| 1. |
- Broussalis, Adriana M., et al.
(författare)
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First cyclotide from Hybanthus (Violaceae)
- 2001
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Ingår i: Phytochemistry. - : Elsevier. - 0031-9422 .- 1873-3700. ; 58:1, s. 47-51
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Tidskriftsartikel (refereegranskat)abstract
- Hypa A, a novel macrocyclic polypeptide containing 30 amino acid residues, has been isolated from the n-butanol extract of the Argentine plant Hybanthus parviflorus. The sequence, cyclo-(SCVYIPCTITALLGCSCKNKVCYNGIPCAE), was determined by automated Edman degradation, quantitative amino acid analysis and nanospray MS/MS2. Three intramolecular disulfide bridges stabilize the cyclic peptide backbone of hypa A. Using these structural features to classify the peptide as a cyclotide, we extended the distribution of that substance class to a new genus, and now propose a uniform nomenclature for cyclotides.
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| 2. |
- Grilli, Simonettta, et al.
(författare)
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In-situ visualization, monitoring and analysis of electric field domain reversal process in ferroelectric crystals by digital holography
- 2004
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Ingår i: Optics express. - 1094-4087. ; 12:9, s. 1832-1842
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Tidskriftsartikel (refereegranskat)abstract
- In-situ monitoring of domain reversal in congruent lithium niobate by a digital holographic technique is described. While the ferroelectric polarization is reversed by electric field poling, the two-dimensional distribution of the phase shift, due mainly to the linear electro-optic and piezoelectric effects, is measured and visualized. Digital holography is used to reconstruct both amplitude and phase of the wavefield transmitted by the sample to reveal the phase shift induced by adjacent reversed domains during the poling. The resulting movies of both amplitude and phase maps, for in-situ visualization of domain pattern formation, are shown. The possibility of using the technique as tool for monitoring in real-time the periodic poling of patterned samples is discussed.
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| 3. |
- Grilli, Simonetta, et al.
(författare)
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Visualization of optical deflection and switching operations by a domain-engineered-based LiNbO electro-optic device
- 2003
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Ingår i: Optics express. - 1094-4087. ; 11, s. 1212-
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Tidskriftsartikel (refereegranskat)abstract
- An electro-optic device applied as an optical beam deflector and switch at different wavelengths has been built and tested. The electro-optic device is based on domain-engineered lithium niobate (LiNbO3). In this paper, for the first time, its operation has been visualized by an imaging camera. The device has been characterized both at the visible wavelength (632.8 nm) and at a typical telecom wavelength (1532 nm). Furthermore, the device has been tested as an amplitude modulator in the mid-infrared region as well, at a wavelength of similar to4.3 mum, where no Pockels cells are available. A detailed description of this device is given, and the experimental results are discussed.
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| 4. |
- Paturzo, M., et al.
(författare)
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Investigation of electric internal field in congruent LiNbO3 by electro-optic effect
- 2004
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Ingår i: Applied physics letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 85, s. 5652-5654
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the effect of the defect-induced internal field on the electro-optic behavior of z-cut congruent lithium niobate crystals. We measure, by a spatially resolved interferometric technique, the phase retardation due to an external applied voltage occurring in two regions with opposite ferroelectric polarization. When measurements are performed just after electrical poling, the two opposite domains show a different electro-optic behavior. We interpret this as due to an elastic component of the internal field. In fact, the asymmetric behavior disappears when the sample is thermally annealed, i.e., when the internal field vanishes
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