Search results for "tunne"

Subglacial to proglacial depositional environments in an Ordovician glacial tunnel valley, Alnif, Morocco

2013

Abstract This paper presents the sedimentary analysis of an exceptional Ordovician glacial tunnel valley in the eastern part of the Anti-Atlas. The valley infill comprises two major glacial erosion surfaces (striated pavements) each overlain by a fining-upward glacial unit. These units are composed of five distinct facies associations, recording the evolution from subglacial to proglacial environments, and an additional sixth facies association, overtopping the tunnel valley infill, and associated with post-glacial environments. The tunnel valley infill also records a transitional environment between the subglacial and proglacial settings, which is compared with the Antarctic ice-sheet marg…

Does porewater or meltwater control tunnel valley genesis? Case studies from the Hirnantian of Morocco.

2015

18 pages; International audience; Several Ordovician tunnel valleys are exposed in the Moroccan Anti-Atlas Mountains, including the Alnif and the Foum Larjamme tunnel valleys, located 150 km away from each other. Sedimentological and deformational analyses of these two glacial troughs reveal that differing processes lead to their formations.The Alnif tunnel valley contains numerous deformation structures within sediments both below and above the main glacial erosion contact surface. Ball-structures and clastic dykes occur within preglacial sediments down to 35 m below glacial incisions while overlying glacial sediments contain fluted surfaces, clastic dykes, dewatering structures, folds and…

Stark ionization of atoms and molecules within density functional resonance theory

2013

We show that the energetics and lifetimes of resonances of finite systems under an external electric field can be captured by Kohn–Sham density functional theory (DFT) within the formalism of uniform complex scaling. Properties of resonances are calculated self-consistently in terms of complex densities, potentials, and wave functions using adapted versions of the known algorithms from DFT. We illustrate this new formalism by calculating ionization rates using the complex-scaled local density approximation and exact exchange. We consider a variety of atoms (H, He, Li, and Be) as well as the H2 molecule. Extensions are briefly discussed.

Supramolecular self-assembly on the B-Si(111)-(√3x√3) R30° surface: From single molecules to multicomponent networks

2017

Abstract Understanding the physical and chemical processes in which local interactions lead to ordered structures is of particular relevance to the realization of supramolecular architectures on surfaces. While spectacular patterns have been demonstrated on metal surfaces, there have been fewer studies of the spontaneous organization of supramolecular networks on semiconductor surfaces, where the formation of covalent bonds between organics and adatoms usually hamper the diffusion of molecules and their subsequent interactions with each other. However, the saturation of the dangling bonds at a semiconductor surface is known to make them inert and offers a unique way for the engineering of m…

NUMERICAL ANALYSIS OF AN ALTERNATIVE VENTILATION SYSTEM AND COMPARISON WITH TRADITIONAL ONE FOR BOTH FULL AND REDUCED-SCALE ROAD TUNNEL

Local tunneling study of three-dimensional order parameter in the pi band of Al-doped MgB2 single crystals

2007

We have performed local tunneling spectroscopy on high quality Mg$_{1-x}$Al$_x$B$_2$ single crystals by means of Variable Temperature Scanning Tunneling Spectroscopy (STS) in magnetic field up to 3 Tesla. Single gap conductance spectra due to c-axis tunneling were extensively measured, probing different amplitudes of the three-dimensional $\Delta_\pi$ as a function of Al content. Temperature and magnetic field dependences of the conductance spectra were studied in S-I-N configuration: the effect of the doping resulted in a monotonous reduction of the locally measured $T_C$ down to 24K for x=0.2. On the other hand, we have found that the gap amplitude shows a maximum value $\Delta_\pi= 2.3$ …

Virolaiset ikivanhaa hallitsijakansaa: Virolaisjohtajien puheita kansallisen identiteetin muokkaamiseksi 1930-luvulla

2012

Artikkelissa tarkastellaan Viroa melko itsevaltaisesti 1930-luvulla hallinneiden Konstantin Pätsin, armeijan ylipäällikön Johan Laidonerin ja suurimman osan Pätsin ajasta pääministerin virkaa toimittaneen Kaarel Eenpalun puheiden menneisyyspolitiikkaa. Tutkitut puheet käsittelivät Viron historiaa ennen 1800-luvun puoliväliin sijoittunutta niin sanottua kansallista heräämisaikaa. Aika muinaisen vapausajan lopusta kansalliseen heräämisaikaan on nähty kansallisesti passiivisena ajanjaksona, jolloin virolaisilla ei ollut varsinaista kansallistunnetta. Valtion johtajat pyrkivät puheillaan muinaisesta vapausajasta ja 700- vuotisesta miehitysajasta muuttamaan tätä käsitystä. Artikkelissa puheista …

Correction: “On-the-fly” coupled cluster path-integral molecular dynamics: impact of nuclear quantum effects on the protonated water dimer

2015

We present an accelerated ab initio path-integral molecular dynamics technique, where the interatomic forces are calculated “on-the-fly” by accurate coupled cluster electronic structure calculations. In this way not only dynamic electron correlation, but also the harmonic and anharmonic zero-point energy, as well as tunneling effects are explicitly taken into account. This method thus allows for very precise finite temperature quantum molecular dynamics simulations. The predictive power of this novel approach is illustrated on the example of the protonated water dimer, where the impact of nuclear quantum effects on its structure and the 1H magnetic shielding tensor are discussed in detail.

Total ionizing dose (TID) evaluation of magnetic tunnel junction (MTJ) current sensors

2015

Abstract The paper shows an experimental study to know the behaviour of tunnel magnetoresistive effect-based current sensors configured in a Wheatstone bridge in response to irradiation. In particular the sensitivity, hysteresis, output offset voltage and input resistance are discussed when the sensors are submitted to a total irradiation dose of 43 krad with 36 krad/h dose rate. The same electrical parameters were studied subsequently once the irradiated sensors were submitted to an 80 °C annealing process. The studied TMR sensors are applied in a switched-mode power converter for space application.

Electrical Characterization of a Magnetic Tunnel Junction Current Sensor for Industrial Applications

2012

The objective of the work was the design of a Wheatstone bridge current sensor using MTJ as magnetoresistive elements. Each one of the four resistances of the bridge consists on 360 MTJ single elements connected in series for improved electrical robustness. A printed circuit board (PCB) was designed with a U-shaped copper trace placed under the PCB maintaining a 1.1 mm separation distance between sensor and trace. A 160% of tunnel magnetoresistance effect in the single junction and a 120% in its corresponding series elements connection has been achieved with a sensitivity of 9.2 Ω/Oe in a 65 Oe linear range. The DC sensor sensitivity in response to an external DC current sweeps of ±10, ±20,…