| 1. |
- Enfors, Sven-Olof, et al.
(författare)
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Physiological responses to mixing in large scale bioreactors
- 2001
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Ingår i: Journal of Biotechnology. - 0168-1656 .- 1873-4863. ; 85:2, s. 175-185
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Tidskriftsartikel (refereegranskat)abstract
- Escherichia coli fed-batch cultivations at 22 m(3) scale were compared to corresponding laboratory scale processes and cultivations using a scale-down reactor furnished with a high-glucose concentration zone to mimic the conditions in a feed zone of the large bioreactor. Formate accumulated in the large reactor, indicating the existence of oxygen limitation zones. It is suggested that the reduced biomass yield at large scale partly is due to repeated production/reassimilation of acetate from overflow metabolism and mixed acid fermentation products due to local moving zones with oxygen limitation. The conditions that generated mixed-acid fermentation in the scale-down reactor also induced a number of stress responses, monitored by analysis of mRNA of selected stress induced genes. The stress responses were relaxed when the cells returned to the substrate limited and oxygen sufficient compartment of the reactor. Corresponding analysis in the large reactor showed that the concentration of mRNA of four stress induced genes was lowest at the sampling port most distant from the feed zone. It is assumed that repeated induction/relaxation of stress responses in a large bioreactor may contribute to altered physiological properties of the cells grown in large-scale bioreactor. Flow cytometric analysis revealed reduced damage with respect to cytoplasmic membrane potential and integrity in cells grown in the dynamic environments of the large scale reactor and the scale-down reactor.
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| 2. |
- Wang, Ke, et al.
(författare)
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100-112 Gbit/s complete ETDM systems based on monolithically integrated transmitter and receiver modules
- 2011
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Ingår i: Journal of Beijing Institute of Technology (English Edition). - 1004-0579. ; 20:3, s. 410-414
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Tidskriftsartikel (refereegranskat)abstract
- Traditional intensity modulated two-level electrical time-division multiplexing (ETDM) transmission systems working at 100-112 Gbit/s were investigated. The complete ETDM systems based on monolithically integrated transmitter and receiver modules were demonstrated with bit-error-rate (BER) performance of 10-8 at 107 Gbit/s, and near error-free standard forward error correction (FEC) threshold (2×10-3) at 112 Gbit/s. The experiment results showed that directly modulated high-speed ETDM transmission systems with the symbol rates at 100 Gbaud and beyond were promising candidate for cost-effective 100 GbE applications and might be a preform of the next generation of Terabit/s Ethernet.
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| 3. |
- Kellock, H., et al.
(författare)
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Higher-order ghost imaging with partially polarized classical light
- 2011
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Ingår i: Proc SPIE Int Soc Opt Eng. - : SPIE. - 9780819487971
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Konferensbidrag (refereegranskat)abstract
- Visibility, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) are quantities that characterize the quality of the image in ghost (or correlation) imaging. The visibility in quantum and classical ghost imaging with scalar light is known to improve as the order of imaging increases. Recently also electromagnetic ghost imaging has started to attract attention. In this work we analyze the effects of both the order of imaging and the degree of polarization (P) of the illumination on the image quality parameters. The source is a classical, partially polarized, random electromagnetic field obeying Gaussian statistics. The beam is split into several (N) parts which are directed either into the object or reference arms and the associated intensity correlations are calculated. When N > 2, more than one reference arm may exist which contributes to the background. We consider two different definitions for the visibility, as well as the SNR and CNR, and examine their attainable limiting values in second- and higher-order ghost imaging as a function of the degree of polarization. Both expressions of the visibility behave in a similar manner; they increase with the order of imaging and the degree of polarization. In second-order imaging the SNR decreases, due to increased noise, as P increases, while the CNR remains essentially constant. We emphasize that the exact numerical values depend on the definitions used and on the number of object arms in the setup.
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| 4. |
- Kellock, H., et al.
(författare)
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Temporal double- and triple-intensity correlation imaging with classical light
- 2010
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Ingår i: 2010 9th Euro-American Workshop on Information Optics, WIO 2010. - 9781424482276 ; , s. 5582500-
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Konferensbidrag (refereegranskat)abstract
- The second- and third-order temporal ghost imaging setups with classical light are discussed. The second-order scheme has a single reference arm with a temporal lens and dispersive elements, and an object arm containing an object surrounded by dispersive media. The third-order imaging setup contains two reference arms instead of one. Both setups have a temporally completely incoherent light source providing maximum resolution. The dependence of visibility and resolution of the images on system parameters is considered in both setups.
