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  • 251.
    Fedorenko, Svetlana V.
    et al.
    A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of Russian Academy of Sciences.
    Jilkin, Michail E.
    Kazan (Volga Region) Federal University.
    Gryaznova, Tatyana V.
    A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of Russian Academy of Sciences.
    Iurko, Elizaveta O.
    A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of Russian Academy of Sciences.
    Bochkova, Olga D.
    A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of Russian Academy of Sciences.
    Mukhametshina, Alsu R.
    A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of Russian Academy of Sciences.
    Nizameev, Irek R.
    A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of Russian Academy of Sciences.
    Kholin, Kirill V.
    A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of Russian Academy of Sciences.
    Mazzaro, Raffaello
    CNR-IMM, Bologna Section.
    Morandi, Vittorio
    CNR-IMM, Bologna Section.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Mustafina, Asiya R.
    A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of Russian Academy of Sciences.
    Budnikova, Yulia H.
    A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of Russian Academy of Sciences.
    Silica Nanospheres Coated by Ultrasmall Ag0 Nanoparticles for Oxidative Catalytic Application2017Inngår i: Colloid and Interface Science Communications, ISSN 2215-0382, Vol. 21, s. 1-5Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present work introduces optimal modifiсation of core-shell composite nanomaterial, where small (2–8 nm) Ag0 nanoparticles are deposited onto large (about 140 nm) silica spheres for application in oxidative catalysis. The size of Ag0 and density of its deposition onto silica spheres was modified by the post treatment of initially deposited Ag0 (about 30 nm) by hydrogen peroxide in specific conditions. The comparison of catalytic effect of the post-treated and initial SN-Ag0 in electrochemical phosphonation of benzo(thia)oxazoles by diethyl phosphite in oxidative conditions revealed the difference between the composite nanoparticles. In particular, the post-treated SNs-Ag0 nanoparticles exhibit efficient catalytic effect in oxidative conditions resulting in facile and green method for synthesis of phosphonated benzooxa(thia)zoles, while no catalytic effect is observed under the use of larger Ag0 nanoparticles deposited onto silica spheres. The use of Ag0-based nanomaterial in oxidative catalysis had been never demonstrated before

  • 252.
    Fehér, Klaudia
    et al.
    Department of Organic Chemistry University of Pannonia, Institute of Chemistry Egyetem, Veszprém, Hungary.
    Nagy, Eniko
    Department of Organic Chemistry University of Pannonia, Institute of Chemistry Egyetem, Veszprém, Hungary.
    Szabo, Peter
    Department of Analytical Chemistry University of Pannonia, Institute of Chemistry Egyetem, Veszprém, Hungary.
    Juzsakova, Tatjana
    University of Pannonia, Institute of Environmental Engineering Egyetem, Veszprém Hungary.
    Srankó, David
    Department of Surface Chemistry and Catalysis Hungarian Academy of Sciences, Centre for Energy Research, Budapest, Hungary.
    Gömöry, Ágnes
    Research Centre for Natural Sciences Hungarian Academy of Sciences, Budapest, Hungary.
    Kollár, Lazslo
    Department of Inorganic Chemistry and MTA-PTE Research Group for Selective Chemical Syntheses University of Pécs, Pécs, Hungary.
    Skoda-Földes, Rita
    Department of Organic Chemistry University of Pannonia, Institute of Chemistry Egyetem, Veszprém, Hungary.
    Heterogeneous azide–alkyne cycloaddition in the presence of a copper catalyst supported on an ionic liquid polymer/silica hybrid material2018Inngår i: Applied organometallic chemistry, ISSN 0268-2605, E-ISSN 1099-0739, Vol. 32, nr 6, artikkel-id e4343Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Heterogeneous copper catalysts were prepared by the deposition of CuI on a hybrid material consisting of silica and a polymer with imidazolium moieties. The solid materials were characterised using solid‐phase NMR, Fourier transform infrared, Raman and X‐ray photoelectron spectroscopies and Brunauer–Emmett–Teller measurements. The formation of copper–carbene complexes was proved from Raman spectra and the results were supported by density functional theory calculations. The catalyst could be recycled efficiently with low loss of copper. Metal leaching was proved to be facilitated by the use of conditions typical for a homogeneous system (the presence of a polar solvent or the addition of a tertiary amine). Besides simple model reactions, the best catalyst was found to be suitable for the synthesis of triazoles of more elaborate structure, such as ferrocene or steroid derivatives.

