1,343 research outputs found

    Propagation of Coherent Light Pulses with PHASE

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    The current status of the software package PHASE for the propagation of coherent light pulses along a synchrotron radiation beamline is presented. PHASE is based on an asymptotic expansion of the Fresnel Kirchhoff integral stationary phase approximation which is usually truncated at the 2nd order. The limits of this approximation as well as possible extensions to higher orders are discussed. The accuracy is benchmarked against a direct integration of the Fresnel Kirchhoff integral. Long range slope errors of optical elements can be included by means of 8th order polynomials in the optical element coordinates w and l. Only recently, a method for the description of short range slope errors has been implemented. The accuracy of this method is evaluated and examples for realistic slope errors are given. PHASE can be run either from a built in graphical user interface or from any script language. The latter method provides substantial flexibility. Optical elements including apertures can be combined. Complete wave packages can be propagated, as well. Fourier propagators are included in the package, thus, the user may choose between a variety of propagators. Several means to speed up the computation time were tested among them are the parallelization in a multi core environment and the parallelization on a cluste

    On the formation of the welding seams with high speed

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    Целью настоящей работы является определение направлений исследований по установлению возможности повышения качества формирования сварочных швов с повышенной скоростью формирования тела шва. В статье вопрос решается путём отклонения сварочной дуги углом вперед, поперечным магнитным полем. Дополнительное магнитное поле в зоне сварки генерируют, пропуская часть сварочного тока по присадочной проволоке. Проволока подается в сварочную ванну позади дуги параллельно электроду в плоскости свариваемого стыка, в направлении, противоположном току дуги. Проведенный анализ отечественных и зарубежных литературных источников по рассматриваемой теме показал, что современный подход к определению влияния на повышение качества формирования сварочных швов с повышенной скоростью формирования тела шва, за счет дополнительного поперечного магнитного поля является актуальным в настоящее время и недостаточно изучен. Приведены сведения о формировании тела шва при скоростной сварке вольфрамовым электродом с присадочной проволокой, которые могут быть использованы для повышения производительности сварочных работ.The aim of this work is to determine the areas of research to establish the possibility of improving the quality of the formation of welds with an increased rate of formation of the joint body. In the article the problem is solved by the deviation of the arc angle forward transverse magnetic field. Additional magnetic field generated in the welding zone by passing part of the welding current for the filler wire. The wire is fed into the weld puddle behind the arc electrode in the plane parallel to the welded joint, in a direction opposite to the arc current. The analysis of domestic and foreign literature on the topic has shown that the modern approach to determine the effect on the improvement of quality of formation of welds with an increased rate of formation of the joint body, due to the additional transverse magnetic field is relevant in the present and not fully understood. Information is given about the formation of a seam in the tungsten electrode welding with filler wire, which can be used to improve the performance of welding

    A Robust and Universal Metaproteomics Workflow for Research Studies and Routine Diagnostics Within 24 h Using Phenol Extraction, FASP Digest, and the MetaProteomeAnalyzer

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    The investigation of microbial proteins by mass spectrometry (metaproteomics) is a key technology for simultaneously assessing the taxonomic composition and the functionality of microbial communities in medical, environmental, and biotechnological applications. We present an improved metaproteomics workflow using an updated sample preparation and a new version of the MetaProteomeAnalyzer software for data analysis. High resolution by multidimensional separation (GeLC, MudPIT) was sacrificed to aim at fast analysis of a broad range of different samples in less than 24 h. The improved workflow generated at least two times as many protein identifications than our previous workflow, and a drastic increase of taxonomic and functional annotations. Improvements of all aspects of the workflow, particularly the speed, are first steps toward potential routine clinical diagnostics (i.e., fecal samples) and analysis of technical and environmental samples. The MetaProteomeAnalyzer is provided to the scientific community as a central remote server solution at www.mpa.ovgu.de.Peer Reviewe

    Quantum Zeno effect in the Cooper-pair transport through a double-island Josephson system

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    Motivated by recent experiments, we analyze transport of Cooper pairs through a double-island Josephson qubit. At low bias in a certain range of gate voltages coherent superpositions of charge states play a crucial role. Analysis of the evolution of the density matrix allows us to cover a wide range of parameters, incl. situations with degenerate levels, when dissipation strongly affects the coherent eigenstates. At high noise levels the so-called Zeno effect can be observed, which slows down the transport. Our analysis explains certain features of the I-V curves, in particular the visibility and shape of resonant peaks and lines

    A new compact soft x ray spectrometer for resonant inelastic x ray scattering studies at PETRA III

