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1
Doyle, Kathryn. "Stabilization of β-cristobalite in the SiO2-AlPO4-BPO4 system". Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1610107429523976.
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Ouammou, Mohamed. "Synthèse hydrothermale de AlPO4 en milieux acides mixtes, HCl-H2SO4-H3PO4." Montpellier 2, 1988. http://www.theses.fr/1988MON20150.
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Etude de la solubilite de la berlinite (alpo::(4)) dans des melanges binaires et ternaires d'hcl, de h::(3)po::(4) et de h::(2)so::(4). Synthese hydrothermale de cristaux de phosphate d'aluminium. Caracterisation par la spectrometrie ir et examen au miscrope electronique a balayage. Etude de la piezoelectricite
3
Bentama, Jilali. "Cristallogénèse et propriétés physiques de la berlinite (AlPO4) élaborée en milieu chlorhydrique." Montpellier 2, 1987. http://www.theses.fr/1987MON20135.
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Determination de la solubilite de alpo::(4) dans hcl et recherche du domaine experimental de cristallogenese du materiau dans ce milieu par voie hydrothermale. Etude de l'influence de certains parametres (concentration de l'acide, temperature de cristallisation, nature des lames. . . ) sur la cinetique de croissance. Caracterisation des cristaux par microscopie optique et electronique a balayage. Determination de la qualite cristalline par topographie rx et absorption ir. Caracterisation piezoelectrique. Resultats obtenus par analyse thermique differentielle a balayage (dsc et atd) sur des solutions solides de alpo::(4)
4
Ye, Jianting. "Fabrication and optical characterization of nanostructures formed inside AlPO4-5 zeolite single crystals /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202006%20YE.
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Bennazha, Jamal. "Etude du système GaPO4 - AlPO4 : cristallogénèse et caractérisation des phases Al(1-x)GaxPO4 et GaPO4." Montpellier 2, 1991. http://www.theses.fr/1991MON20160.
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Ce travail porte sur l'etude du systeme gapo#4-alpo#4. Une solution solide continue a ete mise en evidence dans tout le domaine de composition etudie et a ete caracterisee par diffraction des rayons x. Apres avoir precise l'evolution de la temperature de transition - nous avons entrepris la mise au point de la cristallogenese des phases al#(#1##x#)ga#xpo#4 et gapo#4, a solubilite retrograde par des methodes de montee lente en temperature et du gradient vertical de temperature
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Boulogne, Bruno. "Etude par microscopie électronique en transmission et spectroscopie infrarouge des défauts de réseau dans la berlinite AlPO4." Lille 1, 1987. http://www.theses.fr/1987LIL10221.
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Caractérisation du contenu en eau des cristaux de berlinite obtenus par voie hydrothermale, et mise en évidence de l'influence de l'eau sur les propriétés mécaniques. Caractérisation des défauts étendus et des dislocations mobiles dans AlPO4 par microscopie électronique en transmission et influence de l'eau sur la mobilité des dislocations
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Goepper, Michèle. "Synthèse et caractérisation de tamis moléculaire du type AlPO4 substitués par les éléments divalents Mg, Co ou Zn." Mulhouse, 1990. http://www.theses.fr/1990MULH0152.
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Au cours des dix dernières années de nombreuses familles de nouveaux solides microporeux ont été signalées dans la littérature. Certains de ces tamis moléculaires présentent une topologie de charpente analogue à celle des zéolithes naturelles, d'autres ont une structure nouvelle. Ce travail de thèse comprend la synthèse hydrothermale de solides microporeux basé sur une charpente aluminophosphate. Nous avons, en particulier, étudié l'incorporation de métaux (Me=Mg, Co ou Zn) à l'intérieur de cette charpente, ceci dans le but de modifier les propriétés échangeuses d'ions de ces matériaux. La caractérisation des échantillons préparés est également une partie très importante de notre travail. Grâce aux techniques de diffraction des RX, à la RMN haute résolution des noyaux 27Al et 31P sur les solides et à la réflexion diffuse UV-visible nous avons vérifié l'incorporation des métaux dans les sites de l'aluminium. Ces techniques nous ont également permis de suivre les modifications structurales qui apparaissent lorsque les échantillons sont calcinés
8
Menges, Markus [Verfasser], and B. [Akademischer Betreuer] Kraushaar-Czarnetzki. "Untersuchungen zum MTO-Prozess an AlPO4-gebundenen ZSM-5-Extrudaten und Beschreibung der Reaktionskinetik / Markus Menges ; Betreuer: B. Kraushaar-Czarnetzki." Karlsruhe : KIT Scientific Publishing, 2012. http://d-nb.info/1184492263/34.
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Deroche, Christiane. "Experimentelle und rechnerische Analyse des Einbaus von Sorbatmolekülen in die Wirtsstrukturen der 12-Ring-Kanalsysteme ZSM-12 (MTW) und AlPO4-5 (AFI)." [S.l. : s.n.], 1999. http://deposit.ddb.de/cgi-bin/dokserv?idn=966143795.
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Cambon, Olivier. "Etude de systèmes solution/soluté au voisinage de l'équilibre : croissance et dissolution : application à la dissolution contrôlée d'un matériau piézoélectrique, la berlinite (AlPO4)." Montpellier 2, 1990. http://www.theses.fr/1990MON20261.
