rate compared to control treatments at 15/5 and 25/15℃.Untreated seeds germinated well(>80%)at higher temperatures(20,25 and 28℃),whereas at lower(5,10 and15℃)and extremely high temperatures(30 and 32℃)germination decreased significantly.However,after cold stratification(4-16 weeks),the germination percentage of P.beesiana seeds at low temperatures(5-15℃)and the germination rate at high temperatures(30℃)increased significantly,suggesting that P.beesiana has type 3 non-deep physiological dormancy.The base temperature and thermal time for germination decreased in seeds that were cold stratified for 16 weeks.Cold-stratified seeds incubated at fluctuating temperatures(especially at 15/5℃)had significantly high germination percentages and germination rates in light,but not in dark,compared to the corresponding constant temperature(10℃).Seeds had a strict light requirement at all temperatures,even after experiencing cold stratification;however,the combinations of cold stratification and fluctuating temperature increased germination when seeds were transferred from dark to light.Such dormancy/germination responses to light and temperature are likely mechanisms that ensure germination occurs only in spring and at/near the soil surface,thus avoiding seedling death by freezing,inundation and/or germination deep in the soil.展开更多
The interprovincial terrestrial physical geographical entities are the key areas of regional integrated management. In this paper, we analyzed the spatial patterns of the interprovincial terrestrial physical geographi...The interprovincial terrestrial physical geographical entities are the key areas of regional integrated management. In this paper, we analyzed the spatial patterns of the interprovincial terrestrial physical geographical names(ITPGN) from three aspects: numerical features, spatial variance and spatial agglomeration. The influencing factors of the distribution of ITPGN and the implications for the regional management were further discussed. GIS technology was used to visualize the distribution of ITPGN, analyze the spatial agglomeration and the influencing factors of ITPGN. A total of 11,325 ITPGN, including 4243 water ITPGN and 7082 terrain ITPGN, were extracted from the database of "China's Second National Survey of Geographical Names(2014–2018)", and the mountain geographical names were the largest type in ITPGN. Hunan Province had the largest number of the names in China, and Shanghai had the smallest number of the names. The spatial variance of the terrain ITPGN was larger than that of the water ITPGN, and the ITPGN showed a significant agglomeration phenomenon in the southern part of China. In addition, the relative elevation and the population had an impact on the distribution of the ITPGN. The largest number of the geographical names occurred in the regions where the relative elevation was between 1000–2000 meters, and where the population was between 40–50 million. Based on the analysis, it was suggested that the government should take the ITPGN as management units, optimize management strategies based on the characteristics of different types of ITPGN, strengthen the naming of unnamed interprovincial terrestrial physical geographical entities and balance the interests in the controversial ITPGN. This study demonstrated that GIS and spatial analysis techniques were useful for the research of ITPGN and the results could provide targeted management suggestions to realize coordinated development in the interprovincial regions.展开更多
Suffering from fragile environment, poor accessibility and infrastructure, as well as social,political and economic marginality, the interprovincial mountain geographical entities are difficult areas for the regional ...Suffering from fragile environment, poor accessibility and infrastructure, as well as social,political and economic marginality, the interprovincial mountain geographical entities are difficult areas for the regional governance in China.By analyzing the spatial patterns and the influencing factors of the interprovincial mountain geographical names(IMGNs), the goal of this research is to clarify the geographical features of IMGNs and offer alternatives for the management of interprovincial mountain regions in China. The spatial visualization,the analysis of spatial agglomeration and the influencing factors of IMGNs were all implemented under a geographical information system. Results showed that there were 6869 IMGNs in China according to the database of "China's Second National Survey of Geographical Names(2014-2018)",including 4209 mountain geographical names, 1684 mountain peak geographical names and 976 the other mountain geographical names. Hunan Province had the largest number of names while Shanghai had the smallest number of names. In addition, the spatial variance of the mountain peak names and the mountain names were larger than that of the other mountain geographical names, and the IMGNs showed a significant clustering phenomenon in the southern part of China. The relative elevation and the population had an impact on the distribution of the IMGNs. The largest number of the names occurred where the relative elevation was between 1000-2000 m and where the population was between 40-50 million. Density of unnamed interprovincial mountain geographical entities declined from west to east in China. The analysis of generic names of different types of IMGNs implied that the naming of IMGNs is inconsistent. Based on these analyses, it is suggested that the government should take the IMGNs as management units, strengthen the naming of unnamed interprovincial mountain geographical entities, standardize the generic names of IMGNs and identify areas of poverty based on the survey of IMGNs.展开更多
