Key points in crystallography Miller indices,Bravis-Miller indices for hexagonal structure Lattice spacing calculation Reciprocal lattice <-real lattice Know how to read a crystal structure Table 1.4 Crystallographic data for FeC,iron carbide or cementite,which exists in equilibrium with a-Fe in most steels Pearson Structure symbol a,b,c x,B,7 Point Phase type space group (nm) ) Atoms set X Occ CFe3 CFe3 oP16 Pnma 0.50890 C 4c 890250450 100 0.67433 Fe1 4c 036250852 100 0.45235 Fe2 8d 186063328100
Key points in crystallography • Miller indices, Bravis-Miller indices for hexagonal structure • Lattice spacing calculation • Reciprocal lattice <-> real lattice • Know how to read a crystal structure
Physics of X-ray radiation
Physics of X-ray radiation
Physics of X-ray radiation ·Vavelength of X-ray ·X-ray absorption ·X-ray generators ·Safety issues Wilhelm Conrad Rontgen and the first human X-ray photo
Physics of X-ray radiation • Wavelength of X-ray • X-ray absorption • X-ray generators • Safety issues Wilhelm Conrad Röntgen and the first human X-ray photo
Wavelength of X-ray E Wavelength,入 E,=E,sin2x(经W k H Wavelength,入 5 g ultraviolet shortwave gamma X-rays rays infrared radar FMTV AM rays rays 10-4 10-2 10一109 10-6 0、021 102 104 Wavelength (meters) Visible Light 400 500 600 700 Wavelength(nanometers)
Wavelength of X-ray E E x t x,t 0 sin 2 H H x t x,t 0 sin 2 sin 2 ( ) , 0 vt x E x t E
X-ray tube (p.48 of textbook) U 3 1一高压变压器 2一灯丝变压器3一X射线管 4一阳极5一阴极6一电子7一X射线 anode cathode
X-ray tube (p.48 of textbook) anode cathode