Search results for: XRFS

• Local ordering of nano-structured Pt probed by multiple-scattering XAFS

  Publication

  • A. Witkowska
  • A. Di Cicco
  • E. Principi

  - PHYSICAL REVIEW B - Year 2007

  W pracy przedstawiono wyniki analizy MS EXAFS krystalicznej platyny i nanostruktur platyny (klastry o rozmiarach od 1nm do 7nm). Rezultaty analizy masowej platyny (uwzględniające rozkłady dwu i trój-ciałowe) są zgodne z wcześniejszymi danymi strukturalnymi i wibracyjnymi i stały się podstawą do realistycznej analizy EXAFS nanocząstek Pt realizownej w połączeniu z wynikami pomiarów TEM, SEM i XRD. Badaniom poddano nanocząstki Pt...

  Full text available to download

• XAFS investigations of nitrided NbN-SiO2 sol-gel derived films

  Publication

  • A. Witkowska
  • B. Kościelska

  - JOURNAL OF NON-CRYSTALLINE SOLIDS - Year 2012

  Praca poświęcona jest wykorzystaniu analizy widm XAFS zmierzonych na krawędzi K atomów Nb do badania struktury cienkich warstw NbN-(100-x)SiO2 (x = 100, 80, 60 mol%) otrzymanych techniką zol-żel poprzez wysokotemperaturowe wygrzewanie warstw Nb2O5-SiO2 w atmosferze NH3. Otrzymana struktura filmu jest złożona z granul NbN ulokowanych w matrycy SiO2. Analiza XAFS pokazuje, że we wszystkich próbkach w lokalnym otoczeniu niobu znajduje...

  Full text to download in external service

• PtCo cathode electrocatalyst behaviour viewed by in-situ XAFS fuel cell measurements

  Publication

  • A. Witkowska
  • S. Dsoke
  • E. Principi
  • R. Marassi
  • A. Di Cicco
  • V. Rossi Albertini

  - JOURNAL OF POWER SOURCES - Year 2008

  W pracy zostały przedstawione wstępne wyniki analizy XAS (X-ray absorption spectroscopy), TEM (transmission electron microscopy) i XRD (X-ray diffraction) nanostruktur PtCo 1:1 (20% fazy metalicznej osadzonej na węglu, Vulcan XC-72) używanych jako elektrokatalizatory w polimerowych ogniwach paliwowych (PEM FC). Pomiary realizowane były również w warunkach pracy ogniwa paliwowego za pomocą specjalnie zoptymalizowanej do pomiarów...

  Full text to download in external service

• Investigating the effects of structural pounding on the seismic performance of adjacent RC and steel MRFs

  Publication

  • F. Kazemi
  • M. Miari
  • R. Jankowski

  - Bulletin of Earthquake Engineering - Year 2021

  An insufficient separation distance between adjacent buildings is the main reason for structural pounding during severe earthquakes. The lateral load resistance system, fundamental natural period, mass, and stiffness are important factors having the influence on collisions between two adjacent structures. In this study, 3-, 5- and 9-story adjacent reinforced concrete and steel Moment Resisting Frames (MRFs) were considered to investigate...

  Full text available to download

• Temperature and potential-dependent structural changes in Pt cathode electrocatalyst viewed by in situ XAFS

  Publication

  • A. Witkowska
  • E. Principi
  • A. Di Cicco
  • S. Dsoke
  • R. Marassi
  • L. Olivi
  • M. Centazzo
  • V. Rossi Albertini

  - JOURNAL OF NON-CRYSTALLINE SOLIDS - Year 2008

  W pracy przedstawiono wyniki badań widm absorpcji promieniowania rentgenowskiego nano-platyny używanej jako katalizator w katodach polimerowych ogniw paliwowych (PEM FC). Badania XAFS realizowane były w warunkach pracy ogniwa paliwowego. Wysokiej jakości widma, uzyskane za pomocą specjalnie przygotowanej do pomiarów XAFS in situ komórki FC, umożliwiły przeprowadzenie zaawansowanej analizy obrazującej zmiany w lokalnej strukturze...

  Full text to download in external service

• Nano-structured Pt embedded in the acidic salts of heteropolymolybdate matrices: MS XAFS study

  Publication

  • A. Witkowska
  • S. Dsoke
  • R. Marassi
  • A. Di Cicco

  - Synchrotron Radiation in Natural Science - Year 2014

  Multiple-scattering extended X-ray absorption fine structure (MS EXAFS) study combined with TEM and XRD analysis of a novel Pt-based catalyst operating at low temperature fuel cells (FCs) is presented. Innovation in the case of the considered catalyst resides in the use of a porous inorganic matrix of acidic heteropolymolybdate salts as a catalyst support. Obtained results show the relation between the matrix composition and the...

  Full text to download in external service

• Fe local structure in Pt-free nitrogen-modified carbon based electrocatalysts: XAFS study

  Publication

  • A. Witkowska
  • G. Giuli
  • M. Renzi
  • F. Nobili
  • M. Longhi

  - Journal of Physics : Conference Series - Year 2016

  The paper presents a new results on the bonding environment (coordination number and geometry) and on oxidation states of Fe in nitrogen-modified Fe/C composites used as Pt-free catalysts for oxygen reduction in Direct Hydrogen Fuel Cells. Starting from glucose or fructose, two catalysts displaying different electrochemical performance were prepared and studied in the form of pristine powder and thin catalytic layer of electrode...

  Full text available to download

• Performance of Vector-valued Intensity Measures for Estimating Residual Drift of Steel MRFs with Viscous Dampers

  Publication

  • B. Mohebi
  • F. Kazemi
  • N. Asgarkhani
  • P. Ghasemnezhadsani
  • A. Mohebi

  - International Journal of Structural and Civil Engineering Research - Year 2022

  Viscous Dampers (VDs) are widely used as passive energy dissipation system for improving seismic performance levels especially in retrofitting of buildings. Residual Inter-story Drift Ratio (R-IDR) is another important factor that specifies the condition of building after earthquake. The values of R-IDR illustrates the possibility of retrofitting and repairing of a building. Therefore, this study aims to explore the vector-valued...

  Full text available to download

• XRF analysis of heavy metals contents in oak wood (Quercur robur L.)

  Publication

  • A. Balicka
  • D. Szadkowska

  - Annals of WULS, Forestry and Wood Technology - Year 2020

  Full text to download in external service

• Quasi Real-Time XRF Spectrometer in Source Apportionment of PM10 in a Typical Suburban Area

  Publication

  • T. Mach
  • J. Rybak
  • J. Bihałowicz
  • W. Rogula-Kozłowska

  - Journal of Ecological Engineering - Year 2022

  Full text to download in external service