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  • 51.
    Anzellini, S.
    et al.
    Diamond Light Source Ltd., Diamond House, Harwell Science Campus, Didcot, Oxfordshire, United Kingdom.
    Errandonea, D.
    Departamento de Física Aplicada-Instituto de Ciencia de Materiales, Matter at High Pressure (MALTA) Consolider Team, Universidad de Valencia, Edificio de Investigación, Valencia, Spain.
    MacLeod, S. G.
    AWE, Aldermaston, Reading, United Kingdom. SUPA, School of Physics and Astronomy, and Centre for Science at Extreme Conditions,The University of Edinburgh, Edinburgh, United Kingdom.
    Botella, Pablo
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Daisenberger, D.
    Diamond Light Source Ltd., Diamond House, Harwell Science Campus, Didcot, Oxfordshire, United Kingdom.
    De’Ath, M.
    AWE, Aldermaston, Reading, United Kingdom.
    Gonzalez-Platas, J.
    Departmento de Física, Universidad de La Laguna, Avda. Astrofísico Fco. Sánchez s/n, Tenerife, Spain.
    Ibáñez, J.
    Institute of Earth Sciences Jaume Almera, CSIC, Barcelona, Spain.
    McMahon, M. I.
    SUPA, School of Physics and Astronomy, and Centre for Science at Extreme Conditions,The University of Edinburgh, Edinburgh, United Kingdom.
    Munro, K. A.
    SUPA, School of Physics and Astronomy, and Centre for Science at Extreme Conditions,The University of Edinburgh, Edinburgh, United Kingdom.
    Popescu, C.
    CELLS-ALBA Synchrotron Light Facility, Barcelona, Spain.
    Ruiz-Fuertes, J.
    DCITIMAC, MALTA Consolider Team, Universidad de Cantabria, Santander, Spain.
    Wilson, C. W.
    AWE, Aldermaston, Reading, United Kingdom.
    Phase diagram of calcium at high pressure and high temperature2018Inngår i: Physical review materials, ISSN 2475-9953, Vol. 2, nr 8, artikkel-id 083608Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Resistively heated diamond-anvil cells have been used together with synchrotron x-ray diffraction to investigate the phase diagram of calcium up to 50 GPa and 800 K. The phase boundaries between the Ca-I (fcc), Ca-II (bcc), and Ca-III (simple cubic, sc) phases have been determined at these pressure-temperature conditions, and the ambient temperature equation of state has been generated. The equation of state parameters at ambient temperature have been determined from the experimental compression curve of the observed phases by using third-order Birch-Murnaghan and Vinet equations. A thermal equation of state was also determined for Ca-I and Ca-II by combining the room-temperature Birch-Murnaghan equation of state with a Berman-type thermal expansion model.

  • 52.
    Arora, Kapildev K.
    et al.
    Solid State & Supramolecular Structural Chemistry Unit, Division of Organic Chemistry, National Chemical Laboratory.
    Talwelkarshimpi, Mayura
    Solid State & Supramolecular Structural Chemistry Unit, Division of Organic Chemistry, National Chemical Laboratory.
    Pedireddi, V.R.
    Solid State & Supramolecular Structural Chemistry Unit, Division of Organic Chemistry, National Chemical Laboratory.
    Supramolecular synthesis of some molecular adducts of 4,4′-bipyridine N,N′-dioxide2009Inngår i: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 33, nr 1, s. 57-63Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Molecular adducts (1a–1e) of 4,4′-bipyridine N,N′-dioxide, 1, respectively with cyanuric acid, trithiocyanuric acid, 1,3,5-trihydroxybenzene (phloroglucinol), 1,3-dihydroxybenzene (resorcinol) and 1,2,4,5-benzenetetracarboxylic acid have been reported. The major interactions observed in the structures 1a–1e are N–H⋯O, N–H⋯S, O–H⋯O and C–H⋯O, in the form of homomeric and heteromeric patterns of the constituents, either as a single or cyclic hydrogen-bonded motifs. While in the adduct 1a, both homomeric and heteromeric units of both the constituents were observed, no heteromeric interactions were observed in 1b and 1c. In addition, in 1b, homomeric aggregation of molecules of 1 occurred in association with water molecules. However, while heteromeric interactions prevail between the constituents in 1d and 1e, only one of the co-crystallizing species gave homomeric interactions (4,4′-bipyridine N,N′-dioxide in 1d; 1,2,4,5-benzenetetracarboxylic acid in 1e). Further, in either type of the patterns, the cyclic motifs are formed as a pair-wise hydrogen bonds comprising of strong and weak hydrogen bonds (N–H⋯O/C–H⋯O or O–H⋯O/C–H⋯O). In three-dimensions, the ensembles of molecules yield planar sheets, ladders and pseudorotaxane type assemblies

  • 53. Arvanitidis, J.
    et al.
    Meletov, K. P.
    Kourouklis, G. A.
    Papagelis, K.
    Soldatov, Alexander
    Prassides, K.
    Ves, S.
    High pressure study of the 2D polymeric phase of C60 by means of Raman spectroscopy2001Inngår i: High Pressure Research, ISSN 0895-7959, E-ISSN 1477-2299, Vol. 18, nr 1-6, s. 145-151Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of high hydrostatic pressure, up to 12GPa, on the intramolecular phonon frequencies and the material stability of the two-dimensional tetragonal Cm polymer has been studied by means of Raman spectroscopy in the spectral range of the radial intramolecular modes (200-800cm-1). A number of new Raman modes appear in the spectrum for pressures ≈ 1.4 and ≈ 5.0 GPa. The pressure coefficients for the majority of the phonon modes exhibit changes to lower values at P=4.0 GPa, which may be related to a structural modification of the 2D polymer to a more isotropic phase. The peculiarities observed in the Raman spectra are reversible and the material is stable in the pressure region investigated.

  • 54. Arvanitidis, J.
    et al.
    Meletov, K.P.
    Papagelis, K.
    Soldatov, Alexander
    Prassides, K.
    Kourouklis, G. A.
    Ves, S.
    Comparative Raman study of the 1D and 2D polymeric phases of C60 under pressure1999Inngår i: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 215, nr 1, s. 443-448Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of symmetry lowering on the phonon spectra as well as the pressure effects on the vibrational spectrum of polymerized C60 were studied by Raman spectroscopy. Drastic changes related to the splitting of degenerate modes of the C60 molecule were observed together with selected softening of some of them. In spite of many similarities in the Raman spectra of the one- (1D) and two-dimensional (2D) polymeric forms of C60, some salient differences in the peak intensities and the appearance of complementary modes are evident. In the Raman spectrum of the 2D polymer under high pressure, new modes, which may be related to the deformations of molecular cages, appear. The observed pressure effects are reversible and the material remains stable for pressures up to 8.8 GPa.

  • 55. Arvantidis, J.
    et al.
    Meletov, K.P.
    Papagelis, K.
    Ves, S.
    Kourouklis, G. A.
    Soldatov, Alexander
    Prassides, K.
    Raman modes of the two-dimensional tetragonal polymeric phase of C60 under high pressure2001Inngår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 114, nr 20, s. 9099-9104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of high hydrostatic pressure, up to 12 GPa, on the phonon spectrum and the material stability of the two-dimensional (2D) tetragonal C60 polymer have been studied by means of Raman spectroscopy in the frequency range 100-2000 cm-1. A number of Raman modes appear in the spectrum for pressures above ~1.4 GPa, whose intensities increase with pressure. The pressure coefficients of the majority of the phonon modes change gradually to lower values for pressures around 4.0 GPa. The deformation of the C60 molecular cage along with the change of the material to a more isotropic state (as far as its elastic properties are concerned) resulting from the application of high pressure may be causing the observed effects in the Raman spectra. These effects are reversible upon pressure release and therefore the material is stable in the pressure region investigated.

