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A detailed mechanism of degradation behaviour of biodegradable as-ECAPed Zn-0.8Mg-0.2Sr with emphasis on localized corrosion attack

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Bioactive Materials 2023年第9期27卷 447-460页

作者： jan Pinc Andrea Skolakova Vojtech Hybasek Sarka Msallamova Petr Vertat Petr Ashcheulov martin Vondracek jan Duchon Ingrid McCarroll Matej Hývl Swarnendu Banerjee jan Drahokoupil Jirí Kubasek Dalibor Vojtech Jaroslav Capek Institute of Physics of the Czech Academy of Sciences Na Slovance 1999/2Prague 818221Czech Republic University of Chemistry and Technology Faculty of Chemical TechnologyDepartment of Metals and Corrosion EngineeringTechnicka 516628Praha 6-DejviceCzech Republic Max-Planck-Institut Für Eisenforschung Max-Planck-Straße 140237DüsseldorfGermany

In this study, advanced techniques such as atom probe tomography, atomic force microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy were used to determine the corrosion mechanism of the as-ECAPed Zn-0.8Mg-0.2Sr alloy. The influence of microstructural and surface features on the corrosion mechanism was investigated. Despite its significance, the surface composition before exposure is often neglected by the scientific community. The analyses revealed the formation of thin ZnO, MgO, and MgCO3 layers on the surface of the material before exposure. These layers participated in the formation of corrosion products, leading to the predominant occurrence of hydrozincite. In addition, the layers possessed different resistance to the environment, resulting in localized corrosion attacks. The segregation of Mg on the Zn grain boundaries with lower potential compared with the Zn-matrix was revealed by atom probe tomography and atomic force microscopy. The degradation process was initiated by the activity of micro-galvanic cells, specifically Zn - Mg2Zn11/SrZn13. This process led to the activity of the crevice corrosion mechanism and subsequent attack to a depth of 250 μm. The corrosion rate of the alloy determined by the weight loss method was 0.36 mm⋅a􀀀 1. Based on this detailed study, the degradation mechanism of the Zn-0.8Mg-0.2Sr alloy is proposed.

关键词： Biodegradable metals Zinc-based alloy Characterization Mechanism ECAP

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Comparative LIDT measurements of optical components for high-energy HiLASE lasers

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High Power Laser Science and Engineering 2016年第1期4卷 75-83页

作者： jan Vanda jan evcík Egidijus Pupka Mindaugas ciuka Andrius Melninkaitis martin Divoky Venkatesan Jambunathan Stefano Bonora Václav koda Antonio Lucianetti Danijela Rostohar Tomas Mocek Valdas Sirutkaitis Hilase Institute of Physics AS CR LIDARIS Ltd. Laser Research Center Vilnius University LUXOR Laboratory CNR IFN Crytur Ltd.

Further advancement of high-energy pulsed lasers requires a parallel development of appropriate optical *** different optical components, such as mirrors and antireflection-coated windows, which are essential for the design of Hi LASE high average power lasers were tested. The following paper summarizes results on the measurements of laser-induced damage threshold of such components, and clearly shows their capabilities and limitations for such a demanding application.

关键词： diode-pumped solid-state laser and applications laser-induced damage

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An Artificial Heart System for Testing and Evaluation of Cardiac Pacemakers

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Computers, Materials & Continua 2022年第12期73卷 6269-6287页

作者： martin Augustynek jan Kubicek Jaroslav Thomas Marek Penhaker Dominik Vilimek Michal Strycek Ondrej Sojka Antonino Proto Department of Cybernetics and Biomedical Engineering Faculty of Electrical Engineering and Computer ScienceVSB-Technical University of Ostrava17.Listopadu 15Ostrava–Poruba70800Czech Republic

The usability assessment of a pacemaker is a complex task where the dedicated programmer for testing programmed algorithms is *** paper provides the outcomes of development and complex testing of the artificial cardiac system to evaluate the pacemaker’s *** this work,we used the modular laboratory platform ELVIS II and created graphical user interface in LabVIEW programming *** electrical model of the heart allows signals generation(right atrium,right ventricle)and the monitoring of the stimulation *** LabVIEW user interface allows to set the parameters of the generated signals and the simulation of the cardiac rhythm disorders as well as the monitoring and visualization of the pacemaker behavior in *** results demonstrate the capability of proposed system to evaluate the paced and sensed *** proposed solution allows the scientists to test the behavior of any cardiac pacemaker for its pre-programmed settings and pacing *** addition,the proposed system can simulate various disorders and test cardiac pacemakers in different working modes.

