The electromechanical coupling coefficient, the
piezoelectric constant, the elastic compliance constant and the
mechanical quality factor for a poly-L-lactic acid (PLLA) plate
elongated to 4 times the original length were determined by a
self-resonant method. k
14=0.064, d
14=9.82×10-12 C/N,
s
44
E
=9.28×10-10 m2/N and Q
m
=30.3 were obtained at room temperature
for a 0° X-cut square plate. It is noted that elongated PLLA
films have no spontaneous polarization, unlike poled polymers
such as poly(vinylidene fluoride) (PVDF), but still have a large
shear piezoelectric constant.
The glycerinated stalk of the peritrich ciliate Vorticella, was treated with various reagents to chemically modify the amino acid residues. The influences of these modifcations on spasmoneme contractility were investigated. First, it was confirmed that the spasmoneme contraction is not inhibited by alteration of SH groups. It was also demonstrated that chemical modification of methionine and tryptophan residues abolishes spasmoneme contractility. The reagents used for chemical modification were N-bromosuccinimide (NBS), chloramine T, and 2-hydroxy-5-nitrobenzyl bromide (HNBB), which abolished spasmoneme contractility at concentrations of 40-50 microM, 200-300 microM, and 4 mM, respectively. These results suggest that, along with Ca2+ binding proteins, there are other as yet to be identified proteins involved in contractility.
Ultrasonic velocities and dielectric constants were measured along different directions on the X-Z plane of a Pb(Zr0.52Ti0.48)O3 ceramic (poling direction is along the Z-axis). A complete set of values of elastic stiffness constants and piezoelectric e- and d-constants have been obtained by the least squares method from the velocities and dielectric constants.
Elastic compliance constants, elastic stiffness constants, electro-mechanical coupling coefficients, mechanical losses and thermal expansion coefficients have been obtained for lanthanum doped lead zirconate-titanate ceramics having composition of (X/65/35) with X=1 to 7.5 (abbreviated to rhombohedral PLZT) over a temperature range including the Curie point and ferroelectric-ferroelectric phase transition point (so-called FE1FE2 point) existing in the rhombohedral ferroelectric phase. All measured constants have definite anomalies at the Curie point but only elastic constants s
33 and c
33 have anomalies at the FE1-FE2 point. Phenomena observed for the rhombohedral PLZT were found much different from those for the tetragonal PLZT and other systems.
By using the strong-field scheme, we have calculated all the reduced matrix elements and the matrix elements of the trigonal crystal field and all the matrix elements of the spinorbit interaction for the d 3 electronic configuration: The complete energy matrix of the d configuration in trigonal Held has been constructed. This matrix has been diagonalized to fit the experimental optical and microwave spectral data of ruby. The calculated results are in good agreement with the experimental data. In particular, the zero-field splitting S of the ground state and the splitting between Ri and R 2 lines agree very well with the experimental results. The assignments of all the energy levels and the rates of change of the levels with respect to various parameters are given. The contributions from various parameters to 6 and the splitting between R\ and R 2 lines are aiso giveji.
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