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| 2. |
- Ohlsson, B. J., et al.
(författare)
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Size-, shape-, and position-controlled GaAs nano-whiskers
- 2001
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 79:20, s. 3335-3337
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a technique for the synthesis of size-selected, GaAs, epitaxial nano-whiskers, grown on a crystalline substrate. As catalysts, we used size-selected gold aerosol particles, which enabled us to fully vary the surface coverage independently of the whisker diameter. The whiskers were rod shaped, with a uniform diameter between 10 and 50 nm, correlated to the size of the catalytic seed. Furthermore, by the use of nano-manipulation of the aerosol particles by means of atomic force microscopy, we can nucleate individual nano-whiskers in a controlled manner at specific positions on a substrate with accuracy on the nm level.
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| 3. |
- Berg, LK, et al.
(författare)
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GP-zones in Al-Zn-Mg alloys and their role in artificial aging
- 2001
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Ingår i: Acta Materialia. - 1359-6454. ; 49:17, s. 3443-3451
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Tidskriftsartikel (refereegranskat)abstract
- The structure of GP-zones in an industrial, 7xxx-series Al–Zn–Mg alloy has been investigated by transmission electron microscopy methods: selected area diffraction, conventional and high-resolution imaging. Two types of GP-zones, GP(I) and (II) are characterized by their electron diffraction patterns. GP(I)-zones are formed over a wide temperature range, from room temperature to 140–150°C, independently of quenching temperature. The GP(I)-zones are coherent with the aluminum matrix, with internal ordering of Zn and Al/Mg on the matrix lattice, suggested to be based on AuCu(I)-type sub-unit, and anti-phase boundaries. GP(II) are formed after quenching from temperatures above 450°C, by aging at temperatures above 70°C. The GP(II)-zones are described as zinc-rich layers on {111}-planes, with internal order in the form of elongated domains. The structural relation to the η′-precipitate is discussed.
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Dillier, N, et al.
(författare)
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Measurement of the electrically evoked compound action potential via a neural response telemetry system
- 2002
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Ingår i: Annals of Otology, Rhinology & Laryngology. - 0003-4894. ; 111:5, s. 407-414
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Tidskriftsartikel (refereegranskat)abstract
- The main aim of this study was to validate a new technique, neural response telemetry (NRT), for measuring the electrically evoked compound action potential in adult cochlear implant users via their Nucleus CI24M implant. Thirty-eight adults were evaluated with a variety of measurement procedures with the NRT software. Electrically evoked compound action potentials were obtained in 31 of the 38 adults (81.6%) and in 132 of the 160 electrodes (82.5%) tested. In addition to validating this technique, We also established a set of default clinical test parameters.
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| 8. |
- Jensen, K V, et al.
(författare)
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Effect of impurities on structural and electrochemical properties of the Ni-YSZ interface.
- 2003
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Ingår i: Solid State Ionics. - 0167-2738. ; 160:1-2, s. 27-37
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Tidskriftsartikel (refereegranskat)abstract
- The changes in interface structure and chemical composition of a 99.995% pure nickel/yttria-stabilised zirconia (YSZ) interface were examined after heat treatment at 1000 °C in 97% H2/3% H2O with and without polarisation. Impedance spectroscopy was used for electrochemical characterisation. The results were compared to earlier investigations of a less pure nickel/YSZ interface. The pure interface developed different structures depending on whether or not the samples were polarised. Despite the purity of the nickel, impurities were found in the interfacial region. The pure electrodes/interfaces showed area specific polarisation resistances 10 times lower than the impure interfaces.
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| 9. |
- Kallioinen, J, et al.
(författare)
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Photoinduced ultrafast dynamics of Ru(dcbpy)(2)(NCS)(2)-sensitized nanocrystalline TiO2 films: The influence of sample preparation and experimental conditions
- 2004
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Ingår i: The Journal of Physical Chemistry Part B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 108:20, s. 6365-6373
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Tidskriftsartikel (refereegranskat)abstract
- In most of the previous ultrafast electron injection studies of Ru(dcbpy)(2)(NCS)(2)-sensitized nanocrystalline TiO2 films, experimental conditions and sample preparation have been different from study to study and no studies of how the differences affect the observed dynamics have been reported. In the present paper, we have investigated the influence of such modifications. Pump photon density, environment of the sensitized film (solvent and air), and parameters of the film preparation (crystallinity and quality of the film) were varied in a systematic way and the obtained dynamics were compared to that of a well-defined reference sample: Ru(dcbpy)(2)(NCS)(2)-TiO2 in acetonitrile. In some cases, the induced changes in the dynamics were uncorrelated to the electron injection process. High pump photon density (not in the linear response region) and exposure of the sensitized film to air altered the picosecond-time- scale kinetics considerably, and the changes were attributed mostly to degradation of the dye. In other cases, changes in the measured kinetics were related to the electron injection processes: reducing the firing temperature of the nanocrystalline film or making the film via electron beam evaporation (EBE) resulted in a decrease of the overall crystallinity of the film, and the electron injection slowed. In the sensitized EBE films, in addition to an increased contribution of triplet excited-state electron injection, a new electron transfer (ET) process with a time constant of 200 fs was observed.
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| 10. |
- Oku, T, et al.
(författare)
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Modulated structure of Ag2SnO3 studied by high-resolution electron microscopy
- 2000
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Ingår i: Acta Crystallographica. Section B: Structural Science. - 0108-7681. ; 56:3, s. 363-368
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Tidskriftsartikel (refereegranskat)abstract
- The modulated structure of Ag2SnO3, disilver tin trioxide, was investigated by high-resolution electron microscopy and electron diffraction along four different directions. Electron diffraction showed an incommensurate one-dimensional modulated structure with a modulation wavevector of 1/6.4a*. High-resolution images showed a large number of superstructure domains with the size range 10-100 nm and orientations related by hexagonal rotation. The modulation was determined to be displacements along the c axis of the Ag atoms both in octahedral and linear coordination. An approximate structure model with a commensurate sixfold superstructure, with an orthorhombic cell (P2(1)2(1)2(1), a = 2.922, b = 1.267, c = 0.562 nm), is proposed. Calculated images and electron diffraction patterns, based on this model, agree well with experimental observations.
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