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Iotov, Mitko. "Ionomers azobenzene crystallines liquides photoactive." Mémoire, [S.l. : s.n.], 2006. http://savoirs.usherbrooke.ca/handle/11143/4688.
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Simpson, Robert Luke. "Metamorphism, melting and extension at the top of the high Himalayan slab, Mount Everest region, Nepal and Tibet." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249333.
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Wang, Kai. "Involvement of O-glcnacylation in lens development and cataract formation." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2010r/wang.pdf.
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Lau, Richard Yiu-Ting. "Surface segregation of amorphous, semi-crystalline and liquid crystalline polymers /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?CENG%202006%20LAUR.
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Nie, Lei. "Liquid crystalline thermosets." Thesis, University of Sheffield, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.574560.
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Liquid crystalline thennosets (Lt.Ts) are a special class of materials which generated significant interest since they demonstrated the combination of the anisotropic physical properties of the mesophase and the specific properties of thennosets. Among them, the water barrier property of LeTs makes them very promismg materials for the potential applications in electronics and coatings. Liquid crystalline monomer, 4, 4'-diglycidyloxy-a-methylstilbene (DOMS), was synthesized and cured with different crosslinking agents, such as sulphanilamide, diaminodiphenylsulfone, diaminodiphenylmethane, and 2,4-Diaminotoluene. LeTs with different liquid crystalline structures were produced and their structural, dynamic mechanical and permeability properties are characterised. The conventional epoxy monomer, diglycidyl ether of bisphenol-A (BADGE) is also involved in our study and resins formed by BADGE and curing agents are used as comparisons to the DOMS LeT systems. Polarized optical microscopic tests were used to form time-temperature-transition (TTT) diagrams for different systems, which provide important information about the curing process of Lf.Ts. Relationships between curing conditions, structure and properties are created by TTT diagrams and microscopic observations. Differential scanning calorimetry and wide angle X-ray scattering tests demonstrated the typical smectic features of LeTs systems. In the dynamic vapour sorption tests, the extraordinary water barrier property of smectic LeT is revealed. The water permeability of LeT was reduced by 74.6% at 65 'C and by 63.7% at 85'C in comparison with the conventional thermoset. Smectic Le structure was proven useful in reducing the water permeation in epoxy thennosets. Dynamic mechanical analysis combined with computer modelling was employed to investigate the correlation between water permeation and inner structure of materials to clarify the mechanism of moisture diffusion and sorption in LCTs. The information and results obtained in this work would be of great importance for the potential industrial applications of LeTs. - i -
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FernaÌndez, Iglesias Eva. "Liquid-crystalline phenanthrolines." Thesis, University of Exeter, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269721.
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Acosta-Sampson, Ligia I. "In vitro interactions of the small heat shock protein chaperone human [alpha]B-crystallin with its physiological substrates in the lens [gamma]-crystallins." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61787.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
In title on title-page "[alpha]" and "[gamma]" appear as lower case Greek letters. Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 160-175).
The passive chaperone a-crystallin, a small heat shock protein, is one of the ubiquitous crystallins in vertebrate lenses, along with the [beta][gamma]-crystallins. It is composed of two subunits (~ 20 kDa) aA- and [alpha]B-crystallin (aA- and [alpha]B-Crys), which form a hetero-oligomeric, polydisperse complex of ~ 800 kDa in the lens. Aggregates isolated from mature-onset cataracts, the major cause of sight loss worldwide, contain damaged and misfolded forms of [beta][gamma]-crystallins, as well as a-crystallins. I have studied the chaperone function of human [alpha]B-crystallin interacting with its physiological human [gamma]-crystallin substrates. Human [gamma]D-crystallin ([gamma]D-Crys) and [gamma]C-crystallin ([gamma]C-Crys) are st[alpha]Ble and long-lived mammalian [gamma]-crystallins localized in the lens nucleus. Human [gamma]S-crystallin ([gamma]S-Crys) is [alpha]Bundant in the lens outer cortex. All three [gamma]-crystallins can refold in vitro to their native state after unfolding in high concentrations of guanidine hydrochloride (GdnHCl). However, in buffer or very low denaturant concentrations (< 1 M GdnHCl) aggregation of refolding [gamma]-crystallin intermediates competes with productive refolding. Diluting unfolded [gamma]C-, [gamma]D-, or [gamma]S-Crys to low GdnHCl concentrations (at 100 [mu]g/ml, 37°C) resulted in the protein population partitioning between productive refolding and aggregation pathways. [gamma]D-, [gamma]C- or [gamma]S-Crys protein was allowed to refold and aggregate in the presence of [alpha]B-Crys homo-oligomers at different mass-based ratios of [gamma]-Crys to [alpha]B-Crys. [gamma]D- and [gamma]C-Crys aggregation was suppressed to similar levels, whereas [gamma]S-Crys aggregation was not suppressed as strongly in assays measuring solution turbidity at 350 nm. SEC chromatograms of the products of suppression reactions showed the presence of a high molecular weight chaperone-substrate complex. This complex was still present 4 days after the suppression reaction was initiated. Experiments were performed with the [alpha]B-Crys chaperone added 2, 6, or 10 s, after dilution of unfolded [gamma]D-Crys out of high concentrations of denaturant. The results from these experiments showed that the partially folded, aggregation-prone species that is recognized by [alpha]B-Crys chaperone is populated within the first 10 s after refolding and aggregation were initiated. This time period coincided with the refolding of the C-terminal domain of [gamma]D-Crys as determined from kinetic refolding experiments in vitro. Human [gamma]D-Crys contains four Trp residues with one residue located in each quadrant of the protein. Intrinsic buried Trp fluorescence is quenched in the native state relative to the unfolded state of the protein due to intra-domain partial resonance energy transfer from the highly fluorescent Trp donors (W42 and W130) to the highly quenched acceptor Trps (W68 and W156). The efficient quenching of Trp68 and Trp156 depends on an unusual conformation of the Trp ring with respect to its backbone amide, as well as the presence of two tightly bound H2O molecules with oppositely oriented dipoles. Thus, intrinsic Trp fluorescence is a sensitive reporter of the protein conformation. Using a no-Trp mutant of [alpha]B-Crys (W9F/W60F), the conformation of the bound [gamma]D-Crys substrate in [gamma]D -- [alpha]B complexes was determined from intrinsic Trp fluorescence emission. The emission spectra for the substrate did not coincide with a native or fully unfolded conformation of the [gamma]D-Crys controls. To further characterize the conformation of each domain of [gamma]D-Crys in the substrate-chaperone complex, double-Trp [gamma]D-Crys mutants, which conserved the Trp pair in the N-terminal (W130F/W156F) or the C-terminal (W42F/W68F) domain, while the counterpart pair was changed to Phe, were used as substrates in aggregation suppression reactions. The fluorescence emission spectra for the double-Trp mutants in complex with Trp-less [alpha]B-Crys were similar and they did not coincide with the spectra for their respective native or unfolded double-Trp [gamma]D-Crys controls. These results indicated that the bound substrate remained in a partially folded state with neither domain native-like. Triple-Trp [gamma]D-mutants that conserved the highly fluorescent Trp residue in the N-terminal or C-terminal domains were also used as substrates in suppression of aggregation reactions with Trp-less [alpha]B-Crys chaperone. The fluorescence emission spectra of triple-Trp substrates in the substrate-chaperone complex indicated that these residues were not solvent exposed. These results suggest that Trp neighboring regions could be interacting directly with the [alpha]B-Crys chaperone. To further elucidate the specific region in the [gamma]-crystallins that interacts with [alpha]B-Crys in suppression assays, experiments were performed using single-domain constructs of [gamma]D-Crys. The isolated N-terminal ([gamma]D-Ntd) and C-terminal domains ([gamma]D-Ctd) of [gamma]D-Crys, expressed in E. coli, can refold to a native state upon dilution out of denaturant to low concentrations of GdnHCl. The C-terminal domain aggregated upon refolding out of high concentrations of denaturant, while the N-terminal did not under the same assay conditions. However, when [gamma]D-Ctd and [gamma]D-Ntd were unfolded and refolded together, [gamma]D-Ctd recruited [gamma]D-Ntd into the aggregate. [alpha]B-Crys suppressed the aggregation of the [gamma]D-Ctd and formed [gamma]D-Ctd -- [alpha]B complexes. Using W9F/W60F [alpha]B-Crys, I have determined, through the fluorescence emission of [gamma]D-Ctd tryptophans, that the [gamma]D-Ctd in the [gamma]D-Ctd --[alpha]B complexes was partially folded. Inhibition experiments in which the [gamma]D-Ntd and [gamma]D-Ctd isolated domains were refolded sequentially or simultaneously showed that [alpha]B-Crys preferentially recognized [gamma]D-Ctd. These in vitro results provide a model for how a-crystallin interacts with aggregation-prone substrates in vivo wherein an aggregation-prone region in the C-terminal domain of [gamma]D-Crys is exposed in the aggregation-prone species and this region is recognized by [alpha]B-Crys. These results also provide support for protein unfolding/protein aggregation models for cataract, with a-crystallin suppressing aggregation of damaged or unfolded proteins through early adulthood, but becoming saturated with advancing age.
