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In two separate studies, a correlation has been observed between the myoelectric signals (MESs) present in neck muscles during speech and the acoustic waveform. In the first study, five experiments were conducted using a 17-word vocabulary. The application of maximum likelihood pattern recognition to the averaged myoelectric signal produced recognition accuracies as high as 98% for a two-word set...
Although it is well known that divergent electric fields, such as produced by the needle-plane geometry, will generate tree-like breakdown channels that, in time, penetrate the dielectric, such channels are not seen under uniform field conditions. Further, it is also known that the electrical treeing process is accompanied by internal discharges which are readily detected by electrical and optical...
In this paper we shall survey measurements of dielectric properties of materials with respect to precision. We shall consider both optimum and extreme conditions, and try to indicate the source and magnitude of errors. To better acquaint conferees (and readers) with the National Bureau of Standards, we shall choose a disproportionate share of the examples from work done or in progress at NBS.
In 1960 Gubkin1 published an electrostatic theory of piezoelectricity which did not involve the microscopic structure of the electret. This approach would seem to be a good description of the phenomenon of piezoelectricity in polymer materials, many of which are partially or completely amorphous. We applied Gubkin's model to a specific set of experimental conditions, which resulted in some simplifications...
A cell has been designed and built for measurement of the dielectric constant and dissipation factor of thin films. The principle employed is the two-fluid, three-terminal scheme, 1,2, 3 adapted to thin film measurements. Measurements of dielectric constant, dissipation factor and thickness can be obtained on films ranging from about 250 μm (10 mil) down to 1 μm (0. 04 mil). Agreement is in general...
Accurate measurements of dielectric properties of materials by the three-terminal air-gap method require accurate knowledge of the area of the electrodes. The expression giving the dielectric constant can be put in the form equation (1) where equation Equation (1) can be solved for A, giving equation The two fluid method enables us to measure the dielectric constant of a specimen without knowledge...
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