274 research outputs found

    Stand-alone device for the electrolytic fabrication of scanning near-field optical microscopy aperture probes

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    Haumann C, Pelargus C, Frey HG, et al. Stand-alone device for the electrolytic fabrication of scanning near-field optical microscopy aperture probes. Review of scientific instruments. 2005;76(3): 033704.Near-field optical applications require the fast, stable, and reproducible fabrication of scanning near-field optical microscopy (SNOM) aperture probes in the submicrometer range. We have developed a stand-alone device for the electrolytic etching of nanoapertures with an integrated current and optical transmission monitoring and control. Probes with an aperture ranging from 50 to 100 nm were reproducibly fabricated with great reliability. With these probes, high resolution SNOM images of 100 nm test patterns and single dye molecules (Rhodamine 6G in poly(vinyl alcohol)) are measured and presented. Not requiring a SNOM setup, the stand-alone device is not only inexpensive and compact, but also insensitive to external disturbances

    Efficient Quantum Analytic Nuclear Gradients with Double Factorization

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    Efficient representations of the Hamiltonian such as double factorization drastically reduce circuit depth or number of repetitions in error corrected and noisy intermediate scale quantum (NISQ) algorithms for chemistry. We report a Lagrangian-based approach for evaluating relaxed one- and two-particle reduced density matrices from double factorized Hamiltonians, unlocking efficiency improvements in computing the nuclear gradient and related derivative properties. We demonstrate the accuracy and feasibility of our Lagrangian-based approach to recover all off-diagonal density matrix elements in classically-simulated examples with up to 327 quantum and 18470 total atoms in QM/MM simulations, with modest-sized quantum active spaces. We show this in the context of the variational quantum eigensolver (VQE) in case studies such as transition state optimization, ab initio molecular dynamics simulation and energy minimization of large molecular systems.Comment: 22 pages, 5 figure

    Functional architecture and specifications for Tolerancing Data and Knowledge Management

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    Part 1: Knowledge ManagementInternational audienceThe paper deals with the Computer-Aided Tolerancing and Product Data Management. It is especially focus on data and knowledge management system to support and improve the tolerancing tasks in product development process. The first part of the paper introduces an overview about the recent developments related to tolerancing supports and data management systems. Based on a literature survey and industrial issues, the second part proposes a functional architecture and specifications of the data and knowledge manage-ment system addressing the numerous needs clarified by tolerancing experts

    Synchroneity of major late Neogene sea level fluctuations and paleoceanographically controlled changes as recorded by two carbonate platforms

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    Shallow-water carbonate systems are reliable recorders of sea level fluctuations and changes in ambient seawater conditions. Drilling results from Ocean Drilling Program (ODP) Legs 133 and 166 indicate that the timing of late Neogene sedimentary breaks triggered by sea level lowerings is synchronous in the sedimentary successions of the Queensland Plateau and the Great Bahama Bank. This synchrony indicates that these sea level changes were eustatic in origin. The carbonate platforms were also affected by contemporary, paleoceanographically controlled fluctuations in carbonate production. Paleoceanographic changes are recorded at 10.7, 3.6, and 1.7–2.0 Ma. At the Queensland Plateau, sea surface temperature shifts are documented by shifts from tropical to temperate carbonates (10.7 Ma) and vice versa (3.6 Ma); the modern tropical platform was established at 2.0–1.8 Ma. At Great Bahama Bank, changes were registered in compositional variations of platform-derived sediment, such as major occurrence of peloids (3.6 Ma) and higher rates of neritic carbonate input (1.7 Ma). The synchroneity of these changes attests to the far-field effects of modifications in the oceanographic circulation on shallow-water, low-latitude carbonate production

    Safety and results of image-guided vertebroplasty with elastomeric polymer material (elastoplasty)

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    BACKGROUND: Image-guided elastoplasty is an innovative method for percutaneous vertebral augmentation with a silicone elastomeric material. Our aim was to evaluate its technical success, safety and efficacy as well as the rate of secondary fractures. METHODS: Nineteen patients (13 women and 6 men, age 72\u2009\ub1\u200910 years, mean\u2009\ub1\u2009standard deviation) underwent elastoplasty between 2010 and 2016. A total of 33 vertebrae were treated. A total of 2-6 mL of silicone-based elastomeric polymer material (VK100) was used. Visual analogue scale (VAS) and Oswestry disability index (ODI) pain scores were used. RESULTS: In all cases, it was possible to complete the procedure (technical success 100%). No major complications occurred. In 6/19 (31.5%) patients, asymptomatic leakage of the material was observed during the procedure. Full pain recovery was obtained in 18/19 (94%) patients. One patient with a painful angioma did not experience any change in symptoms. VAS and ODI were significantly reduced after the procedure, from 7.9\u2009\ub1\u20091.1 to 0.7\u2009\ub1\u20091.4 and from 79.6\u2009\ub1\u200912% to 9.9\u2009\ub1\u200914% respectively (p\u2009<\u20090.001 for both comparisons). After vertebroplasty, 14 of 15 patients (93%) removed the brace and 16/19 (84%) completely stopped using any drugs for pain relief (p\u2009<\u20090.001 for both pre-procedure versus post-procedure comparisons). At a mean follow-up time of 26.5\u2009\ub1\u200928.1 months (median 8.7 months, range 6-69 months), no secondary fracture occurred. CONCLUSION: Taking into consideration the relatively small sample size, image-guided elastoplasty seems to be a safe procedure providing effective pain control over time

    A seasonal cycle of terrestrial inputs in Lake Van, Turkey

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    Abstract Lake Van in Turkey is the world&apos;s largest soda lake (607 km 3 ). The lake&apos;s catchment area is estimated to be ∼12,500 km 2 , and the terrestrial input is carried through eolian, riverine, snowmelt and anthropogenic paths. Extent and seasonality of the terrestrial inputs to the lake have not been studied, but it is essential to evaluate its environmental status and to assess the use of environmental proxies to estimate the lake&apos;s response to climate changes. This study aims to measure seasonal changes in terrestrial input of natural and anthropogenic origin as recorded by the fluxes of pollen and biomarkers of soil bacteria and vascular or higher plants, as well as petrogenic biomarkers in monthly resolved sediment traps from August 2006 to July 2007. Fluxes of pollen, soil and higher plant biomarkers seem to be related to precipitation and snowmelt in autumn and spring. In addition, dust storms, which are common during the summer months, may have resulted in long-distance transport. Anthropogenic biomarker fluxes indicate yearround petrogenic contamination although some mature biomarker fluxes are higher in summer and in late winterspring. The relative changes between petrogenic markers indicate variations in the pollutant sources

    Quark--anti-quark potential in N=4 SYM

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    We construct a closed system of equations describing the quark--anti-quark potential at any coupling in planar N=4 supersymmetric Yang-Mills theory. It is based on the Quantum Spectral Curve method supplemented with a novel type of asymptotics. We present a high precision numerical solution reproducing the classical and one-loop string predictions very accurately. We also analytically compute the first 7 nontrivial orders of the weak coupling expansion. Moreover, we study analytically the generalized quark--anti-quark potential in the limit of large imaginary twist to all orders in perturbation theory. We demonstrate how the QSC reduces in this case to a one-dimensional Schrodinger equation. In the process we establish a link between the Q-functions and the solution of the Bethe-Salpeter equation.Comment: 31 pages, 1 figure; v2: minor correcton
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