by Ligia Acosta-Sampson.
Ph.D.
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Zhou, Bo. "Synthesis and characterization of crystalline assembly of poly Nisopropylacry-lamide)-co-acrylic acid nanoparticles." Thesis, University of North Texas, 2004. https://digital.library.unt.edu/ark:/67531/metadc4671/.
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In this study, crystalline poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAm-co-AAc) nanoparticle network in organic solvents was obtained by self assembling precursor particles in acetone/epichlorohydrin mixture at room temperature followed by inter-sphere crosslinking at ~98 °C. The crystals thus formed can endure solvent exchanges or large distortions under a temporary compressing force with the reoccurrence of crystalline structures. In acetone, the crystals were stable, independent of temperature, while in water crystals could change their colors upon heating or changing pH values. By passing a focused white light beam through the crystals, different colors were displayed at different observation angles, indicating typical Bragg diffraction. Shear moduli of the gel nanoparticle crystals were measured in the linear stress-yield ranges for the same gel crystals in both acetone and water. Syntheses of particles of different sizes and the relationship between particle size and the color of the gel nanoparticle networks at a constant solid content were also presented. Temperature- and pH- sensitive crystalline PNIPAm-co-AAc hydrogel was prepared using osmosis crosslinking method. Not only the typical Bragg diffraction phenomenon was observed for the hydrogel but also apparent temperature- and pH- sensitive properties were performed. The phase behavior of PNIPAm nanoparticles dispersed in water was also investigated using a thermodynamic perturbation theory combined with lightscattering and spectrometer measurements. It was shown how the volume transition of PNIPAM particles affected the interaction potential and determined a novel phase diagram that had not been observed in conventional colloids. Because both particle size and attractive potential depended on temperature, PNIPAM aqueous dispersion exhibited phase transitions at a fixed particle number density by either increasing or decreasing temperature. The phase transition of PNIPAm-co-AAc colloids was also studied. The results from the comparison between pure PNIPAm and charged PNIPAm colloids showed that the introducing of carboxyl (-COOH) group not only contributed to the synthesis of three-dimensional nanoparticle network but also effectively increased the crystallization temperature and concentration range. The phase transitions at both low and high temperatures were observed from the turbidity change by using UV-Vis spectrometer. Centrifugal vibration method was used to make crystalline PNIPAm-co-AAc dispersion at high concentration (8%). The turbidity test proved the formation of iridescent pattern.
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Di, Lollo Antonio B. "Thermal and surface properties of crystalline and non-crystalline legume seed proteins." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59973.
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This work was devoted to the study of (a) the physico-chemical, functional, and structural properties of bean (Phaseolus sp.) protein isolates in relation to their microstructures, and (b) the effects of protein carbohydrate interactions on physico-chemical, functional, and structural properties. The contents of protein, and both total and individual sugars of alkali extracted (amorphous) and citric acid extracted (bipyramidal and spheroidal) proteins from Phaseolus vulgaris (white kidney and navy) and Phaseolus lutanus (baby lima and large lima) beans were determined. The proteins were subjected to differential scanning calorimetry, and measurements of surface tension (air-water interface), surface hydrophobicity, and foam expansion. Structural analysis of the proteins were performed using Fourier transform infrared (FT-IR) spectroscopy. Enzymatic and chemical deglycosylation was performed on a white kidney bean protein isolate.Glucose and mannose were the major sugars found in the isolates. Bipyramidal and spheroidal microstructures with higher protein contents generally had greater mannose content and lower glucose content. Differences in enthalpy of denaturation $( Delta$H), surface tension decay curves, surface hydrophobicities, and foam expansions were observed with isolates of different microstructures. Corresponding differences in molecular structure were not, however, detected by FT-IR spectroscopy. Using statistical analysis, a relationship between foam expansion and the $ Delta$H, solubility, surface hydrophobicity and surface tension of the isolates was obtained. Preliminary results suggest that the removal of carbohydrate influenced the physico-chemical properties of the protein.
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Hanna, Simon. "Structure and phase transitions of some crystalline and liquid crystalline aromatic polyesters." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277892.
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Chaves, Jose Mauro. "Structural and functional properties of human [alpha]A-crystallin." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2008d/chaves.pdf.
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Yue, Wenbo. "Mesoporous crystalline metal oxides." Thesis, St Andrews, 2009. http://hdl.handle.net/10023/830.
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Almasri, Moayad. "Liquid crystalline conducting polymers." Thesis, Kingston University, 2008. http://eprints.kingston.ac.uk/20393/.
