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1
O'Brien, Stephen. "The chemistry of mesoporous materials." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390532.
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Patel, Harish M. "Biomimetic templating in materials chemistry." Thesis, University of Bath, 1998. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390225.
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Thomas, Paul Matthew. "Structural chemistry of organically templated materials." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670194.
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Strange, Gregory Alan. "RESPONSIVE MATERIALS VIA DIELS-ALDER CHEMISTRY." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/710.
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The corrosion of infrastructure imposes a significant monetary cost, and at times human cost, upon society. Methods to improve corrosion resistance of materials are described herein which utilize the reversibility of the Diels-Alder reaction to impart thermal responsiveness upon materials. Such stimuli responsiveness can potentially play a role in self healing properties which lead to reduced cracking and thus increased corrosion protection.
Reversible Diels-Alder chemistry was utilized to manipulate the surface energy of glass substrates. Hydrophobic dieneophiles were prepared and attached to glass slides and capillaries to yield a nonwetting surface. Thermal treatment of the surfaces cleaved the Diels-Alder linkage, and resulted in the fabrication of a hydrophilic surface. Preliminary analysis utilized contact angle (CA) measurements to monitor the change in surface energy, and observed a hydrophilic state (CA - 70±3°) before attachment of the dieneophile to a hydrophobic state (CA - 101±9°) followed by regeneration of the hydrophilic state (CA - 70±6°) upon cleavage of the Diels-Alder linkage. The treatments were then applied to glass capillaries, with effective treatment confirmed by fluid column measurements. Patterned treatments were also demonstrated to provide effective fluid flow gating.
Reversible Diels-Alder linkages were incorporated into polymer thermoset binding resins in order to provide a means by which a crosslinked thermoset could undergo stimuli responsive reversible crosslinking. The binder systems which were utilized included two types of amine curing agents, polydimethylsiloxane (PDMS) and Jeffamine® polyetheramines (PEA), and two types of epoxy resins, EPON resin based on diglycidyl ether of Bisphenol-A and epoxidized soybean oil. Various dienes and dienophiles were employed to functionalize the selected binder systems and were met with various degrees of success. The synthetic technique which proved to be the most promising was the Diels-Alder modification of the epoxidized soybean oil.
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Skipworth, Carnetta. "Teachers' Resource for Materials and Environmental Chemistry." TopSCHOLAR®, 2003. http://digitalcommons.wku.edu/theses/568.
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In many secondary education chemistry classrooms, teachers have a difficult time introducing chemistry topics in a way that will be interesting to the high school student. The development of a materials and environmental chemistry teacher's manual will help teachers introduce a variety of selected topics in an interesting fashion to the students. This manual focuses on the subjects covered for freshman and sophomore level students. The manual uses five separate experiments to introduce topics such as the electromagnetic spectrum and solubility. The five experiments include a test on tennis shoe stiffness and energy dissipation ability, pesticides in water, grease in vent hoods, concentration of salicin in willow, and a paint adhering test on a vehicle bumper. The manual introduces several chemistry concepts by relating the subject to projects that the students can understand because they are useful to society and the environment. By presenting the material in this manner, students should be able to focus on the specific concepts longer, thus understanding the concepts better. Some of the lessons cover a topic that is required by the American Chemical Society (ACS) for postsecondary education materials chemistry classes. The inclusion of these topics will increase the knowledge of future chemistry students in an area that will be required at multiple postsecondary education institutions. Each experiment topic includes background information, teacher information, lesson objectives, ACS topic and/or experimental subject covered, lesson, definitions, supplements, transparencies, and a worksheet.
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Sharma, Amit. "Materials chemistry and magnetoresistance of Sr₂FeMoO₆." Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415224.
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Tasker, Simon. "The surface chemistry of polymeric bioseparation materials." Thesis, Durham University, 1996. http://etheses.dur.ac.uk/5333/.
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The aim of this thesis was to test existing theories concerning biocompatibility of polymeric materials, and in the process to try and identify the major factors which pertain to their use as bioseparation matrices. The surface chemistry of cellulose and poly(tetrafluoroethyIene) based bioseparation materials have been examined. We have been able to demonstrate a direct link in the case of the cellulose materials between the crystallinity and the accessibility of the hydroxyl groups which are the primary sites of functionalization. In addition, the effect of processing conditions on the pore structure of an amorphous cellulose matrix was demonstrated and this has been shown to have a direct consequence for the protein binding characteristics of the material. The functionalisation of PTFE has been achieved by reaction with sodium naphthalenide, which lead to the defluorination of the PTFE surface and the formation of a unsaturated carbonised layer containing oxygenated functionalities. The reaction has also been shown to alter the morphology of PTFE membranes as evidenced by AFM analysis. In the case of powdered PTFE we observed the formation of a microporous layer, however this was found to revert back to a fluorinated layer with gentle heating. A novel insight in to the defluorination reaction was obtained using the bombardment of PTFE and PVDF with a Na atom beam under ultra-high vacuum conditions. This demonstrated the single valence electron mechanism of the reaction and also showed the formation of NaF at the surface of the polymer. The formation of CF(_3) groups was attributed to the nucleophilic attack of fluoride ions from molecular NaF species formed at the initial stages of the reaction.
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Kong, Chang Sun. "A materials informatics approach for crystal chemistry." [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3369850.
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Gonçalves, Rogéria Rocha [UNESP]. "Preparação e caracterização de filmes óxidos contendo componentes opticamente ativos." Universidade Estadual Paulista (UNESP), 2001. http://hdl.handle.net/11449/105805.
