| 1. |
- Alberdi, A., et al.
(författare)
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The high-frequency compact radio structure of the peculiar quasar 4C 39.25
- 1997
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Ingår i: Astronomy and Astrophysics. - : Springer-Verlag. - 0004-6361 .- 1432-0746. ; 327:2, s. 513-521
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Tidskriftsartikel (refereegranskat)abstract
- We present new high angular resolution images of the compact non-thermal radio source 4C 39.25 obtained from VLBI observations at λ1.3cm, λ7mm, and λ3mm wavelengths. These maps and Gaussian model-fits show that the milli-arcsecond to sub-milliarcsecond structure of 4C 39.25 consists of a complex bent core-jet structure with embedded moving and stationary VLBI components. Facilitated by the small observing beams and high angular resolutions obtained at mm-wavelengths, we measured the relative positions of the jet components with an accuracy of a few hundred micro-arcseconds. This allows the detailed followup of the ongoing merging process of a westward superluminally moving component (b_) with a stationary component a_, located at ~2.9 mas east of the putative core d_. In contrast to the other components of the structure with steeper spectra, the westernmost component d_ exhibits an inverted spectrum peaking between λ7mm and λ3mm, thus further supporting its identification as the VLBI core, self-absorbed at longer wavelengths. From two VLBI maps obtained nearly simultaneously at λ7mm and λ1.3cm, we made the first spectral index map of 4C 39.25 in this wavelength regime. The main characteristics of the spectral index distribution of the jet are pronounced changes of the spectral index between orientations parallel and transverse to the jet axis. Near the merging components a_ and b_ the spectral index steepens with increasing separation from d_. However, in the bridge of emission c_, which connects d_ with a_ and b_, the spectral index gradient has a direction transverse to the jet axis, suggesting a frequency dependent jet curvature and edge-brightening. A brief discussion of this behaviour within current jet models is presented.
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| 2. |
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| 3. |
- Bååth, Lars B.
(författare)
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Analys av avgaser med mikrovågspektroskopi
- 2004
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Rapport (refereegranskat)abstract
- Inom projektet har hittills genomförts följande aktiviteter:Inhämtat teoretiska kunskaper inom området mikrovågsteknikGenomfört studier avseende vilka molekyler som är av intresse för stål- och metallindustrin att mäta på.Kontrollerat mot JPL databas samt NBS om dessa molekyler finns definierade i mikrovågsområdet av det elektromagnetiska spektret och då på vilka frekvenser.Designat och tillverkat en sensor, bestående av antenner, mixer samt LO, som klarar av att mäta vid de relevanta molekylära frekvenserna.Testat och utvärderat sensortekniken på laboratorienivå avseende signalkarak- täristik.Genomfört pilotförsök på MEFOS: i. Höga gastemperaturer; ii. Olika gaskoncentrationerGenomförtverksförsök: i. LKAB, Rotary Kiln; ii. Boliden Mineral, KopparkonverterUtvärderat försöksdata
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| 4. |
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| 5. |
- Bååth, Lars B., et al.
(författare)
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Imaging with Interferometers
- 1998
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Ingår i: Proceedings SSAB Symposium on Image Analysis. ; , s. 4-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A scanning device based on changes in the reflections of an electromagnetic wave for use on wood the image can be calculated.
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| 6. |
- Bååth, Lars B., 1948-
(författare)
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Method and device for contactless level and interface detection
- 2006
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Patent (populärvet., debatt m.m.)abstract
- Method and apparatus for determining the thickness of material layers of a container-held substance comprising a first material disposed in an upper layer and a second material disposed in a lower layer, by transmitting a radio signal through the substance towards a container portion; receiving reflected signals from a surface of the upper layer, a surface of the second layer, and the container portion; varying the frequency of the transmitted signal to determine phase displacement between transmitted and reflected signals; determining optical distances to the surfaces and the container portion, dependent on the phase displacements; determining the thickness of one of said layers dependent on phase displacement through and index of refraction of that layer; and determining the thickness of the other layer dependent on the thickness of said one of said layers.
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| 7. |
- Bååth, Lars B., 1948-
(författare)
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Method for analysing a substance in a container
- 2006
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Patent (populärvet., debatt m.m.)abstract
- Method and apparatus for analyzing a substance in a container, the method comprising the steps of: disposing antenna means (3) at a predetermined geometrical distance (L) from a container portion (13); transmitting a signal from said antenna means through a surface portion (12) of the substance towards said container portion; receiving a first reflected signal in said antenna means from said container portion; determining a geometrical distance (L1) from the surface portion to the container portion; varying the frequency of the transmitted signal to determine a first phase displacement between the transmitted signal and the first reflected signal; determining an optical distance from the surface portion to the container portion based on the first phase displacement; and determining the index of refraction (nt) of said substance based on the optical and geometrical from the surface portion to the container portion.
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| 8. |
- Bååth, Lars B., 1948-
(författare)
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mm VLBI
- 1993
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Ingår i: VLBI Technology – Progress and Future Observational Possibilities. - Tokyo : Terra Scientific Publishing Company. ; , s. 70-74
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Bokkapitel (refereegranskat)abstract
- Very long Baseline Interferometry (VLBI) has now made its break-through into the mm wavelength regime. A global VLBI array has produced maps of radio sources at 3 mm since 1988 and development is under way to improve the sensitivity for VLBI also at 1 mm. This contribution discusses the present state of mm VLBI and the future developments.
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| 9. |
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| 10. |
- Bååth, Lars B.
(författare)
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Radio Wave Interferometer Measurements of Slag Depth
- 2003
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Ingår i: Iron & Steel society international technology conference and exposition 2003. - : Iron and Steel Society. ; , s. 875-882
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- During the past decade software to control metallurgical processes has improved to require new physical sensors for feedback. We present a non-invasive interferometric technique to simultaneously measure multiple levels in dynamic metallurgical processes, e.g. the foam-, slag-, emulsion-, and steel-layers in furnaces. The measurements are continuous and on-line during production.
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