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  • 1.
    Bergsåker, Henric
    et al.
    KTH, Tidigare Institutioner (före 2005), Alfvénlaboratoriet.
    Ilyinsky, L.
    Portnoff, G.
    Ion beam analysis of sputter-deposited gold films for quartz resonators2000Ingår i: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 30, nr 1, s. 620-622Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sputter deposition using a focused ion beam has been investigated as an alternative to magnetron sputtering for the deposition of thin-film gold electrodes onto quartz resonators. One potential concern is the inclusion of argon in the growing film when argon ions are used for sputtering. Argon retention in sputter-deposited gold films using an 11.5 keV argon ion beam was investigated with Rutherford backscattering spectrometry and it was found that in layers deposited at close to normal ejection angles the argon trapping was at the level of less than or equal to 1 at,%, similar to magnetron-deposited layers, whereas argon incorporation increased with the ejection angle up to several per cent at large angles.

  • 2.
    Brismar, Hjalmar
    et al.
    KTH, Centra, Science for Life Laboratory, SciLifeLab. Karolinska Inst, Astrid Lindgren Childrens Hosp, Dept Woman & Child Hlth, Sweden.
    Aperia, A
    Westin, L
    Moy, J
    Wang, M
    Guillermier, C
    Poczatek, C
    Lechene, C
    Study of protein and RNA in dendritic spines using multi-isotope imaging mass spectrometry (MIMS).2014Ingår i: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 46, nr Suppl 1Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The classical view of neuronal protein synthesis is that proteins are made in the cell body and then transported to their functional sites in the dendrites and the dendritic spines. Indirect evidence, however, suggests that protein synthesis can directly occur in the distal dendrites, far from the cell body. We are developing protocols for dual labeling of RNA and proteins using (15)N-uridine and (18)O- or (13)C-leucine pulse chase in cultured neurons to identify and localize both protein synthesis and fate of newly synthesized proteins. Pilot experiments show discrete localization of both RNA and newly synthesized proteins in dendrites, close to dendritic spines. We have for the first time directly imaged and measured the production of proteins at the subcellular level in the neuronal dendrites, close to the functional sites, the dendritic spines. This will open a powerful way to study neural growth and synapse plasticity in health and disease.

  • 3. Coullerez, G.
    et al.
    Lundmark, S.
    Malmström, Eva
    KTH, Tidigare Institutioner                               , Fiber- och polymerteknologi.
    Hult, Anders
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Mathieu, H. J.
    ToF-SIMS for the characterization of hyperbranched aliphatic polyesters: probing their molecular weight on surfaces based on principal component analysis (PCA)2003Ingår i: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 35, nr 8, s. 693-708Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A series of 2,2-bis(hydroxymethyl)propionic acid (Bis-MPA) hyperbranched aliphatic polyesters with different molecular weights (generations) is analysed for the first time by time-of-flight secondary ion mass spectrometry (ToF-SIMS). The main negative and positive low-mass fragments are identified in the fingerprint part of the spectra (m/z < 400) and are principally assigned to fragmentation of the Bis-MPA repeating units. In addition, it is shown that the fragmentation pattern is highly affected by the functional end-groups. This is illustrated for a phthalic acid end-capped hyperbranched polymer and for an acetonide-terminated dendrimer analog. Also, typical fragments assigned to the ethoxylated pentaerythritol core molecule are detected. These ions show decreasing intensities with increasing molecular weight. This intensity dependency on the generation is used to calibrate the molecular weight of hyperbranched polyesters on the surface. To obtain quantitative information, a principal component analysis WCA) multivariate statistical method is applied to the ToF-SIMS data. The influence of different normalization procedures prior to PCA calculation is tested, e.g. normalization to the total intensity, to the intensities of ions assigned to the Bis-MPA repeating unit or to intensities of fragments due to the core molecule. It is shown that only one principal component (PC1) is needed to describe most of the variance between the samples. In addition, PC1 takes into account the generation effect. However, different relationships between the PC1 scores and the hyperbranched mass average molecular weights are observed depending on the normalization procedure used. Normalization of data set ion intensities by ion intensities from the core molecule allows linearization of the SIMS intensities versus the molecular weight and allows the hyperbranched polymers to be discriminated up to the highest generations. In addition, PCA applied to ToF-SIMS data provides an extended interpretation of the spectra leading to further identification of the correlated mass peaks, such as those of the Bis-MPA repeating unit (terminal, dendritic and linear) and those of the core molecule. Finally, the work presented demonstrates the extreme potential of the static ToF-SIMS and PCA techniques in the analysis of dendritic molecules on solid surfaces.

