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High Power Laser science and Engineering 2016年第2期4卷 14-28页

作者： Mario Ferianis Enrico Allaria Eugenio Ferrari Giulio Gaio Giuseppe Penco Fabio Rossi Marco Veronese Elettra-sincrotrone trieste s.C.p.A.

FERMI, the seeded free electron laser(FEL) in operation in Italy, is providing the User Community with unique fully coherent radiation, in the wavelength range 100–4 nm. FERMI is the first FEL fully synchronized by means of optical fibers. The optical timing system ensures an ultra-stable phase reference to its distributed clients. several femtosecond longitudinal diagnostics verify the achieved performance; the bunch length monitor(BLM) and the bunch arrival monitor(BAM) will be presented in this paper. Feedback systems play a crucial role to guarantee the needed longterm electron beam stability. A real-time infrastructure allows shot-to-shot communication between front-end computers and the servers. Orbit feedbacks are useful in machine tuning, whereas longitudinal feedbacks control electron energy,compression and arrival time. A flexible software framework allows a rapid implementation of heterogeneous multiinput–multi-output(MIMO) longitudinal loops simply by selecting the appropriate sensors and actuators.

关键词： feedback system femtosecond longitudinal diagnostics optical timing

Weak mismatch epitaxy and structural feedback in graphene growth on copper foil

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Nano Research 2013年第2期6卷 99-112页

作者： Neil R. Wilson Alexander J. Marsden Mohammed saghir Catherine J. Bromley Renald schaub Giovanni Costantini Thomas W. White Cerianne Partridge Alexei Barinov Pavel Dudin Ana M. sanchez James J. Mudd Marc Walker Gavin R. Bell Department of Physics University of Warwick Coventry CV4 7AL UK EastCHEM school of Chemistry University of St Andrews St Andrews KY16 9ST UK Department of Chemistry University of Warwick Coventry CV4 7AL UK sincrotrone trieste s.cp.a. Area Science Park 1-34012 Basovizza Trieste Italy

Graphene growth by low-pressure chemical vapor deposition on low cost copper foils shows great promise for large scale applications. It is known that the local crystallography of the foil influences the graphene growth rate. Here we find an epitaxial relationship between graphene and copper foil. Interfacial restructuring between graphene and copper drives the formation of （nl0） facets on what is otherwise a mostly Cu（100） surface, and the facets in turn influence the graphene orientations from the onset of growth. Angle resolved photoemission shows that the electronic structure of the graphene is decoupled from the copper indicating a weak interaction between them. Despite this, two preferred orientations of graphene are found, ±8° from the Cu[010] direction, creating a non-uniform distribution of graphene grain boundary misorientation angles. Comparison with the model system of graphene growth on single crystal Cu（110） indicates that this orientational alignment is due to mismatch epitaxy. Despite the differences in symmetry the orientation of the graphene is defined by that of the copper. We expect these observations to not only have importance for controlling and understanding the growth process for graphene on copper, but also to have wider implications for the growth of two-dimensional materials on low cost metal substrates.

关键词： graphene chemical vapordeposition mismatch epitaxy structural feedback low energy electrondiffraction angle resolvedphoto-emissionspectroscopy (ARPEs)

Transient measurement of phononic states with covariance-based stochastic spectroscopy

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Light(science & Applications) 2022年第3期11卷 68-75页

作者： Giorgia sparapassi stefano MCavaletto Jonathan Tollerud Angela Montanaro Filippo Glerean Alexandre Marciniak Fancesca Giusti shaul Mukamel Daniele Fausti Physics Department University of TriesteTriesteItaly Elettra-sincrotrone trieste s.C.p.A. TriesteItaly Department of Chemistry and Department of Physics&Astronomy University of CaliforniaIrvineCAUSA Optical sciences Centre Swinburne UniversityMelbourneAustralia

We present a novel approach to transient Raman spectroscopy,which combines stochastic probe pulses and a covariance-based detection to measure stimulated Raman signals in alpha-quartz.A coherent broadband pump is used to simultaneously impulsively excite a range of different phonon modes,and the phase,amplitude,and energy of each mode are independently recovered as a function of the pump-probe delay by a noisy-probe and covariance-based *** experimental results and the associated theoretical description demonstrate the feasibility of 2D-Raman experiments based on the stochastic-probe schemes,with new capabilities not available in equivalent mean-value-based 2D-Raman *** work unlocks the gate for nonlinear spectroscopies to capitalize on the information hidden within the noise and overlooked by a mean-value analysis.

