We present the electronic structure and electron energy loss spectroscopy (EELS) for uranium, niobium and U3Nb in which uranium is substituted by niobium. Comparing the electronic structures and optical properties for...We present the electronic structure and electron energy loss spectroscopy (EELS) for uranium, niobium and U3Nb in which uranium is substituted by niobium. Comparing the electronic structures and optical properties for uranium, niobium and U3Nb, we found that when niobium atom replaces uranium atom in the center lattice, density of state (DOS) of U3Nb shifts downward to low energy. Niobium affects DOS for f and d electrons more than that for p and s electrons. U3Nb is similar to uranium for the electronic energy loss spectra.展开更多
In this work the electronic structure and the impurity excess of the basal and rhombohedral twin grain boundaries are investigated, using electron energy loss spectroscopy (EELS) and energy dispersive X-ray spectrosco...In this work the electronic structure and the impurity excess of the basal and rhombohedral twin grain boundaries are investigated, using electron energy loss spectroscopy (EELS) and energy dispersive X-ray spectroscopy (EDXS). The measurability of electronic structures of the twin grain boundaries are discussed by comparing theoretical density of states (DOS) from bulk material with interfacial DOS, obtained from local density functional theory (LDFT) calculations.展开更多
The primary motivation for studying how irradiation modifies the structures and properties of solid materials involves the understanding of undesirable phenomena,including irradiation-induced degradation of components...The primary motivation for studying how irradiation modifies the structures and properties of solid materials involves the understanding of undesirable phenomena,including irradiation-induced degradation of components in nuclear reactors and space exploration,and beneficial applications,including material performance tailoring through ion beam modification and defect engineering.In this work,the formation mechanism of latent tracks with different damage morphologies in LiNbO_(3)crystals under 0.09-6.17 Me V/u ion irradiation with an electronic energy loss from 2.6-13.2 ke V/nm is analyzed by experimental characterizations and numerical calculations.Irradiation-induced damage is preliminarily evaluated via the prism coupling technique to analyze the correlation between the dark-mode spectra and energy loss profiles of irradiated regions.Under the irradiation conditions of different ion velocities and electronic energy losses,different damage morphologies,from individual spherical defects to discontinuous and continuous tracks,are experimentally characterized.During ion penetration process,the ion velocity determines the spatiotemporal distribution of deposited irradiation energy induced by electronic energy loss,meaning that the two essential factors including electronic energy loss and ion velocity coaffect the track damage.The inelastic thermal spike model is used to numerically calculate the spatiotemporal evolutions of energy deposition and the corresponding atomic temperature under different irradiation conditions,and a quantitative relationship is proposed by comparison with corresponding experimentally observed track damage morphologies.The obtained quantitative relationship between irradiation conditions and track damage provides deep insight and guidance for understanding the damage behavior of crystal materials in extreme radiation environments and selecting irradiation parameters,including ion species and energies,for ion beam technique application in atomic-level defect manipulation,material modification,and micro/nanofabrication.展开更多
Noble metallic nanostructures exhibit special optical properties resulting from excitation of surface plasmons. Among the various metallic nanostructures, nanorods have attracted particular attention because of their ...Noble metallic nanostructures exhibit special optical properties resulting from excitation of surface plasmons. Among the various metallic nanostructures, nanorods have attracted particular attention because of their unique and intriguing shape-dependent plasmonic properties. Nanorods can sup- port transverse and longitudinal plasmon modes, the latter ones depending strongly on the aspect ratio of the nanorod. These modes can be routinely tuned from the visible to the near-infrared spectral regions. Although nanorods have been investigated extensively, there are few studies de- voted to nanostructures deviating from the nanorod shape. This review provides an overview of recent progress in the development of two kinds of novel quasi-one-dimensional silver nanostruc- tures, nanorice and nanocarrot, including their syntheses, crystalline characterizations, plasmonic property analyses, and performance in plasmonic sensing applications.展开更多
基金Supported by the National Key Laboratory Foundation of China (9140C6601010804)Sichuan Provincial Key Laboratory for Applied Nuclear Technology in Geology Foundation (27-7).
