We present an alternative method for measuring ultrashort extreme-ultraviolet pulses that can be synchronized with an intense infrared pulse. The method, based on photoionization of a target atom by the extremeultraviolet pulse in the presence of the infrared pulse, has a potential accuracy of close to 1 fs and is susceptible to single-shot operation. It is demonstrated on harmonic 15 of a tita...

We present a monolithic passively Q-switched microchip laser generating 200 ps pulses at a wavelength of 1064 nm with a repetition rate of up to 2 MHz. While maintaining transversal and longitudinal single-mode operation, the pulse energy can be changed from 130 nJ to 400 nJ by varying the pump conditions of the laser. To the best of our knowledge, the repetition rate of 2 MHz is by far the hig...

In this paper we show that every real-time system speciied in a certain subset of Duration Calculus 24] can be decomposed into an untimed system communicating with suitable timers. Both asynchronous and synchronous communication are considered.

The spin dynamics in Ni is studied by an exact diagonalization method on the ultrafast time scale. It is shown that the femtosecond relaxation of the magneto-optical response results from exchange interaction and spin-orbit coupling. Each of the two mechanisms affects the relaxation process differently. We find that the intrinsic spin dynamics occurs during about 10 fs while extrinsic effects s...

We present a complete axiomatisation of the operator of projection onto state in the Duration Calculus (DC ) relative to validity in DC without extending constructs. Projection onto state was introduced and studied extensively in our earlier works. We first establish the completeness of a system of axioms and proof rules for the operator relative to validity in the extension of DC by neighbourh...

Among the possible approaches for expressing real-time problems with the B method, two are dominant : the use of the usual B mechanisms to define temporal constraints on one hand, and extending B through another formalism more adapted to the real-time context. We define here a possible temporal semantic for B, by using a temporal logic (the duration calculus), and we illustrate how this extensi...

This paper assesses hypothesis that sufficient sleep duration and proper circadian rhythms during the early stages of life are indispensable to a successful life. Successful life was defined according to the famous cohort studies of Mischel's and Dunedin. To assess the hypothesis, neuronal elements presumably affecting early daily habits and successful life are reviewed. The effect of sufficien...