The electrical characteristics of high-mobility, two-dimensional electron gas (2DEG) systems, such as GaAs quantum wells, have been well-studied at low frequencies and in extreme conditions of high magnetic fields and ultralow temperatures. While highfrequency excitations of 2DEGs have been examined to some extent from microwave to terahertz (THz) frequencies, a fundamental understanding of the...

The changes in the male voice in relation to the biological characteristics of puberty were assessed longitudinally in 26 boys. Speaking and singing fundamental frequencies were analysed in relation to the Tanner staging of puberty, saliva testosterone levels, and the Cooksey classification of voice analysis. There were abrupt changes in voice characteristics between Tanner stages G3 and G4 and...

1. Concurrent resting and postural tremors of patients with idiopathic Parkinson's disease were monitored using transducers responding to angular velocity of rotation. Spectra and correlation functions were calculated for each pair of records. 2. When concurrent tremor spectra share indistinguishable fundamental frequencies, have statistically significant peaks in their coherence spectra at tho...

For polyatomic molecules, n-mode coupling representations of the quartic force field (nMR-QFF) are presented, which include terms up to n normal coordinate couplings in a fourth-order polynomial potential energy function. The computational scheme to evaluate third-and fourth-order derivatives by finite differentiations of the energy is fully described. The code to generate the nMR-QFF has been ...

Harmonics have much significance in music. A musical note has three characteristics. 1 Pitch (or frequency) 2 Loudness 3 Quality (or tone). Quality is the audible difference heard between two musical notes of the same pitch and loudness. Hence, a piano based C-note does not sound the same as a C-note played on a guitar, due to the existence of harmonic frequencies. The same note from various in...

Differences in vowel formants in bass and tenor singers, as well as the perception of vowels synthesised at different fundamental frequencies predict that in a group of male or female speakers exhibiting a sufficiently wide range of average fundamental frequencies, there will be a positive correlation between the speakers’ average f0 and the dimensions of their acoustic vowel spaces. This hypot...

In this paper, changes in acoustic characteristic of young children speech are investigated as a function of age. We examined fundamental frequency, formant frequencies and vowel durations of ten monophtongal vowels from American-English speaking children, age groups 3 to 6. In this study, we also examined the vowel pronunciation variability of young-aged children. The results show that prescho...

Many modern theories predict that the fundamental constants depend on time, position or the local density of matter. Here we develop a spectroscopic method for pulsed beams of cold molecules, and use it to measure the frequencies of microwave transitions in CH with accuracy down to 3 Hz. By comparing these frequencies with those measured from sources of CH in the Milky Way, we test the hypothes...

Using inverse filtering, voice source characteristics related to vocal £old adductory force, and the first formant frequency, are analyzed in six professional male singers and six male nonsingers repeatedly phonating the syllable /pae:/ in loud and soft phonation at different fundamental frequencies throughout the subjects' ranges. For each voice sample, inverse filtered air flow was recorded a...