  • 253.
    Fernández, C. De Julián
    et al.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Manera, M. G.
    CNR-IMM Sezione di Bologna.
    Spadavecchia, J.
    CNR-IMM Sezione di Bologna.
    Maggioni, G.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Quaranta, A.
    Laboratori Nazionali di Legnaro.
    Mattei, G.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Bazzan, M.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Cattaruzza, E.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Bonafini, M.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Negro, E.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Vomiero, Alberto
    Dipartimento di Fisica, Università di Padova.
    Carturan, S.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Scian, C.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Mea, G. Della
    Laboratori Nazionali di Legnaro.
    Rella, R.
    CNR-IMM Sezione di Bologna.
    Vasanelli, L.
    CNR-IMM Sezione di Bologna.
    Mazzoldi, P.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Study of the gas optical sensing properties of Au-polyimide nanocomposite films prepared by ion implantation2005Inngår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 111-112, nr SUPPL., s. 225-229Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Au-polyimide nanocomposites have been synthesized by implanting Au + ions in pyromellitic dianhydride-4,4′ oxydianiline polyimide films prepared by glow discharge vapor deposition polymerisation (GDVDP). A structural and optical characterization shows that Au clusters grow only implanting 5 × 1016 Au+/cm2. This sample class shows interesting dynamic optical absorption sensing responses towards methanol and ethanol vapors in the spectral range corresponding to the surface plasmon resonance (SPR) peak of the gold nanoparticles. Traditional surface plasmon resonance measurements performed onto virgin polyimide thin films in controlled atmosphere show a sensing activity due to a variation of the film thickness and of the real part of refractive index. The comparison of the results obtained onto virgin films and implanted ones suggests that the sensing mechanisms can be attributed both to the modification of polymer optical properties and to the chemical activity of gold nanoparticles. © 2005 Elsevier B.V. All rights reserved.

  • 254.
    Fiorini, M.
    et al.
    Ferrara University, INFN.
    Dalpiaz, P.
    Ferrara University, INFN.
    Guidi, V.
    Ferrara University, INFN.
    Assmann, R.
    CERN.
    Efthymiopoulos, I.
    CERN.
    Gatignon, L.
    CERN.
    Scandale, W.
    CERN.
    Taratin, A.
    JINR Dubna.
    Chesnokov, Y.
    IHEP Protvino.
    Ivanov, Y.
    PNPI Gatchina.
    Vomiero, Alberto
    INFN Laboratori Nazionali di Legnaro.
    Biino, C.
    INFN Sezione di Ferrara.
    Ambrosi, G.
    INFN Sezione di Ferrara.
    Santacesaria, R.
    INFN Sezione di Ferrara.
    Experimental study of crystal channeling at CERN-SPS for beam-HALO cleaning2006Inngår i: EPAC 2006: 10th European Particle Accelerator Conference EPAC 2006 ; a Europhysics conference ; Edinburgh, Scotland, International Conference Centre (EICC), 26 - 30 June 2006, Edinburgh: European Physical Society Accelerator Group (EPS-AG) , 2006, s. 1538-1540Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An efficient and robust collimation system is mandatory for any superconducting hadron collider, in particular for the LHC, which will store a beam of unprecedented high intensity and energy. The usage of highly efficient and short primary bent-crystal collimators might be a possibility for reaching nominal and ultimate LHC intensity. Over the last years, groups in Italy (Ferrara) and Russia (St. Petersburg) have developed crystal production methods, that considerably improve the crystal quality. These developments led, in turn, to a surprising increase in the channeling efficiency and to the recent observation of the "volume reflection" mechanism. The aim of the proposed experiment is the setup of a beam test facility, directing primary protons from the SPS onto a bent silicon crystal, and the quantitative study of single-pass efficiency for all involved processes. Final goal will be the extrapolation of important information on the feasibility of a crystal collimator for halo cleaning in the LHC. The experiment will be performed in the H8 beamline at the CERN SPS where a beam with very small divergence can be provided thus representing a unique facility for tests and characterization of crystals to be used for particle channeling studies.

  • 255.
    Fletcher, Leigh N.
    et al.
    Department of Physics and Astronomy, University of Leicester.
    Gustafsson, Magnus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Orton, Glenn S.
    Jet Propulsion Laboratory, California Institute of Technology.
    Hydrogen Dimers in Giant-planet Infrared Spectra2018Inngår i: Astrophysical Journal Supplement Series, ISSN 0067-0049, E-ISSN 1538-4365, Vol. 235, nr 1, artikkel-id 24Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Despite being one of the weakest dimers in nature, low-spectral-resolution Voyager/IRIS observations revealed the presence of (H2)2 dimers on Jupiter and Saturn in the 1980s. However, the collision-induced H2-H2 opacity databases widely used in planetary science have thus far only included free-to-free transitions and have neglected the contributions of dimers. Dimer spectra have both fine-scale structure near the S(0) and S(1) quadrupole lines (354 and 587 cm-1, respectively), and broad continuum absorption contributions up to ±50 cm-1 from the line centers. We develop a new ab initio model for the free-to-bound, bound-to-free, and bound-to-bound transitions of the hydrogen dimer for a range of temperatures (40-400 K) and para-hydrogen fractions (0.25-1.0). The model is validated against low-temperature laboratory experiments, and used to simulate the spectra of the giant planets. The new collision-induced opacity database permits high-resolution (0.5-1.0 cm-1) spectral modeling of dimer spectra near S(0) and S(1) in both Cassini Composite Infrared Spectrometer observations of Jupiter and Saturn, and in Spitzer Infrared Spectrometer (IRS) observations of Uranus and Neptune for the first time. Furthermore, the model reproduces the dimer signatures observed in Voyager/IRIS data near S(0) on Jupiter and Saturn, and generally lowers the amount of para-H2 (and the extent of disequilibrium) required to reproduce IRIS observations.