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Side chain liquid crystal polypyrroles have been synthesised and investigated in order to study their liquid crystallinity and its possible effect on their electronic conductivity. The synthesis ofN-substituted dithienylpyrrole was studied using a number of methods. Firstly, there was the synthesis of a side chain which consisted of a mesogenic group and nine units of methylene as a spacer. This synthesis was followed by the preparation of the N-substituted monomer, its polymerisation and the characterisation of both the low molecular weight compounds and the polymer. The next stage was the hydrolysis of the cyanobiphenyl (the mesogenic group) and esterification with a chiral alcohol. The purpose was to synthesise N-substituted polypyrrole with a chiral liquid crystalline moiety in order to produce new liquid crystalline conductive polymers which could exhibit a chiral smectic Cmesophase. A larger monomer (dithienylpyrrole) was synthesised. The substitution of the monomer was carried out using several methods, and the production of the N-substituted monomer was attempted using the Gabriel Synthesis and alternative Suzuki Coupling methods. The polymers were studied electrochemically, and the conductivity of the chemically polymerised compounds was measured (2.8 x 10-8 S cm-1 for the nitrile polymer). The effect of heat treatment on a film of the electrochemically polymerised product was studied, and the energy gap before and after the annealing was measured (2.7 to 2.6 eV for the nitrile polymer and the acid polyer). The liquid crystalline properties were studied 'using differential scanning calorimetry and polarised hot-stage optical microscopy. The acid intermediate (product 3) showed two liquid crystal mesophases. Nematic and smectic C mesophases were observed to be stable over a wide range of temperature (144.8 to 241.4 [degrees]C). The nitrile polymer showed a highly organised phase which was probably a smectic B or crystal. B phase. The nitrile polymer and the acid polymer were studied electrochemically showing that doping and dedoping potentials for the acid polymer were higher than those of the nitrile polymer, and the energy gap of the acid polymer was lower. The energy gap of the nitrile polymer was higher than that of polymer with shorter spacer (6 units of methylene), and that was consistent with the results obtained from the conductivity measurement, as the longer spacer polymer is less conductive (higher energy gap and lower conductivity). Annealing the polymers decreases the energy gap due to self-organisation of the liquid crystal phase .: Modelling the monomer using Quantum Cache indicated molecular dimensions (the length of the nitrile monomer with an LC group attached is 27.8 AO) consistent with the repeat distances indicated by X-ray diffractometry (27.6 AO for the nitrile polymer). The result was proposed that there was inter-layer of the smectic LC phase indicated by hot¬stage polarised optical microscopy.
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Svensson, Erik. "Crystalline properties of starch." Lund : Lund University, 1996. http://books.google.com/books?id=VOdqAAAAMAAJ.
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Carter, Benjamin Owen. "Novel Crystalline Framework Materials." Thesis, University of Liverpool, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486450.
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This t.hesis describes the synthesis and characterisation of metal-organic framework matenals based on cobalt and nickel salts with rigid organic ligands. 'It also contains an account of synthetic and catalytic work towards the incorporation of rhodium into existing frameworks. Chapter 1 provides an introduction to the topic, covering background on the zeolites, an account of the development of frameworks and their applications in modern chemistry, and specific examples relating to the novel frameworks described in later chapters. Chapter 2 covers the synthetic and analytical techniques used to prepare and characterise these materials. ' Chapter 3 describes the detailed crystal structures of five entirely novel frameworks based upon nickel salts and bipyridylligands (4,4'-bipyridine (bipy) and 1,4bis( 4-pyridyl)benzene (3RB». Nickel (II) nitrate and 3RB combine under solvothermal conditions to produce a dense material formed of herringbone layers, [Nb(N03M3RBh] (BC160), with no extra-framework voids. The substitution of nickel nitrate for the equivalent sulphate, combined with room temperature diffusion techniques gives rise to an inclined interpenetrated phase of cross-linked dimer chains, [Nb(S04h(3RBh(H20)] • 2(CH30H) • 3(H20) (BC261). This material displays a 49% extra-framework volume, but suffers from an instability to guest loss. The use of bipy in place of 3RB under similar conditions generates a three-dimensional array of Ni-bipy square grids, pillared by sulphate anions, [Ni(S04)(bipYh] • 3(MeOH) • 3(H20) (BC402). The uniform channels running through the infinite lattice impart an extra-framework volume of 50%. However, given the presence of an irremovable impurity in the as-made crystalline phase, this material presents no opportunities to explore its porous applications. The use of microwave solvothermal techniques produces a new crystalline material, a possible precursor for BC402 above based on the same reactants, [{Ni(bipy)(S04h(H20h} {Ni(bipy)(H20)4} • Bipy] • 3(H20) (BC482). The dense crystal structure comprises two species of one-dimensional chain, which stack in alternating layers along with unbound intercalating bipy molecules. The material possesses no void spaces, and will not undergo phase transition to the BC402 structure. Finally, chiral aspartic acid (Asp) is combined with nickel nitrate and 3RB under solvothermal conditions to form an extended analogue of a bipy-based structure, Nb(L-Asph(3RB)· x(3RB) (BC533_3). Despite a 19% extra-framework volume, this material possesses unbound 3RB occupying its channels. Chapter 4 explores two routes toward catalytic heteronuclear rhodium frameworks. (1) Solvothermal doping of rhodium dimers into CU3(btch(H20h (H3btc = 1,3,5-benzenetricarboxylic acid). Catalytic activity toward the hydrogenation of 1-hexene is investigated, and turnover frequency in the doped frameworks reaches 0.15 molhexane/ mol-Rh/hr. (2) Synthesis of rhodium terephthalate paddlewheel units into existing metal carboxylate frameworks. Discrete paddlewheels are produced, and room temperature and solvothermal techniques toward new heteronuclear frameworks are explored. Chapter 5 covers the synthesis of a further five novel frameworks, based upon a (10,3)-a network topology. New materials are synthesized solvothermally from cobalt nitrate, btc, methyl-pyridines and 1,2-propanediol (1,2-pd) as analogues to existing nickel frameworks, producing four-fold and two-fold interpenetrating nets: C03(btch(4picolineM1,2- pd)6 (BC144) and COJ(btch(3-picoline)&(1,2-pdh (BC143) respectively. Further variations on BC143 are explored through the use of alternative pyridines (resulting in the successful synthesis of Nh(btch(3-ethylpyridine)6(1,2-pdh (BC198» and diols, producing C03(btch(3-picolineM1,2-pentanediolh (BC173) and C03(btch(3picoline) 6(1,2-hexanediolh (BC174). The final two frameworks possess channels functionalised by diol alkyl chains, with a subsequent reduction in void volume.
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Bream, Brendan R. "Tectonic implications of para- and orthogneiss geochronology and geochemistry from the southern Appalachian crystalline core." VIEW WEB VERSION, 2003. http://etd.utk.edu/2003/BreamBrendan.pdf.
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Thesis (Ph. D.)--University of Tennessee, Knoxville, 2003.Title from title page screen (viewed Nov. 11, 2003). Thesis advisor: Robert D. Hatcher. Document formatted into pages (xiii, 296 p. : col. ill., col. maps). Vita. Includes bibliographical references.
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Al-Meshal, Mohammed A. S. "Physicochemical and tableting properties of crystallised and spray-dried phenylbutazone containing polymeric additives : effect of polymeric additives (hydroxypropyl methylcellulose and a polyoxyethylene-polyoxypropylene glycol) on the crystalline structure, physicochemical properties and tableting behaviour of crystallised and spray-dried phenylbutazone powders." Thesis, University of Bradford, 1985. http://hdl.handle.net/10454/4207.