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La berlinite (alpo#4) est un materiau piezoelectrique qui presente toutes les qualites requises pour la realisation de dispositifs de filtrage. Dans le cas du radiotelephone, les deux frequences d'utilisation (45 et 70 mhz) correspondent a des epaisseurs de lame tres faibles (20 microns pour 70 mhz). La technique d'usinage doit permettre d'atteindre de telles epaisseurs tout en generant un bon etat de surface. Nous avons envisage l'usinage chimique qui est une methode atraumatique et peu onereuse. Les solvants les plus utilises ont ete les acides phosphorique et sulfurique. Une loi de vitesse a alors ete determinee pour la dissolution en milieu acide. Un mecanisme de dissolution de la berlinite a ete propose. L'apparition rapide de defauts de surface nous a amenes a considerer la theorie thermodynamique de croissance ou de dissolution qui montre que pour obtenir un bon controle de la croissance ou de la dissolution, l'ecart a l'equilibre doit etre faible. Les solutions ont alors ete enrichies en phosphate d'aluminium. Les mesures de rugosite ont montre une nette amelioration de l'etat de surface et meme une disparition totale des defauts. Enfin, les echantillons ainsi elabores ont pu etre caracterises par des mesures piezoelectriques qui ont montre une qualite d'usinage suffisante pour une application industrielle
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Aubert, Emmanuel. "Etude des interactions de molécules hôtes dans des zéolithes synthétiques par diffraction des rayons X à haute résolution." Phd thesis, Université Henri Poincaré - Nancy I, 2003. http://tel.archives-ouvertes.fr/tel-00142220.
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Les zéolithes sont des solides cristallins caractérisés par l'existence de canaux pouvant accueillir des ions et molécules hôtes. Ces matériaux sont donc utilisés dans de nombreux procédés physico-chimiques, tels que la séparation moléculaire, la catalyse, l'échange cationique, et plus récemment comme constituant de nouveaux matériaux composites. Dans ce travail nous nous sommes intéressés à la caractérisation des interactions dans les tamis moléculaires de type MFI, AFI et AlPO4-15 via la diffraction des rayons X à haute résolution sur monocristal et la thermogravimétrie et calorimétrie.<br /> Les monocristaux nécessaires ont été obtenus au laboratoire par synthèse hydrothermale. L'étude de la densité de charge de AlPO4-15 a révélé les interactions hôte / invité dans ce composé et, avec l'analyse de sa topologie, a permis d'en modéliser le potentiel électrostatique. L'étude de la zéolithe MFI a permis de localiser l'ion fluorure qui se trouve être lié à un atome de silicium de la charpente.
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Hussmann, Frauke. "Regulation of S. pombe microtubule dynamics by Alp14, Alp7 and Dis1." Thesis, Institute of Cancer Research (University Of London), 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551112.
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TOG-family polymerases track microtubule plus ends and modulate dynamics in vivo. In vitro XMAP215 and Stu2 have been shown to exhibit opposing activities, which led to conflicting proposals for molecular mechanisms. To understand more about these apparently contradictory findings and to test candidate models in more detail, I used an in vitro system in which all the components derived from the same organism, Sacchammyce pombe. Deletion mutants of Alp14 and Dis1, the XMAP215 orthologues in S. pombe, show defects in microtubule assembly, consistent with an effect on microtubule dynamics. I have expressed and purified Alp14 and Disl and the TACC-protein Alp7 using a baculovirus system and reconstituted their activities in vitro using dynamically unstable single micro tubules built from purified single isoform (cd and (3)) S. pombe tubulin. In this work I show that Alp14 accelerates the shrinkage of GMP-CPP stabilized microtubules 2x while it accelerates the assembly of GTP-S. pombe tubulin into micro- tubules J Ox. Growth rates change within a growth phase, corresponding to different amounts of Alp14 at the tip. The growth rate acceleration by Alp14 causes a decrease in catastrophe frequency consistent with the extension of the GTP-cap. Remark- ably, although Alp14 binds to mammalian brain tubulin, it does not accelerate the growth rate of mammalian brain micro tubules, and instead is competitively inhibited by 10% mammalian brain tubulin, indicating a catalytic mechanism for Alp14. Catalytic activity and tip tracking are tightly coupled, but separable. Alp14 loses its tip tracking ability upon the addition of 10% mammalian brain tubulin. The TACC-protein Alp7 can restore the tip-tracking ability of Alp14 in the presence of mammalian brain tubulin but not its activity, consistent with reports that Alp7 is a localization factor of AJp14 in vivo. On dynamic S. pombe microtubules Alp7 increases the processivity of Alp14 and suppresses the catastrophe frequency. Growth rates are not further elevated by the addition of Alp7. In contrast, Disl has no TACC-protein interacting partner. Like Alp14 it disassembles GMP-CPP microtubules and increases the growth rate of S. pombe microtubules. Likewise it binds to mammalian brain tubulin without the ability to increase the growth rate of mammalian brain microtubules. However, unlike Alp14, Dis1 is able to tip-track on dynamic mammalian brain microtubules. As both Alp14 and Disl function as S. pombe microtubule polymerases, but not as mammalian brain microtubule polymerases, I concluded that not only the association of tubulin to XMA P215-family members is important for proper function but also that the ready dissociation of tubulin is just as important. Slow dissociation inhibits the activity of XMAP215-family member, supporting a catalytic model. Furthermore I found that higher affinity to the microtubule lattice did not enhance the catalytic activity of Alp14. Instead the higher affinity to the microtubule lattice of Alp14 in the presence of Alp7 increased the residence time of Alp14 at the tip. In return this decreased the catastrophe frequency, enhancing the effectiveness of Alp14 as a polymerase at the microtubule tip. Disl possesses an intrinsic high affinity to the microtubule lattice, tracking the microtubule end readily, but does not exhibit higher polymerase activity than Alp14. On the basis of these data, I propose an assembler model for the molecular mechanism of Alp14-Alp7 and Dis l , in which both XMAP215- family members enhance the growth rate of S. pombe microtubules by accelerating the exchange reaction of GTP-tubulin. High processivity and in return high effectiveness of the catalysts are mediated by Alp7 in the case of Alp14 and by internal microtubule lattice binding regions in the case of Disl.
