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  • 1.
    Ahrén, Maria
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Olsson, Petter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Söderlind, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Klasson, Anna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Radiology . Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Petoral, Rodrigo Jr
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Rare earth nanoparticles as contrast agent in MRI: Nanomaterial design and biofunctionalization2007In: IVC-17/ICSS-13 ICNT,2007, 2007Conference paper (Other academic)
  • 2.
    Ahrén, Maria
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Selegård, Linnéa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Klasson, Anna
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Abrikossova, Natalia
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Skoglund, Caroline
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, The Institute of Technology.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Synthesis and Characterization of PEGylated Gd2O3 Nanoparticles for MRI Contrast Enhancement2010In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, no 8, p. 5753-5762Article in journal (Refereed)
    Abstract [en]

    Recently, much attention has been given to the development of biofunctionalized nanoparticles with magnetic properties for novel biomedical imaging. Guided, smart, targeting nanoparticulate magnetic resonance imaging (MRI) contrast agents inducing high MRI signal will be valuable tools for future tissue specific imaging and investigation of molecular and cellular events. In this study, we report a new design of functionalized ultrasmall rare earth based nanoparticles to be used as a positive contrast agent in MRI. The relaxivity is compared to commercially available Gd based chelates. The synthesis, PEGylation, and dialysis of small (3−5 nm) gadolinium oxide (DEG-Gd2O3) nanoparticles are presented. The chemical and physical properties of the nanomaterial were investigated with Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and dynamic light scattering. Neutrophil activation after exposure to this nanomaterial was studied by means of fluorescence microscopy. The proton relaxation times as a function of dialysis time and functionalization were measured at 1.5 T. A capping procedure introducing stabilizing properties was designed and verified, and the dialysis effects were evaluated. A higher proton relaxivity was obtained for as-synthesized diethylene glycol (DEG)-Gd2O3 nanoparticles compared to commercial Gd-DTPA. A slight decrease of the relaxivity for as-synthesized DEG-Gd2O3 nanoparticles as a function of dialysis time was observed. The results for functionalized nanoparticles showed a considerable relaxivity increase for particles dialyzed extensively with r1 and r2 values approximately 4 times the corresponding values for Gd-DTPA. The microscopy study showed that PEGylated nanoparticles do not activate neutrophils in contrast to uncapped Gd2O3. Finally, the nanoparticles are equipped with Rhodamine to show that our PEGylated nanoparticles are available for further coupling chemistry, and thus prepared for targeting purposes. The long term goal is to design a powerful, directed contrast agent for MRI examinations with specific targeting possibilities and with properties inducing local contrast, that is, an extremely high MR signal at the cellular and molecular level.

  • 3.
    Ahrén, Maria
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Selegård, Linnéa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Linares, Mathieu
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    Kauczor, Joanna
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    Norman, Patrick
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    A simple polyol-free synthesis route to Gd2O3 nanoparticles for MRI applications: an experimental and theoretical study2012In: Journal of nanoparticle research, ISSN 1388-0764, E-ISSN 1572-896X, Vol. 14, no 8Article in journal (Refereed)
    Abstract [en]

    Chelated gadolinium ions, e. g., GdDTPA, are today used clinically as contrast agents for magnetic resonance imaging (MRI). An attractive alternative contrast agent is composed of gadolinium oxide nanoparticles as they have shown to provide enhanced contrast and, in principle, more straightforward molecular capping possibilities. In this study, we report a new, simple, and polyol-free way of synthesizing 4-5-nm-sized Gd2O3 nanoparticles at room temperature, with high stability and water solubility. The nanoparticles induce high-proton relaxivity compared to Gd-DTPA showing r(1) and r(2) values almost as high as those for free Gd3+ ions in water. The Gd2O3 nanoparticles are capped with acetate and carbonate groups, as shown with infrared spectroscopy, near-edge X-ray absorption spectroscopy, X-ray photoelectron spectroscopy and combined thermogravimetric and mass spectroscopy analysis. Interpretation of infrared spectroscopy data is corroborated by extensive quantum chemical calculations. This nanomaterial is easily prepared and has promising properties to function as a core in a future contrast agent for MRI.

  • 4.
    Ballem, Mohamed Ali
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Nordblad, Per
    Uppsala Unversity, Sweden.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Growth of Gd2O3 nanoparticles inside mesoporous silica frameworks2013In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 168, p. 221-224Article in journal (Refereed)
    Abstract [en]

    Gadolinium oxide (Gd2O3) nanoparticles with very small size, and narrow size distribution were synthesized by infiltration of Gd(NO3)3.6H2O as an oxide precursor into the pores of SBA-15 mesoporous silica using a wet-impregnation technique. High resolution transmission electron microscopy and X-ray diffraction show that during the hydrothermal treatment of the precursor at 550 °C, gadolinium oxide nanoparticles inside the silica pores are formed. Subsequent dissolution of the silica template by NaOH resulted in well dispersed nanoparticles with an average diameter of 3.6 ± 0.9 nm.

  • 5.
    Becker, Richard
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Inorganic Chemistry . Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Inorganic Chemistry . Linköping University, The Institute of Technology.
    CTAB promoted synthesis of Au nanorods - Temperature effects and stability consideration2010In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 343, no 1, p. 25-30Article in journal (Refereed)
    Abstract [en]

    A systematic study is performed of the influence of surfactant and temperature on the aspect ratio and monodispersity of Au nanorods, synthesized by a seed-mediated growth technique in water using cetyltrimethylammonium bromide (CTAB) as surfactant. The changes in aspect ratio with temperature show an "anomalous" behaviour, where the aspect ratio first decreases with increasing temperature, reaching a minimum at about 55oC, and after that increases again reaching a maximum at about 80oC. A physical explanation of the observed behaviour is proposed. It has also been studied how the CTAB concentration in the cleansing water used in the post-synthesis treatment of the samples affected the stability of the gold suspension. It was found that without the presence of a surfactant such as CTAB in the washing medium, only very few centrifugations can be carried out without considerable loss of product. Characterization of prepared samples was performed with UV-Vis and TEM.

  • 6.
    Becker, Richard
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Synthesis of silver nanowires in aqueous solutions2010In: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 64, no 8, p. 956-958Article in journal (Refereed)
    Abstract [en]

    Silver nanowires with a diameter of 30 nm and typical lengths of 5–10 μm have been synthesized in an aqueous medium. To initiate the reaction, citrate ions were used, and during the reaction the aromatic organicmolecules polymerize forming “straight” chain surfactants which support the formation of nanowires. Characterization by TEM and HRETM revealed the nanowires to be highly crystalline with a growth along the [110] direction.