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goncalves_rr_dr_araiq.pdf: 4816799 bytes, checksum: 0ead4e8520f4bac562bdbb2a9a71bc5c (MD5)<br>Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)<br>A preparação dos sistemas dopados com ions lantanídeos (Eu e Er): SnO2, HfO2, HfO2 disperso em matriz híbrida, SiO2-HfO2, Ta2O5, Ta2O5 disperso em matriz híbrida, através da metodologia sol gel, foi objetivo desta tese . São apresentados resultados para suspensões coloidais, sólidos (géis, xerogéis e pós) e filmes preparados por spin coating. Suspensões coloidais de SnO2 dopados com até 2% em mol de íons Eu e Er foram preparadas a partir da redispersão, em meio aquoso básico, de nanoparticulas com a superfície modificada. Diâmetro médio de 4 e 6 nm foram observados para os compostos dopados e puros respectivamente, através de espalhamento de luz e microscopia eletrônica de transmissão. Os compostos apresentam nanocristalitos, estrutura cassiterita. O íon Eu3+ ocupa dois diferentes sítios de simetria na matriz SnO2. Um referente ao ion Eu3+ na rede cristalina de SnO2, substituindo átomos de Sn4+, sítio de alta simetria (D2h, C2h) apresentando um tempo de vida de emissão do 5D0 de 6ms; e o segundo referente ao Eu3+ adsorvido na superfície da partícula apresentando um tempo de vida de emissão do 5D0 de 0,3 ms. A proteção da superfície da partícula com moléculas orgânicas, beta dicetonas, originou suspensões coloidais altamente luminescentes em meio aquoso, formando um complexo com o ion Eu3+ presente na superfície da partícula, apresentando tempo de vida de 0,6 ms. Filmes finos homogêneos e transparentes foram depositados a partir das suspensões coloidais usando spin coating. Monocamadas de até 200 nm foram depositadas, observando-se o aumento linear da espessura com a concentração de material e número de depósitos. Filmes tratados a 500oC apresentam nanocristalitos de 10nm, estrutura cassiterita. Os filmes apresentam alto índice de refração e uma porosidade de 26% foi calculada. Guias...<br>The preparation of the systems doped with lanthanide ions (Eu3+ and Er3+): SnO2, HfO2, organic-inorganic hybrid system containing HfO2, SiO2- HfO2, Ta2O5 and organic-inorganic hybrid system containing Ta2O5, by using the sol gel process, have been the aim of this work. The Results of the colloidal suspension, solids (gel, xerogel and powder) and films are presented. Luminescent SnO2 colloidal suspension, with Eu3+ and Er3+ up to 2 mol%, have been prepared by redispersion of the powder (nanoparticles with modified surface) in a basic aqueous solution. Average diameter of 4 and 6nm were observed to the compounds doped and pure respectivelly, by dynamic light scattering and high resolution transmission electron microscopy. Cassiterite structure is attributed to the crystalline phase of the nanoparticles. Eu3+ ions occupied two different symmetry site. One of them corresponds to the ion in the cassiterite structure, substituting the Sn4+ ions , high symmetry site (D2h or C2h), with a 5D0 lifetime of 6ms; and the second one corresponds to the adsorbed ions on the surface, with a 5D0 lifetime of 0,3 ms. The presence of Eu3+ ions at the surface of the particles hinder their growing and also has allowed the preparation of new materials consisting of water redispersable powders coated with Eu3+-beta diketonate complex. Enhanced UV excited photoluminescence was observed in water. Homogeneous and transparent films were deposited by using the colloidal suspension by spin coating technique. Monolayers up to 200nm were prepared and a linear increase of the thickness value were observed with the concentration of the material and also the number of the layers. Films heat treated at 5000C show nanocrystals of 10nm, cassiterite structure. High ...(Complete abstract, click electronic access below)
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Livshits, Maksim Y. "Fundamental Investigation of PhotoActive Materials From Small Molecules to Materials." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1490713190973503.
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Garetto, Anthony Mr. "Electron Beam Induced Chemistry." NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-03292007-064656/.
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The purpose of this research has been to investigate the mechanisms and develop techniques for electron beam induced chemistry. Applications for electron beam chemistry include repair and fabrication of lithographic masks, integrated circuit repair and rewiring, nanofabrication of functional nanoscale tools and scanned probe microscopy tips and damage free transmission electron microscope sample preparation. The use of hydrocarbon contamination as a precursor has been investigated and complex three dimensional nanostructures have been successfully fabricated. Accelerating voltage and scan speed can be used to control the morphology of the deposits. The development and implementation of an internal precursor reservoir and introduction device that is transferable to various scanning electron microscope and focused ion beam instruments has been performed. The effects of beam and scan parameters on the deposition efficiency of carbon structures utilizing a phenanthrene precursor has been investigated. Deposition efficiency is maximized for low beam current, large scan areas exposed for short times using the experimental conditions in this work. However, the use of a focused ion beam provides a significantly higher deposition efficiency (over 45 times) than that of an electron beam.
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Rumplecker, Anja. "Host guest chemistry of mesoscopically ordered porous materials." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=984866566.
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Piña-Sandoval, Flora Marcela. "The application of microwave radiation in materials chemistry." Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/27193.
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We have developed tuned or tunable microwave cavities to be used in conjunction with an X-ray diffractometer working either in transmission mode with a capillary sample, or in reflection mode, with a flat plate. We have also developed further a microwave cavity that enables high-resolution neutron powder diffraction patterns to be taken, and tested it successfully on the High Resolution Powder Diffractometer (HRPD), at the ISIS Facility UK. One application that was planned was the elucidation of synthetic steps in the microwave-assisted formation of the zeolite ZSM-5. We also studied microwave-assisted processing of zeolites Na-Y and H-ZSM-5, accelerating the insertion of nickel, copper of molybdenum ions in the solid-state. Phase transitions in the ferroelectric materials BaTiO<sub>3</sub>, and KNbO<sub>3</sub> were studied by <i>in situ </i>diffraction to determine whether microwave irradiation can influence the transition between phases of different dielectric susceptibility, and evidence for a lower transition temperature in both cases compared to that of conventional heating. <i>In situ </i>neutron diffraction measurements have provided the first direct evidence of a differential heating under microwave irradiation of heterogeneous catalysts in the form of MoS<sub>2</sub> or Ni particles dispersed over a high surface area Al<sub>2</sub>O<sub>3</sub> support. Finally, we performed in situ X-ray diffraction on a sample of AgI held in a glass capillary to observe the transformation between the dense β phase, and the more open, fast-ion conducting α phase; this revealed a significant reduction in the transition temperature, possibly arising from a strong interaction between the microwave field and the defects or lattice modes implicated in the transition.
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Walton, Marc Sebastian. "A materials chemistry investigation of archaeological lead glazes." Thesis, University of Oxford, 2004. http://ora.ox.ac.uk/objects/uuid:eb3eb473-d434-4f45-ac78-03b6f6de3649.
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In this thesis, the fabrication technology of Roman lead glazes were examined using a number of materials science techniques: namely, electron probe microanalysis, X-ray diffraction, and inductively coupled plasma atomic emission spectroscopy. The overall aim of this work was to discern particular technological styles for a wide group of lead glazes by quantifying the chemical and microstructural features of glaze production. Using experimental replication, it was found that two basic methods of glazing could be identified chemically. When applying PbO alone to an earthenware ceramic, the resulting glaze was in equilibrium with the ceramic as indicated by flat compositional profiles obtained along the glaze cross-section. However, when applying PbO·SiO<sub>2</sub> mixtures to earthenware ceramics, gradient profiles indicative of diffusive mass transfer were obtained from the glaze cross-section. On the basis of these chemical criteria, these two methods of glazing were identified in archaeological material. It has been determined that the earliest lead glazes from Anatolia and Italy (approximately 1<sup>st</sup> century B.C.) were made using PbO·SiO<sub>2</sub> mixtures applied to calcareous clays with Fe and Cu oxides added as colourants. Later production (post 2<sup>nd</sup> century A.D.), seems to have employed PbO alone applied to non-calcareous clays with no intentionally added colourants. The Roman production of lead glazes was compared to both those of Late Antiquity (4<sup>th</sup> – 10<sup>th</sup> centuries A.D.) which continued to use PbO applied to non-calcareous clays, and to those of Byzantine and Islamic contexts (8<sup>th</sup> – 14<sup>th</sup> centuries A.D.) which seem to have used PbO·SiO<sub>2</sub> mixtures applied to both calcareous and non-calcareous clays. It is also argued that the technological features of the Byzantine and Islamic glaze production shared more in common with the contemporary Chinese lead glazing tradition (the Sancai wares of the 7<sup>th</sup> century A.D.) which also used PbO·SiO<sub>2</sub> mixtures applied to non-calcareous clays, than with the Late Antique glazing tradition.
