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Exploring fs-laser irradiation damage subthreshold behavior of dielectric mirrors via electrical measurements

High Power Laser Science and Engineering 2024年第2期12卷 24-32页

作者： Petrisor Gabriel Bleotu Radu Udrea Alice Dumitru Olivier Uteza Maria-Diana Mihai Dan Gh Matei Daniel Ursescu stefan Irimiciuc Valentin Craciun Extreme Light Infrastructure-Nuclear Physics(ELI-NP) Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering(IFIN-HH)MagureleRomania Doctoral School of Physics University of BucharestMagureleRomania LULI-CNRS CEAUniversite SorbonneEcole PolytechniqueInstitut Polytechnique de ParisPalaiseau CEDEXFrance Apel Laser IlfovRomania Aix-Marseille University CNRSLP3 UMR 7341MarseilleFrance Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering(IFIN-HH) MagureleRomania University Politehnica of Bucharest BucharestRomania National Institute for Lasers Plasma and Radiation Physics MagureleRomania

With ultrafast laser systems reaching presently 10 PW peak power or operating at high repetition rates,research towards ensuring the long-term,trouble-free performance of all laser-exposed optical components is *** work is focused on providing insight into the optical material behavior at fluences below the standardized laser-induced damage threshold(LIDT)value by implementing a simultaneous dual analysis of surface emitted particles using a Langmuir probe(LP)and the target current(TC).HfO_(2) and ZrO_(2) thin films deposited on fused silica substrates by pulsed laser deposition at various O_(2) pressures for defect and stoichiometry control were irradiated by Gaussian,ultrashort laser pulses(800 nm,10 Hz,70 fs)in a wide range of *** TC and LP collected signals were in good agreement with the existing theoretical description of laser–matter interaction at an ultrashort time *** approach for an in situ LIDT monitoring system provides measurable signals for below-threshold irradiation conditions that indicate the endurance limit of the optical surfaces in the single-shot energy scanning *** LIDT value extracted from the LP-TC system is in line with the multipulse statistical analysis done with ISO 21254-2:2011(E).The implementation of the LP and TC as on-shot diagnostic tools for optical components will have a significant impact on the reliability of next-generation ultrafast and high-power laser systems.

关键词： HfO_(2) in situ detection Langmuir probe laser-induced damage threshold target current ZrO_(2)

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Influence of symmetric and asymmetric rolling on texture evolution of work-hardened AA 5xxx aluminium alloy

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Transactions of Nonferrous Metals Society of China 2024年

作者： Matja? Godec stefan Zaefferer Jakob Kraner ?rtomir Donik Irena Paulin Institute of Metals and Technology Max-Planck-Institut für Eisenforschung Max-Planck-Strasse 1 Impol 2000 d.d. Partizanska cesta 38

The textures and microstructures of hot- and cold-rolled sheets of an AA 5454 aluminium alloy were studied， with special attention paid to comparing the texture development for the symmetric and asymmetric cold rolling. Scanning electron microscopy with electron-backscatter diffraction was used to monitor the development of the microstructure in the differently deformed and additionally annealed samples. Details of the formations and transformations of individual texture components occurring during the rolling processes were observed and discussed. The average grain sizes， textures and mechanical properties were correlated and explained for the symmetric and asymmetric cold-rolled samples. The asymmetric rolling is beneficial in terms of deep drawability because it reduces the planar anisotropy of the annealed material due to the decrease of the Cube， Goss， Rotated Cube and η- fibre texture components and the same time strengthens X1- and X2-fibre texture components which are shear texture components and improve deep drawability. During the asymmetric cold rolling， the temperature increases due to friction， triggering recrystallisation processes and leading to larger grains. It was also confirmed that asymmetric cold rolling uses less rolling force and consequently less energy to produce a final material with better formability， particularly earing.

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Tailoring the microstructure， tensile properties， and creep resistance of additively manufactured Inconel 718 superalloy by post-processing

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Transactions of Nonferrous Metals Society of China 2024年

作者： Sajad Ghaemifar Milad Roostaei Mohammad Reza Zamani stefan Wurster Hamed Mirzadeh School of Metallurgy and Materials Engineering College of Engineering University of Tehran Erich Schmid Institute of Materials Science Austrian Academy of Sciences Department of Materials Science Chair of Materials Physics Montanuniversit?t Leoben

Effects of post-processing heat treatments on the microstructure， aging kinetics， and room/elevated temperature mechanical properties of additively manufactured Inconel 718 superalloy were investigated. Scanning electron microscopy (SEM)， electron backscattered diffraction (EBSD)， and X-ray diffraction (XRD)， as well as hardness， tensile， and creep testing were used for characterization. At temperatures higher than 1100 °C， homogenization treatment resulted in the appearance of equiaxed grains by recrystallization and diminishing the dislocation density. The precipitation activation energy for the homogenized aged condition was obtained as 203 kJ/mol， which was higher than the value of ～160 kJ/mol for the as-built IN718 superalloy. Therefore， direct aging resulted in a faster aging response， which led to a significant improvement in tensile properties， as rationalized by the strengthening mechanisms. Direct aging treatment resulted in a higher elevated-temperature ultimate tensile strength (UTS) as well as the optimum creep life and lowest minimum creep rate in comparison with other heat treating routes， which were attributed to the presence of fine and uniformly dispersed strengthening precipitates in conjunction with the high dislocation density.

