Observation of epitaxial overlayer of metals at atomic level has been successfully observed in field ion microscope with 5 ns pulsed-laser heating.The condition of superlattice layer growth depends on the surface free...Observation of epitaxial overlayer of metals at atomic level has been successfully observed in field ion microscope with 5 ns pulsed-laser heating.The condition of superlattice layer growth depends on the surface free energy and the lattice misfit.Many defects,such as vacancies,va- cancy clusters,voids,dislocations and twins are produced during epitaxial growth because of the lattice misfit even though the condition of surface free energy is satisfied.Alloying is ob- served to occur on the surface of the metal during the epitaxial growth.Diffusion is probably via the exchange mechanism.展开更多
The microstructural evolution and precipitation hardening of an Elinvar alloy doped with Ti and Al during isothermal aging at 700℃ have been investigated by atom probe field ion microscopy and microhardness measureme...The microstructural evolution and precipitation hardening of an Elinvar alloy doped with Ti and Al during isothermal aging at 700℃ have been investigated by atom probe field ion microscopy and microhardness measurements.The γ′ precipiates are spherical and coherent with the matrix.The chemical composition of the precipitates are(Ni_(0.53)Fe_(0.47)_3 (Ti_(0.(?))Al_(0.4)). During aging,a Lifshitz-Wagner type dissolution and coarsening reaction of the precipitates has been observed,The hardness of the material varies with the aging time and reaches maxi- mum when the average diameter of the precipitates was about 11 nm.展开更多
The work described in this paper is a study of gold adsorption on the whole tip surface of iridium field emitter. The study has been carried out using field emission microscope. Changes in electron work function of th...The work described in this paper is a study of gold adsorption on the whole tip surface of iridium field emitter. The study has been carried out using field emission microscope. Changes in electron work function of the iridium substrate which are produced by vapor of deposition of submonolayers of gold in ultra high vacuum have been measured by noting the changes in the slope of Fowler-Nordheim plots. The same procedure for studying the adsorption of copper on iridium?[1] was followed to study the adsorption of gold on iridium. Adsorption of gold was examined on the iridium surface containing the (100) ring which could not be removed thermally.展开更多
The luminescence from lanthanide ions has potential applications in light emitting diodes,biomedical,solar cells,sensors,display,etc.However,the luminescence is suffered from the various problems,such as low luminesce...The luminescence from lanthanide ions has potential applications in light emitting diodes,biomedical,solar cells,sensors,display,etc.However,the luminescence is suffered from the various problems,such as low luminescence efficiency and inharmonious wavelength for energy transfer.Magnetic field is an efficient method to modulate the wavelength and intensity of luminescence from lanthanide ions.Magnetic field redistributes the populated electrons in the excited states to tune the wavelength of lanthanide ions by Zeeman effect,mixing effect,and quantum confinement effect.Magnetic field enhances or suppresses the luminescence intensity by the administration of cross-relaxation,energy transfer,and Boltzmann population.In this review,we first introduce the various phenomena and mechanisms of magnetic field modulated downshift luminescence from lanthanide ions,including Zeeman effect,cross-relaxation,crystal structure,absorption,quantum confinement effect,and magneticoptical hysteresis.Then,we explain the regulation of upconversion luminescence by magnetic field,containing energy transfer and mixing effect.Finally,different options regarding how to understand the mechanism of magnetic field-modulated luminescence from lanthanide ions in the future are outlined.展开更多
The behavior of Cu during the crystallization processes in Fe-Zr-B amorphous alloy was studied by atom probe field ion microscopy and transmission electron microscopy. It was found that Cu atoms formed clusters prior ...The behavior of Cu during the crystallization processes in Fe-Zr-B amorphous alloy was studied by atom probe field ion microscopy and transmission electron microscopy. It was found that Cu atoms formed clusters prior to the crystallization reaction. During the crystallization, Cu enriched clusters provided nucleation sites for α-Fe phase so that the nucleation density of α-Fe phase is increased.展开更多
文摘Observation of epitaxial overlayer of metals at atomic level has been successfully observed in field ion microscope with 5 ns pulsed-laser heating.The condition of superlattice layer growth depends on the surface free energy and the lattice misfit.Many defects,such as vacancies,va- cancy clusters,voids,dislocations and twins are produced during epitaxial growth because of the lattice misfit even though the condition of surface free energy is satisfied.Alloying is ob- served to occur on the surface of the metal during the epitaxial growth.Diffusion is probably via the exchange mechanism.
文摘The microstructural evolution and precipitation hardening of an Elinvar alloy doped with Ti and Al during isothermal aging at 700℃ have been investigated by atom probe field ion microscopy and microhardness measurements.The γ′ precipiates are spherical and coherent with the matrix.The chemical composition of the precipitates are(Ni_(0.53)Fe_(0.47)_3 (Ti_(0.(?))Al_(0.4)). During aging,a Lifshitz-Wagner type dissolution and coarsening reaction of the precipitates has been observed,The hardness of the material varies with the aging time and reaches maxi- mum when the average diameter of the precipitates was about 11 nm.
文摘The work described in this paper is a study of gold adsorption on the whole tip surface of iridium field emitter. The study has been carried out using field emission microscope. Changes in electron work function of the iridium substrate which are produced by vapor of deposition of submonolayers of gold in ultra high vacuum have been measured by noting the changes in the slope of Fowler-Nordheim plots. The same procedure for studying the adsorption of copper on iridium?[1] was followed to study the adsorption of gold on iridium. Adsorption of gold was examined on the iridium surface containing the (100) ring which could not be removed thermally.
基金financially supported by National Natural Science Foundation of China(No.11704081)Guangxi Natural Science Foundation(No.2017GXNSFBA198229)+2 种基金the Scientific Research Project for Higher Education of Guangxi Zhuang Autonomous Region(No.XBZ170336)the Doctoral Scientific Research Foundation of Guangxi University(No.BRP180253)The Improvement of Basic Ability for Youth Teachers in Guangxi Education Authority(No.2017KY0020)。
文摘The luminescence from lanthanide ions has potential applications in light emitting diodes,biomedical,solar cells,sensors,display,etc.However,the luminescence is suffered from the various problems,such as low luminescence efficiency and inharmonious wavelength for energy transfer.Magnetic field is an efficient method to modulate the wavelength and intensity of luminescence from lanthanide ions.Magnetic field redistributes the populated electrons in the excited states to tune the wavelength of lanthanide ions by Zeeman effect,mixing effect,and quantum confinement effect.Magnetic field enhances or suppresses the luminescence intensity by the administration of cross-relaxation,energy transfer,and Boltzmann population.In this review,we first introduce the various phenomena and mechanisms of magnetic field modulated downshift luminescence from lanthanide ions,including Zeeman effect,cross-relaxation,crystal structure,absorption,quantum confinement effect,and magneticoptical hysteresis.Then,we explain the regulation of upconversion luminescence by magnetic field,containing energy transfer and mixing effect.Finally,different options regarding how to understand the mechanism of magnetic field-modulated luminescence from lanthanide ions in the future are outlined.
文摘The behavior of Cu during the crystallization processes in Fe-Zr-B amorphous alloy was studied by atom probe field ion microscopy and transmission electron microscopy. It was found that Cu atoms formed clusters prior to the crystallization reaction. During the crystallization, Cu enriched clusters provided nucleation sites for α-Fe phase so that the nucleation density of α-Fe phase is increased.
