| 1. |
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| 2. |
- Akselsson, Roland, et al.
(author)
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Luftföroreningar vid svetsning
- 1977
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Reports (other academic/artistic)abstract
- PIXE-analyser kan utföras med utvecklad analysuppställning med noggrannhet och precision av c:a 10 % och med hög analyskapacitet. Ett dataprogram för evaluering av räntgenspektra presenteras. Inverkan av provtjocklek vid PIXE-analys av inhomogena prov har studerats och korrektioner föreslås. Fluorinnehållet i filterprov har bestämts, samtidigt med PIXE-analys, genom utnyttjande av en kärnfysikalisk reaktion som ger resultat med god noggrannhet och precision. Svetsaerosoler har karakteriserats m.h.a. PIXE, ESCA och TEM/EDAX. En uppställning för insamling av svetsaerosoler under utveckling och hittillsvarande resultat indikerar representativ provinsamling med god reproducerbarhet.
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| 3. |
- Carlsson, Lars-Eric, et al.
(author)
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Miljöanalys med hjälp av kärnfysikalisk teknik - PIXE
- 1981
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In: Ordo. - 0345-8970. ; 15:3, s. 3-8
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Journal article (peer-reviewed)abstract
- Under de senaste tio åren har en känslig analysmetod för grundämnen utvecklats vid institutionen för kärnfysik vid LTH. Metoden kallas PIXE (Particle Induced X-ray Emisson) och medger att mycket små förekomster (109 – 1012 g) av grundämnen kanbestämmas i små prov. Metoden är snabb. Ett par minuters analys ger en samtidig bestämning av ett stort antal grundämnen. Analysmetoden används nu i ett stort antal laboratorier runt om i världen och har funnit tillämpning inom en rad olika områden såsom medicin, biologi, yrkes- och omgivningshygien, meteorologi, geologi samt arkeologi. I Lund har metoden huvudsakligen använts för omfattande studier av föroreningar i arbetsmiljö och yttre miljö, varför vi först redogör för vårt arbete inom dessa tillämpningsområden, varefter vi beskriver de fysikaliska principerna för analysmetoden och utvecklingsarbetet med den.
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| 4. |
- Johansson, Anders, 1960-, et al.
(author)
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Factors of r-partite graphs and bounds for the strong chromatic number
- 2010
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In: Ars combinatoria. - : Charles Babbage Research Center. - 0381-7032. ; 95, s. 277-287
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Journal article (peer-reviewed)abstract
- We give an optimal degree condition for a tripartite graph to have a spanning subgraph consisting of complete graphs of order 3. This result is used to give an upper bound of 2 Delta for the strong chromatic number of n vertex graphs with Delta >= n/6.
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| 5. |
- Johansson, Gerd, et al.
(author)
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Luftföroreningar vid svetsning
- 1978
-
Reports (other academic/artistic)abstract
- Beskrivning ges av utveckling av analysuppställning för PIXE-analys, kombinerad med metod för analys av fluor. Vidareutveckling av spektrumevalueringsprogram, HEX, presenteras. Beskrivning av utförda svetsröskarakteriseringar ges. Resultat redovisas för följande belagda elektroder: OK 48.00, OK 38.65 samt OK 61.41. För sistnämnda, rostfria elektrod, presenteras procedur för bestämning av kroms valenstal och löslighet.
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| 6. |
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| 7. |
- Schael, S., et al.
(author)
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Electroweak measurements in electron positron collisions at W-boson-pair energies at LEP
- 2013
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In: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 532:4, s. 119-244
-
Research review (peer-reviewed)abstract
- Electroweak measurements performed with data taken at the electron positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3 fb(-1) collected by the four LEP experiments ALEPH, DELPHI, 13 and OPAL, at centre-of-mass energies ranging from 130 GeV to 209 GeV. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose Einstein correlations between the two W decay systems arising in WW production, are searched for and upper limits on the strength of possible effects are obtained. The data are used to determine fundamental properties of the W boson and the electroweak theory. Among others, the mass and width of the W boson, m(w) and Gamma(w), the branching fraction of W decays to hadrons, B(W -> had), and the trilinear gauge-boson self-couplings g(1)(Z), K-gamma and lambda(gamma), are determined to be: m(w) = 80.376 +/- 0.033 GeV Gamma(w) = 2.195 +/- 0.083 GeV B(W -> had) = 67.41 +/- 0.27% g(1)(Z) = 0.984(-0.020)(+0.018) K-gamma - 0.982 +/- 0.042 lambda(gamma) = 0.022 +/- 0.019. (C) 2013 Elsevier B.V. All rights reserved.
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| 8. |
- Abbasi, R., et al.
(author)
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All-particle cosmic ray energy spectrum measured with 26 IceTop stations
- 2013
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In: Astroparticle physics. - : Elsevier BV. - 0927-6505 .- 1873-2852. ; 44, s. 40-58
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Journal article (peer-reviewed)abstract
- We report on a measurement of the cosmic ray energy spectrum with the IceTop air shower array, the surface component of the IceCube Neutrino Observatory at the South Pole. The data used in this analysis were taken between June and October, 2007, with 26 surface stations operational at that time, corresponding to about one third of the final array. The fiducial area used in this analysis was 0.122 km(2). The analysis investigated the energy spectrum from 1 to 100 PeV measured for three different zenith angle ranges between 0 degrees and 46 degrees. Because of the isotropy of cosmic rays in this energy range the spectra from all zenith angle intervals have to agree. The cosmic-ray energy spectrum was determined under different assumptions on the primary mass composition. Good agreement of spectra in the three zenith angle ranges was found for the assumption of pure proton and a simple two-component model. For zenith angles theta < 30 degrees, where the mass dependence is smallest, the knee in the cosmic ray energy spectrum was observed at about 4 PeV, with a spectral index above the knee of about -3.1. Moreover, an indication of a flattening of the spectrum above 22 PeV was observed.
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| 9. |
- Abbasi, R., et al.
(author)
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Searches for periodic neutrino emission from binary systems with 22 and 40 strings of IceCube
- 2012
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In: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 748:2, s. 118-
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Journal article (peer-reviewed)abstract
- In this paper, we present the results of searches for periodic neutrino emission from a catalog of binary systems. Such modulation, observed in the photon flux, would be caused by the geometry of these systems. In the analysis, the period is fixed by these photon observations, while the phase and duration of the neutrino emission are treated as free parameters to be fit with the data. If the emission occurs during similar to 20% or less of the total period, this analysis achieves better sensitivity than a time-integrated analysis. We use the IceCube data taken from 2007 May 31 to 2008 April 5 with its 22 string configuration and from 2008 April 5 to 2009 May 20 with its 40 string configuration. No evidence for neutrino emission is found, with the strongest excess occurring for Cygnus X-3 at 2.1 sigma significance after accounting for trials. Neutrino flux upper limits for both periodic and time-integrated emission are provided.
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| 10. |
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