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Appapillai, Anjuli T. (Anjuli Tara). "Electrochemical and microstructural studies of AlPO₄-nanoparticle coated LiCoO₂ for lithium-ion batteries." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36195.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.<br>Includes bibliographical references (p. 101-108).<br>AlPO₄-nanoparticle coated LiCoO₂ is studied as a positive electrode for lithium rechargeable batteries for a high-voltage charge limit of 4.7V. To understand the role of the coating in transport phenomena and in deintercalation of Li+, the electrochemical behavior is studied alongside the microstructure of the coating. The galvanostatic charge profile is studied with electrochemical impedance tests conducted at various lithium contents during charging. The coating is found to increase the flatness of the two-phase region plateau and to cause the appearance of the monoclinic distortion at x=0.5 as well as distinct plateaus for 03 to H1-3 and H1-3 to 01 transitions, indicating that application of the coating transformed Li-rich LiCoO₂ into stoichiometric LiCoO₂. According to electronic resistance (Re) values from impedance spectra, the coated LiCoO₂ has a more rapid decrease in Re with delithiation, and both materials show a rise in Re above 4.5V. Structurally, SEM images show pitted surface morphology only on the edges of the layers of coated LiCoO₂.<br>(cont.) Furthermore, cross-sectional TEM images reveal a continuous coating layer with compositional variations seen through EDX mapping and point spectroscopy, indicating that a thin layer of aluminum covers the particle uniformly while the phosphorus is more concentrated in thicker, isolated clusters, which is further supported y XPS surface analysis. This coating composition may increase the ionic conductivity of the LiCoO₂ surface while protecting it from harmful side reactions and stabilizing the surface structure to inhibit Co dissolution.<br>by Anjuli T. Appapillai.<br>S.M.
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Magneron, Nathalie. "Approche multi-echelle de alpo#4 : etude par spectroscopies brillouin, infrarouge et rmn." Orléans, 1998. http://www.theses.fr/1998ORLE2052.
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Le phosphate d'aluminium alpo#4, compose presentant la meme richesse structurale que sio#2 (memes varietes cristallines : quartz, cristobalite, tridymite, chacune presentant deux phases, existence d'une structure incommensurable), a ete utilise pour une etude a differentes echelles spatiales (des dimensions de l'objet de base, le tetraedre, jusqu'a des distances beaucoup plus grandes, de l'ordre de quelques milliers de distances interatomiques). Cette approche multi-echelle a ete effectuee en utilisant trois spectroscopies : la rmn, la reflexion infrarouge et la diffusion brillouin. L'etude par rmn des noyaux #3#1p, #7#1ga et #2#7al a permis de preciser la connaissance de l'environnement local et des domaines de stabilite dans les systemes alpo#4 et gapo#4. Cette etude a ete elargie aux varietes amorphes dans des systemes mixtes. Les modes optiques de vibration de alpo#4 ont ete etudies par reflectivite infrarouge permettant la determination des charges effectives et le suivi de leur evolution jusqu'a la temperature de fusion. La spectroscopie brillouin a mis en evidence une dynamique fortement anharmonique des modes acoustiques resultant, a l'echelle sondee, d'un effet global des liaisons chimiques non accessible directement a l'echelle microscopique. L'ensemble des resultats obtenus par ces trois techniques illustre ainsi la complementarite des apports d'une approche experimentale combinant sondes structurales locales et methodes donnant acces a des phenomenes de plus longue portee (charge effective dynamique, ondes elastiques).
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Koonrugsa, Nirada. "The role of fission yeast microtubule associated protein, Alp14, in microtubule stabilisation and spindle assembly checkpoint maintenance." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1445635/.
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Accurate and timely chromosome segregation of replicated DNA during cell division is crucial to cell integrity. This process requires mitotic spindles to physically interact with sister kinetochores located at the centromeres. Proteins that function to facilitate this crucial interaction include regulators of microtubule dynamics such as microtubule associated proteins. This thesis primarily describes the study of fission yeast microtubule associated protein, Alp 14 by domain analysis. We report the surprising finding that despite high structural conservation, the two TOG domains in Alp 14 are required for distinct mechanisms. From our consistent data, the first TOG domain (TOG1 - resides at the N-terminus) is shown to be required for the spindle assembly checkpoint. Its deletion results in failure to maintain the spindle checkpoint in spindle damaged conditions, while its overproduction causes hyper-activation of the checkpoint without spindle damage. The second TOG domain (TOG2 - resides near the centre of the proteins), on the other hand, is required for microtubule stabilisation. Further analysis of the role of TOG 1 in the spindle assembly checkpoint suggests that Alp 14 may maintain the checkpoint via the outer kinetochore Nuf2/Ndc80 complex. Alp 14 is found to bind to Nuf2, while deletion of TOG 1 causes Nuf2 and Ndc80 to be delocalised from kinetochore in spindle damaged conditions. In this thesis, we have also studied the interaction of Alp 14 with kinesins Klp5 and Klp6. Our results show that Klp5 and Klp6 are essential for accurate chromosome segregation, promote microtubule depolymerisation and suggest that the kinesins are required for tension-generation at the kinetochore in metaphase. Surprisingly, although the function of Klp5/Klp6 in microtubule regulation is opposed to that of Alpl4/Disl, the proteins collaborate to ensure accurate chromosome segregation.
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Ye, Jianting. "Fabrication analysis and lithium doping in 4 Å carbon nanotubes in the channels of AlPO4̳-5 crystal /." View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202002%20YE.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002.<br>On t.p. "4̳" is subscript. Includes bibliographical references (leaves 84-86). Also available in electronic version. Access restricted to campus users.
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CONANEC, ROLAND. "Synthese et caracterisations physicochimiques de nouveaux metallophosphates azotes catalyseurs basiques alpon, phases cubiques de type na#3alp#3o#9n." Rennes 1, 1994. http://www.theses.fr/1994REN10199.
