Modelisation of a circuit microurban integrant a transistor (HBT) by a method iterative with auxiliary sources
In summary, auxiliary sources are modeled by an iterative method, a much more applied aspect to linked with the evolved functions. Which is able to be realized by the association of an active component (transistor HBT) with a passive planar structure, operating in the field of the microwaves.
A new approach for microstrip active antennas using modal F.F.T-algorithm
A full-wave fast wave concept iterative technique is developed to analyze single and stacked microstrip active antennas with arbitrary shape. The wave concept is developed to express the boundary conditions on the radiating surfaces in term of the waves, which are solved using the iterative technique. With the help of the modal FFT-algorithm an efficient code is developed which allows a rapid and accurate characterization of arbitrary shaped antennas embedded in single and multilayered dielectric without the trial functions usually used in the conventional integral method. The time saving factor is about 20 compared to the conventional numerical integral methods. Field distribution and input admittance are derived.
HYPERGOLIC REACTION MECHANISMS OF CATALYTICALLY PROMOTED FUELS WITH ROCKET GRADE HYDROGEN PEROXIDE
Abstract The coupling of the physical and chemical processes controlling the ignition delays (τ ign ) of hypergolic propellants complicates the direct analysis of the transient ignition processes. The transport properties of both the propellants and the ambient gas, and the heat of vaporization and reaction affect τ ign and must be considered experimentally. Furthermore, since hypergolic ignition occurs, by definition, on contact, the mechanics of initial contact and subsequent mixing can affect τ ign and must also be considered. Experimental results from a study of the hypergolic ignition of a catalytically promoted fuel with rocket grade hydrogen peroxide (RGHP) are presented. Statistical analysis of the experimental data was conducted to evaluate the relative effects of RGHP concentration, initial ambient pressure, and the ambient gas on τ ign . At RGHP concentrations of less than 92% in water, stable ignition was difficult to achieve. At sufficiently high Lewis number, an oscillatory ignition process is observed. A phenomenological model comprising mixing, RGHP decomposition, fuel heating and vaporization, and auto-ignition is presented and compared to the experimental results.