关键词： stochastic spectroscopy coherent

Bone regeneration with adipose derived stem cells in a rabbit model

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The Journal of Biomedical Research 2019年第1期33卷 38-45页

作者： Michele Maglione Enrico salvador Maria E.Ruaro Mauro Melato Giuliana Tromba Daniele Angerame Lorenzo Bevilacqua Department of Medical sciences University of Trieste sIssA-International school for Advanced studies Department of Pathology and Legal Medicine University of Trieste Elettra-sincrotrone trieste s.C.p.A.

It has been shown that stem cells are able to calcify both in vitro and in vivo once implanted under the skin, if conveniently differentiated. Nowadays, however, a study on their efficiency in osseous regeneration does not exist in scientific literature and this very task is the real aim of the present experimentation. Five different defects of 6 mm in diameter and 2 mm in depth were created in the calvaria of 8 white New Zealand rabbits. Four defects were regenerated using 2 different conveniently modified scaffolds(Bio-Oss Block and Bio-Oss Collagen, Geistlich),with and without the aid of stem cells. After the insertion, the part was covered with a collagen membrane fixed by 5 modified titan pins(Altapin). The defect in the front was left empty on purpose as an internal control to each *** animals were sacrificed respectively after 2, 4, 6, 10 weeks. The samples were evaluated with micro-CT and histological analysis. Micro-CT analysis revealed that the quantity of new bone for samples with Bio-Oss Block and stem cells was higher than for samples with Bio-Oss Block alone. Histological analysis showed that regeneration occurred in an optimal way in every sample treated with scaffolds. The findings indicated that the use of adult stem cells combined with scaffolds accelerated some steps in normal osseous regeneration.

关键词： bone regeneration regenerative medicine stem cells tissue engineering

Contactless Monitoring of the Diameter-Dependent Conductivity of GaAs Nanowires

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Nano Research 2010年第10期3卷 706-713页

作者： Fauzia Jabeen silvia Rubini Faustino Martelli Alfonso Franciosi Andrei Kolmakov Luca Gregoratti Matteo Amati Alexei Barinov Andrea Goldoni Maya Kiskinova sincrotrone trieste s.C.P.A. Elettra LaboratoryArea Science ParkS.S.14Km.163.5I-34149 TriesteItaly Laboratorio TAsC IOM-CNR Area Science ParkS.S.14Km.163.5I-34149 TriesteItaly Department of Physics Southern Illinois University Carbondale1245 Lincoln Dr.Neckers 478CarbondaleIL 62901-4401USA

Contactless monitoring with photoelectron microspectroscopy of the surface potential along individual nano-structures,created by the X-ray nanoprobe,opens exciting possibilities to examine quantitatively size-and surface-chemistry-effects on the electrical transport of semiconductor nanowires(NWs).Implementing this novel approach-which combines surface chemical microanalysis with conductivity measurements-we explored the dependence of the electrical properties of undoped GaAs NWs on the NW width,temperature and surface *** following the evolution of the Ga 3d and As 3d core level spectra,we measured the position-dependent surface potential along the GaAs NWs as a function of NW diameter,decreasing from 120 to~20 nm,and correlated the observed decrease of the conductivity with the monotonic reduction in the NW diameter from 120 to~20 *** of the GaAs NWs to oxygen ambient leads to a decrease in their conductivity by up to a factor of 10,attributed to the significant decrease in the carrier density associated with the formation of an oxide shell.

