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1
Baradie, Bilal. "Membranes ionomères composites pour piles à combustibles H2/O2 : élaboration et caractérisation." Grenoble INPG, 1997. http://www.theses.fr/1997INPG0002.
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Dans le but de fournir une alternative aux membranes perfluorees pour piles a combustible a electrolyte polymere, plusieurs membranes polymeres a conduction protonique ont ete elaborees et caracterisees leurs proprietes electrochimiques et physiques, notamment leur stabilite mecanique et thermique, ont ete etudiees. La premiere famille de membranes est obtenue, par dispersion d'une poudre inorganique superconductrice protonique (h#3sb#3p#2o#1#4,xh#2o, = 10#-#2s. Cm#-#1) dans une matrice polymere commerciale epdm. Malgre leurs conductivites assez elevees, ces membranes composites ne repondent pas aux exigences requises, en raison de la chute ohmique qu'elles occasionnent et de leur permeabilite aux gaz. Dans la deuxieme approche, nous avons selectionne, comme matrice polymere, un ionomere thermoplastique, pss, ce dernier etant prepare par sulfonation du poly (arylene ether sulfone). Ces membranes composites repondent au cahier des charges des piles a combustible a membrane echangeuse de proton, notamment en matiere de stabilite thermique, mecanique et electrochimique ; leur conductivite protonique etant voisine de celle de nafion# 117. De plus, elles presentent une permeabilite aux gaz bien inferieure a celle du nafion# 117 et ont ete evaluees avec succes sur un banc de test pendant 500 heures. Enfin, leur prix assez faible permettrait d'envisager une industrialisation dans un proche avenir.
2
Nieboer, Jared, and University of Lethbridge Faculty of Arts and Science. "The preparation and characterization of tungsten and molybdenum sulfide fluorides." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2007, 2007. http://hdl.handle.net/10133/668.
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Silanethiolate salts of K(18-crown-6)+, N(CH3)4
+, Cs+, K+ were synthesized and
characterized by vibrational and NMR spectroscopy. The [N(CH3)4][SSi(CH3)3] salt was
used to prepare the new [N(CH3)4][WSF5] salt directly from WF6. Alternatively,
[N(CH3)4][WSF5] was prepared by the reaction of WSF4 with [N(CH3)4][F].
Pure WSF4 was prepared via a facile new route and was fully characterized by
Raman, infrared, and 19F NMR spectroscopy, and an improved crystal structure. The
Lewis-acid properties of WSF4 were studied in reactions with pyridine, yielding the new
WSF4·C5H5N adduct, which was studied by Raman and 19F NMR spectroscopy. A 2:1
stoichiometry of WSF4 and [N(CH3)4][F] yielded W2S2F9
- in solution. The novel
W2SOF9
- anion was characterized in solution by 19F NMR spectroscopy.
Molybdenum sulfide tetrafluoride was synthesized and unambiguously
characterized by Raman, infrared, and 19F NMR spectroscopy and single-crystal X-ray
diffraction.
The experimental characterization of WSF4, MoSF4, WSF5
-, and SSi(CH3)3
- was
supplemented by density functional theory calculations.<br>xv, 131 leaves : ill. ; 29 cm.
3
Ling, Yuanbing 1970. "Direct preparation of alpha-calcium sulfate hemihydrate from sulfuric acid." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84283.
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In this work, the crystallization of alpha-calcium sulfate hemihydrate in sulfuric acid solution and the correlation between its properties and preparation conditions by reaction of sulfuric acid with lime (CaO) have been thoroughly investigated. The research involved the study of conversion-dissolution of calcium sulfate dihydrate in H2SO4 solution, the measurement of solubilities, thermo-dynamic calculations and the preparation of alpha-CaSO4 ·0.5 H2O via different methods of reactive mixing of H2SO4 and CaO. It was found that the calcium sulfate solids can saturate the sulfuric acid solutions in only 5 minutes. The solubility of calcium sulfate hemihydrate in 0--3.0M H 2SO4 solution at 100°C was experimentally determined and thermodynamic calculations with the aid of FactSage and OLI have led to establishment of the phase diagram for the CaSO4-H2SO 4-H2O system. An operating window has been determined in terms of H2SO4 concentration, temperature and time within which alpha-hemihydrate can be produced by reaction of lime with H 2SO4. This window is defined as 0.6--1.1M H2SO 4 (steady-state concentrations), 98--105°C and 1 hour retention time. Dihydrate was found to form as intermediate phase quickly converting to hemihydrate. The kinetics of conversion depends on the acidity level.<br>For the standard preparation procedure of adding lime into hot sulfuric acid, alpha-hemihydrate grows in the c-axis direction much more rapidly than in other directions ending in the form of fine needle crystals. Also, independent of the shape of the seed particles, the resultant crystals of hemihydrate are needle-shaped, which suggests a "dissolution-recrystallization" mechanism. Upon prolonged equilibration in their acid-preparation solution hemihydrate needle-shape crystals become fibrous and eventually convert to anhydrite. It is believed that uptake of SO42- instead of Ca2+ is the rate-determining step in the hemihydrate crystallization process. The hot SO42--rich environment rendered most of the additives (particularly organic) tried ineffective. Trivalent cations such as Fe3+ and Al3+, are the only ones found to modify the crystal morphology from needle-shape to small "grain" type morphology.<br>Slow addition of H2SO4 solution to slaked lime - reverse procedure was found to favor the production of alpha-hemihydrate with column-shaped as opposed to needle-shaped crystal morphology within otherwise the same operating window, 0.6--1.1M H2SO4. Preliminary assessment of the properties of the alpha-hemihydrate materials synthesized in this work showed them to compare satisfactorily with other materials produced by conversion of dihydrate to hemihydrate.
4
ZHANG, DA. "Preparation des 1-t-butoxyalkyl phenyl sulfones et leur utilisation en synthese organique." Paris 6, 1991. http://www.theses.fr/1991PA066661.
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La t-butoxymethyl phenyl sulfone peut etre facilement preparee, metallee et condensee avec des halogenures ou des composes carbonyles. Les 1-t-butoxyalkyl phenyl sulfones obtenues peuvent etre hydrolysees dans des conditions douces pour donner les aldehydes correspondants et methanolysees pour donner des dimethyl acetals. La t-butoxymethyl phenyl sulfone peut donc agir comme un equivalent d'anion formyle ou d'anion dimethoxymethyle. Les 1-t-butoxyalkyl phenyl sulfones peuvent etre alcoolysees pour donner des acetals mixtes. Les alcools peuvent etre proteges sous formes d'ethers t-butoxymethyles qui sont facilement hydrolyses en alcools correspondants. Les 1-t-butoxyalkyl phenyl sulfones conduisent aux ethers t-butyles par hydrogenolyse en presence d'hydrures, ou aux 1,2-diols proteges sous forme d'ethers t-butyles par dimerisation reductrice. Les ethers d'enol t-butyles peuvent etre prepares soit par elimination des 1-t-butoxyalkyl phenyl sulfones en milieu basique; soit par un couplage entre l'anion de la t-butoxymethyl phenyl sulfone et l'anion d'une alkyl phenyl sulfone
5
Aytar, Burcu Selin. "Preparation Of Cross-linked Tyrosinase Aggregates." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607318/index.pdf.
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ABSTRACT
PREPARATION OF CROSS-LINKED TYROSINASE AGGREGATES
Aytar, Burcu Selin
M.S., Department of Chemical Engineering
Supervisor: Prof. Dr. Ufuk Bakir
June 2006, 82 pages
The aim of this study was to prepare cross-linked enzyme aggregate (CLEA) from crude mushroom (Agaricus bisporus) extract. However, the optimization of CLEA production was performed by using pure tyrosinase. Important parameters were determined as protein, ammonium sulfate and glutaraldehyde concentrations, CLEA particle size, and cross-linking temperature and period. On the other hand, the order of ammonium sulfate and glutaraldehyde addition did not affect the yield of CLEA. Optimum CLEA preparation conditions were 60 % ammonium sulfate saturation, 2 % (v/v) glutaraldehyde, and 3 hour cross-linking reaction at room temperature. Particle size of the CLEAs should be reduced by mechanical stirring to eliminate mass transfer limitations. Under these circumstances, 100 % recovery was obtained from both pure and crude tyrosinases. Optimum temperature and the activation energy for catechol oxidation were determined as 34 oC and 16.9 kcal/mol for CLEAs, whereas, 32 oC and 12.5 kcal/mol for the free enzyme. Furthermore, the thermostability of CLEAs was significantly higher than the free enzyme. CLEAs, prepared from crude mushroom extract, retained 72 % of its maximum activity in eight months storage at 4 oC. Moreover, changing the storage temperature from 4 oC to room temperature did not decrease CLEAs stabilities.
6
Wimmer, Alexander [Verfasser], and Burkhard [Akademischer Betreuer] König. "Preparation of Sulfoximines, Sulfoximidoyl Derivatives and Sulfones via Visible-Light Photocatalysis / Alexander Wimmer ; Betreuer: Burkhard König." Regensburg : Universitätsbibliothek Regensburg, 2020. http://d-nb.info/1223197956/34.
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Birbas, Daniella. "Preparation of Activated Carbon: Forest residues activated with Phosphoric Acid and Zinc Sulfate." Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-33274.