  • 256.
    Fomekong, Roussin Lontio
    et al.
    Department of High-Temperature and Functional Coatings, Institute of Materials Research, German Aerospace Center, Cologne, Germany.
    You, Shujie
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Enrichi, Francesco
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice, Italy.
    Vomiero, Alberto
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. Department of Molecular Sciences and Nanosystems, Ca’ Foscari University of Venice, Italy.
    Saruhan, Bilge
    Department of High-Temperature and Functional Coatings, Institute of Materials Research, German Aerospace Center, Cologne, Germany.
    Impact of Oxalate Ligand in Co-Precipitation Route on Morphological Properties and Phase Constitution of Undoped and Rh-Doped BaTiO3 Nanoparticles2019Inngår i: Nanomaterials, E-ISSN 2079-4991, Vol. 9, nr 12, artikkel-id 1697Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In order to design and tailor materials for a specific application like gas sensors, the synthesis route is of great importance. Undoped and rhodium-doped barium titanate powders were successfully synthesized by two routes; oxalate route and classic route (a modified conventional route where solid-state reactions and thermal evaporation induced precipitation takes place). Both powders were calcined at different temperatures. X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX) and Brunauer-Emmet-Teller (BET) analyses are employed to identify the phases and polymorphs, to determine the morphology, the chemical composition and the specific surface area of the synthesized materials, respectively. The so-called oxalate route yields pure BaTiO3 phase for undoped samples at 700 °C and 900 °C (containing both cubic and tetragonal structures), while the classic route-synthesized powder contains additional phases such as BaCO3, TiO2 and BaTi2O5. Samples of both synthesis routes prepared by the addition of Rh contain no metallic or oxide phase of rhodium. Instead, it was observed that Ti was substituted by Rh at temperatures 700 °C and 900 °C and there was some change in the composition of BaTiO3 polymorph (increase of tetragonal structure). Heat-treatments above these temperatures show that rhodium saturates out of the perovskite lattice at 1000 °C, yielding other secondary phases such as Ba3RhTi2O9 behind. Well-defined and less agglomerated spherical nanoparticles are obtained by the oxalic route, while the classic route yields particles with an undefined morphology forming very large block-like agglomerates. The surface area of the synthesized materials is higher with the oxalate route than with the classic route (4 times at 900 °C). The presence of the oxalate ligand with its steric hindrance that promotes the uniform distribution and the homogeneity of reactants could be responsible for the great difference observed between the powders prepared by two preparation routes.

  • 257.
    Formicola, A.
    et al.
    Institut Für Experimentalphysik III.
    Imbriani, G.
    Osservatorio Astronomico di Collurania, Teramo.
    Costantini, H.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Angulo, C.
    Centre de Recherches du Cyclotron, Universit¶e Catholique de Louvain, Louvain-la-Neuve.
    Bemmerer, D.
    Institut für Atomare Physik und Fachdidaktik, Technische Universität Berlin.
    Bonetti, R.
    Istituto di Fisica Generale Applicata.
    Broggini, C.
    INFN.
    Corvisiero, P.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Cruz, J.
    Centro de Fısica Nuclear da Universidade de Lisboa.
    Descouvemont, P.
    Physique Nucléaire Théorique et Physique Mathématique, Université Libre de Bruxelles.
    Fülöp, Z.
    Institute of Nuclear Research (ATOMKI), Debrecen.
    Gervino, G.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Guglielmetti, A.
    Istituto di Fisica Generale Applicata.
    Gustavino, C.
    INFN.
    Gyürky, G.
    Institute of Nuclear Research (ATOMKI), Debrecen.
    Jesus, A. P.
    Centro de Fısica Nuclear da Universidade de Lisboa.
    Junker, M.
    INFN.
    Lemut, A.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Menegazzo, R.
    INFN.
    Prati, P.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Roca, V.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Rolfs, C.
    Institut Für Experimentalphysik III.
    Romano, M.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Alvarez, C. Rossi
    INFN.
    Schümann, F.
    Institut Für Experimentalphysik III.
    Vomiero, Alberto
    Dipartimento di Fisica, Università di Padova.
    Zavatarelli, S.
    Dipartimento di Fisica Sperimentale, Università di Torino.
    Astrophysical S-factor of 14N(p,γ)15O2004Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 591, nr 1-2, s. 61-68Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We report on a new measurement of the 14N(p,γ) 15O capture cross section at Ep=140 to 400 keV using the 400 kV LUNA accelerator facility at the Laboratori Nazionali del Gran Sasso (LNGS). The uncertainties have been reduced with respect to previous measurements and their analysis. We have analyzed the data using the R-matrix method and we find that the ground state transition accounts for about 15% of the total S-factor. The main contribution to the S-factor is given by the transition to the 6.79 MeV state. We find a total S(0)=1.7±0.2 keVb, in agreement with recent extrapolations. The result has important consequences for the solar neutrino spectrum as well as for the age of globular clusters. © 2004 Elsevier B.V. All rights reserved.

