피에조
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Transcript of 피에조
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Chapter 1
1. (Principles of Piezoelectricity)
1. (Definition of Piezoelectricity)
piezo pressure piezoelectricity pressure electricity .
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7 crystal systems 32 (point groups) . 32
21 (non-centrosymmetry) 20
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Fig.
(G. H. Haertling, Ferroelectric Ceramics, J. Am. Ceram. Soc., 1999)
(strain/stress) (field/charge)
(polarization) . , ,
. (IEEE
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Standard on Piezoelectricity, 1988) .
Sij = sEijklTkl + dijmEm,
Dn = dnklTkl + TmnEm,
where, Sij, Tkl are mechanical strain and stress tensors,
sEijkl is compliance when electric field is constant,
dijm, dnkl are piezoelectric charge constant tensors,
Tmn is permittivity when the mechanical stress is constant,
Dn, Em are the electric displacement and field vectors.
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Fig. PZT
(-) (+) (-) /(+) . 180o (/)
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(a) (b) (c)
Fig. (polarization)
(a) , (b) , (c) ,
(d), (e) , (f) /
Fig. (Piezoelectric effects)
(a) (b) (a) , (c) (b) . (d) (a)
, (e) (d)
. (f) (d), (e)
/ .