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Zhang, Wenbin. "Soft Fullerene Materials: Click Chemistry and Supramolecular Assemblies." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1272303673.
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Sciacca, Rosalinda <1992>. "ESIX materials: insertion chemistry from a wide perspective." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10040/1/Sciacca_Rosalinda_tesi.pdf.
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This thesis aim is the synthesis, characterization and ESIX proprieties studies of Prussian Blue analogues (or Metal Hexacyanometallates, MHCMs). They are distinguished by the generic formula AxMy[B(CN)6].mH2O where, x, y, and m indicate stoichiometric coefficients, M and B are transition metals and A an alkaline metal cation. Prussian Blue (PB) analogues materials exhibit excellent physicochemical characteristics as ionic sieve. Moreover, their face-centered cubic crystal structure and the possibility to change the transition metal leads them to be an extremely versatile compound, in terms of synthesis and applications.
Properties and structures of these synthetized compounds, are investigated by using a multi-technique approach including X-ray Powder Diffraction (XRD), Scanning Electron Microscopy (SEM), Infrared Spectroscopy (IR) and electrochemical measurements. They were obtained both via electrochemical and chemical synthesis on the basis of the application field.
The main topic is related to the MHCFs release/uptake capabilities, specifically associated to structural changing.
Furthermore, their environmental sustainability and their wide field of application from sensing to batteries, allow to define them as innovative materials suitable for new analytical technologies.
Finally, the synthesis and characterization of green rust thin film is deepened, highlighting the electrochemical behavior of Akaganèite, which has a key role in the corrosion progress. Thus, understanding the electrochemical reaction involved in the corrosion processes, is useful for the diagnosis and prevention of artefacts. Also, VIMP technique allows to compare the controlled- electrodeposited green rust electrochemical behaviour with the real sample one.
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Ngabe, Barnabe. "Physical chemistry of sulphide self-heating." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123024.
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ABSTRACTA prerequisite step towards building a self-heating (SH) model for sulphide materials is the determination of physico-chemical parameters such as the specific heat capacity (Cp), and the energy of activation (Ea). The specific heat capacity of one copper and three nickel concentrates was determined over the temperature range 50 to 80oC in the presence of 6% moisture using the self-heating (SH) apparatus and confirmed by Drop Calorimetry. The Cp values from both techniques were comparable. The Cp values were similar for all concentrates increasing from 0.4 to 1.4 Jg-1K-1 as temperature increased from 50 to 80oC. From the Cp values, the enthalpy change (ΔH), the entropy change (ΔS) and the Gibbs free energy change (ΔG) for self-heating, were determined. The ΔG was negative, demonstrating that self-heating of the concentrates was spontaneous.Using the self-heating apparatus the, activation energy (Ea) was determined for the Ni-and Cu-concentrates and for pairs of sulphide minerals. The Ea ranged from 22 to 30 kJ.mol-1, implying a common reaction. Further support for a common reaction is the strong positive correlation between Ea and ln(QA/Cp) where Q (J.kg-1) is the heat of reaction causing self-heating and A the Arrhenius pre-exponential factor (s-1). Comparing to literature, the Ea values correspond to partial oxidation of hydrogen sulphide, supporting the contention that H2S may be an intermediate product in the self-heating of sulphide minerals. A positive relationship between Ea and the rest potential difference (ΔV) for the sulphide pairs and a negative relationship between Cp and ΔV were demonstrated which support a connection between self-heating and the galvanic effect.<br>RESUMÉLa réalisation d'un modèle mathématique de l'auto-échauffement des concentrés sulfurés de nickel et de cuivre et des mélanges des minerais sulfurés, enjoint à la détermination des paramètres physico-chimiques tels que les capacités de chaleur spécifiques (Cp), et les énergies d'activation (Ea). Les capacités de chaleur spécifiques d'un concentré de cuivre et de trois concentrés de nickel contenant 6% d'humidité, ont été déterminées par utilisation d'un instrument de mesure de vitesse d'auto – échauffement et validées par la calorimétrie de chute dans l'intervalle de températures allant de 50 à 80oC. Les Cp (0.4 à 1.4 Jg-1K-1) obtenues sont similaires pour tous les échantillons. A partir des valeurs des Cp, les variations de l'enthalpie (ΔH), l'entropie (ΔS) et de l'énergie libre de Gibbs (ΔG) de l'auto échauffement ont été déterminées. La valeur négative de ΔG confirme le caractère spontané de l'auto échauffement des minerais sulfurés.Les énergies d'activation (Ea) pour l'auto-échauffement des concentrés de nickel et cuivre et des paires de minerais sulfurés étaient déterminées en faisant usage de l'appareil d'auto-échauffement. Les Ea ainsi obtenues oscillent entre 22 et 30 kJ.mol-1 : Ce qui est suggestif d'une rèaction chimique commune gouvernant l'auto-échauffement de ces matériaux. Ce fait est corroboré par la forte corrélation obtenue entre Ea et ln(QA/Cp) (Q (J.kg-1) est la chaleur de la rèaction chimique responsable de l'auto-échauffement et A (s-1) la constante d'Arrhenius).Ensuite celles-ci sont similaires à celle de l'oxydation partielle du H2S. Il se pourrait, ce faisant, que H2S soit un composé intermediaire lors de l'auto–échauffement des sulfures.Enfin, la corrélation positive entre Ea et la difference de potential (ΔV) dans les paires de minerais sulfurés et celle negative entre Cp et ΔV sont une preuve qu'il existe bel et bien une connection entre l'auto-échauffement et l'effet galvanique.