An algorithm was developed for identifying and tracking a magnetic bright point, or bright point （BP） for short, observed in both the photosphere （G-band） and chromosphere （Ca II H）, as well as for pairing a pho...An algorithm was developed for identifying and tracking a magnetic bright point, or bright point （BP） for short, observed in both the photosphere （G-band） and chromosphere （Ca II H）, as well as for pairing a photospheric BP （PBP） with its conjugate chromospheric BP （CBP）. Two sets of data observed by Hinode/SOT in the quiet Sun near the disk center were analyzed. About 278 PBP-CBP pairs were identified and tracked. Lifetimes of both the PBPs and CBPs follow an exponential distribution with average lifetimes of 174 s and 163 s, respectively. We found that the differences in appearance time, in disappearance time and in lifetime of the two kinds of BPs all follow Gaussian distributions,which may indicate that the mechanisms of PBP and CBP formation/disintegration are different. However, the lifetimes of PBPs and CBPs are positively correlated with one another, with a correlation coefficient of 0.8. Furthermore, we calculated the horizontal displacement between the PBP and its conjugate CBP, which follows a Gaussian function with an average and standard deviation of （67.7 ± 38.5）km. We also calculated the amplitude of the flux tube shape change which might be caused by MHD waves propagating along the flux tube, and found that it follows an exponential distribution very well.展开更多
The quality of the data for statistical methods plays an important role in landslide susceptibility mapping.How different data types influence the performance of landslide susceptibility maps is worth studying.The goa...The quality of the data for statistical methods plays an important role in landslide susceptibility mapping.How different data types influence the performance of landslide susceptibility maps is worth studying.The goal of this study was to explore the effects of different data types namely,presence-only(PO),presence-absence(PA),and pseudo-absence(PAs) data,on the predictive capability of landslide susceptibility mapping.This was completed by conducting a case study in the landslide-prone Honghe County in the Yunnan Province of China.A total of 428 landslide PO data points were selected.An equivalent number of nonlandslide locations were generated as PA data by random sampling,and 10,000 sites were uniformly selected at random from each region as PAs data.Three landslide susceptibility models,namely the information value model(IVM),logistic regression(LR) model,and maximum entropy(MaxEnt) model,corresponding to the three data types were investigated.Additionally,the area under the receiver operating characteristic curves(ROC-AUC),seven statistical indices(i.e.accuracy,sensibility,falsepositive rate,specificity,precision,Kappa,and Fmeasure),and a landslide density analysis were used to evaluate model performance regarding landslide susceptibility mapping.Our results indicated that the MaxEnt model using PAs data performed the best and had the highest fitness with the highest ROC-AUC values and statistical indices,followed by the IVM model with only landslide data(PO),and the LR model using PA data.Using PAs data avoided the inherent over-predictive shortcomings of PO data by limiting the predicted area of high-landslide susceptibility.Additionally,the random sampling design of landslide PA data increased the uncertainty of landslide susceptibility mapping and influenced the performance of the model.Therefore,our results suggested that the PAs data sampling provided a useful data type in the absence of high-quality data.Finally,we summarized the principles,advantages,and disadvantages of the three data types to assist with model optimization and the improvement of predicted performance and fitness.展开更多
Tourism resources that span provincial boundaries in China play a pivotal role in regional development,yet effective governance poses persistent challenges.This study addresses this issue by constructing a comprehensi...Tourism resources that span provincial boundaries in China play a pivotal role in regional development,yet effective governance poses persistent challenges.This study addresses this issue by constructing a comprehensive database of transboundary natural tourism resources(TNTR)through amalgamation of diverse data sources.Utilizing the Getis-Ord Gi^(*),kernel density estimation,and geographical detectors,we scrutinize the spatial patterns of TNTR,focusing on both named and unnamed entities,while exploring the influencing factors.Our findings reveal 7883 identified TNTR in China,with mountain tourism resources emerging as the predominant type.Among provinces,Hunan boasts the highest count,while Shanghai exhibits the lowest.Southern China demonstrates a pronounced clustering trend in TNTR distribution,with the spatial arrangement of biological landscapes appearing more random compared to geological and water landscapes.Western China,characterized by intricate terrain,exhibits fewer TNTR,concurrently unveiling a significant presence of unnamed natural tourism resources.Crucially,administrative segmentation influences TNTR development,generating disparities in regional goals,developmental stages and intensities,and management approaches.In response to these variations,we advocate for strengthening the naming of the unnamed transboundary tourism resources,constructing a geographic database of TNTR for government and establishing a collaborative management mechanism based on TNTR database.Our research contributes to elucidating the intricate landscape of TNTR,offering insights for tailored governance strategies in the realm of cross-provincial tourism resource management.展开更多