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The physicochemical properties of a drug affect to a large extent its subsequent biological absorption and bioavailability profile. Considerable pharmaceutical interest is therefore directed torwards the improvement of drug dissolution characteristics of drugs with low aqueous solubility. This thesis has considered the controlled modification of drug dissolution profiles by means of incorporating low concentrations of hydrophilic polymers by different processes into a host drug substance. In order to examine this approach and its potential use, the physicochemical, solid state, stability and tableting properties of a poorly aqueous soluble drug, phenylbutazone, in alternative polymorphic form and containing low levels of two hydrophilic polymers - hydroxypropyl methylcellulose (H.P.M.C.) and the surfactant poloxamer 188 - prepared by both conventional crystallisation and spray drying are reported. As an integral nart of the work attempts were mado to identify the different polymorphic forms of phenylbutazone. The δ-form, the commercially available stable form and the α and β metastable forms (nomenclature after Muller, 1978) were isolated. The α form was found to be unstable on storage. A 2 fold increase in intrinsic dissolution rate was observed for the metastable β-polymorph compared with the stable δ-polymorphic form. The effect of crystallisation rate on the formation of polymorphs of phenylbutazone was studied using a mini-spray dryer, and slower rates of crystallisation were found to favour polymorph formation. The hydrophilic polymers, H.P.M.C. and poloxamer 188, were incorporated by conventional crystallisation and spray drying into the drug crystal. Samples were subjected to a series of tests including differential scanning calorimetry, X-ray powder diffraction, scanning electron microscopy, and intrinsic dissolution and solubility. When prepared by conventional crystallisation H.P.M.C. was found to form a "high energy" complex with phenylbutazone which melted 10°C lower than the parent drug. When prepared by spray drying H.P.M.C. inhibited the formation of the metastable β-polymorph of phenylbutazone. A 2 fold increase in intrinsic dissolution rate was observed for crystallised and spray dried samples containing 2% w/w or more added polymer. Poloxamer 188 did not form a complex with phenylbutazone and unlike H.P.M.C. did not inhibit the formation of the β-polymorph. For both crystallised and spray dried samples a 3 fold increase in dissolution rate was obtained at polymer levels of 1% w/w or above. The increase in dissolution has been attributed to facilitated wetting by lowering of interfacial tension rather than through the formation of micelles. The stability of selected phenylbutazone:polymer samples was tested at elevated temperatures. The stability was found to be affected both by the method of sample preparation and the type of additive. Large breakdowns occurring by a hydrolytic effect were identified for the crystallised phenylbutazone samples containing poloxamer 188. The effects on compaction of phenylbutazone in alternative form and presence of polymeric additives were studied by compressing samples of similar particle sizes of phenylbutazone as supplied (δ-form), samples of spray dried phenylbutazone (β-form) and samples containing different concentrations of H.P.M.C. prepared both by conventional crystallisation and spray drying. Compaction data were analysed according to the Heckel relationship and by force transmission ratio as well as from the tensile strengths of prepared tablets. The presence of H.P.M.C. up to 5% w/w concentration in phenylbutazone did not change the mean yield pressure for the crystallised or spray dried samples, although a difference in mean value was observed between the crystallised and spray dried materials, 93.22 MPa and 147.02 MPa respectively. Force transmission was found to be improved for samples containing H.P.M.C. prepared by both techniques and in general, the tablet tensile strengths for crystallised samples containing H.P.M.C. were approximately three times greater than for spray dried samples at equivalent tablet porosity. Differences are attributed to variation in solid state and particulate properties between samples.
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Wang, Haopeng. "Confined crystallization, crystalline phase deformation and their effects on the properties of crystalline polymers." Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1246041849.
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Jones, Catherine Elizabeth. "Studies of the crystalline lens using magnetic resonance imaging." Queensland University of Technology, 2004. http://eprints.qut.edu.au/15950/.
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The eye lens grows continuously throughout life and changes its shape as the eye changes focus from a distant to a near object (the process of accommodation). These changes are complex because they may affect not only the shape of the lens, but also its refractive index distribution. To date there has been no satisfactory technique for directly and non-invasively measuring these changes. In this study the refractive index distribution through the isolated lens was measured non-invasively using a novel MRI technique. The dependence of the refractive index value of lens tissue on its transverse relaxation rate (R2) was determined empirically from measurements on lens homogenate samples. Using a multi-spin-echo imaging sequence, data were acquired for constructing R2 maps of a central slice through the isolated lens. These R2 maps were transformed to refractive index maps using the empirically determined dependence of refractive index on R2. Using a standard algorithm for ray tracing through gradient index media, the propagation of light rays through the index map were simulated. The optical properties of the lens, such as focal length, were then measured. The technique was validated by also directly measuring the focal length of each lens using laser ray tracing. The subtle changes in refractive index distribution that are responsible for the dramatic change in the optical properties of the isolated lens with age, were observed for the first time. The decrease in surface power of the isolated lens with age accounted only partially for the decrease in total lens power with age, the remainder resulting from a reduction in the gradient of refractive index (GRIN) power. It is likely that this reduction in GFUN power is the mechanism by which the eye maintains emmetropia (good distant vision) with age despite the increasing curvature of its surfaces. The reduction in the GRIN power of the lens was found to be mainly due to a flattening of the refractive index profile in the central region of the lens, accompanied by steepening of the profile near the edge of the lens. In agreement with a previous MRI study of the isolated human eye lens, this study found a decrease in the refractive index of the nucleus with age. However the age related change in this study was not as large and not found to be statistically significant. The results demonstrate that existing simple models for the optics of the eye lens are inadequate to accurately describe its properties. Several more sophisticated models were considered in an attempt to describe better the age-dependent changes that occur in both the power of the lens and its longitudinal aberration. Mathematical modelling was also used to simulate the accommodative process and investigate possible changes in the index distribution of the lens that may occur with accommodation. A preliminary in vivo study was performed aimed at observing the change in the refractive index distribution of the eye lens with age and accommodation. These results demonstrated the feasibility of the technique for in vivo applications and showed that within experimental error there is little change in the central refractive index of the lens with age. However the resolution achievable with standard clinical imaging sequences and signal detection hardware was not optimal for in vivo refractive index mapping of changes in the human eye lens with accommodation. Finally therefore, methods for refining the technique for in vivo applications are discussed which may make it possible to directly and simultaneously measure both the shape and refractive index distribution of the lens with age and accommodation.
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Schweitzer, Janet. "Structural evolution of crystalline lower plate rocks, Central Sacramento Mountains, Southeastern California /." This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-10022007-144516/.
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Wild, Janine Helen. "Nematic liquid crystals for use in flexoelectric display devices." Thesis, University of Hull, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273738.
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Lederer, Kay. "Crystalline assemblies of folded oligomers." [S.l. : s.n.], 1999. http://ArchiMeD.uni-mainz.de/pub/2000/0036/diss.pdf.
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Piermattei, Alessio. "Liquid crystalline hydrogen-bonded rosettes." Enschede : University of Twente [Host], 2007. http://doc.utwente.nl/57859.
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Cooper, Kevin L. "Liquid crystalline multi-block copolymers." Diss., This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-05222007-091335/.