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Activated carbon is a highly adsorbing material and has various scopes of uses depending on needs. It is used in many industries and applications e.g. to clean industrial wastewater, in medicine, discolor sugar and so on. What makes AC such a good adsorbent is its porous structure which gives it a high surface area. This report consists of three parts; general information about Activated Carbon (AC) and its characteristics, to give the reader a sufficient background about AC for continuous understanding throughout the report, an experimental investigation in chemical activation of carbon with phosphoric acid as the chemical reagent and sawdust from both Cuban and Swedish Pine tree as precursors, and a second experimental investigation in chemical activation of carbon with Zinc Sulfate as the chemical reagent and sawdust from Cuban Pine tree as the precursor. For the first experimental part as well as for the second the objective is how to best combine the three parameters; acid concentration, impregnation ratio and activation temperature in order to get the best adsorption performance when preparing activated carbon with different precursor specimens and chemical reagents. The experiments with phosphoric acid activation show that treatment with 40% acid concentration at 400 °C produce an activated carbon with good properties for ammonia adsorption and good iodine number. If a 30% phosphoric acid is used for activation, an activation temperature of 500 °C is recommended. With an impregnation ratio of 1, good adsorption was obtained in the activated carbon produced from Swedish pine while using Cuban pine a higher adsorption was obtained with an impregnation ratio of 2. The experiments with Zinc Sulfate activation show that influence of the sulfate concentration (between 10 % and 40 %) and temperature (between 400 °C and 500°C) on the properties for ammonia adsorption in the produced activated carbon was considerable for low impregnation ratio (0.5 and 1). In general, activation conditions of 20% zinc sulfate concentration, 400 °C and impregnation ratio: 1 are enough to produce an activated carbon with good properties for ammonia adsorption. The adsorption of carbon tetrachloride was lower. Activated carbons produced with 10 % zinc sulfate concentration, 0.5 impregnation ratio and 400 °C activation temperature (the mildest studied conditions) show already good iodine number and BET surface area. The main conclusion from the thesis work is that the optimal conditions vary widely with wanted results. Therefore a suggestion for future work is to narrow the research to fewer variables and more repetition of the samples.
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BOUCHENAKI, CHOUKRI. "Preparation, caracterisation et proprietes photothermiques bistables de couches minces de sulfure de cadmium." Université Louis Pasteur (Strasbourg) (1971-2008), 1991. http://www.theses.fr/1991STR13105.
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L'objectif de la these etait d'etudier la possibilite de realiser un dispositif seed (self-electrooptic effect device) a partir d'une couche mince de cds deposee sur un substrat transparent. Trois types de preparation ont ete etudies: evaporation sous vide, croissance epitaxiale sur caf2 par transport en phase vapeur a courte distance et pulverisation reactive. Les performances sont tres inferieures a celles attendues a partir du modele theorique existant bien que les couches sur caf2 et spray presentent les qualites optique et photoelectrique admises dans la theorie. L'investigation simultanee des proprietes physiques des couches (diffraction des rayons x, bord d'absorption d'urbach, photoconductivite, photoluminescence, etc. . . ) et de leurs caracteristiques bistables a permis de mettre en evidence les parametres du materiau intervenant dans le fonctionnement du seed. Le modele theorique a ete revu pour tenir compte de tous ces facteurs. Il a ete possible ainsi de comprendre l'origine des performances bistables modestes et de mettre en evidence les directives pour les ameliorer. Un seed presentant des caracteristiques quasi-optimales a 210 k a pu etre realise
9
Yang, Zhiqiang. "Preparation of palladium, palladium sulfide, cadmium selenide nanoparticles and magnesium oxychloride, magnesium hydroxide nanorods." Diss., Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/891.
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Zhang, Heng [Verfasser]. "Wedge-shaped amphiphilic sulfonate molecules : phase behavior, ion conductivity and membrane preparation / Heng Zhang." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2013. http://d-nb.info/1047231921/34.
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Yan, Luke, Rongrong Huang, Jian Xiao, Huiyun Xia, Min Chao, and Sven Wieβner. "Preparation and properties of a composite made by barium sulfate-containing polytetrafluoroethylene granular powder." Sage, 2016. https://tud.qucosa.de/id/qucosa%3A35550.
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Barium sulfate (BaSO₄)-containing polytetrafluoroethylene (PTFE) granular powder was prepared through a two-phase emulsion dispersion granulation method. Because of its large bulk density, small average particle size, narrow particle size distribution, and superior powder flowability, the granular powder is suitable for use in automatic molding machines. The effects of granulation on the tensile strength of the BaSO₄/PTFE composite were investigated, and the composite’s microstructures were characterized and analyzed using scanning electron microscopy. All these indicated that the granulation could make BaSO₄ disperse more homogeneously in PTFE and reduce many defects in molded articles. So the properties of the BaSO4/PTFE composites made by the granular powder were superior to the composite obtained from the nongranular powder. The tensile strength and elongation of the composite obtained from the granular powder could be achieved to a level of 19.4 MPa and 420%, respectively.
12
DE, LIMA CARMEN. "Etude de la condensation de sulfones lithiees avec divers carbenoides mono ou dihalogenes. Application a la preparation d'olefines." Paris 6, 1993. http://www.theses.fr/1993PA066411.
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Ce travail porte essentiellement sur l'etude de la condensation d'anions sulfonyles avec divers carbenoides halogenes. Ces derniers ont des proprietes electrophiles, et leur reaction avec des sulfones lithiees conduit a des olefines halogenees ou non. Les resultats obtenus sont presentes dans trois chapitres. Le chapitre 1 est consacre aux carbenoides dichlores qui, par condensation avec les carbanions alpha-sulfonyles conduisent aux 1-haloalcenes attendus avec de bons rendements. Dans le chapitre 2 la reaction de condensation d'electrophiles plus classiques sur la 2-methylcyclopentyl phenyl sulfone est decrite. Dans le chapitre 3 la preparation des carbenoides monohalogenes magnesies est decrite. Leur condensation sur divers carbanions alpha-sulfonyles conduit, par methylenation et alkylidenation, aux olefines non fonctionnalisees attendues avec de bons rendements
13
DADKHAH, MEHRAN. "Preparation and characterization of a Novel mesoporous bioactive glass/calcium sulfate cement for vertebroplasty application." Doctoral thesis, Politecnico di Torino, 2017. http://hdl.handle.net/11583/2678646.
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Vertebral compression fractures (VCFs) are deformities of the vertebral body that usually do not require an open surgical approach and are often due to osteoporosis or low energy trauma. They may be healed by themselves with a conservative management: brace support and bed rest, combined with the administration of analgesics and bisphosphonates. When the non-surgical approach is not effective, VCFs usually lead to untreatable pain, spine deformity and disability with a proven increase of mortality, especially in patients with poor conditions. Vertebroplasty and kyphoplasty are known as alternative minimal invasive approaches to VCFs. They are two percutaneous spine interventions which are performed with the goal of back pain relief and, when possible, restoring of the vertebral height. Vertebroplasty involves the injection of a bone cement through the trabeculae of the fractured vertebral body. In this procedure, cement injection is performed under continuous radiological control through a needle inserted in the vertebra by a transpedicular percutaneous approach. In kyphoplasty, a balloon tamp is inserted through a vertebroplasty needle in the fractured vertebral body and then is inflated/deflated and the created cavity is filled with the bone cement injected through a needle. In randomized trials it was found that VP and KP are equally safe and significantly superior to conservative treatment.
Injectable bone cements play a critical role in the effectiveness of vertebroplasty and kyphoplasty. Regarding the bone replacement, several investigations have been focused on the materials exhibiting good bioactivity, biodegradability and biocompatibility. Injectable bone cements can be divided into various categories. The first group is polymer based cements which show unique properties due to their flexibility of composition. However, their poor mechanical strength limits their applications. Metals are considered as the second group that has high wear resistance, strength and ductility. However, their high rate of corrosion and low biocompatibility make them undesirable for living tissue. In addition, allergic reactions can occur due to the high diffusion of metal ions. Another group of materials are ceramics which possess generally good biocompatibility. Although these materials have resistance to corrosion and compression, they are brittle with low fracture strength. Calcium phosphate and calcium sulphate cements could be applicable as biomaterials for vertebral
stabilization and augmentation. Nevertheless, their clinical applications have been limited due to some shortcomings. Currently, the number of commercial calcium sulphate-based cements is limited. Therefore, in recent years, several approaches have been proposed to develop the synthetic calcium-based bone cements.
The aim of the present research was the synthesis of a mesoporous bioactive glass (MBG) by spray-drying a mild acidic aqueous synthesis solution. These particles are able to chemically bond to the bone and can be also utilized for targeted drug delivery. In order to synthesis the MBG particles, the classical methods are time-consuming due to the additional steps to obtain the final powders. Moreover, these methods are usually performed with ethanol-based solution which is flammable and expensive. Spray-drying can be considered as a single step production technique to transform a fluid feed to a dried solid powder. In fact, the spray-drying approach can be used as an effective alternative to the standard routes with faster kinetics which allows to produce the particles with controlled size and morphology. It is reported that the spray-dried mesoporous bioactive glasses or functionalized silica have been already produced by spraying synthesis solutions based on flammable solvents (mostly ethanol) under an inert atmosphere.
In general, the effective procedures involve both safety and economic constraints for a future manufacturing scale-up. In this study, MBG particles were produced by the combination of sol-gel synthesis in an aqueous medium and spray-drying technique, which can be a further improvement in terms of safety, cost and environment.
The second aim of this study was to develop an innovative injectable and bioresorbable composite cements based on alpha calcium sulphate hemihydrate as a resorbable matrix, enriched with mesoporous glass particles (to impart bioactivity) and a glass-ceramic radiopaque phase. The present work was in the frame of the European Union Seventh Framework Program (FP7/2007- 2013) under grant agreement no. [280575]-Restoration. During this study, the developed injectable cements were characterized in terms of physical and mechanical properties such as setting time, injectability and compressive strength. Moreover, in vitro bioactivity and degradability of prepared composite cements were assessed in simulated body fluid (SBF). Biological tests using rat bone marrow stromal cells were also carried out in vitro. In addition, further investigations were carried out in vivo by using large animal model (sheep).
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Watanabe, Joy Kimi. "Silicon preparation techniques for nucleation and growth studies of zinc sulfide deposited by atomic layer epitaxy." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185938.