A solar radio burst was observed in a coronal mass ejection/flare event by the Solar Broadband Radio Spectrometer at the Huairou Solar Observing Station on2004 December 1. The data exhibited various patterns of plasma...A solar radio burst was observed in a coronal mass ejection/flare event by the Solar Broadband Radio Spectrometer at the Huairou Solar Observing Station on2004 December 1. The data exhibited various patterns of plasma motions, suggestive of the interaction between sunward moving plasmoids and the flare loop system during the impulsive phase of the event. In addition to the radio data, the associated whitelight, Hα, extreme ultraviolet light, and soft and hard X-rays were also studied.展开更多
The analysis of the spatial distribution of tourism resources and the identification of its influencing factors are crucial for supporting the sustainable development of regional tourism.This study established a compr...The analysis of the spatial distribution of tourism resources and the identification of its influencing factors are crucial for supporting the sustainable development of regional tourism.This study established a comprehensive database of tourism resources in Ningxia Hui Autonomous Region(Ningxia)through a combination of literature review and field research.It examined the quantitative,qualitative,and categorical characteristics of tourism resources in Ningxia,and determined the spatial patterns based on kernel density and spatial association analysis.This study also comprehensively evaluated the societal,economic,and environmental factors influencing the spatial distribution of tourism resources in the entire region by employing the geographical detector model to quantify the influence of each factor.The following results were obtained.(1)There were 29218 individual tourism resources in Ningxia,comprising eight main types,23 subtypes,and 105 fundamental types,and they exhibit a hierarchical pyramidal structure.(2)The tourism resources in Ningxia displayed characteristics of“widespread regional dispersion and limited regional agglomeration”.The spatial distribution of tourism resources was highly imbalanced,and most types of tourism resources exhibit strong positive spatial correlation.(3)The altitude,annual precipitation,population density,distance from urban centers,urbanization rate,and per capita GDP were identified as significant factors influencing the spatial distribution of tourism resources in Ningxia.Based on the results,we recommend that the government should formulate tourism development policies in Ningxia based on local conditions to effectively address the spatial imbalances,enhance the sustainability of tourism development,and continue to promote high-quality tourism development in Ningxia.展开更多
Substantial evidence suggests that the utilization of green spaces may have a significant impact on the physical,psychological,and social health and well-being of children.Therefore,the decline in green space usage am...Substantial evidence suggests that the utilization of green spaces may have a significant impact on the physical,psychological,and social health and well-being of children.Therefore,the decline in green space usage among contemporary children indicates a need to explore the factors that affect the frequency of park usage.In this study,a multi-level regression model was developed and used to identify the factors influencing children’s use of green parks.Six urban parks in the central city of Shanghai,China,were taken as cases,and the influencing factors of 317 children aged 6-9 years were examined using the two levels of parents and parks.Parental factors included the parents’perception of benefits obtained from park activities,their own childhood outdoor experience,their working hours,and their worries about the potential for accidents.The natural environment scoring tool was adopted for evaluating park features.According to the results,for children aged 6-9 years,parental factors play a decisive role in promoting or preventing their connection with urban parks.The urban park factors,especially their usability,are also important factors promoting children’s park use.Therefore,to improve the interaction between children and urban parks,various methods and approaches can be adopted such as education of the parents,green space management,urban planning,and social marketing.展开更多
The values of farmland ecosystem services are composed of several components: provisioning service value, regulating service value, supporting service value and cultural service value, so it is important to make a ful...The values of farmland ecosystem services are composed of several components: provisioning service value, regulating service value, supporting service value and cultural service value, so it is important to make a full assessment of the values of farmland ecosystem services for agriculture and farmland protection. Here, we assessed the values of farmland ecosystem services in Qingdao City in 1997, 2002, 2007, 2012 and 2017 by using various methods(market value method, carbon tax method, afforestation cost method, substitute cost method, equivalent factor method, etc.) based on establishing an assessment index system for the farmland ecosystem services value. The results show that the total yearly value of farmland ecosystem services increased from 499.74× 10~8 Yuan to 681.74× 10~8 Yuan in the period of 1997-2017, and the yearly value of farmland ecosystem services per hectare increased from 6.57× 10~4 Yuan to 9.73× 10~4 Yuan. The product provisioning service, carbon fixation service and oxygen release service, as well as the soil conservation service, are the main farmland ecosystem services, and the proportions of these four ecosystem service values to the total value of farmland ecosystem services in Qingdao City were large and kept increasing. Some countermeasures are put forward to adequately use the indirect service value of the farmland ecosystem and provide improved well-being for humans, such as protecting and wisely using farmland, developing agriculture that is rooted in local conditions, promoting agricultural production efficiency, speeding up construction of modern agriculture gardens, deepening the supply-side structural reform of agriculture, developing agricultural eco-tourism, etc.展开更多