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Marshall, Susan Hammond. "Crystalline representations and Neron models." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/290212.
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We define and study the maximal crystalline subrepresentation functor, Crys(-), defined on p-adic Galois representations of the absolute Galois group of a finite extension K of Q(p) . In particular, we define and study the derived functors, Rⁱ Crys(-), of Crys(-). We then apply these functors to the study of Neron models of abelian varieties defined over K. We extend a formula of Grothendieck expressing the component group of a Neron model in terms of Galois cohomology. The extended formula is only valid for abelian varieties with semistable reduction defined over an unramified base. We explore the failure of the formula in the non-semistable case through the example furnished by Jacobians of Fermat curves.
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Tronconi, Alvaro Luiz. "Magnetic resonance in crystalline solids." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329981.
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Twyman, Jonathan Mark. "NMR studies of crystalline penicillins." Thesis, University of Oxford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330066.
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Folwill, Yannick [Verfasser], Hans [Akademischer Betreuer] Zappe, and Ingo [Akademischer Betreuer] Breunig. "Integrated liquid crystalline micro-muscles." Freiburg : Universität, 2021. http://d-nb.info/1229835024/34.
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Jauß, Thomas [Verfasser], Harald [Akademischer Betreuer] Hillebrecht, Arne [Akademischer Betreuer] Cröll, and Michael [Akademischer Betreuer] Fiederle. "Particle incorporation in crystalline silicon." Freiburg : Universität, 2016. http://d-nb.info/1125905689/34.
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Purkiss, Andrew Gordon. "The stability of #gamma#-crystallins." Thesis, Birkbeck (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271285.
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Foulger, Stephen Hans. "Molecular simulation of liquid crystalline." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/11246.
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Lu, Fuyan. "Topological Phases with Crystalline Symmetries." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1524790822570583.
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Ueda, Yasuji. "MONOCLONAL ANTIBODIES TO CHICK CRYSTALLINS." 京都大学 (Kyoto University), 1989. http://hdl.handle.net/2433/86412.
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Park, Seung Chul. "Study of optical properties of multi-crystalline Si and of heavily dislocated single-crystalline Si." Thesis, King's College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314286.
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Schäfer, Heike. "Untersuchung der Proteinalterung am Beispiel des [alpha]A-Crystallins [alphaA-Crystallins] der Augenlinse mittels proteomanalytischer Methoden." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972090770.
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Wilke, Franziska Daniela Helena. "Quantifying crystalline exhumation in the Himalaya." Phd thesis, Universität Potsdam, 2010. http://opus.kobv.de/ubp/volltexte/2010/4313/.
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In 1915, Alfred Wegener published his hypotheses of plate tectonics that revolutionised the world for geologists. Since then, many scientists have studied the evolution of continents and especially the geologic structure of orogens: the most visible consequence of tectonic processes. Although the morphology and landscape evolution of mountain belts can be observed due to surface processes, the driving force and dynamics at lithosphere scale are less well understood despite the fact that rocks from deeper levels of orogenic belts are in places exposed at the surface. In this thesis, such formerly deeply-buried (ultra-) high-pressure rocks, in particular eclogite facies series, have been studied in order to reveal details about the formation and exhumation conditions and rates and thus provide insights into the geodynamics of the most spectacular orogenic belt in the world: the Himalaya. The specific area investigated was the Kaghan Valley in Pakistan (NW Himalaya).
Following closure of the Tethyan Ocean by ca. 55-50 Ma, the northward subduction of the leading edge of India beneath the Eurasian Plate and subsequent collision initiated a long-lived process of intracrustal thrusting that continues today. The continental crust of India – granitic basement, Paleozoic and Mesozoic cover series and Permo-Triassic dykes, sills and lavas – has been buried partly to mantle depths. Today, these rocks crop out as eclogites, amphibolites and gneisses within the Higher Himalayan Crystalline between low-grade metamorphosed rocks (600-640°C/ ca. 5 kbar) of the Lesser Himalaya and Tethyan sediments. Beside tectonically driven exhumation mechanisms the channel flow model, that describes a denudation focused ductile extrusion of low viscosity material developed in the middle to lower crust beneath the Tibetan Plateau, has been postulated. To get insights into the lithospheric and crustal processes that have initiated and driven the exhumation of this (ultra-) high-pressure rocks, mineralogical, petrological and isotope-geochemical investigations have been performed. They provide insights into 1) the depths and temperatures to which these rocks were buried, 2) the pressures and temperatures the rocks have experienced during their exhumation, 3) the timing of these processes 4) and the velocity with which these rocks have been brought back to the surface.
In detail, through microscopical studies, the identification of key minerals, microprobe analyses, standard geothermobarometry and modelling using an effective bulk rock composition it has been shown that published exhumation paths are incomplete. In particular, the eclogites of the northern Kaghan Valley were buried to depths of 140-100 km (36-30 kbar) at 790-640°C. Subsequently, cooling during decompression (exhumation) towards 40-35 km (17-10 kbar) and 630-580°C has been superseded by a phase of reheating to about 720-650°C at roughly the same depth before final exhumation has taken place. In the southern-most part of the study area, amphibolite facies assemblages with formation conditions similar to the deduced reheating phase indicate a juxtaposition of both areas after the eclogite facies stage and thus a stacking of Indian Plate units.
Radiometric dating of zircon, titanite and rutile by U-Pb and amphibole and micas by Ar-Ar reveal peak pressure conditions at 47-48 Ma. With a maximum exhumation rate of 14 cm/a these rocks reached the crust-mantle boundary at 40-35 km within 1 Ma. Subsequent exhumation (46-41 Ma, 40-35 km) decelerated to ca. 1 mm/a at the base of the continental crust but rose again to about 2 mm/a in the period of 41-31 Ma, equivalent to 35-20 km. Apatite fission track (AFT) and (U-Th)/He ages from eclogites, amphibolites, micaschists and gneisses yielded moderate Oligocene to Miocene cooling rates of about 10°C/Ma in the high altitude northern parts of the Kaghan Valley using the mineral-pair method. AFT ages are of 24.5±3.8 to 15.6±2.1 Ma whereas apatite (U-Th)/He analyses yielded ages between 21.0±0.6 and 5.3±0.2 Ma. The southern-most part of the Valley is dominated by younger late Miocene to Pliocene apatite fission track ages of 7.6±2.1 and 4.0±0.5 Ma that support earlier tectonically and petrologically findings of a juxtaposition and stack of Indian Plate units. As this nappe is tectonically lowermost, a later distinct exhumation and uplift driven by thrusting along the Main Boundary Thrust is inferred.
