Asymmetric Triangle Research Articles

Simulation of pseudostationary radical polymerization, 1. Chain‐length distributions for arbitrary initiation profiles

AbstractA procedure is developed which allows to treat arbitrary periodic initiation profiles (asymmetric and symmetric triangle profiles, sinusoidal profiles, Gaussian profiles etc.) in pseudostationary radical polymerization. Using an iterative method these profiles are transformed into the (likewise periodic) radical profiles and into the chain‐length distributions of the resulting polymer in case of termination by disproportionation. These distributions are analysed for the position of their inflection points which may be used for experimental determination of the elementary rate constant of chain propagation kp. It turned out that for all profiles that have at least one discontinuity (e.g. asymmetric triangle profiles) the position of the point of inflection is a correct measure of kp for a conveniently wide range of experimental parameters. In case of profiles without discontinuity (symmetric triangle profiles, sinusoidal and Gaussian profiles) the position of the inflection point is shifted to lower values which means that the kp values determined on this basis will be a little too small. In most cases, however, the error introduced by this fact will not exceed the overall error of the experiment so that in practice the method of determining kp in pseudostationary polymerization is not restricted to those profiles which exhibit discontinuities.

Special complex open-cavity and low-magnetic-field high-power gyrotron

A theory is proposed for the special complex cavity; it is in the form of a single resonant circuit having a TE/sub 0n/ from or to TE/sub 0,n+p/ mode converter and it features excellent mode selectivity, high power capability, and an asymmetric triangle profile of the RF field that is favourable to efficient operation for a 35-GHz second-harmonic gyromonotron employing this complex cavity with TE/sub 03/ mode output are numerically illustrated and experimentally demonstrated. Power as high as 200 kW and efficiency as high as 30% have been obtained. These experimental results are record values for a gyrotron operating at the second-harmonic millimeter wavelength. Implications of the single-resonant complex cavity for the fundamental harmonic and third-harmonic high-average-power gyrotron design are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Intracardiac Electrograms and Sensing Test Signals: Electrophysiological, Physical, and Technical Considerations

Until now, the characterization of intracardiac electrograms was carried out mainly in the frequency domain by which filtering and sensitivity testing was decidingly influenced. The typical structure of the intracardiac electrogram derived with unipolar electrodes that is normally responsible for synchronization can be explained theoretically by assuming two dipoles perpendicular to each other moving along with an excitation wave. An abstraction of this typical structure yields, as a sensitivity test signal, an asymmetric triangle with a 4-ms decay time and a 16-ms rise time. A correlation of different test signals and real heart signals applied to 16 different pacemakers demonstrates that the proposed test signal is superior to all others known so far.

A method for the synthesis of microwave open resonators

Abstract In this paper, based on several mathematical and physical considerations, the conditions which must hold for the field profile function of a microwave open resonator are derived. These conditions are important for finding the cavity geometry for a given field profile in an open resonator. The synthesis of microwave open resonators is developed here. The method can be used to deduce the cavity geometry from the given cavity field profile at a resonance frequency and cavity Q-value for a mode. As an example, this method is applied to the asymmetric triangle field profile. The basic procedure for designing a cavity structure of this kind is proposed. This synthesis method is simple, straightforward and suited to extensive applications.