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Meek, Scott Thomas. "New optical materials containing isobenzofuran." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/49742.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2009.<br>Includes bibliographical references.<br>Isobenzofuran, a member of the benzo[c]heterocycles, is an extremely reactive molecule with unusual electronic properties. In this thesis we investigate the integration of isobenzofuran subunits into conjugated optical materials. We discuss the properties of isobenzofuran, its role in organic chemistry, and the synthesis of isobenzofuran containing materials in the context of the other well known benzo[c]heterocycle, isothianaphthene. Isothianaphthene has been used in conducting polymers and organic fluorophores as a proquinoid unit, and we posit that isobenzofuran, due to its intrinsic instability, would display greater proquinoid character. To study this effect, we developed a synthetic route to integrate isobenzofuran into near-infrared donor-acceptor type fluorophores. These dyes, the IBF-NIADs, exhibit red-shifted absorption and emission over corresponding isothianaphthene containing dyes, thus highlighting the effective proquinoid nature of isobenzofuran. With the fundamentals of the IBF-NIAD dyes developed, we then expanded the series into a library of fluorophores for near-infrared fluorescence imaging application. Due to low absorption, autofluorescence, and scattering in the near-infrared region, near-infrared fluorescence imaging has the potential to provide non-invasive diagnostic techniques. In particular, our interest lay in imaging P-amyloid plaques, a hallmark pathology of Alzheimer's disease.<br>(cont.) We tailored our dye series by modifying the conjugated backbone and the electron-donating group in order to optimize their photophysical properties, minimize their aggregation in aqueous solution, and maximize their optical response on binding to P-amyloid fibrils. Through these efforts we developed several fluorophores that exhibit large bathochromic shifts on binding, with concomitant increases in fluorescence intensity and lifetime, and absorption and emission spectra that extend well into the near-infrared. With the Backskai group at MGH, we found that most of these dyes stain P-amyloid plaques in transgenic APP/PS 1 mouse brain tissue, and efforts are underway to test their in vivo imaging potential. Finally, we present our initial synthetic work in integrating isobenzofuran into donor-acceptor-donor oligomers for nonlinear optical applications.<br>by Scott Thomas Meek.<br>Ph.D.
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Huang, Wenhua. "Electrocatalysis of modified carbon materials /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487850665560626.
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Wang, Kai. "Development of Conjugated Organophosphorus Materials." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1614616540043553.
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Yang, Lusann Wren. "Data Mining Chemistry and Crystal Structure." Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11454.
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The availability of large amounts of data generated by high-throughput computing and experimentation has generated interest in the application of machine learning techniques to materials science. Machine learning of materials behavior requires the use of feature vectors that capture compositional or structural information influence a target property. We present methods for assessing the similarity of compositions, substructures, and crystal structures. Similarity measures are important for the classification and clustering of data points, allowing for the organization of data and the prediction of materials properties.<br>Engineering and Applied Sciences
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Gonçalves, Rogéria Rocha. "Preparação e caracterização de filmes óxidos contendo componentes opticamente ativos /." Araraquara : [s.n.], 2001. http://hdl.handle.net/11449/105805.
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Orientador: Sidney José Lima Ribeiro<br>Banca: Norberto Aranha<br>Banca: Leandro Tessler<br>Banca: Luis A. Carlos<br>Banca: Verónica Zéa Bermudez<br>Resumo: A preparação dos sistemas dopados com ions lantanídeos (Eu e Er): SnO2, HfO2, HfO2 disperso em matriz híbrida, SiO2-HfO2, Ta2O5, Ta2O5 disperso em matriz híbrida, através da metodologia sol gel, foi objetivo desta tese . São apresentados resultados para suspensões coloidais, sólidos (géis, xerogéis e pós) e filmes preparados por spin coating. Suspensões coloidais de SnO2 dopados com até 2% em mol de íons Eu e Er foram preparadas a partir da redispersão, em meio aquoso básico, de nanoparticulas com a superfície modificada. Diâmetro médio de 4 e 6 nm foram observados para os compostos dopados e puros respectivamente, através de espalhamento de luz e microscopia eletrônica de transmissão. Os compostos apresentam nanocristalitos, estrutura cassiterita. O íon Eu3+ ocupa dois diferentes sítios de simetria na matriz SnO2. Um referente ao ion Eu3+ na rede cristalina de SnO2, substituindo átomos de Sn4+, sítio de alta simetria (D2h, C2h) apresentando um tempo de vida de emissão do 5D0 de 6ms; e o segundo referente ao Eu3+ adsorvido na superfície da partícula apresentando um tempo de vida de emissão do 5D0 de 0,3 ms. A proteção da superfície da partícula com moléculas orgânicas, beta dicetonas, originou suspensões coloidais altamente luminescentes em meio aquoso, formando um complexo com o ion Eu3+ presente na superfície da partícula, apresentando tempo de vida de 0,6 ms. Filmes finos homogêneos e transparentes foram depositados a partir das suspensões coloidais usando spin coating. Monocamadas de até 200 nm foram depositadas, observando-se o aumento linear da espessura com a concentração de material e número de depósitos. Filmes tratados a 500oC apresentam nanocristalitos de 10nm, estrutura cassiterita. Os filmes apresentam alto índice de refração e uma porosidade de 26% foi calculada. Guias ...(Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: The preparation of the systems doped with lanthanide ions (Eu3+ and Er3+): SnO2, HfO2, organic-inorganic hybrid system containing HfO2, SiO2- HfO2, Ta2O5 and organic-inorganic hybrid system containing Ta2O5, by using the sol gel process, have been the aim of this work. The Results of the colloidal suspension, solids (gel, xerogel and powder) and films are presented. Luminescent SnO2 colloidal suspension, with Eu3+ and Er3+ up to 2 mol%, have been prepared by redispersion of the powder (nanoparticles with modified surface) in a basic aqueous solution. Average diameter of 4 and 6nm were observed to the compounds doped and pure respectivelly, by dynamic light scattering and high resolution transmission electron microscopy. Cassiterite structure is attributed to the crystalline phase of the nanoparticles. Eu3+ ions occupied two different symmetry site. One of them corresponds to the ion in the cassiterite structure, substituting the Sn4+ ions , high symmetry site (D2h or C2h), with a 5D0 lifetime of 6ms; and the second one corresponds to the adsorbed ions on the surface, with a 5D0 lifetime of 0,3 ms. The presence of Eu3+ ions at the surface of the particles hinder their growing and also has allowed the preparation of new materials consisting of water redispersable powders coated with Eu3+-beta diketonate complex. Enhanced UV excited photoluminescence was observed in water. Homogeneous and transparent films were deposited by using the colloidal suspension by spin coating technique. Monolayers up to 200nm were prepared and a linear increase of the thickness value were observed with the concentration of the material and also the number of the layers. Films heat treated at 5000C show nanocrystals of 10nm, cassiterite structure. High ...(Complete abstract, click electronic access below)<br>Doutor
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Musrock, Henry, Patrick Nshizirungu, Esther Alorkpa, and Aleksey Vasiliev. "SUPERACIDIC MATERIALS BASED ON IMMOBILIZED PHOSPHOTUNGSTIC ACID." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/asrf/2018/schedule/141.