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Zinc sulfide with a direct bandgap of 3.6 eV is a potential candidate as blue-light emitting diodes and lasers. Initial growth of ZnS on Si(100) substrates by atomic layer epitaxy (ALE), a deposition technique in which film growth ideally proceeds in a 2-dimensional, layer-by-layer manner, has been investigated. The interaction between the first layer of atoms of the film and the substrate surface initiates film growth and affects the resulting structure. Work has focused on the effects of surface composition, (particularly on the role of sulfur) on the initial growth of ZnS on Si(100), and thus the chemical composition must be well controlled and characterized. Three methods have been used to process Si(100) substrates. The first was a wet chemical clean with either HF or H₂O passivation followed by a low temperature (700-800°C) anneal in UHV. The second processing method was ion sputter cleaning with a post-sputter anneal at 800-900°C. The third technique irradiated substrates held in UHV with a beam from a KrF excimer laser. Initial layers of ZnS (from Zn and H₂S) were then deposited onto processed substrates. Samples were characterized by in-situ angle resolved x-ray photoelectron spectroscopy (ARXPS) to determine the chemical composition of the surface and also the coverage and thickness of contamination and film layers. The main impurities on the surface were oxygen and carbon. The first two processing techniques had difficulty in either eliminating those impurities or caused additional contamination. Elimination of the impurities was achieved using excimer laser irradiation with a pre-dose of reactive gas. The substrate surface could also be chemically modified in a controlled manner using excimer laser irradiation. Deposition studies of initial sulfur and zinc layers onto the processed substrates determined the temperature during ALE growth should be held at 250-310°C. Uniform coverage of both sulfur and zinc was difficult to obtain, but experiments indicated sulfur adhesion improved with the presence of oxygen, and zinc adhesion improved when oxide or sulfide layers were present on the surface.
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JIN, LIREN. "Nouvelles methodes de preparation des alcenes a partir de sulfones en presence de metaux de transition et etude des mecanismes reactionnels." Paris 6, 1994. http://www.theses.fr/1994PA066389.
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Des travaux precedents du laboratoire avaient montre que l'activation par des sels de nickel de carbanions -sulfonyles conduisait a plusieurs reactions nouvelles ; des differences curieuses de comportement en tert-butyl alkyl et phenyl alkyl sulfones avaient alors ete remarquees. Dans le premier chapitre il a ete montre que la synthese d'alcenes par elimination reductrice avec l'amalgame de sodium dans le methanol des hydroxyalkyl arylsulfones ne pouvait etre etendue aux analogues tert-butylees. La technique de barton utilisant une reduction radicalaire a par contre ete employee avec succes et la stereochimie etudiee. Dans le second chapitre, le comportement des sulfones metalees en presence d'autres sels metalliques a ete etudie. Parmi divers resultats ceux que donnaient les sels de fer ont paru meriter un approfondissement. En particulier le couplage pour donner l'alcene symetrique s'est montre tres efficace particulierement avec les sulfones phenylees. Contrairement au cas du nickel, les sulfones tert-butyl ne se sont pas montrees plus reactives ; mais elles ont donne, quand elles etaient traitees par un exces de buli, une reaction d'elimination qui sera etudiee plus loin. Le couplage de deux sulfones differentes a ete reussi. Apres l'optimisation des conditions, l'application du couplage a des cyclisations a ete etudiee avec des disulfones diversement substituees. Les cycles a 5 et 6 elements sont facilement et efficacement formes, les plus petits moins bien, les grands tres mal. Le troisieme chapitre est consacre a cette reaction d'elimination en presence de fer qui a pu etre rendue assez efficace avec des rendements de l'ordre de 60% qui sont tout a fait inhabituels chez des sulfones non activees. Toutefois l'alcene forme etait assez largement isomerise dans les conditions de la reaction. Par contre, avec du palladium, cette isomerisation a pu etre presque totalement evitee. Divers exemples sont presentes. Une autre reaction a ete observee, a savoir le couplage entre la sulfone et l'organometallique conduisant aux alcenes a m+n carbones. Dans le quatrieme chapitre sont presentees et discutees diverses hypotheses pour rendre compte des diverses reactions rencontrees: couplage homogene, elimination ; couplage avec l'organometallique. Des intermediaires organo-fer ayant ete envisages, une serie d'experiences stoechiometriques ont ete effectuees avec des sulfonylalkyl ferrates. Le couplage homo et le couplage mixte avec le methyle lithium ont pu etre reproduits avec ces sulfones ferrees, ce qui apporte une certaine confirmation aux hypotheses formulees. Par contre le buli donne surtout l'elimination ce qui conduit a faire jouer un role special a l'ion hydrure sur le fer
16
Alamri, Saleh Naeeman O. "Preparation and characterisation of thin film CdS/CdTe solar cells produced by close space sublimation." Thesis, Durham University, 1999. http://etheses.dur.ac.uk/1139/.
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Poquet-Dhimane, Anne-Lise. "Reactivite photochimique de cetones insaturees : preparation et aromatisation d'aryl et heteroarylcyclohexanediones-1,2, preparation et etude stereochimique d'oxetannes insatures." Reims, 1987. http://www.theses.fr/1987REIMS003.
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Sathikge, Ndavheleseni David. "Process for the preparation of cis- AND trans-3,7-Dimethyl 2,6-Octadiene-1-OL from crude sulphated turpentine stream." Thesis, Nelson Mandela Metropolitan University, 2008. http://hdl.handle.net/10948/734.
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As part of CSIR Biosciences’ interest in aroma chemicals, the processing of crude sulphated turpentine (CST) into high value aroma products was investigated. The primary target product, linalool, was obtained from a mixture of α- and β-pinene in four steps. It can be transformed into a wide range of high value added aroma chemicals. Isomerisation of linalool in the presence of a transition metal catalyst furnishes geraniol and nerol. The scientific work described in this report was part of a bigger project aimed at developing innovative processes to manufacture aroma, flavour & fragrance chemicals through beneficiation of industrial waste streams and other raw materials, available locally from the Forestry, Paper & Pulp industries. The evaluation of a process for the preparation of precursor aroma, flavour & fragrance compounds, in particular geraniol and nerol, from locally available raw materials and industrial waste streams, was investigated. Preparation of geraniol and nerol from linalool (ex α-pinene stream) was investigated using acids or organometallic complexes as catalysts for the corresponding isomerisation reaction. The investigation was conducted in an effort to find a less costly process utilising milder conditions than via the conventional cleavage of β-pinene to myrcene under extreme pyrolysis conditions (>650°C). The transformation of linalool to geraniol/nerol using mineral acids was found to be dominated by secondary reactions such as dehydration and cyclisation, resulting in poor product selectivities and yields. On the other hand, organometallic complexes, in particular vanadium-based complexes (e.g. (OV(OBu)3) produced satisfactory results in the preliminary assessment (conversion of 79.8 percent and selectivity of 98.3 percent). A set of statistically designed experiments was carried out on the (VO(BuO)3 + [(Bu)4N+]OH¯) catalyst system where three variables were tested, i.e. substrate concentration, temperature, and catalyst loading. The selected model for conversion was significant with the “Probability > F” being < 0.0001. The most important contributing variable to the model for conversion was temperature i.e. 83.9 percent. Temperature was still the most important variable for the selectivity response at 65.0 percent contribution level. The response surface generated for the selectivity response was flat indicating a robust method within the parameter range selected.
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Jobron, Rochepeau Laurence. "Synthese de fragments de dermatane sulfate. Preparation de derives de l'acide l-iduronique par hydroboration diastereoselective d'exo-glucals substitues." Orléans, 1997. http://www.theses.fr/1997ORLE2014.
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Le dermatane sulfate est un polysaccharide de la famille des glycosaminoglycanes. Il est constitue de motifs repetitifs alternes d'acide l-iduronique et de d-galactosamine. Le ds presente differentes activites biologiques : anticoagulante, antithrombotique, et il joue aussi un role dans la reconnaissance cellulaire. Au cours de ce travail, nous nous sommes interesses a la synthese du disaccharide de base du dermatane sulfate, sulfate en position 2 de l'acide l-iduronique et en position 4 de la d-galactosamine. Dans un premier temps, nous avons realise la synthese de l'acide l-iduronique par inversion de configuration du carbone 5 d'un derive d-gluco suivie d'une oxydation du carbone 6. Cette inversion est realisee par hydroboration diastereoselective d'un exo-glucal substitue. Nous avons ensuite mis au point une methode de preparation de derives de la d-galactosamine a partir du chlorhydrate de d-glucosamine par inversion de configuration du carbone 4 par l'intermediaire d'un triflate. Une etude de la reaction de couplage a ete realisee entre differents donneurs d'acide l-iduronique et des accepteurs a structure d-galactosamine afin de selectionner la reaction qui donne le meilleur rendement et la meilleure selectivite. Le disaccharide ainsi obtenu, est ensuite o-sulfate et deprotege afin de donner le disaccharide de base du dermatane sulfate.
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Belot, Frédéric. "Preparation de derives n-trichloroacetyles de la d-galactosamine et utilisation pour la synthese de fragments de chondroitines sulfate." Orléans, 1999. http://www.theses.fr/1999ORLE2027.
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Les chondroitines sulfates (cs) sont des polysaccharides de la famille des glycosaminoglycanes. Ces molecules sont constituees de motifs repetitifs alternes d'acide d-glucuronique et de n-acetyl-d-galactosamine. Les cs presentent diverses activites biologiques et participent entre autre a certains phenomenes de reconnaissances cellulaires avec notamment une tres grande affinite vis a vis des proteines extracellulaires des lymphocytes nk. Dans le but d'etudier ces proprietes, nous avons envisage la synthese de fragments de chondroitines sulfate de taille et de degre de sulfatation varies. A partir de chlorhydrate de d-glucosamine commercial, peu couteux, nous avons tout d'abord mis au point une synthese efficiente d'unites monosaccharidiques de type d-galactosamine par epimerisation de la position 4. Les derives osidiques obtenus ont ete testes lors de reactions de couplages avec des unites d'acide d-glucuronique. Nous avons determine des conditions operatoires efficaces pour la construction des precurseurs oligosaccharidiques en utilisant notamment des groupements participant en 2 tel le groupement trichloroacetamido et des systemes d'activation tels que les trichloroacetimidates et les thioglycosides. Une voie de synthese generale a ainsi ete degagee et nous a permis de synthetiser avec un bon rendement general des fragments trisaccharidiques et pentasaccharidiques de chondroitines 4- et 6- sulfate.