关键词： Artificial heart cardiac conduction system electrical cardiac stimulation pacemaker

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On the central symmetry of the circumstellar envelope of RS Cnc

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Research in Astronomy and Astrophysics 2015年第5期15卷 713-724页

作者： Pham Tuyet Nhung Do Thi Hoai jan martin Winters Pierre Darriulat Eric Grard Thibaut Le Bertre VATLY INST 179 Hoang Quoc Viet Cau Giay Hanoi Vietnam LERMA UMR 8112 CNRS & Observatoire de Paris 61 av. de l’Observatoire F-75014 ParisFrance IRAM 300 rue de la Piscine Domaine Universitaire F-38406 St. Martin d’Heres France GEPI UMR 8111 CNRS & Observatoire de Paris 5 Place J. Janssen F-92195 Meudon CedexFrance

We present a phenomenological study of CO（1-0） and CO（2-1） emission from the circumstellar envelope （CSE） of the Asymptotic Giant Branch （AGB） star RS Cnc. It reveals departures from central symmetry that turn out to be efficient tools for the exploration of some of the properties of the CSE. We use a wind model including a bipolar flow with a typical wind velocity of ～8 km s^-1 that decreases to ～2 km s^-1 near the equator. This wind model is used to describe Doppler velocity spectral maps obtained by merging data collected at the IRAM Plateau de Bure Interferometer and Pico Veleta single dish radio telescope. Parameters describing the wind morphology and kinematics are obtained, together with the radial dependence of the gas temperature in the domain of the CSE probed by the CO observations. Significant north-south central asymmetries are revealed by the analysis, which we quantify using a simple phenomenological description. The origin of such asymmetries is unclear.

关键词： stars AGB and post-AGB -- stars individual (RS Cnc) -- stars mass loss -- radio lines general

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Design of a kJ-class HiLASE laser as a driver for inertial fusion energy

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High Power Laser Science and Engineering 2014年第2期2卷 1-10页

作者： Antonio Lucianetti Magdalena Sawicka Ondrej Slezak martin Divoky jan Pilar Venkatesan Jambunathan Stefano Bonora Roman Antipenkov Tomas Mocek HiLASE Project Institute of Physics AS CR Na Slovance 2 18221 Prague Czech Republic CNR-IFN Via Trasea 7 35131 Padova Italy ELI Beamlines Project Institute of Physics AS CR Na Slovance 2 18221 Prague Czech Republic

We present the results of performance modeling of a diode-pumped solid-state HiLASE laser designed for use in inertial fusion energy power plants. The main amplifier concept is based on a He-gas-cooled multi-slab architecture similar to that employed in Mercury laser system. Our modeling quantifies the reduction of thermally induced phase aberrations and average depolarization in Yb3+:YAG slabs by a combination of helium cryogenic cooling and properly designed(doping/width) cladding materials.

关键词： ASE birefringence cryogenic cooling slab lasers thermooptic effects

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The search for roAp stars: null results and new candidates from Strmgren-Crawford photometry

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Research in Astronomy and Astrophysics 2018年第11期18卷 43-54页

作者： Ernst Paunzen Gerald Handler Katerina Honkova Jakub Jurysek martin Masek Marek Drozdz jan janik Waldemar Ogtoza Lars Hermansson Mats Johansson martin Jelinek Marek Skarka Miloslav Zejda Department of Theoretical Physics and Astrophysics Masaryk UniversityKotlarska 2CZ-61137Czech Republic Nicolaus Copernicus Astronomical Center Bartycka 1800-716WarsawPoland Variable Star and Exoplanet Section of Czech Astronomical Society Vsetinska 941/78CZ-75701Valasske MeziriciCzech Republic Institute of Physics The Czech Academy of SciencesNa Slovance 1999/2CZ-18221PrahaCzech Republic Mt.Suhora Observatory Pedagogical UniversityPodchorazych 230-084KrakowPoland Sandvretens Observatory Linnegatan 5A75332UppsalaSweden Astronomical Institute Czech Academy of Sciences(ASU CAS)OndrejovCzech Republic