Encrypted traffic classification has become a hot issue in network security research.The class imbalance problem of traffic samples often causes the deterioration of Machine Learning based classifier performance.Altho...Encrypted traffic classification has become a hot issue in network security research.The class imbalance problem of traffic samples often causes the deterioration of Machine Learning based classifier performance.Although the Generative Adversarial Network(GAN)method can generate new samples by learning the feature distribution of the original samples,it is confronted with the problems of unstable training andmode collapse.To this end,a novel data augmenting approach called Graph CWGAN-GP is proposed in this paper.The traffic data is first converted into grayscale images as the input for the proposed model.Then,the minority class data is augmented with our proposed model,which is built by introducing conditional constraints and a new distance metric in typical GAN.Finally,the classical deep learning model is adopted as a classifier to classify datasets augmented by the Condition GAN(CGAN),Wasserstein GAN-Gradient Penalty(WGAN-GP)and Graph CWGAN-GP,respectively.Compared with the state-of-the-art GAN methods,the Graph CWGAN-GP cannot only control the modes of the data to be generated,but also overcome the problem of unstable training and generate more realistic and diverse samples.The experimental results show that the classification precision,recall and F1-Score of theminority class in the balanced dataset augmented in this paper have improved by more than 2.37%,3.39% and 4.57%,respectively.展开更多
0 INTRODUCTION.Fire flooding is a thermal oil recovery technique in which heating promotes high-temperature oxidation reactions between crude oil and injected air,causing heat and gas release as well as the migration ...0 INTRODUCTION.Fire flooding is a thermal oil recovery technique in which heating promotes high-temperature oxidation reactions between crude oil and injected air,causing heat and gas release as well as the migration of unburnt crude oil toward production wells.The method is advantageous due to its high recovery rate,low cost,and wide applicability as an effective replacement technique for heavy-oil reservoirs,and has been successfully practiced at the Liaohe Oilfield of China(Zhang et al.,2020;Aleksandrov and Hascakir,2015;Elbaz et al.,2015;Hascakir et al.,2011;Huang et al.,2010).展开更多
An increasing number of studies have shown that many alpine lakes have experienced rapid ecosystem transformations over the past^200 years[1–3].However,the mechanisms responsible for triggering these changes are ofte...An increasing number of studies have shown that many alpine lakes have experienced rapid ecosystem transformations over the past^200 years[1–3].However,the mechanisms responsible for triggering these changes are often ambiguous in paleolimnological records and hence they are often debated.A major reason for this is that lake ecosystems are under increasing pressure from both anthropogenic activities and climate change.Possible means of distinguishing the effects of different regional drivers of lake ecosystem changes include the study of paleolimnological contexts which predate human activity,or the study of alpine lakes which are still largely unaffected by local human activity.展开更多
基金National Major Science and Technology Program for Water Pollution Control and Treatment,No.2017ZX07101001
文摘Over the past few decades, built-up land in China has increasingly expanded with rapid urbanization, industrialization and rural settlements construction. The expansions encroached upon a large amount of cropland, placing great challenges on national food security. Although the impacts of urban expansion on cropland have been intensively illustrated, few attentions have been paid to differentiating the effects of growing urban areas, rural settlements, and industrial/transportation land. To fill this gap and offer comprehensive implications on framing policies for cropland protection, this study investigates and compares the spatio-temporal patterns of cropland conversion to urban areas, rural settlements, and industrial/transportation land from 1987 to 2010, based on land use maps interpreted from remote sensing imagery. Five indicators were developed to analyze the impacts of built-up land expansion on cropland in China. We find that 42,822 km2 of cropland were converted into built-up land in China, accounting for 43.8% of total cropland loss during 1987-2010. Urban growth showed a greater impact on cropland loss than the expansion of rural settlements and the expansion of industrial/transportation land after 2000. The contribution of rural settlement expansion decreased; however, rural settlement saw the highest percentage of traditional cropland loss which is generally in high quality. The contribution of industrial/transportation land expansion increased dramatically and was mainly distributed in major food production regions. These changes were closely related to the economic restructuring, urban-rural transformation and government policies in China. Future cropland conservation should focus on not only finding a reasonable urbanization mode, but also solving the ＂hollowing village＂ problem and balancing the industrial transformations.
