INTRODUCTION AND OBJECTIVES Vocal fatigue is one of the most common voice symptoms. It usually refers to the sensation of vocal tiredness after a long period of speaking or singing. The purpose of this study was to compare the acoustic characteristics of the voice before and after a long period of voice use in a group of radio broadcasters. METHODS Eight radio broadcasters with normal voices ...

A theoretical spectroscopic analysis of a microwave driven superconducting charge qubit Cooper-pair box coupled to an RLC oscillator model is performed. By treating the oscillator as a probe through the backreaction effect of the qubit on the oscillator circuit, we extract frequency splitting features analogous to the AutlerTownes effect from quantum optics, thereby extending the analogies betw...

Traveling Wave Tubes (TWTs) consist of different elements. The most important element of TWT is the RF circuit. RF circuits in helix TWTs need a dielectric support to hold the helix; this support also has an effect in electromagnetic properties of RF circuits. A novel dielectric support is proposed to reduce the second harmonic of helix TWTs. The dielectric support in this structure consists of...

A model of auditory grouping is described in which auditory attention plays a key role. The model is based upon an oscillatory correlation framework, in which neural oscillators representing a single perceptual stream are synchronised, and are desynchronised from oscillators representing other streams. The model suggests a mechanism by which attention can be directed to the high or low tones in...

The paper is devoted to the solution of the inverse boundary problem for the heat equation. Let Ω be a connected bounded domain in R n (n ≥ 2) with C l (l ≥ 2) boundary Γ. Consider the mixed problem for the heat equation (1.1)        (ρ(x)∂ t − −)u f (t, x) = 0 in (0, +∞) × Ω, u f (t, x) = f (t, x) o n(0 , +∞) × Γ, u f (0, x) = 0 on Ω. The density ρ(x) is a C l+σ , 0 < σ < 1, function on...

In this paper, we study the Lehmer’s type congruences for lacunary harmonic sums.

Surface finishes are used to preserve and promote solderability of exposed copper metallization on printed wiring boards. While in the best of worlds, the solder used in assembly should dictate the solder interconnect reliability, surface finishes are known to have an effect. The effect of surface finishes on solder interconnect reliability can be particularly strong under high strain rate load...

At the most fundamental level, main rotor loading noise is caused by the harmonically-varying aerodynamic loads (acoustic pressures) exerted by the rotating blades on the air. Rotorcraft main rotor noise is therefore, in principle, a function of rotor control inputs, and thus the forces and moments required to achieve steady, or “trim”, flight equilibrium. In certain flight conditions, the ensu...