  • 56.
    Arve, Per
    et al.
    Luleå tekniska universitet.
    Helgesson, J.
    Luleå tekniska universitet.
    The NN-1, π and ΔN-1 delta decay modes in the nuclear medium1994Inngår i: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 572, nr 3-4, s. 600-620Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The dependence of the Δ-width on the Δ-decay channels is studied in the nuclear medium. We calculate the decay of the delta into a nucleon and a general pisobar mode consisting of NN-1-, π- and dN-1-modes. For the case of no width of the Δ in the pisobar we present partial contributions to the Δ-width from the Δ-decay channels: Δ→N+NN-1, Δ→N+π and Δ→N+ΔN-1. Results for a self-consistent treatment of the Δ-width in the pisobar is presented. The self-consistent treatment only modifies the results with no width in the pisobar to a small extent. It is found that NN-1 channel is not only dominating the decay at low energies of the Δ-resonance but at high densities (ρ>1.5ρ0) this channel also dominates the decay at higher energies. Qualitative agreement with inclusive and exclusive (p,n) and (3He,T) experiments is achieved

  • 57.
    Avakyan, Leon
    et al.
    Department of Physics and I3N, University of Aveiro, Aveiro, Portugal.
    Paramonova, Ekaterina
    Institute of Mathematical Problems of Biology, Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, 142290 Moscow Region, Russian Federation.
    Coutinho, José
    Department of Physics and I3N, University of Aveiro, Aveiro, Portugal.
    Öberg, Sven
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Bystrov, Vladimir
    Institute of Mathematical Problems of Biology, Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, 142290 Moscow Region, Russian Federation.
    Bugaev, Lusegen
    Physics Faculty, Southern Federal University, Rostov-on-Don 344090, Russian Federation.
    Optoelectronics and defect levels in hydroxyapatite by first-principles2018Inngår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 148, nr 15, artikkel-id 154706Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydroxyapatite (HAp) is an important component of mammal bones and teeth, being widely used in prosthetic implants. Despite the importance of HAp in medicine, several promising applications involving this material (e.g., in photo-catalysis) depend on how well we understand its fundamental properties. Among the ones that are either unknown or not known accurately, we have the electronic band structure and all that relates to it, including the bandgap width. We employ state-of-the-art methodologies, including density hybrid-functional theory and many-body perturbation theory within the dynamically screened single-particle Green's function approximation, to look at the optoelectronic properties of HAp. These methods are also applied to the calculation of defect levels. We find that the use of a mix of (semi-)local and exact exchange in the exchange-correlation functional brings a drastic improvement to the band structure. Important side effects include improvements in the description of dielectric and optical properties not only involving conduction band (excited) states but also the valence. We find that the highly dispersive conduction band bottom of HAp originates from anti-bonding σ* states along the ⋯OH-OH-⋯ infinite chain, suggesting the formation of a conductive 1D-ice phase. The choice of the exchange-correlation treatment to the calculation of defect levels was also investigated by using the OH-vacancy as a testing model. We find that donor and acceptor transitions obtained within semi-local density functional theory (DFT) differ from those of hybrid-DFT by almost 2 eV. Such a large discrepancy emphasizes the importance of using a high-quality description of the electron-electron interactions in the calculation of electronic and optical transitions of defects in HAp.

  • 58. Axelsson, O.
    et al.
    Paul, Jan
    Weisel, M.D.
    Hoffmann, F,M.
    Reactive evaporation of potassium in CO2 and the formation of bulk intermediates1994Inngår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 12, nr 1, s. 158-160Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Potassium vapor condensed in CO2 has been studied by transmission infrared spectroscopy and by total pressure thermal desorption spectroscopy. The results are compared with surface spectroscopic data for CO2 adsorbed on alkali metal overlayers. Both systems show the formation of bulk coordinated oxalate species at cryogenic temperatures and the conversion to carbonate intermediates upon annealing.

  • 59. Axelsson, O.
    et al.
    Shao, Y.
    Paul, Jan
    Hoffmann, F.M.
    A theoretical and experimental study of reaction pathways for the interaction of CO2 with alkali-modified surfaces1995Inngår i: Journal of Physical Chemistry, ISSN 0022-3654, Vol. 99, nr 18, s. 7028-7035Artikkel i tidsskrift (Fagfellevurdert)
  • 60.
    Aycik, G.A.
    et al.
    Turkish Atomic Energy Authority, Ankara Nuclear Research and Training Center.
    Paul, M.
    Turkish Atomic Energy Authority, Ankara Nuclear Research and Training Center.
    Sandström, Åke
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Paul, Jan
    Leaching of radioactive isotopes from ash2003Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The aim of the study is to reduce the environmental impact of ash deposits. Ash from coal and biomass combustion, containing uranium and thorium from Yatagan-Silopi and Tuncbilek coal; cesium-137 from forests in northeastern Turkey and central Sweden. Turkey is dependent on coal for power generation and huge volumes of ash (>15 Mton/yr) are produced every year. Because of that certain coals, in particular Yatagan, with known problems from Mo and U leaching to the ground water, and Silopi oil shales/asphaltites were studied. Biomass ash comes from branches, bark and other unused parts of the trees and plants. This ash has low concentration of environmentally hazardous metals, but {sup 137}Cs is a problem in certain regions and it is of interest to investigate the possibilities to leach this metal from the ash. Washing ash through rapid chemical leaching at low pH reduces the slow release of metals from ash due to precipitation and besides it may lead to metal recovery from the ash. Initial experiments were done in batch form, in which the neutralizing capacity at pH 1-1.5 was measured by adding sulfuric acid to maintain pH for mixtures of ash and water. Subsequent experiments were done in bench scale. The process also reduced the metal content of the ash, due to chemical leaching of metal oxides and ion exchange at the surfaces of stable oxides. This means that treated ash will not release further metals and, eventually, relaxes the requirements on depositories and allows the ash from coal to be used as an admixture in cement, and to be used as a fertilizer following after treatment of ash from biomass

  • 61.
    Baran, Jakub D.
    et al.
    School of Chemistry, University of Bath.
    Jarvis, Samuel P.
    School of Physics and Astronomy, University of Nottingham.
    Taylor, Simon
    School of Physics and Astronomy, University of Nottingham.
    Thompson, Damien
    Department of Physics and Energy, Materials and Surface Science Institute, University of Limerick.
    Saywell, Alex
    Fritz Haber Institute of the Max-Planck Society.
    Mangham, Berry
    School of Chemistry, the University of Nottingham.
    Champness, Neil R.
    School of Chemistry, the University of Nottingham.
    Moriarty, Philip
    School of Physics and Astronomy, University of Nottingham.
    Larsson, Andreas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    A Case of Unusually Large Density of States Changes For Physisorption - TetraPhenyl-Porphyrins on Cu(111)2015Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Conformational changes caused by surface adsorption can dramatically affect a molecule’s properties. The conformational flexibility of the porphyrin family of molecules has been exploited particularly well in a number of contexts, including prototypical molecular switches. Despite this level of study, however, the exact mechanisms underpinning conformational switching are often unclear. We show that the conformation of the tetra(4-bromophenyl) porphyrin (Br4TPP) on Cu(111) depends critically on the precise adsorption site of the molecule, and that, remarkably, large conformational changes are driven entirely by van der Waals (vdW) interactions between the molecule and the substrate surface. A combination of scanning probe microscopy, low temperature single molecule manipulation, dispersion-corrected density functional theory (DFT) and molecular dynamics (MD) simulations shows that van der Waals forces dominate the adsorption of TPP molecules, causing significant distortions of the molecular architecture so that the porphyrin can adopt one of two low energy conformations. In addition, scanning probe manipulation has been used to translate and switch the Br4TPP molecule between conformations via an intermediary, ‘hybrid’ structure. We have used the generalized gradient approximation (GGA) parameterization by Perdew—Burke—Ernzerhof (PBE), and the sparse-matter optBP86b-vdW20 (vdW-DFT) exchange and correlation functional to account for the missing dispersion forces. In order to check for the presence of chemical bonding we have analyzed the molecule-surface complexes using electron localization function (ELF) and Bader charges. We find that vdW-forces alone are capable of causing large shifts in the molecular density of states, despite the complete absence of chemical interactions.