文摘We present the electronic structure and electron energy loss spectroscopy (EELS) for uranium, niobium and U3Nb in which uranium is substituted by niobium. Comparing the electronic structures and optical properties for uranium, niobium and U3Nb, we found that when niobium atom replaces uranium atom in the center lattice, density of state (DOS) of U3Nb shifts downward to low energy. Niobium affects DOS for f and d electrons more than that for p and s electrons. U3Nb is similar to uranium for the electronic energy loss spectra.
文摘In this work the electronic structure and the impurity excess of the basal and rhombohedral twin grain boundaries are investigated, using electron energy loss spectroscopy (EELS) and energy dispersive X-ray spectroscopy (EDXS). The measurability of electronic structures of the twin grain boundaries are discussed by comparing theoretical density of states (DOS) from bulk material with interfacial DOS, obtained from local density functional theory (LDFT) calculations.
基金supported by the National Natural Science Foundation of China(No.11875038)the National Laboratory of Heavy Ion Accelerator in Lanzhou,and the State Key Laboratory of Nuclear Physics and Technology,Peking University+2 种基金financial support from the Young Scholars Program of Shandong Universityfinancial support from the Youth Innovation Promotion Association CAS(No.2019262)supported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences,Materials Sciences and Engineering Division。
文摘The primary motivation for studying how irradiation modifies the structures and properties of solid materials involves the understanding of undesirable phenomena,including irradiation-induced degradation of components in nuclear reactors and space exploration,and beneficial applications,including material performance tailoring through ion beam modification and defect engineering.In this work,the formation mechanism of latent tracks with different damage morphologies in LiNbO_(3)crystals under 0.09-6.17 Me V/u ion irradiation with an electronic energy loss from 2.6-13.2 ke V/nm is analyzed by experimental characterizations and numerical calculations.Irradiation-induced damage is preliminarily evaluated via the prism coupling technique to analyze the correlation between the dark-mode spectra and energy loss profiles of irradiated regions.Under the irradiation conditions of different ion velocities and electronic energy losses,different damage morphologies,from individual spherical defects to discontinuous and continuous tracks,are experimentally characterized.During ion penetration process,the ion velocity determines the spatiotemporal distribution of deposited irradiation energy induced by electronic energy loss,meaning that the two essential factors including electronic energy loss and ion velocity coaffect the track damage.The inelastic thermal spike model is used to numerically calculate the spatiotemporal evolutions of energy deposition and the corresponding atomic temperature under different irradiation conditions,and a quantitative relationship is proposed by comparison with corresponding experimentally observed track damage morphologies.The obtained quantitative relationship between irradiation conditions and track damage provides deep insight and guidance for understanding the damage behavior of crystal materials in extreme radiation environments and selecting irradiation parameters,including ion species and energies,for ion beam technique application in atomic-level defect manipulation,material modification,and micro/nanofabrication.
文摘Noble metallic nanostructures exhibit special optical properties resulting from excitation of surface plasmons. Among the various metallic nanostructures, nanorods have attracted particular attention because of their unique and intriguing shape-dependent plasmonic properties. Nanorods can sup- port transverse and longitudinal plasmon modes, the latter ones depending strongly on the aspect ratio of the nanorod. These modes can be routinely tuned from the visible to the near-infrared spectral regions. Although nanorods have been investigated extensively, there are few studies de- voted to nanostructures deviating from the nanorod shape. This review provides an overview of recent progress in the development of two kinds of novel quasi-one-dimensional silver nanostruc- tures, nanorice and nanocarrot, including their syntheses, crystalline characterizations, plasmonic property analyses, and performance in plasmonic sensing applications.
基金the German Science Foundation(DFG),Bonn,Germany,for their continuous support in the field of high-pressure materials chemistrythe DFG for founding a new priority research program entitled"Synthesis,In situ Characterization and Quantum Mechanical Modeling of Earth Materials,0xides,Carbides and Nitrides at Extremely High Pressures and Temperatures"(DFG-SPP 1236)+1 种基金the DFG for financial support(contracts Kr 1805/5-1 and Kr 1805/9-1)grants from the Forschungszentrum Julich and from the Center for Computation and Communication at Aachen.