  • 7. Bolyos, Elinor
    et al.
    Lawrence, David
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Dahlgren, Maria
    Treatment of process water through non-chemical methods: Removal of heavy metals and organic material2001Report (Other (popular science, discussion, etc.))
    Abstract [en]

    Linköping University, in collaboration with Ribea AB, has been studying the removal of heavy metals and organic matter from process water. Specifically, the product water from a metal-polishing company in Gamleby had Zn, Cu and particulate levels that were in excess of allowable limits. The objective of the work was to develop a process for removal of these metals and the particulates without the use of chemicals and to design and install an on-site facility for larger-scale tests. Additionally, a further goal was to generalise the findings such that metals and organic matter could be removed from other process waters.

  • 8.
    Buchholt, Kristina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Ieva, E.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Ojamäe, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Torsi, L
    Universita degli Studi di Bari, Italy.
    Lutic, D.
    Växjö universitet.
    Strand, M
    Växjö universitet.
    Sanati, M.
    Växjö universitet.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    FET devices with gold nanoparticle gate material as nitrogen oxide gas sensors2006In: Proceedings from E-MRS 2006, Nice France, May 29- June 1, 2006, 2006, p. 87-92Conference paper (Refereed)
    Abstract [en]

       

  • 9.
    Buchholt, Kristina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Ieva, Eliana
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Torsi, L
    Dipartimento di Chimica, Universita degli Studi di Bari, Italy.
    Cioffi, N
    Dipartimento di Chimica, Universita degli Studi di Bari, Italy.
    Colaianni, L
    Dipartimento di Chimica, Universita degli Studi di Bari, Italy.
    Söderlind, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    A comparison between the use of Pd- and Au-nanoparticles as sensing layers in a field effect NOx-sensitive sensor2007In: The 2nd Conference on Sensing Technology ICST,2007, 2007, p. 87-92Conference paper (Refereed)
  • 10.
    Buchholt, Kristina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Leva, E
    Dipartimento di Chimica, Università degli Studi di Bari, Bari, Italy.
    Torsi, L
    Dipartimento di Chimica, Università degli Studi di Bari, Bari, Italy.
    Cioffi, N
    Dipartimento di Chimica, Università degli Studi di Bari, Bari, Italy.
    Colaianni, L
    Dipartimento di Chimica, Università degli Studi di Bari, Bari, Italy.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Electrochemically Synthesised Pd- and Au-nanoparticles as sensing layers in NOx-sensitive field effect devices2008In: Smart Sensors and Sensing Technology / [ed] Subhas Chandra Mukhopadhyay and Gourab Sen Gupta, Berlin, Heidelberg: Springer , 2008, p. 63-75Conference paper (Other academic)
    Abstract [en]

    An environmental pollutant of great concern is NOx (nitrogen monoxide and nitrogen dioxide). Here we report the utilisation of electrochemically synthesised gold and palladium nanoparticles as catalytically active gate material on gas sensitive field effect sensor devices. The synthesised nanoparticles have been characterised by TEM and XPS, and the morphology of the thermally treated nanostructured sensing layers has been investigated using SEM and XPS. Measurements on the gas response of the palladium as well as the gold nanoparticle sensors towards a number of analytes found in automotive gas exhausts were performed and their response patterns were compared. The initial gas response measurements show interesting sensing properties for both the gold and the palladium nanoparticle sensors towards NOx detection.

  • 11.
    Darmastuti, Zhafira
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Bhattacharyya, P.
    Dept. of Electronics and Telecommunication Engineering, Bengal Engineering and Science University, India.
    Andersson, Mike
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Kanungo, Jayita
    IC Design & Fabrication Centre, Dept. of Electronics & Telecommunications Engineering, Jadavpur University, Kolkata, India.
    Basu, Sukumar
    IC Design & Fabrication Centre, Dept. of Electronics & Telecommunications Engineering, Jadavpur University, Kolkata, India.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Inorganic Chemistry.
    Ojamäe, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Chemistry.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    SiC-FET methanol sensors for process control and leakage detection2013In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 187, no SI, p. 553-562Article in journal (Refereed)
    Abstract [en]

    Two types of SiC based field effect transistor sensors, with Pt or Ir gate, were tested to detect methanol in the concentration range of 0–1600 ppm for both process control and leak detection applications. The methanol response was investigated both with and without oxygen, since the process control might be considered as oxygen free application, while the sensor is operated in air during leak detection. Pt sensors offered very fast response with appreciably high response magnitude at 200 °C, while Ir sensors showed both higher response and response time up to 300 °C, but this decreased considerably at 350 °C. Cross sensitivity effect in presence of oxygen, hydrogen, propene and water vapor was also investigated. The presence of oxygen improved the response of both sensors, which is favorable for the leak detection application. Hydrogen had a large influence on the methanol response of both sensors, propene had a negligible influence, while water vapor changed direction of the methanol response for the Pt sensor. The detection mechanism and different sensing behavior of Pt and Ir gate sensors were discussed in the light of model reaction mechanisms derived from hybrid density-functional theory quantum-chemical calculations.

  • 12.
    Darmastuti, Zhafira
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Bhattacharyya, Partha
    Bengal Engineering and Science University, India.
    Basu, Sukumar
    Jadavpur University, India.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Ojamäe, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    SiC - FET Sensors for methanol leakage detection2012In: Proceeding of the 14th International Meeting on Chemical Sensors (IMCS 2012), 2012, p. 1579-1582Conference paper (Other academic)
    Abstract [en]

    Pt and Ir SiC based Field Effect Transistor sensors were tested to detect low concentration of methanol (<200 ppm) for both process control and leak detection applications. Pt sensors gave good and very fast response at 200°C, while Ir sensors gave larger but much slower response. The presence of oxygen improved the response of the sensor which was favorable for the leak detection application. The influence of hydrogen and propene to the sensor response was also studied. Beside the experimental work, the detection mechanism and different sensing behavior of Pt and Ir were studied by quantum chemical calculations.

