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  • 1.
    Berger, Erik
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi.
    Structure of a hepta-nuclear termetallic oxo-alkoxide: Eu3K3TiO2(OBut)11(OMe/OH)(HOBut)2010Inngår i: Journal of Sol-Gel Science and Technology, ISSN 0928-0707, E-ISSN 1573-4846, Vol. 53, nr 3, s. 681-688Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The novel termetallic oxo-methoxo-tert-butoxide Eu3K3TiO2(OBut)11(OMe/OH)(HOBut) (1) has been synthesised and structurally and spectroscopically characterised. Its unusual structure features an Eu3K3O fac-octahedron, capped by a distorted K3TiO tetrahedron on the K3 face. The compound, crystallising in space group P21/n with cell parameters a = 14.44 Å, b = 23.58 Å, c = 21.27 Å and β = 96.18°, is the result of incomplete metathesis between EuCl3 and potassium and titanium tert-butoxides in combination with deliberate hydrolysis and decomposition. It provides one of few examples of termetallic lanthanide alkoxides, as well as of an alkoxide tert-butyl group decomposing into a methyl group.

  • 2.
    Boström, T
    et al.
    Norut Northern Research Institute Narvik, Norge.
    Valizadeh, Sima
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Lu, J
    Division of Thin Film Physics, Department of Physics, Chemistry and Biology - IFM, Linköping University, Linköping.
    Jensen, J
    Division of Thin Film Physics, Department of Physics, Chemistry and Biology - IFM, Linköping University, Linköping.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Wäckelgård, Ewa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Structure and morphology of nickel-alumina/silica solar thermal selective absorbers2011Inngår i: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 357, nr 5, s. 1370-1375Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nickel-alumina/silica thin film materials for the use in solar thermal absorbers have been investigated using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Elastic Recoil Detection Analysis (ERDA). The TEM images revealed that all layers have a very small thickness variation and that the layers are completely homogenous. High resolution images showed 5-10 nm (poly) crystalline nickel nano-particles. ERDA showed that both the silica and alumina compositions contain more oxygen than 2:1 and 3:2 respectively. SEM showed the surface morphology and characteristics of the top silica anti-reflection layer. Hybrid-silica has showed to generate a smoother surface with less cracking compared to pure silica. The final curing temperature revealed to be of importance for the formation of cracks and the surface morphology.

  • 3.
    Boström, T
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Westin, G
    Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Wäckelgård, E
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Spectrally selective solar thermal absorber based on sol-gel and solution-chemistry methods2005Inngår i: SOLGEL 2005, 2005Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 4.
    Boström, T
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Fasta tillståndets fysik.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Wäckelgård, E
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Durability tests of solution-chemically derived spectrally selective absorbers2005Inngår i: Solar Energy Materials and Solar Cells, Vol. 89, s. 197-207Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A detailed neutron powder diffraction and calorimetric study was conducted to determine the influence of increasing Mn-substitution on the crystal and the magnetic structures of hematite, α-Fe2O3. The study was initiated to determine, if Mn substitution may be responsible for unusual ferromagnetic properties of natural hematite samples from the Kalahari Mn field, South Africa. Natural as well as synthetic Mn-bearing hematite samples with the compositional range Fe2−xMnxO3 (x=0 to 0.176) were examined. Calorimetric measurements were performed to determine the Néel TN and the Morin TM temperature transitions. All studied hematite samples, irrespective of chemical composition, display weak ferromagnetism at 295 K and coexistence of weak ferromagnetic and antiferromagnetic phases at 10 K. A slight decrease of the total magnetic moment and TM but a drastic decrease of TN can be attributed to increasing Mn-substitution. The results illustrate that Mn substitution may contribute but cannot be the sole reason for the unusual magnetic properties of natural hematite samples.

  • 5.
    Boström, T
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Fasta tillståndets fysik.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Wäckelgård, E
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Fasta tillståndets fysik.
    Experimental an theoretical optimization of a three layer solution chemically derived spectrally selective absorber2005Inngår i: ISES 2005, 2005Konferansepaper (Annet vitenskapelig)
  • 6.
    Boström, Tobias
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Jensen, J
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Jonfysik. Jonfysik.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Wäckelgård, Ewa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Accelerated ageing tests of optimized solution chemically derived selective solar thermal absorbers2006Konferansepaper (Fagfellevurdert)
  • 7.
    Boström, Tobias
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi.
    Wäckelgård, Ewa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Optimization of a solution-chemically derived solar absorbing spectrally selective surface2007Inngår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 91, nr 1, s. 38-43Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A previously studied solution chemically derived two layer absorber has been improved by adding a third layer. Simulations done with a thin film program showed that the optimized three layer selective absorber should be composed of an 80% nickel-20% alumina film of 100 nm at the base, a 40% nickel-60% alumina film of 60 nm in the middle and finally a 100% silica film of 85 nm at the top. Experimental results confirmed the computer simulated three layer structure. Prepared absorber consisting of the theoretically found optimized layer structure achieved a solar absorptance, alpha(sol), of 0.97 and a thermal emittance, epsilon(therm), of 0.05.

  • 8.
    Boström, Tobias
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Wäckelgård, Ewa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. oorganisk kemi.
    Anti-reflection coatings for solution-chemically derived nickel—alumina solar absorbers2004Inngår i: Solar Energy Materials & Solar Cells, nr 84, s. 183-191Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to suppress reflections from a solar absorber surface an anti-reflection (AR) layer is usually deposited on top of the solar absorbing coating. For the AR coating to function well it be made of a material with a lower refractive index than the underlying surface. Provided that the AR coating is sufficiently thin, it will not increase the thermal emittance value. Besides increasing the solar absorptance it is equally important that the AR layer is long term stable in order to create a successful solar selective coating. The objective was to create a highly efficient, flexible, inexpensive and durable AR coating for solar absorbers using simple techniques. Elastic properties are requested because it prohibits the formation of micro-cracks.

