Time Dynamics of the Down-Coupling Phenomenon in 3-D NAND Strings

We present a detailed analysis of the time dynamics of the down-coupling phenomenon (DCP) in 3-D NAND Flash memory strings. The transient time dynamics of the channel potential following the wordline (WL) bias transition fromthe pass voltage to zero is studied via numerical simulation, highlighting the existence of three temporal regimes controlledby different physical processes: electron emission from traps, hole injection from the string edges followed by capture, and propagation along the string. The impact of these processes is separately studied, followed by an analysis of the dependence of the DCP recovery time on architectural parameters. Results highlight the relevant physics and can be used as a design guideline for NAND strings with reduced sensitivity to the DCP

Inherited Ocean-Continent Transition zones in deeply subducted terranes: Insights from Alpine Corsica

In the Schistes Lustrés of Alpine Corsica (France) serpentinized mantle rocks are associated with continental basement and meta-volcanic/-sedimentary cover rocks. The relationships among these different lithologies are especially well exposed in the Monte San Petrone unit, where Alpine metamorphism reached lawsonite-eclogite conditions. The contact between serpentinites and slivers of continental basement, relatively flat-lying over several kilometers, is characterized by evidence of cataclastic deformation pre-dating Alpine High-Pressure ductile fabrics. The serpentinite/continental basement pair is stratigraphically overlain by metasediments with a typical Jurassic-Cretaceous supra-ophiolitic lithostratigraphy, with metaradiolarites passing upward to marbles and calcschists. Noticeably, no evidence of cataclastic deformation is found in metasediments. These observations indicate that the lithostratigraphy of the Monte San Petrone unit was established during a pre-Alpine polyphase evolution, which culminated in extensive brittle deformation along a flat-lying detachment fault prior to the deposition of Jurassic sediments. We suggest that the inferred Mesozoic extensional tectonics were related to the opening of the Western Tethys. The Mesozoic architecture of the Monte San Petrone area, which is typical of an Ocean-Continent Transition (OCT) zone, was preserved despite Alpine deformation and metamorphism, when the different lithologies (i.e. meta-ophiolites, continent-derived rocks and metasediments) underwent a common metamorphic evolution, culminating at T=490-550. °C and P=2.2-2.6. GPa. Similar tectono-stratigraphic associations are observed in other high-pressure terranes of Alpine Corsica, suggesting that inherited OCT-type domains may be common in Alpine-type orogens. © 2011 Elsevier B.V

Electrode-dependent asymmetric conduction mechanisms in K0.5Na0.5NbO3 micro-capacitors

The ultimate performance of devices employing lead-free piezoelectrics is determined not only by the intrinsic properties of the piezo, but also by processes and materials employed to create the electric contacts. In this paper, we investigate the impact of different metallic electrodes with increasing chemical reactivity (Pt, Ni, Ti, Cr), on the asymmetric behavior of the leakage current in M/K0.5Na0.5NbO3/Pt(111) micro-capacitors, where M stands for the top metallic electrode. For all electrodes we found a marked leakage asymmetry that we ascribed to the presence of a Schottky-like rectifying junction at the M/K0.5Na0.5NbO3/Pt(111) bottom interface, while the corresponding junction at the top interface is deeply affected by the creation of oxygen vacancies due to oxygen scavenging during the growth of the top metallic electrodes, leading to an almost ohmic top contact. The leakage increases with the reactivity of the electrodes, while the asymmetry decreases, thus suggesting that the creation of the top metal/K0.5Na0.5NbO3 interface generates oxygen vacancies diffusing down to the bottom interface and impacting on the rectifying behavior of the Schottky-like junction. Noteworthy, this asymmetric conduction can reflect in an asymmetric piezoelectric and ferroelectric behavior, as a sizable portion of the applied voltage drops across the rectifying junction in reverse bias, thus hampering symmetric bipolar operation, especially in leaky materials

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The hERG1 potassium channel behaves as prognostic factor in gastric dysplasia endoscopic samples