  • 258.
    Fornasari, Luca
    et al.
    Dipartimento di Chimica “Giacomo Ciamician”, Università; di Bologna, Bologna, Italy.
    Mazzaro, Raffaello
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. CNR-IMM, Area della Ricerca di Bologna, Bologna, Italy.
    Boanini, Elisa
    Dipartimento di Chimica “Giacomo Ciamician”, Università; di Bologna, Bologna, Italy.
    d’Agostino, Simone
    Dipartimento di Chimica “Giacomo Ciamician”, Università; di Bologna, Bologna, Italy.
    Bergamini, Giacomo
    Dipartimento di Chimica “Giacomo Ciamician”, Università; di Bologna, Bologna, Italy.
    Grepioni, Fabrizia
    Dipartimento di Chimica “Giacomo Ciamician”, Università; di Bologna, Bologna, Italy.
    Braga, Dario
    Dipartimento di Chimica “Giacomo Ciamician”, Università; di Bologna, Bologna, Italy.
    Self-Assembly and Exfoliation of a Molecular Solid Based on Cooperative B-N and Hydrogen Bonds2018Inngår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 18, nr 12, s. 7259-7263Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herein we report that 4-pyridinylboronic acid (1) in the solid state self-assembles into tetrameric macrocycles via B-N bond formation. The tetramers are linked via O-H···O bonds resulting in a material that can be exfoliated via sonication to give thinner sheets as we demonstrate via Fourier transform infrared spectroscopy, transmission electron microscopy, selected area electron diffraction, and atomic force microscopy experiments. For comparison, the structure of the related compound 4-(pyridin-4-yl) phenylboronic acid (2) is also discussed

  • 259.
    Franz, Jan
    et al.
    University of Gothenburg.
    Gustafsson, Magnus
    Department of Chemistry, University of Gothenburg.
    Nyman, Gunnar
    Department of Chemistry and Molecular Biology, University of Gothenburg.
    Formation of carbon-monoxide by radiative association: a quantum-dynamical study2011Inngår i: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 414, nr 4, s. 3547-3550Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Rate coefficients for the formation of carbon monoxide (CO) by radiative association of carbon and oxygen atoms are computed using quantum dynamical simulations. At temperatures above 10 K CO radiative association is dominated by C(3P) and O(3P) approaching on the A1Π potential energy curve. The rate coefficient is estimated as k=A(T/300 K)αexp−β/T with A= 1.39 × 10−18 cm3 s−1, α=−0.016 and β= 92.2 for temperatures between 6 and 127.2 K, and A= 1.36 × 10−17 cm3 s−1, α= 0.41 and β= 340 for temperatures between 127.2 and 15 000 K. Furthermore we computed the rate coefficients for approaching on the X1Σ+ curve. For temperatures below 200 K it is between 0.7 × 10−22 and 4 × 10−22 cm3 s−1.

  • 260. Fredriksson, Sverker
    A phenomenological two-component picture of large transverse momentum production1976Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 63, nr 3, s. 321-323Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is suggested that large-pT hadrons can be classified into two categories with completely different properties according to whether they contain a leading quark or just sea quarks from the initial projectile-target system. From simple quark counting we get relations between hadron ratios at large pT, which are consistent with data.

  • 261.
    Fredriksson, Sverker
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    A (ud)-cious model of the proton1994Inngår i: Workshop on diquarks II: Villa Gualino, Torino, Italy, 2 - 4 November 1992 / [ed] Mauro Anselmino, Singapore: World Scientific and Engineering Academy and Society, 1994, s. 14-23Konferansepaper (Fagfellevurdert)
  • 262. Fredriksson, Sverker
    An estimate of the effect of nuclear Fermi motion on large transverse momentum inclusive spectra from high-energy proton-nucleus collisions1975Inngår i: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 94, nr 2, s. 337-343Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of nuclear Fermi motion on large-pT inclusive hadron spectra and particle ratios from high-energy proton-nucleus collisions is estimated within the scope of the parton model for proton-nucleon collisions and the box model for the nucleus. Considerable effects are found in some cases.