  • 13.
    Ekström, Thommy
    et al.
    AB Sandvik Hard Materials, Stockholm.
    Käll, Per-Olov
    University of Stockholm.
    Nygren, Mats
    University of Stockholm.
    Olsson, Per-Olof
    University of Stockholm.
    Dense single-phase β-sialon ceramics by glass-encapsulated hot isostatic pressing1989In: Journal of Materials Science, ISSN 0022-2461, Vol. 24, no 5, p. 1853-1861Article in journal (Refereed)
    Abstract [en]

    Single phase-sialon ceramics, Si6–z Al z O z N8–z , have been prepared from carefully balanced powder mixtures, also taking account of any excess oxygen in the starting materials. Sintering powder compacts in a nitrogen atmosphere (0.1 MPa) at 1800° C or higher transforms the starting mixture into a-sialon solid solution atz-values up to about 4.3, but the sintered material has an open porosity. Addition of 1 wt% Y2O3 to the starting mix improved the sintering behaviour somewhat and the density of the sintered compacts reached 95% of the theoretical value. By glass-encapsulated hot isostatic pressing at 1825° C, however, sintered materials of virtually theoretical density could be obtained, with or without the 1 wt% Y2O3 addition. These latter samples have been studied by X-ray diffraction and electron microscopy, and their hardness and indentation fracture toughness have been measured. It was found that the maximum extension of the-sialon phase composition at 1825° C and 200 MPa pressure is slightly below 4,z 3.85 and about 4.1 at atmospheric pressure, and that the hexagonal unit cell parameters are linear functions of thez-value. The single-phase-sialon ceramics had no residual glassy grain-boundary phase. The grain shape was equi-axed and the grain size increased from about 1m at lowz-values to 5m at highz-values. At lowz-values the hardness at a 98 N load was 1700 and the fracture toughness 3, whereas an increase inz above 1 caused both the hardness and fracture toughness to decrease significantly. Addition of 1 wt % Y2O3 to the starting mix prior to the HIP-sintering gave rise to a small amount of amorphous intergranular phase, changes in grain size and shape, a clear increase in fracture toughness and a moderate decrease in hardness.

  • 14.
    Ekström, Thommy
    et al.
    AB Sandvik Hard Materials, Stockholm, Sweden.
    Käll, Per-Olov
    University of Stockholm, Sweden.
    Nygren, Mats
    University of Stockholm, Sweden.
    Olsson, Per-Olof
    University of Stockholm, Sweden.
    Mixed α- and β-(Si-Al-O-N) Materials with Yttria and Neodymia Additions1988In: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 105/106, p. 161-168Article in journal (Refereed)
    Abstract [en]

    A number of ceramic materials have been fabricated on a semipilot plant scale at different overall compositions in the (Y, Nd)---Al---O---N system at 177°C. Constant molar amounts of oxide mixtures of Y2O3: Nd2O3 in the ratios 100:0, 75:25, 50:50, 25:75 or 0:100 have been added. Dense materials were obtained for all compositions except those corresponding to mixed α- and β-(Si---Al---O---N) with higher α-(Si---Al---O---N) contents and high Nd2O3 contents. At the preparation temperature used in this study, the formation of an α-(Nd---Si---Al---O---N) seems prohibited and, thus, with increasing Nd2O3 content the amount of α-(Si---Al---O---N) decreased. The Nd2O3 added mainly formed crystalline intergranular phases such as the N-melilite phase, which increased in amount with increasing Nd2O3 in the starting mix. Hardness and indentation fracture toughness measurements were made and are discussed in relation to the phase composition and the microstructure. Some of the high Nd2O3 content Si---Al---O---N materials have as high fracture toughness values as the pure Y2O3 Si---Al---O---N materials do.

  • 15.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Klasson, Anna
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Vahlberg, Cecillia
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    High Proton Relaxivity for Gadolinium Oxide Nanoparticles2006In: Magnetic Resonance Materials in Physics, Biology and Medicine, ISSN 0968-5243, E-ISSN 1352-8661, Vol. 19, no 4, p. 180-186Article in journal (Refereed)
    Abstract [en]

    Objective: Nanosized materials of gadolinium oxide can provide high-contrast enhancement in magnetic resonance imaging (MRI). The objective of the present study was to investigate proton relaxation enhancement by ultrasmall (5 to 10 nm) Gd2O3 nanocrystals.

    Materials and methods: Gd2O3 nanocrystals were synthesized by a colloidal method and capped with diethylene glycol (DEG). The oxidation state of Gd2O3 was confirmed by X-ray photoelectron spectroscopy. Proton relaxation times were measured with a 1.5-T MRI scanner. The measurements were performed in aqueous solutions and cell culture medium (RPMI).

    Results: Results showed a considerable relaxivity increase for the Gd2O3–DEG particles compared to Gd-DTPA. Both T 1 and T 2 relaxivities in the presence of Gd2O3–DEG particles were approximately twice the corresponding values for Gd–DTPA in aqueous solution and even larger in RPMI. Higher signal intensity at low concentrations was predicted for the nanoparticle solutions, using experimental data to simulate a T1-weighted spin echo sequence.

    Conclusion: The study indicates the possibility of obtaining at least doubled relaxivity compared to Gd–DTPA using Gd2O3–DEG nanocrystals as contrast agent. The high T 1 relaxation rate at low concentrations of Gd2O3 nanoparticles is very promising for future studies of contrast agents based on gadolinium-containing nanocrystals.

  • 16.
    Eriksson, Jens
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lloyd-Spets, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    ZnO nanoparticles or ZnO films: A comparison of the gas sensing capabilities2009In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 137, no 1, p. 94-102Article in journal (Refereed)
    Abstract [en]

    Zinc oxide is an interesting material for bio and chemical sensors. it is a semiconducting metal oxide with potential as an integrated multisensing sensor platform, which simultaneously detects Parameters like change in field effect, mass and Surface resistivity. in this investigation we have used resistive sensor measurements regarding the oxygen gas sensitivity in order to characterize sensing layers based on electrochemically produced ZnO nanoparticles and PE-MOCVD grown ZnO films. Proper annealing procedures were developed in order to get stable sensing properties and the oxygen sensitivity towards operation temperature was investigated. The ZnO nanoparticles showed a considerably increased response to oxygen as compared to the films. Preliminary investigations were also performed regarding the selectivity to other gases present in car exhausts or flue gases.

  • 17.
    Fortin, Marc-Andre
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Petoral, Rodrigo Jr
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Söderlind, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Synthesis of gadolinium oxide nanoparticles as a contrast agent in MRI2006In: Trends in Nanotechnology,2006, 2006Conference paper (Other academic)
    Abstract [en]

           

  • 18.
    Fortin, Marc-André
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Petoral Jr, Rodrigo M.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, Faculty of Science & Engineering.
    Klasson, Anna
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Veres, Teodor
    National Research Council of Canada (CNRC-IMI) 75, Boucherville, QC, Canada.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Polyethylene glycol-cover ultra-small Gd2O3 nanoparticles for positive contras at 1.5 T magnetic resonance clinical scanning2007In: Nanotechnology, ISSN 0957-4484, Vol. 18, no 39, p. 395501-Article in journal (Refereed)
    Abstract [en]