Purpose: Gastric cancer (GC) is still a relevant health issue worldwide. The identification of prognostic factors for progression of gastric dysplasia (GD), the main pre-cancerous lesion of the intestinal-type GC, is hence mandatory.Patients and methods: A cohort of 83 GD endoscopic samples belonging to Italian subjects was collected. hERG1 expression was evaluated by immunohistochemistry and scored 0-3, depending on the percentage of stained cells. Expression data were analysed in conjunction with clinico-pathological and survival data.Results: hERG1 turned out to be expressed in 67.47% (56 out of 83) of the GD samples. hERG1 expression was higher in high-grade GD compared to low-grade GD (29 out of 39, 74.36% vs 27 out of 44, 61.36%), although the statistical significance was not reached (P=0.246). No association emerged between hERG1 expression and clinical features of the patients (age, gender, localization, H. pylori infection, gastritis and intestinal metaplasia). In a subset of cases for which sequential samples of gastric lesions (from GD to Early Gastric Cancer and Advanced Gastric Cancer) were available, hERG1 expression was maintained in all the steps of gastric carcinogenesis from GD onwards. A general trend to increased expression in advanced lesions was observed. hERG1 score had a statistically significant impact on both Progression-Free Survival (P=0.018) and Overall Survival (P=0.031). In particular, patients displaying a high hERG1 score have a shorter survival.Conclusion: hERG1 is aberrantly expressed in human GD samples and has an impact on both PFS and OS, hence representing a novel prognostic marker for progression of GD towards GC of the intestinal histotype. Once properly validated, hERG1 detection could be included in the clinical practice, during endoscopic surveillance protocols, for the management of GD at higher risk of progression, as already proposed for Barrett's oesophagus

Provenance, protolith and metamorphic ages of jadeite-bearing orthogneiss and host paragneiss at Tavagnasco, the Sesia Zone, Lower Aosta Valley, Italy

An eclogite-facies orthogneiss and host paragneiss from a quarry near Tavagnasco in the Lower Aosta Valley were studied in order to refine the protolith, provenance and metamorphic ages of the Eclogitic Micaschist Complex of the Sesia Zone. The orthogneiss contains jadeite with quartz + phengite + K-feldspar ± garnet + rutile + zircon, whereas the paragneiss hosts garnet + jadeite + phengite ± glaucophane + epidote + rutile + quartz. Phase diagram modeling of two representative samples yields minimum equilibration conditions of 550 ± 50 ∘C and 18 ± 2 kbar. Cathodoluminescence images of zircon from the orthogneiss show oscillatory-zoned cores that are embayed and overgrown by complex, oscillatory-zoned rims. Four concordant secondary ion mass spectrometry analyses from the cores give a weighted mean 206Pb / 238U age of 457 ± 5 Ma. The cores have Th/U = 0.1 and negative Eu anomalies indicative of an igneous protolith, which we interpret to have crystallized in the Ordovician at 780 ∘C, based on Ti-in-zircon measurements. Zircon rims yield a range of 206Pb / 238U dates from 74 to 86 Ma, and four concordant analyses define a weighted mean 206Pb / 238U age of 78 ± 2 Ma. The rims are interpreted to have grown in the eclogite facies based on their lower Th/U (0.01), less negative Eu anomalies and steeper heavy rare earth element (HREE) patterns at &lt;600 ∘C. The paragneiss yielded a detrital zircon population with major peaks at 575–600, 655 and 765 Ma; minor older components; and a maximum depositional age of approximately 570 Ma. The prominent Neoproterozoic zircon population and Ediacaran depositional age suggest derivation from the Gondwana margin. The metamorphic zircon is consistent with the oldest eclogite-facies event in the Sesia Zone; it does not show evidence of multiple periods of rim growth or any pre-Alpine (e.g., Variscan) metamorphism.</p

On the geometry of C^3/D_27 and del Pezzo surfaces

We clarify some aspects of the geometry of a resolution of the orbifold X = C3/D_27, the noncompact complex manifold underlying the brane quiver standard model recently proposed by Verlinde and Wijnholt. We explicitly realize a map between X and the total space of the canonical bundle over a degree 1 quasi del Pezzo surface, thus defining a desingularization of X. Our analysis relys essentially on the relationship existing between the normalizer group of D_27 and the Hessian group and on the study of the behaviour of the Hesse pencil of plane cubic curves under the quotient.Comment: 23 pages, 5 figures, 2 tables. JHEP style. Added references. Corrected typos. Revised introduction, results unchanged

CO2 photoconversion to fuels under high pressure : effect of TiO2 phase and of unconventional reaction conditions

Artificial photosynthesis is an up to date topic for the fixation of CO2 in form of valuable fuels. Recently, we set up an innovative concept of photoreactor to be applied to CO2 photoreduction, enabling operation up to 20 bar. This allows to improve CO2 solubility and to explore unconventional operating conditions for this very challenging reaction. Following a preliminary communication, to demonstrate the validity of the approach systematic testing has been here carried out on different TiO2 photocatalysts (anatase, rutile and anatase + rutile) doped with 0.1 wt% Au, by tuning pressure, temperature and pH. The operating conditions have been selected to maximise the production of gas phase products, i.e. CH4 + H2, with respect to liquid phase organic compounds. The present results overperform many of the recent achievements reported in the literature and throw the basis for a further optimisation of the photocatalytic material and of the photoreactor