Crystals and their uses rom the Bronze Age Crystals for bone replacement Crystals and their defects to the "golden age of stee in metallurgy 000 Studies of the chemical composition of bones and Metallurgy is the study of metals,intermetallic tooth enamel were quite perplexing for the first compounds and mixtures thereof known as alloys. researchers.These chemical compounds are very The first evidence of human metallurgy dates from reactive nano-crystals known as apatites.By means the 5th and 6th centuries BC.They have numerous of artificial biomineralization,Man has been able to uses ranging from steel in construction to complex create crystalline prostheses which imitate alloys used in modern jet engines to coatings nature. that confer corrosion resistance.It is often the defects in metals and alloys that determine their Crystals for pharmacetical applications very useful electrical and mechanical properties. The same molecule can crystallise in different Liquid crystals！! forms while presenting the same chemical characteristics in solution.This polymorphism A liquid crystal is a phase between the liquid and results from a different arrangement of molecules. the solid state:it flows like a liquid but has the In pharmacy,It is important to control the shape properties of a solid.The molecules ofaliqid and size of the crystals that contain the active crystal are highly elongated and have a tendency to nematique cholesterique molecule of the medicine,because these line up like matches in a box.They owe their name Cristaux liquides Gecrces friedel parameters may influence the dissolution rate to their optical properties which are similar to and thus have an effect on the effectiveness of the those of regular crystals. medicine.. dbddho99d LPateur-Stuasboug Hipprosthesis ecol.EoedeMnes快Sn-fiene ow to mend bones? Polymor ofsparagine sthemdiunaopere t mavbe im emdtrtto匹fsoihectton dhwtho