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Cette etude s'inscrit dans un cadre general de recherches sur de nouveaux phosphates azotes de type nitrure. On a mis en evidence dans cette classe de materiaux deux nouvelles familles de metallophosphates azotes. Les oxynitrures designes par la formule generale alpon constituent la partie essentielle de l'etude. Ces aluminophosphates azotes sont des catalyseurs basiques performants. La deuxieme famille comprend deux series de composes representes par l'oxynitrure na#3alp#3o#9n. Les alpon presentent un domaine de composition dans lequel peuvent varier simultanement le rapport p/al et l'enrichissement en azote. Ils sont prepares par chauffage sous ammoniac de poudres reactives de precurseurs oxydes elaborees par chimie douce. De grandes surfaces specifiques sont conservees apres nitruration. Les poudres de alpon et de leurs precurseurs alpo, amorphes aux rayons x, ont ete caracterisees par analyse bet et microscopie meb. Leur etude par spectroscopies rmn (#2#7al, #3#1p) et drift a permis une premiere approche structurale. La caracterisation de l'acido-basicite de surface des oxynitrures alpon montre que la substitution azote/oxygene cree une forte basicite. L'activite catalytique a ete etudiee dans deux types de reactions: condensations de knoevenagel (catalyseur alpon), synthese de mibk a partir d'acetone (catalyseur ni/alpon). Les oxynitrures cristallises de symetrie cubique dont le representant est na#3alp#3o#9n se repartissent en deux series de composes isostructuraux, de composition generale m#i#3m#i#i#ip#3o#9n et m#i#2m#i#i#2p#3o#9n. La deuxieme serie est representee par l'oxynitrure na#2mg#2p#3o#9n. On a determine la structure cristalline de na#3alp#3o#9n sur monocristal et etendu l'investigation structurale a na#2mg#2p#3o#9n a partir des resultats rmn
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Silva, Arilson Jos? do Nascimento. "Estudo da regenera??o de aditivos para catalisadores de craqueamento aluminofosfatos (ALPO s)e silicoaluminofosfatos (SAPO s)." Universidade Federal do Rio Grande do Norte, 2007. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17595.
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Previous issue date: 2007-11-12<br>Heterogeneous catalysts such as aluminophosphate and silicoaluminophosphate, molecular sieves with AEL of ALPO-11 and SAPO-11, were synthesized by the hydrothermal method with the following molar composition: 2.9 Al +3.2 P + 3.5 DIPA
+32.5 H20 (ALPO-11); 2.9 Al +3.2 P + 0.5 Si + 3.5 DIPA +32.5 H20 (SAPO-11) starting from silica (only in the SAPO-11), pseudoboehmite, orthophosphoric acid (85%) and water, in the presence of a di-isopropylamine organic template. The
crystallization process occurred when the reactive hydrogel was charged into a vessel and autoclaved at 170?C for a period of 48 hours under autogeneous pressure. The
obtained materials were washed, dried and calcined to remove the molecular sieves of DIPA. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), thermo gravimetric differential thermal analysis (TG/DTA) and nitrogen adsorption (BET). The acidic properties were determined using adsorption of n-butylamine followed by programmed thermodessorption. This method revealed that ALPO-11 has weaker acid sites due to
structural defects, while SAPO-11 shows an acidity that ranges from weak to moderate.
However, a small quantity of strong acid sites could be detected there. The deactivation
of the catalysts was conducted by the cracking of the n-hexane in a fixed bed continuous
flow microrreator coupled on line to a gas chromatograph. The main products obtained
were: ethane, propane, isobutene, n-butane, n-pentane and isopentane. The Vyazovkin
(model-free) kinetics method was used to determine the regeneration and removal of the
organic template<br>Foram sintetizados catalisadores heterog?neos do tipo aluminofosfatos e silicoaluminofosfatos pelo m?todo hidrot?rmico a partir de alumina hidratada (pseudobohemita), ?cido fosf?rico 85%, s?lica gel, ?gua e diisopropilamina (DIPA)
usada como direcionador estrutural org?nico. Estes reagentes foram misturados a fim de obter g?is com as seguintes composi??es: 2.9 Al +3.2 P + 3.5 DIPA +32.5 H20; para
ALPO e 2.9 Al +3.2 P + 0.5 Si + 3.5 DIPA +32.5 H20 para SAPO. O processo de cristaliza??o ocorreu ? temperatura de 170 0C durante 48 h, quando foi poss?vel obter as fases puras para ALPO 11 e SAPO 11. Os materiais obtidos foram lavados com ?gua deionizada, secos e calcinados para remover as mol?culas do direcionador. Os materiais foram caracterizados por difra??o de raios-X (DRX), microscopia eletr?nica de varredura (MEV), espectroscopia de absor??o na regi?o do infravermelho (FTIR), an?lise t?rmica via TG/DTG e adsor??o de nitrog?nio (BET). As propriedades ?cidas
foram determinadas usando adsor??o de n-butilamina seguida de termodessor??o programada. Este m?todo revelou que o ALPO 11 possuem s?tios ?cidos fracos devido a defeitos estruturais, j? a amostra SAPO 11 apresenta uma acidez tipicamente fraca a moderada. Entretanto, uma pequena quantidade de s?tios ?cidos fortes foi detectada. A
desativa??o dos catalisadores foi conduzida pela rea??o de craqueamento do n-hexano em um microrreator catal?tico de leito fixo com fluxo cont?nuo acoplado em linha com
um cromat?grafo a g?s. Como principais produtos foram obtidos: etano, propano, isobutano, n-butano,e n-pentano, isopentano. Para determinar a regenera??o e a remo??o
do direcionador org?nico foi aplicado o m?todo cin?tico Vyazovkin (Model Free)
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Boulogne, Bruno. "Etude par microscopie électronique en transmission et spectroscopie infrarouge des défauts de réseau dans la berlinite AlPO." Grenoble 2 : ANRT, 1987. http://catalogue.bnf.fr/ark:/12148/cb37603290f.
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Martin, Céline. "Etude de phases quasi-unidimensionnelles de gaz de van der waals confines dans la zeolithe modele : alpo#4-5." Aix-Marseille 2, 1996. http://www.theses.fr/1996AIX22078.