    Mumina, silica and hybrid silica AR coatings were synthesized using solution chemistry and )l-gel techniques. The AR coatings were deposited on the absorber surface using spin

    coating. The absorbers used without an AR layer had a normal solar absorptance of 0.79-0.81 and a normal thermal emittance of 0.03 The optimum anti-reflection coated sample acquired

    a normal solar absorptance of 0.93 while the thermal emittance remained unaltered. The study has shown that by adding a proper AR coating to a solar absorber the spectral selectivity can be considerably enhanced.

  • 9.
    Boström, Tobias
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Wäckelgård, Ewa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fasta tillståndets fysik.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. oorganisk kemi.
    Solution-chemical derived nickel-alumina coatings for thermal solar absorbers2003Inngår i: Solar Energy, nr 74, s. 497-503Artikkel i tidsskrift (Fagfellevurdert)
  • 10.
    Ekstrand, Åsa
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Jansson, K
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    A Solution Synthetic Route to Nanophase Cobalt Film and Sponge2005Inngår i: Chem. Mater, Vol. 17, s. 199-205Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An efficient, low-cost solution-chemical route to nanophase cobalt as dense films and sponges has been developed. Co(NO3)2·6H2O and Co(OAc)2·4H2O were mixed with triethanolamine in methanol, and the solution was evaporated in air to a viscous liquid. Heating at 10 C min-1 to 470 and 500 C yielded highly porous sponges consisting of 3-6 and 9-11 nm sized face centered cubic (fcc) cobalt crystallites, respectively. Spin-coating on alumina and aluminum substrates with a 1 M Co-precursor solution and subsequent heating at 10 C min-1 to 500 C yielded dense films of <20 nm sized fcc cobalt crystallites. The microstructural and compositional evolution process on heating to form the cobalt metal was studied by TGA, DTA, and FT-IR spectroscopy, powder X-ray diffraction, TEM-EDS, and SEM-EDS. The C, N, and O contents could be kept low, 0.5, 0.02, and 0.2 wt %, respectively, at 700 C, but the carbon content could also reproducibly be adjusted to up to 13 wt % C in excess, by varying the precursor composition.

  • 11.
    Ekstrand, Åsa
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Highly homogeneous WC-Ni/Co Composites Produced from WC-Powder coated with a Solution Chemical Route2002Inngår i: 10th International Ceramics Congress 2002 Proceedings, 2002, s. 489-Konferansepaper (Fagfellevurdert)
  • 12.
    Ekstrand, Åsa
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi.
    Nygren, Mats
    Homogeneous WC–Co-Cemented Carbides from a Cobalt-Coated WC Powder Produced by a Novel Solution-Chemical Route2007Inngår i: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 90, nr 11, s. 3449-3454Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A solution chemical route to cobalt-coated WC-powder is described that allows for the preparation of WC–Co powders and compacts having a carbon content very close to the desired carbon content even under an inert atmosphere. The microstructural homogeneity in the sintered WC–Co composites when using the Co-coated grains was found to be superior as compared with conventionally mill-mixed powders, and the structural changes in the individual WC-grains were found to be much smaller, which is ascribed mainly to the fact that the coated grains do not require a grinding step leading to the formation of a tail of smaller WC grain sizes.

  • 13.
    Ekstrand, Åsa
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Pohl, Annika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Lafton, J
    Solution synthesis of Cobalt-Copper Nano Phase Films and Sponges2005Inngår i: 13:th International Workshop on Gels and Glasses, Los Angeles, 2005, 2005, s. 2-Konferansepaper (Fagfellevurdert)
  • 14. Engholm, M
    et al.
    Lashgari, Koroush
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Edvardsson, S
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Norin, L
    Atomically designed precursors in optical fiber amplifiers: The thermal stability of the heterobimetallic ErAl3(OPri)12 in a solution-coated silica soot2005Inngår i: Journal of Applied Physics, Vol. 97, s. 113104-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The thermal stability of the bimetallic alkoxide ErAl3(OPri)12 doped in an unsintered silica (soot) has been investigated. Samples have been heated to different temperatures (up to 1500 °C and analyzed by using ultraviolet-visible-near infrared absorption spectroscopy, infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, thermal gravimetric analysis, and powder x-ray diffraction. It is seen that the doped samples heated up to 1000 °C show broad glasslike absorption spectra, indicating an amorphous structure, while the high-temperature sample shows an ordered crystallinelike structure with sharp characteristic absorption peaks. X-ray diffraction measurements indicate the formation of an ordered structure at temperatures of 1500 °C, revealing a crystal phase of silica and phases of erbium and aluminosilicate. A comparison is also made with a sample doped with aqueous ErCl3 and Al(NO3)3. It is concluded that the local structure of the ErAl3 precursor is not preserved at temperatures above 1000 °C. Alternative doping procedures are discussed.

  • 15. Engholm, M.
    et al.
    Norin, L.
    Edvardsson, S.
    Lashgari, K.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    A structural investigation of a synthesized precursor for optical fiber applications: the heterobimetallic ErNb2(OPri)(13)2006Inngår i: Optical materials (Amsterdam), ISSN 0925-3467, E-ISSN 1873-1252, Vol. 29, nr 4, s. 386-391Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A structural investigation of a synthesized precursor in a silica glass matrix is performed. Silica soot samples are doped with the heterobimetallic precursor ErNb2(OPri)13 by using a conventional solution doping technique and heat treatments to different temperatures. The precursor has also been introduced into a silica fiber preform by using the modified chemical vapor deposition technique. Analyses are made by using ultraviolet–visible–near infrared absorption spectroscopy, scanning electron microscopy, energy dispersive spectroscopy and powder X-ray diffraction. It is concluded that an immiscible system of ErNbO4 crystallites and Nb2O5 is formed in the silica soot samples at high temperatures. Colloidal particles of ErNbO4 are also formed in the silica glass fiber preform showing interesting features.