  • 263. Fredriksson, Sverker
    Clusters and tubes in multiparticle production from nuclear targets1980Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 45, nr 17, s. 1371-1374Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recent data on backward pion production in 0.8-4.89-GeV proton-nucleus collisions are analyzed within the scope of models where target nucleons react collectively. It is shown that the nuclear-size dependence in data is a sensitive probe of the effective target mass. The experimental results hint at a synthesis of the cluster ("fluctuon") model and the collective tube model.

  • 264.
    Fredriksson, Sverker
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Cosmic diquarks1998Inngår i: Workshop on Diquarks III: Villa Gualino, Torino, Italy, 28 -30 October 1996 / [ed] Mauro Anselino, Singapore: World Scientific Publishing Co Pte Ltd , 1998, s. 99-108Konferansepaper (Fagfellevurdert)
  • 265. Fredriksson, Sverker
    Demons at Celcius?1983Inngår i: Uppsala Workshop, Kungl. Tekniska Högskolan , 1983Konferansepaper (Fagfellevurdert)
  • 266. Fredriksson, Sverker
    Diquarks1987Inngår i: Proceedings: Dubna HEP Seminar 1986, Joint Institute for Nuclear Research , 1987, Vol. v.2:134Konferansepaper (Fagfellevurdert)
  • 267. Fredriksson, Sverker
    Diquarks1983Inngår i: Proceedings / [ed] Z. Ajduk, Warsaw Univ., Inst. Theor. Phys. , 1983Konferansepaper (Fagfellevurdert)
  • 268. Fredriksson, Sverker
    Electron-positron annihilation and related topics: an elementary introduction1975Rapport (Annet vitenskapelig)
  • 269. Fredriksson, Sverker
    Hello diquark, goodbye gluon !1984Inngår i: New Particle Production: Proceedings of the Hadronic session of the Nineteenth Rencontres de Moriond / [ed] J. Tran Thanh Van, Editions Frontieres , 1984, Vol. 2, s. 479-Konferansepaper (Fagfellevurdert)
  • 270. Fredriksson, Sverker
    Large-pT π0 Production in High-Energy πp Collisions1976Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 37, nr 21, s. 1373-1374Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is pointed out that the recently measured difference in pT spectrum between π±p→π0X and pp→π0X, with a large-pT π0, seems to be a consequence only of the smaller number of quarks per projectile in a pion beam.

  • 271. Fredriksson, Sverker
    Nuclear structure functions and the size of diquarks in nucleons1984Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 52, nr 9, s. 724-726Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is suggested that the observed difference between deep-inelastic structure functions from iron and deuterium targets comes about because two of the quarks in a nucleon are tightly bound in a diquark. It suffices for reproducing the data to assume that the diquark radius is enhanced by 10%-45% in a dense nucleus because of the disturbance from the surrounding nucleons. It is suggested how such a change of the diquark scale could be distinguished from the recently proposed change in the scale of the whole nucleon.

  • 272. Fredriksson, Sverker
    On large transverse momentum production in high-energy proton-nucleus collisions1976Inngår i: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 111, nr 1, s. 167-177Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Experimental data from inclusive production of large pT hadronsin high-energy proton-nucleus collisions are analysed with emphasis on the influence of the size of the target nucleus. It is found that data at pT≤3 GeV/c are consistent with the hypothesis that the incoming proton collides "simultaneously" with all the nucleons in its way, resulting in an effective collision energy larger than the one expected in a single proton-nucleon hit. At pT > 3 GeV/c, data are in conflict with such a simple model, a result we think is a consequence of the dominance of hard parton collisions at very large pT.

  • 273. Fredriksson, Sverker
    On the production of hadrons with large transverse momenta in high-energy proton-proton and proton-nucleus collisions1976Doktoravhandling, med artikler (Annet vitenskapelig)
  • 274. Fredriksson, Sverker
    Particle ratios in the central region of high-energy proton-proton collisions1975Inngår i: Nuclear Physics B, ISSN 0550-3213, E-ISSN 1873-1562, Vol. 84, nr 1, s. 234-252Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recent data from NAL on particle ratios ... large transverse momentum are analysed with emphasis on the surprising discovery that pions increase their dominance over heavier hadrons at increasing transverse momentum. It is argued that this is not a phase space or threshold effect but a dynamical feature that can be used to test theoretical models of multiparticle production. Most models of interest, such as for instance the parton, the hydrodynamical and the two-component model, may however be extended, in a simple-minded way, to kaon and antiproton production as to predict ratios of heavier to lighter hadrons to fall with increasing large transverse momentum.