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Cette these presente l'etude de la physisorption de gaz simples, principalement d'hydrogene, de methane et de neopentane, dans une zeolithe de type afi: alpo#4-5. Alpo#4-5 est un materiau cristallin microporeux qui possede un reseau unidimensionnel de canaux cylindriques ayant un diametre egal a 7,3 angstrom. La surface interne des micropores est constituee d'un seul type de site d'adsorption de geometrie hexagonale. Par consequent, nous avons qualifie cette zeolithe de matrice hote modele pour le confinement de phases quasi-unidimensionnelles ou unidimensionnelles. Apres la caracterisation de divers echantillons d'alpo#4-5, une etude des proprietes thermodynamiques des phases confinees est menee par volumetrie et microcalorimetrie isotherme d'adsorption. Celle des proprietes structurales et dynamiques est respectivement realisee par diffraction et diffusion quasi-elastique incoherente de neutrons. L'influence de la dimension moleculaire du gaz confine est observee au cours de ces experiences. De par leur taille les molecules de neopentane sorbees dans alpo#4-5 representent un bon exemple geometrique de systeme unidimensionnel et par la meme de single-file diffusion (les molecules ne peuvent pas se croiser dans les micropores). Qu'en est-il des proprietes dynamiques d'un tel systeme ? le principal resultat de ce travail est la caracterisation detaillee de la transition observee lors de l'adsorption de methane dans alpo#4-5 (57<t(k)<117). Grace a la complementarite des techniques citees precedemment et au caractere modele du confineur, c'est un nouveau type de changement de phase qui est mis en evidence dans les materiaux microporeux: fluide (quasi-1d) <=> solide (quasi-1d) commensurable i <=> solide (quasi-1d) commensurable ii
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Gomes, Kalyanne Keyly Pereira. "S?ntese e caracteriza??o de aluminofosfato impregnado com molibd?nio/zinco visando a dessulfuriza??o por adsor??o." Universidade Federal do Rio Grande do Norte, 2011. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15910.
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Previous issue date: 2011-10-27<br>Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico<br>Discussions about pollution caused by vehicles emission are old and have been developed
along the years. The search for cleaner technologies and frequent weather alterations have
been inducing industries and government organizations to impose limits much more rigorous
to the contaminant content in fuels, which have an direct impact in atmospheric emissions.
Nowadays, the quality of fuels, in relation to the sulfur content, is carried out through the
process of hydrodesulfurization. Adsorption processes also represent an interesting alternative
route to the removal of sulfur content. Both processes are simpler and operate to atmospheric
temperatures and pressures. This work studies the synthesis and characterization of
aluminophosphate impregnate with zinc, molybdenum or both, and its application in the
sulfur removal from the gasoline through the adsorption process, using a pattern gasoline
containing isooctane and thiophene. The adsorbents were characterized by x-ray diffraction,
differential thermal analysis (DTG), x-ray fluorescence and scanning electron microscopy
(SEM). The specific area, volume and pore diameter were determined by BET (Brunauer-
Emmet-Teller) and the t-plot method. The sulfur was quantified by elementary analysis using
ANTEK 9000 NS. The adsorption process was evaluated as function of the temperature
variation and initial sulfur content through the adsorption isotherm and its thermodynamic
parameters. The parameters of entropy (ΔS), enthalpy variation (ΔH) and free Gibbs energy
(ΔG) were calculated through the graph ln(Kd) versus 1/T. Langmuir, Freundlich and
Langmuir-Freundlich models were adjusted to the experimental data, and the last one had
presented better results. The thermodynamic tests were accomplished in different
temperatures, such as 30, 40 and 50?C, where it was concluded the adsorption process is
spontaneous and exothermic. The kinetic of adsorption was studied by 24 h and it showed that
the capability adsorption to the adsorbents studied respect the following order: MoZnPO >
MoPO > ZnPO > AlPO. The maximum adsorption capacity was 4.91 mg/g for MoZnPO with
an adsorption efficiency of 49%.<br>As discuss?es sobre o problema da polui??o causada por emiss?es veiculares s?o
antigas e v?m evoluindo com o passar do tempo. A procura por tecnologias mais limpas e as
altera??es clim?ticas cada vez mais frequentes induziram as ind?strias e os ?rg?os
governamentais a impor limites cada vez mais rigorosos para os teores de contaminantes nos
combust?veis, os quais impactam diretamente nas emiss?es atmosf?ricas. Atualmente a forma
de melhorar a qualidade dos combust?veis, quanto ao enxofre, ? atrav?s do processo de
hidrodessulfuriza??o e recentemente, os processos de adsor??o tem se mostrado como uma
alternativa bastante interessante ? remo??o de enxofre, pois tais processos s?o mais simples e
operam a temperaturas e press?es atmosf?ricas. O presente trabalho contempla a s?ntese e
caracteriza??o do aluminofosfato impregnado com zinco, molibd?nio ou ambos e sua
aplica??o no estudo da remo??o de enxofre da gasolina atrav?s do processo de adsor??o,
utilizando uma gasolina modelo contendo iso-octano e tiofeno. Os adsorventes foram
caracterizados por difra??o de raios-X, an?lise termogravim?trica (ATG), fluoresc?ncia de
raios-X e microscopia eletr?nica de varredura (MEV). A ?rea espec?fica, volume e di?metro
de poros foram determinados pelo m?todo BET (Brunauer-Emmet-Teller) e m?todo t-plot. O
enxofre foi quantificado por analise elementar atrav?s do ANTEK 9000 NS. O Processo de
adsor??o foi avaliado em fun??o da varia??o da temperatura e da concentra??o inicial de
enxofre atrav?s das isotermas de adsor??o e de seus par?metros termodin?micos. Os
par?metros varia??o de entropia (ΔS), varia??o de entalpia (ΔH) e varia??o da energia livre de
Gibbs (ΔG) foram calculados pelo gr?fico de ln(K) versus 1/T. Os modelos de Langmuir,
Freundlich e Langmuir-Freundlich foram ajustados aos dados experimentais, tendo o ?ltimo
apresentado os melhores resultados. Os testes termodin?micos foram realizados nas
temperaturas de 30, 40, 50 ?C e constatou-se que o processo de adsor??o ? espont?neo e
exot?rmico. A cin?tica da adsor??o foi estudada por 24 horas e mostrou que a capacidade de
adsor??o para os adsorventes estudados segue a seguinte ordem: MoZnPO > MoPO > ZnPO >
AlPO. A capacidade m?xima de adsor??o foi 4,91 mg/g para o MoZnPO com uma efici?ncia
de adsor??o de 49%.
