Oxygen(O) Sulfur() Selenium(Se) Tellurium(Te) Polonium(Po) 也称为成矿元素(ore--forming elements), because many metal ores are oxides and sulfides Electron configuration: ns2npt
uiz2(11/7/03)-sar esti。ns rse and fiber-directi moduli for a transversely isotropic composite lamina 2. Plot and explain the variation of fiber-direction strength of a unidirectionally-reinforced lamina as a function of fib fraction