    The size distribution and magnetic properties of ultra-small gadolinium oxide crystals (US-Gd2O3) were studied, and the impact of polyethylene glycol capping on the relaxivity constants (r1, r2) and signal intensity with this contrast agent was investigated. Size distribution and magnetic properties of US-Gd2O3 nanocrystals were measured with a TEM and PPMS magnetometer. For relaxation studies, diethylene glycol (DEG)-capped US-Gd2O3 nanocrystals were reacted with PEG-silane (MW 5000). Suspensions were adequately dialyzed in water to eliminate traces of Gd3+ and surfactants. The particle hydrodynamic radius was measured with dynamic light scattering (DLS) and the proton relaxation times were measured with a 1.5 T MRI scanner. Parallel studies were performed with DEG–Gd2O3 and PEG-silane–SPGO (Gd2O3,< 40 nm diameter). The small and narrow size distribution of US-Gd2O3 was confirmed with TEM (~3 nm) and DLS. PEG-silane–US-Gd2O3 relaxation parameters were twice as high as for Gd–DTPA and the r2/r1 ratio was 1.4. PEG-silane–SPGO gave low r1 relaxivities and high r2/r1 ratios, less compatible with positive contrast agent requirements. Higher r1 were obtained with PEG-silane in comparison to DEG–Gd2O3. Treatment of DEG–US-Gd2O3 with PEG-silane provides enhanced relaxivity while preventing aggregation of the oxide cores. This study confirms that PEG-covered Gd2O3 nanoparticles can be used for positively contrasted MR applications requiring stability, biocompatible coatings and nanocrystal functionalization.

  • 19.
    Grins, Jekabs
    et al.
    Stockholms universitet.
    Käll, Per-Olov
    Stockholms universitet.
    Svensson, Gunnar
    Stockholms universitet.
    Phases in the ZrxTa1-x(O,N)y System, Formed by Ammonolyses of Zr-Ta Gels. Preparation of Baddeleyite Type Solid Solution Phase ZrxTa1-xO1+xN1-x, 0≤x≤11994In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 4, p. 1293-1301Article in journal (Refereed)
    Abstract [en]

      Phase formation in the system ZrxTa1x(O,N)y has been studied by ammonolysis of Zr-Ta gels, prepared by the sol–gel technique, at temperatures between 700 and 1000 °C. The starting gels and observed phases were characterised by X-ray powder diffraction (XRPD), scanning and transmission electron microscopy (SEM and TEM) and thermogravimetric (TG) analysis. Oxynitride phases of compositions ZrxTa1–xO1 +xN1–x, 0≤x≤1, with the baddeleyite-type structure, were prepared at 800 °C. The unit-cell volume increased linearly from 127.8 Å3 for TaON (x= 0) to 140.9 Å3 for ZrO2(x= 1). The structure was verified for the composition Zr0.4Ta0.6O1.6N0.4(x= 0.4) by a Rietveld refinement (RF= 3.5%) using Cu-Kα1, XRPD data. An orthorhombic oxynitride phase was observed in preparations at 700 °C for 0.26 ≤x≤ 0.90 in ZrxTa1–xO1+xN1–x. Unit-cell parameters and powder X-ray reflection intensities agree with an orthorhombic ZrO2 type structure. According to X-ray data, a cubic solid solution phase with a fluorite related subcell is present in materials prepared at 900 °C for 0.26≤x≤ 0.68. However, electron microdiffraction patterns suggest a metrically monoclinic unit cell with a = 6.1 Å, b= 14.1 Å, c= 7.1 Å and β= 125°. The Ta3N5, type of structure was found to incorporate up to ca. 18 atom% Zr at 900 and 1000 °C.

  • 20.
    Grins, Jekabs
    et al.
    Stockholm University.
    Käll, Per-Olov
    Stockholm University.
    Svensson, Gunnar
    Stockholm University.
    Synthesis and Structural Characterisation of MnWN2, Prepared by Ammonolysis of MnWO41995In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 5, no 4, p. 571-575Article in journal (Refereed)
    Abstract [en]

      A new ternary transition-metal nitride, the composition of which is close to MnWN2, has been synthesized by ammonolysis of X-ray amorphous MnWO4 at 800 °C. The Guinier-Hägg powder pattern could be indexed with a hexagonal cell with a = 2.921 3(3)Å and c =10.957(2)Å. Although no superstructure reflections could be observed in the X-ray powder diffraction pattern, such reflections were revealed by electron diffraction. In most of the crystallites investigated, the relationship between supercell and the hexagonal (sub)cell was found to be asuper=3ahex. A Rietveld structure determination, based on space group P63mc(no. 186), showed that the metal atoms were approximately close-packed in an ABAC…s sequence with Mn at site 2(a) and W at site 2(d). The lowest RF value (10%) was obtained for an ordered structure model with the Mn and N atoms occupying 2(a) and the W and N at sites 2(b). Measurements of the magnetic susceptibility, and of the electrical resistivity, indicated a metallic behaviour of MnWN2.

  • 21.
    Grins, Jekabs
    et al.
    Stockholm University.
    Käll, Per-Olov
    Stockholm University.
    Svensson, Gunnar
    Stockholm University.
    Synthesis, structure and magnetic susceptibility of the oxynitride spinell Mn2(MnTa3)N6-δO2+δ, 0≤δ≤11995In: Journal of Solid State Chemistry, ISSN 0022-4596, E-ISSN 1095-726X, Vol. 117, no 1, p. 48-54Article in journal (Refereed)
    Abstract [en]

    The oxynitride spinel Mn2(MnTa3)N6-δO2+δ, with 0 ≤ δ ≤ 1, has been synthesized at 1175 K by ammonolysis of a mixture of a Ta-containing xerogel and Mn(OAc)2 · 4H2O. The N content was determined by combustion analysis and thermogravimetric oxidation, yielding a composition confined between Mn2(MnTa3)N6O2 (δ = 0) and Mn2(MnTa3)N5O3 (δ = 1). The structure is cubic, with space group Fd3m and a = 8.8353(3) Å. It was refined using the Rietveld technique and neutron powder diffraction data collected at room temperature and 15 K, to RF = 2.9 and 3.8%, respectively. The tetrahedral sites are occupied only by Mn atoms and the octahedral sites statistically by 25% Mn and 75% Ta atoms. The N and O atoms are randomly distributed over the anion sites. The magnetic susceptibility exhibits a maximum at 29 K and a Curie-Weiss behavior at higher temperatures with θa = -250(20) K and μeff = 5.7(2) Bohr magnetons per Mn atom. The neutron powder diffraction data collected at 15 K showed no evidence of magnetic ordering. A NaCl-type phase with a = 4.4382(2) Å and tentative composition Mn0.8Ta0.2(O,N) was observed in preparations at 1175 K. A hexagonal Mn4Ta2(O,N)x phase with cell dimensions a = 5.3024(4) Å, c = 14.493(2) Å was obtained at 973 K.

