| 1. |
- Bergsåker, Henric, et al.
(författare)
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Ion beam analysis of sputter-deposited gold films for quartz resonators
- 2000
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Ingår i: Surface and Interface Analysis. - 0142-2421 .- 1096-9918. ; 30:1, s. 620-622
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- ANDERSSON, MARCUS, 1976, et al.
(författare)
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Comparison of early stages of precipitation in Mo-rich and Mo-poor maraging stainless steels
- 2007
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Ingår i: Surface and Interface Analysis. - : Wiley. - 1096-9918 .- 0142-2421. ; 39:2-3, s. 195-200
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Tidskriftsartikel (refereegranskat)abstract
- The precipitation process during ageing in the Mo-poor alloy Carpenter 455 has been investigated by three-dimensional atom probe (3DAP) and energy-filtered transmission electron microscopy. The ageing treatment was performed at 475 degrees C for 5 min, 25 min, 1 h and 2 h. The precipitation of a mixed Ni-, Ti- and Cu-rich phase was observed after 25 min of ageing. A complete separation between Ni/Ti-rich and Cu-rich regions occurred within 1-2 h of ageing. After 2 h of ageing at 475 degrees C, coarsening of the eta-Ni3Ti precipitates was observed. Moreover, large Ni/Ti-rich and Cu-rich particles were observed in the lath boundaries after 2 h of ageing. The results were compared with the precipitation process in the Mo-rich alloy 1RK91. Copyright (C) 2007 John Wiley & Sons, Ltd.
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| 3. |
- Andersson, Per Ola, et al.
(författare)
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A novel ATR-FTIR method for functionalised surface characterisation
- 2008
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Ingår i: Surface and Interface Analysis. - : Wiley. - 0142-2421 .- 1096-9918. ; 40:3-4, s. 623-626
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a novel method to analyse ex situ prepared chips by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), which circumvents tedious functionalisation steps of internal reflection elements (IREs), and simultaneously allows for complementary measurements by other analytical techniques. This concept is proved by utilising immobilised metal affinity capture (IMAC) chips containing about 10 gm thick films of copolymers coated with nitrilotriacetic acid (NTA) groups. With this so-called 'upside-down' ATR-FTIR technique, each chemical modification step can be followed and optimised with respect to concentration, buffer, pH, ionic strength, and so on, and there are no limitations in variations or numbers of functionalised surfaces that can be generated. We have demonstrated the feasibility of this approach to determine the molecular structure of ligand bonded to immobilised polypeptide, directly observed in the raw ATR-FTIR spectrum. Peptide adsorption in a thick NTA-copolymer matrix yields a high peptide concentration as determined by the analysis of the Langmuir adsorption isotherm. Combined with the 'upside-down' ATR-FTIR approach which samples the outermost region of the exposed NTA-copolymer film, this generates well-resolved amide I and II absorption bands that reduce the necessity of using D2O based buffers, which otherwise is common in mid-IR spectroscopy of proteins. We believe that this new optical surface characterisation method has a great potential as a stand-alone or complementary analytical tool. We emphasise further that with this approach no chemical treatment of IREs is needed; the chips can be regenerated and reused, and analysed by complementary analytical techniques such as mass spectrometry.
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| 4. |
- Angerer, Tina B., 1987, et al.
(författare)
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3D Imaging of TiO2 nanoparticle accumulation in tetrahymena pyriformis
- 2014
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Ingår i: Surface and Interface Analysis. - : Wiley. - 0142-2421 .- 1096-9918. ; 46:S1, s. 198-203
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Tidskriftsartikel (refereegranskat)abstract
- The increasing use of nanoparticles in a wide range of applications means that there is a significant chance that these chemicals may enter the aquatic environment. We report on the use of time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis to determine the 3D distribution of TiO2 nanoparticles in the fresh water dwelling single cell organism Tetrahymena pyriformis. This organism is a popular model for toxicology studies where assays normally focus on the physical behaviour of the organism (motility, proliferation etc.) or where chemical analysis has been performed on large numbers of cells that have been combined for analysis. SIMS offers the opportunity for studying this single cell organism directly. Using ToF-SIMS analysis, the nanoparticles were shown to be accumulated in food vacuoles approximately 5μm in diameter that are distributed throughout the cell. Challenges associated with accurate 3D reconstruction of the data because of substantial differences in sputter rate between the natural cellular material and the TiO2-rich regions are demonstrated and discussed. © 2014 John Wiley & Sons, Ltd.
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| 5. |
- Armitage, Emily G, et al.
(författare)
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Time-of-flight SIMS as a novel approach to unlocking the hypoxic properties of cancer
- 2013
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Ingår i: Surface and Interface Analysis. - 1096-9918 .- 0142-2421. ; 45:1, s. 282-285
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Tidskriftsartikel (refereegranskat)abstract
- It is known that hypoxia-inducible factor 1 (HIF-1) activity results in the coordinated up-regulation of a large number of proteins that facilitate cell survival in tumours; however, the effect of HIF-1 on cancer metabolism is less well characterised. With knowledge of the specific effect of HIF-1 on cancer metabolism, biomarkers could be identified for which new drugs could be targeted. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) offers the potential to analyse intact cells in situ and has a mass spectral coverage that is applicable to metabolic profiling. It has been used to analyse the effects of HIF-1 on multicellular tumour models. Multicellular tumour spheroids (MTSs) have been cultured from human colon carcinoma cells with and without the expression of HIF-1, and the surface of the cross sections of each MTS has been analysed. Because metabolic profiling is an emerging field in ToF-SIMS, there is a requirement to determine which metabolites can be detected using this technique and which of those can be identified in complex mixtures within biological samples. For this, a selection of metabolites have been analysed, and the ToF-SIMS standard spectra acquired have been used to localise metabolites in MTS sections. The comparison of metabolic profiles of MTSs with and without the expression of HIF-1 has elucidated potential biomarkers for tumour survival in hypoxia, some of which may be HIF-1 regulated.