The rapidly oscillating Ap(roAp) stars exhibit pulsational photometric and/or radial velocity variations on time scales of several minutes, which are essential to test current pulsation models as well as our assumptions of atmospheric structure characteristics. In addition, their chemical peculiarity makes them very interesting for probing stellar formation and evolution in the presence of a global magnetic field. To date, a limited number of only 61 roAp stars is known to show photometric variability. On the other hand, a literature survey yields 619 unique stars that have unsuccessfully been searched for variability of this kind. Str o¨mgren-Crawford uvbyβ photometry of stars from both subgroups was used to investigate whether there is a selection bias for the investigated stars. We also present new photometric measurements(202 hours on 59 different nights) of 55 roAp candidates. We did not detect any new roAp star. Although our detection limits are comparable to other surveys, we also did not find pulsations in the known roAp star HD 12098, which may be a consequence of temporal amplitude changes. On the other hand, we do find some evidence for photometric variability of beta CrB at its spectroscopically derived pulsation period. From the uvbyβ photometry we conclude that the blue border of the roAp instability strip appears observationally well defined, whereas the red border is rather poorly known and *** these boundaries, a total of 4646 candidates were identified which appear worth investigating for short-term pulsational variability.

关键词： stars: chemically peculiar stars: early-type stars: variables: general techniques: photometric

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Noninvasive indocyanine green plasma disappearance rate predicts early complications,graft failure or death after liver transplantation

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Hepatobiliary & Pancreatic Diseases International 2011年第4期10卷 362-368页

作者： Lutz Schneider martin Spiegel Sebastian Latanowicz Markus A Weigand jan Schmidt Jens Werner Wolfgang Stremmel Christoph Eisenbach Department of General Surgery University of HeidelbergIm Neuenheimer Feld 110Heidelberg 69110Germany Department of Gastroenterology University of HeidelbergIm Neuenheimer Feld 410Heidelberg 69120Germany Department of Anaesthesiology University of HeidelbergIm Neuenheimer Feld 110Heidelberg 69110Germany

BACKGROUND:Early detection of graft malfunction or postoperative complications is essential to save patients and organs after orthotopic liver transplantation (OLT).Predictive tests for graft dysfunction are needed to enable earlier implementation of organ-saving interventions following *** study was undertaken to assess the value of indocyanine green plasma disappearance rates (ICG-PDRs) for predicting postoperative complications,graft dysfunction and patient survival following ***:Eighty-six patients undergoing OLT were included in this single-centre ***-PDR was assessed daily for the first 7 days following *** were graft loss or death within 30 days and postoperative complications,graft loss,or death within 30 ***:Postoperative complications of 31 patients included deaths (12 patients) or graft ***-PDR was significantly different in patients whose endpoints were graft loss or death beginning from day 3 and in those whose endpoints were graft loss,death,or postoperative complications beginning from day 4 after *** day 7 measurements,receiver operating characteristic curve analysis revealed an ICG-PDR cut-off for predicting death or graft loss of 9.6% per min (a sensitivity of 75.0%,a specificity of 72.6%,positive predictive value 0.35 negative predictive value 0.94).For prediction of graft loss,death or postoperative complications,the ICG-PDR cut-off was 12.3%per min (a sensitivity of 68.9%,a specificity of 66.7%,positive predictive value 0.57,negative predictive value 0.77).CONCLUSIONS:ICG-PDR measurements on postoperative day 7 are predictive of early patient outcomes following *** added value over that of routinely determined laboratory parameters is low.

关键词： indocyanine green liver function liver transplantation

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Preconditioning for a Phase-Field Model with Application to Morphology Evolution in Organic Semiconductors

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Communications in Computational Physics 2023年第6期33卷 1-17页

作者： Kai Bergermann Carsten Deibel Roland Herzog Roderick C.I.MacKenzie jan-Frederik Pietschmann martin Stoll Technische Universitat Chemnitz Faculty of Mathematics09107 ChemnitzGermany Technische Universitat Chemnitz Department of Physics09126 ChemnitzGermany Interdisciplinary Center for Scientific Computing Heidelberg University69120 HeidelbergGermany Durham University Department of EngineeringDurhamUK

The Cahn–Hilliard equations are a versatile model for describing the evolution of complex *** this paper we present a computational pipeline for the numerical solution of a ternary phase-field model for describing the nanomorphology of donor–acceptor semiconductor blends used in organic photovoltaic *** model consists of two coupled fourth-order partial differential equations that are discretized using a finite element *** order to solve the resulting large-scale linear systems efficiently,we propose a preconditioning strategy that is based on efficient approximations of the Schur-complement of a saddle point *** show that this approach performs robustly with respect to variations in the discretization ***,we outline that the computed morphologies can be used for the computation of charge generation,recombination,and transport in organic solar cells.

