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| 2. |
- Caraeni, D., et al.
(författare)
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LES of spray in compressible flows on unstructured grids
- 1999
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Ingår i: 30th Fluid Dynamics Conference. - 9780000000002
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Konferensbidrag (refereegranskat)abstract
- In this paper we report some results of our numerical simulations of sprays in compressible flows using Large Eddy Simulation. The combined LES- and spray code has been applied to the computation of the flow and spray injection into a swirl generator of a gas-turbine. The interaction between the spray jet and the flow field has been investigated. A dynamic SGS model has been used and results have been compared with the experimental data.
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| 3. |
- Erlandsson, Marcus, et al.
(författare)
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Surveillance of Antibiotic Resistance in ICUs in Southeastern Sweden
- 1999
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Ingår i: Acta Anaesthesiol Scand. - : Wiley. ; 43:8, s. 815-820
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Tidskriftsartikel (refereegranskat)abstract
- Background: A study was designed to assess a computer-based program for continuous registration of antibiotic resistance, statistics concerning severity of illness, and consumption of antibacterial drugs. Methods: The frequency of antibiotic resistance among bacteria in eight ICUs in southeastern Sweden was investigated yearly from 1995 through 1997. The antibiotic consumption in the ICUs was registered as defined daily doses (DDD) and compared to severity of illness (APACHE-II scores). Results: There was a statistically significant increase in ampicillin resistance among Enterococcus spp. between 1996 and 1997, which was due to a shift from Enterococcus faecalis to Enterococcus faecium. A high prevalence of resistance among coagulase-negative staphylococci to oxacillin (≈ 70%), ciprofloxacin (≈ 50%), fucidic acid (≈ 50%) and netilmicin (≈ 30%) was seen in all ICUs during the whole study period. There was a statistically significant increase in ciprofloxacin resistance among Escherichia coli and Enterococcus spp. The resistance among Enterobacter spp. to cefotaxime decreased but this change was not statistically significant. Efforts were made to avoid betalactam antibiotics, except carbapenems, for treatment of infections caused by Enterobacter spp. and the consumption of cephalosporins decreased whereas the consumption of carbapenems increased. The total antibiotic consumption decreased by 2.5% during the study period. There was no correlation between APACHE II scores and antibiotic consumption. Conclusions: Each ICU within a hospital ought to have a program for "on-line" antibiotic resistance surveillance of drugs used in that unit so that changes in empirical treatment can be made when there is an increase in antibiotic-resistant isolates within that unit.
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| 4. |
- Hoffmann, L, et al.
(författare)
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Local vibrational modes of a dicarbon-hydrogen center in crystalline silicon
- 1999
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 274, s. 275-278
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Tidskriftsartikel (refereegranskat)abstract
- Carbon-doped silicon irradiated with electrons at room temperature and subsequently implanted with protons has been studied by infrared absorption spectroscopy. Isochronal annealing in the temperature range from 400 degrees C to 800 degrees C has revealed an absorption line at 2967 cm(-1). When protons are substituted by deuterons, the line shifts down in frequency to 2211 cm(-1) and co-implantation of protons and deuterons gives rise to an additional line at 2218 cm(-1) Isotope shifts and similar annealing characteristics of the three lines show that the 2967 cm(-1) line represents a local vibrational mode of a defect, which contains two equivalent hydrogen atoms. In samples co-doped with C-12 and C-13, an additional mode is observed at 2963 cm(-1), which is about halfway between the modes involving only C-12 or C-13. From the relative intensities of the isotope-shifted modes in silicon co-doped with C-12 and C-13, it is concluded that the center contains two equivalent carbon atoms. The center is tentatively identified as two equivalent hydrogen atoms bound to two neighboring carbon atoms at substitutional sites. (C) 1999 Elsevier Science B.V. All rights reserved.
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| 5. |
- Hoffmann, L., et al.
(författare)
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Substitutional carbon in Ge and Si1-xGex
- 1997
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Ingår i: Defects in semiconductors. - : Trans Tech Publications Inc.. ; , s. 97-102
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Konferensbidrag (refereegranskat)abstract
- In the present work, carbon is implanted into monocrystalline Ge and into relaxed epitaxial MBE-grown Si1-xGex. The samples are studied with infrared absorption spectroscopy along with ion-channeling studies on the Ge samples. Finally, ab-initio local density functional cluster theory is applied to calculate the structure and the local vibrational modes of substitutional carbon, Cs, in Ge. After implantation of 12C+ in Ge at room temperature and subsequent annealing at 350°C, a sharp absorption line is observed at 531 cm-1. By isotope substitution, it is concluded that the 531 cm-1 line represents a local vibrational mode of a single carbon atom. From ion-channeling measurements on samples annealed at 450°C, it is found that 31±3 % of the carbon atoms are located at substitutional sites. The population of the substitutional site and the intensity of the 531 cm-1 mode have identical annealing behavior and it is concluded that the 531 cm-1 mode is the three-dimensional T2 stretch mode of Cs in Ge. The calculated frequency and isotope shift for this mode are in good agreement with the observations. In Si0.65Ge0.35, two broad absorption lines are observed at ∼551 and ∼592 cm-1 after implantation of 12C+ and subsequent annealing at 550°C. From measurements on samples implanted with 13C+ and coimplanted with 12C+ and 13C+ we conclude that these lines represent local vibrational modes of defects containing a single carbon atom. In 13C+ implanted Si1-xGex samples that contain 15 to 50 % Ge a number of modes are observed in a frequency range from ∼510 to ∼610 cm-1, i.e., in the range of Cs in Ge and in Si. From the experimental findings it is concluded that substitutional carbon in Si1-xGex binds to both Si and Ge.
