The purpose of the work is to identify the acoustic emission （AE） signal in the melt and from the interphase during the crystal growth and to establish the connection between issue parameters： the number of signal ...The purpose of the work is to identify the acoustic emission （AE） signal in the melt and from the interphase during the crystal growth and to establish the connection between issue parameters： the number of signal events of frequency and the signal power with the growth conditions of temperature gradient and crystallization rate. Experiments on single crystal growth were carried out using hardware and software system which allows to perform spectral Fourier analysis of AE signals and to simultaneously remove the cooling curve for the entire period of crystallization. On the basis of spectral analysis of AE signals, a theoretical model of clusters in the aluminum melt was designed. The experimental results indicate an uneven abrupt advancement of the interface according to the configuration of each individual cluster.展开更多
Multiwalled-carbon nanotubes coated with nano-crystalline zinc oxide （ZnO） was prepared by in situ growth of nano zinc oxide on the surfaces of carbon nanotubes through hydrothermal method. X-ray diffraction, transm...Multiwalled-carbon nanotubes coated with nano-crystalline zinc oxide （ZnO） was prepared by in situ growth of nano zinc oxide on the surfaces of carbon nanotubes through hydrothermal method. X-ray diffraction, transmission electron microscopy and scanning electron microscopy analysis techniques were used to characterize the samples. It was observed that a layer of nano-crystalline ZnO with the wurtzite hexagonal crystal structure was uniformly coated on the nanotube surfaces with good adhesion, which resulted in the formation of a novel ZnO-nanotuhe nano composite. In this work, the carbon nanotubes decorated by metal oxide nanoparticles were synthesized by a simple chemical-solution route which is suitable for the large-scale production with low cost.展开更多
文摘The purpose of the work is to identify the acoustic emission （AE） signal in the melt and from the interphase during the crystal growth and to establish the connection between issue parameters： the number of signal events of frequency and the signal power with the growth conditions of temperature gradient and crystallization rate. Experiments on single crystal growth were carried out using hardware and software system which allows to perform spectral Fourier analysis of AE signals and to simultaneously remove the cooling curve for the entire period of crystallization. On the basis of spectral analysis of AE signals, a theoretical model of clusters in the aluminum melt was designed. The experimental results indicate an uneven abrupt advancement of the interface according to the configuration of each individual cluster.
文摘Multiwalled-carbon nanotubes coated with nano-crystalline zinc oxide （ZnO） was prepared by in situ growth of nano zinc oxide on the surfaces of carbon nanotubes through hydrothermal method. X-ray diffraction, transmission electron microscopy and scanning electron microscopy analysis techniques were used to characterize the samples. It was observed that a layer of nano-crystalline ZnO with the wurtzite hexagonal crystal structure was uniformly coated on the nanotube surfaces with good adhesion, which resulted in the formation of a novel ZnO-nanotuhe nano composite. In this work, the carbon nanotubes decorated by metal oxide nanoparticles were synthesized by a simple chemical-solution route which is suitable for the large-scale production with low cost.