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Sneddon, Scott. "Characterisation of inorganic materials using solid-state NMR spectroscopy." Thesis, University of St Andrews, 2016. http://hdl.handle.net/10023/8239.
Full textAbstract:
This thesis uses solid-state nuclear magnetic resonance (NMR) spectroscopy and density functional theory (DFT) calculations to study local structure and disorder in inorganic materials. Initial work concerns microporous aluminophosphate frameworks, where the importance of semi-empirical dispersion correction (SEDC) schemes in structural optimisation using DFT is evaluated. These schemes provide structures in better agreement with experimental diffraction measurements, but very similar NMR parameters are obtained for any structures where the atomic coordinates are optimised, owing to the similarity of the local geometry. The ³¹P anisotropic shielding parameters (Ω and κ) are then measured using amplified PASS experiments, but there appears to be no strong correlation of these with any single geometrical parameter. In subsequent work, a range of zeolitic imidazolate frameworks (ZIFs) are investigated. Assignment of ¹³C and ¹⁵N NMR spectra, and measurement of the anisotropic NMR parameters, enabled the number and type of linkers present to be determined. For ¹⁵N, differences in Ω may provide information on the framework topology. While ⁶⁷Zn measurements are experimentally challenging and periodic DFT calculations are currently unreliable, calculations on small model clusters provide good agreement with experiment and indicate that ⁶⁷Zn NMR spectra are sensitive to the local structure. Finally, a series of pyrochlore-based ceramics (Y₂Hf₂₋ₓSnₓO₇) is investigated. A phase transformation from pyrochlore to a disordered defect fluorite phase is predicted, but ⁸⁹Y and ¹¹⁹Sn NMR reveal that rather than a solid solution, a significant two-phase region is present, with a maximum of ~12% Hf incorporated into the pyrochlore phase. The use of ¹⁷O NMR to provide insight into the local structure and disorder in these materials is also investigated. Once the different T₁ relaxation and nutation behaviour is considered it is shown that quantitative ¹⁷O enrichment of Y₂Sn₂O₇ is possible, and that ¹⁷O does offer a promising future tool for study.
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Wu, Yi-hsun, and 吳毅洵. "Phenol synthesis using mesoporous Cu/AlPO4 catalysts." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/00859397676392742455.
Full textAbstract:
碩士<br>國立臺灣科技大學<br>化學工程系<br>98<br>The catalytic performances of various copper (Cu) supported on modified aluminophosphate (AlPO4) substrates during hydroxylation of benzene to phenol have been investigated. Modified catalyst supports prepared by different methods, namely by coating AlPO4 onto the surfaces of the mesoporous SBA-15 molecular sieve (denoted as Cx-AlPO4/SBA), by incorporating AlPO4 in the pore channels of SBA-15 (denoted as Sx-AlPO4/SBA), or by direct synthesis of mesoporous AlPO4 (denoted as mesoAlPO4) have been examined together with bare SBA-15 and traditional microporous AlPO4 (microAlPO4). Subsequently, ca. 1 wt% of Cu was loaded onto the respective supports by the impregnation method.
The physicochemical properties of various supported catalysts were characterized by a variety of analytical and spectroscopic techniques, viz. XRD, BET, TEM, NH3-TPD, and 27Al and 31P MAS NMR. The structures of AlPO4 as well as the SBA-15 were found to remain intact in the modified catalysts regardless of the methods invoked for the preparation of various catalyst supports. In terms of acid concentrations, the following trend was observed: Sx-Cu/AlPO4/SBA >> Cx-Cu/AlPO4/SBA ?l Cu/mesoAlPO4.
The catalytic activities of various catalysts for the production of phenol were tested under liquid phase using benzene and hydrogen peroxide as the reactants and acetonitrile as the solvent. The latter was introduced to warrant a homogeneous mixture of the reactants. Typically, the reaction was conducted at 60℃ under ambient pressure, and the products were analyzed by a gas chromatography equipped with a flame ionization detector (GC-FID). It was found that the catalyst prepared by duplicated AlPO4 coating (C2-Cu/AlPO4/SBA) exhibited a better activity than the catalyst support coated only once (C1-Cu/AlPO4/SBA). Moreover, the catalytic activities of various supported catalysts follow the following trend: C2-Cu/AlPO4/SBA > Cu/mesoAlPO4 > C1-Cu/AlPO4/SBA >> Cu/AlPO4 ?d Sx-Cu/AlPO4/SBA >> Cu/SBA-15. Additional life tests revealed that the durability/stability of the modified catalysts followed the trend: Cu/mesoAlPO4 > Cx-Cu/AlPO4/SBA > Sx-Cu/AlPO4/SBA, which is in agreement with the observed trend in their respective deactivation constants. Thus, it is indicative that the activity of the supported Cu catalysts should be associated with the structures of the AlPO4-modified substrates rather than their acid concentrations.
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Chen, Chih-Chang, and 陳峙彰. "The Synthesis and Characterization of AlPO4-5 Zeolite Membrane." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/16183505927038621785.
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Wang, G. T., and 王國鎮. "Synthesis of AlPO4-5 and the elimination of alcohol from acetaldehydedimethyl acetal." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/27302088186728219769.
