Biomaterial Database

Primitive unit cell volumes obtained from unindexed convergent-beam electron diffraction patterns. 1991

Y Le Page, and D A Downham

Institute for Environmental Chemistry, NRC, Ottawa, Canada.

Provided that multiple reflection is present, a common occurrence with electron diffraction on microcrystallites, a single unindexed convergent-beam electron diffraction (CBED) pattern taken with the beam axis parallel to any direct lattice row allows the volume of the primitive cell to be calculated. The film measurements required are the diameters of the successive high-order Laue zones (HOLZ), the lengths of any two coprime vectors in the zero-order Laue zone (ZOLZ), and the angle between them. The primitive cell volume is an objective criterion allowing in a simplification in the identification of a phase under study by rapidly eliminating other possible phases. The computer program CELVOL for the calculation of the primitive cell volume from film measurements, or from literature cells, is available from the authors.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D002477	Cells	The fundamental, structural, and functional units or subunits of living organisms. They are composed of CYTOPLASM containing various ORGANELLES and a CELL MEMBRANE boundary.	Cell
D014961	X-Ray Diffraction	The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Xray Diffraction,Diffraction, X-Ray,Diffraction, Xray,Diffractions, X-Ray,Diffractions, Xray,X Ray Diffraction,X-Ray Diffractions,Xray Diffractions