  • 62.
    Baran, Jakub D.
    et al.
    Tyndall National Institute, University College Cork.
    Kołodziejczyk, Wojciech
    Tyndall National Institute, University College Cork.
    Larsson, Peter O.
    Division of Materials Theory, Department of Physics and Astronomy, Uppsala University.
    Ahuja, Rajeev B.
    Division of Materials Theory, Department of Physics and Astronomy, Uppsala University.
    Larsson, Andreas
    On the stability of single-walled carbon nanotubes and their binding strengths2012Inngår i: Theoretical Chemistry accounts, ISSN 1432-881X, E-ISSN 1432-2234, Vol. 131, nr 9, s. 1-8Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have studied the relative stability of hydrogen-terminated single-walled carbon nanotubes (SWNTs) segments, and open-ended SWNT fragments of varying diameter and chirality that are present at the interface of the catalytic metal particles during growth. We have found that hydrogen-terminated SWNTs differ by <1 eV in stability among different chiralities, which presents a challenge for selective and property-controlled growth. In addition, both zigzag and armchair tubes can be the most stable chirality of hydrogen-terminated SWNTs, which is a fundamental obstacle for property-controlled growth utilizing thermodynamic stability. In contrast, the most armchair-like open-ended SWNTs segments are always the most stable ones, followed in sequence by chiral index up to the least stable zigzag segments. We explain the ordering by triple bond stabilization of the carbon dangling bonds at the open ends, which is a fragment stabilization effect that is only manifested when all bonds between two layers are broken. We show convincingly that the bond strength difference between zigzag and armchair tubes is not present when individual bonds are broken or formed

  • 63.
    Baran, Jakub D.
    et al.
    Tyndall National Institute, University College Cork.
    Larsson, Andreas
    Structure and energetics of shuttlecock-shaped tin-phthalocyanine on Ag(111: A density functional study employing dispersion correction2012Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, s. 9487-9497Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The reversible switch between two electronically and/or geometrically distinct states of a single molecule adsorbed on a well-characterized substrate is of high technological interest due to its possible use as single molecule devices and novel molecular memories. We have studied shuttlecock-shaped metal phthalocyanines, which can adsorb on surfaces in two distinct adsorption configurations, depending on if the central metal atom points toward or away from the surface, and we report on the adsorption of tin-phthalocyanine (SnPc) on an Ag(111) surface using density functional theory (DFT) including a semiempirical dispersion correction (DFT-D).We discuss the binding mechanism in detail and show that the adsorption of SnPc in these two orientations is driven by very different interactions. While "Sn-down" adsorption involves chemical bonding between Sn and the surface (chemisorption), the "Sn-up" configuration is bound only by weak van der Waals forces (physisorption). By comparing our theoretical results with a broad range of experimental data, we assess the effect of dispersion forces for the SnPc/Ag(111) system and how these impact adsorption energies, geometries, and the electronic structure. We show that an inclusion of dispersion forces improves the adsorption geometry with respect to experiment and is essential in order to capture the subtle electronic effects at molecule-metal interfaces. By analyzing the geometric and electronic structure of the adsorbed molecules we, in addition, shed light on the surprising 2-fold symmetry reduction of metal phthalocyanine molecules that has been observed upon adsorption on surfaces

  • 64.
    Baran, Jakub D.
    et al.
    Tyndall National Institute, University College Cork.
    Larsson, Andreas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Theoretical insights into adsorption of cobalt phthalocyanine on Ag(111): A combination of chemical and van der Waals bonding2013Inngår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 117, nr 45, s. 23887-23898Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this article we study in detail the interaction of cobalt phthalocyanine (CoPc) with the Ag(111) surface by means of density functional theory calculations (DFT). We discuss the electronic and geometric differences of the adsorbed CoPc as it interacts with the different binding sites of the surface, yielding deeper insight into the adsorption mechanism of organometallic molecules with noble metal surfaces. We interpret the experimentally observed 4-fold to 2-fold symmetry reduction upon interaction of phthalocyanine molecules with metal surfaces as caused by electronic effects originating from nonsymmetric interactions between the molecule and the surface. To asses the role of dispersion forces in bonding of CoPc to the surface we employ a semiempirical dispersion correction to standard DFT and compare the obtained molecule-surface separation with experimental measurements. We show that, in the case of CoPc, the molecule bonds to the surface mostly due to covalent bonding between Co and Ag, but with a considerable contribution from van der Waals bonding between the Pc ligand and the surface. We show in this case where the molecule-surface separation is mostly governed by covalent bonding between the central metal atom and the surface atoms that standard DFT performs reasonably well, as compared to the available experimental data.

  • 65.
    Baratto, Camilla
    et al.
    University of Brescia.
    Comini, Elisabetta
    University of Brescia.
    Faglia, Guido
    University of Brescia.
    Ferroni, Matteo
    University of Brescia.
    Ponzoni, Andrea
    University of Brescia.
    Vomiero, Alberto
    University of Brescia, CNR-INFM SENSOR Laboratory.
    Sberveglieri, Giorgio
    University of Brescia.
    Transparent Metal Oxide Semiconductors as Gas Sensors2010Inngår i: Transparent Electronics: From Synthesis to Applications, John Wiley and Sons , 2010, s. 417-442Kapittel i bok, del av antologi (Fagfellevurdert)
  • 66. Baricordi, S.
    et al.
    Biryukov, V. M.
    Institute for High Energy Physics.
    Carnera, A.
    Chesnokov, Yu A.
    Institute for High Energy Physics.
    Mea, G. Della
    University of Trento, Department of Materials Engineering and Industrial Technologies.
    Guidi, V.
    Ivanov, Yu M.
    Petersburg Institute for Nuclear Physics.
    Martinelli, G.
    Milan, E.
    Restello, S.
    INFN.
    Sambo, A.
    Scandale, W.
    CERN.
    Vomiero, Alberto
    Department of Physics, University of Padova.
    Low-energy-channeling surface analysis on silicon crystals designed for high-energy-channeling in accelerators2005Inngår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 87, nr 9, artikkel-id 94102Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Channeling of relativistic particles in bent Si crystals is a powerful technique for use with accelerators. Its efficiency can be found to be highly dependent on the state of the surface of the crystal steering the particles. We investigated the morphology and structure of the surface of the samples that have been used with high efficiency for channeling in accelerators. Low-energy channeling of 2 MeVα particles or protons was used as a probe. We found that mechanical treatment of the samples leads to a superficial damaged layer, which is correlated to efficiency limitations of the crystal in accelerators. In contrast, chemical etching, which was used to treat the surface of the most efficient crystals, leaves a surface with superior perfection. © 2005 American Institute of Physics.

  • 67.
    Basu, Kaustubh
    et al.
    Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications, Université du Québec, Varennes.
    Benetti, Daniele
    Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications, Université du Québec, Varennes.
    Zhao, Haiguang
    Institut National de la Recherche Scientifique Energie Varennes, Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications, Université du Québec, Varennes.
    Jin, Lei
    Institut National de la Recherche Scientifique Energie Varennes, Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications, Université du Québec, Varennes.
    Vetrone, Fiorenzo
    Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications, Université du Québec, Varennes.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Rosei, Frederico
    Institut National de la Recherche Scientifique Energie Varennes, Institut National de la Recherche Scientifique-Énergie, Matériaux et Télécommunications, Université du Québec, Varennes.
    Enhanced photovoltaic properties in dye sensitized solar cells by surface treatment of SnO2 photoanodes2016Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, artikkel-id 23312Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report the fabrication and testing of dye sensitized solar cells (DSSC) based on tin oxide (SnO2) particles of average size ~20 nm. Fluorine-doped tin oxide (FTO) conducting glass substrates were treated with TiOx or TiCl4 precursor solutions to create a blocking layer before tape casting the SnO2 mesoporous anode. In addition, SnO2 photoelectrodes were treated with the same precursor solutions to deposit a TiO2 passivating layer covering the SnO2 particles. We found that the modification enhances the short circuit current, open-circuit voltage and fill factor, leading to nearly 2-fold increase in power conversion efficiency, from 1.48% without any treatment, to 2.85% achieved with TiCl4 treatment. The superior photovoltaic performance of the DSSCs assembled with modified photoanode is attributed to enhanced electron lifetime and suppression of electron recombination to the electrolyte, as confirmed by electrochemical impedance spectroscopy (EIS) carried out under dark condition. These results indicate that modification of the FTO and SnO2 anode by titania can play a major role in maximizing the photo conversion efficiency