  • 16. Fors, Rickard
    et al.
    Khartsev, Sergey
    Grishin, Alexander
    Pohl, Annika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Sol-gel derived versus pulsed laser deposited epitaxial La0.67Ca0.33MnO3 films: structure, transport and effects of post-annealing2004Inngår i: Thin Solid Films, nr 467, s. 112-116Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Epitaxial La0.67Ca0.33MnO3 films have been prepared on LaAl03 crystals by pulsed laser deposition (PLD) and by a novel all-alkoxide sol-gel technique. Different out-of-plane lattice parameters are found for the as-prepared films, and scanning electron microscopy shows a more porous structure for sol-gel films as compared to PLD films. These differences are largely removed by post annealing at 1000 °C. ) Transport measurements show maximum temperature coefficient of resistivity of 8.2% K-1 at 258 K (PLD) and 6.1% K-1 at 241 K (sol-gel) and colossal magnetoresistance at 560 kA/m of 35% at 263 K (PLD) and 32% at 246 K (sol-gel).

  • 17. Fors, Rickard
    et al.
    Pohl, Annika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Khartsev, Sergey
    Grishin, Alexander
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Comparison of Sol-Gel Derived and Pulsed Laser Deposited Epitaxial La0.67Ca0.33MnO3 Films for IR Bolometer2004Inngår i: Mat. Res. Soc. Symp. Proc., Vol. 811, s. E2.5.1-E2.5.6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Epitaxial La0.67Ca0.33MnO3 films have been prepared on LaA1O3 crystals by pulsed laser deposition (PLD) and by a novel all-alkoxide sol-gel technique. Different out-of-plane lattice parameters are found for the as-prepared films, and scanning electron microscopy shows a more porous structure for sol-gel films as compared to PLD films. These differences are largely removed by post-annealing at 1000 °C. Transport measurements show maximum temperature coefficient of resistivity of 8.2 % K-1 at 258 K (PLD) and 6.1 % K-1 at 241 K (sol-gel) and :colossal magnetoresistance at 7 kOe of 35 % at 263 K (PLD) and 32 % at 246 K (sol-gel).

  • 18. Jansson, K.
    et al.
    Nygren, M.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Preparation of nano-sized LaYO3 powder, and studies of pressureless and spark plasma sintering2002Inngår i: 10th International Ceramics Congress 2002 Proceedings, 2002, s. 131-Konferansepaper (Fagfellevurdert)
  • 19. Jansson, K
    et al.
    Pohl, Annika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Ekstrand, Åsa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Formation of nano-sized Ni, Cu and Ni-Cu-alloy particles in a matrix of amorphous Al2O32001Inngår i: SCANDEM, s. 176-177Artikkel i tidsskrift (Fagfellevurdert)
  • 20. Jansson, K
    et al.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    An aqueous synthesis route to new catalyst material for car exhaust purification2005Inngår i: 13:th International Workshop on Gels and Glasses, Los Angeles, 2005, 2005, s. 2-Konferansepaper (Fagfellevurdert)
  • 21. Jansson, K
    et al.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Characterisation of Pd and Pt catalysts supported on a wash coat of nano-sized LaYO3- A new catalyst for car exhausts2001Inngår i: SCANDEM, s. 174-175Artikkel i tidsskrift (Fagfellevurdert)
  • 22.
    Katea, Sarmad Naim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Hajduk, Spela
    Natl Inst Chem, Hajdrihova 19, SI-1001 Ljubljana, Slovenia.
    Orel, Zorica Crnjak
    Natl Inst Chem, Hajdrihova 19, SI-1001 Ljubljana, Slovenia.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Low Cost, Fast Solution Synthesis of 3D Framework ZnONanosponges2017Inngår i: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 56, nr 24, s. 15150-15158Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An efficient, template-free solution-chemical route to nanostructured ZnO sponges is presented: A mixture of Zn(NO3)(2)center dot 6H(2)O, Zn(OAc)(2).2H(2)O, and triethanolamine in methanol was evaporated to a highly viscous liquid and rapidly heated to >200 degrees C for 1-3 min to achieve highly porous, nanocrystalline sponges of ZnO. The viscous precursor concentrate obtained on evaporation in air was characterized by TG, DSC, and IR spectroscopy, and the product ZnO sponges by XRD, SEM, TEM, and IR spectroscopy. The fast reaction forming ZnO started at 140 degrees C and finished within a few seconds. Scherrer analysis of the XRD peak broadening showed average crystallite sizes of 8 to 11 nm for ZnO prepared by annealing at 200-450 degrees C (3 min), while grain growth to 134 nm was observed from 500 to 900 degrees C (3 min). The ZnO powders obtained at 200-900 degrees C had cell dimensions of a = 3.25 angstrom and b = 5.21 angstrom, matching the ZnO literature data well. SEM and TEM analyses showed highly porous, bread-like 3D nanostructures built by ca. 30-70 nm thick walls of ZnO crystallites of the approximate average sizes given by the XRD Scherrer analysis. It seems that the crystal growth above 450 degrees C takes place within the ZnO 3D structure obtained at lower temperatures without much sintering of the larger porous structure.

  • 23. Katumba, G
    et al.
    Lu, J
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fysiska sektionen, Institutionen för fysik och materialvetenskap, Experimentell fysik.
    Olumekor, L
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fysiska sektionen, Institutionen för fysik och materialvetenskap, Experimentell fysik. oorganisk kemi.
    Wäckelgård, E
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik. Fysiska sektionen, Institutionen för fysik och materialvetenskap, Experimentell fysik. Fasta tillståndets fysik.
    Low Cost Selective Solar Absorber Coatings: Characteristics of Carbon-In-Silica Synthesized with Sol-Gel Technique2005Inngår i: Journal of Sol-Gel Science and Technology, ISSN 0928-0707 (Paper) 1573-4846 (Online), Vol. 36, s. 33-43Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Carbon-silica composite films have been fabricated using sol-gel synthesis of silica-carbon precursor composites, followed by carbonization in an inert atmosphere. Four categories of samples were studied. These were the tetraethyl orthosilicate-only (TEOS-only), methyl trimethoxysilane (MTES), acetic acid anhydride (Ac2O) and soot (SOOT) samples. The carbon-silica films, spin-coated on aluminium and steel substrates, have been investigated for selective solar absorber functionality. Optical measurements were performed on these samples to determine solar absorptance and thermal emittance of each. The morphology of the films was studied by electron microscopy. Electron energy-loss spectroscopy (EELS) mapping was used to determine the carbon distribution. An optimum performance of 0.88 for solar absorptance and 0.41 for thermal emittance has been achieved. The sol-gel technique produced films with very flat surfaces and uniform thicknesses in the 1 μm range. The fine structure showed homogeneous mixing of the carbon and silica in the TEOS-only samples while the separate additions of MTES and Ac2O resulted in segregation of composition of the silica and carbon at nano-scale. The addition of 20 wt% MTES or 15 wt% Ac2O to the TEOS-only sols also helped to reduce the cracks in the TEOS-only samples. The addition of soot in place of the carbon precursor did not yield a net advantage.

