Surface phonon spectra,from Ta/Al Fibonacci multilayers are studied via Brillouin scattering.Determination of the frequency positions of the Rayleigh wave and the intensity dip corresponding to the longitudinal thresh...Surface phonon spectra,from Ta/Al Fibonacci multilayers are studied via Brillouin scattering.Determination of the frequency positions of the Rayleigh wave and the intensity dip corresponding to the longitudinal threshold has enabled us to extract two effective elastic constants C_(44) and C_(11) of the whole structure.The 22.6% enhancement of the shear modulus is found in our experiment.展开更多
The complex configurations and interactions of misfit dislocations in strained GaAs/InGaAs superlattices on GaAs(001)substrates have been studied by transmission electron microscopy under the two-beam or weak beam con...The complex configurations and interactions of misfit dislocations in strained GaAs/InGaAs superlattices on GaAs(001)substrates have been studied by transmission electron microscopy under the two-beam or weak beam conditions.The observed interactions between a pair of 60°misfit dislocations and an orthogonal 60°misfit dislocation are theoretically explained.展开更多
Double-crystal x-ray diffraction has been used to measure the rocking curve of Ta/Al multilayers.The diffraction profiles of the multilayers are different.Besides the normal profile,two kinds of distorted profiles hav...Double-crystal x-ray diffraction has been used to measure the rocking curve of Ta/Al multilayers.The diffraction profiles of the multilayers are different.Besides the normal profile,two kinds of distorted profiles have been found.The simulations show that the deformed profiles of the peaks are caused by the imperfect periodicity(e.g.systematic period deviation and coexistence of two slightly different periods)in the multilayers.展开更多
The dislocations in lithium tetraborate crystal have been investigated by means of synchrotron radiation white beam topography in BSRL(Beijing Synchrotron Radiation Laboratory).The Burgers'vectors of these disloca...The dislocations in lithium tetraborate crystal have been investigated by means of synchrotron radiation white beam topography in BSRL(Beijing Synchrotron Radiation Laboratory).The Burgers'vectors of these dislocations are determined by their vanishing conditions.Both screw and edge dislocations exist in the specimen.展开更多
1-D quasiperiodic(Fibonacci)Cu/Ti metallic superlattices have been pared tn a dual magnetron sputter deposition system.X-ray scattering measurements of these samples are presented・The X-ray diffraction peaks at low an...1-D quasiperiodic(Fibonacci)Cu/Ti metallic superlattices have been pared tn a dual magnetron sputter deposition system.X-ray scattering measurements of these samples are presented・The X-ray diffraction peaks at low angles can be indexed by the projection method from the high-dimensional periodic structure.In the high angle region,there is one broad peak,which indicates that the samples are amorphous.展开更多
K_(o)-image of the Brazil twin boundary in quartz crystal by X-ray section topography and the same contrasts of the first fringes for entrance and exit surface are shown in this paper.
基金Supported by the National Natural Science Foundation of Cliina,and Science Foundation of Education Committee of Cliina,as well as Center for Material Analysis of Naiying University.
文摘Surface phonon spectra,from Ta/Al Fibonacci multilayers are studied via Brillouin scattering.Determination of the frequency positions of the Rayleigh wave and the intensity dip corresponding to the longitudinal threshold has enabled us to extract two effective elastic constants C_(44) and C_(11) of the whole structure.The 22.6% enhancement of the shear modulus is found in our experiment.
文摘The complex configurations and interactions of misfit dislocations in strained GaAs/InGaAs superlattices on GaAs(001)substrates have been studied by transmission electron microscopy under the two-beam or weak beam conditions.The observed interactions between a pair of 60°misfit dislocations and an orthogonal 60°misfit dislocation are theoretically explained.
基金Supported by the National Natural Science Foundation of China。
文摘Double-crystal x-ray diffraction has been used to measure the rocking curve of Ta/Al multilayers.The diffraction profiles of the multilayers are different.Besides the normal profile,two kinds of distorted profiles have been found.The simulations show that the deformed profiles of the peaks are caused by the imperfect periodicity(e.g.systematic period deviation and coexistence of two slightly different periods)in the multilayers.
文摘The dislocations in lithium tetraborate crystal have been investigated by means of synchrotron radiation white beam topography in BSRL(Beijing Synchrotron Radiation Laboratory).The Burgers'vectors of these dislocations are determined by their vanishing conditions.Both screw and edge dislocations exist in the specimen.
基金supported by National Natural Science Foundation of China.
文摘1-D quasiperiodic(Fibonacci)Cu/Ti metallic superlattices have been pared tn a dual magnetron sputter deposition system.X-ray scattering measurements of these samples are presented・The X-ray diffraction peaks at low angles can be indexed by the projection method from the high-dimensional periodic structure.In the high angle region,there is one broad peak,which indicates that the samples are amorphous.
文摘K_(o)-image of the Brazil twin boundary in quartz crystal by X-ray section topography and the same contrasts of the first fringes for entrance and exit surface are shown in this paper.