A multi-stage exhumation path is evident from petrological, isotope-geochemical and low temperature thermochronology investigations. Buoyancy driven exhumation caused an initial rapid exhumation: exhumation as fast as recent normal plate movements (ca. 10 cm/a). As the exhuming units reached the crust-mantle boundary the process slowed down due to changes in buoyancy. Most likely, this exhumation pause has initiated the reheating event that is petrologically evident (e.g. glaucophane rimmed by hornblende, ilmenite overgrowth of rutile). Late stage processes involved widespread thrusting and folding with accompanied regional greenschist facies metamorphism, whereby contemporaneous thrusting on the Batal Thrust (seen by some authors equivalent to the MCT) and back sliding of the Kohistan Arc along the inverse reactivated Main Mantle Thrust caused final exposure of these rocks. Similar circumstances have been seen at Tso Morari, Ladakh, India, 200 km further east where comparable rock assemblages occur. In conclusion, as exhumation was already done well before the initiation of the monsoonal system, climate dependent effects (erosion) appear negligible in comparison to far-field tectonic effects.Seit der von Alfred Wegener 1915 postulierten Hypothese der Plattentektonik haben viele Forscher Anstrengungen unternommen die Entstehungsgeschichte und den geologischen Aufbau von Gebirgen nachzuvollziehen. Oberflächennahe Abläufe sind ansatzweise verstanden, während Prozesse im Erdinneren weit weniger bekannt sind. Informationen hierüber können jedoch aus den Gesteinen, ihren Mineralen und wiederum deren chemischen Komponenten gewonnen werden, da diese die Entstehung und Entwicklung der Gebirgsbildung “miterlebt”, und wichtige Informationen gespeichert haben. In dieser Arbeit wurden dazu exemplarisch (Ultra-) Hochdruckgesteine ((U-)HP), sogenannte Eklogite, und deren Umgebungsgesteine aus dem nordwestlichen Himalaja, insbesondere aus dem Kaghan Tal in Pakistan untersucht um den Exhumationsprozess von tief subduzierten Krustengesteinen im allgemeinen, und im Hinblick auf mögliche klimabedingte Einflüsse, besser zu verstehen. Die Bildung des Himalajas ist auf die Versenkung, eines südlich der eurasischen Platte angesiedelten Ozeans, der Tethys, und die nachfolgende Kollision Indiens mit dem Eurasischen Kontinent vor und seit etwa 50-55 Millionen Jahre zurück zu führen. Dabei wurden kalter, dichter Ozeanboden und leichtere Krustensegmente rasch in große Tiefen subduziert. Heute sind diese Hochdruck- und ultra Hochdruckgesteine in einigen Bereichen des Himalaja zwischen schwach metamorph überprägten (600-640°C/ca. 5 kbar) Gesteinen und alten Sedimenten der Tethys aufgeschlossen. Anhand von petrographischen, mineral-chemischen, petrologischen und isotopen-geochemischen Untersuchungen dieser (Ultra) Hochdruckgesteine konnte ich zeigen, dass 1) die Gesteine in über 100 km Tiefe also bis in den Erdmantel vordrangen, 2) sie bei ihrem Aufstieg in Krustenbereiche von 40-35 km zuerst von 790-640°C auf 630-580°C abgekühlten um danach wieder auf 720-650°C aufgeheizt zu werden, sie 3) innerhalb von 700.000 Jahren um mindestens 60 km Richtung Erdoberfläche exhumiert wurden und somit 4) Geschwindigkeiten von 9-14 cm pro Jahr erreichten, die der normaler Plattengeschwindigkeiten (>10 cm/a) entspricht, wobei sich 5) dieser Prozess ab 40-35 km auf 0.1-0.2 cm/a stark verlangsamte und auch 6) ab einer Tiefe von 6 km bis zur Erdoberfläche keine, z. B. niederschlagsbedingt, erhöhte Abkühlungsrate zu erkennen ist. Eine schnelle initiale Exhumierung erfolgte durch den Dichteunterschied von leichtem, subduzierten Krustengestein zum dichteren Mantel. Dieser Prozess kam an der Krusten-Mantel-Grenze nahezu zum erliegen, einhergehend mit einer sekundären Aufheizung des Gesteins und wurde, jedoch weit weniger schnell, durch die Kollision der beiden Kontinente Eurasien und Indien und dadurch bedingte Überschiebungen, Faltungen und gravitative Abschiebungen fortgesetzt, die Gesteine zur Oberfläche transportiert und dort freigelegt. Eine erosions- und damit klimabedingte Beschleunigung oder gar gänzlich davon abhängige kontinuierliche Exhumation konnte in dieser Region des Himalajas nicht bestätigt werden. Vielmehr belegen die Daten eine mehrstufige Exhumation wie sie auch im Tso Morari Gebiet (NW Indien) angenommen wird, für weitere Ultrahochdruckareale wie, z. B. das Kokchetav Massif (Kasachstan), den Dabie Shan (China) oder den europäischen Varisziden (z. B. Böhmisches Massiv) jedoch noch geklärt werden muss, um generell gültige Mantel- und Krustenprozesse abzuleiten.
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Budgell, Derek Richard. "Liquid crystalline properties of ethyl cellulose." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74271.
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The formation and chiroptical properties of liquid crystals of ethyl cellulose (EC) and some related polymers are investigated to determine which features affect the mesophase behaviour.The onset of mesophase formation is studied by employing literature data on the viscosity/molar mass relationship of several cellulose derivatives, including EC in several solvents, to calculate their molecular dimensions by a recent hydrodynamic theory. The phase separation behavior is compared with the predictions of theories for both freely-jointed and wormlike chains.
The effects of solvent and degree of substitution (DS) on the cholesteric structure are assessed by studying the chiroptical properties using Circular Reflectance and Optical Rotatory Dispersion (ORD) techniques. The DS strongly influences the helicoidal twist sense, reflection wavelength and response of the reflection wavelength to changes in temperature. Mesophases and cholesteric films of the methyl and n-butyl derivatives of EC are also investigated. The ORD spectra of isotropic EC solutions are found to be strongly influenced by the solvent employed.
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Dimitrievska, Mirjana. "Crystalline and vibrational properties of kesterites." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/395179.
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The main objective of this thesis is to deepen the knowledge of fundamental properties of kesterite materials (Cu2ZnSnS4 and Cu2ZnSnSe4) and their solid solutions Cu2ZnSn(S,Se)4, which are used as absorber layers in solar cells. This principally included full characterization of structural and vibrational properties of these materials mainly using various Raman spectroscopy techniques. Special focus is put on the investigation of defect dynamics in kesterites, especially on the experimental identification of defects and their effect on the optoelectronic properties and thus the performance of solar cells devices. Additionally, among the objectives of the thesis was development of Raman based methodologies for the compositional assessment of these materials, as well as obtaining more information regarding the fundamental properties of ZnSSe secondary phase. The results were shown in the series of articles which have been published in high impact peer-review journals.
In the first part of the thesis, a complete analysis of all Raman active modes of the stoichiometric Cu2ZnSnS4, Cu2ZnSnSe4 and Cu2ZnSn(S,Se)4 compounds was made using six different excitation wavelengths from near infrared to ultraviolet. Based on the first principle simulations, normal displacements of each Raman mode were calculated and provided insightful knowledge about the involvement of atoms in vibrations corresponding to different modes.