  • 68.
    Bathen, M. E.
    et al.
    Department of Physics/Centre for Materials Science and Nanotechnology, University of Oslo, Oslo, Norway.
    Coutinho, J.
    Department of Physics and I3N, University of Aveiro, Campus Santiag, Aveiro, Portugal.
    Ayedh, H. M.
    Department of Physics/Centre for Materials Science and Nanotechnology, University of Oslo, Oslo, Norway.
    Hassan, J. Ul
    Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.
    Farkas, I.
    Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.
    Öberg, Sven
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Frodason, Y. K.
    Department of Physics/Centre for Materials Science and Nanotechnology, University of Oslo, Oslo, Norway.
    Svensson, B. G.
    Department of Physics/Centre for Materials Science and Nanotechnology, University of Oslo, Oslo, Norway.
    Vines, L.
    Department of Physics/Centre for Materials Science and Nanotechnology, University of Oslo, Oslo, Norway.
    Anisotropic and plane-selective migration of the carbon vacancy in SiC: Theory and experiment2019Inngår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 100, nr 1, artikkel-id 014103Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate the migration mechanism of the carbon vacancy (VC) in silicon carbide (SiC) using a combination of theoretical and experimental methodologies. The VC, commonly present even in state-of-the-art epitaxial SiC material, is known to be a carrier lifetime killer and therefore strongly detrimental to device performance. The desire for VC removal has prompted extensive investigations involving its stability and reactivity. Despite suggestions from theory that VC migrates exclusively on the C sublattice via vacancy-atom exchange, experimental support for such a picture is still unavailable. Moreover, the existence of two inequivalent locations for the vacancy in 4H-SiC [hexagonal, VC(h), and pseudocubic, VC(k)] and their consequences for VC migration have not been considered so far. The first part of the paper presents a theoretical study of VC migration in 3C- and 4H-SiC. We employ a combination of nudged elastic band (NEB) and dimer methods to identify the migration mechanisms, transition state geometries, and respective energy barriers for VC migration. In 3C-SiC, VC is found to migrate with an activation energy of EA=4.0 eV. In 4H-SiC, on the other hand, we anticipate that VC migration is both anisotropic and basal-plane selective. The consequence of these effects is a slower diffusivity along the axial direction, with a predicted activation energy of EA=4.2 eV, and a striking preference for basal migration within the h plane with a barrier of EA=3.7 eV, to the detriment of the k-basal plane. Both effects are rationalized in terms of coordination and bond angle changes near the transition state. In the second part, we provide experimental data that corroborates the above theoretical picture. Anisotropic migration of VC in 4H-SiC is demonstrated by deep level transient spectroscopy (DLTS) depth profiling of the Z1/2 electron trap in annealed samples that were subject to ion implantation. Activation energies of EA=(4.4±0.3) eV and EA=(3.6±0.3) eV were found for VC migration along the c and a directions, respectively, in excellent agreement with the analogous theoretical values. The corresponding prefactors of D0=0.54cm2/s and 0.017cm2/s are in line with a simple jump process, as expected for a primary vacancy point defect.

  • 69.
    Battie, Yann
    et al.
    LCP-A2MC, Université de Lorraine.
    Dossot, Manuel
    Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, Nancy Université, Laboratoire de Chimie Physique et Microbiologie pour l'Environnement, UMR 7564, CNRS–University of Lorraine, LCPME UMR 7564 CNRS-Université de Lorraine.
    Allali, Naoual
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Mamane, Victor
    Laboratoire de Synthèse Organométallique et Réactivité, Université Henri Poincaré - Nancy, Laboratoire de Structure et Réactivité des Systèmes Moléculaires Complexes, Nancy Université, SRSMC UMR 7565 CNRS-Université de Lorraine, Faculté des Sciences et Techniques.
    Naciri, Aotmane En
    LCP-A2MC, Université de Lorraine.
    Broch, Laurent
    LCP-A2MC, Université de Lorraine.
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Mild covalent functionalization of single-walled carbon nanotubes highlighted by spectroscopic ellipsometry2016Inngår i: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 96, s. 557-564Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Single-walled carbon nanotubes (SWCNT) synthesized using the HiPco® process and purified thereafter were submitted to two covalent functionalization processes: i) a mild oxidation in a concentrated HNO3 solution using microwave irradiation and ii) a radical functionalization to graft methoxyphenyl groups. The samples were analyzed by Raman spectroscopy and spectroscopic ellipsometry in the energy window 0.07-4.96 eV. The complex dielectric function was analytically calculated in order to extract the real (εr) and imaginary (εi) parts of this function vs. the incident energy of the light. The ellipsometric data in the infrared part of the spectrum revealed that process i) mainly affected the amorphous carbon deposited on the surface of SWCNTs while process ii) strongly changed the electronic nature of the film due to a charge transfer between methoxyphenyl groups and SWCNTs. These results demonstrate the richness of information that spectroscopic ellipsometry is able to bring about on an entire carbon nanotube ensemble compared to Raman spectroscopy, while not suffering from limitation on their electronic structure and/or aggregate state/presence of surfactants.

  • 70.
    Beek, C. J. van der
    et al.
    Laboratoire des Solides Irradiés, CNRS-UMR 7642 & CEA/DSM/DRECAM, Ecole Polytechnique, Palaiseau cedex.
    Klein, Thierry
    Institut Néel, Grenoble.
    Brusetti, René
    Institut Néel, Grenoble.
    Marcenat, Christophe
    Commissariat à l'Energie Atomique, Grenoble.
    Wallin, Mats
    Kungliga tekniska högskolan, KTH.
    Teitel, S.
    University of Rochester.
    Weber, Hans
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Thermodynamics of a heavy-ion-irradiated superconductor: the zero-field transition2007Inngår i: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 75, nr 10Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Specific heat measurements show that the introduction of amorphous columnar defects considerably affects the transition from the normal to the superconducting state in zero magnetic field. Experimental results are compared to numerical simulations of the three-dimensional XY model for both the pure system and the system containing random columnar disorder. The numerics reproduce the salient features of experiment, showing in particular that the specific heat peak changes from cusplike to smoothly rounded when columnar defects are added. By considering the specific heat critical exponent α, we argue that such behavior is consistent with recent numerical work [A. Vestergren et al., Phys. Rev. B 70, 054508 (2004)] showing that the introduction of columnar defects changes the universality class of the transition.

  • 71.
    Bemmerer, D.
    et al.
    INFN.
    Confortola, F.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Lemut, A.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Bonetti, R.
    Istituto di Fisica Generale Applicata.
    Broggini, C.
    INFN.
    Corvisiero, P.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Costantini, H.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Cruz, J.
    Centro de Fısica Nuclear da Universidade de Lisboa.
    Formicola, A.
    Laboratori Nazionali del Gran Sasso.
    Fülöp, Zs
    Institute of Nuclear Research (ATOMKI), Debrecen.
    Gervino, G.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Guglielmetti, A.
    Istituto di Fisica Generale Applicata.
    Gustavino, C.
    Laboratori Nazionali del Gran Sasso.
    Gyürky, Gy
    Institute of Nuclear Research (ATOMKI), Debrecen.
    Imbriani, G.
    Dipartimento di Scienze Fisiche, Universitá Federico II.
    Jesus, A. P.
    Centro de Fısica Nuclear da Universidade de Lisboa.
    Junker, M.
    Laboratori Nazionali del Gran Sasso.
    Limata, B.
    Dipartimento di Scienze Fisiche, Universitá Federico II.
    Menegazzo, R.
    INFN.
    Prati, P.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Roca, V.
    Dipartimento di Scienze Fisiche, Universitá Federico II.
    Rogalla, D.
    Seconda Università di Napoli.
    Rolfs, C.
    Institut Für Experimentalphysik III.
    Romano, M.
    Dipartimento di Scienze Fisiche, Universitá Federico II.
    Alvarez, C. Rossi
    INFN.
    Vomiero, Alberto
    INFN Laboratori Nazionali di Legnaro.
    Feasibility of low-energy radiative-capture experiments at the LUNA underground accelerator facility2005Inngår i: European Physical Journal A, ISSN 1434-6001, E-ISSN 1434-601X, Vol. 24, nr 2, s. 313-319Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The LUNA (Laboratory Underground for Nuclear Astrophysics) facility has been designed to study nuclear reactions of astrophysical interest. It is located deep underground in the Gran Sasso National Laboratory, Italy. Two electrostatic accelerators, with 50 and 400 kV maximum voltage, in combination with solid and gas target setups allowed to measure the total cross-sections of the radiative-capture reactions 2H2H(p, γ) 3He3Heand 14N14N(p, γ) 15O15Owithin their relevant Gamow peaks. We report on the gamma background in the Gran Sasso laboratory measured by germanium and bismuth germanate detectors, with and without an incident proton beam. A method to localize the sources of beam-induced background using the Doppler shift of emitted gamma rays is presented. The feasibility of radiative-capture studies at energies of astrophysical interest is discussed for several experimental scenarios. © Società Italiana di Fisica/Springer-Verlag 2005.