关键词： semiconductor nanowires charge transport surface oxidation photoelectron X-ray microscopy charging GaAs

Fluorination of suspended graphene

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Nano Research 2017年第9期10卷 3151-3163页

作者： Claudia struzzi Mattia scardamaglia Nicolas Reckinger Jean-Francois Colomer Hikmet sezen Matteo Amati Luca Gregoratti Rony snyders Carla Bittencourt Chimie des Interactions Plasma-surface CIRMAP University of Mons 7000 Mons Belgium Research Group on Carbon Nanostructures (CARBONNAGe) University of Namur 5000 Namur Belgium Elettra - sincrotrone trieste s.C.p.A. di interesse nazionale Strada Statale 14 km 163.5 34149 Trieste Italy Materia Nova Research Center B-7000 Mons Belgium

suspended graphene is exposed to different fluorine-containing species produced by a plasma source fed with CF4 precursor gas. We investigate the fluorination process by selecting two different kinetic energies for the ions striking the graphene surface. The chemical-bonding environment is discussed, and the control of the graphene-fluorination homogeneity is investigated at the individual graphene sheets. The modifications of the electronic and structural properties are examined by scanning photoelectron microscopy, micro-Raman analysis, and scanning electron microscopy. The results are compared with those obtained for supported graphene on copper. suspended graphene provides a quasi-ideal model for investigating the intrinsic properties of irradiated carbon nano-systems while avoiding damage due to backscattered atoms and recoil due to a supporting substrate.

关键词： graphene fluorination spectromicroscopy X-ray photoelectron spectroscopy (XPs) Raman scanning electron microscopy (sEM)

There is life after coking for Ir nanocatalyst superlattices

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Nano Research 2022年第8期15卷 6969-6976页

作者： Antonio J.Martínez-Galera Haojie Guo Mariano D.Jiménez-sánchez stefano Franchi Kevin C.Prince José M.Gómez-Rodríguez Departamento de Física de la Materia Condensada Universidad Autónoma de MadridMadrid E-28049Spain Instituto Nicolás Cabrera Universidad Autónoma de MadridMadrid E-28049Spain Elettra-sincrotrone trieste s.C.p.A. in Area Science ParkBasovizza(Trieste)34149Italy Condensed Matter Physics Center(IFIMAC) Universidad Autónoma de MadridMadrid E-28049Spain

Achieving superior performance of nanoparticle systems is one of the biggest challenges in *** major phenomena,occurring during the reactions,hinder the development of the full potential of nanoparticle catalysts:sintering and contamination with carbon containing species,sometimes called ***,we demonstrate that Ir nanocrystals,arranged into periodic networks on hexagonal boron nitride(h-BN)supports,can be restored without sintering after contamination by persistent *** restoration yields the complete removal of carbon from the nanocrystals,which keep their crystalline structure,allowing operation without *** findings,together with the possibility of fine tuning the nanocrystals size,confer this nanoparticle system a great potential as a testbed to extract key information about catalysis-mediated oxidation *** the case of the CO oxidation by O2,reaction of interest in environmental science and green energy production,the existence of chemical processes not observed before in other nanoparticle systems is demonstrated.

关键词： catalysis coke nanoparticles scanning tunneling microscopy(sTM) X-ray photoemission spectroscopy(XPs)

size contrast of Pt nanoparticles formed on neighboring domains within suspended and supported graphene

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Nano Research 2018年第3期11卷 1589-1598页

作者： Dario Roccella Matteo Amati Hikmet sezen Rosaria Brescia Luca Gregoratti Universita degli studi di Genova - Facolta di scienze Matematiche Fisiche e Naturali Viale Benedetto XV Genova 3-16132 Italy Elettra - sincrotrone trieste s.C.p.A. in Area science Park SS 14-Km 163.5 Trieste 34149 Italy Electron Microscopy Facility Istituto Italiano di Tecnologia (liT) via Morego 30 Genova 16163 Italy

The relatively small size of thin （one or few layers） graphene flakes makes it extremely difficult to study the behavior of suspended graphene by characterization techniques other than the electron microscopies. Herein, we exploited the capability of spatially resolved photoemission in combination with high resolution transmission electron microscopy to investigate the interaction of thermally evaporated Pt atoms on suspended and supported graphene. spectroscopic and microscopic analyses reveal that the nucleation of nanometer- sized Pt particles in these two regions exhibit different trends. While only small nanometer-sized islands are present on the supported graphene, relatively larger clusters of islands were also found on the suspended flakes. The X-ray photoemission C ls core levels acquired after the Pt deposition show an increase in the number of vacancies in the graphene sheets.

