| 1. |
- Lundin, Patrik, et al.
(författare)
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Gas Monitoring in Human Body Cavities Using Non-Intrusive Diode Laser Absorption Spectroscopy
- 2012
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Ingår i: 2012 Asia Communications and Photonics Conference. - : IEEE. - 2162-108X. ; , s. 4-7
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Konferensbidrag (refereegranskat)abstract
- Diode laser absorption spectroscopy was utilized for non-intrusive assessment of gas content in human body cavities, including intestines and lungs of a new-born, the mastoid bone, and sinus cavities for monitoring sinusitis recovery in adults.
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| 2. |
- Lundin, Patrik, et al.
(författare)
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Noninvasive monitoring of gas in the lungs and intestines of newborn infants using diode lasers: feasibility study.
- 2013
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Ingår i: Journal of Biomedical Optics. - 1083-3668. ; 18:12
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT. Preterm newborn infants have a high morbidity rate. The most frequently affected organs where free gas is involved are the lungs and intestines. In respiratory distress syndrome, both hyperexpanded and atelectatic (collapsed) areas occur, and in necrotizing enterocolitis, intramural gas may appear in the intestine. Today, these conditions are diagnosed with x-ray radiography. A bed-side, rapid, nonintrusive, and gas-specific technique for in vivo gas sensing would improve diagnosis. We report the use of noninvasive laser spectroscopy, for the first time, to assess gas content in the lungs and intestines of three full-term infants. Water vapor and oxygen were studied with two low-power diode lasers, illuminating the skin and detecting light a few centimeters away. Water vapor was easily detected in the intestines and was also observed in the lungs. The relatively thick chest walls of the infants prevented detection of the weaker oxygen signal in this study. However, results from a previous phantom study, together with scaling of the results presented here to the typical chest-wall thickness of preterm infants, suggest that oxygen also should be detectable in their lungs.
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| 3. |
- Alnis, Janis, et al.
(författare)
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Laser spectroscopy of free molecular oxygen dispersed in wood materials
- 2003
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 77:6-7, s. 691-695
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Tidskriftsartikel (refereegranskat)abstract
- The recently introduced Gas in Scattering Media Absorption Spectroscopy (GASMAS) technique is applied to the study of various wood samples. Molecular oxygen in the pores of the strongly scattering material is detected using diode laser spectroscopy around 760 nm. Diffuse light propagation in these media is studied by time-dispersion measurements. Furthermore, anisotropy related to the fibre structure of wood and gas diffusion properties are studied. Promising extensions of the experiments are discussed.
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| 4. |
- Alnis, J, et al.
(författare)
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Sum-frequency generation with a blue diode laser for mercury spectroscopy at 254 nm
- 2000
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 76:10, s. 1234-1236
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Tidskriftsartikel (refereegranskat)abstract
- Blue diode lasers emitting 5 mW continuous-wave power around 400 nm have recently become available. We report on the use of a blue diode laser together with a 30 mW red diode laser for sum-frequency generation around 254 nm. The ultraviolet power is estimated to be 0.9 nW, and 35 GHz mode-hop-free tuning range is achieved. This is enough to perform high-resolution ultraviolet spectroscopy of mercury isotopes. The possibility to use frequency modulation in the ultraviolet is demonstrated; however, at present the ultraviolet power is too low to give advantages over direct absorption monitoring. Mercury detection at atmospheric pressure is also considered which is of great interest for environmental monitoring. (C) 2000 American Institute of Physics. [S0003-6951(00)02810-2].
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| 5. |
- Bargigia, Ilaria, et al.
(författare)
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Diffuse optical techniques applied to wood characterisation
- 2013
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Ingår i: Journal of Near Infrared Spectroscopy. - : SAGE Publications. - 0967-0335 .- 1751-6552. ; 21:4, s. 259-268
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Tidskriftsartikel (refereegranskat)abstract
- We propose an optical method for non-invasive characterisation of wood samples based on two optical techniques: time-resolved diffuse optical spectroscopy and gas in scattering media absorption spectroscopy. While the latter is sensitive to gases present inside wood pores, the former extracts information on the bulk material regarding light scattering and absorption. Measurements on spruce samples, cut along different wood fibre directions, are presented to show an example of the advantages of this combined approach: by applying these two non-destructive techniques together, in fact, relevant information on wood such as porosity, permeability and moisture content can be assessed. Furthermore, the chemical composition, internal structure and the anisotropy due to the wood fibres can be investigated.
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| 6. |
- Barup, Kerstin, et al.
(författare)
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Multi-disciplinary lidar applications
- 2010
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Ingår i: Laser Applications to Chemical, Security and Environmental Analysis, LACSEA 2010. - 2162-2701. - 9781557528803
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Konferensbidrag (refereegranskat)abstract
- Lidar is a powerful technique normally associated with atmospheric monitoring. However, lidar techniques, also of the laser-induced fluorescence and laser-induced breakdown spectroscopy varieties, provide many new possibilities in unconventional fields including cultural heritage and ecological applications.
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| 7. |
- Biemont, E, et al.
(författare)
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Measurement of radiative lifetimes and determination of transition probabilities of astrophysical interest in HoIII
- 2001
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 1365-2966 .- 0035-8711. ; 328:4, s. 1085-1090
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Tidskriftsartikel (refereegranskat)abstract
- Lifetimes of six levels belonging to the 4f(10)6p configuration of Ho III have been measured for the first time using the time-resolved laser-induced fluorescence method. They are compared with multiconfigurational pseudo-relativistic Hartree-Fock calculations. A very good agreement is found. Using the experimental lifetimes and theoretical branching fractions, a first set of transition probabilities of astrophysical interest has been obtained for this ion.
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| 8. |
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| 9. |
- Grönlund, Rasmus, et al.
(författare)
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Remote LIBS and Raman imaging for assessment of cultural heritage
- 2005
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Ingår i: 2005 Conference on Lasers and Electro-Optics Europe. - 0780389743 ; , s. 684-684
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose to perform remote laser-induced breakdown spectroscopy (LIBS) and Raman imaging of historical monuments to assess the state of a building. The lidar system is equipped with a Nd:YAG pumped optical parametrical oscillator (OPO) system, allowing laser radiation in the wavelength range 220 nm-4 μm. The laser radiation can be sent through a roof-top dome which can steer the radiation onto the point of interest
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| 10. |
- Guan, Zuguang, et al.
(författare)
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Vertical lidar sounding of atomic mercury and nitric oxide in a major Chinese city
- 2010
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 101:1-2, s. 465-470
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Tidskriftsartikel (refereegranskat)abstract
- Vertical range-resolved measurements of atmospheric pollutants were performed in a major city in southern China, employing a lidar system operating with an optical parametric oscillator transmitter. Recordings of atomic mercury (Hg) and nitric oxide (NO) absorbing in the deep-UV region were taken, yielding concentration profiles only attainable with lidar techniques. In particular, the potential influence of molecular oxygen in low-concentration mercury monitoring was elucidated. Diurnal observations are discussed and presented together with weather parameters.
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