  • 22.
    Gustafsson, Håkan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ahrén, Maria
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Córdoba Gallego, José M.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, Faculty of Science & Engineering.
    Nordblad, Per
    Uppsala Universitet.
    Westlund, Per-Olof
    Umeå Universitet.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Magnetic and Electron Spin Relaxation Properties of (GdxY1-x)2O3 (0 ≤ x ≤ 1) Nanoparticles Synthesized by the Combustion Method. Increased Electron Spin Relaxation Times with Increasing Yttrium Content2011In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 115, no 13, p. 5469-5477Article in journal (Refereed)
    Abstract [en]

    The performance of a magnetic resonance imaging contrast agent (CA) depends on several factors, including the relaxation times of the unpaired electrons in the CA. The electron spin relaxation time may be a key factor for the performance of new CAs, such as nanosized Gd2O3 particles. The aim of this work is, therefore, to study changes in the magnetic susceptibility and the electron spin relaxation time of paramagnetic Gd2O3 nanoparticles diluted with increasing amounts of diamagnetic Y2O3. Nanoparticles of (GdxY1-x)2O3 (0 e x e 1) were prepared by the combustion method and thoroughly characterized (by X-ray di.raction, transmission electron microscopy, thermogravimetry coupled with mass spectroscopy, photoelectron spectroscopy, Fourier transform infrared spectroscopy, and magnetic susceptibility measurements). Changes in the electron spin relaxation time were estimated by observations of the signal line width in electron paramagnetic resonance spectroscopy, and it was found that the line width was dependent on the concentration of yttrium, indicating that diamagnetic Y2O3 may increase the electron spin relaxation time of Gd2O3 nanoparticles.

  • 23.
    Ieva, Eliana
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Buchholt, Kristina
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Colaianni, L
    University of Bari.
    Cioffi, N
    University of Bari.
    Sabbatini, L
    University of Bari.
    Capitani, G C
    University of Bari.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry.
    Torsi, L
    University of Bari.
    Au Nanoparticles as Gate Material for NOx Field Effect Capacitive Sensors2008In: Sensor letters, ISSN 1546-198X, Vol. 6, no 4, p. 577-584Article in journal (Refereed)
    Abstract [en]

    Gold nanoparticles (Au-NPs) are electrochemically synthesized in the presence of tetra-alkylammonium stabilizers and used as active element in Field Effect capacitive gas sensors. Before use, the sensing area is treated by a relatively mild annealing procedure aimed to partially remove the organic stabilizer without loosing the nano-structured character of the particles. Both pristine and annealed materials have been subjected to a spectroscopic and morphological characterization (by means of UV-Vis, XPS, TEM, SEM techniques). Preliminary results on the application of AuNPs as gate material for NO, sensing are reported. The sensor is able to detect NO, with appreciable selectivity and low response towards the other tested gases (C3H6, CO, H-2, NH3).

  • 24.
    Ieva, Eliana
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Buchholt, Kristina
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Colaianni, L
    Dipartimento di Chimica, Università degli Studi di Bari, Italy .
    van der Werf, I.D.
    Dipartimento di Chimica, Università degli Studi di Bari, Italy .
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Torsi, L
    Dipartimento di Chimica, Università degli Studi di Bari, Bari, Italy .
    Gold Nanoparticle Sensors For Environmental Pollutant Monitoring2007In: Proceedings of the 2007 2nd IEEE International Workshop on Advances in Sensors and Interfaces, June 26-27, 2007 Bari, Italy, IEEE , 2007, p. 1-4Conference paper (Other academic)
    Abstract [en]

         Gold nanoparticles (Au-NPs) have been synthesised using a sacrificial anode electrolysis in the presence of tetra-alkyl-ammonium halides, employed as cationic stabilizers. Catalytic NPs have been then deposited on top of Field Effect (FE) gas sensing devices and subjected to mild annealing procedures. Transmission Electron Microscopy (TEM) shows that the NP average core diameter is around 5 nm. X-Ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM) have been applied to the surface characterization of the annealed NP films used as active sensing layers. Morphological and spectroscopic results demonstrate that the annealed inorganic nano-clusters are finely dispersed and maintain a metallic oxidation state. Au-NPs can be proficiently employed as gate material in Si-Field Effect Gas Sensors. Preliminary results show interesting selectivity and sensitivity sensing features towards NOx detection.

  • 25.
    Kanungo, Jayita
    et al.
    IC Design & Fabrication Centre, Dept. of Electronics & Telecommunications Engineering, Jadavpur University, Kolkata, India.
    Andersson, Mike
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Darmastuti, Zhafira
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Basu, Sukumar
    IC Design & Fabrication Centre, Dept. of Electronics & Telecommunications Engineering, Jadavpur University, Kolkata, India.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Ojamäe, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Development of SiC-FET methanol sensor2011In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 160, no 1, p. 72-78Article in journal (Refereed)
    Abstract [en]

    A silicon carbide based field effect transistor (SiC-FET) structure was used for methanol sensing. Due to the chemical stability and wide band gap of SiC, these sensors are suitable for applications over a wide temperature range. Two different catalytic metals, Pt and Ir, were tested as gate contacts for detection of methanol. The sensing properties of both Ir gate and Pt gate SiC-FET sensors were investigated in the concentration range 0.3–5% of methanol in air and in the temperature range 150–350 °C. It was observed that compared to the Ir gate sensor, the Pt gate sensor showed higher sensitivity, faster response and recovery to methanol vapour at comparatively lower temperature, with an optimum around 200 °C. Quantum-chemical calculations were used to investigate the MeOH adsorption and to rationalize the observed non-Langmuir behavior of the response functions. The methanol sensing mechanism of the SiC-FET is discussed.

  • 26.
    Khan, Yagoob
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Tajammul Hussain, Syed
    National Centre for Physics, Quaid-e-Azam University Campus, Islamabad, Pakistan.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    On the decoration of 3D nickel foam with single crystal ZnO nanorod arrays and their cathodoluminescence study2013In: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 90, p. 126-130Article in journal (Refereed)
    Abstract [en]

    Starting with an ammonical solution of zinc acetate, dense single crystal ZnO nanorod arrays were grown directly on high surface area porous 3D nickel foam substrates using a low temperature hydrothermal route. Heterogeneous nucleation of the nanorods with diameters around 100 nm can be conveniently and reproducibly Controlled by adjusting the amount of ammonia added to the growth solution. X-ray diffraction and HRTEM analysis confirmed the single phase wurtzite structure and c-axis orientation of the as grown ZnO nanorod arrays. Cathodoluminescence measurements indicate that the as-grown nanorod arrays were rich in atomic defects and gave strong orange emissions in the visible region. The nanorod arrays on unique 3D substrate are expected to improve the sensitivity and efficiency of ZnO based electrochemical sensors and heterogeneous catalysts.