关键词： graphene X-ray photoemissionspectroscopy scanning photoelectron microscop nanoparticles platinum suspended films

Anisotropic thermal expansion in high-entropy multicomponent AlB_(2)-type diboride solid solutions

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International Journal of Extreme Manufacturing 2023年第1期5卷 331-343页

作者： Frédéric Monteverde Mattia Gaboardi Federico saraga Lun Feng William Fahrenholtz Gregory Hilmas National Research Council of Italy Institute of Science Technology and Sustainability for CeramicsFaenza 48018RAItaly Elettra—sincrotrone trieste s.C.P.A Strada Statale 14—Km 1635 in AREA Science ParkBasovizza 34149TriesteItaly Missouri University of science and Technology RollaMO 65409United States of America AUREL spa I-47015(ModiglianaItaly) BLUE ORIGIN 98302(KentWashington US).

High-entropy(HE)ultra-high temperature ceramics have the chance to pave the way for future applications propelling technology advantages in the fields of energy conversion and extreme environmental *** others,HE diborides stand out owing to their intrinsic anisotropic layered structure and ability to withstand ultra-high ***,we employed in-situ high-resolution synchrotron diffraction over a plethora of multicomponent compositions,with four to seven transition metals,with the intent of understanding the thermal lattice expansion following different composition or synthesis *** a result,we were able to control the average thermal expansion(TE)from 1.3×10^(−6)to 6.9×10^(−6)K^(−1)depending on the combination of metals,with a variation of in-plane to out-of-plane TE ratio ranging from 1.5 to 2.8.

关键词： ultra-high temperature ceramics borides high-entropy ceramics spark plasma sintering synchrotron diffraction anisotropic thermal expansion

Modeling of ultrafast X-ray induced magnetization dynamics in magnetic multilayer systems

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npj Computational Materials 2022年第1期8卷 2044-2052页

作者： K.J.Kapcia V.Tkachenko F.Capotondi A.Lichtenstein s.Molodtsov L.Müller A.Philippi-Kobs P.Piekarz B.Ziaja Center for Free-Electron Laser science CFEL Deutsches Elektronen-Synchrotron DESYNotkestr.8522607HamburgGermany Institute of spintronics and Quantum Information Faculty of PhysicsAdam Mickiewicz University in PoznańPoznańPoland Institute of Nuclear Physics Polish Academy of SciencesKrakówPoland European XFEL GmbH SchenefeldGermany Elettra-sincrotrone trieste s.C.p.A TriesteBasovizzaItaly University of Hamburg HamburgGermany Deutsches Elektronen-synchrotron DEsY Notkestr.8522607HamburgGermany

In this work,we report on modeling results obtained with our recently developed simulation tool enabling nanoscopic description of electronic processes in X-ray irradiated ferromagnetic *** this tool,we have studied the response of Co/Pt multilayer system irradiated by an ultrafast extreme ultraviolet pulse at the M-edge of Co(photon energy~60 eV).It was previously investigated experimentally at the FERMI free-electron-laser facility,using the magnetic small-angle X-ray scattering *** simulations show that the magnetic scattering signal from cobalt decreases on femtosecond timescales due to electronic excitation,relaxation,and transport processes both in the cobalt and in the platinum layers,following the trend observed in the experimental *** confirmation of the predominant role of electronic processes for X-ray induced demagnetization in the regime below the structural damage threshold is a step toward quantitative control and manipulation of X-ray induced magnetic processes on femtosecond timescales.

关键词： magnetization multilayer cobalt