  • 72.
    Benavides, Vicente
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Chernogorova, Olga
    A.A. Baikov Institute of Metallurgy and Materials Science (IMET), Moscow, Baikov Institute of Metallurgy and Materials Science (IMET), Russian Academy of Sciences.
    Drozdova, Ekaterina I.
    A.A. Baikov Institute of Metallurgy and Materials Science (IMET), Moscow.
    Ushakova, Iraida N.
    A.A. Baikov Institute of Metallurgy and Materials Science (IMET), Moscow.
    Soldatov, Alexander
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Raman and electron microscopy study of C60 collapse/transformation to a nanoclustered graphene-based disordered carbon phase at high pressure/temperature2015Inngår i: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 252, nr 11, s. 2626-2629Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Transformation of C60 polymers to a superelastic hard carbon (nanoclustered graphene phase (NGP)) occurring in metal matrix at 5 GPa in a temperature interval of 1000–1100 K was studied by optical, scanning electron microscopy (SEM), and Raman spectroscopy. Raman spectral scan across the sample surface allowed us to identify different stages of the structural transformation. The SEM and Raman spectroscopy data testify for the NGP appearance at the defects concentration sites in the parent fullerite structure. We propose that the buckyballs collapse/formation of the NGP is governed by nucleation and growth (diffusive) mechanism unlike earlier discussed in the literature possibility of the martensitic-type (displacive) character of this transformation.

  • 73.
    Benetti, Daniele
    et al.
    INRS Centre for Energy, Materials and Telecommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada..
    Cui, Daling
    INRS Centre for Energy, Materials and Telecommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada..
    Zhao, Haiguang
    INRS Centre for Energy, Materials and Telecommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada..
    Rosei, Federico
    INRS Centre for Energy, Materials and Telecommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada..
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Direct Measurement of Electronic Band Structure in Single Quantum Dots of Metal Chalcogenide Composites.2018Inngår i: Small (Weinheim an der Bergstrasse, Germany), ISSN 1613-6810, Vol. 14, nr 51, artikkel-id 1801668Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metal chalcogenide quantum dots (QDs) are among the most promising materials as light harvesters in all-inorganic systems for applications in solar cells and production of solar fuels. The electronic band structure of composite QDs formed by lead and cadmium chalcogenides directly grafted on highly oriented pyrolytic graphite surfaces through successive ionic layer absorption and reaction is investigated. Atomic force microscopy and Kelvin probe force microscopy (KPFM) are applied to investigate PbS, CdS, and PbS/CdS QD systems. The variation of the surface potential of individual QDs is measured, investigating the evolution of the electronic band structure as a function of QD size and composition. A shift of the Fermi level toward more negative values occurs when QD size is increased. The shift is more pronounced in CdS than in PbS, while the composite PbS/CdS exhibits an intermediate behavior. The calculated shift is in good agreement with the experiments. These results highlight the ability of KPFM to directly measure the electronic band structure in individual QDs of metal chalcogenide composites. This feature regulates charge dynamics in composite systems, thereby affecting device performance. This work provides valuable insights for applications in several fields, in which charge injection plays a major role.

  • 74.
    Benetti, Daniele
    et al.
    INRS Centre for Energy, Materials and Telecommunications.
    Dembele, Kadiatou Therese
    INRS Centre for Energy, Materials and Telecommunications.
    Benavides, Jaime
    Département de Génie Électrique, École de Technologie Supérieure, Montréal.
    Zhao, Haiguang
    INRS Centre for Energy, Materials and Telecommunications, CNR-INO SENSOR Lab.
    Cloutier, Sylvain
    Département de Génie Électrique, École de Technologie Supérieure, Montréal.
    Concina, Isabella
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Rosei, Federico
    INRS Centre for Energy, Materials and Telecommunications, Institute for Fundamental and Frontier Science University of Electronic 15 Science and Technology of China, Center for Self-Assembled Chemical Structures, McGill University.
    Functionalized multi-wall carbon nanotubes/TiO2 composites as efficient photoanodes for dye sensitized solar cells2016Inngår i: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 4, nr 16, s. 3555-3562Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on the effects of incorporation of different concentrations of carboxyl group (COOH)-functionalized multi-wall carbon nanotubes (F-MWCNTs) into TiO2 active layers for dye-sensitized solar cells (DSSCs). Standard DSSCs with bare TiO2 exhibit a photo-conversion efficiency (PCE) of 6.05% and a short circuit current density (Jsc) of 13.3 mA cm−2. The presence of 2 wt% F-MWCNTs in the photoanodes increases the PCE up to 7.95% and Jsc up to 17.5 mA cm−2. The photoanodes were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. The electrochemical behaviour of the solar cells was investigated by electrochemical impedance spectroscopy (EIS). We attribute the improved performances to the combined effect of increased dye loading and reduced charge recombination (as clarified by dye loading and EIS measurements), due to the conformal coverage of F-MWCNTs, which allows fast and efficient charge collection in operating solar cells. These results can help in improving the PCE in DSSCs in an elegant and straightforward way, minimizing the need of additional steps (e.g. pre- and post-treatment with TiCl4) for photoanode preparation.

  • 75.
    Benetti, Daniele
    et al.
    INRS Centre for Energy, Materials and Telecommunications, Varennes, Québec, Canada.
    Jokar, Efat
    Department of Applied Chemistry, Institute of Molecular Science and Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu, Taiwan. Center for Emergent Functional Matter Science, National Chiao Tung University, Taiwan.
    Yu, Che-Hsun
    Department of Applied Chemistry, Institute of Molecular Science and Center for Emergent Functional Matter Science, National Chiao Tung University, Taiwan.
    Fathi, Amir
    Department of Applied Chemistry, Institute of Molecular Science and Center for Emergent Functional Matter Science, National Chiao Tung University, Taiwan.
    Zhao, Haiguang
    INRS Centre for Energy, Materials and Telecommunications, Varennes, Québec, Canada.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Wei-Guang Diau, Eric
    Department of Applied Chemistry, Institute of Molecular Science and Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu, Taiwan. Center for Emergent Functional Matter Science, National Chiao Tung University, Taiwan.
    Rosei, Federico
    INRS Centre for Energy, Materials and Telecommunications, Varennes, Québec, Canada. Institute of Fundamental and Frontier Science, University of Electronic Science and Technology of China, Chengdu, China.
    Hole-extraction and photostability enhancement in highly efficient inverted perovskite solar cells through carbon dot-based hybrid material2019Inngår i: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 62, s. 781-790Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report the effect of the integration of carbon dots (Cdots) in high-performance inverted planar-heterojunction (PHJ) perovskite solar cells (PSCs). We used Cdots to modify the hole-transport layer in planar PSC devices. By introducing Cdots on graphene oxide (GO) as hole-transporting layer, the efficiency of the PSC improved significantly from 14.7% in the case of bare GO to 16.2% of the best device with optimized Cdots content. When applying Cdots with an engineered absorption in the UV range as downshifting layer, the device performance was further improved, attaining a maximum PCE of 16.8% (+14%); the stability of the device was also enhanced of more than 20%. Kelvin probe force microscopy (KPFM) and cyclic voltammetry (CV) were employed to analyze the electronic band alignment at the interface between GO/Cdots and the perovskite film. Holes were extracted and transferred to the conductive substrate more efficiently in the presence of Cdots, thus delaying charge recombination. Photoluminescence (PL), transient PL decays and transient photovoltage (TPV) decays investigated the charge-transfer kinetics and proved the retardation of charge recombination. This work reveals an effective enhancement of the performance of planar PSCs by using Cdots/GO as hole transport material.

  • 76.
    Berezovsky, Vladimir
    et al.
    Department of Applied Mathematics and High-performance ComputingM.V.Lomonosov Northern (Arctic) Federal University, Arkhangelsk.
    Öberg, Sven
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Computational study of the CO adsorption and diffusion in zeolites: validating the Reed–Ehrlich model2018Inngår i: Adsorption, ISSN 0929-5607, E-ISSN 1572-8757, Vol. 24, nr 4, s. 403-413Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Molecular simulations have been employed to explore at the microscopic scale the adsorption of CO in zeolites (MFI, CHA and DDR). On the basis of classical force fields, grand canonical Monte Carlo simulations are performed to predict the adsorption properties (isotherms) of these types of zeolites up to high pressure. Subsequent careful analysis yields details the microscopic mechanism in play, along the whole adsorption process, together with a considering of the arrangements of CO in MFI at high pressure. This work also summarizes an approach which uses single component diffusion data in prediction of multicomponent diffusion.