基金the National Key R&D Program of China(2017YF0505200 to H.Sun)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA 20050203 to H.Sun)+1 种基金the Key Program of the National Natural Science Foundation of China(U1802232 to H.Sun)National Natural Science Foundation of China(grant 31700284 to D.L.Peng,31670206 to Z.M.Li and 31900185 to L.E.Yang)。
文摘Primula beesiana Forr.is an attractive wildflower endemically distributed in the wet habitats of subalpine/alpine regions of southwestern China.This study is an attempt to understand how this plant adapts to wet habitats and high altitudes.Specifically,we examined the effects of cold stratification,light,GA3,KNO3,and temperature on P.beesiana seed germination.KNO3 and GA3 increased germination percentage and germination rate compared to control treatments at 15/5 and 25/15℃.Untreated seeds germinated well(>80%)at higher temperatures(20,25 and 28℃),whereas at lower(5,10 and15℃)and extremely high temperatures(30 and 32℃)germination decreased significantly.However,after cold stratification(4-16 weeks),the germination percentage of P.beesiana seeds at low temperatures(5-15℃)and the germination rate at high temperatures(30℃)increased significantly,suggesting that P.beesiana has type 3 non-deep physiological dormancy.The base temperature and thermal time for germination decreased in seeds that were cold stratified for 16 weeks.Cold-stratified seeds incubated at fluctuating temperatures(especially at 15/5℃)had significantly high germination percentages and germination rates in light,but not in dark,compared to the corresponding constant temperature(10℃).Seeds had a strict light requirement at all temperatures,even after experiencing cold stratification;however,the combinations of cold stratification and fluctuating temperature increased germination when seeds were transferred from dark to light.Such dormancy/germination responses to light and temperature are likely mechanisms that ensure germination occurs only in spring and at/near the soil surface,thus avoiding seedling death by freezing,inundation and/or germination deep in the soil.
基金Atlas of the People’s Republic of China(New Century Edition)Research,No.2013FY112800
文摘The interprovincial terrestrial physical geographical entities are the key areas of regional integrated management. In this paper, we analyzed the spatial patterns of the interprovincial terrestrial physical geographical names(ITPGN) from three aspects: numerical features, spatial variance and spatial agglomeration. The influencing factors of the distribution of ITPGN and the implications for the regional management were further discussed. GIS technology was used to visualize the distribution of ITPGN, analyze the spatial agglomeration and the influencing factors of ITPGN. A total of 11,325 ITPGN, including 4243 water ITPGN and 7082 terrain ITPGN, were extracted from the database of "China's Second National Survey of Geographical Names(2014–2018)", and the mountain geographical names were the largest type in ITPGN. Hunan Province had the largest number of the names in China, and Shanghai had the smallest number of the names. The spatial variance of the terrain ITPGN was larger than that of the water ITPGN, and the ITPGN showed a significant agglomeration phenomenon in the southern part of China. In addition, the relative elevation and the population had an impact on the distribution of the ITPGN. The largest number of the geographical names occurred in the regions where the relative elevation was between 1000–2000 meters, and where the population was between 40–50 million. Based on the analysis, it was suggested that the government should take the ITPGN as management units, optimize management strategies based on the characteristics of different types of ITPGN, strengthen the naming of unnamed interprovincial terrestrial physical geographical entities and balance the interests in the controversial ITPGN. This study demonstrated that GIS and spatial analysis techniques were useful for the research of ITPGN and the results could provide targeted management suggestions to realize coordinated development in the interprovincial regions.
