“piezoelectric effect”的概念、定义、翻译、参考文献-科学参考

piezoelectric effect

Physics

The generation of a potential difference across the opposite faces of certain nonconducting crystals (piezoelectric crystals) as a result of the application of mechanical stress between these faces. The electric polarization (see dielectric) produced is proportional to the stress and the direction of the polarization reverses if the stress changes from compression to tension. The reverse piezoelectric effect is the opposite phenomenon: if the opposite faces of a piezoelectric crystal are subjected to a potential difference, the crystal changes its shape. Rochelle salt and quartz are the most frequently used piezoelectric materials. While Rochelle salt produces the greater polarization for a given stress, quartz is more widely used as its crystals have greater strength and are stable at temperatures in excess of 100°C.

If a quartz plate is subjected to an alternating electric field, the reverse piezoelectric effect causes it to expand and contract at the field frequency. If this field frequency is made to coincide with the natural elastic frequency of the crystal, the plate resonates; the direct piezoelectric effect then augments the applied electric field. This is the basis of the crystal oscillator and the quartz clock. See also crystal microphone; crystal pick-up.

Electronics and Electrical Engineering

An effect that occurs when certain materials are subjected to mechanical stress. A dielectric polarization is set up in the crystal and the faces of the crystal became electrically charged. The polarity of the charges reverses if the compression is changed to tension. Conversely, an electric field applied across the material causes it to contract or expand according to the sign of the electric field.
The piezoelectric effect is reversible with an approximately linear relation between deformation and electric field strength. The piezoelectric strain constant, d, is defined as
$d_{i, k} = \frac{δ e_{k}}{δ E_{i}}$
where δe_k is the incremental stress and δE_i the change in electric field strength along defined axes in the crystal (i ≡ x, y, z and k ≡ xx, yy, zz, yz, zx, xy).
The piezoelectric effect is observed in all ferroelectric crystals and in nonferroelectric crystals that are asymmetric and have one or more polar axes. The magnitude of the piezoelectric effect depends on the direction of the stress relative to the crystal axes. The maximum effect is obtained when the electrical and mechanical stresses are applied along the X-axis (the electric axis) and the Y-axis (the mechanical axis), respectively. The third major axis of a piezoelectric crystal is the Z-axis (the optical axis).
The piezoelectric effect is important because it couples electrical and mechanical energy and thus has many applications for electromechanical transducers.

单词	piezoelectric effect
释义	piezoelectric effect Physics The generation of a potential difference across the opposite faces of certain nonconducting crystals (piezoelectric crystals) as a result of the application of mechanical stress between these faces. The electric polarization (see dielectric) produced is proportional to the stress and the direction of the polarization reverses if the stress changes from compression to tension. The reverse piezoelectric effect is the opposite phenomenon: if the opposite faces of a piezoelectric crystal are subjected to a potential difference, the crystal changes its shape. Rochelle salt and quartz are the most frequently used piezoelectric materials. While Rochelle salt produces the greater polarization for a given stress, quartz is more widely used as its crystals have greater strength and are stable at temperatures in excess of 100°C. If a quartz plate is subjected to an alternating electric field, the reverse piezoelectric effect causes it to expand and contract at the field frequency. If this field frequency is made to coincide with the natural elastic frequency of the crystal, the plate resonates; the direct piezoelectric effect then augments the applied electric field. This is the basis of the crystal oscillator and the quartz clock. See also crystal microphone; crystal pick-up. Electronics and Electrical Engineering An effect that occurs when certain materials are subjected to mechanical stress. A dielectric polarization is set up in the crystal and the faces of the crystal became electrically charged. The polarity of the charges reverses if the compression is changed to tension. Conversely, an electric field applied across the material causes it to contract or expand according to the sign of the electric field. The piezoelectric effect is reversible with an approximately linear relation between deformation and electric field strength. The piezoelectric strain constant, d, is defined as $d_{i, k} = \frac{δ e_{k}}{δ E_{i}}$ where δe_k is the incremental stress and δE_i the change in electric field strength along defined axes in the crystal (i ≡ x, y, z and k ≡ xx, yy, zz, yz, zx, xy). The piezoelectric effect is observed in all ferroelectric crystals and in nonferroelectric crystals that are asymmetric and have one or more polar axes. The magnitude of the piezoelectric effect depends on the direction of the stress relative to the crystal axes. The maximum effect is obtained when the electrical and mechanical stresses are applied along the X-axis (the electric axis) and the Y-axis (the mechanical axis), respectively. The third major axis of a piezoelectric crystal is the Z-axis (the optical axis). The piezoelectric effect is important because it couples electrical and mechanical energy and thus has many applications for electromechanical transducers.
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