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Optical probing of ultrafast laser-induced solid-to-overdense-plasma transitions

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Light(Science & Applications) 2024年第5期13卷 973-984页

作者： Yasmina Azamoum Georg Alexander Becker Sebastian Keppler Guillaume Duchateau stefan Skupin Mickael Grech Fabrice Catoire Sebastian Hell Issa Tamer Marco Hornung Marco Hellwing Alexander Kessler Franck Schorcht Malte Christoph Kaluza GSI Helmholtzzentrum für Schwerionenforschung Planckstr.164291 DarmstadtGermany. Helmholtz Institute Jena Fröbelstieg 307743 JenaGermany. Institute of Optics and Quantum Electronics Friedrich-SchillerUniversität JenaMax-Wien-Platz 107743 JenaGermany. CEA-CESTA 15 Avenue des SablièresCS6000133116 Le BarpCedexFrance Institut Lumière Matière UMR 5306-CNRSUniversitéde Lyon 169622 VilleurbanneFrance. LULI CNRSCEASorbonne UniversitéInstitut Polytechnique de ParisPalaiseauFrance. Universitéde Bordeaux-CNRS-CEA CELIAUMR 5107 TalenceFrance

Understanding the solid target dynamics resulting from the interaction with an ultrashort laser pulse is a challenging fundamental multi-physics problem involving atomic and solid-state physics,plasma physics,and laser *** of the initial interplay of the underlying processes is essential to many applications ranging from lowpower laser regimes like laser-induced ablation to high-power laser regimes like laser-driven ion *** the properties of the so-called pre-plasma formed as the laser pulse’s rising edge ionizes the target is complicated from the theoretical and experimental point of view,and many aspects of this laser-induced transition from solid to overdense plasma over picosecond timescales are still open *** the one hand,laser-driven ion acceleration requires precise control of the pre-plasma because the efficiency of the acceleration process crucially depends on the target properties at the arrival of the relativistic intensity peak of the *** the other hand,efficient laser ablation requires,for example,preventing the so-called“plasma shielding”.By capturing the dynamics of the initial stage of the interaction,we report on a detailed visualization of the pre-plasma formation and ***-thin diamond-like carbon foils are shown to transition from solid to plasma during the laser rising edge with intensities<10^(16)W/cm^(2).Single-shot near-infrared probe transmission measurements evidence sub-picosecond dynamics of an expanding plasma with densities above 10^(23)cm^(−3)(about 100 times the critical plasma density).The complementarity of a solid-state interaction model and kinetic plasma description provides deep insight into the interplay of initial ionization,collisions,and expansion.

关键词： laser acceleration solid

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Fetal lung growth predicts the risk for early-life respiratory infections and childhood asthma

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World Journal of Pediatrics 2024年第5期20卷 481-495页

作者： Dimitra E.Zazara Olympia Giannou Steven Schepanski Mirja Pagenkemper Anastasios D.Giannou Maike Pincus Ioannis Belios stefan Bonn Ania C.Muntau Kurt Hecher Anke Diemert Petra Clara Arck Division for Experimental Feto-Maternal Medicine Department of Obstetrics and Fetal MedicineUniversity Medical Center Hamburg-Eppendorf(UKE)Martinistraße 5220251HamburgGermany University Children’s Hospital UKEHamburgGermany Computer Engineering and Informatics Department Polytechnic SchoolUniversity of PatrasPatrasGreece Institute of Developmental Neurophysiology Center for Molecular Neurobiology Hamburg(ZMNH)UKEHamburgGermany Department of Obstetrics and Fetal Medicine UKEHamburgGermany Department of General Visceral and Thoracic SurgeryUKEHamburgGermany Section of Molecular Immunology and Gastroenterology Ⅰ.Department of MedicineUKEHamburgGermany Pediatrics and Pediatric Pneumology Practice BerlinGermany Institute of Medical Systems Biology ZMNHUKEHamburgGermany Hamburg Center for Translational Immunology UKEHamburgGermany