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Alabbas, Alhumaidi B. "GLYCOSAMINOGLYCAN LYASES IN THE PREPARATION OF OLIGOSACCHARIDES." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5279.
Full textAbstract:
Glycosaminoglycans are heterogeneous polysaccharides that mediate important biological functions. There has been considerable interest in deciphering the precise GAG sequences that are responsible for protein interactions. In fact, several GAG oligosaccharides have been discovered to date as targeting proteins with higher level of specificity. Yet, it has been difficult to develop GAG oligosaccharides as drugs. One of the key reasons for this state of art is that GAG synthesis is extremely challenging and is highly structure-specific. Thus, much of the biology and pharmacology of GAG remains unknown and unexploited to date.
An alternative approach is to prepare GAG oligosaccharides using enzymatic depolymerization of polymeric GAGs. GAG lyases, including heparinases and chondritinases represent powerful tools that can theoretically generate multiple oligosaccharides in parallel. However, it is difficult to implement such procedures with high consistency. Moreover, GAG lyases can digest GAGs down to disaccharides. A priori, non-polymeric GAGs, or alternatively GAG oligosaccharides containing 4 to 10 residues, would be expected to function better as therapeutic agents because they would be more homogeneous and less non-specific than their polymeric precursors.
Thus, we reasoned that immobilization of these enzymes may engineer altered biopolymer processing, which may afford longer oligosaccharides in higher proportions and greater consistency. Heparinase-I and chondroitinase ABC were immobilized on CNBr-activated Sepharose and compared with the free form of the enzyme. Immobilized GAG lyases retained high efficiency of depolymerization over a wide range of pH, temperature and reusability. Most importantly, the immobilized enzyme was found to produce larger proportions of oligosaccharides longer than di- and tetra-saccharides as compared to lyases in the free form.
A two dimensional separation involves size exclusion chromatography followed by reversed phase ion-pairing ultra performance liquid chromatography coupled to electrospray ionization mass spectrometry was employed to separate and characterize oligosaccharide structures. We have identified 40 heparin oligosaccharides, including regular and rare structures ranging from dp4 to dp10 and 39 chondroitin sulfate oligosaccharides in high homogeneity and significant yields. Overall, this technology is likely to offer a simple and cost effective route to preparation of larger amounts of sequences that can be expected to bind and modulate protein function.
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Xie, Haibing. "Preparation of high efficiency Cu2ZnSn(S,Se)4solar cells based on a single-step sulfo-selenization process." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/400605.
Full textAbstract:
Cu2ZnSn(S,Se)4 (CZTSSe) kesterite semiconductors have been proposed as a potential medium to long term replacement of Cu(In,Ga)(S,Se)2 (CIGS) chalcopyrites for sustainable cost-efficient thin film technologies compatible with mass deployment at Terawatt level, being only constituted by elements abundant in the earth crust in contrast with the scarce Indium in CIGS. In this thesis, high efficiency CZTSSe solar cells were fabricated based on a single-step sulfo-selenization process. CZTSSe absorbers with optimal S/(S+Se) ratio, minimized Zn(S,Se) secondary phases in the interfaces, and good crystal quality were achieved through systematically fine tuning of various processing parameters during thermal treatments. The thermodynamic equilibrium of the single-step sulfo-selenization process was also analysed to elucidate the impact of different parameters on the thin films S/(S+Se) ratio. Besides, to address the big challenge of secondary phases in CZTSSe solar cells, an innovative (NH4)2S etching was developed for the selective and effective removal of Sn-(S,Se) secondary phases. This (NH4)2S etching can also passivate the absorber surface and a passivation mechanism was proposed to explain this behaviour. To further improve the efficiency of the CZTSSe solar cells, the CZTSSe/CdS interface was focused and engineered. Na spatial distribution in the CZTSSe/CdS interface region was optimized by a post low temperature treatment process (PLTT), leading to considerable enhancement of the performance of CZTSSe solar cells. An innovative Na dynamics model was established to illustrate the Na in-depth profiles. In addition, Cu doped CdS was investigated to reduce the thickness of CdS while keeping the comparable performance of the kesterite devices, which provides new possibilities to address the Cd concern. Finally, to suppress the CZTSSe/CdS interface recombination and reduce the Voc deficit of the CZTSSe solar cells, a facile wet chemical route based on AlCl3/GaCl3 + thioacetamide solutions were developed. The Voc and efficiency improvement after the chemical treatments can be mainly ascribed to the decrease of interface recombination and shunt paths. A champion CZTSSe solar cell with 9.1% efficiency and FF over 69% was achieved after all these processing optimizations (no ARC). This demonstrates that the single-step sulfo-selenization methodology is promising and feasible for obtaining high efficiency CZTSSe solar cells. selenization methodology is promising and feasible for obtaining high efficiency CZTSSe solar cells.<br>Las Kesteritas (Cu2ZnSn(S,Se)4 o CZTSSe) están llamadas a sustituir a las calcopiritas (Cu(In,Ga)(S,Se)2 o CIGS) como tecnología fotovoltaica de película fina ya que están formadas únicamente por elementos abundantes en la corteza terrestre. En esta tesis, se han fabricado células solares de CZTSSe de alta eficiencia mediante un proceso de sulfo-selenización de un solo paso. Se ha conseguido obtener absorbedores CZTSSe con una ratio S/(S+Se) óptima, un contenido reducido de fases secundarias Zn(S,Se) interfaciales y una calidad cristalina alta a través de la optimización de los parámetros involucrados en los tratamientos térmicos. También se ha realizado un análisis del equilibrio termodinámico durante el proceso de sulfo-selenización para discernir el impacto de dichos parámetros en la ratio final S/(S+Se) de las películas de CZTSSe. Además, se ha abordado la importantísima cuestión de las fases secundarias en las células solares de CZTSSe mediante el desarrollo de un ataque químico con (NH4)2S para la eliminación selectiva de las fases secundarias Sn(S, Se). Se ha comprobado que este ataque químico también tiene efectos pasivantes en la superficie del absorbedor y se propuso un mecanismo para explicar este comportamiento. También se ha llevado a cabo una modificación de la interfaz CZTSSe/CdS optimizando la distribución espacial de Na a través de un proceso post-recocido a baja temperatura que ha conducido a una mejora sustancial del funcionamiento de las células solares. Se propuso un modelo para explicar los perfiles de Na observados. Adicionalmente, se ha investigado el dopaje con Cu de la capa búfer de CdS para reducir su espesor manteniendo un rendimiento similar de los dispositivos fotovoltaicos y minimizar los problemas relacionados con el uso de Cd. Finalmente, se ha desarrollado un tratamiento químico húmedo basado en AlCl3/GaCl3+tioacetamida para reducir la recombinación en la interfaz CZTSSe/CdS mejorando el Voc y la eficiencia de los dispositivos fotovoltaicos. Todo ello, ha conducido a la obtención de una célula solar récord de CZTSSe con un 9.1% de eficiencia y un FF por encima del 69% que demuestra que la sulfo-selenización de un solo paso es una manera viable y prometedora para obtener células solares de CZTSSe de alta eficiencia.
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Ru-Hui, Luo, Wu Wei-Xiao, Cehn De-Yan, and Luo Jian-Xun. "Resource utilization - 152: Preparation and Application of a sulfited Fat-liquor based on Waste beef tallow from Tannery." Verein für Gerberei-Chemie und -Technik e. V, 2019. https://slub.qucosa.de/id/qucosa%3A34257.
Full textAbstract:
Content:
Leather industry is one of many traditional, characteristic and ascendant industries. During the development of Leather industry, the problem of a certain the waste of resources and environmental pollution has been yielded. The waste tallow is one of the problems should be solved quickly. Based on the problem of the waste of resources and environmental pollution form the waste tallow during the leather
industry, act waste beef tallow from tannery as raw material, detection of its physical and chemical properties, de-colorization, deodorization, amidation, esterification and sulfitation were done successively.
Results suggested that the acid value and the saponification value of the waste beef tallow is 45mgKOH/g, 207mgKOH/g respectively. When 6% activated clay was used after 10% hydrogen peroxide, it has the best effect in decolorization and deodorization. When catalyzed by 1% sodium formate, n（ethanolamine）：n （waste beef tallow）is 4:1，the reaction temperature was 130~140oC and time was 2hrs, the acid value and hydroxyl value of the treated beef tallow is 15~30mgKOH/g, about 280mgKOH/g respectively. When the optimum dosage of sodium sulfite is 20%, the fatliquor obtained light yellow and good stability. The sheepskin garment leather fatliquored by this fatliquor is very soft.
Take-Away:
Modification of a sulfited fatliquor based on waste beef tallow.
Application of this sulfited fatliquor.
Other methods of modification of waste beef tallow.
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Ka, Oumar. "Composes 2-6 serigraphies : preparation et caracterisation de cds et cdte." Paris 6, 1988. http://www.theses.fr/1988PA066319.
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Etude des proprietes fondamentales (structures cristallographiques, proprietes transport, luminescence, etc. ) des couches cdte et cds deposees par serigraphie (depot de la pate contenant le semiconducteur desire, sechage puis frittage haute temperature). Application a la fabrication de photopiles solaires en raison de son faible cout
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Flaherty, Terrence Michael. "1. Synthesis of C-glycoside sulfones via oxirane-thirane exchange 2. Preparation of sialic acid derivatives amenable to solid-phase synthesis 3. Conformational analysis of complex polysaccharides." Diss., The University of Arizona, 1997. http://hdl.handle.net/10150/282328.