  • 27.
    Khan, Yaqoob
    et al.
    National Centre for Nanotechnology, Department of Metallurgy and Materials Engineering, PIEAS, P.O. Nilore, Islamabad.
    Hussain, Sajjad
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Durrani, Shahid Khan
    Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad.
    Honeycomb β-Ni(OH)2 films grown on 3D nickel foam substrates at low temperature2012In: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 69, p. 37-40Article in journal (Refereed)
    Abstract [en]

    A simple method is presented to grow thick honeycomb β-Ni(OH)2 films on 3D nickel foam substrates at80 °C using nickel sulfate and ammonia as the starting materials. The porous honeycomb network structureof the films with pore openings about 0.5–1 μm wide is built from seamlessly connected polycrystallinenanowalls, approximately 10–20 nm thick. The amount of ammonia added to the growth solution and thegrowth time were found to be critical parameters in determining the morphology and pore structure ofthe films. Air annealing of the as-prepared films resulted in polycrystalline NiO films with morphologiessimilar to those of their hydroxide precursors.

  • 28.
    Klasson, Anna
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ahrén, Maria
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Hellqvist, Eva
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, Faculty of Science & Engineering.
    Rosén, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Positive MRI Enhancement in THP-1 Cells with Gd2O3 Nanoparticles2008In: Contrast Media and Molecular Imaging, ISSN 1555-4309, Vol. 3, no 3, p. 106-111Article in journal (Refereed)
    Abstract [en]

    There is a demand for more efficient and tissue-specific MRI contrast agents and recent developments involve the design of substances useful as molecular markers and magnetic tracers. In this study, nanoparticles of gadolinium oxide (Gd2O3) have been investigated for cell labeling and capacity to generate a positive contrast. THP-1, a monocytic cell line that is phagocytic, was used and results were compared with relaxivity of particles in cell culture medium (RPMI 1640). The results showed that Gd2O3-labeled cells have shorter T1 and T2 relaxation times compared with untreated cells. A prominent difference in signal intensity was observed, indicating that Gd2O3 nanoparticles can be used as a positive contrast agent for cell labeling. The r1 for cell samples was 4.1 and 3.6 s-1 mm-1 for cell culture medium. The r2 was 17.4 and 12.9 s-1 mm-1, respectively. For r1, there was no significant difference in relaxivity between particles in cells compared to particles in cell culture medium, (pr1 = 0.36), but r2 was significantly different for the two different series (pr2 = 0.02). Viability results indicate that THP-1 cells endure treatment with Gd2O3 nanoparticles for an extended period of time and it is therefore concluded that results in this study are based on viable cells.

  • 29.
    Klasson, Anna
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Cell tracking with novel contrast agents fromed by gadolinium oxide nanoparticels2005In: ESMRMB,2005, 2005Conference paper (Refereed)
  • 30.
    Klasson, Anna
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Hellqvist, Eva
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology.
    Rosén, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Cell tracking with positive contrast using Gd2O3 nanoparticles2006In: ESMRMB,2006, 2006Conference paper (Other academic)
  • 31.
    Käll, Per-Olov
    Stockholms Universitet.
    Quantitative Phase Analysis of Si3N4-based Materials1988In: Chemica Scripta, ISSN 0004-2056, Vol. 28, p. 439-446Article in journal (Refereed)
  • 32.
    Käll, Per-Olov
    et al.
    Stockholm University.
    Ekström, Thommy
    Stockholm University.
    Phase Composition and Mechanical Properties of HIP-Sintered Y/Nd-Sialon Ceramics1990In: Proc. 11th Risö Internat. Symp. on Metallurgy and Materials Science / [ed] J.J. Bentzen et al., 1990, p. 383-388Conference paper (Refereed)
    Abstract [en]

    Sialon ceramics were hot isostatic pressed (HIP) at 1820 K, 2050 K and 2100 K using mixtures of Y2O3/Nd2O3 as sintering aids. The overall sialon compositions were selected to obtain either pure beta sialons or mixed alpha-beta sialons with different alpha/beta ratios. The ratio of the Y2O3/Nd2O3 additions was varied from pure yttria to pure neodymia, and the materials have been characterised with respect to phase content, microstructure, chemical composition, Vickers hardness and fracture toughness. The results are compared with those for the same compositions pressureless sintered.

  • 33.
    Käll, Per-Olov
    et al.
    University of Stockholm.
    Ekström, Thommy
    University of Stockholm.
    Sialon Ceramics Made with Mixtures of Y2O3-Nd2O3 as Sintering Aid1990In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 6, no 2, p. 119-127Article in journal (Refereed)
    Abstract [en]

    Sialon ceramics have been prepared by pressureless sintering at 1775 and 1825°C, using mixtures of Y2O3---Nd2O3 as sintering aids. It was found that at 1775°C less dense materials were obtained, but by raising the sintering temperature to 1825°C fully dense materials could be produced, even when pure neodymia was used. The hardness of the Nd-sialon ceramics was found to be slightly lower than for the corresponding Y-sialon ceramics, but the fracture toughness was approximately the same. It was also observed that the amount of intergranular phase increased when yttria was replaced by neodymia.

  • 34.
    Käll, Per-Olov
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Grins, J.
    Department of Inorganic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden.
    Fahlman, Mats
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry .
    Söderlind, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Synthesis, structure determination and X-ray photoelectron spectroscopy characterisation of a novel polymeric silver(I) nicotinic acid complex, H[Ag(py-3-CO2)2]2001In: Polyhedron, ISSN 0277-5387, E-ISSN 1873-3719, Vol. 20, no 21, p. 2747-2753Article in journal (Refereed)
    Abstract [en]

    Polymeric inorganic or organometallic coordination compounds represent an interesting class of materials where novel (combinations of) electrical, optical, magnetic, catalytic, or other properties are expected to occur. It has recently been shown that Ag1 complexes formed by organic N,N'-bidentate type ligands exhibit a rich structural variety encompassing ID, 2D and 3D polymers. Previous investigations of the silver(I) nicotinic acid system have revealed two different structural types, in both of which Ag1 is three-coordinated. We have investigated the system nicotinic acid (C6H5NO2/AgA in water (A = NO3-, CH3COO- and F-). In all the cases the same product precipitated, catena-{hydrogen bis[pyridine-3-carboxylato-(N,N')]silver(I)}, H[Ag(py-3-CO2)2] (M = 353.1 g mol-1). The structure can be described as a 1D polymer consisting of [Ag(C6H4NO2)2]- monomers linked via C21(12)[R21(4)] hydrogen bonds, where the connecting H+ ion is located at the same distance (1.24 Å) to the carboxyl oxygens of consecutive monomers. The measured X-ray photoelectron spectrum shows an excellent agreement with the proposed structure. FTIR measurements of the complex were also performed. © 2001 Elsevier Science Ltd. All rights reserved.