Background Early-life respiratory infections and asthma are major health burdens during *** predicting an increased risk for early-life respiratory diseases are ***,we identified the predictive value of ultrasound-monitored fetal lung growth for the risk of early-life respiratory infections and *** Fetal lung size was serially assessed at standardized time points by transabdominal ultrasound in pregnant women participating in a pregnancy *** between fetal lung growth and respiratory infections in infancy or early-onset asthma at five years were ***-learning models relying on extreme gradient boosting regressor or classifier algorithms were developed to predict respiratory infection or asthma risk based on fetal lung *** model development and validation,study participants were randomly divided into a training and a testing group,respectively,by the employed *** Enhanced fetal lung growth throughout pregnancy predicted a lower early-life respiratory infection *** sex was associated with a higher risk for respiratory infections in *** lung growth could also predict the risk of asthma at five years of *** designed three machine-learning models to predict the risk and number of infections in infancy as well as the risk of early-onset *** models’R2 values were 0.92,0.90 and 0.93,respectively,underscoring a high accuracy and agreement between the actual and predicted *** variables included known risk factors and novel predictors,such as ultrasound-monitored fetal lung *** Sonographic monitoring of fetal lung growth allows to predict the risk for early-life respiratory infections and asthma.

关键词： Asthma Child risk Early-life respiratory infections Prenatal lung development Sexual dimorphism

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The dual role of microglia in ischemic stroke and its modulation via extracellular vesicles and stem cells

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Neuroprotection 2024年第1期2卷 4-15页

作者： Matteo Haupt stefan T.Gerner Thorsten R.Doeppner Department of Neurology University of Gottingen Medical SchoolGottingenGermany Department of Neurology University Hospital GiessenGiessenGermany Center for Mind Brain and Behavior(CMBB)University of Marburg and Justus Liebig University GiessenMarburgGermany Department of Anatomy and Cell Biology Medical University of VarnaVarnaBulgaria Medipol University Istanbul Research InstituteforHealthSciencesand Technologies(SABITA)IstanbulTurkey

Stem cell-based therapies and extracellular vesicle(EV)treatment have demonstrated significant potential for neuroprotection against ischemic *** the neuroprotective mechanisms are not yet fully under-stood,targeting microglia is central to promoting *** are the resident immune cells of the central nervous *** cells are crucial in the pathogenesis of ischemic *** respond rapidly to the site of injury by releasing pro-inflammatory cytokines,phagocytizing dead cells and debris,and recruiting peripheral immune cells to the ischemic *** these responses are essential for clearing damage and initiating tissue repair,excessive or prolonged microglial activation can exacerbate brain injury,leading to secondary neuroinflammation and ***,microglia exhibit a dynamic range of activation states with the so-called M1 pro-inflammatory and M2 anti-inflammatory phenotypes,representing the two ends of the *** delivery of both EVs and stem cells modulates microglial activation,suppressing pro-inflammatory genes,influencing the expression of transcription factors,and altering receptor expression,ultimately contributing to *** findings underscore the importance of understanding the complex and dynamic role of microglia in the development of effective neuroprotective strategies to reduce the effects of ischemic *** this review,we examine the current state of knowledge regarding the role of microglia in ischemic stroke,including their molecular and cellular mechanisms,activation states,and interactions with other *** also discuss the multifaceted contributions of microglia to stem cell-and EV-based neuroprotection during an ischemic stroke to provide a comprehensive understanding of microglial functions and their potential implications in stroke therapies.

关键词： extracellular vesicle microglia neuroprotection stroke stem cells

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Towards greener polymers:Trends in the German chemical industry

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Green Carbon 2024年第1期2卷 33-44页

作者： Adam W.Franz stefan Buchholz Rolf W.Albach Rolf Schmid BASF SE Ludwigshafen 67056Germany Evonik Operations GmbH Hanau 63457Germany Association for Chemistry and Economics German Chemical SocietyFrankfurt am Main 60444Germany Stuttgart University and Bio4Business Stuttgart 70569Germany

Global plastics production is expected to exceed 400 million tons and reach 600 million tons by *** synthesis currently accounts for approximately 3%of global greenhouse gas *** 60%of all polymers are produced for *** include shopping bags,packaging materials,mulch films,and soluble polymers for cosmetics and other ***,only a portion of single-use plastic is recycled or disposed of in incinerators or *** estimated 20%is not disposed of properly and pollutes the global environment,especially the *** response to these challenges,the United Nations,European Union,and many nation-states are developing regulatory frameworks that encourage the chemical industry to produce plastics with a smaller environmental footprint and often support this through research *** solutions include:(1)the use of green energy,green hydrogen,bio-based feedstocks,or CO_(2) in synthesis;(2)the reuse or recycling of plastics through conversion or pyrolysis;and(3)the production of biodegradable *** German chemical industry contributes approximately one-third of polymer production in the *** is embedded in the EU regulatory and research landscape and anchored in the European Green Deal,which aims for carbon neutrality by *** this paper,we describe how BASF and Evonik,two leading German chemical companies with strong but different polymer portfolios,respond to the call for greener polymers and how technologies are being developed to make polyurethanes,a particularly important and difficult-to-recycle family of elastomers and duromers,renewable and *** the environmental footprint of plastics requires not only innovative materials but also proper governance,regulatory and collection systems,and public willingness to *** an international comparison of these competencies,expressed by the"polymer management index"(PMI),Germany achieved a top position.