  • 24.
    Knut, Ronny
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Yt- och gränsskiktsvetenskap.
    Wikberg, J. Magnus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Lashgari, Koroush
    Coleman, Victoria A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Svedlindh, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Karis, Olof
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Yt- och gränsskiktsvetenskap.
    Magnetic and electronic characterization of highly Co-doped ZnO: An annealing study at the solubility limit2010Inngår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 82, nr 9, s. 094438-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on investigations of the electronic structure and magnetic properties of ZnO doped with 15 at. % Co and postgrowth annealed at temperatures ranging between 250 and 800°C. In particular, we demonstrate how the presence of Co3+, indicative of secondary phases, is manifested in spectroscopy. Through resonant photoemmision spectroscopy we have found that x-ray diffraction in some cases underestimates or does not reveal the presence of secondary phases, possibly due to unrelaxed structures or structural arrangements with sizes below the detection limit. The magnetic properties are in most cases understood by assuming small antiferromagnetic clusters but can also show a behavior indicative of ferromagnetic interactions.

  • 25.
    Kritikos, M
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Moustiakimov, M
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Wijk, M
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Synthesis, structure and characterisation of Ln(5)O(OPri)(13) with Ln = Nd, Gd or Er2001Inngår i: JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS, ISSN 1472-7773, nr 13, s. 1931-1938Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The molecular and basically isostructural oxo-alkoxides Ln(5)O(OPri)(13) (Pr-i = 2-propyl) with Ln = Nd (1) and Gd (2) were synthesized by metathesis of LnCl(3) and KOPri, in combination with stoichiometric hydrolysis, in 2-propanol-containing solvents. E

  • 26. Kritikos, Mikael
    et al.
    Moustiakimov, Marat
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Synthesis, structure and properties of two unexpected square pyramidal pentanuclear oxo-isopropoxide molecules: Ce5O(OPri)13 and La5O(OPri)13(HOPri)22012Inngår i: Inorganica Chimica Acta, ISSN 0020-1693, E-ISSN 1873-3255, Vol. 384, s. 125-132Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The synthesis, structure and properties of two pentanuclear oxo-alkoxides are described. A combination of metathesis of LnCl(3) and 3KOPr(i) and stoichiometric hydrolysis resulted in the solvated oxo-alkoxide La5O(OPri)(13)(HOPri)(2) (1) and the non-solvated Ce5O(OPri)(13) (3). 1 is rather stable at room-temperature, but desolvation into La5O(OPri)(13) (2), identified by spectroscopy, could be achieved by vacuum treatment. 1 and 3 were structurally characterised by single-crystal X-ray diffraction. In both 1 and 3 the metal atoms have a square pyramidal arrangement. In 1, each crystallographically independent La5O(OPri)(13) (HOPri)(2) molecule contains 3 six-coordinated and 2 seven-coordinated La atoms, while in 3 all Ce atoms are six-coordinated. 3 Is the first structurally characterized example of a purely Ce3+ isopropoxide. Characterisations of 1 and 3 were by IR- and Raman spectroscopy and differential scanning calorimetry, and for 1 also by H-1 and C-13 NMR spectroscopy. The great similarity of the IR spectra of the solid 1 and 3, respectively, to their corresponding solutions, showed that the molecular structure present in the solid state is close to retained in solution.

  • 27. Kritikos, Mikael
    et al.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Synthesis, Structure and Properties of ErNb2(OPri)132004Inngår i: Journal of Sol-Gel Science and Technology, Vol. 32, s. 25-29Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The molecular alkoxide, ErNb2(OPri)13 was prepared by metathesis with 2KNb(OPri)6, KOPri and ErCl3, and structurally determined by single-crystal X-ray diffraction techniques. Each molecule contains a central Er3+-ion coordinates by six OPri groups placed, one via a double alkoxo-bridge and the other via a triple alkoxo.bridge. It is isostructural with LaNb2(OPri)13, in spite of the large difference in ionic radius between Er3+ and La3+ (16%). The compound was characterized by its IR- and UV-vis-NIR-spectroscopic fine structures, and found to be structurally intact in hexane:isopropanol solution.

  • 28. Kronawitter, C. X.
    et al.
    Zegkinoglou, I.
    Shen, S. -H
    Liao, P.
    Cho, I. S.
    Zandi, O.
    Liu, Y. -S
    Lashgari, Koroush
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Guo, J. -H
    Himpsel, F. J.
    Carter, E. A.
    Zheng, X. L.
    Hamann, T. W.
    Koel, B. E.
    Mao, S. S.
    Vayssieres, L.
    Titanium incorporation into hematite photoelectrodes: theoretical considerations and experimental observations2014Inngår i: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 7, nr 10, s. 3100-3121Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A theoretical and experimental perspective on the role of titanium impurities in hematite (alpha-Fe2O3) nanostructured photoelectrodes for solar fuel synthesis devices is provided. Titanium incorporation is a known correlate to efficiency enhancement in alpha-Fe2O3 cc photoanodes for solar water oxidation; here the relevant literature and the latest advances are presented and various proposed mechanisms for enhancement are contrasted. Available experimental evidence suggests that Ti incorporation increases net electron carrier concentrations in electrodes, most likely to the extent that (synthesis-dependent) charge compensating cation vacancies are not present. However, electron conductivity increases alone cannot quantitatively account for the large associated photoelectrochemical performance enhancements. The magnitudes of the effects of Ti incorporation on electronic and magnetic properties appear to be highly synthesis-dependent, which has made difficult the development of consistent and general mechanisms explaining experimental and theoretical observations. In this context, we consider how the electronic structure correlates with Ti impurity incorporation in alpha-Fe2O3 a from the perspective of synchrotron-based soft X-ray absorption spectroscopy measurements. Measurements are performed on sets of electrodes fabricated by five relevant and unrelated chemical and physical techniques. The effects of titanium impurities are reflected in the electronic structure through several universally observed spectral characteristics, irrespective of the synthesis techniques. Absorption spectra at the oxygen K-edge show that Ti incorporation is associated with new oxygen 2p-hybridized states, overlapping with and distorting the known unoccupied Fe 3d-O 2xp band of alpha-Fe2O3. This is an indication of mixing of Ti s and d states in the conduction band of alpha-Fe2O3. cc A comparison of spectra obtained with electron and photon detection shows that the effects of Ti incorporation on the conduction band are more pronounced in the near-surface region. Titanium L-2,L-3-edge absorption spectra show that titanium is incorporated into alpha-Fe2O3 as Ti4+ by all fabrication methods, with no long-range titania order detected. Iron L-2,L-3-edge absorption spectra indicate that Ti incorporation is not associated with the formation, of any significant concentrations of Fe2+, an observation common to many prior studies on this material system.

