Materials with low thermal conductivity are applied extensively in energy management,and breaking the amorphous limits of thermal conductivity to solids has attracted widespread attention from scientists.Doping is a c...Materials with low thermal conductivity are applied extensively in energy management,and breaking the amorphous limits of thermal conductivity to solids has attracted widespread attention from scientists.Doping is a common strategy for achieving low thermal conductivity that can offer abundant scattering centers in which heavier dopants always result in lower phonon group velocities and lower thermal conductivities.However,the amount of equivalent heavyatom single dopant available is limited.Unfortunately,nonequivalent heavy dopants have finite solubility because of charge imbalance.Here,we propose a charge balance strategy for SnS by substituting Sn2+with Ag^(+)and heavy Bi^(3+),improving the doping limit of Ag from 2%to 3%.Ag and Bi codoping increases the point defect concentration and introduces abundant boundaries simultaneously,scattering the phonons at both the atomic scale and nanoscale.The thermal conductivity of Ag0.03Bi0.03Sn0.94S decreased to 0.535 W·m^(−1)·K^(−1)at room temperature and 0.388 W·m^(−1)·K^(−1)at 275°C,which is below the amorphous limit of 0.450 W·m^(−1)·K^(−1)for SnS.This strategy offers a simple way to enhance the doping limit and achieve ultralow thermal conductivity in solids below the amorphous limit without precise structural modification.展开更多
The Tibetan Plateau is vital for animal husbandry in China,and relies heavily on its natural grasslands.However,grassland degradation,increasing livestock numbers,and uneven grazing practices are exacerbating the gras...The Tibetan Plateau is vital for animal husbandry in China,and relies heavily on its natural grasslands.However,grassland degradation,increasing livestock numbers,and uneven grazing practices are exacerbating the grass-livestock imbalance.Cultivated grasslands are a key strategy to address this issue.In this review,we evaluate the current status,challenges,and suggestions for developing and managing Tibetan Plateau cultivated grasslands.While discernible advancements have been made in the cultivated grasslands in this region,persistent challenges exist.These challenges stem from issues like low awareness and enthusiasm among farmers and herders,uneven cultivated grassland distribution,and limited scientific and technological contributions.Based on these challenges,we propose strengthening the promotion of artificial forage,implementing a rationalized grassland layout,and improving the scientific and technological contributions to forage species selection,sowing,management,and storage.In summary,cultivated grasslands in the Tibetan Plateau offer promising prospects but still face significant challenges.Overcoming these obstacles will require innovative approaches to unlock the full potential of cultivated grasslands in this unique ecological niche.展开更多
基金supported by the CAS Project for Young Scientists in Basic Research(YSBR-070)the National Natural Science Foundation of China(21925110,21890750,U2032161,12147105)+8 种基金the USTC Research Funds of the Double First-Class Initiative(YD2060002004)the National Key Research and Development Program of China(2022YFA1203600,2022YFA1203601,2022YFA1203602)the Natural Science Foundation of China-Anhui Joint Fund(U23A20121)the Outstanding Youth Foundation of Anhui Province(2208085J14)the Anhui Provincial Key Research and Development Project(202004a050200760)the Key R&D Program of Shandong Province(2021CXGC010302)the Users with Excellence Project of Hefei Science Center CAS(2021HSC-UE004)the Fellowship of the China Postdoctoral Science Foundation(2022M710141)the open foundation of the Key Laboratory of the Engineering Research Center of Building Energy Efficiency Control and Evaluation,Ministry of Education(AHJZNX-2023-04).
文摘Materials with low thermal conductivity are applied extensively in energy management,and breaking the amorphous limits of thermal conductivity to solids has attracted widespread attention from scientists.Doping is a common strategy for achieving low thermal conductivity that can offer abundant scattering centers in which heavier dopants always result in lower phonon group velocities and lower thermal conductivities.However,the amount of equivalent heavyatom single dopant available is limited.Unfortunately,nonequivalent heavy dopants have finite solubility because of charge imbalance.Here,we propose a charge balance strategy for SnS by substituting Sn2+with Ag^(+)and heavy Bi^(3+),improving the doping limit of Ag from 2%to 3%.Ag and Bi codoping increases the point defect concentration and introduces abundant boundaries simultaneously,scattering the phonons at both the atomic scale and nanoscale.The thermal conductivity of Ag0.03Bi0.03Sn0.94S decreased to 0.535 W·m^(−1)·K^(−1)at room temperature and 0.388 W·m^(−1)·K^(−1)at 275°C,which is below the amorphous limit of 0.450 W·m^(−1)·K^(−1)for SnS.This strategy offers a simple way to enhance the doping limit and achieve ultralow thermal conductivity in solids below the amorphous limit without precise structural modification.
基金The Central Government Leading Project for Tibetan Science and Technology Development(XZ202202YD0028C)The Entrusted Project ofthe Development Research Center,National Forestry and Grassland Administration(JYC-2022-0053)The Natural Science Foundation ofTibet(XZ202201ZR0063G).
文摘The Tibetan Plateau is vital for animal husbandry in China,and relies heavily on its natural grasslands.However,grassland degradation,increasing livestock numbers,and uneven grazing practices are exacerbating the grass-livestock imbalance.Cultivated grasslands are a key strategy to address this issue.In this review,we evaluate the current status,challenges,and suggestions for developing and managing Tibetan Plateau cultivated grasslands.While discernible advancements have been made in the cultivated grasslands in this region,persistent challenges exist.These challenges stem from issues like low awareness and enthusiasm among farmers and herders,uneven cultivated grassland distribution,and limited scientific and technological contributions.Based on these challenges,we propose strengthening the promotion of artificial forage,implementing a rationalized grassland layout,and improving the scientific and technological contributions to forage species selection,sowing,management,and storage.In summary,cultivated grasslands in the Tibetan Plateau offer promising prospects but still face significant challenges.Overcoming these obstacles will require innovative approaches to unlock the full potential of cultivated grasslands in this unique ecological niche.
