Loop-shaped contrasts were observed in the as-grown Al70.3Pd2o.6Mn9.1 icosahedral quasicrystal(IQC)by means of x-ray diffraction topography(Lang's method).One possible direction of the apparent Burger vectors of l...Loop-shaped contrasts were observed in the as-grown Al70.3Pd2o.6Mn9.1 icosahedral quasicrystal(IQC)by means of x-ray diffraction topography(Lang's method).One possible direction of the apparent Burger vectors of loopshaped defects(LSDs)was determined to be B=[110101]by the invisibility criterion,whose physical component is parallel to the two-fold axis 1/τ1/0,1/1,0/1 of the IQC.Apart from the relaxation of strain fields around the faceted dodecahedral holes and lamellar precipitates,LSDs may well originate from the growth of the quasicrystal,which shows that these defects could be a kind of intrinsic defect in the quasicrystals.展开更多
Structure model of charge-ordered La_0.33 Ca_0.67 MnO_3, perovskite is one of current focused study in condensed matter physics. There are great discrepancies in previous studies in this field. Our transmission electr...Structure model of charge-ordered La_0.33 Ca_0.67 MnO_3, perovskite is one of current focused study in condensed matter physics. There are great discrepancies in previous studies in this field. Our transmission electron microscopy study confirms Wigner crystal model with transverse displacement and is not consisent with the hi-stripe model with longitudinal displacement. We observed incommensurate modulation and anti-phase domains with a displacement vector a_co/3 in charge--ordered La_0.33 Ca_0.67 MnO_3, perovskite.展开更多
A method to evaluate some Fourier integrals is extended from two-dimensional (2-D) and three dimensional (3-D) spaces ton-dimensional (n-D) space, which are often used in the elasticity theory of dislocations in quasi...A method to evaluate some Fourier integrals is extended from two-dimensional (2-D) and three dimensional (3-D) spaces ton-dimensional (n-D) space, which are often used in the elasticity theory of dislocations in quasicrystals. Some key formulae have been given.展开更多
The procedure of simulating convergent beam electron diffraction (CBED) pattern of quasicrystals by dynamical theory is described. The simulated patterns are generally coincide with the experimental patterns. The var...The procedure of simulating convergent beam electron diffraction (CBED) pattern of quasicrystals by dynamical theory is described. The simulated patterns are generally coincide with the experimental patterns. The variations of intensity distribution in CBED pattern with the amplitude and phase of the structure factor of quasicrystal are calculated with dynamical theory. The sensitivity of intensity distribution to the structure factor is investigated.展开更多
By changing the diffraction beams involved in rocking curve calculation with matrix method,according to the incident beam direction,the required computing time may be considerably reduced.
基金Supported by the Sino-France Cooperative Project under Grant No.4B1/002partially by the National Natural Science Foundation of China under Grant No.19974031he Research Fund for the Doctoral Program of Higher Education of China.
文摘Loop-shaped contrasts were observed in the as-grown Al70.3Pd2o.6Mn9.1 icosahedral quasicrystal(IQC)by means of x-ray diffraction topography(Lang's method).One possible direction of the apparent Burger vectors of loopshaped defects(LSDs)was determined to be B=[110101]by the invisibility criterion,whose physical component is parallel to the two-fold axis 1/τ1/0,1/1,0/1 of the IQC.Apart from the relaxation of strain fields around the faceted dodecahedral holes and lamellar precipitates,LSDs may well originate from the growth of the quasicrystal,which shows that these defects could be a kind of intrinsic defect in the quasicrystals.
文摘Structure model of charge-ordered La_0.33 Ca_0.67 MnO_3, perovskite is one of current focused study in condensed matter physics. There are great discrepancies in previous studies in this field. Our transmission electron microscopy study confirms Wigner crystal model with transverse displacement and is not consisent with the hi-stripe model with longitudinal displacement. We observed incommensurate modulation and anti-phase domains with a displacement vector a_co/3 in charge--ordered La_0.33 Ca_0.67 MnO_3, perovskite.
基金Supported by the Natural Science Foundation of Hubei( 992 0 p30 7)
文摘A method to evaluate some Fourier integrals is extended from two-dimensional (2-D) and three dimensional (3-D) spaces ton-dimensional (n-D) space, which are often used in the elasticity theory of dislocations in quasicrystals. Some key formulae have been given.
基金the National Natural Science Foundation of China!59871034
文摘The procedure of simulating convergent beam electron diffraction (CBED) pattern of quasicrystals by dynamical theory is described. The simulated patterns are generally coincide with the experimental patterns. The variations of intensity distribution in CBED pattern with the amplitude and phase of the structure factor of quasicrystal are calculated with dynamical theory. The sensitivity of intensity distribution to the structure factor is investigated.
基金Supported by the Science Fund of the Chinese Academy of Sciences。
文摘By changing the diffraction beams involved in rocking curve calculation with matrix method,according to the incident beam direction,the required computing time may be considerably reduced.
