The quantum effect of nano-crystals is an important factor to improve nonlinear optical performance of nanocrystal embedded glasses, while controlling the size distribution and content of nano-crystals in the glass ac...The quantum effect of nano-crystals is an important factor to improve nonlinear optical performance of nanocrystal embedded glasses, while controlling the size distribution and content of nano-crystals in the glass accurately is a key to obtain good quality. The auxiliary direct current electric field, accompanied with heat treatment, was applied on AgCI containing niobic tellurite glass sheet. The nucleation and crystallization of the glass were well controlled under auxiliary electric field. It was found that the average size of AgCI nano-crystal particles in the glass is smaller than that under single heat treatment, and the content of nano- crystals is higher. Therefore the third-order nonlinear optical performance of the glass was increased a lot. The local-area distributed AgCl nano-crystal particles can also be embedded into a glass sheet by using locally applied electric field.展开更多
In order to maintain the optimal operating temperature of the battery surface and meet the demand for thermal storage technology,battery thermal management system based on phase change materials has attracted increasi...In order to maintain the optimal operating temperature of the battery surface and meet the demand for thermal storage technology,battery thermal management system based on phase change materials has attracted increasing interest.In this work,a kind of core-shell structured microcapsule was synthesized by an in-situ polymerization,where paraffin was used as the core,while methanol was applied to mod-ify the melamine-formaldehyde shell to reduce toxicity and improve thermal stability.Moreover,three different types of heat conductive fillers with the same content of 10 wt.%,i.e.,nano-Al_(2)O_(3),nano-ZnO and carbon nanotubes were added,generating composites.The microcapsules were uniform,and were not affected by the thermal fillers,which were evenly dispersed around.The composite sample with carbon nanotubes(10 wt.%)showed the highest thermal conductivity of 0.50 W/(m K)and latent heat of 139.64 J/g.Furthermore,according to the leakage testing and battery charge/discharge experiments,compared with Al_(2)O_(3)and ZnO,the addition of carbon nanotubes remarkably enhances the heat storage ability as latent heat from 126.98 J/g for the prepared sample with Al_(2)O_(3)and 125.86 J/g for the one with ZnO,then to 139.64 J/g,as well as dissipation performance as a cooling effect by decreasing the sur-face temperature of battery from 2%to 12%of microcapsule,composite sample with carbon nanotubes presents a broad application prospect in battery thermal management system and energy storage field.展开更多
Aims As a unique geographical unit of the earth,the tibetan Plateau is extensively covered by various Stipa communities.However,their vegetation features have not been reported systematically till now,especially in so...Aims As a unique geographical unit of the earth,the tibetan Plateau is extensively covered by various Stipa communities.However,their vegetation features have not been reported systematically till now,especially in some scantily explored regions.In this study,we endeavor to reveal the community types,quantitative charac-teristics and climatic distribution patterns of Stipa steppes in these areas based on primary relevés obtained from fieldwork.Methods We collected a total of 223 plots in 79 study sites in the Changthang Plateau and the Yarlung Zangbo Valley,ranging from 79°E to 91°E.the categories of Stipa formations were identified according to the classification scheme in Vegetation of China and then verified by Nonmetric Multidimensional Scaling.We performed detrended correspondence analysis and detrended canonical correspondence analysis to hunt for the alteration of Stipa communities along the precipitation gradient.Quantitative characteristics including species richness,coverage,biomass as well as importance values(IV)of dominant species were calcu-lated and visualized,respectively.Important Findings Stipa steppes in scantily explored regions of the tibetan Plateau are classified into 11 formations but major formations are rather limited in number.Formation(form.)Stipa purpurea is the most widespread Stipa assemblages not only in scantily explored regions but also across the whole tibetan Plateau.the characteristics of Stipa com-munities,including coverage,species richness,productivity and IV of dominant species,demonstrate the features of typical alpine steppes on the tibetan Plateau.Precipitation proves to be the prime climatic factor controlling the distribution patterns of Stipa assemblages.Form.Stipa subsessiliflora var.basiplumosa and form.Stipa glareosa normally distribute in arid habitats,but rainfall for the former is of greater variance.Form.Stipa roborowskyi and form.Stipa capillacea favor moderately moist environment.Form.Stipa purpurea and form.Stipa roborowskyi can tolerate a fairly broad range of precipitation.展开更多