Full textAbstract:
碩士<br>國立中央大學<br>化學工程研究所<br>82<br>This study includes two parts. In the first part, We try to
synthesis uniform large crystal of AlPO4-5 for materials
application, and study each parameter on the influence of
growing To obtain large and uniform AlPO4-5 by hydrothermal
treatment, when gel comopsition:(C2H5)N:Al2O3:P2O5:
H2)=1.55:1:1:600, aluminua source obtained from hydrosis of
pseudo boehmite is better than In the elimination alcohol of
acetaldehydedimethyl acetal (DMA),the results reveal that,
selectivity over each zeolite catalysts is very high (near
100%),but the aluminaphosplate Under 1 atm , WHSV=27hr-1,With
increasing tempature to 250℃,the conversion of AlPO4-5,SAPO-5
is 100%.Strong acid active site helps the double bond products
MVE polymerization in large
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You-ZenChen and 陳囿任. "Preparation of AlPO4-5 type zeolitic materials from aluminum dross via hydrothermal reaction." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/29405868233674125770.
Full textAbstract:
碩士<br>國立成功大學<br>資源工程學系<br>103<br>The problem of pollution arise along with the rapid development of scientific and technological advances. In order to reduce the harm for human pay more attention to industrial waste treatment. Aluminum is one of the main components of natural rock and soil. After recovering scrap aluminum often recycled, but the process will be along with a large amount of aluminum nitride which in contact with water will form ammonia and heavy metals, leading to environmental pollution caused public controversy. Zeolite minerals with adsorption and ion exchange properties, are considered one of the best purification materials.
Organic template is used as trimethylamine(TEA) in this experiment, we used template ratio(TEA/Al2O3=0.5~1.5)、water ratio(H2O/Al2O3=20、40、60)、reaction temperature(150 oC、180 oC、210 oC)、calcination temperature(450 oC、550 oC、650 oC) and hydrothermal time 10hr were discussed on the effect of zeolite synthesis experiment. The results showed that all the numerical values of BET are bigger than references and also NH4+ ion absorption capacity of the three samples are all better than nature zeolite minerals.
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Lin, L. J., та 林稜偕. "Micrpwave synthesis SAPO-11, AlPO4-5, MCM-41 and analysize NiO/ γ-Al2O3 environment by EAXFS". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/17766292607877003642.
Full textAbstract:
碩士<br>國立中央大學<br>化學工程學系<br>86<br>AbstractThere are two parts in his thesis. The first part is the
microwave syntheses of SAPO-11, AlPO4-5, SAPO-34 and MCM-41. The
second part is to study the environment of Ni in NiO/γ-Al2O3 by
EXAFS.In the first part, microwave heating is applied to the
syntheses of AlPO4-5, SAPO-11, SAPO-34 and MCM-41. The products
are characterized by XRD, SEM, MAS-NMR, and ICP-AES. The effects
of water content, template, aluminum source, heating time,
preheating time and secondary synthesis are investigated.
Microwave heating provides a convenient way to synthesize
zeolites in a short time. AlPO4-5 crystals can be obtained after
5 min heating. SAPO-11 crystals appear at 170℃ after 4 hr
heating when aluminum triisopIn the second part, EXAFS is used
to study the environments of Ni in NiO/γ-Al2O3 with different
amounts of NiO loading below the monolayer dispersion capacity.
The coordination number of Ni in the low NiO loading sample is
four. The coordination number of Ni increases with increasing
NiO loading and approaches six with NiO loading of monolayer
capacity.
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Jiang, Ji Fen, та 蔣計芬. "在ALPO4-5,SSZ_24沸石中大小不同之有機分子之吸附行為模擬". Thesis, 1995. http://ndltd.ncl.edu.tw/handle/48084069113003965915.
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Deroche, Christiane [Verfasser]. "Experimentelle und rechnerische Analyse des Einbaus von Sorbatmolekülen in die Wirtsstrukturen der 12-Ring-Kanalsysteme ZSM-12 (MTW) und AlPO4-5 (AFI) / vorgelegt von Christiane Deroche." 1999. http://d-nb.info/966143795/34.
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王四慶. "Loading and catalytic properties of MoO �邕n AlPO ��-5 support". Thesis, 1988. http://ndltd.ncl.edu.tw/handle/31012768596196586794.
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DAI, GIN-YAO, та 戴欽堯. "Silicalite 及ALPO-5上乙烷的氧化脫氫". Thesis, 1988. http://ndltd.ncl.edu.tw/handle/33793342986369891647.
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"Theoretical study on the 4Å carbon nanotube growth mechanisms inside microporous AlPO₄-5." Thesis, 2009. http://library.cuhk.edu.hk/record=b6074778.
Full textAbstract:
In the first part, the mechanisms for the dissociation of TPA are studied under three types of conditions. The unimolecular dissociation is initiated by the breaking of either the N-Calpha and Calpha -Cbeta bonds and leads to many complicated processes. Within the confined space inside neutral zeolite channels, the diffusion of H radicals enhances a cycle of reactions, which accounts for the experimental observation of dipropylamine and monopropylamine. In the presence of an acidic site, the dissociation of TPA goes through catalyzed successive steps to produce ammonia and propylene molecules.<br>In the last part, two distinct paths are proposed to investigate the carbon nanotube growth mechanism using benzene as the growth seed and propylene as carbon resource. There is an incremental aromatization process, involving both alkylation and dehydrogenation, that leads to linked aromatic rings to form either (3,3) tube or (4,2) tube. Two paths are identified, one via toluene and the other via cumene. The cumene path is more favorable as the barrier is significant lower.<br>In the second part, A T5 cluster model is used to investigate mechanisms of propylene aromatization to benzene, which involves chemisorption, dimerization, cyclization and dehydrogenation. Propylene can be chemisorbed to form two distinct products, n-propoxide and i-propoxide, which can further be dimerizated to form longer chain olefins 1-hexene and 2-hexene (from n-propoxide), and 4-methyl-1-pentene and 4-methyl-2-penetene (from i-propoxide). Initiated by H2 elimination, these dimerization products can further go through cyclization process to generated either 6-member ring cyclohexene or 5-member ring methyl-cyclopentene. Catalyzed by zeolite, cyclohexene can directly dehydrogenate to form benzene whereas methyl-cyclopentene can dehydrogenate to form fulven, an isomer to benzene. Under acidic zeolite environment, a fulvene can readily be transformed to the thermodynamically more stable benzene.<br>The growth mechanisms of mono-sized and parallel-aligned single wall carbon nanotube (CNT) in the microporous channels of AlPO4-5 are investigated by density functional theory calculations. Detailed mechanisms are proposed for the decomposition of TPA, the formation of aromatic ring, and the growth of carbon nanotubes.<br>Liu, Jianwen.<br>Adviser: Zhifeng Liu.<br>Source: Dissertation Abstracts International, Volume: 70-09, Section: B, page: .<br>Thesis submitted in: December 2008.<br>Thesis (Ph.D.)--Chinese University of Hong Kong, 2009.<br>Includes bibliographical references (leaves 98-99).<br>Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.<br>Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.<br>Abstracts in English and Chinese.<br>School code: 1307.