  • 4. Coullerez, G.
    et al.
    Mathieu, H. J.
    Lundmark, S.
    Malkoch, Michael
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Magnusson, H.
    Hult, Anders
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Cationization of dendritic macromolecule adsorbates on metals studied by time-of-flight secondary ion mass spectrometry2003Ingår i: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 35, nr 8, s. 682-692Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was utilized to study dendritic macromolecules with various architectures, such as dendrons, dendrimers and hyperbranched polyesters prepared from bis-(hydroxymethyl)propionic acid (Bis-MPA) and a series of hyperbranched polyethers based on 3-ethyl-3(hydroxymethyl)oxetane. The measurements were performed on spin-coated thin films of the branched molecules (D) onto silicon, chemically etched copper foil and silver-coated wafers. They showed weak signatures of molecular ions by proton capture (D + H)(+) in the high mass range of the spectra (m/z > 400). On the contrary, cationization of the intact molecules with alkali or transition metal ions such as Na+, Cu+ or Ag+ was observed. High-intensity quasi-molecular ions (D + M)(+) (with M = Na+, Cu+ or Ag+) allowed the studied polymers to be identified. The whole molecular species were observed for Bis-MPA dendrons and dendrimers up to 3000 Da for hydroxyl or acetonide-terminated derivatives. The success of the so-called cationization experiments with metal substrates compared with analysis of molecular adsorbates on silicon is highlighted. The ToF-SIMS sensitivity appeared useful to provide information about the molecular end-groups or to highlight incomplete reaction occurring during some deprotection step of the synthesis. Only uncationized fragments of low masses were detected for the hyperbranched polyesters. This result suggested the effect of molecular asymmetry and/or flattening of the molecules on the substrates, which hampered the molecule lift-off efficiency. Nevertheless, the hyperbranched polyethers were characterized based on the peak distribution of intensities, which allowed estimation of their molecular weight average. This work was intended to illustrate the capabilities of ToF-SIMS to analyse dendritic polymers on surfaces.

  • 5. Imran, S.
    et al.
    Yuan, J.
    Yin, G.
    Ma, Y.
    He, Sailing
    KTH, Skolan för elektro- och systemteknik (EES), Elektroteknisk teori och konstruktion.
    Influence of metal electrodes on c-axis orientation of AlN thin films deposited by DC magnetron sputtering2017Ingår i: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 49, nr 9, s. 885-891Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nanocrystalline aluminum nitride (AlN) thin films were deposited on two types of metallic seed layers on silicon substrates, (111) textured Pt and (110) Mo, by reactive DC magnetron sputtering at low temperature (200 °C). Both textured films of Pt and Mo promote nucleation, thereby improving the crystallinity and epitaxial growth condition for AlN thin films. The deposited films were examined by X-ray diffraction, scanning electron microscopy and atomic force microscopy techniques. The results indicated that the preferred orientation of crystallites greatly depends upon the kinetic energy of the sputtered species (target power) and seed layers used. Furthermore, AlN thin films with c-axis perpendicular to the substrate grew on both types of metal electrodes at all power levels larger than 100 W. By comparing the structural properties and compressive stresses at perfect c-axis orientation conditions, it is evident that AlN films deposited on (110) oriented Mo substrates exhibited superior properties as compared with Pt/Ti seed layers. Furthermore, less values of compressive stresses (−3 GPa) as compared with Pt/Ti substrates (−7.08 GPa) make Mo preferentially better candidate to be employed in the field of suspended Micro/Nano - electromechanical systems (MEMS/NEMS) for piezoelectric devices.

