A ferroelectric capacitor is connected to a properly chosen a. c. voltage generator, and heated nearly to the Curie point by the dielectric loss. Such an element has an ability to stabilize its own temperature automatically, thus its electrical properties are also stabilized. Such a device, which is called TANDEL here, has been developed and applied for several purposes such as electrometric devices, measurement of small velocities or flowing rate, nonlinear piezoelectric pickups, and modulators.
In electrophotographic powder development, a simple model for the toner layer was pre-sented. Using this model, the surface potential of the toner layer was derived. Combining this toner layer model and the model for magnetic brush development presented by R. M. Schaffert, the electric field in the developing space which determines the maximum toner quantity obtained by development was computed. Equations were derived expressing the fully developed toner quantity as a function of the surface potential of the dielectric layer. Experiments were done in order to obtain some constants and to confirm the equations. Experimental results show that toner charge varies according to the toner content of the developer. The decay of surface charge by contact of conductive carriers at development was also taken into account. Experimental results were consistent with these equations.
Piezoelectricity is observed in films of poly (vinylidene fluoride) (PVF2), poly (vinyl fluoride), poly (vinyl chloride), polycarbonate and nylon 11 when they are elongated and polarized by a static field. The largest value of g31, and d31 found in PVF2 films were 150 millivolts/gram cm and 20×10-8cgs esu respectively. The piezoelectricity of the polymer films is caused by the electrostriction and the spontaneous polarization due to the poling effect. By a newly developed apparatus, electrostrictive constants, inverse piezoelectric constants and their temperature dependence were measured for the polymer films. The electrostrictive constant γ31T of PVF2 film is about 3.5×10-11cgs esu and several times larger than those of other films. The large piezoelectricity of PVF2 is due to the large value of γ31T. It is suggested that the previously reported shear-type piezoelectricity of the natural polymers are caused also by electrostriction and spontaneous polarization.
A Half-tone plotter has been developed by the authors. This device can represent discrete patterns of continuous-tone on a cathode ray tube in off-line operation with a computer. The beam deflection can he controlled to 212 discrete horizontal and vertical positions. Brightness modulation can be performed by 8 bits. The processing speed is about 20 points per second and the accuracy of the brightness modulation is sufficient for practical use. This device is appropriate for such applications as digital picture processing and synthesis of computer holo-grams. Applications to simulation of spatial filtering and image restoration by computer processing have been represented.
A number of (Bi1-xSbx)2(Te1-ySey)3 compounds were prepared from melts of stoichiometric composition by the quenched technique. Thermal conductivity was determined at room temperature by a comparison method, and the lattice thermal conductivity was obtained by using the observed values of the Seebeck coefficient and electrical conductivity which are reported by Yokota etal. in the preceding paper.The lattice thermal conductivity at high temperature is derived by using the Ktemens-Callaway theory. It is assumed that the reciprocal relaxation times depend on the fourth power of phonon frequency ω in the scattering process due tostrain and mass point defects and on ω2 in normal and umklapp process of the three phonon anharmonic scatter. In many compounds, experimental values of the lattice thermal conductivity agree with values calculated from the above theory. It is found that the lattice thermal conductivity is mainly governed by strain scatter rather than mass defect scatter. In the case of the compounds rich in Sb2Se3, experimental values are smaller than those calculated from the above theory. Additional phonon scatter by localized mode of point defects, as discussed by Wagner, is used to explain the experimental data. The experimental values of the lattice thermal conductivity of intrinsic materials are not particularly large relative to that of other compounds. Therefore, it seems that ambipoler diffusion has no effect on thermal conductivities ofintrinsic materials, since capture centers of electron and hole are considered to exist in those compounds.
Continuum emission coefficient in absolute units was measured for anargon arc plasma operating at about 1 atmospheric pressure and the ξ-factor, which relates the semi-classical theory of continuum emission to quantum-mechanical one, was studied as for its dependence on wavelength. Assuming ξ=2.3 at 4, 315 Å, 9, 800 K was obtained for the temperature on the arc axis, from which ξas a function of wavelength (3, 875_??_5, 000 Å) was derived. Results are in fairly good agreement with that of Schlüter's experiment and that of Wende's.