[Objectives]To explore biodiversity characteristics of Yuncheng Salt Lake and provide protection countermeasures.[Methods]According to the field survey data of 978 plant quadrats and cluster analysis,species diversity...[Objectives]To explore biodiversity characteristics of Yuncheng Salt Lake and provide protection countermeasures.[Methods]According to the field survey data of 978 plant quadrats and cluster analysis,species diversity indicators such as Margalef richness index and Shannon-Wiener index were selected to deeply explore the structure and diversity characteristics of higher plant communities in Yuncheng Salt Lake.[Results]There were 117 species belonging to 97 genera and 35 families of higher plants in Yuncheng Salt Lake,of which Asteraceae and Gramineae were dominant families,and the North Temperate Distribution Genus accounted for 27.35%of the total genera;according to profile coefficient method,the optimal cluster number was 7,which was divided into 7 plant community types,including Artemisia capillaris community and Suaeda glauca(Bunge)community;the Lolium perenne community was the highest(d=2.537),the Artemisia scoparia community was the best(E=0.658),the Suaeda salsa(L.)Pall community was the lowest(H′=1.779),and the spatial distribution of species showed a significant aggregation pattern.[Conclusions]We put forward some countermeasures for biodiversity protection,including constructing dynamic monitoring system,implementing adaptive management strategy and promoting multi-party collaborative governance,so as to provide scientific theoretical basis and practical guidance for ecological restoration and sustainable development of Yuncheng Salt Lake.展开更多
To meet the emerging demands for thermal protection materials for hypersonic aircraft,developing porous ultrahigh-temperature ceramics with both robust mechanical properties and superior thermal insulation performance...To meet the emerging demands for thermal protection materials for hypersonic aircraft,developing porous ultrahigh-temperature ceramics with both robust mechanical properties and superior thermal insulation performance is a critical challenge.Herein,we report novel porous(Ta_(0.2)Nb_(0.2)Ti_(0.2)Zr_(0.2)Hf_(0.2))C high-entropy carbide(PHEC)ceramics fabricated by a self-foaming method using commercially available metal chloride and furfuryl alcohol(FA)as precursors.The PHEC ceramics are constructed of microspheres with a size of 2µm,leading to a high porosity of 91.3%and an interconnected frame.These microspheres consist of high-entropy carbide grains(20 nm),resulting in abundant interfaces and nanosized pores in the PHEC ceramics.Due to its unique hierarchical structure,the prepared PHEC ceramics have outstanding compressive strength(28.1±2 MPa)and exceptionally low thermal conductivity(κ_(T),0.046 W·m^(-1)·K^(-1))at room temperature.This makes it a promising thermal insulation materials for ultrahigh temperature applications.This work provides a cost-effective and facile strategy for producing porous ultrahigh-temperature ceramics.展开更多
基金Supported by Central Guiding Local Science and Technology Development Fund Project Free Exploration Basic Research(YDZJSX20231A002)Yuncheng Salt Lake Ecological Environment Background Investigation and Research Project.
文摘[Objectives]To explore biodiversity characteristics of Yuncheng Salt Lake and provide protection countermeasures.[Methods]According to the field survey data of 978 plant quadrats and cluster analysis,species diversity indicators such as Margalef richness index and Shannon-Wiener index were selected to deeply explore the structure and diversity characteristics of higher plant communities in Yuncheng Salt Lake.[Results]There were 117 species belonging to 97 genera and 35 families of higher plants in Yuncheng Salt Lake,of which Asteraceae and Gramineae were dominant families,and the North Temperate Distribution Genus accounted for 27.35%of the total genera;according to profile coefficient method,the optimal cluster number was 7,which was divided into 7 plant community types,including Artemisia capillaris community and Suaeda glauca(Bunge)community;the Lolium perenne community was the highest(d=2.537),the Artemisia scoparia community was the best(E=0.658),the Suaeda salsa(L.)Pall community was the lowest(H′=1.779),and the spatial distribution of species showed a significant aggregation pattern.[Conclusions]We put forward some countermeasures for biodiversity protection,including constructing dynamic monitoring system,implementing adaptive management strategy and promoting multi-party collaborative governance,so as to provide scientific theoretical basis and practical guidance for ecological restoration and sustainable development of Yuncheng Salt Lake.
基金This research was supported by the National Natural Science Foundation of China(Nos.52173299 and 52372087)the Natural Science Foundation of Shaanxi Province(No.2021JZ-51).
文摘To meet the emerging demands for thermal protection materials for hypersonic aircraft,developing porous ultrahigh-temperature ceramics with both robust mechanical properties and superior thermal insulation performance is a critical challenge.Herein,we report novel porous(Ta_(0.2)Nb_(0.2)Ti_(0.2)Zr_(0.2)Hf_(0.2))C high-entropy carbide(PHEC)ceramics fabricated by a self-foaming method using commercially available metal chloride and furfuryl alcohol(FA)as precursors.The PHEC ceramics are constructed of microspheres with a size of 2µm,leading to a high porosity of 91.3%and an interconnected frame.These microspheres consist of high-entropy carbide grains(20 nm),resulting in abundant interfaces and nanosized pores in the PHEC ceramics.Due to its unique hierarchical structure,the prepared PHEC ceramics have outstanding compressive strength(28.1±2 MPa)and exceptionally low thermal conductivity(κ_(T),0.046 W·m^(-1)·K^(-1))at room temperature.This makes it a promising thermal insulation materials for ultrahigh temperature applications.This work provides a cost-effective and facile strategy for producing porous ultrahigh-temperature ceramics.