  • 6.
    Judith Cruz, M.
    et al.
    Univ Antofagasta, Dept Chem Engn & Mineral Proc, Antofagasta, Chile.;Univ Antofagasta, Ctr Adv Study Lithium & Ind Minerals CELiMIN, Antofagasta, Chile..
    Makarova, Irina V.
    Belarusian State Technol Univ, Dept Chem Technol Electrochem Prod & Elect Engn M, Minsk, BELARUS.;Lappeenranta Univ Technol, Sch Engn Sci, Dept Separat & Purificat, Skinnarilankatu 34, FI-53850 Lappeenranta, Finland..
    Kharitonov, Dmitry S.
    Belarusian State Technol Univ, Dept Chem Technol Electrochem Prod & Elect Engn M, Minsk, BELARUS.;Polish Acad Sci, Jerzy Haber Inst Catalysis & Surface Chem, Krakow, Poland..
    Dobryden, Illia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Yt- och korrosionsvetenskap.
    Chernik, Alexander A.
    Belarusian State Technol Univ, Dept Chem Technol Electrochem Prod & Elect Engn M, Minsk, BELARUS..
    Grageda, Mario
    Univ Antofagasta, Dept Chem Engn & Mineral Proc, Antofagasta, Chile.;Univ Antofagasta, Ctr Adv Study Lithium & Ind Minerals CELiMIN, Antofagasta, Chile..
    Ushak, Svetlana
    Univ Antofagasta, Dept Chem Engn & Mineral Proc, Antofagasta, Chile.;Univ Antofagasta, Ctr Adv Study Lithium & Ind Minerals CELiMIN, Antofagasta, Chile..
    Corrosion properties of nickel coatings obtained from aqueous and nonaqueous electrolytes2019Ingår i: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 51, nr 9, s. 943-953Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nickel was deposited on a copper substrate from aqueous and nonaqueous ethanol electrolytes. X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy and chronovoltametry, scanning electron microscopy, and atomic force microscopy were used to study the effect of the solvent on the surface and corrosion properties of the Ni coatings formed. Unifom and relatively smooth Ni films were obtained as measured with microscopy techniques. The formation of a passive film in acidic, alkaline, and neutral chloride-containing media was confirmed with X-ray photoelectron spectroscopy. The water-based nickel-plating electrolyte makes it possible to deposit coatings with higher corrosion resistance as compared with coatings deposited from ethanol electrolyte in NaOH and NaCl media. The proposed mechanism of corrosion in a 0.5 M H2SO4 solution involves cycles of active-passive surface behavior due to its passivation by corrosion products.

  • 7. Lindström, Rakel
    et al.
    Maurice, V.
    Zanna, S.
    Klein, L.
    Groult, H.
    Perrigaud, L.
    Cohen, C.
    Marcus, P.
    Thin films of vanadium oxide grown on vanadium metal: oxidation conditions to produce V2O5 films for Li-intercalation applications and characterisation by XPS, AFM, RBS/NRA2006Ingår i: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 38, nr 1, s. 6-18Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thin films of vanadium oxide were grown on vanadium metal surfaces W in air at ambient conditions, (ii) in 5 mm H2SO4 (aq), pH 3, (iii) by thermal oxidation at low oxygen pressure (10(-5) mbar) at temperatures between 350 and 550 degrees C and (iv) at near-atmospheric oxygen pressure (750 mbar) at 500 degrees C. The oxide films were investigated by atomic force microscopy (AIM), X-ray photoelectron spectroscopy (XPS), X-Ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA). The lithium intercalation properties were studied by cyclic voltammetry (CV). The results show that the oxide films formed in air at room temperature (RT), in acidic aqueous solution, and at low oxygen pressure at elevated temperatures are composed Of V2O3. In air and in aqueous solution at RT, the oxide films are ultra-thin and hydroxylated. At 500 degrees C, nearly atmospheric oxygen pressure is required to form crystalline V2O5 films. The oxide films grown at pO(2) = 750 mbar for 5 min are about 260-nm thick, and consist of a 115-nm outer layer of crystalline V2O5. The inner oxide is mainly composed Of VO2. For all high temperature oxidations, the oxygen diffusion from the oxide film into the metal matrix was considerable. The oxygen saturation of the metal at 450 degrees C was found, by XPS, to be 27 at.% at the oxide/metal interface. The well-crystallized V2O5 film, formed by oxidation for 5 min at 500 degrees C and 750 mbar O-2, was shown to have good lithium intercalation properties and is a promising candidate as electrode material in lithium batteries.