Additionally defect dynamics in kesterite materials was explored. Asymmetry in the shape of the low frequency region of the main Raman modes has been observed for Cu2ZnSnS4 samples with different crystal quality. This has been attributed to phonon confinement effects which are arising from the loss of translational symmetry in the crystal caused by a high density of defects. Based on this model, a simple methodology independent of measuring conditions is proposed for the quantitative assessment of crystal quality through the correlation length. After this, the effect of specific defect clusters on the Raman spectra and optoelectronic properties was investigated. Combinatorial Cu2ZnSnSe4 thin films with lateral compositional gradients were synthesized and made into solar cell devices (around 200 cells per sample), in order to study the correlation between the optoelectronic properties and absorber composition. Furthermore, detailed analysis of the Raman spectra has allowed investigation of the changes in the relative intensity of Raman peaks in relation to the occurrence of different kinds of defect clusters. Finally, the influence of point defects and secondary phases on the performance of Cu2ZnSnSe4 devices was presented.
Last part of the thesis was dedicated to development of a methodology for the quantitative assessment of the anion composition of Cu2ZnSn(S,Se)4 solid solutions using Raman spectroscopy. The methodology is based on the analysis of the integral intensity ratio of Raman bands sensitive to anion vibrations.
Finally, a fundamental study, based on experimental and theoretical investigation, of the Raman resonance effects in ZnSSe solid solutions was presented. The Raman scattering intensities of LO ZnS-like and ZnSe-like phonon modes, corresponding to pure S and Se vibrations, respectively, were revealed to be significantly enhanced when excited with 325 nm excitation in the case of S vibrations, and with 455 nm in the case of Se vibrations. This behavior was explained by the interaction of the excitation photons with the corresponding S or Se electronic states in the conduction band, and further confirmed by first principles simulations.
In conclusion, the works presented in this thesis are a significant contribution to the study of fundamental properties of materials in general, and kesterites materials in particular. Additionally, due to the unique approach of utilizing Raman spectroscopy with other characterization techniques, these methods could prove to be very successful in structure/function studies of other multinary compounds which are gaining increasing interest for electronic applications.El objetivo principal de esta tesis es mejorar el conocimiento de las propiedades fundamentales de los compuestos de kesterita (Cu2ZnSnS4 and Cu2ZnSnSe4) y sus soluciones solidos Cu2ZnSn(S,Se)4 para uso como absorbedor en células solares. Esto constituye de la caracterización completa de las propiedades estructurales y vibracional utilizando la espectroscopia Raman. Adicionalmente, está el desarrollo de metodologías basado en Raman para la valoración composicional de estos materiales. Estos resultados están destacados en una serie de artículos publicados en revistas de peer-review de alto impacto. Un análisis completo de todos los modos activos de Raman de los compuestos estequiometricas de kesterita se realizó utilizando seis diferentes longitudes de onda de excitación, desde el infrarrojo hasta la ultravioleta. A partir de la base de simulaciones de primeros principios, los desplazamientos normales de cada modo Raman fueron calculados y dan un conocimiento útil sobre la participación de átomos en vibraciones correspondientes a diferentes modos. Un énfasis especial se da a la investigación de la dinámica de defectos en las kesteritas, en particular a la identificación experimental de los defectos y sus efectos sobre las propiedades optoelectrónicas, incluso el rendimiento, de dispositivos de células solares. También se desarrollo de una metodología para la valoración quantativa de la composición de aniones de soluciones solidos de Cu2ZnSn(S,Se)4 utilizando la espectroscopia Raman. Esta metodología se basa en la analisis de la intensidad integral de las bandas Raman más sensibles a vibraciones de los aniones. Por último, hay un estudio teórica y experimental del aumento en intensidad de los modos Raman de compuestos ZnSSe, bajo varias condiciones de resonancia, lo cual resulta en una mejora del conocimiento de la parte que juega los estados electrónicos de los calcogenuros en la interacción de fotón-materia. En conclusión, el trabajo presentado en esta tesis es una contribución significante al estudio de las propiedades fundamentales de los materiales en general, y los compuestos de kesterita en particular. Adicionalmente, debido al uso complementario de la espectroscopia Raman con otras técnicas de caracterización, estos métodos puedan resultar en ser muy útiles en estudios de estructura/función de otros compuestos multinarios, los cuales están ganado más interés para aplicaciones electrónicas.
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Bogdanowicz, Krzysztof Artur. "Liquid Crystalline Polymers for Smart Applications." Doctoral thesis, Universitat Rovira i Virgili, 2015. http://hdl.handle.net/10803/321835.
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Polímers cristall-líquids (PCL) posseeixen propietats que són una combinació entre sòlids cristal·lins i fluids. Actualment, PCL que incorporen elements actius en l'estructura (pe, grups de foto-sensibles, dendrons, etc.) condueixen a un material selectivament sensible. S'informa que els polímers es poden aplicar en diversos sistemes pe com materials amb memòria de forma, sensors o pantalles foto-òptiques. Els nostres estudis se centren en dues aplicacions diferents: microcàpsules fotosensibles per a sistemes de lliurament controlat i les membranes autoacoblades conductores de protons per a la fotosíntesi artificial. La versatilitat i les propietats anisotrópicas de PCL, els fan com a candidats ideals per a nombrosos aplicacions intel·ligents. Per obtenir sistemes amb alliberament foto-activa, una família de copolímers, que conté alfa-estilbè i diferents espaiadors s'han dissenyat i sintetitzat. Alfa-estilbè és un mesogéno foto-actiu. Les microcàpsules basades d'alfa-metilestilbeno, amb vainillina en nucli, estaven preparats. Experiment d'alliberament amb i sense fotoirradiación va demostrar l'eficàcia d'aquest sistema. CLP d'estructura adequada per a auto-acoblament en una estructura columnar que podria ser efectiu en el transport de protons selectiu. Alineació homeotrópica de columnes en una membrana polimèrica permet aconseguir conductivitat de protons. Objectiu del nostre treball va ser: aconseguir estructures organitzades utilitzant poliamines modificades amb un mesógeno dendrític en posició lateral; preparació de membranes orientades usant aquests materials polimèrics; avaluar l'eficàcia de les membranes cap al transport de protons. Es van preparar membranes híbrides de ceràmica / poliamina. El material va mostrar alta conductivitat de protons selectiva i transport aigua-independent.Actualmente, PCL que incorporan elementos activos en la estructura (p.e., grupos de foto-sensibles, dendrones, etc.) conducen a un material selectivamente sensible. Se informa de que los polímeros se pueden aplicar en varios sistemas p.e. como materiales con memoria de forma, sensores o pantallas foto-ópticas. Nuestros estudios se centran en dos aplicaciones diferentes: microcápsulas fotosensibles para sistemas de entrega controlada y las membranas autoensambladas conductoras de protones para la fotosíntesis artificial. La versatilidad y las propiedades anisotrópicas de PCL, los hacen como candidatos ideales para numerosos aplicaciones inteligentes. Para obtener sistemas con liberación foto-activa, una familia de copolímeros, que contiene alfa-estilbeno y diferentes espaciadores se han diseñado y sintetizado. Alfa-estilbeno es un mesogéno foto-activo. Las microcápsulas basadas de alfa-metilestilbeno, con vainillina en núcleo, estaban preparados. Experimento de liberación con y sin fotoirradiación demostró la eficacia de este sistema. CLP de estructura adecuada para auto-ensamblaje en una estructura columnar que podría ser efectivo en el transporte de protones selectivo. Alineación homeotrópica de columnas en una membrana polimérica permite conseguir conductividad de protones. Objetivo de nuestro trabajo fue: lograr estructuras organizadas utilizando poliaminas modificadas con un mesógeno dendrítico en posición lateral; preparación de membranas orientadas usando estos materiales poliméricos; evaluar la eficacia de las membranas hacia el transporte de protones. Se prepararon membranas híbridas de cerámica/poliamina. El material mostró alta conductividad de protones selectiva y transporte agua-independiente.