  • 275. Fredriksson, Sverker
    Phenomenological relations between large-pT meson spectra1978Inngår i: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 18, nr 11, s. 4144-4151Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Recent data on the hadron ratios π+π-, K+π+, K-π-, and ηπ0 at large transverse momenta are shown to be consistent with predictions from a simple phenomenological two-component picture for large-pT production. The very-large-pT part of meson spectra is assumed to be dominated by particles that contain one of the incoming valence quarks, while small-and medium-pT mesons are built up mostly of quarks created in quark-antiquark pairs. Exceptions are K- and φ spectra, where for obvious reasons the very-large-pT component is missing. Simple relations between π, K, and η spectra are found. Predictions for the large-pT spectrum of φ mesons are presented.

  • 276.
    Fredriksson, Sverker
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Preon prophecies by the standard model2003Inngår i: Beyond the desert 2003: proceedings of the Fourth Tegernsee International Conference on Particle Physics Beyond the Standard Model, Beyond 2003, Castle Ringberg, Tegernsee, Germany, 9 - 14 June 2003 / [ed] Hans Volker Klapdor-Kleingrothaus, Berlin: Encyclopedia of Global Archaeology/Springer Verlag, 2003, s. 211-223Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Standard Model of quarks and leptons is, at first sight, nothing but a set of ad hoc rules, with no connections, and no clues to their true background. At a closer look, however, there are many inherent prophecies that point in the same direction: Compositeness in terms of three stable preons.

  • 277. Fredriksson, Sverker
    Recent results from the tube model for high-energy collisions with nuclei1978Inngår i: Proceedings of the topical meeting on recent developments in high-energy physics, Campione d'Italia, 3-7 October 1977 / [ed] Gianpaolo Bellini, Bologna: Compositor , 1978Konferansepaper (Fagfellevurdert)
  • 278. Fredriksson, Sverker
    The collective tube model and how to disprove it1979Inngår i: First workshop on ultra-relativistic nuclear collisions: [LBL, May 21-24, 1979], Berkeley, Calif: Lawrence Berkeley National Laboratory , 1979Konferansepaper (Fagfellevurdert)
  • 279. Fredriksson, Sverker
    The Emc effect as a diquark phenomenon1983Rapport (Annet vitenskapelig)
  • 280.
    Fredriksson, Sverker
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    The Stockholm diquark model1989Inngår i: Workshop on diquarks / [ed] Mauro Anselmino; Enrico Predazzi, Singapore: World Scientific and Engineering Academy and Society, 1989, s. 22-57Konferansepaper (Fagfellevurdert)
  • 281. Fredriksson, Sverker
    Vad har kvarkarna för sig i atomkärnan?1985Annet (Annet (populærvitenskap, debatt, mm))
  • 282. Fredriksson, Sverker
    Vakuum: mycket väsen för ingenting1985Annet (Annet (populærvitenskap, debatt, mm))
  • 283. Fredriksson, Sverker
    et al.
    Ekelin, Svante
    New ideas on the proton-neutron differences in deep inelastic structure functions1985Inngår i: Physics Letters B, ISSN 0370-2693, E-ISSN 1873-2445, Vol. 162, nr 4-6, s. 373-378Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is shown how future data from deep inelastic scattering of charged leptons on protons and neutrons can be used to discriminate between the two main possible scale-breaking QCD effects - perturbative gluon processes and non-perturbative diquark formation. Current data from the Stanford Linear Accelerator Center and from CERN on the structure function combinations Fp2-Fn2, Fn2/Fp2 and σL/σT are in line with both the Stockholm diquark model and perturbative QCD, considering the low statistics as well as the possibility of a substantial normalisation error between the two data sets. This calls for a new high-statistics experiment on a deuterium target before any definite conclusions can be made.

  • 284. Fredriksson, Sverker
    et al.
    Eliam, Gad
    Berlad, Gideon
    Bergström, Lars
    High-energy collisions with atomic nuclei: the experimental results1987Inngår i: Physics reports, ISSN 0370-1573, E-ISSN 1873-6270, Vol. 144, nr 4-5, s. 187-320Artikkel i tidsskrift (Fagfellevurdert)
  • 285. Fredriksson, Sverker
    et al.
    Enström, Daniel
    Hansson, Johan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Ekelin, Svante
    Kungliga tekniska högskolan, KTH.
    Nicolaidis, A.
    Is dark matter made up of massive quark objects?1999Inngår i: Dark matter in astrophysics and particle physics 1998: proceedings of the Second International Conference on Dark Matter in Astrophysics and Particle Physics / [ed] Hans Volker Klapdor-Kleingrothaus ; L. Baudis, Bristol: IOP Publishing Ltd , 1999, s. 651-658Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We suggest that dark matter is made up of massive quark objects that have survived from the Big Bang, representing the ground state of "baryonic'' matter. Hence, there was no overall phase transition of the original quark matter, but only a split-up into smaller objects. We speculate that normal hadronic matter comes about through enforced phase transitions when such objects merge or collide, which also gives rise to the cosmic gamma-ray bursts.