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Phosphotungstic acid H3[PMo12O40](PTA) with the Keggin structure has become well known as a solid superacid with pKa≈-13. Such a strong acidity is caused by delocalization of the negative charge of the anion on many oxygen atoms over the surface of the Keggin structure. High acidity of PTA and its good solubility in water and other polar solvents enables its use as a highly active homogeneous catalyst. However, in spite of relatively higher reaction rate, homogeneous catalysis has various drawbacks that limit its practical application. The main drawback is the difficult and expensive removal of the used catalyst from the reaction mixture and its recycling. PTA also demonstrated good catalytic activity as a heterogeneous catalyst of various organic reactions, e.g. hydrolysis, hydration and polymerization. Wide application of a pure superacid in catalysis is limited by its low surface area and solubility in polar solvents. The objective of this work is the synthesis and study of insoluble superacidic catalysts covalently embedded into the silica matrix. The catalyst PTA/SiO2 was synthesized by the sol-gel method. Tetraethoxysilane was co-condensed with PTA in acidic media in the presence of Pluronic P123 surfactant as a pore-forming agent. The obtained gel was air-dried and calcined at 500 °C producing a mesoporous material with a significant fraction of micropores in its structure. Isotherms of adsorption/desorption of nitrogen indicated cylindrical shape of the pores with necks that is typical for materials obtained with Pluronic P123 as a template. Cs-exchanged material was prepared by mixing PTA/SiO2 with a solution of CsCl. The cation exchange on cesium decreased the total pore volume due to a much higher volume of cesium ions as compared to protons. In addition, partial pore blocking by these ions restricted access to small pores thus reducing accessible surface area. Heteropolyacids are unstable in alkaline media that makes direct solid-state titration impossible. Surface acidity of the samples was determined by reversed titration. Dry samples were dispersed in a solution of pyridine in tetrahydrofuran. After equilibration, the solid phase was filtered, and the filtrate was titrated by HCl. PTA/SiO2 has a very high adsorption capacity on pyridine, which corresponds to 15 molecules of pyridine per [PMo12O40]3- anion. This number exceeded the number of available protons. The catalysts were successfully tested in the alkylation of mesitylene by alkenes. The use of superacidic materials in catalytic reactions can significantly improve the effectiveness of the processes.
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Quast, Arthur Daniel. "Nanodiamond-Supported Composite Materials for Catalysis." Thesis, The University of Utah, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10621258.
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<p> Nanomaterials are the focus of intense research efforts in a variety of fields because of dramatic differences in properties when compared to the corresponding bulk materials. Catalysis is one material property that can become more pronounced at the nanoscale. By lowering energy requirements for chemical reactions, catalysts reduce production costs in diverse sectors of the economy, including medicine, transportation, environmental protection, oil and gas, food, and synthetic materials. Transition metals are an important class of catalysts capable of facilitating reduction and oxidation of molecular species. Since the discovery of transition metal catalysts nearly 200 years ago, certain metals were considered more active as catalysts (i.e., Pt, Pd, and Ru), while others (Au) appeared to have negligible catalytic activity as bulk materials. In recent years, gold nanoparticles (AuNPs) have become a fast-growing field of research owing to their unexpected catalytic properties not present in the bulk material. However, unsupported AuNPs are highly prone to flocculation and subsequent reduced catalytic activity. The choice of an appropriate aggregation-resistant stabilizing ligand for these nanoparticles is an important part of maintaining nanoscale catalytic properties. Additional stability is provided by anchoring AuNPs to support materials, allowing for dramatic improvements in catalyst lifetimes. This work discusses the development of novel diamond support materials for improving the stability of catalytically active AuNPs. Synthetic nanodiamond is a widely available, inexpensive, and robust material that has found applications in a wide range of commercial abrasives, lubricants, and composite materials. By exploiting the rich surface chemistry of nanodiamond, we have developed versatile catalyst support materials that offer unrivaled chemical and mechanical stability. Various nanodiamond surface modifications are readily prepared using a combination of chemical vapor deposition, photo-active polymer chemistry, and synthetic organic chemistry techniques. Control over the surface chemistry and properties of the resulting nanodiamond allow for increased stability of AuNPs via surface anchored thiol and amine moieties. The use of diamond as a support material should allow a wide variety of noble and nonprecious metal composite materials to be used as catalysts in harsh chemical environments not suitable for existing support materials.</p><p>
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King, Timothy. "Heteroatom-doped graphitic materials." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709240.
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Liddicott, Katherine Mary. "High temperature materials chemistry of doped cerium oxide ceramics." Thesis, Imperial College London, 1994. http://hdl.handle.net/10044/1/8619.
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Parker, Emma Elizabeth. "Novel complexes of molybdenum and tungsten in materials chemistry." Thesis, Bangor University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318145.
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Kirtley, Neil. "Interfacial and polymer chemistry of methacrylate based composite materials." Thesis, University of Sunderland, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302675.
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Harvey, Howard Glen. "The chemistry of new group 13 metal diphosphonate materials." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407958.
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O'Neil, David H. "Materials chemistry and physics of the transparent conducting oxides." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670028.
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Hilton, Robert Joseph. "Ferritin Diversity: Mechanistic Studies, Disease Implications, and Materials Chemistry." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/3070.
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The study of ferritin includes a rich history of discoveries and scientific progress. Initially, the composition of ferritin was determined. Soon, it was shown that ferritin is a spherical, hollow protein. Eventually, over several decades of research, the structure and some function of this interesting protein was elucidated. However, the ferritin field was not completely satisfied. Today, for example, researchers are interested in refining the details of ferritin function, in discovering the role of ferritin in a variety of diseases, and in using ferritin for materials chemistry applications. The work presented in this dissertation highlights the progress that we have made in each of these three areas: 1) Mechanistic studies: The buffer used during horse spleen ferritin iron loading significantly influences the mineralization process and the quantity of iron deposited in ferritin. The ferrihydrite core of ferritin is crystalline and ordered when iron is loaded into ferritin in the presence of imidazole buffer. On the other hand, when iron is loaded into ferritin in the presence of MOPS buffer, the ferrihydrite core is less crystalline and less ordered, and a smaller amount of total iron is loaded in ferritin. We also show that iron can be released from the ferritin core in a non-reductive manner. The rate of Fe3+ release from horse spleen ferritin was measured using the Fe3+-specific chelator desferoxamine. We show that iron release occurs by three kinetic events. 2) Disease studies: In order to better understand iron disruption during disease states, we performed in vitro assays that mimicked chronic kidney disease. We tested the hypothesis that elevated levels of serum phosphate interrupted normal iron binding by transferrin and ferritin. Results show that phosphate competes for iron, forming an iron(III)-phosphate complex that is inaccessible to either transferrin or ferritin. Ferritin samples separated from the iron(III)-phosphate complex shows that as the phosphate concentration increases, iron loading into ferritin decreases. 3) Materials chemistry studies: Anion sequestration during ferritin core reduction was studied. When the core of horse spleen ferritin is fully reduced using formamidine sulfinic acid, a variety of anions, including halides and oxoanions, cross the protein shell and enter the ferritin interior. Efforts have been made to use ferritin to control the concentration of anions for reactions. In addition, the native ferrihydrite mineral core of ferritin is a semi-conductor capable of catalyzing oxidation/reduction reactions. Light can photo-reduce AuCl4- to form gold nanoparticles (AuNPs) with ferritin as a photocatalyst. The mechanism of AuNP formation using ferritin as a photocatalyst was examined. From this work, we propose that the ferrihydrite core of ferritin photo-reduces; the mineral core dissolves into a soluble iron(II) mineral. The iron(II) then re-oxidizes, and a new mineral forms that appears to be the new photocatalyst, as the lag phase is significantly decreased with this new mineral form of ferritin.