  • 35.
    Käll, Per-Olov
    et al.
    University of Stockholm.
    Grins, Jekabs
    University of Stockholm.
    Nygren, Mats
    University of Stockholm.
    Structure of the Nd U-Phase, Nd3Al3.5Si2.5O12.5N1.5; a Nitrogen-Containing Phase of the La3Ga5GeO14 Structure Type1991In: Acta Crystallographica Section C: Crystal Structure Communications, ISSN 0108-2701, E-ISSN 1600-5759, Vol. 47, no 10, p. 2015-2019Article in journal (Refereed)
    Abstract [en]

     n/a

     

     

     

     

     

     

  • 36.
    Käll, Per-Olov
    et al.
    University of Stockholm.
    Grins, Jekabs
    University of Stockholm.
    Olsson, Per-Olof
    University of Stockholm.
    Liddell, Kath
    University of Stockholm.
    Korgul, Peter
    University of Stockholm.
    Thompson, Derek P.
    University of Stockholm.
    Preparation and Crystal Structure of of U-Phase Ln3(Si3-xAl3+x)O12+xN2-x (x≈0.5, Ln=La,Nd)1991In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 1, no 2, p. 239-244Article in journal (Refereed)
    Abstract [en]

    U-phase Ln3(Si3 –xAl3 +x)O12 +xN2 –x(Ln = La, Nd) occurs as a crystalline phase in rare-earth sialon ceramics formed by devitrification of grain-boundary glasses at 1000–1400 °C. The crystal structure of Nd U-phase has been determined from Cu-Kα X-ray powder diffractometer data and refined by the Rietveld full-profile technique to RF= 0.028. The space group is P321 and the cell dimensions are a= 7.974(1)Å, c= 4.873(1)Å and V= 268.29 Å3. The structure is isomorphic with the La3Ga5GeO14 structure, and exhibits corner-shared layers of (Si,Al)(O,N)4 tetrahedra interconnected by AlO6 octahedra. The rare-earth cations occupy sites between the tetrahedral layers. Transmission electron microscopy and lattice imaging studies support the X-ray structural findings. The structural relationship of the U-phase to other nitrogen-containing ceramic phases is discussed.

  • 37.
    Käll, Per-Olov
    et al.
    Stockholm University.
    Nygren, Mats
    Stockholm University.
    Persson, Jeanette
    Stockholm University.
    Nonparabolic Oxidation Kinetics of Advanced Ceramics1993In: Proc. NATO Conf. on Corrosion of Advanced Materials / [ed] K. Nickel, Dordrecht, The Netherlands: Kluwer Academic Publishers , 1993, p. 73-94Conference paper (Refereed)
  • 38.
    Käll, Per-Olov
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Ojamäe, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Pedersen, Henrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Söderlind, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Petoral, Rodrigo Jr
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Zhang, H.
    Zouc, X.
    Synthesis, Characterisation and Molecular Functionalisation of Gd2O3 Nanocrystals2004In: NAN:-8,2004, 2004Conference paper (Other academic)
    Abstract [en]

      

  • 39.
    Lawrence, David
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Preliminary analysis of metals removal techniques from the fines fraction of contaminated soils: Work completed for SSM AB2002Report (Other (popular science, discussion, etc.))
    Abstract [en]

    Svensk Sjömuddring AB (SSM) is a company that can be contracted to remove metals from contaminated soils, specializing in soils from military sites. The soils are generally contaminated with a wide range of metals, with the most prevalent being Cu, Zn and, the biggest problem, Pb. Typical levels range for a few hundred milligrams per kilogram for Cu and Zn to several grams per kilogram for Pb. Acceptable levels, as defined by Swedish regulations lie around 200 mg/kg, depending upon the metal. SSM has a process for removing these metals, using physical processes (magnetic separation, cyclones, screening, etc.), however, these processes cannot cope with the fraction of the soils with particle size less than 0.5 mm. Currently, this fraction of the soil (which can account for around 40% of the soil) must be taken to a landfill site capable of storing toxic materials. Hence, it was the purpose of this work to evaluate chemical and electrochemical methods for removing Cu, Zn and Pb from the fine fraction of contaminated soils.

  • 40.
    Lenz, Annika
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Selegård, Linnea
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Inorganic Chemistry. Linköping University, Faculty of Science & Engineering.
    Larsson, Arvid
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Ojamäe, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Inorganic Chemistry. Linköping University, The Institute of Technology.
    ZnO Nanoparticles Functionalized with Organic Acids: An Experimental and Quantum-Chemical Study2009In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, no 40, p. 17332-17341Article in journal (Refereed)
    Abstract [en]

    Electrochemical synthesis and physical characterization of ZnO nanoparticles functionalized with four different organic acids, three aromatic (benzoic, nicotinic, and trans-cinnamic acid) and one nonaromatic (formic acid), are reported. The functionalized nanoparticles have been characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, UV−vis, and photoluminescence spectroscopy. The adsorption of the organic acids at ZnO nanoparticles was further analyzed and interpreted using quantum-chemical density-functional theory computations. Successful functionalization of the nanoparticles was confirmed experimentally by the measured splitting of the carboxylic group stretching vibrations as well as by the N(1s) and C(1s) peaks from XPS. From a comparison between computed and experimental IR spectra, a bridging mode adsorption geometry was inferred. PL spectra exhibited a remarkably stronger near band edge emission for nanoparticles functionalized with formic acid as compared to the larger aromatic acids. From the quantum-chemical computations, this was interpreted to be due to the absence of aromatic adsorbate or surface states in the band gap of ZnO, caused by the formation of a complete monolayer of HCOOH. In the UV−vis spectra, strong charge-transfer transitions were observed.

  • 41.
    Lloyd Spetz, Anita
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Buchholt, Kristina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lutic, Doina
    Lunds universitet.
    Strand, M
    Växjö universitet.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Sanati, Mehri
    Lunds universitet.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Multifunctional chemical sensors based on wide band gap materials2007In: MRS Spring Meeting,2007, 2007Conference paper (Refereed)
    Abstract [en]

       

  • 42.
    Lloyd Spetz, Anita
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Eriksson, Jens
    Ehrler, S
    Khranovskyy, Volodymyr
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Gas sensors based on ZnO nanopraticels or film: A comparison2008In: IMCS 12,2008, 2008, p. 89-Conference paper (Refereed)
    Abstract [en]

       

  • 43.
    Lloyd Spetz, Anita
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Pearce, Ruth
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Hedin, Linnea
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    New transducer material concepts for biosensors and surface functionalization2009In: Smart Sensors, Actuators,and MEMS IV / [ed] Ulrich Schmid, Carles Cané, Herbert Shea, Bellingham, WA United States: SPIE - International Society for Optical Engineering, 2009, Vol. 7362, p. 736206-Conference paper (Refereed)
    Abstract [en]

    Wide bandgap materials like SiC, ZnO, AlN form a strong platform as transducers for biosensors realized as e.g. ISFET (ion selective field effect transistor) devices or resonators. We have taken two main steps towards a multifunctional biosensor transducer. First we have successfully functionalized ZnO and SiC surfaces with e.g. APTES. For example ZnO is interesting since it may be functionalized with biomolecules without any oxidation of the surface and several sensing principles are possible. Second, ISFET devises with a porous metal gate as a semi-reference electrode are being developed. Nitric oxide, NO, is a gas which participates in the metabolism. Resistivity changes in Ga doped ZnO was demonstrated as promising for NO sensing also in humid atmosphere, in order to simulate breath.