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Cirota, Mervyn. "Towards an understanding of the limitations of the Alexandra renewal project: The ALPOA court interdict and its impact." Thesis, 2017. https://hdl.handle.net/10539/24611.
Full textAbstract:
A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in partial fulfillment of the requirements for the degree of Master of the Built Environment<br>Alexandra Township located north of Johannesburg was established in 1912. It has an infrastructural capacity of 70 000 people and is now populated by an estimated 400 000 residents. It covers 800 hectares including Alexandra Proper (Old Alexandra) and the East Bank. The Alexandra Renewal Project (ARP) was initiated in 2001 with an initial budget of R1.3 billion to be used over 7 years in furtherance of a programme that would improve infrastructural shortcomings in housing, roads, water supply and sanitation. It would also facilitate the upgrade of housing and create new housing opportunities.
Arising from discussions held between the City and two organizations representing the residents, Alexandra Land and Property Owners’ Association (ALPOA) and the Alexandra Property Owners’ Rights Organization (APOR), an amount of R50 000 was paid to some of the residents. A dispute then arose and ALPOA and APOR obtained an interdict against the City of Johannesburg to prevent the expropriation of their land without appropriate compensation. This court order has had the effect of restricting redevelopment in Old Alexandra thus preventing high density and mixeduse development, in situ upgrading and the roll out of rental stock. Despite an arbitration forum being set up and various proposals being considered by both sides, no solution has yet been reached.
The purpose of the study is to examine through a qualitative approach, the underlying causes leading to the dispute between the city and the residents, the basis for the granting of the court order, the impact this court order has had on the property owners, and the underlying reasons as to why the dispute has not been resolved. This study also seeks possible solutions to the dispute and makes certain recommendations in this regard.
The main research question will be ‘What underlying factors created the environment that compelled ALPOA and others to seek a court interdict?’ The research method will involve interviews with several stakeholders including City and Provincial officials, ALPOA and APOR executives as well as property owners and residents affected by the court interdict. The expected finding will be that government has failed to deal with the problem, has failed to effectively bring the private sector on
board, has systemic governmental problems and is beset with incompetence and corruption.
The research is underpinned by the inhumane and unacceptable living conditions in Alexandra and the motivation for the ARP project and its challenges. Key concepts of the research will be to pose the main research questions, to identify the problem and examine its underlying causes, to follow a systematic and organized procedure in collecting information, to analyze the information gathered and to determine whether the findings tie in with the hypothesis set out above<br>GR2018
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Tai, Chen-Yi, and 戴禎儀. "Low-Loss Microwave Dielectrics in the Spinel-structured (Mg1-xM2+x)Al2O4 (M2+ = Zn and Ni) Solid solutions." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/27730138195398650458.
Full textAbstract:
碩士<br>國立成功大學<br>資源工程學系碩博士班<br>97<br>MgAl2O4 -based microwave dielectric ceramics substiute Mg by Zn and Ni were synthesized using the solid state reaction forming spinel solid solution of
(Mg1-xMx')Al2O4，M' = Zn and Ni.
Dense ceramics were obtained by sintering at 1480℃ to 1600℃, in air for 3 h.
It can be observed from X-ray diffraction result that the single phase solid solutions.
The microwave dielectric properties of MgAl2O4,
the dielectric constant 7.67-7.99, Q×f ~ 86,000 and τf -65 ~ -68 ppm/℃.
With small amount Zn ion substitution for Mg^(2+)at x = 0.05, The dielectric constant of (Mg0.95Zn0.05)Al2O4 from 7.93 to 8.11, compare with MgAl2O4 ,
ceramics while the Q×f value had significantly improved up to maxmal value of 156,000 GHz (15.6 GHz) and τ_f values from –55 to –70 ppm/℃.
Moreover,MgAl2O4 microwave dielectric ceramics were modified by Ni ion substitution for Mg forming (Mg1-xNix)Al2O4 at x = 0-1.
The compounds NiAl2O4 , dielectric constant ~ 7.78–8.04, Q×f ~ 62,000 GHz and τf ~ –48~ –50 ppm/℃. With Ni ion substitution for Mg ion at x = 0.25, the Q×f
increase to 130,000 GHz (15.4 GHz), εr ~ 8.18–8.21 and τ_f from –51 to –65 ppm/℃.
Relying on the result, it could be discussed the relationship of spinel solid solution structure and
microwave dielectric properties, including grain size, density and ionic polarizability in the (Mg1-xMx')Al2O4，M' = Zn and Ni system.
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Chuang, Chen-Yao, and 莊振堯. "Effect of glass composition (Mg0.5Zn0.5)Al2O4/ SiO2 ratio on the crystallization and properties of MgO-ZnO-Al2O3-SiO2 glass-ceramics." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/35926661422045100533.
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