| 1. |
- Akselsson, Roland, et al.
(författare)
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Fysikaliska faktorer
- 1994
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Ingår i: Arbete Människa Teknik. - 9175224143 ; , s. 45-113
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 2. |
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| 3. |
- Dordlofva, Bengt, et al.
(författare)
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Arrangement for Frequency Planning in Cellular Systems
- 1999
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Patent (populärvet., debatt m.m.)abstract
- The invention relates to an arrangement for frequency planning in cellular systems using a mix of wide and narrow antenna beams. The arrangement employs a dual frequency reuse for the respective wide and narrow antenna beams. According to the invention, a first frequency group is allocated to a cluster with a reuse distance sufficient for narrow beam channels and a second frequency group is allocated to a larger cluster with a reuse distance sufficent for wide beam channels. The second frequency group is a subdivision of and contained in the first frequency group. The second frequency group is the only frequency group available for wide beam channels, while all the frequencies of the two groups are available for the narrow beams channels. Generally, the wide beams are used for control channels and the narrow beams are used for traffic channels. A frequency planning in accordance with the invention makes it possible to use narrow beam traffic channels more efficiently compared to known state of the art methods which results in improved trunking efficiency.
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| 4. |
- Albertsson, Per, 1956, et al.
(författare)
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Morbidity and use of medical resources in patients with chest pain and normal or near-normal coronary arteries.
- 1997
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Ingår i: The American journal of cardiology. - : Excerpta Medica, Inc.. - 0002-9149 .- 1879-1913. ; 79:3, s. 299-304
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Tidskriftsartikel (refereegranskat)abstract
- To evaluate morbidity and use of medical resources in patients with chest pain and normal or near-normal coronary angiograms: 2,639 consecutive patients who underwent coronary angiograms due to chest pain were registered. Two years thereafter all patients who showed normal or near-normal coronary angiograms were approached with a questionnaire regarding hospitalization during the last 4 years (2 years before and 2 years after angiography). All medical files were also examined. Of the patients who underwent angiography, 163 (6%) had no significant stenoses, and of these, 113 showed complete normal angiograms and 50 showed mild (i.e. <50%) stenoses. During the 2 years before diagnostic angiogram, 66% of the patients were hospitalized compared with only 35% during 2 years after angiography (p <0.001). The reduction in hospitalization was due to curtailed utilization of medical resources for cardiac reasons; mean days in hospital was 6.6 days before angiography versus 2.8 days after (p <0.001). There were no significant differences in hospitalization when comparing patients with mild stenoses and completely normal angiograms. There were, furthermore, no differences between patients with positive or negative exercise tests. Thus, the need for hospitalization is significantly reduced after a diagnostic angiogram reveals normal or near-normal coronary arteries.
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| 5. |
- Altraja, Alan, et al.
(författare)
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Expression of laminins in the airways in various types of asthmatic patients: A morphometric study
- 1996
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Ingår i: American Journal of Respiratory Cell and Molecular Biology. - 1044-1549 .- 1535-4989. ; 15:4, s. 482-488
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Tidskriftsartikel (refereegranskat)abstract
- Laminins (Ln) are crucial in airway morphogenesis. Because they are able to interact with inflammatory cells, they are likely to participate in inflammation accompanied by airway structural remodeling in asthma. Taking biopsies and using immunohistochemistry and quantitative image analysis, we characterized the distribution of Ln chains alpha 1, alpha 2, and beta 2 in the bronchial mucosa of patients with seasonal (n = 17), early occupational (n = 8), and chronic asthma (n = 16) for comparison with that of normal controls (n = 8). In all asthmatic patients, both Ln chains alpha 1 and beta 2 were confined to the superficial margin of the basement membrane (BM), blood vessels, and smooth muscle. The thickness of Ln beta 2 expression in BM was significantly greater in patients with chronic (1.9 +/- 0.1 microns; P < 0.001) and occupational asthma (1.7 +/- 0.1 microns; P < 0.05) than in controls (0.4 +/- 0.3 microns). Only in patients with occupational asthma was the thickness of the Ln alpha 1 layer (2.3 +/- 0.2 microns; mean +/- SEM) significantly different from that in controls (1.4 +/- 0.5 microns; P < 0.05). There was no immunoreactivity for the Ln alpha 2 chain in controls or patients with mild asthma, but in clinically severe chronic asthma we found a discontinuous staining along the epithelial margin of the BM. Since Ln chains alpha 2 and beta 2 appear to function only during morphogenesis, increased expression of these Ln chains in adult asthma patients suggests accelerated tissue turnover in the airways, possibly as a result of airway inflammation in asthma.