  • 44.
    Lloyd-Spets, Anita
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Ieva, Eliana
    IFM .
    Cioffi, N.
    Torsi, L.
    Sabbatini, L.
    Zambonin, P.G.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Nanoparticelle di oro come materiali attivi in capacitori impiegati come sensori di gas2006In: Conf. on Chemical Sensors,2006, 2006Conference paper (Refereed)
  • 45.
    Lloyd-Spets, Anita
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Salomonsson, Anette
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Ojamäe, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Strand, M.
    Einvall, J.
    Aulin, C.
    Nanoparticles as sensing material for selective and stable SiC-FET gas sensor2006In: Proc. European Aerosol Conference 2005,2006, 2006, p. 735-735Conference paper (Refereed)
  • 46.
    Lutic, D.
    et al.
    Växjö universitet.
    Strand, M.
    Växjö universitet.
    Salomonsson, Anette
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Ojamäe, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Lloyd-Spets, Anita
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Sanati, M.
    Växjö universitet.
    In2O3 particle films as gate material for MISiC-capacitor sensors2005In: NOSA 2005,2005, 2005Conference paper (Refereed)
  • 47.
    Lutic, Doina
    et al.
    Lunds universitet.
    Strand, Michael
    Dept. of Chemistry, Växjö University.
    Lloyd-Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Buchholt, Kristina
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Ieva, Eliana
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Sanati, Mehri
    Dept. of Chemistry, Växjö University.
    Catalytic properties of oxide nanoparticles applied in gas sensors2007In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 45, no 1-4, p. 105-109Article in journal (Refereed)
    Abstract [en]

    A series of gas sensing layers based on indium oxide doped with gold were prepared by using the aerosol technology fordeposition as the active contact layer in a metal oxide semiconductor capacitive device. The interaction between the measuredspecies and the insulator surface was quantified as the voltage changes at a constant capacitance of the device. The sensor propertieswere investigated in the presence of H2, CO, NH3, NO, NO2 and C3H6 at temperatures between 100–400 oC. Significant differencesin the morphology of the layer and its sensitivity were noted for different preparation methods and different gas environments.

  • 48. Nilsson, Mattias
    et al.
    Grins, Jekabs
    Dept. Physical, Inorganic and Structural Chemistry, Stockholm University.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Svensson, Gunnar
    Dept. Physical, Inorganic and Structural Chemistry, Stockholm University.
    Synthesis, structural characterization and magnetic properies of Gd14W4O33-xNy (0≤x≤17, 0≤y≤9), a new fluorite-related oxynitride1996In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 240, no 1-2, p. 60-69Article in journal (Refereed)
    Abstract [en]

    A series of crystalline Cd-W oxides. with Gd:W ratios spanning the values 0.1-3.5. has heen prepared and treated with a flow of NH3(g) in the temperature range 700-1100 oC. Besides the previously reported formation of GdWO3N and Gd2WO3N2. the following new results were obtained: (I) cubic Gd0.1WO3 upon ammonolysis forms an (oxy)nitride Gd0.1x W(O. N) with an f.c.c lattice; (ii) the previously described Gd2WO3N2 exhibits a solid solubility range Gd3-xW1+x(O.N)y with, approximately, 0≤x≤1; (iii) ammonolysis of Gd14W4O33 yields an oxynitride, the composition of which varies with the synthesis temperature according to Gd14W4O33-xNy (0≤x≤17±2, 0≤y≤9±2). All strong diffraction lines, including those of the pure oxide (x =y= 0), can be indexed with a body-centred monoclinic unit cell derived from that of fluorite. For Gd14W4O33 the cell parameters are a = 5.3592(11), b = 3.7295(7), c = 3.8636(8), β = 92.170(2)o and V = 77.17 Å3. However, strong superstructure rereflections in the electron diffraction patterns indicate that the true unit cell is considerably larger. A partial structur determination of Gd14W4O33-xNy has been carried out by the Rierveld method. Magnetic susceptibility measurements in the temperature interval 15-300 K show a Curie-Weiss behaviour for Gd14W4O33-xNy with μeff = 8.08±0.06 Bohr magnetons per Gd3+ and θ = −12.4±1.1 K for all compositions.

  • 49.
    Nordberg, Lars-Olof
    et al.
    Stockholm University.
    Käll, Per-Olov
    Stockholm University.
    Nygren, Mats
    Stockholm University.
    A Mathematical Analysis of the Non-Parabolic Oxidation Behaviour of α-Sialon Matrices and Composites1996In: Key Engineering Materials Vol. 113, Switzerland: Trans Tech Publications , 1996, p. 39-48Conference paper (Refereed)
  • 50.
    Nordberg, Lars-Olov
    et al.
    Stockholm University.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Nygren, Mats
    Dept. Physical, Inorganic and Structural Chemistry, Stockholm University.
    Shen, Zhijian
    Dept. Physical, Inorganic and Structural Chemistry, Stockholm University.
    Stability and oxidation properties of RE–α-Sialon ceramics (RE = Y, Nd, Sm, Yb)1998In: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 81, no 6, p. 1461-1470Article in journal (Refereed)
    Abstract [en]

    Oxidation studies of hot-pressed RE–α-sialons, REx-Si12−4.5xAl4.5xO1.5xN16−1.5x (with x = 0.40 for RE = Nd, Sm,Yb; and x = 0.48 for RE = Y) were carried out in oxygen in a TG apparatus for ca. 20 h. Very good oxidation resistance was found for the Yb-doped samples, with parabolic rateconstants Kp ≈ 0.09 × 10−6–3 × 10−6 mg2 cm−4 s−1 in the temperature range 1250–1350°C. The promising performance of this material was corroborated by long-term oxidation experiments (5 days) in air at 1350°C. Although the oxidation kinetics can be described by simple equations related to the parabolic rate law (e.g., the arctan equation, ΔW/Ao = α·arctan(bt)½+ct½), the oxidation process in these materials is likely to be complex. The significantly lower oxidation resistance of the RE = Nd, Sm doped α-sialons, especially at higher temperatures, is related to the formation of melilite, RE2Si3−yAlyO3+yN4−y (y ≈ 1), in these systems. The melilite phase is also responsible for the thermal instability of the Nd– and Sm–α-sialons.

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