Aims The latest China Vegetation Classification System(China-VCS)for natural/semi-natural vegetation has eight hierarchical levels:Association<Association-group<Subformation<Formation<Formation-group<Ve...Aims The latest China Vegetation Classification System(China-VCS)for natural/semi-natural vegetation has eight hierarchical levels:Association<Association-group<Subformation<Formation<Formation-group<Vegetation-subtype<Vegetation-type<Vegetation-type-group.The classification is based on dominant species and their growth forms and has been completed at the formation level.The principal challenge today in Chinese vegetation classification is to develop the China-VCS at levels below the formation in a way that is consistent with current international standards.We explored the following question:how can existing vegetation plot data help develop the China-VCS and improve its compatibility with other international classification systems?Methods We compiled 401 plots having plant cover and/or aboveground biomass measurements collected in six Stipa steppe formations and divided them into those with cover data(299 plots)and/or biomass data(283 plots).We applied a combination of hierarchical clustering and ordination to partition the cover and biomass data sets into formations and constituent associations.We then used supervised noise clustering to improve the classification and to identify the core plots representing each association.Diagnostic species were also identified at both association and formation levels.Finally,we compared the classification results based on cover and biomass data sets and combined these results into a comprehensive classification framework for the six formations.Important Findings Our results using cover data were comparable with those using biomass data at both formation and association levels.Three Stipa formations were classified into associations based on cover data,two based on biomass data and one based on both biomass and cover data.Twenty-seven associations were defined and proposed within the six formations,using cover or biomass data as consistent classification sections(CCSs).Both dominant species in the dominant stratum and diagnostic species from multiple strata of the core plots were used to characterize vegetation types at both formation and association levels,improving the compatibility of our classification with the International Vegetation Classification.Temperature and precipitation were found to be important climatic factors determining the distribution pattern and species composition of Stipa-dominated vegetation.We propose a framework for plotbased vegetation classification in the China-VCS,using our work with Stipa-dominated steppe vegetation as an example.We applied the concept of CCS to make optimal use of available data representing both plant cover and biomass.This study offers a model for developing the China-VCS to the association level in a way that is consistent with current international standards.展开更多
基金supported by the National Nature Science Foundation of China (Grant No.50572069)the Shanghai Science and Technology Committee (Grant Nos.0652nm002 and 0852nm06500).
文摘The quantum effect of nano-crystals is an important factor to improve nonlinear optical performance of nanocrystal embedded glasses, while controlling the size distribution and content of nano-crystals in the glass accurately is a key to obtain good quality. The auxiliary direct current electric field, accompanied with heat treatment, was applied on AgCI containing niobic tellurite glass sheet. The nucleation and crystallization of the glass were well controlled under auxiliary electric field. It was found that the average size of AgCI nano-crystal particles in the glass is smaller than that under single heat treatment, and the content of nano- crystals is higher. Therefore the third-order nonlinear optical performance of the glass was increased a lot. The local-area distributed AgCl nano-crystal particles can also be embedded into a glass sheet by using locally applied electric field.
基金supported by the National Natural Science Foundation of China(Nos.12202410 and 51906238)the China Postdoctoral Science Foundation(No.2023M733935)+4 种基金the Natural Science Foundation of Hunan Province(No.2023JJ40726)the Research Project Supported by the Shanxi Scholarship Council of China(No.2022-139)the Natural Science Foundation of Shanxi Province(Nos.20210302123017 and 2023recipient Changcheng Liu)the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province(No.20220012)the Changsha Municipal Natural Science Foundation(No.kq2208277).
文摘In order to maintain the optimal operating temperature of the battery surface and meet the demand for thermal storage technology,battery thermal management system based on phase change materials has attracted increasing interest.In this work,a kind of core-shell structured microcapsule was synthesized by an in-situ polymerization,where paraffin was used as the core,while methanol was applied to mod-ify the melamine-formaldehyde shell to reduce toxicity and improve thermal stability.Moreover,three different types of heat conductive fillers with the same content of 10 wt.%,i.e.,nano-Al_(2)O_(3),nano-ZnO and carbon nanotubes were added,generating composites.The microcapsules were uniform,and were not affected by the thermal fillers,which were evenly dispersed around.The composite sample with carbon nanotubes(10 wt.%)showed the highest thermal conductivity of 0.50 W/(m K)and latent heat of 139.64 J/g.Furthermore,according to the leakage testing and battery charge/discharge experiments,compared with Al_(2)O_(3)and ZnO,the addition of carbon nanotubes remarkably enhances the heat storage ability as latent heat from 126.98 J/g for the prepared sample with Al_(2)O_(3)and 125.86 J/g for the one with ZnO,then to 139.64 J/g,as well as dissipation performance as a cooling effect by decreasing the sur-face temperature of battery from 2%to 12%of microcapsule,composite sample with carbon nanotubes presents a broad application prospect in battery thermal management system and energy storage field.