  • 286.
    Fredriksson, Sverker
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Hansson, Johan
    Ekelin, Svante
    Kungliga tekniska högskolan, KTH.
    A potential diquark in the proton1997Inngår i: Zeitschrift für Physik C Particles and Fields, ISSN 0170-9739, E-ISSN 1431-5858, Vol. 75, nr 1, s. 107-111Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A non-relativistic, QCD-based, potential quark model for the proton and the neutron inevitably predicts a spin-0 diquark structure with an rms radius of the order of 0.35rfm or smaller. We prove this by solving the (S wave) hamiltonian by De Rújula et al. with variational methods. It is essential to include all quark interactions and to use realistic test wave-functions. The protondelta mass difference, the magnetic moments and the nucleon charge radii can be reproduced only with wave functions that contain a mixture of quark-diquark and three-quark states. Approaches with just a quark-diquark component give incorrect magnetic moments, while those without diquarks lead to a too low proton-delta mass difference.

  • 287. Fredriksson, Sverker
    et al.
    Jändel, Magnus
    A new indication of diquarks in baryons1982Inngår i: Zeitschrift für Physik C Particles and Fields, ISSN 0170-9739, E-ISSN 1431-5858, Vol. 14, nr 1, s. 41-46Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In data from 100 GeV/c p d, 200 GeV/cpd and 200 GeV/cπ - d collisions there is evidence that the probability for a double-collisiondecreases slowly with increasing number of hadrons produced in the first projectile-nucleon collision. We argue that the presence of diquarks in baryons is the only plausible explanation of such an effect.

  • 288. Fredriksson, Sverker
    et al.
    Jändel, Magnus
    Demon deuteron: heavy or healthy?1982Rapport (Annet vitenskapelig)
  • 289. Fredriksson, Sverker
    et al.
    Jändel, Magnus
    Demon deuterons1981Inngår i: Berkeley 1981, Proceedings, High Energy Heavy Ion Study, 1981, s. 423-237Konferansepaper (Fagfellevurdert)
  • 290. Fredriksson, Sverker
    et al.
    Jändel, Magnus
    Demon deuterons: dead or alive?1982Rapport (Annet vitenskapelig)
  • 291. Fredriksson, Sverker
    et al.
    Jändel, Magnus
    Demon nuclei: a closer look!1982Rapport (Annet vitenskapelig)
  • 292. Fredriksson, Sverker
    et al.
    Jändel, Magnus
    Kicking around with the deuteron1981Inngår i: Dubna HEP Seminar 1981:0250, 1981Konferansepaper (Fagfellevurdert)
  • 293. Fredriksson, Sverker
    et al.
    Jändel, Magnus
    Probing the space-time structure of multiparticle production processes1981Inngår i: Zeitschrift für Physik C Particles and Fields, ISSN 0170-9739, E-ISSN 1431-5858, Vol. 10, nr 2, s. 185-187Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is shown that the models for highenergy multiparticle production in which the notion of a hadronicformation time plays a central role are in disagreement with recently published compilations of the rescatter probabilities in 100 GeV/c p d and 200 GeV/c p d collisions.

  • 294. Fredriksson, Sverker
    et al.
    Jändel, Magnus
    The diquark deuteron1982Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 48, nr 1, s. 14-16Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is speculated that an almost stable state of hadronic and nuclear matter can be built from diquarks. It is suggested that this alternative form of matter has already revealed itself in existing experimental data in the form of a diquark "deuteron" with JP=0- and with several other anomalous properties.

  • 295. Fredriksson, Sverker
    et al.
    Jändel, Magnus
    Larsson, Tomas
    A new diquark model for deep inelastic structure functions1982Inngår i: Zeitschrift für Physik C Particles and Fields, ISSN 0170-9739, E-ISSN 1431-5858, Vol. 14, nr 1, s. 35-39Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The bulk of data from deep inelasticep, eD, μp, μN, νp and νN scattering is fitted with a new diquark model of nucleons. The proton is found to be mostly in au(ud) 0 state, where the (ud)0 diquark has spin and isospin zero. There is hence no trace ofSU(6) symmetry among diquarks in nucleons.

  • 296. Fredriksson, Sverker
    et al.
    Jändel, Magnus
    Larsson, Tomas
    Are "Gluon Effects" caused by diquarks?1983Inngår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 51, nr 24, s. 2179-2182Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The possible importance of diquarks in high-energy physics is discussed and it is suggested that this nonperturbative phenomenon can explain the trends in high-energy data that are usually attributed to gluon processes as described by perturbative QCD. Several experimental tests are suggested for discriminating between gluon and diquark phenomena.