基金supported by the Project of "Atlas of the People's Republic of China (New Century Edition)”funded by Ministry of Science and Technology, China (No. 2013FY112800)
文摘Suffering from fragile environment, poor accessibility and infrastructure, as well as social,political and economic marginality, the interprovincial mountain geographical entities are difficult areas for the regional governance in China.By analyzing the spatial patterns and the influencing factors of the interprovincial mountain geographical names(IMGNs), the goal of this research is to clarify the geographical features of IMGNs and offer alternatives for the management of interprovincial mountain regions in China. The spatial visualization,the analysis of spatial agglomeration and the influencing factors of IMGNs were all implemented under a geographical information system. Results showed that there were 6869 IMGNs in China according to the database of "China's Second National Survey of Geographical Names(2014-2018)",including 4209 mountain geographical names, 1684 mountain peak geographical names and 976 the other mountain geographical names. Hunan Province had the largest number of names while Shanghai had the smallest number of names. In addition, the spatial variance of the mountain peak names and the mountain names were larger than that of the other mountain geographical names, and the IMGNs showed a significant clustering phenomenon in the southern part of China. The relative elevation and the population had an impact on the distribution of the IMGNs. The largest number of the names occurred where the relative elevation was between 1000-2000 m and where the population was between 40-50 million. Density of unnamed interprovincial mountain geographical entities declined from west to east in China. The analysis of generic names of different types of IMGNs implied that the naming of IMGNs is inconsistent. Based on these analyses, it is suggested that the government should take the IMGNs as management units, strengthen the naming of unnamed interprovincial mountain geographical entities, standardize the generic names of IMGNs and identify areas of poverty based on the survey of IMGNs.
基金supported by the CAS grants(XDA17010507,XDA15010900 and QYZDJ-SSWSLH012)the NationalBasic Research Program of China(973 Program,2013CBA01503)+1 种基金the National Natural Science Foundation of China(Grant Nos.U1631130,11333007 and 11763004)supported by a grant associated with the Project of the Group for Innovation of Yunnan Province
文摘An algorithm was developed for identifying and tracking a magnetic bright point, or bright point （BP） for short, observed in both the photosphere （G-band） and chromosphere （Ca II H）, as well as for pairing a photospheric BP （PBP） with its conjugate chromospheric BP （CBP）. Two sets of data observed by Hinode/SOT in the quiet Sun near the disk center were analyzed. About 278 PBP-CBP pairs were identified and tracked. Lifetimes of both the PBPs and CBPs follow an exponential distribution with average lifetimes of 174 s and 163 s, respectively. We found that the differences in appearance time, in disappearance time and in lifetime of the two kinds of BPs all follow Gaussian distributions,which may indicate that the mechanisms of PBP and CBP formation/disintegration are different. However, the lifetimes of PBPs and CBPs are positively correlated with one another, with a correlation coefficient of 0.8. Furthermore, we calculated the horizontal displacement between the PBP and its conjugate CBP, which follows a Gaussian function with an average and standard deviation of （67.7 ± 38.5）km. We also calculated the amplitude of the flux tube shape change which might be caused by MHD waves propagating along the flux tube, and found that it follows an exponential distribution very well.
基金supported by the Multigovernment International Science and Technology Innovation Cooperation Key Project of National Key Research and Development Program of China for the ‘Environmental monitoring and assessment of LULC change impact on ecological security using geospatial technologies’ (Grant No. 2018YFE0184300)National Natural Science Foundation of China (Grant Nos. 41271203, 41761115)the Program for Innovative Research Team (in Science and Technology) in the University of Yunnan Province, IRTSTYN。
文摘The quality of the data for statistical methods plays an important role in landslide susceptibility mapping.How different data types influence the performance of landslide susceptibility maps is worth studying.The goal of this study was to explore the effects of different data types namely,presence-only(PO),presence-absence(PA),and pseudo-absence(PAs) data,on the predictive capability of landslide susceptibility mapping.This was completed by conducting a case study in the landslide-prone Honghe County in the Yunnan Province of China.A total of 428 landslide PO data points were selected.An equivalent number of nonlandslide locations were generated as PA data by random sampling,and 10,000 sites were uniformly selected at random from each region as PAs data.Three landslide susceptibility models,namely the information value model(IVM),logistic regression(LR) model,and maximum entropy(MaxEnt) model,corresponding to the three data types were investigated.Additionally,the area under the receiver operating characteristic curves(ROC-AUC),seven statistical indices(i.e.accuracy,sensibility,falsepositive rate,specificity,precision,Kappa,and Fmeasure),and a landslide density analysis were used to evaluate model performance regarding landslide susceptibility mapping.Our results indicated that the MaxEnt model using PAs data performed the best and had the highest fitness with the highest ROC-AUC values and statistical indices,followed by the IVM model with only landslide data(PO),and the LR model using PA data.Using PAs data avoided the inherent over-predictive shortcomings of PO data by limiting the predicted area of high-landslide susceptibility.Additionally,the random sampling design of landslide PA data increased the uncertainty of landslide susceptibility mapping and influenced the performance of the model.Therefore,our results suggested that the PAs data sampling provided a useful data type in the absence of high-quality data.Finally,we summarized the principles,advantages,and disadvantages of the three data types to assist with model optimization and the improvement of predicted performance and fitness.