  • 29.
    Lashgari, Koroush
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Preparation of PZT Film on Conducting Ceramic Electrodes using Ti- and Zr-Alkoxides and Pb(NO3)2(EO3)1.52002Inngår i: 10th Internaitonal Ceramics Congress 2002 Proceedings, 2002, s. 517-Konferansepaper (Fagfellevurdert)
  • 30. Lima, Nicola
    et al.
    Caneschi, Andrea
    Gatteschi, Dante
    Kritikos, Mikael
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Validity of the Classical Monte Carlo Method To Model the Magnetic Properties of a Large Transition-Metal Cluster: Mn192006Inngår i: Inorganic Chemistry, Vol. 45, nr 6, s. 2391-2393Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The susceptibility of the large transition-metal cluster [Mn19O12(MOE)14(MOEH)10]·MOEH (MOE = OC2H2O-CH3) has been fitted through classical Monte Carlo simulation, and an estimation of the exchange coupling constants has been done. With these results, it has been possible to perform a full-matrix diagonalization of the cluster core, which was used to provide information on the nature of the low-lying levels.

  • 31.
    Lindberg, Daniel
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Åkerström, Göran
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Westin, Gunnar
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Evaluation of CDKN2C/p18, CDKN1B/p27, and CDKN2B/p15 mRNA expression and CpG methylation status in sporadic and MEN1-associated pancreatic endocrine tumors2008Inngår i: Clinical Endocrinology, ISSN 0300-0664, E-ISSN 1365-2265, Vol. 68, nr 2, s. 271-278Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective Menin, encoded by the multiple endocrine neoplasia type 1 (MEN1) gene at 11q13, enhances transcription of the cyclin-dependent kinase inhibitors (CDIs), CDKN2C (p18) and CDKN1B (p27) in mouse pancreatic islets, and inactivation of menin reduced CDKN2B (p15) expression in this mouse model. Here, we have compared the relative mRNA expression level and CpG methylation status of p18, p27 and p15 in 18 pancreatic endocrine tumours (PETs) with or without MEN1 gene mutations. Design Real-time quantitative PCR, DNA sequencing and pyro-sequencing methylation analysis were employed. Results The p18 gene was expressed in 15 out of the 18 analysed PETs. The expression level was within the range of the normal pancreatic tissues or higher. Of the three remaining tumours with no expression, two displayed loss of heterozygocity (LOH) at 11q13, one derived from a MEN1 patient. The p27 gene was expressed in all PETs at a level higher than the normal pancreatic tissues, except for one tumour. Promoter methylation was not detected for p18 and p27. p15 expression was undetectable in 8/18 (44%) of the PETs, and no general relations to tumour syndrome, malignancy or MEN1 gene mutations were evident. This was not due to homozygous gene deletions, but the p15 promoter was hypermethylated in two insulinomas. No mutations were found in the pl5 gene. Conclusions Expression of p15, p18 and p27 was not generally related to the MEN1 gene mutational status of the investigated 18 PETs. The p15 gene was silenced by promoter hypermethylation in two tumours. Dysregulation of menin and the CDIs are important in PET tumorigenesis, and their interrelations remain to be elucidated.

  • 32.
    Lindberg, Daniel
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Åkerström, Göran
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Westin, Gunnar
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Mutational analyses of WNT7A and HDAC11 as candidate tumour suppressor genes in sporadic malignant pancreatic endocrine tumours2007Inngår i: Clinical Endocrinology, ISSN 0300-0664, E-ISSN 1365-2265, Vol. 66, nr 1, s. 110-114Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Objective We and others have reported loss of heterozygosity (LOH) on chromosome 3p25 in sporadic malignant pancreatic endocrine tumours (PETs). A common region of deletion on chromosome 3p25 contains numerous genes, including VHL and PPARγ, that have been excluded previously as candidate tumour suppressor genes by DNA sequencing analysis. We have analysed whether WNT7A or HDAC11 was biallelically inactivated in a group of well-characterized PETs.

    Patients and design Ten PETs from eight patients were selected from a previous study, where LOH on chromosome 3p25 was found in 11 out of 22 sporadic PETs. These tumours were examined for inactivating mutations of WNT7A and HDAC11 by direct sequencing of all exons and intron–exon boundaries. Inactivation of WNT7A expression by aberrant CpG island methylation and WNT7A protein expression were evaluated by methylation-specific polymerase chain reaction (PCR) and immunohistochemistry, respectively. HDAC11 protein expression was also examined.

    Results No point mutations, deletion or insertions were detected in either WNT7A or HDAC11 in any of the PETs. Two polymorphisms were identified in the third exon of the WNT7A gene. CpG methylation of the WNT7A gene was not detected and the WNT7A and HDAC11 proteins were normally expressed.

