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Factors affecting the measurement of photochromic lens performance / Liu Ouyang in COLORATION TECHNOLOGY, Vol. 132, N° 3 (06/2016)
[article]
Titre : Factors affecting the measurement of photochromic lens performance Type de document : texte imprimé Auteurs : Liu Ouyang, Auteur ; Hongliang Huang, Auteur ; Yong Tian, Auteur ; Wei Peng, Auteur ; Huanbao Sun, Auteur ; Weizhong Jiang, Auteur Année de publication : 2016 Article en page(s) : p. 238-248 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Lentilles (optique)
Mesure
PhotochromismeIndex. décimale : 535.33 Instruments d'optique : classer à 681.4 Résumé : The principles, characteristics, and measurement methodology of photochromism of plastic ophthalmic lenses are briefly introduced and discussed. The factors influencing measurement variation and accuracy, including the preconditioning process, measurement device, and procedure, were investigated on ophthalmic photochromic lenses covering both photocasting and photocoating lens technologies. By design of experiment, factors affecting the measurements were studied using a photochromic measurement rig with reference to ISO 8980-3 requirements. Experimental results prove the necessity for a lens preconditioning process prior to measurement. The excitation light source in the photochromic measurement rig has the greatest impact on measurement variation from the device perspective, while lens temperature is the key environmental factor. On the basis of the investigation, recommendations are made for reducing measurement variations and improving result accuracy. Note de contenu : - EXPERIMENTAL : Materials - Measurements - Experiments
- RESULTS AND DISCUSSION : PMR stability and lens performance uniformity - Lens geometry - Lens preconditioning - Measurements conditions - Other factorsDOI : 10.1111/cote.12214 En ligne : https://drive.google.com/file/d/1CA-86eJTWzKcH4C8Yuj1a8eTPmU1VxXU/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26356
in COLORATION TECHNOLOGY > Vol. 132, N° 3 (06/2016) . - p. 238-248[article]Réservation
Réserver ce documentStudies of structure changes of archeological leather by FTIR spectroscopy / Yang Zhang in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC), Vol. 102, N° 5 (09-10/2018)
[article]
Titre : Studies of structure changes of archeological leather by FTIR spectroscopy Type de document : texte imprimé Auteurs : Yang Zhang, Auteur ; Zifan Chen, Auteur ; Chengming Wang, Auteur ; Yong Tian, Auteur ; Decai Gong, Auteur Année de publication : 2018 Article en page(s) : p. 262-267 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Antiquités (objets anciens) -- Analyse
Collagène -- Détérioration
Cuirs et peaux -- Analyse
Cuirs et peaux -- Détérioration
Essais accélérés (technologie)
Fourier, Spectroscopie infrarouge à transformée de
Tanins végétaux
Tannage végétalIndex. décimale : 675 Technologie du cuir et de la fourrure Résumé : Fourier transform infrared spectroscopy was used to investigate protein structures in new vegetable-tanned and artificially aged leather as well as in waterlogged archaeological leather dating from the Warring State Period (475BC-221BC). The obtained quantitative and qualitative information on protein structure changes was useful to characterize the deterioration of the archaeological leather during ageing in the buried environment. Compared with those in new vegetable-tanned leather, the amide A and amide II bands in the artificially aged and archaeological leather shifted to lower wavenumbers, suggesting hydrogen bonding in the collagen in the artificially and naturally aged leather was weakened. The estimation of the relative percentages of collagen secondary structures based on the peak area of component bands in the amide III showed that a-helix structure of collagen convertet into a random coil structure in the artificially aged and archaeological leather. Besides, the characteristic absorption peaks of tannins appeared in the spectra of all archaeological leather samples, but the tannins content decreased, indicating that tannins present in the archaeological leather could be degraded or detanned. The results showed that there was an increase in disorder structures in the collagen molecular structure and that the crosslinking between the tannins and collagen was disrupted in archaeological leather. This study will help us to elucidate the deterioration mechanism and guide the conservation of archaeological leathers. Note de contenu : - EXPERIMENTAL PROCEDURES : Samples - Accelerated ageing measurements - Instrumentation
- RESULTS AND DISCUSSION : Analysis of FTIR spectra - Changes in collagen secondary structures - Degradation of vegetable tannins
- Fig. 1 : FTIR spectra of new, artificially aged and archaeological leathers
- Fig. 2 : Amide III curve-fitting spectra new vegetable-tanned leather, artificially aged leather, old 1 sqample, old 2 sample, old 3 sample
- Fig. 3 : Comparison of the relative amount of secondary structures in amide III
- Table 1 : FTIR spectra peak positions and assignments
- Table 2 : Δv(vAl-vAll) and IR absorption ratio 1239/1450 cm-1
- Table 3 : Assignments and relative amounts of secondary structures in amide IIIEn ligne : https://drive.google.com/file/d/182gmLMtHUQgbH95e42H2-UOWa1aB22-_/view?usp=drive [...] Format de la ressource électronique : Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31113
in JOURNAL OF THE SOCIETY OF LEATHER TECHNOLOGISTS & CHEMISTS (JSLTC) > Vol. 102, N° 5 (09-10/2018) . - p. 262-267[article]Réservation
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