基金Key Program of National Fundamental Scientific Research funded by the Ministry of Science and Technology of China:Integrated Scientific Investigation in Data-deficient Regions of the Tibetan Plateau(2012FY111400)Redaction of Vegetation of China(2015FY210200).
文摘Aims As a unique geographical unit of the earth,the tibetan Plateau is extensively covered by various Stipa communities.However,their vegetation features have not been reported systematically till now,especially in some scantily explored regions.In this study,we endeavor to reveal the community types,quantitative charac-teristics and climatic distribution patterns of Stipa steppes in these areas based on primary relevés obtained from fieldwork.Methods We collected a total of 223 plots in 79 study sites in the Changthang Plateau and the Yarlung Zangbo Valley,ranging from 79°E to 91°E.the categories of Stipa formations were identified according to the classification scheme in Vegetation of China and then verified by Nonmetric Multidimensional Scaling.We performed detrended correspondence analysis and detrended canonical correspondence analysis to hunt for the alteration of Stipa communities along the precipitation gradient.Quantitative characteristics including species richness,coverage,biomass as well as importance values(IV)of dominant species were calcu-lated and visualized,respectively.Important Findings Stipa steppes in scantily explored regions of the tibetan Plateau are classified into 11 formations but major formations are rather limited in number.Formation(form.)Stipa purpurea is the most widespread Stipa assemblages not only in scantily explored regions but also across the whole tibetan Plateau.the characteristics of Stipa com-munities,including coverage,species richness,productivity and IV of dominant species,demonstrate the features of typical alpine steppes on the tibetan Plateau.Precipitation proves to be the prime climatic factor controlling the distribution patterns of Stipa assemblages.Form.Stipa subsessiliflora var.basiplumosa and form.Stipa glareosa normally distribute in arid habitats,but rainfall for the former is of greater variance.Form.Stipa roborowskyi and form.Stipa capillacea favor moderately moist environment.Form.Stipa purpurea and form.Stipa roborowskyi can tolerate a fairly broad range of precipitation.
基金The work was supported by‘Strategic Priority Research Program’of the Chinese Academy of Sciences[XDA19050402]National Key Basic Research Programs of China[2015FY210200,2016YFC0502602]+1 种基金National Natural Science Foundation of China[41373081]This work was also supported by the China Scholarship Council[201604910318].
文摘Aims The latest China Vegetation Classification System(China-VCS)for natural/semi-natural vegetation has eight hierarchical levels:Association<Association-group<Subformation<Formation<Formation-group<Vegetation-subtype<Vegetation-type<Vegetation-type-group.The classification is based on dominant species and their growth forms and has been completed at the formation level.The principal challenge today in Chinese vegetation classification is to develop the China-VCS at levels below the formation in a way that is consistent with current international standards.We explored the following question:how can existing vegetation plot data help develop the China-VCS and improve its compatibility with other international classification systems?Methods We compiled 401 plots having plant cover and/or aboveground biomass measurements collected in six Stipa steppe formations and divided them into those with cover data(299 plots)and/or biomass data(283 plots).We applied a combination of hierarchical clustering and ordination to partition the cover and biomass data sets into formations and constituent associations.We then used supervised noise clustering to improve the classification and to identify the core plots representing each association.Diagnostic species were also identified at both association and formation levels.Finally,we compared the classification results based on cover and biomass data sets and combined these results into a comprehensive classification framework for the six formations.Important Findings Our results using cover data were comparable with those using biomass data at both formation and association levels.Three Stipa formations were classified into associations based on cover data,two based on biomass data and one based on both biomass and cover data.Twenty-seven associations were defined and proposed within the six formations,using cover or biomass data as consistent classification sections(CCSs).Both dominant species in the dominant stratum and diagnostic species from multiple strata of the core plots were used to characterize vegetation types at both formation and association levels,improving the compatibility of our classification with the International Vegetation Classification.Temperature and precipitation were found to be important climatic factors determining the distribution pattern and species composition of Stipa-dominated vegetation.We propose a framework for plotbased vegetation classification in the China-VCS,using our work with Stipa-dominated steppe vegetation as an example.We applied the concept of CCS to make optimal use of available data representing both plant cover and biomass.This study offers a model for developing the China-VCS to the association level in a way that is consistent with current international standards.
