The increasing intensity and frequency of sand-dust storms in China has led to greater prominence of associated environmentaland health issues. Many studies have focused on the health effects of air particulate contam...The increasing intensity and frequency of sand-dust storms in China has led to greater prominence of associated environmentaland health issues. Many studies have focused on the health effects of air particulate contaminants, but fewformal investigations have studied the effects of sand-dust storms on human and animal health. The aim of this study wasto investigate the effects of dust storms on rat lung by using high resolution computed tomography (HRCT) and blood gasanalysis through a wind tunnel simulating. We found that the rat lung damage effects can be detected by the HRCT imagingafter exposure to sand-dust storm environments, but had no obvious result through blood gas analysis. Exposure durationspositively correlated with the damage degree to lung tissue. These will provide some evidence for clinical diagnosis ofnon-occupational pneumoconiosis.展开更多
A key issue in metallic uranium and its related actinide compounds is the character of the f electrons, whether it is localized or itinerant.Here we grew well ordered uranium films on a W(110) substrate.The surface to...A key issue in metallic uranium and its related actinide compounds is the character of the f electrons, whether it is localized or itinerant.Here we grew well ordered uranium films on a W(110) substrate.The surface topography was investigated by scanning tunneling microscopy.The Fermi surface and band structure of the grown films were studied by angle-resolved photoemission spectroscopy.Large spectral weight can be observed around the Fermi level, which mainly comes from the f states.Additionally, we provided direct evidence that the f bands hybridize with the conduction bands in the uranium ordered films, which is different from previously reported mechanism of the direct f–f interaction.We propose that the above two mechanisms both exist in this system by manifesting themselves in different momentum spaces.Our results give a comprehensive study of the ordered uranium films and may throw new light on the study of the 5 f-electron character and physical properties of metallic uranium and other related actinide materials.展开更多
The cooper pairs in the heavy-fermion superconductor CeCu2Si2 are formed of heavy fermions.Therefore,the heavy fermions are fundamental to the emergence of unconventional superconductivity and associated non-Fermi-liq...The cooper pairs in the heavy-fermion superconductor CeCu2Si2 are formed of heavy fermions.Therefore,the heavy fermions are fundamental to the emergence of unconventional superconductivity and associated non-Fermi-liquid behavior in the normal state.The interplay between localization and itinerancy manifested on the electronic structure is key for understanding the heavyfermion behavior.Here,via the first-principle density functional theory(DFT)combined with single-site dynamical mean-field theory(DMFT),we investigate the temperature(T)evolution of the electronic structure of CeCu2Si2 in the normal state,focusing on the role of the 4f states in the low energy regime.Two characteristic temperature scales of this evolution,which accompanied the heavy-fermion formation,are established.The coherence onset temperature is around 130K,whereas the heavy-fermion band formation temperature is between 40 and 80K;both characteristic temperature scales are higher than the transport coherence temperature.Furthermore,the heavy-fermion formation is confirmed by calculating its effective mass variation with the temperature.Based on the calculated T-dependent evolution of the 4 f orbital occupancy and electronic structure,an explanation on the behavior of the temperature evolution of the correlation strength of CeCu2Si2 is provided.Our results offer a comprehensive microscopic picture of the heavy-fermion formation in CeCu2Si2,which is essential for further understanding the emergent superconducting pairing mechanism.展开更多
The anodic behavior of cerium (Ce) in A1C13-1-ethyl-3-methyl-imidazolium chloride (A1CI3-EMIC) ionic liquid has been investigated. Linear sweep voltammetry (LSV), electrochemical impedance spectra (EIS), Raman...The anodic behavior of cerium (Ce) in A1C13-1-ethyl-3-methyl-imidazolium chloride (A1CI3-EMIC) ionic liquid has been investigated. Linear sweep voltammetry (LSV), electrochemical impedance spectra (EIS), Raman spectra, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were carried out to state the process and mechanism during anodic reaction. The results show that Ce can be electrochemically oxidized and dissolved in the ionic liquid. The oxide film of Ce markedly affects its anodic behavior by blocking the dissolution of the underlying metal. Moreover. the dissolution of metal surface brings about the stripping of the oxide film on Ce, thus leading to an oxide free surface. This work demonstrates a theoretical foundation for electrolytic etching of Ce in ionic liquids,展开更多
基金supported by the National Natural Science Foundation of China (41161019, 41461020)
文摘The increasing intensity and frequency of sand-dust storms in China has led to greater prominence of associated environmentaland health issues. Many studies have focused on the health effects of air particulate contaminants, but fewformal investigations have studied the effects of sand-dust storms on human and animal health. The aim of this study wasto investigate the effects of dust storms on rat lung by using high resolution computed tomography (HRCT) and blood gasanalysis through a wind tunnel simulating. We found that the rat lung damage effects can be detected by the HRCT imagingafter exposure to sand-dust storm environments, but had no obvious result through blood gas analysis. Exposure durationspositively correlated with the damage degree to lung tissue. These will provide some evidence for clinical diagnosis ofnon-occupational pneumoconiosis.
