Kontrola akustičnom metodom raspadanja stijena pri rotacionom bušenju

The contribution describes the technical and algorithmic solution of the optimization of rotary drilling. The global optimization criteria express the minimum specific energy on drilling and the maximum speed of drilling. The article presents the first results of research on the utilization of acoustic methods in indirect measurement of criterion function by optimizing these processes.Rad opisuje tehničko i algoritmičko rješenje optimalizacije rotacionog bušenja. Globalna optimalizacija kriterija izražava minimalnu specifičnu energiju bušenja i maksimalnu brzinu bušenja. Članak predstavlja prve rezultate istraživanja primjene akustičkih metoda u neizravnom mjerenju funkcije kriterija optimaliziranjem tih procesa

Laser plasma density profile modification by ponderomotive force

The plasma density profile modification due to the ponderomotive force is analysed by numerical treatment of a consistent system of hydrodynamical and Maxwell equations in a plane geometry. Reflectance temporal oscillations are proposed as a result of density profile oscillations at the cutoff.La modification du profil de la densité du plasma produite par la force pondéromotrice est analysée par un traitement numérique du système auto-cohérent des équations hydrodynamiques et des équations de Maxwell dans une géométrie plane. On prévoit des oscillations du pouvoir réflecteur en fonction du temps à cause des oscillations du profil de densité au cutoff

Correlations in photon-numbers and integrated intensities in parametric processes involving three optical fields

Two strongly-pumped parametric interactions are simultaneously realized in a single nonlinear crystal in order to generate three strongly correlated optical fields. By combining together the outputs of two of the three detectors measuring intensities of the generated fields, we obtain the joint photocount statistics between the single field and the sum of the other two. We apply a microscopic quantum theory developed earlier to determine the joint photon-number distribution and the joint quasi-distributions of integrated intensities and prove nonclassical nature of the three-mode state. Finally, by performing a conditional measurement on the single field, we obtain a state endowed with a sub-Poissonian statistics, as testified by the analysis of the conditional Fano factor. The role of quantum detection efficiencies in this conditional state-preparation method is discussed in detail

Experimental demonstration of sub-shot-noise intensity correlations in an intense twin beam

Twin-beam states of light produced by spontaneous parametric downconversion are endowed with sub-shot-noise photon-number correlations at any intensity regime. We have demonstrated sub-shot-noise photon-number correlations in a ps-pulsed intense (more than 1000 photons) twin beam by measuring the variance of the difference in the number of photons detected in the two outputs of the crystal. The variance is 3.25 dB below the shot-noise level. Measurements show that detection of sub-shot-noise correlation requires a careful selection of twin coherence areas and that these areas depend on the pump intensity

Experimental demonstration of sub-shot-noise intensity correlations in an intense twin beam

Twin-beam states of light produced by spontaneous parametric downconversion are endowed with sub-shot-noise photon-number correlations at any intensity regime. We have demonstrated sub-shot-noise photon-number correlations in a ps-pulsed intense (more than 1000 photons) twin beam by measuring the variance of the difference in the number of photons detected in the two outputs of the crystal. The variance is 3.25 dB below the shot-noise level. Measurements show that detection of sub-shot-noise correlation requires a careful selection of twin coherence areas and that these areas depend on the pump intensity