| 1. |
- Zhang, J. G., et al.
(författare)
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Microstructure and mechanical properties of spray formed ultrahigh-carbon steels
- 2004
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Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5093 .- 1873-4936. ; 383:1, s. 45-49
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Tidskriftsartikel (refereegranskat)abstract
- The microstructure and mechanical properties of the spray formed 1.25C-3.0Si-1.5Cr ultrahigh-carbon steel (UHCS) were described. The 1.25C-3.0Si-1.5Cr UHCS was processed by spray forming to break up carbide networks. The fine pearlites with average interlamellar spacing of 0.20 mum was observed in the as-sprayed microstructure. The ultimate tensile strength and the pearlite spacing can be related by the Hall-Petch equation. The as-sprayed 1.25C-3.0Si-1.5Cr UHCS consisting of fine lamellar pearlites has been shown to exhibit superplastic behavior at elevated temperature. The dramatic change of microstructure from fine lamellar pearlites to equiaxed grains stabilized by spheroidized particles during superplastic deformation has been observed. The estimation on the basis of thermodynamics shows that the content of chromium of 1.54 wt.% is needed to inhibit graphite formation in the l.25C-3.OSi-1.5Cr UHCS.
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| 2. |
- Huang, Z. L., et al.
(författare)
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Novel heterocycle-based organic molecules with two-photon induced blue fluorescent emission
- 2003
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Ingår i: Journal of Materials Chemistry. - : Royal Society of Chemistry (RSC). - 0959-9428 .- 1364-5501. ; 13:4, s. 708-711
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Tidskriftsartikel (refereegranskat)abstract
- Two-photon absorption and two-photon induced blue emission characteristics of a series of heterocycle-based organic molecules are investigated experimentally and by quantum-chemical computations. The molecules consist of a typical A-pi-A' structure, where heterocycle, styryl and formyl groups are employed as A, pi-conjugated and A' moieties, respectively. Experimental results indicate that significant enhancements in the blue emission efficiency and two-photon absorption cross-sections can be achieved by replacing S and O atoms with an N atom in the heterocycle acceptor moiety, which is also supported by the quantum-chemical computations. Additionally, larger two-photon absorption cross-sections can be obtained by choosing appropriate solvents, as indicated by the computations.
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| 3. |
- Luo, X, et al.
(författare)
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RFI suppression in ultra-wideband SAR systems using LMS filters in frequency domain
- 2001
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Ingår i: Electronics Letters. - 0013-5194 .- 1350-911X. ; 37:4, s. 241-243
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Tidskriftsartikel (refereegranskat)abstract
- A least-mean-square algorithm in the frequency domain, with amplitude normalisation. is proposed to remove narrowband radio frequency interference in low-frequency ultra-wideband synthetic aperture radar systems. The performance uf the algorithm was tested on experimental data acquired with the CARABAS system.
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