  • 297. Fredriksson, Sverker
    et al.
    Jändel, Magnus
    Larsson, Tomas
    Probing spin-1 diquarks in deep inelastic structure functions1983Inngår i: Zeitschrift für Physik C Particles and Fields, ISSN 0170-9739, E-ISSN 1431-5858, Vol. 19, nr 1, s. 53-55Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Within the scope of a new diquark model for deep inelastic structure functions presented by us recently we use the existing data onF 1 ep (x,Q2) to learn about the admixture of spin-1 diquarks in nucleons. It turns out that they are so rare, heavy and extended compared to spin-0 diquarks that they are presumably accidental and not dynamical. Their number and form factors can be understood qualitatively within this picture. Still, the spin-1 diquarks give interesting structures in data and, together with quarks and spin-0 diquarks, carry enough momentum to account for the full nucleon energy. A gluon component is hence not needed in the nucleon!

  • 298. Fredriksson, Sverker
    et al.
    Larsson, Tomas
    A comment on diquark fragmentation1983Inngår i: Physical Review D. Particles and fields, ISSN 0556-2821, E-ISSN 1089-4918, Vol. 28, nr 1, s. 255-256Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    We discuss diquark fragmentation and suggest that a spectator uu system in deep-inelastic lepton-nucleon scattering has a larger breakup probability than a ud system. The reason for this is argued to be that half of the leftover ud systems are in bound (ud)0 diquark configurations, while no such bound uu diquarks exist.

  • 299.
    Frommhold, Lothar
    et al.
    University of Texas, Physics Department.
    Abel, Martin
    University of Texas, Physics Department.
    Wang, Fei
    Physics Department, Beijing Institute of Technology, China.
    Gustafsson, Magnus
    Department of Chemistry, University of Gothenburg.
    Li, Xiaoping
    Department of Chemistry, Michigan State University.
    Hunt, Katherine L.C.
    Department of Chemistry, Michigan State University.
    Infrared atmospheric emission and absorption by simple molecular complexes, from first principles2010Inngår i: Molecular Physics, ISSN 0026-8976, E-ISSN 1362-3028, Vol. 108, nr 17, s. 2265-2272Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Quantum chemical methods are used to obtain the interaction-induced dipole surfaces (IDS) of complexes of two interacting (i.e. colliding) molecules, for example H2–H2, H2–He, etc., collisional complexes, along with their potential energy surfaces (PES). Eight H2 bond distances, from 0.942 to 2.801 bohr, are chosen for each H2 molecule to account for rotovibrational excitations. Rotovibrational matrix elements of these ID and PE surfaces are computed as necessary for the study of supermolecular (‘collision-induced’) absorption spectra of dense hydrogen gas, and of gaseous mixtures of hydrogen and helium, at temperatures up to several thousand kelvin and for frequencies from 0 to those of several H2 overtone bands. Rotovibrational state to state scattering calculations couple the collisional complex perturbatively to single photons. The absorption process causes rotovibrational transitions in one molecule, or simultaneous transitions in both molecules (when H2–H2 collisional complexes are considered). The spectral profiles of tens of thousands of such transitions are computed from first principles. Individual ‘lines’ are very broad so that they overlap substantially, forming a supermolecular quasi-continuum. The comparison of the computed collision-induced absorption (CIA) spectra with existing laboratory measurements at low temperatures (≤ 300 K) shows close agreement so that our results for higher temperatures, where laboratory experiments do not exist, may be used with confidence. Similar calculations of CIA spectra at high temperatures and frequencies are underway for other collisional systems (e.g. H2–H) of interest in astrophysical applications (e.g. ‘cool’ stellar atmospheres). Collision-induced Raman spectra (CIRS) have been similarly obtained; computed Raman spectra also compare favourably with existing laboratory measurements.

  • 300.
    Furustig, Joel
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Dobryden, Illia
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Almqvist, Andreas
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Almqvist, Nils
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Larsson, Roland
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    The measurement of wear using AFM and wear interpretation using a contact mechanics coupled wear model2016Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 350-351, s. 74-81Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Detailed understanding of wear processes is required to improve the wear resistance and lifetime of machine components. Atomic force microscopy (AFM) is used to measure surface height profiles with high precision, before and after a wear experiment. The distribution and depth of wear on steel surfaces is then calculated using a relocation method. A numerical investigation of wear based on Archard's equation is conducted on the same measured surfaces. A good correlation was found between the model and experiment for wear larger than a hundred nm. The wear mechanisms considered in the numerical simulation was thus found to be the cause of the majority of the wear. On the scale of tens of nm the correlation was limited, but the measured wear was still analysed in detail.

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