    Conclusion The absence of tumour-specific somatic events in WNT7A and HDAC11 suggests that these genes are unlikely to have a classical tumour suppressor gene role in sporadic malignant PETs. The putative 3p25 tumour suppressor remains to be identified.

  • 33.
    Lindberg, Daniel
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Åkerström, Göran
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Westin, Gunnar
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Mutational analysis of p27 (CDKN1B) and p18 (CDKN2C) in sporadic pancreatic endocrine tumors argues against tumor-suppressor function2007Inngår i: Neoplasia, ISSN 1522-8002, E-ISSN 1476-5586, Vol. 9, nr 7, s. 533-535Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Pancreatic endocrine tumors (PETs) arise sporadically or are associated with multiple endocrine neoplasia type 1 (MEN1) syndrome or von Hippel-Lindau syndrome. About 90% of patients with familial MEN1 display detectable MEN1 gene (menin) mutations. The cyclin-dependent kinase inhibitor p27 (CDKN1B) is a downstream target of menin and has been recently shown to be responsible for the multiple endocrine neoplasia-like syndrome in rats, where affected animals develop multiple tumors and hyperplasia in endocrine tissues, including the pancreatic islets of Langerhans. A germline nonsense truncation mutation of p27 has been recently described in a suspected MEN1 family without MEN1 mutation, raising the possibility that p27 mutation could be responsible for MEN1 phenotype. Somatic MEN1 mutations occur at low frequency in sporadic PETs; here, we subjected p27 to mutational analysis in 27 sporadic PETs. As an additional menin target, analysis of the p18 (CDKN2C) gene was included. In the p27 gene, one common polymorphism (V109G) and one novel polymorphism (g/a) in the noncoding part of exon 2 were identified. Three known polymorphisms were found in the p18 gene. These data suggest that p27 and p18 are unlikely to present classic tumor-suppressor genes in sporadic PETs.

  • 34.
    Marin, Riccardo
    et al.
    Univ Ottawa, Dept Chem & Biomol Sci, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada.
    Oussta, Fadi
    Univ Ottawa, Dept Chem & Biomol Sci, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada.
    Katea, Sarmad Naim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Prabhudev, Sagar
    McMaster Univ, Dept Mat Sci & Engn, 1280 Main St West, Hamilton, ON L8S 4M1, Canada;McMaster Univ, Canadian Ctr Electron Microscopy, 1280 Main St West, Hamilton, ON L8S 4M1, Canada.
    Botton, Gianluigi A.
    McMaster Univ, Dept Mat Sci & Engn, 1280 Main St West, Hamilton, ON L8S 4M1, Canada;McMaster Univ, Canadian Ctr Electron Microscopy, 1280 Main St West, Hamilton, ON L8S 4M1, Canada.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Hemmer, Eva
    Univ Ottawa, Dept Chem & Biomol Sci, 10 Marie Curie, Ottawa, ON K1N 6N5, Canada.
    Europium-doped ZnO nanosponges: controlling optical properties and photocatalytic activity2019Inngår i: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 7, nr 13, s. 3909-3919Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The optical features and photocatalytic activity of porous undoped and Eu3+-doped zinc oxide (ZnO) sponge-like structures, annealed at various temperatures, were assessed to establish the relationship between structure, morphology and photophysical properties. Upon monitoring the degradation of organic dye rhodamine B, undoped ZnO nanosponges annealed at 800 °C showed the highest photocatalytic activity, being among the best performing ZnO-based photocatalysts reported so far. The observed red- and blue-shift of the characteristic broad-band ZnO emission spectra as a function of the annealing temperature was ascribed to the nature of defects induced into the ZnO structure related to deficiency or excess of oxygen at lower (200 to 400 °C) and higher (500 to 1000 °C) annealing temperatures. These temperature-induced defects - along with the morphological sample characteristics - governed the photocatalytic performance. Doping-induced enhancement of the photocatalytic activity was noticed in specific samples and was found to markedly depend on the intrinsic properties of the undoped material. Overall, annealing temperature and europium doping concentration synergistically contributed to the defect structure, morphology and crystallinity, ultimately determining optical properties and therewith correlated photocatalytic activity.

  • 35. Mattsson, Andreas
    et al.
    Leideborg, Michael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Larsson, Karin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Österlund, Lars
    Adsorption and Solar Light Decomposition of Acetone on Anatase TiO2 and Niobium Doped TiO2 Thin Films2006Inngår i: Journal of Physical Chemistry B, Vol. 110, nr 3, s. 1210-1220Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Adsorption and solar light decomposition of acetone was studied on nanostructured anatase TiO2 and Nb-doped TiO2 films made by sol-gel methods (10 and 20 mol % NbO2.5). A detailed characterization of the film materials show that films contain only nanoparticles with the anatase modification with pentavalent Nb oxide dissolved into the anatase structure, which is interpreted as formation of substituted Nb=O clusters in the anatase lattice. The Nb-doped films displayed a slight yellow color and an enhanced the visible light absorption with a red-shift of the optical absorption edge from 394 nm for the pure TiO2 film to 411 nm for 20 mol % NbO2.5. In-situ Fourier transform infrared (FTIR) transmission spectroscopy shows that acetone adsorbs associatively with 1-coordination to the surface cations on all films. On Nb-doped TiO2 films, the carbonyl bonding to the surface is stabilized, which is evidenced by a lowering of the (C=O) frequency by about 20 cm-1 to 1672 cm-1. Upon solar light illumination acetone is readily decomposed on TiO2, and stable surface coordinated intermediates are formed. The decomposition rate is an order of magnitude smaller on the Nb-doped films despite an enhanced visible light absorption in these materials. The quantum yield is determined to be 0.053, 0.004 and 0.002 for the pure, 10% Nb:TiO2, and 20%Nb:TiO2, respectively. Using an interplay between FTIR and DFT calculations we show that the key surface intermediates are bidentate bridged formate and carbonate, and H-bonded bicarbonate, respectively, whose concentration on the surface can be correlated with their heats of formation and bond strength to coordinatively unsaturated surface Ti and Nb atoms at the surface. The oxidation rate of these intermediates is substantially slower than the initial acetone decomposition rate, and limits the total oxidation rate at t>7 min on TiO2, while no decrease of the rate is observed on the Nb-doped films. The rate of degradation of key surface intermediates is different on pure TiO2 and Nb-doped TiO2, but cannot explain the overall lower total oxidation rate for the Nb-doped films. Instead the inferior photocatalytic activity in Nb-doped TiO2 is attributed to an enhanced electron-hole pair recombination rate due to Nb=O cluster and cation vacancy formation.