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Botos, Ákos. "Inorganic materials in hollow carbon nanostructures." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/31915/.
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The interactions of metal-containing molecules and nanoparticles (NPs) with the interior of hollow graphitic carbon nanostructures (CNs) were investigated and their chemical transformations in the nanoscale channels of CNs appraised. The gas phase insertion of Group VI metal hexacarbonyl complexes (M(CO)6, M=Cr, Mo, W) into CNs was successfully developed and optimised to provide good filling rates as confirmed by transition electron microscopy (TEM). Infrared (IR) and Raman spectroscopy demonstrated that Group VI M(CO)6 complexes with greater polarisability exhibit stronger van der Waals interactions with the interior of single walled carbon nanotubes (SWNTs). The synthesis of metal based NPs inside graphitised carbon nanofibers (GNFs) by the in situ transformation of the encapsulated M(CO)6 precursor molecules was successfully achieved and it was demonstrated that GNFs can act as a source of oxygen in these reactions. The nanotube filling methodology was applied for the multi-step synthesis of new inorganic materials inside CNs by the controlled reactions of M(CO)6, I2 and H2S. This approach yielded unusual van der Waals hybrid materials such as “tube inside a tube” and other hybrid structures of MoS2 and GNFs. In SWNTs, with significantly narrower diameters than GNFs or multi-walled carbon nanotubes (MWNTs), metal complexes form unique 1D arrays of octahedral [M6I14]2- clusters with the nanotube acting as a nanocontainer and a poly-cation balancing the charge of the guest-clusters. The iodides of Mo and W were effectively converted into extremely thin MS2 nanoribbons (NRs) within SWNTs, providing a new more efficient route to the hybrid inorganic nanostructures. In MWNTs, the [Mo6Ii8Ia2Ia a4/2] clusters are packed in a hexagonal pattern to optimise filling of the void, and when reacted with H2S they provide a range of multi-layered MS2NRs with their widths controlled by the internal diameter of the host nanotube.
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Sudhakaran, Pillai S. "Luminescent materials based on Lanthanide ions." Thesis, Kingston University, 2010. http://eprints.kingston.ac.uk/20413/.
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The inclusion of lanthanide (III) (Ln[sup]3+) ions into polymers by “covalent” bonding has applications. Heteroleptic hydrotris(pyrazolyl)borate crotonate and cinnamate complexes were synthesised for reasons that, firstly, knowledge of the polymerisable double bond was helpful in establishing the conditions of any copolymerisation reaction; secondly, the chosen ligands are very good at receiving energy in the UV region; and thirdly, lanthanide complexes might undergo changes in properties, on moving between adjacent lanthanide ions, allowing potentially convenient isolations of pure materials at the monomer production stage, or even at the polymerisation stage. For both complexes, two classes of target complex were identified: the mononuclear (Er-Lu) and dinuclear (La-Ho). Mononuclear forms were identified by MS, [sup]1H NMR and elemental analysis and dinuclear forms were characterised by X-ray crystallography. For heteroleptic hydrotris(pyrazolyl)borate crotonate and cinnamate complexes, the ligands act as antennae for receiving and then transferring energy to metal ions and these complexes were studied in several homogeneous and heterogeneous copolymers as well as in rigid PMMA or polystyrene matrices. Luminescence decay of these complexes depends on the distance between the metal and C-H oscillators so the cinnamate complexes showed better luminescence life-times compared to crotonate complexes. The copolymer system helped to reduce the concentration quenching compared to corresponding metal complex / polymer blend systems. The thermal stabilities of the complex monomers were increased by incorporating them into polymer chains. Europium crotonate and cinnamate complexes in the poly(p-phenylenevinylene) (PPV) precursor blends showed the characteristic emission of europium, and the emission from PPV was quenched by increasing the europium content in the PPV precursor blends.
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Statz, Eric R. (Eric Robert). "Phonon polariton interaction with patterned materials." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43770.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2008.<br>Vita.<br>Includes bibliographical references (p. 139-144).<br>The generation, propagation and detection of THz phonon polaritons are studied through both femtosecond pump-probe techniques, and Finite Difference Time Domain (FDTD) simulations in this thesis. The theory surrounding the driving, propagation and detection of these modes is treated in a consistent notational system for both analytical solutions and approximate simulated responses. FDTD simulations in one, two and three dimensions are designed to best mimic lab experimental parameters, with various approximations of both THz pumping and probing developed. Various improvements on the FDTD method with the goal of more rapid simulations and more accurately described simulations of lab experiments from generation to detection are considered and developed. Experiments on phonon-polaritons interacting with periodicity and confinement in one, two, and three dimensions are all considered, and methods of data processing developed. By comparing FDTD simulation results to experimental results, the full three dimensional fields within these crystals can be investigated, and in many cases fully defined. The methods demonstrated open up new possibilities for THz spectroscopy in waveguides, microfluidics, and related platforms that include THz generation, propagation, interaction with the sample material, and detection in a compact, integrated structure. The methods also enable the proper description of large-amplitude THz generation and applications in nonlinear THz spectroscopy. Finally, linear and nonlinear THz signal processing applications my exploit the experimental and modeling methods described in this thesis.<br>by Eric R. Statz.<br>Ph.D.
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Van, Schalkwyk Welmarie. "Self-assembly of amphiphilic discotic materials." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/79799.
