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In the present research, the effect of variations of the electron beam voltage on the output power is studied. In order to develop the study, this problem was investigated at different frequencies, which are the products of nonlinear behavior of the traveling wave tube (TWT) in response to the input frequency. Moreover, for a more realistic understanding, the tubes were considered with two linear and nonlinear responses to the input frequency. The TWT output power was calculated in linear and nonlinear modes, at different frequencies using the numerical solution of the mathematical equations of the Lagrangian model. Then, the output power in terms of distance and beam voltage in different frequencies was plotted and compared. The results revealed that the effects of variations of voltage on the output power were more proper in a singlemode TWT in comparison with a multimode one.

The electrical conductivity (σ), ultrasonic velocity (U), density (ρ) and viscosity (η) have been measured for the aqueous potassium chloride solutions at different temperatures and at frequency 4 MHz for different concentration of KCl. The experimental data's have been used for study of the molecular interaction in the different solutions using different parameters such as adiabatic compressibility, free length, acoustic impedance and relaxation time. Variation in the above parameters for the different solutions at different temperature is indicative of the nature of interaction between them.

Abstract:The ultrasonic velocity, density and viscosity have been measured for ternary mixture of N, N dimethylformamide (DMF), cyclohexane and pyridine at different frequencies 2 MHz, 4 MHz and 6 MHz but at constant temperature 318 K. These experimental data's have been used to estimate the parameters such as adiabatic compressibility (β), intermolecular free length (L f ), Gibbs' free energy (∆G), free volume (V f ), specific acoustic impedance (Z) and absorption coefficient (α/f 2 ) for the mixture. The excess values of these parameters are also evaluated and the molecular associations in the mixture are discussed.