Carboxylate ions and nordstrandite growth: AFM surface observations
Notice bibliographique
Résumé
The aluminum hydroxide minerals are important in the production of aluminium, the regulation of aluminum in natural waters and the adsorption of ions. The polymorphs of Al(OH)3 (gibbsite, nordstrandite, doyleite) differ in terms of the stacking of their unit layers. Nordstrandite occurs in many soils and has industrial uses. The presence of carboxylate ions in solution during crystal growth causes nordstrandite crystals to be less well-formed in overall appearance, compared to when grown without the presence of the carboxylate ions. In order to gain more understanding of the effects of carboxylate ions on Al(OH)3 growth, atomic force microscopy (AFM) was used to observe the nanometer scale surface morphology of nordstrandite crystals synthesized from Al metal in ethylenediamine solutions in the presence of malonate, aspartate, oxalate and citrate ions. The AFM images showed that crystal faces were smoother overall for the nordstrandite crystals synthesized without carboxylate ions. For crystals synthesized in solutions with the largest concentrations of carboxylate ions, the nanometer scale images showed that the surfaces were very irregular and were characterized by elongated islands. Our AFM observations were the same for nordstrandite samples grown with large differences in the amount of stirring of the crystallizing solutions, indicating that the effect of bulk diffusion alone could not have been responsible for the effect of the carboxylate ions on crystal growth. Moreover, only a weak correlation existed between the concentration of carboxylate ions in the crystallizing solution and the amount of nordstrandite produced. On the {110} basal faces of the nordstrandite crystals, which are oriented parallel to the stacking of the unit layers, steps having a height of one nordstrandite unit layer were observed. 2dimensional growth was primarily observed on these faces. For the nordstrandite crystals synthesized without carboxylate ions, the steps were oriented along crystallographic directions, and extended all or most of the way across the crystal faces. Many of these steps were parallel to each other. The nucleation of new terraces occurred primarily at the edges of the crystal faces, and few if any islands nucleated in the centres of the faces. The crystals synthesized with the highest concentrations of carboxylate ions had steps on the basal surfaces that were more rounded and conformed less to the crystallographic directions. The carboxylate ions also promoted the nucleation of small monolayer islands in the interiors of the crystal faces. Melt-rock reaction in Canadian Cordillera mantle xenoliths A.H. PESLIER, A.D.BRANDON, D.FRANCIS AND J. LUDDEN Texas Center for Superconductivity, University of Houston, Houston, TX 77204, USA (apeslier@mail.uh.edu) NASA-JSC, Mail Code SR, Bdg. 31, Room 114, Houston, TX 77058, USA (alan.d.brandon1@jsc.nasa.gov) Dpt. of Earth and Planetary Sciences, McGill University, Montreal, QC H3A 2A7, Canada (don_f@eps.mcgill.ca) Centre de Recherches Petrographiques et Geochimiques, B.P.20, 54501 Vandoeuvre-les-Nancy, France (ludden@crpg.cnrs-nancy.fr)
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».