  • 36. Moustiakimov, M
    et al.
    Kritikos, M
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Nd[Ak(OrI)4]3, a Novel tetranuclear alkoxide forming merohedrally twinned crystals2001Inngår i: Acta Cryst., Vol. C37, s. 515-516Artikkel i tidsskrift (Fagfellevurdert)
  • 37. Moustiakimov, Marat
    et al.
    Kritikos, Mikael
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    First Example of Low-Valence Ion Substitution in Ln5O(OPri)13: Mixed-Valence Europium Oxoalkoxide [EuIII4EuIIO(OPri)12(HOPri)]*HOPri2005Inngår i: Inorganic Chemistry, Vol. 44, nr 5, s. 1499-1504Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The novel mixed-valence alkoxide [Eu3+4Eu2+O(OPri)12(HOPri)]*HOPri (1) has been prepared and structurally and spectroscopically characterized. The three synthesis routes (i) metathesis of 4EuCl3, EuI2, and 14KOPri combined with hydrolysis with 1H2O, (ii) oxidation of 5[Eu4(OPri)10(HOPri)3]*2HOPri with 1.5O2, and (iii) reduction of Eu5O(OPri)13 with 0.8[Eu4(OPri)10(HOPri)3]*2HOPri all yielded pure 1, whereas (iv) reduction of Eu5O(OPri)13 with 0.36-0.5 mol of europium metal produced impure 1. The compound, having the average Eu oxidation number +2.8, is very sensitive toward further oxidation to Eu5O(OPri)13 and is part of a redox series of europium 2-propoxides with average oxidation states +2.5, +2.8, and +3. The square pyramidal molecular structure, containing an oxo-oxygen atom in the basal plane, is similar to that of the well-known Ln5O(OPri)13; the main difference is the substitution of an Eu3+-OPri pair for an Eu2+-HOPri pair in the basal plane. Fourier transform infrared (FT-IR) and UV-visible spectroscopy showed that the solid-state structure was retained on dissolution in hexane and toluene-HOPri. The compound was further characterized by differential scanning calorimetry and solubility studies.

  • 38.
    Mäkie, Peter
    et al.
    FOI, CBRN Defence and Security, Umeå.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi.
    Persson, Per
    Dept of Chemistry, Umeå University, Umeå.
    Österlund, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Adsorption of Trimethyl Phosphate on Maghemite, Hematite, and Goethite Nanoparticles2011Inngår i: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 115, nr 32, s. 8948-8959Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Adsorption of trimethyl phosphate (TMP) on well-characterized hematite, maghemite and goethite nanopartides was studied by in situ DRIFT spectroscopy as a model system for adsorption of organophosphorous (OP) compounds on iron minerals. The iron minerals were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), specific surface area, and pore size distribution. The minerals were found to consist of stoichimetrically and morphologically well-defined maghemite, hematite, and goethite nanoparticles. Analysis of in situ diffuse reflectance Fourier transform (DRIFT) spectroscopy shows that TMP bonds mainly to Lewis acid Fe sites through the O phosphoryl atom (-P=O-Fe) on hematite and maghemite. On goethite most TMP molecules bond to Bronstedt acid surface OH groups and form hydrogen bonded surface complexes. The vibrational mode analysis and uptake kinetics suggest two main reasons for the observed trend of reactivity toward TMP (hematite > maghemite > goethite): (i) larger number of accessible Lewis acid adsorption sites on hematite; (ii) stronger interaction between the Lewis acid Fe sites and the phosphoryl O atom on TAP for hematite and maghemite compared to goethite with concomitant formation of surface coordinated TMP and dimethyl phosphate intermediates. As a result, on the oxides a surface oxidation pathway dominates during the initial adsorption, which results in the formation of surface methoxy and formate. In contrast, on goethite a slower hydrolysis pathway is identified, which eventually yields phosphoric acid. The observed trends of the reactivity and analysis of the corresponding surface structure and particle morphology suggest an intimate relation between the surface chemistry of exposed crystal facets on the iron minerals. These results are important to understand OP surface chemistry on iron minerals.

  • 39.
    Pohl, Annika
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Jansson, K
    Ekstrand, Åsa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Solution Route to Metal-Alumina nano composites2005Inngår i: 13:th International Workshop on Gels and Glasses, Los Angeles, 2005, 2005, s. 2-Konferansepaper (Fagfellevurdert)
  • 40.
    Pohl, Annika
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, GunnarUppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Alkoxide Based Sol-Gel Processing of CMR Manganites2005Konferanseproceedings (Fagfellevurdert)
  • 41.
    Pohl, Annika
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för kärn- och partikelfysik. Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Alkoxide Based Sol-Gel Processing of CMR Manganites2005Inngår i: Materials Research Society Vol. 848: Solid-State Chemistry of Inorganic Materials V, 2005Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We have prepared a soluble manganese alkoxide, and used in the first all-alkoxide synthesis of Ca, Sr, and Ba substituted lanthanum manganites. The phase development from gel to target oxide was monitored by TGA, DSC, powder-XRD, FT¨CIR spectroscopy, and TEM-EDS. Here we present the effect of dopant on the phase development. It was found that the dopants influence the temperature of complete oxide formation (¡Ý650¡ãC). The main difference in phase evolution was seen in the 300-600¡ãC range, where the formation of crystalline phases in trace quantities seemed to temporarily reduce the elemental homogeneity.