Full textAbstract:
As part of a program directed toward the synthesis of novel glycosyl transferase inhibitors possessing a sugar-CH₂-SO₂-CH₂-SO₂-CH₂-nucleoside structure, β-C-glycoside sulfones have been prepared with high stereoselectivity. Both glucose and fucose derivatives were prepared. Sulfur incorporation was achieved by free radical addition of thiolacetic acid to exocyclic glycals. As part of a program directed toward the preparation of amide-linked sialic acid oligomers, a strategy was developed for the synthesis of sialic acid derivatives possessing either a free amine or a free acid functionality. Solution phase coupling of these monomers using standard peptide coupling techniques resulted in the synthesis of (1 → 5)-amide linked sialic acid dimers. As part of a program directed toward the identification of novel helical structures, the solution phase conformation of the polylactone of colominic acid was examined by NMR and molecular modeling. The two structures generated from molecular modeling that were consistent with the NOE data were both helical.
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Heimdal, Carl Philip J. "Pulsed Laser Deposition of Zinc Sulfide Thin Films on Silicon : The influence of substrate orientation and preparation on thin film morphology and texture." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-25097.
Full textAbstract:
The effect of orientation and preparation of silicon substrates on the growth morphology and crystalline structure of ZnS thin films deposited by pulsed laser deposition (PLD) has been investigated through scanning electron microscopy (SEM) and grazing incidence x-ray diffraction (GIXRD). ZnS thin films were grown on silicon (100) and (111), on HF-treated and untreated silicon (100) as well as substrates coated with Al, Ge and Au. The ZnS films showed entirely different morphologies for ZnS films grown on silicon (100) and (111) substrates, but a preferred orientation largely independent of substrate orientation, preparation or coating. The films are either wurtzite (W) or a mixture of wurtzite or zinc blende (ZB). The preferred orientation is suggested to be related to the lower surface energies of the W(001) surface, and the ZB(111) surface in a Zn-poor environment. A technique for in-situ removal of native oxide from silicon by laser ablation of a ZnS target was tested and found to remove a significant amount of the surface of the substrates. The reoxidation in air of silicon (100) surfaces was monitored by ellipsometry, and HF-treated substrates were examined by RHEED. The results revealed that HF-treated Si(100) showed signs of rapid reoxidation in air, but this had no visible effect on ZnS film growth compared to untreated substrates.
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COMMENIL, MARIE-GABRIELLE. "Preparation et reactivite de nouvelles sulfines insaturees. Transposition sigmatropique 3. 3 de sulfinamides n-arylees s-ethyleniques. Etude du mecanisme de la reaction." Paris 6, 1995. http://www.theses.fr/1995PA066293.
Full textAbstract:
Les thioaldehydes et thiocetones s-oxydes gamma-ethyleniques et gamma-acetyleniques ont ete synthetisees par transposition sigmatropique 3. 3 de sulfoxydes insatures prepares in situ. La dimerisation a temperature ambiante des thioaldehydes s-oxydes gamma-acetyleniques a donne des 1,2-dithietanes-1,1-dioxydes-3,4-disubstitues. Ils ont ete ensuite transformes, par attaque nucleophile du cyanure de lithium, en olefines de stereochimie z. Le traitement de sulfinates benzyliques et allyliques par le methylate de sodium a permis de former in situ des thioaldehydes s-oxydes alpha-aromatiques ou alpha-ethyleniques qui ont donne naissance a des produits varies: alpha-methoxy disulfures, aldehydes, thionoesters, esters, acetals. Le traitement de sulfines gamma-ethyleniques par des amines aliphatiques primaires a donne des imines. Un grand nombre d'indoles a ete obtenu par transposition sigmatropique 3. 3 de sulfinamides n-aryles s-ethyleniques soit par thermolyse, soit par utilisation de certains acides de lewis ou d'agents alkylants. Des experiences ont ete effectuees afin d'etudier le mecanisme de cette reaction. Nous avons effectue des experiences de croisement entre des paires de sulfinamides afin de savoir si le mecanisme etait intramoleculaire. Nous avons essaye de synthetiser une amino-sulfine analogue a celle proposee pour le mecanisme de la thermolyse des sulfinamides en indoles afin de voir si nous pouvions obtenir un indole par attaque carbophile de l'azote sur la sulfine. Nous n'avons pas pu prouver l'existence de cet intermediaire mais nous avons plusieurs arguments en sa faveur: attaque carbophile d'amines sur des sulfines authentiques, etude du mecanisme de synthese de pyrroles a partir de thiazines qui passerait par une amino-sulfine
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Lemoine, Pascale. "Combinaisons ternaires soufrées formées par l'europium et un second métal : exemples de dérivés de l'europium à valence mixte; synthèse, structures et propriétés physiques." Paris 6, 1986. http://www.theses.fr/1986PA066416.
Full textAbstract:
L'études des combinaisons ternaires soufrées formées par l'europium et un second métal conduit dans de nombreux cas a des composes qui ne contiennent que de l'europium divalent, tels que Eu3Sb4S9, EuLn2S4 (Ln: Dy—Lu, Y) et Eu1,1Bi2S4. . Dans ces trois composes Eu (ii) présente un environnement 8-prismatique et le second métal, un environnement octaédrique. Dans Eu3Sb4S9, le doublet 5s2 non-engagé de Sb (iii) crée de larges tunnels au sein de la structure. Les composés EuLn2S4 ont une structure de type CaFe2O4. Le réseau du composé Eu1, 1Bi2S4 contient de larges canaux partiellement occupés par des atomes d'europium divalent d'environnement 9-prismatique. Dans quelques cas, lorsque le second métal est susceptible de stabiliser partiellement la valence iii de l'europium, des composés à valence mixte sont obtenus, tels Eu2BiS4 et Eu2CuS3 qui contiennent les deux valences de l'europium, mais de façon différenciée par des sites cristallographiques distincts. Dans Eu2BiS4, Eu(ii) a un environnement 7-prismatique, Eu (iii), 7-octaedrique et Bi (iii), octaédrique. Dans Eu2CuS3, Eu (ii) a un environnement 8-prismatique, Eu(iii), octaédrique et Cu (i),tétraédrique. Dans ces deux composés, il existe des feuillets perpendiculaires à l'axe b, de formule Eurs(3) (r = Cu ou Bi). Tous ces composés sont paramagnétiques et semi-conducteurs. Cette étude met en évidence la stabilité de l'état divalent de l'europium dans les sulfures et la nécessité pour obtenir des composes à valeur mixte ou intermédiaire de l'europium, de modifier les conditions d'études, telles que la température et la pression.
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Rannou, Patrice. "Poly(aniline) : synthèse, mise en oeuvre et vieillissement." Université Joseph Fourier (Grenoble ; 1971-2015), 1998. http://www.theses.fr/1998GRE10080.
Full textAbstract:
Ce travail est consacré à la synthèse, la mise en œuvre et le vieillissement d'un polymère conducteur (pc) : la polyaniline (pani). Deux morphologies ont été étudiées : des poudres divisées de pani dopee par l'acide chlorhydrique (pani-hci) et des films de pani dopee par l'acide camphre sulfonique (csa) obtenus par l'évaporation de solutions dans le m-cresol. Dans une première partie, nous présentons la synthèse chimique basse température par voie oxydante de la pani. Le contrôle des paramètres de synthèse a permis de préciser le mécanisme de polymérisation et d'obtenir des polymères de masse moléculaire élevée ou les défauts chimiques du squelette macromoléculaire sont minimises. La deuxième partie présente une revue de connaissances relatives au dopage, à la structure chimique et cristallographique et à l'aptitude à la mise en œuvre de ce pc. Les caractérisations des différentes pani synthétisées ont permis d'étudier les relations structure/propriétés en soulignant les bénéfices apportés par l'amélioration du protocole de synthèse. La définition d'une stratégie de choix des associations pani/dopant/solvant a permis l'obtention de films de pani qui présentent un comportement métallique. La troisième partie de ce recueil est consacrée au vieillissement de poudres divisées de pani-hci et de films de pani-csa. Cette thématique est abordée selon deux aspects : l'identification et l'étude des mécanismes réactionnels qui conduisent à la détérioration de la conductivité ainsi que la prévision du comportement à long terme de la conductivité par la mise en place de tests de vieillissement accélèré.
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Nasri, Habib. "Synthese et caracterisation de porphyrines de fe(ii) et fe(iii) : modelisation du site actif du centre p460 present dans l'hydroxylamine oxydoreductase de la bacterie nitrosomonas europaea." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13149.
Full textAbstract:
Synthese de modeles du site actif du cytochrome p460 a l'etat reduit. Donc synthese et caracterisation d'une serie de complexes (fe(ii) (or)t piv pp)**(-) ou or=ome, oph, ophf::(4), oac; et des complexes fe(iii)cltpivpp, fe(iii)(oac)tpivpp, fe(iii)(so::(3)cf::(3))(h::(2)o)tpivpp
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Wahbi, Mernissi Khalid. "Étude exploratoire du système AG-HG-S : Synthèse de l'imitérite AG::(2)HGS::(2) stabilité thermique, caractérisation électrique et optique." Nancy 1, 1989. http://www.theses.fr/1989NAN10090.
Full textAbstract:
Synthèse par précipitation de solutions aqueuses de nitrates de HG et de AG et de sulfure de NA A 70**(O)C A 10 <OU= PH <OU= 11. Détermination de la stabilité thermique par analyse enthalpique différentielle : décomposition en argentite et cinabre à 215**(O)C. Étude des propriétés électriques entre température ambiante et 185**(O)C: AG::(2)HGS::(2) est un semi-conducteur, mais la conductivité ionique, nulle à température ambiante, atteint 25% de la conductivité totale à 165**(O)C. Analyse de l'absorption optique entre 0,4 et 125 MU M : elle est très proche de celle des constituants et la théorie des groupes permet d'expliquer la variation des pics d'absorption dus aux vibrations du réseau
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Chiu, Yie-Chan, and 邱奕釧. "Preparation and Characteriation of Sulfone Epoxy Monomer and its Nanocomposites." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/51795167761792250501.