关键词： Preconditioning phase-field models organic solar cells Cahn-Hilliard finite element analysis

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Beam shaping in the high-energy kW-class laser system Bivoj at the HiLASE facility

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High Power Laser Science and Engineering 2023年第6期11卷 130-138页

作者： Tomáš Paliesek Petr Navrátil jan Pilar martin Divoký martin Smrž Tomáš Mocek HiLASE Centre Institute of Physics of the Czech Academy of SciencesDolni BrezanyCzech Republic Faculty of Nuclear Sciences and Physical Engineering Czech Technical University in PraguePragueCzech Republic

A fully automatic fail-safe beam shaping system based on a liquid crystal on a silicon spatial light modulator has been implemented in the high-energy kilowatt-average-power nanosecond laser system *** shaping system corrects for gain nonuniformity and wavefront aberrations of the front-end of the *** beam intensity profile and the wavefront at the output of the front-end were successfully improved by *** beam homogeneity defined by the beam quality parameters was improved two to three *** root-mean-square value of the wavefront was improved more than 10 ***,the shaped beam from the second preamplifier led to improvement of the beam profile at the output of the first main *** shaping system is also capable of creating nonordinary beam shapes,imprinting cross-references into the beam,or masking certain parts of the beam.

关键词： beam shaping high-average-power laser high-energy laser liquid crystal on silicon spatial light modulator wavefront shaping

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Foveal regeneration after resolution of cystoid macular edema without and with internal limiting membrane detachment:presumed role of glial cells for foveal structure stabilization

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International Journal of Ophthalmology(English edition) 2021年第6期14卷 818-833页

作者： Andreas Bringmann martin Karol jan Darius Unterlauft Thomas Barth Renate Wiedemann Leon Kohen Matus Rehak Peter Wiedemann Department of Ophthalmology and Eye Hospital University of LeipzigLeipzig 04103Germany Helios Klinikum Aue Aue 08280Germany

AIM: To document with spectral-domain optical coherence tomography the morphological regeneration of the fovea after resolution of cystoid macular edema(CME) without and with internal limiting membrane(ILM) detachment and to discuss the presumed role of the glial scaffold for foveal structure stabilization. METHODS: A retrospective case series of 38 eyes of 35 patients is described. Of these, 17 eyes of 16 patients displayed foveal regeneration after resolution of CME, and 6 eyes of 6 patients displayed CME with ILM detachment. Eleven eyes of 9 patients displayed other kinds of foveal and retinal disorders associated with ILM detachment. RESULTS: The pattern of edematous cyst distribution, with or without a large cyst in the foveola and preferred location of cysts in the inner nuclear layer or Henle fiber layer(HFL), may vary between different eyes with CME or in one eye during different CME episodes. Large cysts in the foveola may be associated with a tractional elevation of the inner foveal layers and the formation of a foveoschisis in the HFL. Edematous cysts are usually not formed in the ganglion cell layer. Eyes with CME and ILM detachment display a schisis between the detached ILM and nerve fiber layer(NFL) which is traversed by Müller cell trunks. ILM detachment was also found in single eyes with myopic traction maculopathy, macular pucker, full-thickness macular holes, outer lamellar holes, and glaucomatous parapapillary retinoschisis, and in 3 eyes with Müller cell sheen dystrophy(MCSD). As observed in eyes with MCSD, cellophane maculopathy, and macular pucker, respectively, fundus light reflections can be caused by different highly reflective membranes or layers: the thickened and tightened ILM which may or may not be detached from the NFL, the NFL, or idiopathic epiretinal membranes. In eyes with short single or multiple CME episodes, the central fovea regenerated either completely, which included the disappearance of irregularities of the photoreceptor l

关键词： fovea cystoid macular edema internal limiting membrane detachment Müller cell sheen dystrophy Müller glia astrocytes

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