  • 42.
    Pohl, Annika
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Alkoxide Route to La0.5Sr0.5CoO3 Films and Powders2005Inngår i: Journal of the American Ceramic Society, Vol. 88, nr 8, s. 2099-2105Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An all-alkoxide route to films and nano-phase powders of the La0.5Sr0.5CoO3 perovskite is described. To our knowledge, this is the first purely alkoxide-based route to (La1xSrx)CoO3, and it yields phase-pure and elementally homogeneous perovskite at 700°C by heating at 2°C/min. At 700°C, a cubic unit cell was obtained with ac=3.853Å, and after further heating to 1000°C, a rhombohedral cell could be indexed: ar=5.417 Å, r=59.94°. Ninety to 130 nm thick films of La0.5Sr0.5CoO3 were obtained by spin coating. The gel-to-oxide conversion was studied in some detail, using thermo-gravimetric analysis, differential scanning calorimetry, powder X-ray diffraction, IR spectroscopy, and transmission electron microscope equipped with an energy-dispersive X-ray spectrometer.

  • 43.
    Pohl, Annika
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Preparation of La1-x(Sr,Ba)xMnO3 Nano-Phase Powders and Films from Alkoxide Precursors2002Inngår i: 10th International Ceramics Congress 2002 Proceedings, 2002, s. 453-Konferansepaper (Fagfellevurdert)
  • 44.
    Pohl, Annika
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Jansson, K
    Preparation of La0.67Ca0.33MnO3 Nanophase Powders and Films from Alkoxide Precursors2002Inngår i: Chem. Mater., Vol. 14, nr 5, s. 1981-1988Artikkel i tidsskrift (Fagfellevurdert)
  • 45.
    Pohl, Annika
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Jansson, Kazuhiko
    Preparation of La0.75Sr0.25MnO3 Nano-Phase Powders and Films from Alkoxide Precursors2003Inngår i: Journal of Sol-Gel Science and Technology, Vol. 26, s. 257-260Artikkel i tidsskrift (Fagfellevurdert)
  • 46.
    Pohl, Annika
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Kritikos, M
    Preparation, structure, and properties of a new giant manganese oxo-alkoxide wheel, [Mn19O12(OC2H4OCH3)(14)(HOC2H4OCH3)(10)]center dot HOC2H4OCH32001Inngår i: CHEMISTRY-A EUROPEAN JOURNAL, ISSN 0947-6539, Vol. 7, nr 16, s. 3438-3445Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Alkoxides are of great interest as precursors for sol-gel processing of advanced ceramic materials, but there is very little general knowledge about the low-valent 3d-element alkoxides. The novel oxo-alkoxide, [Mn19O12(moe)(14)- (moeH)(10)] . MOEH (MOE =

  • 47.
    Pohl, Annika
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Lashgari, K
    Ottosson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    La0.5Sr0.5CoO3 electrode films by alkoxide based sol-gel synthesis2005Inngår i: 13:th International Workshop on Gels and Glasses, Los Angeles, 2005, 2005, s. 2-Konferansepaper (Fagfellevurdert)
  • 48.
    Pohl, Annika
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Ottosson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi, Oorganisk kemi. oorganisk kemi.
    Porous and dense perovskite films2007Inngår i: Nanostructured Materials and Nanotechnology, Vol 28, 2007, s. 153-163Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Lao.5Sro.5Co03 (LSCO) and La0.67Ca0.33MnO3 (LCMO) films were prepared by sol-gel techniques and their structural and transport properties investigated. Films were spin-coated onto (001) LaAlO3 (LAO), (001) SrTiO3 (STO), Pt/TiO2/SiO2/Si, and Al2O3 substrates, and ictural properties were investigated using X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM). SEM studies showed that the films were crack-free and adhered well to the substrates. No preferential orientation of the pervoskite films was observed on Si- or Pt/TiCVSiCVSi-substrates, but films deposited on LAO and STO showed good alignment with the substrate. Transport measurements of epitaxial LCMO films show maximum temperature coefficient of resisth (TCR) of 6.1 % K1 aät 241 K and colossal magnetoresistance (CMR) of 32 % a at 246 K. The conductivity of around l .9 mQcm.

  • 49.
    Rautiainen, Sari
    et al.
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Di Francesco, Davide
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Katea, Sarmad Naim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Oorganisk kemi.
    Tungasmita, Duangamol N.
    Chulalongkorn Univ, Fac Sci, Dept Chem, Ctr Excellence Catalysis Bioenergy & Renewable Ch, Bangkok 10330, Thailand.
    Samec, Joseph S. M.
    Stockholm Univ, Dept Organ Chem, SE-10691 Stockholm, Sweden.
    Lignin Valorization by Cobalt-Catalyzed Fractionation of Lignocellulose to Yield Monophenolic Compounds2019Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 12, nr 2, s. 404-408Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herein, a catalytic reductive fractionation of lignocellulose is presented using a heterogeneous cobalt catalyst and formic acid or formate as a hydrogen donor. The catalytic reductive fractionation of untreated birch wood yields monophenolic compounds in up to 34 wt % yield of total lignin, which corresponds to 76% of the theoretical maximum yield. Model compound studies revealed that the main role of the cobalt catalyst is to stabilize the reactive intermediates formed during the organosolv pulping by transfer hydrogenation and hydrogenolysis reactions. Additionally, the cobalt catalyst is responsible for depolymerization reactions of lignin fragments through transfer hydrogenolysis reactions, which target the beta-O-4' bond. The catalyst could be recycled three times with only negligible decrease in efficiency, showing the robustness of the system.

  • 50.
    Sanyal, Biplab
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Grånäs, Oscar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Knut, Ronny
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Coleman, V. A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Thunström, Patrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Iusan, Diana M
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Karis, Olof
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Eriksson, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och materialvetenskap, Materialteori.
    Westin, Gunnar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för materialkemi.
    Electronic structure of Co doped ZnO: Theory and experiment2008Inngår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 103, nr 7, s. 07D130-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have studied the electronic structure of Co doped ZnO by theory and experiment. Photoelectron and x-ray absorption spectroscopy experiments were performed on 5% Co doped ZnO thin films. The results show that Co-3d states lie in the valence band and hybridize considerably with O-2p states. These results compare qualitatively with our density functional calculations combined with a Hubbard approach to include strong electron correlations within the Co-3d state.

12 1 - 50 of 65
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