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Li, Po-Cian, and 李泊千. "Preparation of Proton Exchange Membrane of Sulfonated Poly(imide- sulfone) for Application in Fuel Cell." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/2znbt9.
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Ko, Tsung-Han, and 葛宗翰. "Preparation of Sulfonated Poly（arylene ether sulfone）Membrane and The Performance for Proton Exchange Membrane Fuel Cell." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/46784282433793118107.
Full textAbstract:
碩士<br>國立臺灣大學<br>高分子科學與工程學研究所<br>99<br>In this studies,novel monomers containing two phenyl groups has been synthesized by bromination of bis（4-fluorophenyl） sulfone, via Suzuki coupling with benzeneboronic acid. The resulting monomers were converted to the corresponding sulfonated monomers having two pendent sulfonic acid groups.
Aromatic nucleophilic substitution （SNAr） polycondensation using the disulfonated monomers provided sulfonated poly（arylene ether sulfone） polymers P1 and P2.
Flexible and tough membranes having high mechanical strength were obtained by solution casting of all two series of polymers.
The polymers with two pendent sulfonic acid groups had high proton conductivities in the range of 57-183 mS/cm for P2-xx at 70°C, respectively. The methanol permeabilities of these polymers were in the range of （0.35-1.368 cm2/s）, which is lower than Nafion （1.45 cm2/s）.
In proton exchange membrane fuel cell test, P2-70 membranes showed the good cell performance. This study suggests that the P2 membranes also have high potential for direct methanol fuel cell application.
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Tsai, Po-Chung, and 蔡博仲. "Preparation and Application of Sulfonated Poly(arylene ether sulfone)/Heteropolyacid (H3PW12O40) Composite Membranes for Proton Exchange Membrane Fuel Cell." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/74561716792696806057.
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碩士<br>國立臺灣大學<br>化學工程學研究所<br>100<br>In this study, SPAES/HPA composite membranes were prepared for proton exchange membrane fuel cell (PEMFCs). Phosphotungstic acid, one kind of heteropolyacids (HPA), which was added into polymer materials made from sulfonated poly(arylene ether sulfone)s (SPAES) with pendent sulfonic acid was studied for being applied to H2/O2 PEMFC. This kind of random copolymer side-chain sulfonated poly(arylene ether sulfone)s was prepared by aromatic nucleophilic substitution（SNAr）polycondensation using the hydrophobic monomer 4,4''-difluorodiphenylsulfone (S), 4-(4-(4-Methoxyphenoxy) phenoxy)phenol (DH-3AE) and hydrophilic monomer bis[4-fluoro-3-（4-sulfophenyl）phenyl] sulfone (SPDS) all that we had successfully synthesized. SPAES/HPA composite membranes were prepared by casting procedure, using SPAES polymer solution and phosphotungstic acid mixtures. The physical and chemical properties include thermal properties of the membrane, water uptake, dimensional stability, proton conductivity, morphology and fuel cell power performances were measured and discussed in our study. The experimental results found that adding inorganic phosphotungstic acid into this polymer solution showed a higher water uptake compare with the native polymer materials. It was also found that it could obviously improve proton conductivity as well as performances.
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SUNG, TZU-SHING, and 宋慈馨. "Preparation of Heteropoly acid / Sulfonated Poly(arylene ether sulfone)s Composites Proton Exchange Membranes for Application in Fuel Cell." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/26m774.
Full textAbstract:
碩士<br>國立雲林科技大學<br>化學工程與材料工程系<br>106<br>In this study, firstly, poly(arylene ether sulfone)s was sulfonated by using fuming sulfuric acid. Secondly, sulfonated poly(arylene ether sulfone)s (SPAES) was prepared by aromatic nucleophilic substitution （SNAr） polycondensation. The degree of sulfonation was controlled by adjusting the percentage of monomers.
Then, phosphotungstic acid and tungstosilicic acid were added into SPAES solution in order to synthesize proton exchange membrane by casting. The HPA/SPAES composites membranes possess excellent dimensional stability and high proton conductivity.
The chemical structures of SPAES were identified with both FT-IR and 1H-NMR. The membrane showed glass transition temperature (Tg) around 200℃, main-chain degrading while the temperature increased to 380℃-450℃ under purging nitrogen condition. The proportion of Freezable and Non-freezable water were known by the distribution test of water. The internal structure and section of membrane were observed by both TEM and SEM. We use EDS to locate phosphotungstic acid and tungstosilicic acid. Then, the physical properties and proton conductivity of the membrane prepared by Heteropoly acid / Sulfonated Poly(arylene ether sulfone)s were measured to evaluate the feasibility.
The experimental results found that adding phosphotungstic acid and tungstosilicic acid into Sulfonated poly(arylene ether sulfone)s solutions could improve the proton conductivity effectively and raise the test temperature above 90 °C.
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CHEN, PO-WEI, and 陳柏瑋. "Preparation and Characterization of Proton Exchange Membrane Composite of PEG Modified Sulfonated Polyfluoroether Sulfone and Different OMMT Applied to DMFC." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/f82upv.
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碩士<br>南臺科技大學<br>化學工程與材枓工程系<br>105<br>In this study, using the synthesized PEG (Polyethylenglycol) modifier composite membrane to fabricate MEA (Membrane Electrode Assembly) and evaluating the performance of the single cell. The synthesis experiment will be conducted by condensation polymerization of hydroquinone 2-potassium sulfonate, hexafluoro-bisphenol A, 4-fluorophenyl sulfone and PEG. We have already synthesized copolymer without PEG and find out that it has a poor water uptake and proton conductivity property. We expect that to introduce a hydrophilic polyethylenglycol (PEG) will increase the water uptake ratio of the resultant copolymer. After the purification of the above synthesized polymer products, and use the FT-IR, 1H NMR to confirm the polymer. The ion exchange capacity of the polymer was 1.03mmol/g. In addition , the high methanol permeability can be reduced by the adding of organically treated nanomontmorillonite (OMMT) into the polymer matrix. The copolymer will well-mixed with OMMT to make a composite and it will be used to produce a low methane penetration proton exchange membrane. There were three commercial modified montmorillonites, TSA (trimethyl steary ammonium), DDA (dimethyl dialkyl amine) and MDHTA (methyl dihydroxyethyl hydrogenated tallow ammonium) were chose and added into previous copolymer respectively. After 4% modified montmorillonite added, the highest water absorption of the three composites is 20%. Besides the contact angle is slightly decreased after the addition of OMMT. By the electron microscope it can be clearly observed stereoscopic sheet structure, and the other test show that a proton exchange membrane with a methanol crossover of 2.03×10-9cm2/s and a selectivity ratio of 1.672×107 S×s/cm3 were obtained by adding 4wt% of MDHTA-MMT. Three OMMT modified MEAs being conducted a single cell performance tests, the addition of TSA-MMT composite membrane has an open circuit voltage of 0.637V, and the maximum power density is 15.89 mW. After 3 hours endurance test, it can still maintain an open circuit voltage of 0.623V, and a highest power density of 12.15mW.
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HUANG, JING-YU, and 黃靖雨. "Preparation of Proton Exchange Membranes of Sulfonated poly(arylene ether sulfone)s through Low Temperature Decal Transfer Method for Application in Fuel Cell." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/2m9wsw.
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碩士<br>國立雲林科技大學<br>化學工程與材料工程系<br>105<br>In this studies, Aromatic nucleophilic substitution （SNAr） polycondensation using the disulfonated monomers provided (Sulfonated poly(arylene ether sulfone)s，SPAES) have been synthesized as the proton exchange membrane used in polymer electrolyte fuel cell. The dimensional stability and proton conductivity are good for these highly functional SPAES. The SPAES proton exchange membrane is made into MEA by low temperature decal transfer to give it a good battery performance.
The chemical structures of these highly functional SPAES were identified with FT-IR and 1H-NMR. The membrane properties of water uptake, dimensional stability, oxidative stability, proton conductivity, thermal properties and microstructures. The fuel cell power performances were investigated to check the viability of the proton exchange membrane prepared by sulfonated poly(arylene ether sulfone)s.
The results show that the proton conductivity of SPAES can reach 100.75 mS / cm, and the interface of MEA can be effectively reduced by FE-SEM and has good dimensional stability and thermal stability. At the highest sulfonate The content of the P50 SPAES proton exchange membrane also has good discharge performance.
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Tang, Tzu-Piao, and 唐自標. "Preparation and Characterization of Zinc Sulfide based Phosphors." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/94479935143596786583.
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博士<br>大同工學院<br>材料工程研究所<br>87<br>The objective of this paper is to discuss the preparation of ZnS phosphor powder and their firing atmosphere. In this research, several controlling factors that could affect the phosphor''s luminescence characteristics, such as firing temperatures, atmosphere, firing time and the selection of flux and dopant, were evaluated.
When prepare the ZnS phosphor powder using solid-reaction firing, it is important to control the distribution of additives. However, the luminescence characteristics of ZnS is dependent upon the firing atmosphere, temperature and time.
It is found that the luminescent property of host lattice changes along with amount of hexagonal phase in ZnS phosphors. The higher the firing temperature, the higher the amount of hexagonal phase can be found in ZnS phosphor. Also, its wavelength will shift toward long wavelength region (449nm R453nm) with higher luminescent intensity. For those content less hexagonal phase, its wavelength will move toward short wavelength region (459nmR 457nm) with lower luminescent intensity. After washing with water, the wavelength of ZnS phosphor will shift to short wavelength region (449nm) and shows better luminescent effect and higher intensity.