基金funded by the by the Youth Program of the National Natural Science Foundation of China(Grants No.42001243,and 42201311)the Humanities and Social Science Project of the Ministry of Education,China(Grants No.20YJC630212,and 22YJCZH071)+1 种基金the Youth Program of the Natural Science Foundation of Shandong Province,China(Grants No.ZR2020QD008)Frontier Science Research Support Program,Management College,OUC(Grants No.MCQYZD2305,and MCQYYB2309).
文摘Tourism resources that span provincial boundaries in China play a pivotal role in regional development,yet effective governance poses persistent challenges.This study addresses this issue by constructing a comprehensive database of transboundary natural tourism resources(TNTR)through amalgamation of diverse data sources.Utilizing the Getis-Ord Gi^(*),kernel density estimation,and geographical detectors,we scrutinize the spatial patterns of TNTR,focusing on both named and unnamed entities,while exploring the influencing factors.Our findings reveal 7883 identified TNTR in China,with mountain tourism resources emerging as the predominant type.Among provinces,Hunan boasts the highest count,while Shanghai exhibits the lowest.Southern China demonstrates a pronounced clustering trend in TNTR distribution,with the spatial arrangement of biological landscapes appearing more random compared to geological and water landscapes.Western China,characterized by intricate terrain,exhibits fewer TNTR,concurrently unveiling a significant presence of unnamed natural tourism resources.Crucially,administrative segmentation influences TNTR development,generating disparities in regional goals,developmental stages and intensities,and management approaches.In response to these variations,we advocate for strengthening the naming of the unnamed transboundary tourism resources,constructing a geographic database of TNTR for government and establishing a collaborative management mechanism based on TNTR database.Our research contributes to elucidating the intricate landscape of TNTR,offering insights for tailored governance strategies in the realm of cross-provincial tourism resource management.
基金Supported by the National Natural Science Foundation of China
文摘A solar radio burst was observed in a coronal mass ejection/flare event by the Solar Broadband Radio Spectrometer at the Huairou Solar Observing Station on2004 December 1. The data exhibited various patterns of plasma motions, suggestive of the interaction between sunward moving plasmoids and the flare loop system during the impulsive phase of the event. In addition to the radio data, the associated whitelight, Hα, extreme ultraviolet light, and soft and hard X-rays were also studied.
基金The Natural Science Foundation of Shandong Province(ZR2020QD008,ZR2022QD132)The Fundamental Research Funds for the CentralUniversities(202213002)The Rural Revitalization Project of Ocean University of China(ZX2024007).
文摘The analysis of the spatial distribution of tourism resources and the identification of its influencing factors are crucial for supporting the sustainable development of regional tourism.This study established a comprehensive database of tourism resources in Ningxia Hui Autonomous Region(Ningxia)through a combination of literature review and field research.It examined the quantitative,qualitative,and categorical characteristics of tourism resources in Ningxia,and determined the spatial patterns based on kernel density and spatial association analysis.This study also comprehensively evaluated the societal,economic,and environmental factors influencing the spatial distribution of tourism resources in the entire region by employing the geographical detector model to quantify the influence of each factor.The following results were obtained.(1)There were 29218 individual tourism resources in Ningxia,comprising eight main types,23 subtypes,and 105 fundamental types,and they exhibit a hierarchical pyramidal structure.(2)The tourism resources in Ningxia displayed characteristics of“widespread regional dispersion and limited regional agglomeration”.The spatial distribution of tourism resources was highly imbalanced,and most types of tourism resources exhibit strong positive spatial correlation.(3)The altitude,annual precipitation,population density,distance from urban centers,urbanization rate,and per capita GDP were identified as significant factors influencing the spatial distribution of tourism resources in Ningxia.Based on the results,we recommend that the government should formulate tourism development policies in Ningxia based on local conditions to effectively address the spatial imbalances,enhance the sustainability of tourism development,and continue to promote high-quality tourism development in Ningxia.
基金The National Natural Science Foundation of China(42171223)。
文摘Substantial evidence suggests that the utilization of green spaces may have a significant impact on the physical,psychological,and social health and well-being of children.Therefore,the decline in green space usage among contemporary children indicates a need to explore the factors that affect the frequency of park usage.In this study,a multi-level regression model was developed and used to identify the factors influencing children’s use of green parks.Six urban parks in the central city of Shanghai,China,were taken as cases,and the influencing factors of 317 children aged 6-9 years were examined using the two levels of parents and parks.Parental factors included the parents’perception of benefits obtained from park activities,their own childhood outdoor experience,their working hours,and their worries about the potential for accidents.The natural environment scoring tool was adopted for evaluating park features.According to the results,for children aged 6-9 years,parental factors play a decisive role in promoting or preventing their connection with urban parks.The urban park factors,especially their usability,are also important factors promoting children’s park use.Therefore,to improve the interaction between children and urban parks,various methods and approaches can be adopted such as education of the parents,green space management,urban planning,and social marketing.