  • 77.
    Berger, Malin
    Luleå tekniska universitet, Institutionen för system- och rymdteknik.
    Testing of micro-fluidic systems for Raman spectroscopic measurements on biological cells2018Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Pulmonary Artery Hypertension (PAH) is a condition that can affect people as a consequence of infections or diseases such as lung disease, high blood pressure or pneumonia. When afflicted by these diseases, low oxygen content in the lung tissue causes the pulmonary arterial soft muscle cells (PASMC) located in the walls of the pulmonary arteries to chronically swell up. As a result, the arteries are constantly narrowed. This can in many cases be fatal as the arteries become clogged and the heart is forced to pump more blood to the lungs, causing an enlargement of the right heart chamber which eventually may lead to heart failure. This irreversible swelling of the PASMC is the cause for PAH. To find a treatment for this incurable disease, the mechanisms of the vasoconstriction need to be investigated. 

    Spectroscopy is the study of the interactions between light and matter and is a tool that can be used to gain knowledge in the matter of the expansions of the PASMC. In particular, Raman spectroscopy that targets the inelastic interactions can be used since it registers dynamic changes of cells. 

    To simulate an oxygen deprived environment, a micro-fluidic system designed for use in cellular experiments has been developed. Tests of the prototypes showed strong Raman signals from the polymeric material of the system itself. These signals overshadowed the signals from the observed sample. The objective of the experiments presented in this report was to test whether the signals from the micro-fluidic system could be eliminated by adding spacing between the polymer and the sample. 

    The experiment was conducted by collecting data of samples from baker's yeast prepared in the micro-fluidic system at different z-distances. By this the optimal spacing between the polymer of the micro-fluidic system and the sample could be determined. This experiment concluded that the sample needed to be placed 1.54 mm further from the micro-fluidic system in order to test human lung tissue at 2 mW laser intensity.

  • 78.
    Bergqvist, Lars
    et al.
    KTH, Royal Institute of Technology, Department of Materials and Nano Physics.
    Taroni, Andrea
    Department of Physics and Astronomy, Uppsala University.
    Bergman, Anders
    Department of Physics and Astronomy, Uppsala University.
    Etz, Corina
    Department of Physics and Astronomy, Uppsala University.
    Eriksson, Olle
    Uppsala universitet, Department of Physics and Astronomy, Uppsala University.
    Atomistic spin dynamics of low-dimensional magnets2013Inngår i: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 87, artikkel-id 144401Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigate the magnetic properties of a range of low-dimensional ferromagnets using a combination of first-principles calculations and atomistic spin dynamics simulations. This approach allows us to evaluate the ground state and finite temperature properties of experimentally well characterized systems such as Co/Cu(111), Co/Cu(001), Fe/Cu(001) and Fe/W(110), for different thicknesses of the magnetic layer. We compare our calculated spin wave spectra with experimental data available in the literature, and find a good quantitative agreement. We also predict magnon spectra for systems for which no experimental data exist at the moment, and estimate the role of temperature effects

  • 79. Bergström, Lars
    et al.
    Fredriksson, Sverker
    Backward production on nuclei and the tube model1980Inngår i: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 21, nr 1, s. 305-307Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is shown that the recent data from Burke et al. on backward production in 200-GeV/c nA collisions are in good agreement with expectations from the collective tube model with tube fragmentation taken into account.

  • 80. Bergström, Lars
    et al.
    Fredriksson, Sverker
    Estimates of recoil nucleon spectra in high-energy hadron-nucleus collisions1977Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 68, nr 2, s. 177-179Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is shown that recent data on the recoil nucleon spectrum in 10.5 GeV/c pion-neon collisions are in excellent agreement with a parameter free estimate from the so called tube model for high-energy hadron-nucleus collisions. A simple independent collision model is also treated.

  • 81. Bergström, Lars
    et al.
    Fredriksson, Sverker
    Is the recently published counterproof of the tube model credible?1978Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 78, nr 2-3, s. 337-341Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is shown that recent data from pion and proton collision with emulsion nuclei at 200 GeV/c are in perfect agreement with expectations from the collective tube model. The opposite conclusion in publications by Azimov et al. came about because the authors ignored the important effects of target fragmentation.

  • 82. Bergström, Lars
    et al.
    Fredriksson, Sverker
    The deuteron in high-energy physics1980Inngår i: Reviews of Modern Physics, ISSN 0034-6861, E-ISSN 1539-0756, Vol. 51, nr 4, s. 675-697Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The deuterium nucleus plays an important role in several branches of high-energy physics. We review its present status as a neutron source, a relativistic bound state, a collective six-quark state and a double scatterer.

  • 83.
    Bergwall, Staffan
    Luleå tekniska universitet.
    Sveptunnelmikroskopet: ett nytt sätt att se in i atomernas värld1989Rapport (Annet vitenskapelig)
  • 84.
    Bergwall, Staffan
    Luleå tekniska universitet.
    Synchrotron radiation in soft X-ray and electron spectroscopy1990Rapport (Annet vitenskapelig)
  • 85. Beton, P.
    et al.
    Moriarty, P.
    Keeling, D.
    Dunsch, L.
    Georgi, P.
    Wang, Chun-Ru
    Greer, J.C.
    Larsson, Andreas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Smith, R.
    Godwin, P.
    Suter, D.
    Udovicic, L.
    Weidinger, A.
    Harneit, W.
    Waiblinger, M.
    Welland, M.
    Durkan, C.
    A study for the construction of a quantum information precessing device using doped fullerenes2000Konferansepaper (Fagfellevurdert)
  • 86.
    Betti, M.G
    et al.
    INFN Sezione di Roma, Roma, Italy; Sapienza Università di Roma, Roma, Italy.
    Strid, C.F
    Luleå tekniska universitet. Stockholm University, Stockholm, Sweden.
    Zurek, K.M
    Lawrence Berkeley National Laboratory, University of California, Berkeley, CA, USA; Department of Physics, University of California, Berkeley, CA, USA.
    A design for an electromagnetic filter for precision energy measurements at the tritium endpoint2019Inngår i: Progress in Particle and Nuclear Physics, ISSN 0146-6410, E-ISSN 1873-2224, Vol. 106, s. 120-131Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a detailed description of the electromagnetic filter for the PTOLEMY project to directly detect the Cosmic Neutrino Background (CNB). Starting with an initial estimate for the orbital magnetic moment, the higher-order drift process of E×B is configured to balance the gradient-B drift motion of the electron in such a way as to guide the trajectory into the standing voltage potential along the mid-plane of the filter. As a function of drift distance along the length of the filter, the filter zooms in with exponentially increasing precision on the transverse velocity component of the electron kinetic energy. This yields a linear dimension for the total filter length that is exceptionally compact compared to previous techniques for electromagnetic filtering. The parallel velocity component of the electron kinetic energy oscillates in an electrostatic harmonic trap as the electron drifts along the length of the filter. An analysis of the phase-space volume conservation validates the expected behavior of the filter from the adiabatic invariance of the orbital magnetic moment and energy conservation following Liouville's theorem for Hamiltonian systems.

  • 87.
    Bhandary, Sumanta
    et al.
    Uppsala universitet, Department of Physics and Astronomy, Uppsala University.
    Brena, Barbara
    Uppsala universitet, Department of Physics and Astronomy, Uppsala University.
    Panchmatia, P. M.
    School of Applied Sciences, University of Huddersfield, Queensgate.
    Brumboiu, Iulia
    Uppsala universitet, Department of Physics and Astronomy, Uppsala University.
    Bernien, M.
    Institut für Experimentalphysik, Freie Universität Berlin.
    Weis, Claudia
    Faculty of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen.
    Krumme, B.
    Faculty of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen.
    Etz, Corina
    Department of Physics and Astronomy, Uppsala University.
    Kuch, W.
    Institut für Experimentalphysik, Freie Universität Berlin.
    Wende, H.
    Faculty of Physics and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen.
    Eriksson, Olle
    Uppsala universitet, Department of Physics and Astronomy, Uppsala University.
    Sanyal, Biplab
    Uppsala universitet, Department of Physics and Astronomy, Uppsala University.
    Manipulation of spin state of iron porphyrin by chemisorption on magnetic substrates2013Inngår i: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 88, nr 2, artikkel-id 24401Artikkel i tidsskrift (Fagfellevurdert)
  • 88.
    Bhardwaj, Anshuman
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Sam, Lydia
    Institut für Kartographie, Technische Universität Dresden.
    Martin-Torres, Javier
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Zorzano Mier, Maria-Paz
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Fonseca, Ricardo
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Martian slope streaks as plausible indicators of transient water activity2017Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, nr 1, artikkel-id 7074Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Slope streaks have been frequently observed in the equatorial, low thermal inertia and dusty regions of Mars. The reason behind their formation remains unclear with proposed hypotheses for both dry and wet mechanisms. Here, we report an up-to-date distribution and morphometric investigation of Martian slope streaks. We find: (i) a remarkable coexistence of the slope streak distribution with the regions on Mars with high abundances of water-equivalent hydrogen, chlorine, and iron; (ii) favourable thermodynamic conditions for transient deliquescence and brine development in the slope streak regions; (iii) a significant concurrence of slope streak distribution with the regions of enhanced atmospheric water vapour concentration, thus suggestive of a present-day regolith-atmosphere water cycle; and (iv) terrain preferences and flow patterns supporting a wet mechanism for slope streaks. These results suggest a strong local regolith-atmosphere water coupling in the slope streak regions that leads to the formation of these fluidised features. Our conclusions can have profound astrobiological, habitability, environmental, and planetary protection implications