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    We present a newly designed compact grating spectrometer for the energy range from 210 eV to 1250 eV, which would include the K amp; 945;1,2 emission lines of vital elements like C, N, and O. The spectrometer is based on a grazing incidence spherical varied line spacing grating with 2400 l mm at its center and a radius of curvature of 58 542 mm. First, results show a resolving power of around 1000 at an energy of 550 eV and a working spectrometer for high vacuum 10 amp; 8722;4 mbar environment without losing photon intensit

    Spatial stochastic resonance in 1D Ising systems

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    The 1D Ising model is analytically studied in a spatially periodic and oscillatory external magnetic field using the transfer-matrix method. For low enough magnetic field intensities the correlation between the external magnetic field and the response in magnetization presents a maximum for a given temperature. The phenomenon can be interpreted as a resonance phenomenon induced by the stochastic heatbath. This novel "spatial stochastic resonance" has a different origin from the classical stochastic resonance phenomenon.Comment: REVTex, 5 pages, 3 figure

    Photodetection of propagating quantum microwaves in circuit QED

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    We develop the theory of a metamaterial composed of an array of discrete quantum absorbers inside a one-dimensional waveguide that implements a high-efficiency microwave photon detector. A basic design consists of a few metastable superconducting nanocircuits spread inside and coupled to a one-dimensional waveguide in a circuit QED setup. The arrival of a {\it propagating} quantum microwave field induces an irreversible change in the population of the internal levels of the absorbers, due to a selective absorption of photon excitations. This design is studied using a formal but simple quantum field theory, which allows us to evaluate the single-photon absorption efficiency for one and many absorber setups. As an example, we consider a particular design that combines a coplanar coaxial waveguide with superconducting phase qubits, a natural but not exclusive playground for experimental implementations. This work and a possible experimental realization may stimulate the possible arrival of "all-optical" quantum information processing with propagating quantum microwaves, where a microwave photodetector could play a key role.Comment: 27 pages, submitted to Physica Scripta for Nobel Symposium on "Qubits for Quantum Information", 200

    Personhood, consciousness, and god : how to be a proper pantheist

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    © Springer Nature B.V. 2018In this paper I develop a theory of personhood which leaves open the possibility of construing the universe as a person. If successful, it removes one bar to endorsing pantheism. I do this by examining a rising school of thought on personhood, on which persons, or selves, are understood as identical to episodes of consciousness. Through a critique of this experiential approach to personhood, I develop a theory of self as constituted of qualitative mental contents, but where these contents are also capable of unconscious existence. On this theory, though we can be conscious of our selves, consciousness turns out to be inessential to personhood. This move, I then argue, provides resources for responding to the pantheist’s problem of God’s person.Peer reviewedFinal Accepted Versio

    Optimized isolation of 7,7′-biphyscion starting from Cortinarius rubrophyllus, a chemically unexplored fungal species rich in photosensitizers

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    Mushrooms such as the dermocyboid Cortinarius rubrophyllus are characterized by strikingly colorful fruiting bodies. The molecular dyes responsible for such colors recently experienced a comeback as photoactive compounds with remarkable photophysical and photobiological properties. One of them-7,7'-biphyscion-is a dimeric anthraquinone that showed promising anticancer effects in the low nanomolar range under blue-light irradiation. Compared to acidic anthraquinones, 7,7'-biphyscion was more efficiently taken up by cells and induced apoptosis after photoactivation. However, seasonal collection of mushrooms producing this compound, low extraction yields, and tricky fungal identification hamper further developments to the clinics. To bypass these limitations, we demonstrate here an alternative approach utilizing a precursor of 7,7'-biphyscion, i.e., the pre-anthraquinone flavomannin-6,6'-dimethyl ether, which is abundant in many species of the subgenus Dermocybe. Controlled oxidation of the crude extract significantly increased the yield of 7,7'-biphyscion by 100%, which eased the isolation process. We also present the mycochemical and photobiological characterization of the yet chemically undescribed species, i.e. C. rubrophyllus. In total, eight pigments (1-8) were isolated, including two new glycosylated anthraquinones (1 and 2). Light-dependent generation of singlet oxygen was detected for the first time for emodin-1-O-beta-D-glucopyranoside (3) [photophysical measurement: Phi(Delta) =0.11 (CD3OD)]. Furthermore, emodin (7) was characterized as promising compound in the photocytotoxicity assay with EC50-values in the low micromolar range under irradiation against cells of the cancer cell lines AGS, A549, and T24.Metals in Catalysis, Biomimetics & Inorganic Material
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