Search results for "prece"
showing 10 items of 192 documents
Ferromagnetic gyroscopes for tests of fundamental physics
2020
A ferromagnetic gyroscope (FG) is a ferromagnet whose angular momentum is dominated by electron spin polarization and that will precess under the action of an external torque, such as that due to a magnetic field. Here we model and analyze FG dynamics and sensitivity, focusing on practical schemes for experimental realization. In the case of a freely floating FG, we model the transition from dynamics dominated by libration in relatively high externally applied magnetic fields, to those dominated by precession at relatively low applied fields. Measurement of the libration frequency enables in situ measurement of the magnetic field and a technique to reduce the field below the threshold for w…
Astrochronology of the Valanginian stage from GSSP candidates and hypostratotype.
2013
Valanginian; Astrochronology; Gamma-ray spectrometry; Weissert event; Paraná-Etendeka; International audience; The Valanginian Stage currently displays no radiometric age, which severely hampers palaeoceanographic reconstructions for this time interval. An astrochronology of the Valanginian Stage using the stable 405-kyr eccentricity cycle was performed on biostratigraphically well-calibrated standard sections from the Vocontian Basin (southeastern France). High-resolution gamma-ray spectrometry signals were obtained from orbitally driven marl-limestone alternations from five sections in the basin, and they display the same long-term trends. The spectral analyses present the pervasive recor…
Experimental benchmarking of quantum control in zero-field nuclear magnetic resonance
2017
Zero-field nuclear magnetic resonance (NMR) provides complementary analysis modalities to those of high-field NMR and allows for ultra-high-resolution spectroscopy and measurement of untruncated spin-spin interactions. Unlike for the high-field case, however, universal quantum control -- the ability to perform arbitrary unitary operations -- has not been experimentally demonstrated in zero-field NMR. This is because the Larmor frequency for all spins is identically zero at zero field, making it challenging to individually address different spin species. We realize a composite-pulse technique for arbitrary independent rotations of $^1$H and $^{13}$C spins in a two-spin system. Quantum-inform…
Polarization-driven spin precession of mesospheric sodium atoms
2018
We report experimental results on the first on-sky observation of atomic spin precession of mesospheric sodium driven by polarization modulation of a continuous-wave laser. The magnetic resonance was remotely detected from the ground by observing the enhancement of induced fluorescence when the driving frequency approached the precession frequency of sodium in the mesosphere, between 85 km and 100 km altitude. The experiment was performed at La Palma, and the uncertainty in the measured Larmor frequency ($\approx$260 kHz) corresponded to an error in the geomagnetic field of 0.4 mG. The results are consistent with geomagnetic field models and with the theory of light-atom interaction in the …
Verso una dimensione narrativa delle mappe
2021
Tra il pensiero e la costruzione dell’architettura il disegno ha un ruolo baricentrico per connettere i diversi protagonisti di una realizzazione e per coinvolgere la collettività facendo percepire inedite prospettive. La scrittura si rivela utile per esplicitare ciò che nella grafica è sotteso e per stabilire un ordine nuovo nel ragionamento progettuale. I rapporti fra segni e significati si moltiplicano nei sistemi informativi recenti in cui si ha la sensazione di poter dire moltissimo (dati numerici e spaziali) ma a volte sfugge quella sintesi indispensabile per una interpretazione concreta, finalizzata alla costruzione di possibili esperienze fisiche. Per l’esplorazione dell’uso di dive…
Corte edu e Corte costituzionale tra operazioni di bilanciamento e precedente vincolante. Spunti teorico-generali e ricadute penalistiche (pt.II)
2019
Questo articolo è suddiviso in tre parti e si occupa delle interazioni complesse che si instaurano tra bilanciamenti di competenza della Corte edu e bilanciamenti di competenza della Corte costituzionale sul terreno dei conflitti tra diritti convenzionali e interessi costituzionalmente rilevanti tutelati dal sistema penale nazionale. La prima parte dell’articolo si concentra su un primo possibile modello di bilanciamento riscontrabile nella prassi applicativa del giudice sovranazionale, e cioè il bilanciamento ad hoc (o “caso per caso”); e arriva alla conclusione per cui, in questa prima famiglia di strategie decisionali, la Corte europea, rompendo la c.d. “connessione necessaria diritti/in…
Corte edu e Corte costituzionale tra operazioni di bilanciamento e precedente vincolante. Spunti teorico-generali e ricadute penalistiche (pt. I)
2019
This article is divided into three parts. The subject is the complex connections between the test balancing of the Italian Constitutional Court and that of the CEDU Court. Balancing between interests protected by European Convention and interests protected by national constitutional system. The “ad hoc balancing” is the first type of test balancing, according to the author, applied by CEDU Court to many judicial cases, which argues that the value protected by the European Convention is superior to the value protected by the national State. In the second part of the article, the author shows some judicial cases as examples of his argumentation. In the third part, the author analyzes the case…
Brevi note comparatistiche in tema di suicidio assistito
2019
The essay focuses on the legitimacy of assisted suicide in Italy and in England and Wales, particularly with regard to patients suffering from severe pain from incurable or terminal illnesses. In two recent cases (Cappato and Nicklinson), both Italian and English judges suggested to the Parliament to modify the current state of the law, without making a declaration of incompatibility with Article 8 of the Convention. The paper compares the approach of Corte Costituzionale and UK Supreme Court to the issue, revealing the ambiguity hidden behind those common decisions.
The structure of charoite, (K,Sr,Ba,Mn)(15-16)(Ca,Na)(32)[(Si-70(O,OH)(180))](OH,F)(4.0)center dot nH(2)O, solved by conventional and automated elect…
2010
AbstractCharoite, ideally (K,Sr,Ba,Mn)15–16(Ca,Na)32[(Si70(O,OH)180)](OH,F)4.0·nH2O, a rare mineral from the Murun massif in Yakutiya, Russia, was studied using high-resolution transmission electron microscopy, selected-area electron diffraction, X-ray spectroscopy, precession electron diffraction and the newly developed technique of automated electron-diffraction tomography. The structure of charoite (a= 31.96(6) Å,b= 19.64(4) Å,c= 7.09(1) Å, β = 90.0(1)°,V= 4450(24) Å3, space groupP21/m) was solvedab initioby direct methods from 2878 unique observed reflections and refined toR1/wR2= 0.17/0.21. The structure can be visualized as being composed of three different dreier silicate chains: a d…
Atomic structure solution of the complex quasicrystal approximant Al77Rh15Ru8 from electron diffraction data
2014
The crystal structure of the novel Al77Rh15Ru8phase (which is an approximant of decagonal quasicrystals) was determined using modern direct methods (MDM) applied to automated electron diffraction tomography (ADT) data. The Al77Rh15Ru8E-phase is orthorhombic [Pbma,a= 23.40 (5),b= 16.20 (4) andc= 20.00 (5) Å] and has one of the most complicated intermetallic structures solved solely by electron diffraction methods. Its structural model consists of 78 unique atomic positions in the unit cell (19 Rh/Ru and 59 Al). Precession electron diffraction (PED) patterns and high-resolution electron microscopy (HRTEM) images were used for the validation of the proposed atomic model. The structure of the E…