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Thesis (MSc)--Stellenbosch University, 2013.<br>ENGLISH ABSTRACT: The creation of nanometer-scale (nanoscale) materials has fascinated and inspired the scientific community for more than a quarter of a century because of the wide range of applications of these materials, e.g. applications in drug delivery, medicine, tissue engineering, memory storage, display and audio devices, semiconductors, etc.
π-Conjugated dendrimers have a proposed flat packing arrangement. An alternating phenyl isoxazole dendrimer system was developed to investigate this phenomenon. The synthesis of this dendritic system was attempted by divergent and convergent approaches. Preparation of the second generation failed because some functional groups inhibited the monomers to react to the first generation.
Other examples of nano materials that have attracted a vast amount of interest are the so-called discotic amphiphiles. Discotic amphiphilic molecules have the potential to self-assemble into helical architectures.
Discotic systems bearing chiral polar side chains (one and three respectively) were developed. Their self-assembly was investigated in variable concentration and variable solvent composition experiments. These systems did show signs of aggregation in UV-vis and CD spectroscopy experiments. Thread-like helical structures were observed with transmission electron microscopy.<br>AFRIKAANSE OPSOMMING: Nanometer-skaal materiale inspireer en fassineer wetenskaplikes al vir meer as 25 jaar as gevolg van hulle wye verskeidenheid toepassings bv.: die vervoer van geneesmiddels, weefsel ontwerp, geheue stoorspasie, digitale skerms, klank toerusting, geleiers, ens.
π-Gekonjugeerde dendrimere het 'n plat drie dimmensionele rangskikking. 'n Afwisselende feniel isoxazole dendrimer stelsel was ontwikkel om hierdie verskynsel te ondersoek. Die sintese van hierdie dendritiese stelsel is aangepak deur divergerende en konvergerende benaderings. Sintese van die tweede generasie het misluk omdat sommige funksionele groepe die monomere geïnhibeer het om te reageer met die eerste generasie.
Ander interessante voorbeelde van nano materiale, is die sogenaamde skyfvormige amphiphiles. Skyfvormige amphiphiles het die potensiaal om spontaan te versamel in heliese strukture.
Skyfvormige molekules met chirale polêre sykettings (een en drie onderskeidelik) is ontwikkel. Hulle potensiaal om spontaan te versamel is ondersoek met wisselende konsentrasie en wisselende oplosmiddel samestelling eksperimente. Hierdie stelsels het tekens van versameling gewys in UV-vis en CD-spektroskopiese eksperimente. Staaf-vormige heliese strukture is waargeneem met transmissie-elektronmikroskopie.
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Li, Shanghua. "Fabrication of Nanostructured Materials for Energy Applications." Doctoral thesis, Kista : Division of Functional Materials, Department of Microelectronics and Applied Physics, School of Information and Communication Technology, Royal Institute o Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4807.
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Chisham, Jason E. (Jason Edward). "Sol-gel materials for integrated optics." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23992.
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The sol-gel process is a low temperature solution route to amorphous and crystalline materials. Organic modification of the precursors allows the formation of organic-inorganic composite materials. We use the sol-gel process to produce an organically-modified ceramic for integrated optical applications. Photosensitive organic components allow the fabrication of passive integrated optical devices by photolithography. We demonstrate the fabrication and characterization of channel waveguides, waveguide devices and gratings in this material. Active devices based on the emission of erbium at 1.55 $ mu$m are under much investigation because of their potential use in telecommunications. Luminescence quenching is a major problem as an Er$ sp{3+}$ ion in its excited state transfers its energy to a nearby vibrational mode of its environment and decays non-radiatively to the ground state. Encapsulation of the ion into a coordination sphere to shield the ion from its surroundings may lead to reduced quenching. We synthesize several erbium tetrakis $ beta$-diketone complexes and dope them into different solvent environments and sol-gel hosts to probe guest-host interactions in the excited state.
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Chen, Rui. "HIGH PERFORMANCE SOLUTION-PROCESSED PEROVSKITE PHOTOVOLTAICS BY NOVEL MATERIALS." University of Akron / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=akron1617818409646272.
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Muizzi, Casanas Dayana Andreina. "Light Activated Nitric Oxide Releasing Materials." Bowling Green State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1435581276.
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Jenkins, Neil Travis 1973. "Chemistry of airborne particles from metallurgical processing." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/17033.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2003.<br>Vita.<br>Includes bibliographical references.<br>Airborne particles fall into one of three size ranges. The nucleation range consists of nanoparticles created from vapor atom collisions. The decisive parameter for particle size and composition is the supercooling of the vapor. The accumulation range, which comprises particles less than 2 micrometers, consists of particles formed from the collision of smaller primary particles from the nucleation range. The composition of agglomerates and coalesced particles is the same as the bulk vapor composition. Coarse particles, the composition of which is determined by a liquid precursor, are greater than 1 micrometer and solidify from droplets whose sizes are controlled by surface, viscous, and inertial forces. The relationship between size and composition of airborne particles could be seen in welding fume, a typical metallurgical aerosol. This analysis was performed with a cascade impactor and energy dispersive spectrometry with both scanning electron microscopy (SEM-EDS) and scanning transmission electron microscopy (STEM-EDS). Other methods for properly characterizing particles were discussed. In the analysis, less than 10% of the mass of fume particles for various types of gas metal arc welding (GMAW) were coarse, while one-third of flux cored arc welding (FCAW) fume particles were coarse. Coarse particles had a composition closer to that of the welding electrode than did fine particles. Primary particles were not homogeneous. Particles larger than the mean free path of the carrier gas had the same composition as that of the vapor, but for particles 20 to 60 nanometers, smaller particles were more enriched in volatile metals than larger particles were. This was explained by the cooling path along the bubble point line of a binary phase diagram.<br>(cont.) Particles were not necessarily homogenous internally. Because nanoparticles homogenize quickly, they may form in a metastable state, but will not remain in that state. In this analysis, the presence of multiple stable immiscible phases explains this internal heterogeneity. The knowledge contained herein is important for industries that depend on the properties of nanoparticles, and for manufacturing, where industrial hygiene is important because of respirable particle by-products, such as high-energy-density metallurgical processing.<br>by Neil Travis Jenkins.<br>Ph.D.
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Frank, Robert A. "Physical chemistry of carbothermic reduction of alumina." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15150.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1985.<br>MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE<br>Vita.<br>Bibliography: leaves 177-180.<br>by Robert A. Frank.<br>M.S.
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Twu, Jen. "Synthetic, mechanistic and structural chemistry of zeolitic and intercalation materials /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487683756124307.
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Sui, Yongqiang. "Toward polar 1,4-diphenylbutadiene materials." Diss., Columbia, Mo. : University of Missouri-Columbia, 2004. http://hdl.handle.net/10355/4099.
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Thesis (M.S.)--University of Missouri-Columbia, 2004.<br>The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (June 30, 2006). Includes bibliographical references.
