Several recent results on the regularity of streamlines beneath a rotational travelling wave, along with the wave profile itself, will be discussed. The survey includes the classical water wave problem in both finite and infinite depth, capillary waves and solitary waves as well. A common assumption in all models to be discussed is the absence of stagnation points.

We show that wave maps φ from two-dimensional Minkowski spaceR to hyperbolic spacesH are globally smooth in time if the initial data is smooth, conditionally on some reasonable claims concerning the local theory of such wave maps, as well as the self-similar and travelling (or stationary solutions); we will address these claims in the sequels [67], [68], [69], [70] to this paper. Following rece...

High-power high-voltage dc power supply has been developed based on series resonant converter technology for a MW class RF amplifier. For low-voltage ripple, an IGBT inverter consisting of 1400 V-600 A devices is drives with a maximum switching frequency of 31.2 kHz. A performance test was carried out using an RF amplifier. We examined this power supply under two different conditions. One was w...

The balanced amplifier is used in applications requiring a better input match than is possible with a single-ended amplifier. While the impedance matching property of the balanced amplifier is well known, its noise behavior appears not to be widely understood. It is shown that the outgoing noise waves at the input and output of a balanced amplifier are uncorrelated even though they originate in...

Weakly nonlinear waves in elastic rods have been studied by many authors. Most studies concentrated on smooth solutions only. However, when waves are of moderate length, non-smooth waves, such as peakons (or solitary shock waves), can arise (see Dai and Huo 2000). For strongly nonlinear waves (not assuming the smallness of the wave amplitude), as far as the authors are aware, only incompressibl...

In this paper the design and a complete characterization of an InP/InGaAs single heterojunction bipolar (SHBT) mm-wave amplifier is described. The circuit is designed for the 60 GHz band allocated for wireless LAN and mobile communications. The amplifier achieves a gain of 20 dB from 50 GHz to 70 GHz. Beside S-parameter noise and gain compression measurements are presented. No comparable HBT am...

We present measurements of the power noise that is due to optical amplification in a laser-diode-pumped Nd:YAG free-space traveling-wave linear amplifier in a master-oscillator-power-amplifier configuration. The quantum noise behavior of the optical amplifier was demonstrated by use of InGaAs photodetectors in a balanced detection configuration, at a total photocurrent of 100 mA and in a freque...

We demonstrate a geometrically inspired technique for computing an Evans function for the linearised operator about a travelling wave in the Fisher/KPP equation. We produce an Evans function which is computable through several orders of magnitude in the spectral parameter and show how such a function can naturally be extended into the continuous spectrum. We conclude with a new proof of stabili...

We study entropy travelling wave solutions for rst order hyperbolic balance laws. Results concerning existence, regularity and asymptotic stability of such solutions are proved for convex uxes and source terms with simple isolated zeros.