convergent beams造句

• This technique is called Convergent Beam Electron Diffraction ( CBED ) and can reveal the full three-dimensional symmetry of the crystal.
• This image was recorded in convergent beam, because that too reduces the range of contrasts that have to be recorded on film.
• Precession electron diffraction is typically conducted using accelerating voltages between 100-400 kV . Patterns can be formed under parallel or convergent beam conditions.
• The colloid is placed in a light-absorbing, dark enclosure, and illuminated with a convergent beam of intense light entering from one side.
• This is most significant for conditions of convergent beam illumination . 50 nm is a general lower limit on probe size for standard TEMs operating at high precession angles ( > 30mRad ), but can be surpassed in C s corrected instruments.
• In practice, Kikuchi lines are easily seen in thick regions of either selected area or convergent beam electron diffraction patterns, but difficult to see in diffraction from crystals much less than 100 nm in size ( where lattice-fringe visibility effects become important instead ).
• In convergent beam electron diffraction ( CBED ) where a non-parallel, i . e . converging, electron wavefront is produced by concentrating the electron beam into a fine probe at the sample surface, the interaction of the convergent beam can provide information beyond structural data such as sample thickness.
• In convergent beam electron diffraction ( CBED ) where a non-parallel, i . e . converging, electron wavefront is produced by concentrating the electron beam into a fine probe at the sample surface, the interaction of the convergent beam can provide information beyond structural data such as sample thickness.
• They are then accelerated and formed into a narrow convergent beam by an electric field produced by three electrodes : the electron emitting strap, the cathode connected to the negative pole of the high ( accelerating ) voltage power supply ( 30-200 kV ) and the positive high voltage electrode, the anode.