  • 89.
    Bhuiyan, Iftekhar Uddin
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Mouzon, Johanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Schröppel, Birgit
    Natural and Medical Sciences Institute (NMI), University of Tübingen.
    Kaech, Andres
    Center for Microscopy and Image Analysis, University of Zurich.
    Dobryden, Illia
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Forsmo, Seija P.E.
    LKAB, Research & Development, 983 81 Malmberget.
    Hedlund, Jonas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Microstructure of Bentonite in Iron Ore Green Pellets2014Inngår i: Microscopy and Microanalysis, ISSN 1431-9276, E-ISSN 1435-8115, Vol. 20, nr 1, s. 33-41Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Sodium-activated calcium bentonite is used as a binder in iron ore pellets and is known to increase strength of both wet and dry iron ore green pellets. In this article, the microstructure of bentonite in magnetite pellets is revealed for the first time using scanning electron microscopy. The microstructure of bentonite in wet and dry iron ore pellets, as well as in distilled water, was imaged by various imaging techniques (e.g., imaging at low voltage with monochromatic and decelerated beam or low loss backscattered electrons) and cryogenic methods (i.e., high pressure freezing and plunge freezing in liquid ethane). In wet iron ore green pellets, clay tactoids (stacks of parallel primary clay platelets) were very well dispersed and formed a voluminous network occupying the space available between mineral particles. When the pellet was dried, bentonite was drawn to the contact points between the particles and formed solid bridges, which impart strength to the solid compact.

  • 90.
    Bianchi, F
    et al.
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Careni, M
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Mangia, A
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Mattarozzi, M
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Musci, M
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Concina, Isabella
    INFM-CNR SENSOR Lab. and Physics and Chemistry Department.
    Gobbi, Emanuela
    CNR IDASC SENSOR Lab, University of Brescia.
    Characterisation of the volatile profile of orange juice contaminated with Alicyclobacillus acidoterrestris2010Inngår i: Food Chemistry, ISSN 0308-8146, E-ISSN 1873-7072, Vol. 123, nr 3, s. 653-658Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A rapid and reliable analytical method, based on the characterisation of the volatile profile by dynamic headspace extraction followed by gas chromatography mass-spectrometry, was developed in order to early detect Alicyclobacillus acidoterrestris spoilage in orange juice. Gas chromatographic peak areas were submitted to multivariate statistical analysis (principal component and linear discriminant analysis) in order to visualise clusters within samples and to detect the volatile compounds able to differentiate contaminated from not-contaminated samples. Significant differences in the volatile profile of the analysed samples were found, assessing the reliability of the proposed method to detect the A. acidoterrestris contamination in orange juice.Neither guaiacol nor 2,6-dibromophenol, usually regarded as A. acidoterrestris contamination markers, were detected in the analysed samples.

  • 91.
    Bianchi, F
    et al.
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Careri, M
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Mangia, A
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Mattarozzi, M
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Musci, M
    Univ Studi Parma, Dipartimento Chim Gen & Inorgan,.
    Concina, Isabella
    University of Brescia, CNR-INFM SENSOR Laboratory.
    Falasconi, Matteo
    CNR IDASC SENSOR Lab, University of Brescia.
    Gobbi, Emanuela
    Univ Udine.
    Pardo, Matteo
    CNR-IDASC SENSOR Lab and Dipartimento di Chimica e Fisica per l'Ingegneria e per i Materiali, University of Brescia.
    Sberveglieri, Giorgio
    SENSOR Lab, Department of Information Engineering, University of Brescia.
    Differentiation of the volatile profile of microbiologically contaminated canned tomatoes by dynamic headspace extraction followed by gas chromatography-mass spectrometry analysis2009Inngår i: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 77, nr 3, s. 962-970Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aromatic profile of microbiologically contaminated canned tomatoes was analyzed by the dynamic headspace extraction technique coupled with gas chromatography-mass spectrometry. Canned tomatoes contaminated with Escherichia coli, Saccharomyces cerevisiae and Aspergillus carbonarius were analyzed after 2 and 7 days. About 100 volatiles were detected, among which alcohols, aldehydes and ketones were the most abundant compounds. Gas chromatographic peak areas were used for statistical purposes. First, principal component analysis was carried out in order to visualize data trends and clusters. Then, linear discriminant analysis was performed in order to detect the set of volatile compounds ables to differentiate groups of analyzed samples. Five volatile compounds, i.e. ethanol, beta-myrcene,o-methyl styrene, 6-methyl-5-hepten-2-ol and 1-octanol, were found to be able to better discriminate between uncontaminated and contaminated samples. Prediction ability of the calculated model was estimated to be 100% by the "leave-one-out" cross-validation. An electronic nose device was then used to analyze the same contaminated and not contaminated canned tomato samples. Preliminary results were compared with those obtained by dynamic headspace gas chromatography-mass spectrometry, showing a good agreement.

  • 92.
    Bianchi, S.
    et al.
    CNR IDASC SENSOR Lab.
    Comini, E.
    CNR IDASC SENSOR Lab.
    Ferroni, M.
    CNR IDASC SENSOR Lab.
    Faglia, G.
    CNR IDASC SENSOR Lab.
    Vomiero, Alberto
    University of Brescia, CNR-INFM SENSOR Laboratory.
    Sberveglieri, G.
    CNR IDASC SENSOR Lab.
    Indium oxide quasi-monodimensional low temperature gas sensor2006Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 118, nr 1-2, s. 204-207Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have investigated the sensing properties of indium oxide nanostructures and tailored the deposition conditions in order to obtain nano-wires of indium oxide. We have comparatively tested the gas sensing properties of nano-wires with micrometric or even nanometric size. The micro-wires feature interesting gas sensitivity at room temperature, particularly in the case of nitrogen dioxide detection. The sensing performance is improved as the lateral dimension of the wire decreases. © 2006 Elsevier B.V. All rights reserved.

  • 93.
    Blaschke, D.
    et al.
    Gesellschaft für Schwerionenforschung mbH (GSI).
    Fredriksson, Sverker
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Grigorian, H.
    Institut für Physik, Universität Rostock.
    Öztas, A.M.
    Department of Physics, Hacettepe University.
    Sandin, Fredrik
    The Phase diagram of three-flavor quark matter under compact star constraints2005Inngår i: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 72, nr 6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The phase diagram of three-flavor quark matter under compact star constraints is investigated within a Nambu-Jona-Lasinio model. Global color and electric charge neutrality is imposed for beta-equilibrated superconducting quark matter. The constituent quark masses and the diquark condensates are determined self-consistently in the plane of temperature and quark chemical potential. Both strong and intermediate diquark coupling strengths are considered. We show that in both cases, gapless superconducting phases do not occur at temperatures relevant for compact star evolution, i.e., below T~50 MeV. The stability and structure of isothermal quark star configurations are evaluated. For intermediate coupling, quark stars are composed of a mixed phase of normal (NQ) and two-flavor superconducting (2SC) quark matter up to a maximum mass of 1.21 M[sun]. At higher central densities, a phase transition to the three-flavor color flavor locked (CFL) phase occurs and the configurations become unstable. For the strong diquark coupling we find stable stars in the 2SC phase, with masses up to 1.33 M[sun]. A second family of more compact configurations (twins) with a CFL quark matter core and a 2SC shell is also found to be stable. The twins have masses in the range 1.30...1.33 M[sun]. We consider also hot isothermal configurations at temperature T=40 MeV. When the hot maximum mass configuration cools down, due to emission of photons and neutrinos, a mass defect of 0.1 M[sun] occurs and two final state configurations are possible