关键词： Plastics recycling Biobased plastics Biodegradable plastics Polymer management index European Green Deal

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Demonstrating grating-based phase-contrast imaging of laser-driven shock waves

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Matter and Radiation at Extremes 2024年第4期9卷 90-97页

作者： Leonard Wegert Stephan Schreiner Constantin Rauch Bruno Albertazzi Paulina Bleuel Eric Frojdh Michel Koenig Veronika Ludwig Artem SMartynenko Pascal Meyer Aldo Mozzanica Michael Müller Paul Neumayer Markus Schneider Angelos Triantafyllidis Bernhard Zielbauer Gisela Anton Thilo Michel stefan Funk Plasma Physics Department GSI Helmholtzzentrum fur SchwerionenforschungPlanckstraBe 164291 DarmstadtGermany Erlangen Centre for Astroparticle Physics(ECAP) Friedrich-Alexander-Universität Erlangen-NurnbergNikolaus-Fiebiger-StraBe 291058 ErlangenGermany LULI-CNRS CEASorbonne UniversitésEcole PolytechniqueInstitut Polytechnique de ParisF-91120 Palaiseau CedexFrance Paul Scherrer Institut(Psi) Forschungsstrasse 1115232VilligenSwitzerland Karlsruhe Institute of Technology Institute of Microstructure TechnologyHermann-von-Helmholtz-Platz 176344 Eggenstein-LeopoldshafenGermany

Single-shot X-ray phase-contrast imaging is used to take high-resolution images of laser-driven strong shock *** a two-grating Talbot interferometer,we successfully acquire standard absorption,differential phase-contrast,and dark-field images of the shocked *** agreement is demonstrated between experimental data and the results of two-dimensional radiation hydrodynamics simulations of the laser-plasma *** main sources of image noise are identified through a thorough assessment of the interferometer’s *** acquired images demonstrate that grating-based phase-contrast imaging is a powerful diagnostic tool for high-energy-density *** addition,we make a novel attempt at using the dark-field image as a signal modality of Talbot interferometry to identify the microstructure of a foam target.

关键词： interaction. shock phase

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Single-emitter super-resolved imaging of radiative decay rate enhancement in dielectric gap nanoantennas

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Light(Science & Applications) 2024年第1期13卷 47-54页

作者： R.Margoth Córdova-Castro Bart van Dam Alberto Lauri stefan A.Maier Riccardo Sapienza Yannick De Wilde Ignacio Izeddin Valentina Krachmalnicoff Institut Langevin ESPCI ParisPSL UniversityCNRSParisFrance The Blackett Laboratory Department of PhysicsImperial College LondonLondonUK School of Physics and Astronomy Monash UniversityClaytonVictoriaAustralia Chair in Hybrid Nanosystems Ludwig-Maximilians Universität MünchenMuenchenGermany Department of Physics University of OttawaOttawaONCanada

High refractive index dielectric nanoantennas strongly modify the decay rate via the Purcell effect through the design of radiative *** to their dielectric nature,the field is mainly confined inside the nanostructure and in the gap,which is hard to probe with scanning probe *** we use single-molecule fluorescence lifetime imaging microscopy(smFLIM)to map the decay rate enhancement in dielectric GaP nanoantenna dimers with a median localization precision of 14 *** measure,in the gap of the nanoantenna,decay rates that are almost 30 times larger than on a glass *** comparing experimental results with numerical simulations we show that this large enhancement is essentially radiative,contrary to the case of plasmonic nanoantennas,and therefore has great potential for applications such as quantum optics and biosensing.

关键词： dielectric decay radiative

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如何消除老员工的技术焦虑

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商业评论 2024年第5期 143-149页

作者：斯特凡·塔姆斯李君蒙特利尔高等商学院

很少有企业的人力战略会包容各种年龄层,考虑"多代同堂"的因素.似乎更少有企业能认识到,办公技术在推动不同年龄层员工的绩效方面可发挥重要作用.但是,根据经济合作与发展组织的数据,随着劳动力人口结构的日渐老龄化,越来越多的人职场...

很少有企业的人力战略会包容各种年龄层,考虑"多代同堂"的因素.似乎更少有企业能认识到,办公技术在推动不同年龄层员工的绩效方面可发挥重要作用.但是,根据经济合作与发展组织的数据,随着劳动力人口结构的日渐老龄化,越来越多的人职场生命的延长,企业的成功和生产力与60岁以上年长员工的幸福感和工作绩效之间的关系将越来越紧密.

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