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| 6. |
- Berger, Robert, et al.
(författare)
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The influence of alkali-degreasing on the chemical composition of hot-dip galvanized steel surfaces
- 2006
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Ingår i: Surface and Interface Analysis. - : Wiley. - 0142-2421 .- 1096-9918. ; 38:7, s. 1130-1138
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Tidskriftsartikel (refereegranskat)abstract
- The influence of dipping temperature and time on the surface chemistry of hot-dipped galvanized steel sheets during the alkaline degreasing process is investigated. The surface chemistry was monitored with scanning Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectroscopy (ToF-SIMS). The results show high Al concentrations on the untreated surfaces, which are significantly reduced during alkaline degreasing. The same conclusions could be drawn for the carbon compounds that accumulate on the surface during storage. The measurements reveal a gradual reduction in surface Al as the alkali solution temperature and/or degreasing time are increased. When degreasing was conducted at 70 °C for 30 s the surface was practically free from Al, which was present only in small islands. Furthermore, the experiments showed that the thickness of the oxide film covering the surfaces before and after alkaline degreasing is approximately 20 Å. The main constituents of the film varied from ZnAl hydroxide/oxide to Zn hydroxide/oxide, before and after degreasing, respectively.
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| 7. |
- Bexell, Ulf, et al.
(författare)
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Characterisation of a Non-Organofunctional Silane Film Deposited on Al, Zn and Al-43.4Zn-1.6Si Alloy-Coated Steel, Part I. Surface Characterization by ToF-SIMS
- 2001
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Ingår i: Surface and Interface Analysis. - 0142-2421 .- 1096-9918. ; 31:3, s. 212-222
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Tidskriftsartikel (refereegranskat)abstract
- The need to develop new environmentally friendly pretreatments in the surface engineering of metal substrates has become more and more important.This is mainly due to the toxic and carcinogenic properties of the chromium-based surface pretreatments frequently used in the industry. During the last decade, simple solution-dip silane-based pretreatments have emerged as promising candidates for the replacement of currently used pretreatments of metals. Recent investigations have shown that the performance of these newly developed pretreatments is strongly dependent on the chemical composition and structure of the silane film and consequently a lot of work, based on advanced surface analytical techniques, is needed in order to characterize these properties. In the present study, time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been used to characterize the structure of thin films of the non-organofunctional silane 1,2-bis(triethoxysilyl)ethane (BTSE) deposited on three different metal substrates, i.e. Al, Zn and Al-43.4Zn-1.6Si (AlZn) alloy-coated steel. Of special interest was an evaluation of the influence of substrate material on the structure and composition of the silane films. The results show that the BTSE silane forms a thin, evenly distributed film over the substrate surfaces and that the molecular structure of the silane film is independent of the type of metal substrate. Analysis of the molecular ions in the positive mode shows that the surface structure of the BTSE silane is very complex and that the BTSE condensates via one to three SiOSi bridges. Also, the results show that the BTSE silane is not fully hydrolysed using a hydrolysing time of 1 h. Finally, if an alcohol is used as a solvent for the BTSE there is a clear chemical interaction between the alcohol and the silane, resulting in an exchange of alkoxy groups between the alcohol and the silane. Copyright © 2001 John Wiley & Sons, Ltd.
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| 8. |
- Bexell, Ulf, et al.
(författare)
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Characterisation of a Non-Organofunctional Silane Film Deposited on Al, Zn and Al-43.4Zn-1.6Si Alloy Coated Steel, Part II. Interfacial Characterization by ToF-SIMS and AES
- 2001
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Ingår i: Surface and Interface Analysis. - 0142-2421 .- 1096-9918. ; 31:3, s. 223-231
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Tidskriftsartikel (refereegranskat)abstract
- Time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been used to analyse the interface between a non-organofunctional silane and three different metal substrates (aluminium, zinc and an aluminium-zinc alloy). Ion etching using Ga+ ions was used to expose the interfacial region. Ion fragments from the samples were examined carefully where supposed metal-oxygen-silicon ion fragments should appear in the mass spectra. From high mass resolution spectra it was concluded that there exists an AlOSi+ ion fragment at nominal mass m/z = 71 amu on the aluminium and aluminium-zinc alloy substrates and a ZnOSi+ ion fragment at nominal mass m/z = 108 amu on the zinc and aluminium-zinc alloy substrates. These results are further enhanced by the fact that the characteristic ion pattern of ZnOSi+-type ion fragments, composed of different naturally stable zinc and silicon isotopes, in the mass range m/z = 108-112 amu showed the expected relative peak height relations. The presence of these metal-oxygen-silicon ion fragments is a strong indication that chemical interaction between the silane and the metal substrates exists and that the nature of this interaction is due to the formation of a covalent bond between the silane and the metal substrate. Copyright © 2001 John Wiley & Sons, Ltd.
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