| 1. |
- Andersson, Åke, et al.
(författare)
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The MAX II synchrotron radiation storage ring
- 1994
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 343:2-3, s. 644-649
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Tidskriftsartikel (refereegranskat)abstract
- A 1.5 GeV third generation storage ring optimised for the VUV and soft X-ray spectral region is currently being built at MAX-lab. The magnet lattice, ring architecture and production choices are optimised to fit within rather tight boundary conditions without sacrificing performance. In this paper, the magnet lattice, light characteristics, injection and technical solutions for the ring are presented.
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| 2. |
- Holst, Ulla, et al.
(författare)
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Recursive estimation in switching autoregressions with Markov regime
- 1994
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Ingår i: Journal of Time Series Analysis. - : Wiley. - 0143-9782 .- 1467-9892. ; 15:5, s. 489-506
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Tidskriftsartikel (refereegranskat)abstract
- A hidden Markov regime is a Markov process that governs the time or space dependent distributions of an observed stochastic process. We propose a recursive algorithm for parameter estimation in a switching autoregressive process governed by a hidden Markov chain. A common approach to the recursive estimation problem is to base the estimation on suboptimal modifications of Kalman filtering techniques. The main idea in this paper is to use the maximum likelihood method and from this develop a recursive EM algorithm.
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| 3. |
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| 4. |
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| 5. |
- Lindgren, Lars-Erik, et al.
(författare)
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Accuracy and efficiency in computational plasticity
- 1991
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Ingår i: Proceedings of the International Conference on Mechanics of Solids and Structures. - Singapore : World Scientific and Engineering Academy and Society. - 9810207387
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Konferensbidrag (refereegranskat)
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| 6. |
- Lindgren, Lars-Erik, et al.
(författare)
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Computational model of flame-cutting
- 1993
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Ingår i: Journal of engineering materials and technology. - : ASME International. - 0094-4289 .- 1528-8889. ; 115:4, s. 440-445
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Tidskriftsartikel (refereegranskat)abstract
- A computational model for simulation of flame-cutting has been developed. Two different cutting conditions are compared with respect to the residual stresses. The first case is a plate cut at room temperature and the other is the cutting of a preheated plate. The model depends on measured micro-structure to estimate the required heat input. The model is verified by comparing the calculations for the preheated plate with experimentally obtained residual stresses. Lower residual stresses in the preheated plate prevents subsequent cracking
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| 7. |
- Lindgren, Mikael, 1963
(författare)
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Picosecond Infrared Detection and Optical Mixing in YBa2Cu3O7-δ Thin Films
- 1994
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Studies of infrared photoresponse in high Tc superconducting YBa2Cu3O7-.delta. (YBCO) thin films are presented in this dissertation. Detectors fabricated from YBCO films of different thicknesses have been investigated, in terms of responsitivity, speed, and detection mechanisms, by the use of semiconductor lasers at near infrared wavelengths and a CO2 laser at 10.6 µm wavelength. Granular films, thicker than the optical penetration depth, showed only bolometric response and response times in the nanosecond range. Detectors patterned in films from different laboratories displayed large variations in responsivity, which could not be explained by material characterization. When epitaxial films of the same thickness as the optical penetration depth were used, major improvements were observed. Both the speed and the responsivity were considerably higher. The response was found to be mainly bolometric but, for the shortest laser pulses, indications of a vortex depairing response mechanism was found. By the use of even thinner films and a special detector structure, a high speed detection mechanism attributed to nonequilibrium phenomena was revealed. An electron heating mechanism, with the quasiparticles at an elevated temperature compared with the phonons of the superconductor, fitted well with our measured data. Furthermore, the detector was operated as a mixer for infrared radiation at intermediate frequencies up to 18 GHz. Based on the electron heating model, the bandwidth of the electron heating mechanism was calculated to be 130 GHz. The photoresponse from a single YBCO grain boundary Josephson junction was also studied. A bolometric response was found, in which the critical current of the junction was reduced as the impinging radiation raised the temperature. The flexibility of a Josephson junction type bolometer was also discussed.
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| 8. |
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