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| 5. |
- Moya-Cessa, H., et al.
(författare)
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Degree of polarization and quantum-mechanical purity
- 2008
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Ingår i: Journal of the European Optical Society-Rapid Publications. - : European Optical Society. - 1990-2573. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- The purity parameter is used in quantum mechanics to discriminate pure states from mixed states. We employ this concept to define a degree of polarization for general, three-dimensional, classical random electric fields. Our approach leads to a result that is identical with a recent definition obtained by a decomposition of the polarization matrix in terms of the Gell-Mann matrices. We also give an expression for this degree of polarization based on the constituent two-dimensional subsystems. [DOI: 10.2971/jeos.2008.08014]
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| 6. |
- Rinman, M-L, et al.
(författare)
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EPS - an interactive collaborative game using non-verbal communication
- 2003
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Ingår i: Proceedings of the Stockholm Music Acoustics Conference, August 6-9, 2003 (SMAC 03), Stockholm, Sweden. ; , s. 561-563
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Konferensbidrag (refereegranskat)abstract
- The interactive game environment EPS (expressive performance space), presented in this short paper, is a work still in progress. EPS involves participants in an activity using non-verbal emotional expressions. Two teams use expressive gestures in either voice or body movements to compete. Each team has an avatar controlled either by singing into a microphone or by moving in front of a video camera. Participants/players control their avatars by using acoustical or motion cues. The avatar is navigated /moving around in a 3D distributed virtual environment using the Octagon server and player system. The voice input is processed using a musical cue analysis module yielding performance variables such as tempo, sound level and articulation as well as an emotional prediction. Similarly, movements captured from the video camera are analyzed in terms of different movement cues. The target group is children aged 13- 16 and the purpose is to elaborate new forms of collaboration.
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| 7. |
- Setala, T., et al.
(författare)
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Evanescent and propagating electromagnetic fields in scattering from point-dipole structures
- 2001
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Ingår i: Journal of the Optical Society of America A. - 0740-3232. ; 18:3, s. 678-688
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the propagating and evanescent field contributions in the scattering of an electromagnetic field from a collection of interacting electric point dipoles. Having applications of scanning near-field optical microscopy (SNOM) in mind, we study three different geometries of dipoles placed close to a bulk surface. One of them is chosen to allow a direct comparison with the results recently put forward in the literature [J. Mod. Opt. 44, 327 (1997)] and to point out the discrepancies in the near zone between the held decompositions applied in that paper and in our work. The other two geometries have been selected to illustrate SNOM action in the illumination and collection modes. Within the point-dipole model we investigate the effects of the probe-dipole polarization on the propagating and evanescent fields in the sample-probe system during the scanning of the probe at different heights above the sample.
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| 8. |
- Shirai, T., et al.
(författare)
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Classical ghost diffraction enabling aberration-corrected imaging
- 2012
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Ingår i: Frontiers in Optics, FIO 2012. - 9781557529565
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Konferensbidrag (refereegranskat)abstract
- We describe a method for image transmission through an aberrating medium by means of a modified configuration for conventional ghost diffraction with classical incoherent beams and show theoretically that the method enables aberration-corrected imaging.
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| 9. |
- Shirai, T., et al.
(författare)
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Fourier synthesis in classical ghost imaging
- 2011
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Ingår i: Proceedings of Applied Industrial Optics: Spectroscopy, Imaging and Metrology, AIO 2011. - : The Optical Society. - 9781557529145
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Konferensbidrag (refereegranskat)abstract
- We describe an optical setup for performing spatial Fourier filtering in ghost imaging with classical incoherent light. It is shown that phase contrast imaging is possible with this setup to visualize a pure phase object.
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| 10. |
- Torres-Company, V., et al.
(författare)
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'Nonlocal' dispersion cancelation with classical light
- 2009
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- We show a classical analog of the original nonlocal dispersion cancelation effect in intensity interferometry with stationary light obeying Gaussian statistics. The dispersion compensation is due to the uncorrelation of the spectral components of the radiation. Although this classical counterpart phenomenon is not nonlocal in a strict quantum mechanical sense, it suggests that some second-order interference devices relying on temporal entanglement do not require a quantum light source.
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