Blue ZnS phosphors with (Ce) dopant can be formed in inert atmosphere and is known as 5dR4f host lattice luminescence. With the addition of flux, its luminescence increase and wavelength is in the ranges between 446nm-480nm. After washing, the higher the Ce residue in ZnS phosphors, the better the luminescence. But, the remained Chlorine and Sodium were also reduced and affect its luminescence. For ZnS phosphors formed at higher temperature, the loss of Ce can be reduced after washing, and thus, help the formation of defect and amount of ions. Under the equivalent of ionic hole and number of ions, it will increase the luminescence intensity. It was found that ZnS phosphor has the highest luminescence intensity when firing at 950℃ with 0.2 Ce mol% addition.
Red ZnS phosphors were fired under reducing atmosphere with the addition of Sm+3. ZnS host lattic self-activation luminescence center was found disappeared under reducing condition. When Sm2O2S exists, it has better Sm characteristic luminescence due to Sm ions transfer between 4f-4f orbital and move from 4G5/2 to 6H5/2、6H7/2、6H9/2. If the stable Sm2O3was formed, the self-activation luminescence center will appear. The role of the addition of flux (LiCl) can determine the exciting energy transformation (photoionization) which will then result in either self-activation or Sm characteristic luminescence. A certain amount of LiCl addition can react with Sm compound and increase luminescence intensity. The optimal conditions to form ZnS phosphors with red characteristic luminescence is found at 1050℃ reducing atmosphere and LiCl：2.0 mol％，Sm +3：0.30mol%.
The Tb characteristic luminescence was not found in ZnS phosphors when firing under reducing atmosphere with the additon of Tb. This is believed to be due to the Tb characteristic luminescence can only be emitted from5D4→7F6（487nm）、7F5（546nm）、7F4（588nm）、7F3（617nm）green luminescent materials. In order to produce Tb characteristic luminescence, the Tb need to be evenly distributed with the addition of flux. The optimal conditions for this process are 1050℃ firing temperature, reducing atmosphere, 0.5mol% of Tb and KF which is found need to be added three times as much as Tb.
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Chen, Jia-Sheng, and 陳佳聖. "Preparation of Tin(II) Sulfide Nanoparticles and Characterization." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/31922701186207790515.
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Chiang, Kai-Peng, and 江凱焩. "Preparation and application of chitosan/chondroitin sulfate nanoparticles." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/04236613018809843040.
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碩士<br>國立成功大學<br>材料科學及工程學系碩博士班<br>94<br>In this study, chitosan(CTS) and chondroitin sulfate(ChS), two poly-electrolytes, were used to form nanoparticles through electrostatic force by a step dropwise method. These particles were evaluated their application for drug delivery of 5-fluorouacail(5-FU). According to FTIR analysis, there exists the bonding of NH3+ of CTS together with COO- and OSO3- of ChS in the complexes. It demonstrates that the complexes are formed by electrostatic force of these two poly-electrolytes. Then, it is observed the influence of the concentration ratio of CTS/ChS, reaction pH value and the viscosity molecular weight(Mv) of CTS on the particle size and zeta potential of CTS-ChS particles. It is found that the CTS-ChS particles with average size of 145 nm could be obtained with the concentration ratio of CTS and ChS of 4:3, reacted in pH 3 condition and the Mv of CTS being 80 kDa.
The in-vitro release profiles of the 5-FU are established in phosphate buffer solution (PBS) pH=7.4 at 37℃. Encapsulation efficiency (EE) of drug for different mixing procedure of 5-FU/CTS with ChS or 5-FU/ChS with CTS is compared, the later shows a higher EE up to 42.5±1.1%. The influence of the amount of initial drug on the EE is shown that the highest EE up to 70.4±2.1% could be obtained for the addition of 10 mg. In addition, as the pH value or Mv of CTS increases, the EE of 5-FU would increase. The result of drug release shows that whether the Mv of CTS is 600 kDa, 200 kDa or 80 kDa, 5-FU/CTS-ChS particles follow two steps Higuchi model for the drug release kinetics. Besides, the release rate and release amount of 5-FU increase for the lower Mv of CTS.
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chun, Cheng-yu, and 鄭伃君. "Preparation of Zinc Sulfate use Industrial Copper Dust." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/67560626884457746576.
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碩士<br>國立中央大學<br>環境工程研究所在職專班<br>102<br>Abstract
There is lack of natural resources and mineral resources, especially scarce metal in our country. With the growth of economic development, Taiwan has increased the consumption of metal gradually in these decades, and has to rely on import of these kinds of resources in order to obtain the necessary support of metal for economic development.
The current industrial copper dust is curing or chemical treatment. Therefore, to satisfy with both government policy development and needs of economic development, this study gathers dust resources into product reuse, and explores the different experiments operating parameters, seeking for the optimum operation conditions.
The results show that zinc content of the flue dust collected in this study has an average of 57.25 percent, an average of 5.38 percent copper content. The raw materials evaluates best ratio in the flue dust: Sulfuric acid: water as 1:2:3, 30N sulfuric acid concentration 150rpm for the speed when evaluating stirring, 180 minutes for the solvent extraction time, and 40 ℃ are the best solvent extraction conditions. Vacuum concentration crystallization is the best that bring together all the advantages and this method has advantages of short crystallization time and less energy consumption.
In SEM-EDS analysis, it show that the elements of its composition under different conditions are zinc, oxygen, sulfur. All samples were analyzed by XRD and the result show that they are prepared as zinc sulfate monohydrate. After TEM and BET characterization, it is confirmed as a perfect crystal grain in good shape. Economic analysis of calculating the return on investment estimates the recyclable life of adding this production line is 1.45 years. The study is currently not applicable to the real field, because it still relies on many undergoing follow-up studies.
Keyword：industrial copper dust collection、chemical eluviation、Crystallization、Zinc Sulfate、Economic Benefit Analysis
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Lin, Chun-Ting, and 林峻廷. "Preparation, Luminescence and Encapsulation of Inorganic Sulfide Phosphors." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/53ckbx.
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碩士<br>國立交通大學<br>應用化學系分子科學碩博士班<br>105<br>Abstract
In combination with blue light emitting diode(LED), green-emitting SrGa2S4: Eu2+ and red-emitting SrS: Eu2+can be used to fabricate white-light. Sulfide phosphors suffer from material instability such as oxygen, moisture and even ultraviolet radiation damage and generate low efficiency, aging and degradation, which is considered as serious drawback in application.
This research investigates encapsulation of SrGa2S4: Eu2+ and SrS: Eu2+ with SiO2, poly(methyl methacrylate) (PMMA) and polyvinylpyrrolidone (PVP) by using sol-gel method. The encapsulated phosphors were then characterized using X-Ray diffraction (XRD), luminescence and FTIR spectroscopy, FETEM and SEM microscopy, and integrating sphere to determine quantum efficiency, CIE chromaticity, and microstructures. Investigation results indicate that both SrGa2S4: Eu2+and SrS: Eu2+can be successfully encapsulated with SiO2,PMMAand PVP with thickness ranging from 26-71 nm, 170-770 nm and 250-720 nm, respectively, upon encapsulation. Our results indicate that the luminescence intensity of encapsulated sulfides decreases upon encapsulation. The electrical conductivity of encapsulated sulfides was found to decrease as compared to those without encapsulation with the same dipping time.
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LIN, YI-SHIN, and 林益新. "Preparation of cyanophycin-dextran and cyanophycin-dextran sulfate conjugates." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/26870621461778639902.
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碩士<br>國立臺灣科技大學<br>化學工程系<br>103<br>Cyanophycin, a non-ribosomal synthesis protein, can be produced by recombinant Escherichia coli. The polymer consists of a polyaspartic acid backbone with arginine and lysine as a side chain. Dextran is a polysaccharide composed by glucose molecules, and is capable of good hydrophilicity and biocompatibility. Dextran sulfate is capable of good biodegradability and it has biocompatible polyanion as heparin. Its structure is a polysaccharide which has negatively charged sulfate groups. In this study, we prepared differnet ratios of cyanophycin - dextran/ cyanophycin - dextran sulfate composite 3D scaffolds by cross-linking reaction with glutaraldehyde. We expect that scaffolds have their properties.
We modified the dextran and dextran sulfate by different method, and then the two polymers which had been modified were grafted with cyanophycin by chemical bonding in order to make more biocompatible polymer. We made the dextran have more aldehyde group in order to make it graft with cyanophycin. We except that the grafting ratio is up to 10%. We also made the dextran sulfate have carboxyl group in order to make it graft with cyanopycin. The graft information of cyanophycin - dextran sulfate was determind by TNBSA. We detected the toxicity of the two polymers (cyanophycin-dextran and cyanophycin dextran sulfate) by the MTT assay. Finally, we mixed cyanophycin-dextran and cyanophycin dextran sulfate in different weight ratio, and then the mixed polymer solution were cross-linked with glutaraldehyde to form 3D scaffold.
The result showed that the cyanophycin-dextran had the grafting ratio about 10%. We confirmed that the cyanophycin-dextran sulfate had grafted with each other. We had information that cyanophycin-dextran and cyanophycin-dextran sulfate was not toxic from MTT assay.
We measured the volume of 3D scaffolds which have different contain of cyanophycin-dextran and cyanophycin-dextran sulfate. The data showed that if cyanophycin-dextran sulfate contains large proportion in the scaffold, the volume will be relatively small. The swelling ratio of scaffolds showed that each scaffold had massive swelling ratio in short time and it also showed that cyanophycin-dextran had more influence than cyanophycin-dextran sulfate on the swelling ratio. The SEM data showed that both surface and cross section had pores.
In conclusion, the scaffold had good hydrophilicity. The scaffolds will be good for cells to migrate because of their proper pore size. We expect that it can use in cell culture.
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Chen, Ai-Ling, and 陳艾鈴. "Preparation and Characterization of Chondroitin Sulfate and Polycaprolactone Copolymers." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/51907207289944284576.
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碩士<br>高雄醫學大學<br>化學系碩士班<br>95<br>Polycaprolactone (PCL) is one of the polyesters, which are biodegradable due to the ester bonds in the structure that can be degraded by enzymes in human body. PCL has been proven to be a biocompatible material and high permeability for drugs. Thus we used it in our drug delivery system.