  • 8. Olander, B.
    et al.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Evaluation of surface modification processes using a ternary XPS diagram2002Ingår i: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 33, nr 7, s. 541-544Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of a ternary XPS diagram to follow surface modification processes involving three elements is described. The elemental composition is represented by a single data point on a plane instead of by two or three elemental ratios or percentages. Vectors are defined between the data points, and simple vector algebra is used to interpret the results. The extent of the surface change is determined by calculating the length of the vector from untreated to a treated composition point, and this leads to a value for the overall change in elemental composition. The direction of the vector indicates how the changes in the individual elemental percentages are related to each other, i.e. what elemental composition the surface is approaching. The ternary XPS diagram is demonstrated and compared with elemental percentages and ratios using XPS data from hydrogen microwave plasma-treated polydimethylsiloxane.

  • 9. Siddle, A.
    et al.
    Castle, J. E.
    Hultquist, Gunnar
    KTH, Tidigare Institutioner                               , Materialvetenskap.
    Tan, K. L.
    Investigation of the initial reaction of the alloy Co86Cr14 and its constituent metals with oxygen using secondary ion mass spectrometry2002Ingår i: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 33, nr 11-okt, s. 807-814Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The initial oxidation of Co86Cr14 and its constituent metals is investigated using an in situ dynamic secondary ion mass spectrometry (SIMS) technique. Simultaneous analysis and controlled formation of oxidation products, rather than just analysis, allows the oxidation to be studied at the very early stages of the process, i.e. when the oxidation product is of submonolayer extent. The technique, initiated by Hultquist(5-7) for the study of pure metals in various in situ environments, involves exposing a sputter-cleaned sample to various partial pressures of oxygen in the SIMS chamber and achieving an equilibrium between the formation and removal of the reaction products under the normal dynamic SIMS conditions. Here, the study is extended to give some insight into the interpretation of the SIMS data obtained by this method, and to determine a model for the oxidation of materials. An empirical model is derived for the oxidation of cobalt. A theoretical model is also derived based on the Langmuir model, but allowing for the more energetic nature of ion bombardment and oxide removal. The theoretical and empirical models are indistinguishable at low oxygen pressures. The cobalt component in the alloy Co86Cr14 behaves in a similar way to that of the pure metal, which suggests that the cobalt oxidizes independently of the chromium in the alloy.

  • 10. Van Gils, S.
    et al.
    Holten, S.
    Stijns, E.
    Vancaldenhoven, M.
    Terryn, H.
    Mattsson, Lars
    KTH, Tidigare Institutioner                               , Industriell produktion.
    Electropolishing of aluminium: processing and assessment of visual appearance2003Ingår i: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 35, nr 2, s. 121-127Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The process of electropolishing aluminium and its influence on the visual appearance are studied. Angle-resolved scattering (ARS) and total integrated scattering (TIS) are used to investigate the influence of electropolishing on surface roughness. The ARS apparatus is built similar to the ASTM E430-97A standard. This standard test method is used for measurement of distinctness of image and haze by goniophotometry. These visual appearance parameters, together with TIS, reflect the changes in surface roughness. Total reflectance is correlated to the composition of the aluminium as well as the composition and thickness of the layer formed on the aluminium.

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