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| 6. |
- Hoffmann, L., et al.
(författare)
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Substitutional carbon in germanium
- 1997
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 55:17, s. 11167-11173
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Tidskriftsartikel (refereegranskat)abstract
- Carbon impurities implanted into single-crystalline germanium are studied with infrared absorption spectroscopy and ion channeling. After implantation of 12C+ at room temperature and subsequent annealing at 350 °C, a sharp infrared absorption line is observed at 531 cm-1. When 12C+ is substituted by 13C+, the line shifts down in frequency to 512 cm-1 and co-implantation of 12C+ and 13C+ does not give rise to additional lines. Therefore, the 531-cm-1 line represents a local vibrational mode of a defect containing a single carbon atom. Channeling measurements are carried out around the 〈100〉, 〈110〉, and 〈111〉 axes in 12C+-implanted samples annealed at 450 °C. The analysis of the data shows that 31±3 % of the carbon atoms are located at substitutional sites, while the remaining carbon atoms appear to be located randomly. The population of the substitutional site and the intensity of the 531-cm-1 mode have identical temperature dependencies. It is concluded that the 531-cm-1 mode is the three-dimensional T2 stretch mode of substitutional carbon. The effective charge of the mode is determined to be (3.4±0.5)e.mAb initio local density functional cluster theory is applied to calculate the structure and the local vibrational modes of substitutional carbon in germanium. The calculated frequencies and isotope shifts for the T2 stretch mode are in good agreement with the observations.
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| 7. |
- Hoffmann, L., et al.
(författare)
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Substitutional carbon in Si1-xGex
- 1999
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 60:19, s. 13573-13581
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Tidskriftsartikel (refereegranskat)abstract
- Local vibrational modes of carbon impurities in relaxed Si1-xGex have been studied with infrared absorption spectroscopy in the composition range 0.05≤x≤0.50. Carbon modes with frequencies in the range 512-600 cm-1 are observed in 13C+-implanted Si1-xGex after annealing at 550°C. Measurements on samples coimplanted with 12C+ and 13C+ show that these modes originate from defects containing a single carbon atom and from the variation of the mode frequencies with composition x, the modes are assigned to substitutional carbon in Si1-xGex. Based on the frequencies obtained from a simple vibrational model, the observed modes are assigned to specific combinations of the four Si and Ge neighbors to the carbon. The intensities of the modes indicate that the combination of the four neighbors deviates from a random distribution. Ab initio local-density-functional cluster theory has been applied to calculate the structure and the local mode frequencies of substitutional carbon with n Ge and 4-n Si neighbors in a Si and a Ge cluster. The calculated frequencies are ∼9% higher than those observed, but the ordering and the splitting of the mode frequencies agree with our assignments.
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| 8. |
- Jonsdottir, Ingibjörg H, 1966, et al.
(författare)
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Increase in nitric oxide formation after chronic voluntary exercise in spontaneously hypertensive rats.
- 1998
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Ingår i: Acta physiologica Scandinavica. - 0001-6772. ; 162:2, s. 149-53
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Tidskriftsartikel (refereegranskat)abstract
- The effect of chronic voluntary exercise on the plasma level of nitrate, a major stable metabolite of nitric oxide (NO) was studied in spontaneously hypertensive rats (SHR). Exercise consisted of spontaneous running in wheels for 3-35 days. Blood samples were collected after 3, 7, 14, 21 and 35 days of exercise and all samples were drawn after the running wheel had been locked during the preceding 12 h. The plasma nitrate level was significantly (P < 0.05) elevated in SHR after 35 days of exercise. Surprisingly after 7 days of exercise a significant (P < 0.001) decrease in the nitrate level in plasma was noted. Further research is needed to elucidate this biphasic change in nitrate seen in this study. The elevated level of plasma nitrate seen after 35 days of voluntary exercise was still present up to 36 h after termination of exercise. We conclude that exercise training in SHR elicits an enhanced formation of NO.
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| 9. |
- Magnusson, P, et al.
(författare)
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Photometric observations and modeling of asteroid 1620 Geographos
- 1996
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Ingår i: ICARUS. - : ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS. - 0019-1035. ; 123:1, s. 227-244
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Photometric observations of 1620 Geographos in 1993 and 1993 are presented and, in combination with previously published data, are used to derive models of Geographos, We estimate that the sidereal period of rotation is 0.21763860 +/- 0.00000003 days (5(h
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