  • 94.
    Blaschke, David
    et al.
    Rostock University.
    Fredriksson, Sverker
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Grigorian, H.
    Rostock University.
    Oztas, A.M.
    Hacettepe University, Ankara.
    Diquark condensation effects on hot quark star configurations2004Inngår i: Nuclear Physics A, ISSN 0375-9474, E-ISSN 1873-1554, Vol. 736, nr 1-2, s. 203-219Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The equation of state for quark matter is derived for a nonlocal, chiral quark model within the mean field approximation. We investigate the effects of a variation of the formfactors of the interaction on the phase diagram of quark matter. Special emphasis is on the occurrence of a diquark condensate which signals a phase transition to color superconductivity and its effects on the equation of state under the condition of β-equilibrium and charge neutrality. We calculate the quark star configurations by solving the Tolman-Oppenheimer-Volkoff equations and obtain for the transition from a hot, normal quark matter core of a protoneutron star to a cool diquark condensed one a release of binding energy of the order of ΔMc2˜1053 erg. We find that this energy could not serve as an engine for explosive phenomena since the phase transition is not first order. Contrary to naive expectations the mass defect increases when for a given temperature we neglect the possibility of diquark condensation.

  • 95.
    Blaschke, David
    et al.
    Rostock University.
    Fredriksson, Sverker
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Oztas, Ahmet Mecit
    Hacettepe University, Ankara.
    Diquark properties and the TOV equations2001Inngår i: Proceedings of the Conference on Compact Stars in the QCD Phase Diagram (CSQCD), Copenhagen, Denmark, August 15 - 18, 2001 / [ed] Rachid Ouyed ..., 2001, s. 167-173Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present various results from including diquark properties and the gap equations into the TOV equations for compact quark objects. One such property is the diquark form factor, which has a strong influence on various quantities. We discuss the consequences for quark stars.

  • 96.
    Blaschke, David
    et al.
    University of Wroclaw.
    Klahn, Thomas
    Argonne National Laboratory, Argonne, IL.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Equation of state at high densities and modern compact star observations2008Inngår i: Journal of Physics G: Nuclear and Particle Physics, ISSN 0954-3899, E-ISSN 1361-6471, Vol. 35, nr 1, s. 014051-6Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recently, observations of compact stars have provided new data of high accuracy which put strong constraints on the high-density behaviour of the equation of state of strongly interacting matter otherwise not accessible in terrestrial laboratories. The evidence for neutron stars with high mass (M = 2.1 +/- 0.2 M-circle dot for PSR J0751 + 1807) and large radii (R > 12 km for RX J1856-3754) rules out soft equations of state and has provoked a debate whether the occurrence of quark matter in compact stars can be excluded as well. In this contribution, it is shown that modern quantum field theoretical approaches to quark matter including colour superconductivity, and a vector meanfield allow a microscopic description of hybrid stars which fulfil the new, strong constraints. The deconfinement transition in the resulting stiff hybrid equation of state is weakly first order so that its signals have to be expected due to specific changes in transport properties governing the rotational and cooling evolution caused by the colour superconductivity of quark matter. A similar conclusion holds for the investigation of quark deconfinement in future generations of nucleus-nucleus collision experiments at low temperatures and high baryon densities such as CBM @ FAIR.

  • 97.
    Blaschke, David
    et al.
    University of Wroclaw.
    Klähn, Thomas
    Argonne National Laboratory, Argonne, IL.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Color superconducting quark matter in compact stars2008Inngår i: Exotic States of Nuclear Matter: Proceedings of the International Symposium EXOCT07, Catania University, Italy, 11 - 15 June 2007 / [ed] Umberto Lombardo; Marcello Baldo; Fiorella Burgio; Hans-Josef Schulze, Hackensack, NJ: World Scientific and Engineering Academy and Society, 2008, s. 256-263Konferansepaper (Fagfellevurdert)
  • 98.
    Blaschke, David
    et al.
    Instytut Fizyki Teoretycznej, Uniwersytet Wrocławski.
    Sandin, Fredrik
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Klähn, Thomas
    Argonne National Laboratory, Argonne, IL.
    Berdermann, Jens
    DESY Zeuthen, Berlin.
    Single-flavor CSL phase in compact stars2008Inngår i: Hadronic physics: Joint Meeting Heidelberg-Liège-Paris-Wroclaw, HLPW 2008, Spa, Belgium, 6 - 8 March 2008 / [ed] Joseph Cugnon; Jean-Philippe Lansberg, Melville, NY: American Institute of Physics (AIP), 2008, s. 183-192Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We suggest a scenario where the three light quark flavors are sequentially deconfined under increasing pressure in cold asymmetric nuclear matter as, e.g., in neutron stars. The basis for our analysis is a chiral quark matter model of Nambu-Jona-Lasinio (NJL) type with diquark pairing in the spin-1 single flavor (CSL), spin-0 two flavor (2SC) and three flavor (CFL) channels. We find that nucleon dissociation sets in at about the saturation density, n0, when the down-quark Fermi sea is populated (d-quark dripline) due to the flavor asymmetry induced by β-equilibrium and charge neutrality. At about 3n0 u-quarks appear and a two-flavor color superconducting (2SC) phase is formed. The s-quark Fermi sea is populated only at still higher baryon density, when the quark chemical potential is of the order of the dynamically generated strange quark mass. We construct two different hybrid equations of state (EoS) using the Dirac-Brueckner Hartree-Fock (DBHF) approach and the EoS by Shen et al. in the nuclear matter sector. The corresponding hybrid star sequences have maximum masses of, respectively, 2.1 and 2.0 M⊙. Two- and three-flavor quark-matter phases exist only in gravitationally unstable hybrid star solutions in the DBHF case, while the Shen-based EoS produce stable configurations with a 2SC phase component in the core of massive stars. Nucleon dissociation due to d-quark drip at the crust-core boundary fulfills basic criteria for a deep crustal heating process which is required to explain superbusts as well as cooling of X-ray transients.

  • 99.
    Borgani, Riccardo
    et al.
    Nanostructure Physics, KTH Royal Institute of Technology, Stockholm, Sweden.
    Gilzad Kohan, Mojtaba
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Haviland, David B.
    Nanostructure Physics, KTH Royal Institute of Technology, Stockholm, Sweden.
    Fast Multifrequency Measurement of Nonlinear Conductance2019Inngår i: Physical Review Applied, E-ISSN 2331-7019, Vol. 11, nr 4, artikkel-id 044062Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We describe a phase-coherent multifrequency lock-in measurement technique that uses the inverse Fourier transform to reconstruct the nonlinear current-voltage characteristic of a nanoscale junction. The method provides separation of the galvanic and displacement currents in the junction and easy cancellation of the parasitic displacement current from the measurement leads. These two features allow us to overcome traditional limitations imposed by the low conductance of the junction and the high capacitance of the leads, thus providing an increase in measurement speed of several orders of magnitude. We demonstrate the method in the context of conductive atomic force microscopy, acquiring current-voltage characteristics at every pixel while scanning at standard imaging speed.

  • 100.
    Bortoluzzi, Marco
    et al.
    Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia.
    Castro, Jesús
    Departamento de Química Inorgánica, Universidade de Vigo, Facultade de Química, Edificio de Ciencias Experimentais.
    Enrichi, Francesco
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Consorzio Interuniversitario Reattività Chimica e Catalisi (CIRCC) .
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Busato, Marta
    Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia.
    Huang, Weizhe
    Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari Venezia.
    Green-emitting manganese (II) complexes with phosphoramide and phenylphosphonic diamide ligands2018Inngår i: Inorganic Chemistry Communications, ISSN 1387-7003, E-ISSN 1879-0259, Vol. 92, s. 145-150Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tetrahedral manganese(II) complexes having formulae [MnX2{O = PR(NMe2)2}2] (X = Br, I; R = NMe2, Ph) were isolated and characterized, and in the case of [MnBr2{O = PPh(NMe2)2}2] the structure was ascertained by means of single crystal X-ray diffraction. All the complexes showed intense green emission assigned to the Mn(II) 4T1(4G) → 6A1(6S) transition upon excitation with UV light, with photoluminescence lifetimes in the range 100–1000 μs. Bromo-complexes maintain their luminescence features once dispersed in polycaprolactone matrix.

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