PCL is highly hydrophobic and crystalline. In order to promote the drug-release efficiency, we use chondroitin sulfate (CS) to compensate these characters. CS, a natural polymer in the mammals’ extracellular matrix (ECM), is highly hydrophilic and performs a good biocompatibility. The drug carriers made of CS is expected to increase the hydrophilicity and avoiding to be recognized by the immune system in human body.
First, we modified the PCL and CS structure with double bond, and copolymerized the two materials through the free radical reaction. The copolymers were named as CXPY, X was the feed weight ratio of CS and Y was the feed weight ratio of PCL. The copolymers were analyzed with Fourier transform infrared spectrophotometer (FT-IR), 1H-NMR, gel permeation chromatography (GPC), differential scanning calorimeter (DSC). Then we prepared the micelles with copolymers through a simple emulsion. With the fluorescence probe techniques, we calculated the critical micelle concentration (CMC) was in the range of 1.17×10-4-8.86×10-3 mg/ml. Under transmission electron microscope (TEM), the profiles of the micelles were spherical. By dynamic light scattering (DLS), the size of micelles were all under 300 nm, and didn’t aggregate nor change in 15 days in double deionized. water.
In the drug-loading test, we used bovine serum albumin (BSA) as a model protein. The entrapment efficiency was above 80 %. In the drug-release test, the micelles released a few BSA content with adding esterase or without any enzymes. In contrast, the micelles released 80 % BSA in 50 days in the presence of both esterase and chondroitinase ABC.
In cell experiment, we chose the MTT assay to examine biocompatibility of the copolymers, which didn’t show remarkable cytotoxicity. The BSA was labeled with FITC (FITC-BSA) in order to examine the cellular uptake of the FITC-BSA-loaded micelles. We used the FITC-BSA as a control. With the use of confocal microscopy, the internalized micelles were more than the control.
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Chen, Wen Pen, and 陳文彬. "Preparation and characterization of Chitosan and Chondroitin Sulfate complexes." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/86742037341797419384.
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碩士<br>高雄醫學大學<br>化學系碩士班<br>90<br>A highly deacetylated chitosan (ChI) was used to prepare its polyelectrolyte complex with chondroitin sulfate (ChS). The ChS/ChI complexes were obtained at different pH values as well as at various weight ratios of ChS/ChI in feed. The complexes were separated from the supernatants by centrifugation. The ChS/ChI molar ratios of complexes were determined by (13C) solid state NMR and by EA. The interactions between ChS and ChI were studied by Fourier transfer infrared spectroscopy (FT-IR). The equivalent ChS molar ratios of complexes were within 0.47~0.55. Thus, the highest yields of complexes were obtained at the equivalent feed molar ratio of —OSO3- and —COO- with —NH3+. The thermal stability of the complexes was studied by DSC and TGA, the results indicated that ChS-6-5 had better thermal stability than other samples. GPC test represented that ChS-6-5 had the strongest interaction between ChS and ChI in PPT. Zeta-potential was used to analyze the surface charge of complexes, and the results showed were all positive values, indicating that ChI was coacervated on the surface of complexes. Simulated gastric fluid (SGF, pH=1.2), intestinal fluid (SIF, pH=7.4), phosphate buffer saline (PBS, pH=6.8) and deionized water were used as the swelling media. Most of the PPTs dissolved in SGF within 2h, except ChS-8-3. Moreover, the ChS-8-3 could retain in SGF over 2 days after cross-linked with glutaraldehyde (GA).
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Chang, Tsung-hsun, and 張琮珣. "Preparation of Zinc Sulfide Nanostructures by Using Chelating Polymer Templates." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/39335359218283838328.
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碩士<br>國立成功大學<br>化學工程學系碩博士班<br>97<br>A simple synthetic route for preparation of luminescent and magnetic nanocomposite materials is disclosed. This method comprises providing chelating group-containing polymer templates, and producing nanoparticles on the surface of said polymer template. Various kinds of nanoparticles can be synthesized on polymer templates with electroless plating, ultraviolet irradiation, gas phase and liquid phase chemical precipitation methods. This approach is suitable not only for the preparation of semiconductor nanoparticles but also other nanoparticles, especially those that can be prepared from the reduction of an appropriate metal ion-polymer complex.
In this study, ZnS nanostructures were prepared by using poly(BA-co- GMA-co-GMA-IDA) (PBGG-I) copolymer membranes as template. PBGG-I membranes were synthesized by soap-free emulsion copolymerization of n-butylacrylate (BA), glycidyl methacrylate (GMA) and 2-methacrylic acid 3-(bis-carboxymethylamino)-2-hydroxy-propyl ester (GMA-IDA). GMA-IDA chelating groups within the copolymer were the coordination sites for chelating Zn2+, at which nanosized ZnS nanocrystals were grown by the wet method (Na2S) and the dry method (H2S). The morphology of ZnS nanocrystals were observed by SEM. By the wet method, ZnS nanorods or nanorod-bundles were prepared. On the other hand, ZnS nanoparticles or nanorods were observed by using the dry method.
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Zhong, Yong-Qing, and 鍾永清. "Preparation of Heparan Sulfate Oligosaccharide Library Using One-pot Strategies." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/30953725588856826243.
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博士<br>國立清華大學<br>化學系<br>101<br>This dissertation describes the synthesis of twelve heparan sulfate disaccharides for FGF-1 binding assay and the preparation of four hexasaccharides by one-pot strategy.
Chapter 1 introduces the cell surface glycoconjugates and explains the biological function of heparan sulfate. The literature reports for the preparation of oligosaccharide skeletons by stepwise methods or one-pot glycosylation and the synthesis of heparan sulfates that bind with FGF-1 and other proteins are summarized in Chapter 2 and Chapter 3, espectively. Chapter 4 describes the retro-synthetic plan for the twelve heparan sulfate disaccharides.
Chapter 5 describes the synthesis of two monosaccharides for generating twelve heparan sulfate disaccharides, including the optimization of 1,6-anhydro-L-idopyranose preparation. In Chapter 6, glycosylation of two prepared monosaccharides was carried out to yield the disaccharide skeleton followed by several functional group transformations to produce the common intermediate 279. The final twelve heparan sulfate disaccharides were synthesized by the subsequent deprotection and sulfonation strategies. Chapter 7 introduces two binding tests between heparan sulfate disaccharides and FGF-1 by ITC and protein crystallization. The information helps us understand the relationship between disaccharides and FGF-1 more than before.
Chapter 8 describes the difficulty in synthesizing heparan sulfate oligosaccharides and the reason of using one-pot glycosylation and new relative reactivity value to prepare oligosaccharide skeletons. In Chapter 9, various monosaccharides for measuring new relative reactivity values are synthesized. Based on these values, the relationship between reactivity of glycosyl thiol and leaving group is explained. Chapter 10 describes the retro-synthetic plan for four heparan sulfate hexasaccharides. Chapter 11 relates with the synthesis of four heparan sulfate hexasaccharide skeletons. The preparation of four final hexasaccharides is summarized in Chapter 12.
The conclusion of the present synthetic work is summarized in Chapter 13, a total synthesis of twelve heparan sulfate disaccharides and four hexasaccharides. Chapter 14 provides the detailed experimental procedure and physical data of the compounds synthesized herein.
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Cheng, Hao-Yu, and 鄭皓宇. "Preparation and Characterization of Cadmium Sulfoselenide and Cadmium Sulfide Thin Films." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/14536262162547093596.
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碩士<br>國立臺灣大學<br>化學工程學研究所<br>99<br>Cd(S,Se) thin films were successfully synthesized on the glass substrates via the CBD method followed by a selenization process. The contents of selenium ions in Cd(S,Se) films were increased with increasing reaction temperatures and duration. The adjustable band gap values of Cd(S,Se) films were controlled with the selenium-ion contents. All the synthesized films exhibited the n-type characteristics via Hall effect measurement. The carrier concentration and the conductivity were significantly promoted with the selenization process.
CdS thin films were successfully synthesized on the glass substrates via the CBD route without using ammonia. The obtained films were demonstrated to exhibit a high transmittance via UV-Vis analysis. The particle sizes on the surface of the prepared films were dominated by the condition of deposition process.
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Lai, Shiau-Fen, and 賴曉芬. "Preparation and Characterization of Methacrylate Chondroitin Sulfate – co –Polyethylene Glycol Diacrylate Hydrogel." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/68426732943523969296.
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碩士<br>高雄醫學大學<br>醫藥暨應用化學系碩士班<br>94<br>The goal of this work was to utilize the colon-specifically degradable polymer，chondroitin sulfate (CS)，prepare hydrogel for a protein delivery Polyethylene glycol diacrylate (PEG-DA) with the different molecular masses of PEG (1K, 2K, and 4K g/mol) and methacrylated chondroitin sulfate (CS-MA) with 28 mol% of methacrylated substitution onto chondroitin sulfate were first prepared. Three hydrogels with different ratios between PEG-DA and CS-MA were synthesized and their effects on weight loss, swelling, compression modulus, and controlled release of bovine serum albumin were carried out. We found that about 20 - 30 weight loss were obtained and slightly decreased with the increase in molecular masses of PEG after water extraction of these hydrogels. The swelling percentage all went up with the increase in the contents of CS-MA in hydrogels using three different molecular masses of PEG and especially pronounced in the PEG1K hydrogels. The degree of swelling were within 10-20 times. In an example of PEG-DA with the PEG2K, the compression modulus and effective crosslinking density increased with the ratio increase of CS-MA to PEG-DA. In in vitro drug released studies using FITC-BSA as a model drug. The results showed that the release rates of CS-MA-co-PEGDA hydrogel went hand-in-hand with the swelling data. The high swelling percentages in PEG-DA with lower molecular weight of PEG led to the higher release rate of FITC-BSA. However, the effect of the ratio between CS-MA and PEG-DA on the release rate of FITC-BSA was unpronounced.