基金The National Key Research and Development Plan of China (2016YFC0503503)The Natural Science Foundation of Shandong Province,China (ZR2016DM11)。
文摘The values of farmland ecosystem services are composed of several components: provisioning service value, regulating service value, supporting service value and cultural service value, so it is important to make a full assessment of the values of farmland ecosystem services for agriculture and farmland protection. Here, we assessed the values of farmland ecosystem services in Qingdao City in 1997, 2002, 2007, 2012 and 2017 by using various methods(market value method, carbon tax method, afforestation cost method, substitute cost method, equivalent factor method, etc.) based on establishing an assessment index system for the farmland ecosystem services value. The results show that the total yearly value of farmland ecosystem services increased from 499.74× 10~8 Yuan to 681.74× 10~8 Yuan in the period of 1997-2017, and the yearly value of farmland ecosystem services per hectare increased from 6.57× 10~4 Yuan to 9.73× 10~4 Yuan. The product provisioning service, carbon fixation service and oxygen release service, as well as the soil conservation service, are the main farmland ecosystem services, and the proportions of these four ecosystem service values to the total value of farmland ecosystem services in Qingdao City were large and kept increasing. Some countermeasures are put forward to adequately use the indirect service value of the farmland ecosystem and provide improved well-being for humans, such as protecting and wisely using farmland, developing agriculture that is rooted in local conditions, promoting agricultural production efficiency, speeding up construction of modern agriculture gardens, deepening the supply-side structural reform of agriculture, developing agricultural eco-tourism, etc.
基金supported by the National Natural Science Foundation of China (Grants Nos.61931004,62072250)the Talent Launch Fund of Nanjing University of Information Science and Technology (2020r061).
文摘Encrypted traffic classification has become a hot issue in network security research.The class imbalance problem of traffic samples often causes the deterioration of Machine Learning based classifier performance.Although the Generative Adversarial Network(GAN)method can generate new samples by learning the feature distribution of the original samples,it is confronted with the problems of unstable training andmode collapse.To this end,a novel data augmenting approach called Graph CWGAN-GP is proposed in this paper.The traffic data is first converted into grayscale images as the input for the proposed model.Then,the minority class data is augmented with our proposed model,which is built by introducing conditional constraints and a new distance metric in typical GAN.Finally,the classical deep learning model is adopted as a classifier to classify datasets augmented by the Condition GAN(CGAN),Wasserstein GAN-Gradient Penalty(WGAN-GP)and Graph CWGAN-GP,respectively.Compared with the state-of-the-art GAN methods,the Graph CWGAN-GP cannot only control the modes of the data to be generated,but also overcome the problem of unstable training and generate more realistic and diverse samples.The experimental results show that the classification precision,recall and F1-Score of theminority class in the balanced dataset augmented in this paper have improved by more than 2.37%,3.39% and 4.57%,respectively.
基金fund by the National Natural Science Foundation of China(No.42372263)the Open Research Project from the State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(No.GPMR202318).
文摘0 INTRODUCTION.Fire flooding is a thermal oil recovery technique in which heating promotes high-temperature oxidation reactions between crude oil and injected air,causing heat and gas release as well as the migration of unburnt crude oil toward production wells.The method is advantageous due to its high recovery rate,low cost,and wide applicability as an effective replacement technique for heavy-oil reservoirs,and has been successfully practiced at the Liaohe Oilfield of China(Zhang et al.,2020;Aleksandrov and Hascakir,2015;Elbaz et al.,2015;Hascakir et al.,2011;Huang et al.,2010).
基金supported by the National Natural Science Foundation of China (41790421, 41722105).
文摘An increasing number of studies have shown that many alpine lakes have experienced rapid ecosystem transformations over the past^200 years[1–3].However,the mechanisms responsible for triggering these changes are often ambiguous in paleolimnological records and hence they are often debated.A major reason for this is that lake ecosystems are under increasing pressure from both anthropogenic activities and climate change.Possible means of distinguishing the effects of different regional drivers of lake ecosystem changes include the study of paleolimnological contexts which predate human activity,or the study of alpine lakes which are still largely unaffected by local human activity.