基金Project supported by the National Natural Science Foundation of China(Grant No.11874330)Science Challenge Project,China(Grant No.TZ2016004)the National Key Research and Development Program of China(Grant No.2017YFA0303104)
文摘A key issue in metallic uranium and its related actinide compounds is the character of the f electrons, whether it is localized or itinerant.Here we grew well ordered uranium films on a W(110) substrate.The surface topography was investigated by scanning tunneling microscopy.The Fermi surface and band structure of the grown films were studied by angle-resolved photoemission spectroscopy.Large spectral weight can be observed around the Fermi level, which mainly comes from the f states.Additionally, we provided direct evidence that the f bands hybridize with the conduction bands in the uranium ordered films, which is different from previously reported mechanism of the direct f–f interaction.We propose that the above two mechanisms both exist in this system by manifesting themselves in different momentum spaces.Our results give a comprehensive study of the ordered uranium films and may throw new light on the study of the 5 f-electron character and physical properties of metallic uranium and other related actinide materials.
基金supported by the National Natural Science Foundation of China(Grant No.11774320)the Dean Foundation of China Academy of Engineering Physics(Grant No.201501040)。
文摘The cooper pairs in the heavy-fermion superconductor CeCu2Si2 are formed of heavy fermions.Therefore,the heavy fermions are fundamental to the emergence of unconventional superconductivity and associated non-Fermi-liquid behavior in the normal state.The interplay between localization and itinerancy manifested on the electronic structure is key for understanding the heavyfermion behavior.Here,via the first-principle density functional theory(DFT)combined with single-site dynamical mean-field theory(DMFT),we investigate the temperature(T)evolution of the electronic structure of CeCu2Si2 in the normal state,focusing on the role of the 4f states in the low energy regime.Two characteristic temperature scales of this evolution,which accompanied the heavy-fermion formation,are established.The coherence onset temperature is around 130K,whereas the heavy-fermion band formation temperature is between 40 and 80K;both characteristic temperature scales are higher than the transport coherence temperature.Furthermore,the heavy-fermion formation is confirmed by calculating its effective mass variation with the temperature.Based on the calculated T-dependent evolution of the 4 f orbital occupancy and electronic structure,an explanation on the behavior of the temperature evolution of the correlation strength of CeCu2Si2 is provided.Our results offer a comprehensive microscopic picture of the heavy-fermion formation in CeCu2Si2,which is essential for further understanding the emergent superconducting pairing mechanism.
基金Project supproted by Discipline Development Foundation of China Academy of Engineering and Physics(2015B0301065)
文摘The anodic behavior of cerium (Ce) in A1C13-1-ethyl-3-methyl-imidazolium chloride (A1CI3-EMIC) ionic liquid has been investigated. Linear sweep voltammetry (LSV), electrochemical impedance spectra (EIS), Raman spectra, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were carried out to state the process and mechanism during anodic reaction. The results show that Ce can be electrochemically oxidized and dissolved in the ionic liquid. The oxide film of Ce markedly affects its anodic behavior by blocking the dissolution of the underlying metal. Moreover. the dissolution of metal surface brings about the stripping of the oxide film on Ce, thus leading to an oxide free surface. This work demonstrates a theoretical foundation for electrolytic etching of Ce in ionic liquids,