| 1. |
- Bartosik, M., et al.
(författare)
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Interface controlled microstructure evolution in nanolayered thin films
- 2016
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Ingår i: Scripta Materialia. - : PERGAMON-ELSEVIER SCIENCE LTD. - 1359-6462 .- 1872-8456. ; 123, s. 13-16
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Tidskriftsartikel (refereegranskat)abstract
- X-ray nano-diffraction and transmission electron microscopy were conducted along the thickness of a similar to 4 pm thick CrN/AlN multilayer with continuously increasing AlN layer thicknesses from similar to 1 to 15 nm on similar to 7 nm thick CrN template layers. The experiments reveal coherent growth, large columnar grains extending over several (bi-)layers for thin AlN layer thicknesses below similar to 4 nm. Above similar to 4 nm, the nucleation of the thermodynamically stable wurtzite structured AlN is favored, leading to coherency breakdown and reduction of the overall strains, disrupting the columnar microstructure and limiting the maximum grain size in film growth direction to the layer thickness. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd.
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| 2. |
- Bergstrom, H, et al.
(författare)
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Detection of carbon using amplified laser-induced fluorescence
- 1989
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Ingår i: Chemical Physics Letters. - 0009-2614. ; 155, s. 27-31
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Tidskriftsartikel (refereegranskat)abstract
- Radiative lifetimes and stimulated emission have been studied in two-photon-excited carbon atoms. A strong fluorescence enhancement was detected in the direction of the exciting laser beam. Rate equations for the energy levels involved have been calculated in order to obtain number densities from the emitted light. Lifetimes were measured for the 2p3p 3p and 3D states and for the A 3[Pi]g state of the C2 molecule.
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| 3. |
- Bergstrom, H, et al.
(författare)
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Investigations of radiative lifetimes in the 3p 5p configuration of neutral silicon
- 1989
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Ingår i: Zeitschrift für Physik D Atoms, Molecules and Clusters. - 0178-7683. ; 13:1, s. 29-31
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Tidskriftsartikel (refereegranskat)abstract
- Lifetimes for the3S1,3P0, 1, 2 and3D1, 2, 3 states in the 3s23p5p configuration of silicon have been determined using stepwise dye laser excitation and time resolved detection. A comparison is made with theoretical values, calculated using multi-configuration Hartree-Fock wavefunctions. Laser-evaporation was used to produce free silicon atoms by focusing a Nd: YAG laser on a rotating silicon target.
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| 6. |
- Engstrom, G., et al.
(författare)
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Cardiovagal Function Measured by the Deep Breathing Test: Relationships With Coronary Atherosclerosis
- 2022
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Ingår i: Journal of the American Heart Association. - : Ovid Technologies (Wolters Kluwer Health). - 2047-9980. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- Background The cardiovagal function can be assessed by quantification of respiratory sinus arrhythmia (RSA) during a deep breathing test. However, population studies of RSA and coronary atherosclerosis are lacking. This population-based study examined the relationship between RSA during deep breathing and coronary atherosclerosis, assessed by coronary artery calcium score (CACS). Methods and Results SCAPIS (Swedish Cardiopulmonary Bioimage Study) randomly invited men and women aged 50 to 64 years from the general population. CACS was obtained from computed tomography scanning, and deep breathing tests were performed in 4654 individuals. Expiration-inspiration differences (E-Is) of heart rates were calculated, and reduced RSA was defined as E-I in the lowest decile of the population. The relationship between reduced RSA and CACS (CACS >= 100 or CACS >= 300) was calculated using multivariable-adjusted logistic regression. The proportion of CACS >= 100 was 24% in the lowest decile of E-I and 12% in individuals with E-I above the lowest decile (P<0.001), and the proportion of CACS >= 300 was 12% and 4.8%, respectively (P<0.001). The adjusted odds ratio (OR) for CACS >= 100 was 1.42 (95% CI, 1.10-1.84) and the adjusted OR for CACS >= 300 was 1.62 (95% CI, 1.15-2.28), when comparing the lowest E-I decile with deciles 2 to 10. Adjusted ORs per 1 SD lower E-I were 1.17 (P=0.001) for CACS >= 100 and 1.28 (P=0.001) for CACS >= 300. Conclusions Low RSA during deep breathing is associated with increased coronary atherosclerosis as assessed by CACS, independently of traditional cardiovascular risk factors. Cardiovagal dysfunction could be a prevalent and modifiable risk factor for coronary atherosclerosis in the general population.
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| 7. |
- Jarnac, A., et al.
(författare)
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Communication : Demonstration of a 20 ps X-ray switch based on a photoacoustic transducer
- 2017
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Ingår i: Structural Dynamics. - : AIP Publishing. - 2329-7778. ; 4:5
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Tidskriftsartikel (refereegranskat)abstract
- We have studied an X-ray switch based on a gold coated indium antimonide crystal using time-resolved X-ray diffraction and demonstrated that the switch could reduce the pulse duration of a 100 ps X-ray pulse down to 20 ps with a peak reflectivity of 8%. We have used a dynamical diffraction code to predict the performance of the switch, which was then confirmed experimentally. The experiment was carried out at the FemtoMAX beamline at the short-pulse facility of the MAX IV laboratory. The performance and limitation of the switch are discussed in terms of acoustic transport properties between the two materials and the electron transport properties of gold.
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| 10. |
- Persson, A. I H, et al.
(författare)
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Studies of electron diffusion in photo-excited Ni using time-resolved X-ray diffraction
- 2016
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 109:20
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Tidskriftsartikel (refereegranskat)abstract
- We show that the heat deposition profile in a laser-excited metal can be determined by time-resolved X-ray diffraction. In this study, we investigated the electron diffusion in a 150 nm thick nickel film deposited on an indium antimonide substrate. A strain wave that mimics the heat deposition profile is generated in the metal and propagates into the InSb, where it influences the temporal profile of X-rays diffracted from InSb. We found that the strain pulse significantly deviated from a simple exponential profile, and that the two-temperature model was needed to reproduce the measured heat deposition profile. Experimental results were compared to simulations based on the two-temperature model carried out using commercial finite-element software packages and on-line dynamical diffraction tools. To reproduce the experimental data, the electron-phonon coupling factor was lowered compared to previously measured values. The experiment was carried out at a third-generation synchrotron radiation source using a high-brightness beam and an ultrafast X-ray streak camera with a temporal resolution of 3 ps.
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