In the post-Moore era, as the energy consumption of micro-nano electronic devices rapidly increases, near-field radiative heat transfer(NFRHT) with super-Planckian phenomena has gradually shown great potential for app...In the post-Moore era, as the energy consumption of micro-nano electronic devices rapidly increases, near-field radiative heat transfer(NFRHT) with super-Planckian phenomena has gradually shown great potential for applications in efficient and ultrafast thermal modulation and energy conversion. Recently, hyperbolic materials, an important class of anisotropic materials with hyperbolic isofrequency contours, have been intensively investigated. As an exotic optical platform, hyperbolic materials bring tremendous new opportunities for NFRHT from theoretical advances to experimental designs. To date, there have been considerable achievements in NFRHT for hyperbolic materials, which range from the establishment of different unprecedented heat transport phenomena to various potential applications. This review concisely introduces the basic physics of NFRHT for hyperbolic materials, lays out the theoretical methods to address NFRHT for hyperbolic materials, and highlights unique behaviors as realized in different hyperbolic materials and the resulting applications. Finally, key challenges and opportunities of the NFRHT for hyperbolic materials in terms of fundamental physics, experimental validations, and potential applications are outlined and discussed.展开更多
Taklamakan Desert(TD)has been characterized by numerous heatwaves and dust storms,leading to negative effects on societies and ecosystems at regional and global scales.However,the association between heatwaves and dus...Taklamakan Desert(TD)has been characterized by numerous heatwaves and dust storms,leading to negative effects on societies and ecosystems at regional and global scales.However,the association between heatwaves and dust storms is poorly known.In this study,we describe the association between heatwaves and dust events and propose a mechanism for such compound events in the TD.The results show that,from 1993 to 2022,the frequency and intensity of heatwaves in the TD have increased at a rate of 0.21 days year^(-1)and 0.02℃ year^(-1),respectively.More than 40% of heatwaves existed with dust events,which significantly lagged behind heatwaves.Mechanically,the higher the air temperature,the hotter and drier the soil,leading to more dust emissions in the TD.In high-occurrence heatwave years,a large-scale wave train of“cyclone-anticyclone-cyclone”in the northwest-southeast direction was found,with the anticyclone of which hovered over the TD region.The anomalous anticyclones favored the formation and maintenance of heatwaves,and subsequent anomalous cyclones in the wave train triggered strong dust events followed by heatwaves.With climate warming,the compound events of heatwave and dust storm are becoming bigger hazards threatening the socioeconomic and ecological security in the TD,the profound study of which is critical to understanding regional extreme responses.展开更多
全球碳循环中被长期忽视的沙漠生态系统,可能会封存大量CO2发挥碳汇作用.塔克拉玛干沙漠是世界第二大流动沙漠,其碳汇作用的内部过程以及气候变化下碳汇的长期趋势仍不明确.研究发现,流沙的热量波动引起含CO2的土壤空气的膨胀/收缩和盐...全球碳循环中被长期忽视的沙漠生态系统,可能会封存大量CO2发挥碳汇作用.塔克拉玛干沙漠是世界第二大流动沙漠,其碳汇作用的内部过程以及气候变化下碳汇的长期趋势仍不明确.研究发现,流沙的热量波动引起含CO2的土壤空气的膨胀/收缩和盐碱的化学作用共同控制了塔克拉玛干沙漠流沙CO2交换作用.这些过程的相互作用使得该沙漠流沙表现出明显的碳汇作用(速率为1.60×106 t a-1).如果以塔克拉玛干沙漠流沙的CO2吸收量为平均状态,那么全球流动沙漠每年可吸收CO2约2.125×108 t.但是,随气候变化,流沙温差的增大会刺激流沙中空气膨胀,向大气中注入更多的CO2,导致未来流沙碳汇能力逐渐减少.该发现对于评估全球碳循环、缩小碳失汇差额和重新认识沙漠生态系统在碳循环中的地位具有重要作用.展开更多
基金supported by the Natural Science Foundation of Shandong Province (ZR2020LLZ004)the National Natural Science Foundation of China (Grant No.52106099),the National Natural Science Foundation of China (Grant No.52076056)the Fundamental Research Funds for the Central Universities (Grant No.AUGA5710094020)。
文摘In the post-Moore era, as the energy consumption of micro-nano electronic devices rapidly increases, near-field radiative heat transfer(NFRHT) with super-Planckian phenomena has gradually shown great potential for applications in efficient and ultrafast thermal modulation and energy conversion. Recently, hyperbolic materials, an important class of anisotropic materials with hyperbolic isofrequency contours, have been intensively investigated. As an exotic optical platform, hyperbolic materials bring tremendous new opportunities for NFRHT from theoretical advances to experimental designs. To date, there have been considerable achievements in NFRHT for hyperbolic materials, which range from the establishment of different unprecedented heat transport phenomena to various potential applications. This review concisely introduces the basic physics of NFRHT for hyperbolic materials, lays out the theoretical methods to address NFRHT for hyperbolic materials, and highlights unique behaviors as realized in different hyperbolic materials and the resulting applications. Finally, key challenges and opportunities of the NFRHT for hyperbolic materials in terms of fundamental physics, experimental validations, and potential applications are outlined and discussed.
基金supported by the National Natural Science Foundation of China(Grant Nos.41991231 and 91937302)the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2022-kb11)。
文摘Taklamakan Desert(TD)has been characterized by numerous heatwaves and dust storms,leading to negative effects on societies and ecosystems at regional and global scales.However,the association between heatwaves and dust storms is poorly known.In this study,we describe the association between heatwaves and dust events and propose a mechanism for such compound events in the TD.The results show that,from 1993 to 2022,the frequency and intensity of heatwaves in the TD have increased at a rate of 0.21 days year^(-1)and 0.02℃ year^(-1),respectively.More than 40% of heatwaves existed with dust events,which significantly lagged behind heatwaves.Mechanically,the higher the air temperature,the hotter and drier the soil,leading to more dust emissions in the TD.In high-occurrence heatwave years,a large-scale wave train of“cyclone-anticyclone-cyclone”in the northwest-southeast direction was found,with the anticyclone of which hovered over the TD region.The anomalous anticyclones favored the formation and maintenance of heatwaves,and subsequent anomalous cyclones in the wave train triggered strong dust events followed by heatwaves.With climate warming,the compound events of heatwave and dust storm are becoming bigger hazards threatening the socioeconomic and ecological security in the TD,the profound study of which is critical to understanding regional extreme responses.
基金the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0602)the National Natural Science Foundation of China(41521004,41975010 and 41175140)the China University Research Talents Recruitment Program(B13045).
文摘全球碳循环中被长期忽视的沙漠生态系统,可能会封存大量CO2发挥碳汇作用.塔克拉玛干沙漠是世界第二大流动沙漠,其碳汇作用的内部过程以及气候变化下碳汇的长期趋势仍不明确.研究发现,流沙的热量波动引起含CO2的土壤空气的膨胀/收缩和盐碱的化学作用共同控制了塔克拉玛干沙漠流沙CO2交换作用.这些过程的相互作用使得该沙漠流沙表现出明显的碳汇作用(速率为1.60×106 t a-1).如果以塔克拉玛干沙漠流沙的CO2吸收量为平均状态,那么全球流动沙漠每年可吸收CO2约2.125×108 t.但是,随气候变化,流沙温差的增大会刺激流沙中空气膨胀,向大气中注入更多的CO2,导致未来流沙碳汇能力逐渐减少.该发现对于评估全球碳循环、缩小碳失汇差额和重新认识沙漠生态系统在碳循环中的地位具有重要作用.