| 1. |
- Ablikim, M., et al.
(författare)
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Measurements of (XcJ)-> K+K-K+K- decays
- 2006
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 642:3, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- Using 14M psi(2S) events taken with the BESII detector, chi(cJ) -> 2(K+K-) decays are studied. For the four-kaon final state, the branching fractions are B(chi(c0,1,2) ->.2(K+K-)) = (3.48 +/- 0.23 +/- 0.47) x 10(-3), (0.70 +/- 0.13 +/- 0.10) x 10(-3), and (2.17 +/- 0.20 +/- 0.31) x 10(-3). For the phi K+K- final state, the branching fractions, which are measured for the first time, are B(chi(c0,1,2) -> phi K+K-) = (1.03 +/- 0.22 +/- 0.15) x 10(-3), (0.46 +/- 0.16 +/- 0.06) x 10(-3), and (1.67 +/- 0.26 +/- 0.24) x 10(-4). For the phi phi final state, B(chi(c0,2) -> phi phi) = (0.94 +/- 0.21 +/- 0.13) x 10(-3) and (1.70 +/- 0.30 +/- 0.25) x 10(-3).
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| 2. |
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| 3. |
- Höglund, Linda, 1974-, et al.
(författare)
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Quantum dots-in-a-well infrared photodetectors for long wavelength infrared detection
- 2006
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Ingår i: Proceedings of SPIE. - Bellingham, Wash. : SPIE - International Society for Optical Engineering. - 9780819464996 ; 6401, s. 1-640109
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Konferensbidrag (refereegranskat)abstract
- We report on a quantum dots-in-a-well infrared photodetector (DWELL QDIP) grown by metal organic vapor phase epitaxy. The DWELL QDIP consisted of ten stacked InAs/In0.5Ga0.85As/GaAs QD layers embedded between n-doped contact layers. The density of the QDs was about 9 × 10 10 cm-2 per QD layer. The energy level structure of the DWELL was revealed by optical measurements of interband transitions, and from a comparison with this energy level scheme the origin of the photocurrent peaks could be identified. The main intersubband transition contributing to the photocurrent was associated with the quantum dot ground state to the quantum well excited state transition. The performance of the DWELL QDIPs was evaluated regarding responsivity and dark current for temperatures between 15 K and 77 K. The photocurrent spectrum was dominated by a LWIR peak, with a peak wavelength at 8.4 μm and a full width at half maximum (FWHM) of 1.1 μm. At an operating temperature of 65 K, the peak responsivity was 30 mA/W at an applied bias of 4 V and the dark current was 1.2×10-5 A/cm2. Wavelength tuning from 8.4 μm to 9.5 μm was demonstrated, by reversing the bias of the detector.
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| 4. |
- Junique, Stephane, et al.
(författare)
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A Modulating retro-reflector for free-space optical communication
- 2006
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 18:1, s. 85-87
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Tidskriftsartikel (refereegranskat)abstract
- We present modeling of a modulating retro-reflector for free-space optical communication, composed of a reflective resonant-cavity modulator and a corner cube. Although resonant-cavity modulators are sensitive to the angle of incidence of the light beam, we show that with the right geometrical arrangement, the field of view can be more than ten-fold that of the modulator. The modeling is validated by experimental data using a corner cube and a 14 x 14 mm(2) multiple quantum-well modulator.
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| 5. |
- Wang, Qin, et al.
(författare)
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1550 nm transmissive/reflective surface-normal electroabsorption modulator arrays
- 2006
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Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 42:1, s. 47-48
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Tidskriftsartikel (refereegranskat)abstract
- Arrays of surface-normal 1550 nm transmissive/reflective dual-function electroabsorption modulators based oil InGaAs/InAlAs coupled quantum wells are investigated for free-space and optical fibre communications. The modulators can readily be switched between transmissive or reflective mode by using a removable Au mirror, which provides flexibility in the optical system configuration for different applications. The modulators exhibit contrast ratio of 2:1 at 3 V driving bias and contrast ratio of 2:1 over 30 nm bandwidth at 6 V. The maximum contrast ratio of 4:1 is achieved at a 12 V driving voltage.
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| 6. |
- Zody, Michael, 1968-, et al.
(författare)
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Analysis of the DNA sequence and duplication history of human chromosome 15
- 2006
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 440:7084, s. 671-675
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Tidskriftsartikel (refereegranskat)abstract
- Here we present a finished sequence of human chromosome 15, together with a high-quality gene catalogue. As chromosome 15 is one of seven human chromosomes with a high rate of segmental duplication, we have carried out a detailed analysis of the duplication structure of the chromosome. Segmental duplication in chromosome 15 are largely clustered in two regions, on proximal and distal 15q; the proximal region is notable because recombination among the segmental duplications can result in deletions causing Prader-Willi and Angelman syndromes. Sequence analysis shows that the proximal and distal regions of 15q share extensive ancient similarity. Using a simple approach, we have been able to reconstruct many of the events by which the current duplication structure arose. We find that most of the intrachromosomal duplications seem to share a common ancestry. Finally, we demonstrate that some remaining gaps in the genome sequence are probably due to structural polymorphisms between haplotypes; this may explain a significant fraction of the gaps remaining in the human genome.
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