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| 6. |
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| 7. |
- Barclay, Susan A, et al.
(författare)
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The shape of the proximal isovelocity surface area varies with regurgitant orifice size and distance from orifice : computer simulation and model experiments with color M-mode technique.
- 1993
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Ingår i: Journal of the American Society of Echocardiography. - 0894-7317 .- 1097-6795. ; 6:4, s. 433-445
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Tidskriftsartikel (refereegranskat)abstract
- The hemispheric proximal isovelocity surface area method for quantification of mitral regurgitant flow (i.e., Qc = 2 pi r2v), where 2 pi r2 is the surface area and v is the velocity at radius r, was investigated as distance from the orifice was increased. Computer simulations and steady flow model experiments were performed for orifices of 4, 6, and 8 mm. Flow rates derived from the centerline velocity and hemispheric assumption were compared with true flow rates. Proximal isovelocity surface area shape varied as distance from each orifice was increased and could only be approximated from the hemispheric equation when a certain distance was exceeded: > 7, > 10, and > 12 mm for the 4, 6, and 8 mm orifices, respectively. Prediction of relative error showed that the best radial zone at which to make measurements was 5 to 9, 6 to 14 and 7 to 17 mm for the 4, 6, and 8 mm orifices, respectively. Although effects of a nonhemispheric shape could be compensated for by use of a correction factor, a radius of 8 to 9 mm can be recommended without the use of a correction factor over all orifices studied if a deviation in calculated as compared with true flow of 15% is considered acceptable. These measurements therefore have implications for the technique in clinical practice.
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| 8. |
- Bojrup, Martin, et al.
(författare)
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A Dual Purpose battery Charger for Electric Vehicles
- 1998
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Ingår i: PESC 98 Conference Proceedings. ; , s. 565-570
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Konferensbidrag (refereegranskat)abstract
- Abstract in UndeterminedA dual purpose, high power, off board battery charger for electric vehicles is presented. For higher viability and increased usage of the charger, grid conditioning capabilities are included in the concept. Conventional power electronic converter topologies are used in a new application, which combines fast EV battery charging with active filtering. Furthermore bi-directional power flow capabilities are provided to accommodate grid peak power requirements. Both simulation and experimental results are presented in this paper which demonstrate the capabilities of the new charger.
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| 9. |
- Bojrup, M., et al.
(författare)
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Battery Chargers for Electric Vehicles - A Project Description
- 1996
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Ingår i: [Host publication title missing]. ; , s. 295-298
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Konferensbidrag (refereegranskat)abstract
- A battery charger for electric vehicles is to be designed. The charger should have advantageous impact on the utility grid, for example filtering capabilities, reactive power compensation, etc. several battery chargers forms a network where communication between the chargers and the vehicles and some distribution level master controller is an important issue. A possible battery charger topology is presented. This text gives a description of the project but does not present any results.
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| 10. |
- Bojrup, Martin, et al.
(författare)
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Multiple Rotating Integrator Controller for Active Filters
- 1999
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Ingår i: EPE 99 Conference Proceedings.
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Konferensbidrag (refereegranskat)abstract
- Abstract in UndeterminedA controller scheme based on multiple rotating integrators (MRI) for an active filter is presented, analysed and evaluated. The inherent performance of integrators in the synchronous reference dq-frame for reduction of steady state errors are used in multiple rotating reference frames in order to compensate harmonics to obtain a steady state error equal to zero. Both measurements and simulations clearly verify the advantageous performance in comparison to presently used active filters. Particularly in experimental verification, the MRI controller structure outperforms the alternative methods due to its low sensitivity to parameter variation and non linear properties of the system. This is particularly important since the superiority of the MRI structure is not fully revealed only by simulation. It is shown that the MRI structure do suppress harmonics to the measurement noise level.
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