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Tavener, P. "Electron spectroscopy of electrode materials." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370304.
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Mellor, Helen. "Electroabsorption spectroscopy of conjugated materials." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287725.
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AricoÌ, Fabio. "New architectures for molecular materials." Thesis, University of Reading, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252257.
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Jones, Christopher Lloyd. "Some novel oligothiophene-based materials." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343689.
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Chirico, Pietro. "Synthesis of nanocrystalline nitride materials." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/193141/.
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Evans, Gary. "Nanometric oxides for functional materials." Thesis, University of Liverpool, 2010. http://livrepository.liverpool.ac.uk/1434/.
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This thesis describes the synthesis and application of complex metal oxide nanoparticles. The work is focussed on three core areas; the synthesis of CoFe2O4 nanoparticles and their application as CO oxidation catalysts, the controlled assembly of functionalised CoFe2O4 and BaTiO3 nanoparticles and the preparation and characterisation of magnetoelectric composites from chemically-bonded nanoparticle assemblies. Chapter 1 gives an introduction to the history of nanotechnology, recent developments in the synthesis of nanoparticles and other areas key to the work described herein. In Chapter 2 details the synthetic and analytical techniques employed. Chapter 3 describes the synthesis and characterisation of CoFe2O4 nanoparticles, and their application as catalysts in the CO oxidation reaction. Nanoparticles were prepared with a range of controlled sizes and were found to be active CO oxidation catalysts. Analysis of their size-dependent activity and stability is performed. Chapter 4 describes the assembly of CoFe2O4 and BaTiO3 nanoparticles by direct functionalisation of the nanoparticle surfaces using complementary organic functional molecules. Characterisation of the functionalised nanoparticles and assemblies is performed, and the extensibility of the developed functionalisation and assembly protocol is tested using particles with different sizes and morphologies. In Chapter 5 the assembled nanoparticles discussed in Chapter 4 are processed into dense ceramics with a view to preparing magnetoelectric composites. The magnetoelectric properties are tested, and optimisation of the ceramics is performed by modification of the starting nanoparticle sizes, composite composition and processing conditions. The composites are tested against control samples prepared by traditional grinding and firing, and characterisation of the ceramics using XRD and electron microscopy provides and insight as to why their magnetoelectric properties differ to those prepared by the traditional technique. The work contained in this thesis has been published in the following papers: - G. Evans, I. V. Kozhevnikov, E. F. Kozhevnikova, J. B. Claridge, R. Vaidhyanathan, C. Dickinson, C. D. Wood, A. I. Cooper, M. J. Rosseinsky, “Particle-size Activity Relationship for CoFe2O4 Nanoparticle CO Oxidation Catalysts,” J. Mater. Chem. 2008, 18, 5518. G. Evans, G. V. Duong, M. J. Ingleson, Z. Xu, J. T. A. Jones, Y. Z. Khimyak, J. B. Claridge, M. J. Rosseinsky, “Chemical Bonding Assembly of Multifunctional Oxide Nanocomposites,” Adv. Funct. Mater. 2010, 20, 231.
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Ikumapayi, Fatai Kolawole. "Flotation chemistry of complex sulphide ores : recycling of process water and flotation selectivity." Licentiate thesis, Luleå tekniska universitet, Industriell miljö- och processteknik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26634.
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Recycling of flotation effluents through the ore processing plant is one of the ways of reducing both plant-operating costs and industrial impact onto the local ecosystem. Such waters named acid mine drainage (AMD), if discharged from sulphide flotation are gypsum (CaSO4.H2O) saturated and have a high salinity (on the order of 1000 ppm). As minor species, they commonly contain reduced sulphur compounds (RSC) (sulfoxyanions with sulphur in the oxidation state below (VI) such as SO32-, S2O32-, S2O52-, and S4O62-), cations of ferrous and non-ferrous metals, frothing molecules, residual chemical reagents and products of their degradation. Tailing ponds also host communities of chemolithotrophic and heterotrophic microorganisms which play an important role in dictating their aqueous and solid phase chemical speciation. Consequently, the key step towards developing scientific approaches of recycling of the tailing waters is elucidation of how, in what extent, and why the tailing water components, taken singly or jointly influence flotation of sulphides. In this work, the influence of main process water components of calcium and sulphate on chalcopyrite, galena, sphalerite and pyrite flotation has been investigated through Hallimond flotation, zeta-potential and diffuse reflectance FTIR spectroscopy measurements using pure mineral samples as well as bench scale flotation tests using complex sulphide ore. The significance of process water species in flotation has been assessed using deionised water, process water and simulated water containing calcium and sulphate ions in experiments. In addition, the effect of temperature in bench scale flotation tests has also been examined. Hallimond flotation indicated depression of chalcopyrite, galena and sphalerite and activation of pyrite in the presence of calcium and sulphate ions with potassium amyl xanthate as collector. Calcium ions have significant influence on zeta-potential characteristics and xanthate adsorption behaviour of chalcopyrite, galena, sphalerite and pyrite compared to sulphate ions. FTIR studies revealed the presence of surface oxidised sulfoxy species and surface iron and calcium carbonates on chalcopyrite in the presence of process water and water containing calcium ions, surface oxidised sulfoxy and carbonate species on galena in the presence of deionised water, process water and water containing calcium and sulphate ions, hydrated surface oxidised species and surface iron and calcium carbonates on pyrite in the presence of process water and water containing calcium ions all at pH 10.5 in which the surface species influenced xanthate adsorption. The presence of surface oxidised sulfoxy and carbonate species on sphalerite were also revealed at pH 11.5 in the presence of deionised water, process water and water containing calcium and sulphate ions in which surface species does not influence xanthate adsorption. Bench scale flotation using two different complex sulphide ores showed that chalcopyrite recovery is better in process water than tap water and general depression of chalcopyrite at temperatures lower than 22oC in either tap water or process water, activation of chalcopyrite at all temperatures in process water and depression of chalcopyrite when tap water containing calcium and sulphate ions was used at 22oC. It also showed that galena recovery is better in tap water than process water and depression of galena at temperatures lower than 22oC in either tap water or process water. It also showed that sphalerite recovery is better in process water than in tap water better recovery of sphalerite at temperatures lower than 22oC in either tap water or process water.<br>Godkänd; 2010; 20101114 (fatiku); LICENTIATSEMINARIUM Ämnesområde: Mineralteknik/Mineral Processing Examinator: Professor Kota Hanumantha Rao, Luleå tekniska universitet Diskutant: PhD Jaakko Leppinen, Outotec, Non-Ferrous Solutions, Espoo, Finland Tid: Fredag den 10 december 2010 kl 10.00 Plats: F531 Bergrum, Luleå tekniska universitet