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4. Visible-light photoactivity of Bi-pyrochlores with high Fe contentsMatjaž Valant, Metka Benčina, Mattia Fanetti, 2014, izvirni znanstveni članek Najdeno v: osebi
Ključne besede: fotoaktivnost, fotokataliza, katalizatorji, kemijska kinetika, materiali, piroklorna struktura, rekombinacija, železove spojine
Objavljeno: 30.12.2015; Ogledov: 29182; Prenosov: 573
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6. THE MORPHOLOGY DEPENDENCE ON GROWTH PARAMETERS IN NANOSTRUCTURED SEMICONDUCTORSMiha Gunde, 2014, diplomsko delo Opis: Poly(3-hexylthiophene) (P3HT) is an organic semiconductor material that is widely studied in the photovoltaics and transistor fields of research. The polymer exhibits a relatively high charge carrier mobility when the molecules are ordered in a crystalline way. In this
case the material exhibits a fibril-like morphology, which is usually studied by atomic force microscopy (AFM). Previous studies show that blending P3HT with graphene can further improve the charge carrier transport properties of the film. In this experiment, the scanning electron microscope (SEM) has been chosen, due to its practical aspects such as speed of operation and ease of use. Three sets of samples have been analyzed, containing films made of P3HT+graphene blends at different concentrations. The aims of the experiment are:
i) to find good conditions for the observation of the morphology features of the film
ii) to perform a morphological analysis of the surface of three sets of samples containing both pure P3HT, and P3HT+graphene blend, and possibly to highlight correlation between morpholgy and the charge transport properties.
Surface analysis is done by detecting the secondary electron (SE) emission, which is sensitive to topographical features of the surface. Good observation conditions were established by coating the specimen with a thin layer of conductive coating, using a high energy beam (30 keV), and tilting the sample to an angle (30 ◦ ). In two out of three of the analyzed pure P3HT films, the presence of fibrilles indicated a possibly good charge mobility, which has
been confirmed by electrical measurements using time-of-flight photoconductivity method (TOF). The presence of graphene has only slightly modified morphology of the film. Features of graphene flakes, which lie flat in the film, have been observed such as flake edges and folds. The flakes are homogeneously dispersed in the film without forming any connected network. TOF measurements have shown an increase in mobility of the charge carriers in the P3HT+graphene film.
Najdeno v: osebi
Ključne besede: scanning electron microscope, organic semiconductor thin film, P3HT, graphene, morphology
Objavljeno: 01.12.2016; Ogledov: 5488; Prenosov: 155
 Polno besedilo (30,93 MB) |
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8. Gamma and x-ray irradiation effects on different Ge and Ge/F doped optical fibersAziz Boukenter, N. Richard, Marco Cannas, Claude Marcandella, Layla Martin-Samos, Simonpietro Agnello, Diego Di Francesca, Mattia Fanetti, Imene Reghioua, Sylvain Girard, Antonino Alessi, Youcef Ouerdane, 2015, izvirni znanstveni članek Najdeno v: osebi
Ključne besede: optical fibers, Germanium, doping, cathodoluminescence, irradiation effect
Objavljeno: 11.04.2016; Ogledov: 4740; Prenosov: 0
Polno besedilo (1,35 MB) |
9. Characterization of Nd2Fe14B sintered magnets and effect of addition TbF and DyF by Grain Boundary Diffusion ProcessJan Ferjančič, 2016, magistrsko delo Opis: Sintrani Nd2Fe14B magneti tretje generacije so večinoma uporabljeni v avtomobilski in transportni industriji. Sintranim magnetom s strukturo Nd2Fe14B so dodane težke redke zemlje (TRZ, e.g. Dy in Tb). Ta vrsta magnetov je uporabljena v električnih pomožnih sistemih (EPS), ki vrtijo volanski drog. Zahtevani lastnosti magnetov v EPS motorjih (v MAHLE Letriki d.o.o.) sta remanenca (Br) 1240-1350 mT in koercitivnost (Hcj) ≥1592 kA/m. Dodajanje TRZ omogoča, da magnet ohranja svojo magnetnost tudi pri visokih temperaturah, kar pa občutno poveča ceno magneta. V zadnjih letih so proizvajalci magnetov razvili novo metodo, tako imenovan postopek interkristalne difuzije Tb in Dy. Difuzija prične med termično obdelavo končanega magneta prevlečenim s slojem TRZ. Med termično obdelavo TRZ difundirajo s površine v notranjost magneta prek kristalne strukture Nd in med zrna Fe, rezultat je visoka prostorska razpršenost TRZ. Interkristalna difuzija omogoča, da lahko ima magnet z manjšo vsebnostjo TRZ enako ali boljšo koercitivnost in remanenco v primerjavi s standardnim postopkom.
Cilj naloge je karakterizacija magnetov, z osredotočenostjo na opis mikrostrukturne homogenosti, homogenosti kristalnih območij in homogenost posameznih elementov v magnetni strukturi. S ciljem, da se definira posebnost interkristalnega difuzijskega postopka. Analiza magnetov v prerezu je bila izvedena z vrstičnim elektronskim mikroskopom (SEM) v povezavi z energijsko disperzijsko rentgensko spektroskopijo (EDX), s katero smo določali lokalne elemente.
Z opazovanjem mikrostrukture smo želeli potrditi homogenost celotne magnetne strukture, kljub nekaterim nehomogenostim pridobljenih iz drugih člankov. Opazili smo razlike v homogenosti med različnimi magneti le pri standardnem postopku. Kljub vsemu povprečna vrednost komponent in prostorska razporeditev elementov potrjuje naše predpostavke.
Najdeno v: osebi
Ključne besede: NdFeB magneti, interkristalna difuzija TRZ, SEM in EDX
Objavljeno: 29.07.2016; Ogledov: 6610; Prenosov: 292
Polno besedilo (4,17 MB) |
10. ORR stability of Mn–Co/polypyrrole nanocomposite electrocatalysts studied by quasi in-situ identical-location photoelectron microspectroscopyMaya Kiskinova, Claudio Mele, Hikmet Sezen, Benedetto Bozzini, Mattia Fanetti, Andrea Goldoni, Luca Gregoratti, Belen Aleman, Matteo Amati, Patrizia Bocchetta, 2016, izvirni znanstveni članek Opis: The stability of pyrolyzed Mn–Co/polypyrrole (PPy) nanocomposites towards the Oxygen Reduction Reaction (ORR)
in alkaline solution, was studied with a close-knit group of complementary microscopic and space-resolved spectroscopic
approaches: Atomic Force Microscopy (AFM), Scanning and High-Resolution Transmission Electron
Microscopy (SEM, HRTEM) and identical-location Scanning PhotoElectron Microscopy (SPEM). Tracking quasi-in
situ the morphochemical evolution of the Mn–Co/PPy catalyst upon electrochemical aging under ORR conditions
by this multi-technique approach, has allowed to clarify the key physico-chemical processes underlying
the dramatic impact of Co additions to stability improvement.
Najdeno v: osebi
Ključne besede: Mixed manganese oxides, Polypyrrole, Oxygen reduction, Electrocatalysis, Nanocomposites, X-ray photoelectron microspectroscopy
Objavljeno: 25.07.2016; Ogledov: 4321; Prenosov: 0
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