High-Order Lowpass Filters Using DVCC Elements

Special cells using a differential voltage current conveyor are presented. The use of these cells for high-order lowpass filter design is described. The filters can be designed to operate in different modes

Study of Adjustable Gains for Control of Oscillation Frequency and Oscillation Condition in 3R-2C Oscillator

An idea of adjustable gain in order to obtain controllable features is very useful for design of tuneable oscillators. Several active elements with adjustable properties (current and voltage gain) are discussed in this paper. Three modified oscillator conceptions that are quite simple, directly electronically adjustable, providing independent control of oscillation condition and frequency were designed. Positive and negative aspects of presented method of control are discussed. Expected assumptions of adjustability are verified experimentally on one of the presented solution

Trace element evidence for the origin of ocean island basalts : an example from the Austral Islands (French Polynesia)

Cet article présente une étude géochimique des roches magmatiques des Iles Australes. La présence et la distribution d'éléments en trace incompatibles indiquent que ces laves dérivent d'une source magmatique hétérogène. Comme le montrent les données isotopiques, ces hétérogénéités sont à attribuer à un mélange entre le manteau supérieur et une croûte océanique en subduction qui, auparavant, avait été la source d'un magma tholeiitiqu

Subducted and recycled lithosphere as the mantle source of ocean island basalts from southern Polynesia, central Pacific

L'étude géochimique et pétrographique des basaltes des archipels volcaniques de la Polynésie Française montre que ces roches dérivent d'une lithosphère ancienne ayant subi une subduction et un recyclage. La composition chimique et isotopique des basaltes montre l'existence d'hétérogénéités géochimiques pour la source magmatique : elles s'expliquent par un mélange de la croûte océanique avec une péridotite résiduelle

Discharges of past flood events based on historical river profiles

International audienceThis paper presents a case study to estimate peak discharges of extreme flood events of Neckar River in south-western Germany during the 19th century. It was carried out within the BMBF research project RIMAX (Risk Management of Extreme Flood Events). The discharge estimations were made for the flood events of 1824 and 1882 based on historical cross profiles. The 1-D model Hydrologic Engineering Centers River Analysis System (HEC-RAS) was applied with different roughness coefficients. The results are compared (i) with contemporary historical calculations and (ii) in the case of a flood event in 1824 with the discharge simulation by the water balance model LARSIM (Large Area Runoff Simulation Model). These calculations are matched by the HEC-RAS simulation based on the standard roughness coefficients

Geochemistry of Ordovician volcanic rocks of the Tetagouche Group of southwestern New Brunswick

The Lower to Middle Ordovician volcanic suite of the Tetagouche Group from the southwestern part of the Miramichi Terrane in the Woodstock-Meductic area in southwestern New Brunswick is composed of a bimodal basalt-rhyolite association. The basaltshave calc-alkalic characteristics and were emplaced on the continental crust in a volcanic arc or back-arc environment. The rhyolites were probably derived by melting of an amphibolite-facies crust. The basalts differ from those of the Tetagouche Group from the Bathurst area which include within-plate basalts and MORB. However, they both may be part of a single Ordovician arc-back-arc system. RÉSUMÉ Le cortege volcanique du Groupe de Tetagouche (Ordovicien médian à inférieur) dans la portion sud-ouest de la Lanière de Miramichi (région de Woodstock-Meductic, sud-ouest du Nouveau-Brunswick) se compose d'une association bimodèle de basalte et rhyolite. Les basaltes présentent des caractéres calco-alcalins et ils se sont mis en place sur la croûte continentale dans un milieu d'arc insulaire ou de rétro-arc. Les rhyolites proviennent probablement de la fonte d'une croûte de faciès à amphibolites. Les basaltes différent de ceux du Groupe de Tetagouche dans la région de Bathurst, qui comprennent des basaltes intra-plaques et des MORB, quoique tous deux puissent faire partie d'un système arc:rétro-arc ordovicien unique. [Traduit par le journal

Full characterization of vibrational coherence in a porphyrin chromophore by two-dimensional electronic spectroscopy

In this work we present experimental and calculated two-dimensional electronic spectra for a 5,15-bisalkynyl porphyrin chromophore. The lowest energy electronic Qy transition couples mainly to a single 380 cm–1 vibrational mode. The two-dimensional electronic spectra reveal diagonal and cross peaks which oscillate as a function of population time. We analyze both the amplitude and phase distribution of this main vibronic transition as a function of excitation and detection frequencies. Even though Feynman diagrams provide a good indication of where the amplitude of the oscillating components are located in the excitation-detection plane, other factors also affect this distribution. Specifically, the oscillation corresponding to each Feynman diagram is expected to have a phase that is a function of excitation and detection frequencies. Therefore, the overall phase of the experimentally observed oscillation will reflect this phase dependence. Another consequence is that the overall oscillation amplitude can show interference patterns resulting from overlapping contributions from neighboring Feynman diagrams. These observations are consistently reproduced through simulations based on third order perturbation theory coupled to a spectral density described by a Brownian oscillator model

Time evolution of stimulated Raman scattering and two-plasmon decay at laser intensities relevant for shock ignition in a hot plasma

Laser–plasma interaction (LPI) at intensities 1015–1016 W cm2 is dominated by parametric instabilities which can be responsible for a significant amount of non-collisional absorption and generate large fluxes of high-energy nonthermal electrons. Such a regime is of paramount importance for inertial confinement fusion (ICF) and in particular for the shock ignition scheme. In this paper we report on an experiment carried out at the Prague Asterix Laser System (PALS) facility to investigate the extent and time history of stimulated Raman scattering (SRS) and two-plasmon decay (TPD) instabilities, driven by the interaction of an infrared laser pulse at an intensity 1:2 1016 W cm2 with a 100 mm scalelength plasma produced from irradiation of a flat plastic target. The laser pulse duration (300 ps) and the high value of plasma temperature (4 keV) expected from hydrodynamic simulations make these results interesting for a deeper understanding of LPI in shock ignition conditions. Experimental results show that absolute TPD/SRS, driven at a quarter of the critical density, and convective SRS, driven at lower plasma densities, are well separated in time, with absolute instabilities driven at early times of interaction and convective backward SRS emerging at the laser peak and persisting all over the tail of the pulse. Side-scattering SRS, driven at low plasma densities, is also clearly observed. Experimental results are compared to fully kinetic large-scale, two-dimensional simulations. Particle-in-cell results, beyond reproducing the framework delineated by the experimental measurements, reveal the importance of filamentation instability in ruling the onset of SRS and stimulated Brillouin scattering instabilities and confirm the crucial role of collisionless absorption in the LPI energy balance

Review: McMULLIN, Irene. \u3ci\u3eTime and the Shared World: Heidegger on Social Relations\u3c/i\u3e

According to McMullin, injustice is, for Heidegger, the insistence on my time ... my now. Because the social and justice are themes of the book, a reader might expect some discussion of the political dimension of human life; but there is no reference to the political, no discussion of the significance of the hero, and no reference to the distinction of the social and the communal (at the cost of the social ) that Heidegger makes toward the end of Being and Time