Liquid Crystalline Polymers (LCPs) possess properties which are a combination of crystalline solids and fluids. Currently, LCPs which incorporate active elements into the structure (i.e. photo-sensitive groups, dendrons, etc.) lead to selectively sensitive material. It is reported, that those polymers can be applied in a variety of systems i.e. as memory-shape materials, sensors or photo-optical displays. Our studies are focused on two different applications: photosensitive microcapsules for controlled delivery systems and self-assembly proton-conducting membranes for artificial photosynthesis. The extreme versatility and the characteristic anisotropic properties of LCPs, make them the ideal candidates for numerous smart applications. To achieve systems with photo-triggered release, a family of copolymers which contained alpha-methylstilbene and different spacers were designed and synthesized. Alpha-methylstilbene is a well-known photo-active mesogenic group. Microcapsules based on alpha-methylstilbene containing vanillin as a core were prepared. Release experiment in the presence and the absence of photoirradiation proved the effectiveness of this system. LC polymers of proper structure self-assembly into a columnar structure which could be effective in selective proton transport. Homeotropic alignment of columns in a polymeric membrane allows to achieve proton-conductivity. Aim of our work was: achieving organized structures using polyamine modified with a dendritic mesogen in side position; preparing oriented membranes based on this polymeric materials;assessing the effectiveness of the prepared membranes toward proton transport. Hybrid ceramic/polyamine membranes were prepared. The new material showed high selective proton conductivity and water independent transport.
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Nedimovic, Mladen R. "Seismic reflection imaging in crystalline terrains." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq53838.pdf.
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Molster, Frans Johan. "Crystalline silicates in circumstellar dust shells." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/91412.
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Contoret, Adam Edward Alexander. "Liquid crystalline networks for electroluminescent displays." Thesis, University of Hull, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395931.
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Kitney, Stuart Paul. "Liquid crystalline semiconductors for organic electronics." Thesis, University of Hull, 2008. http://hydra.hull.ac.uk/resources/hull:757.
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This research is based on the synthesis and evaluation of novel liquid crystalline materials with light-emitting and or charge-transporting properties. Some of the liquid crystals (LCs) synthesised incorporate photopolymerisable diene or methacrylate end groups, situated at the peripheries of the molecular core. These photoreactive liquid crystalline monomers are often termed reactive mesogens. The generation of linearly and circularly polarised light emission have been observed and a White-Light Organic Light-Emitting Diode (WOLED) fabricated from binary mixtures of LCs. A series of fluorene-containing LCs have been synthesised for use as hole-transport, electron-transport and electroluminescent materials. Many of these materials exhibit nematic phases, which is beneficial for alignment due to the lower viscosity present in the nematic phase compared to the smectic phase. Columnar LCs with low melting points were synthesised by variation of the aliphatic groups at the 3,4,9,10-positions of a perylene tetracarboxylate. A fluorene-containing material with perfluorinated chains at the 9-position of the fluorene was synthesised, although the required LC phase was not observed. High electron-affinity nitrogen-containing smectic LCs have been synthesised with relatively low LC transition temperatures. These materials may prove useful as electron-transport materials. An electroluminescent chiral nematic LC was synthesised, which leads to the possibility of circularly polarised light. The possibility of a full-colour LC-Organic Light-Emitting Diode (OLED) has been demonstrated with the synthesis of a red-emitting material, a green-emitting material and a blue-emitting material. All three materials are LCs with high glass transition temperatures, which is important for device stability as these materials are not reactive mesogens. A White-Light OLED has been demonstrated by the mixing of two LCs. This nematic binary mixture when used as the emissive layer in an OLED emits white-light that is voltage independent and not due to Förster energy transfer. Consequently this mixture can be aligned and linearly polarised light emission has been generated with a 9:1 ratio. A series of perylene-containing LCs have been synthesised for use as electron-transport materials in OLEDs or electron-acceptors in organic photovoltaics.
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Johnson, Roger Douglas. "Magnetism in crystalline rare-earth compounds." Thesis, Durham University, 2011. http://etheses.dur.ac.uk/589/.
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In this thesis we investigate the magnetism of a selection of crystalline mate- rials that display fascinating macroscopic properties, largely due to the complex behaviour of rare-earth ions. The technique of choice is diffraction; shown to pro- vide the most lucid of results in this field of research. Neutron powder diffraction, a well established tool for determining magnetic structures, has been employed in order to determine two magnetic structures of the intermetallic R2CoGa8 series. This was the first such study of these materials, which are of great interest as the magnetic exchange interactions of the rare-earth ions compete with the crystal elec- tric field, giving rise to a wealth of magnetic properties tuneable by the choice of rare-earth ion. We then move on to study two of the most extreme multiferroic mate- rials, TbMn2O5 and TmMn2O5. We have developed a new technique for determin- ing electronic state specific magnetic structures through resonant x-ray diffraction, which we have successfully employed in an investigation of the terbium magnetic sub-lattice in TbMn2O5. The outstanding question in many multiferroics regards the exact microscopic mechanisms at play. Due to the huge potential in technology, this has been the subject of intense debate over that past decade. We have shown, through ab-initio computation and the simultaneous measurement of electric polar- isation and magneto-striction, that the exchange-striction model is dominant in the main ferroelectric phase of TbMn2O5 and TmMn2O5. Through ion specific resonant x-ray diffraction measurements, we have clarified the behaviour of the terbium sub- lattice upon the magnetic field induced electric polarisation reversal in TbMn2O5. Furthermore, we have made the discovery of additional incommensurate magnetic diffraction signals, believed to be indicative of the response of magnetic domains to applied magnetic fields.
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Lovell, Christopher Stewart. "High performance bioresorbable liquid crystalline polymers." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511134.
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McLaren, Sholto Riley Martin. "CPI induced discotic liquid crystalline systems." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.515549.
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Collier, A. P. "High resolution imaging of crystalline agglomerates." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597853.
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A novel method of forming pure calcite seed materials by nucleation from an alkaline solution was developed. Batch experiments were conducted to investigate the growth and agglomeration rates of the calcite seed particles under varying agitation rates. Stirrer speeds between 700 and 2000 rpm were studied. The experiments were all carried out in a saline solution of ionic strength 0.153 M, with an initial supersaturation of approximately 4.0. The data from the experiments were analysed using the program Batch (Hounslow, 1990). This program extracts growth and agglomeration rates from the changes observed in particle size distributions with time. It is found that the growth rate is independent of the crystal size and the agitation rate. Growth rates from all experiments can be expressed by a single equation with a second order dependence of the growth rate on the supersaturation. This dependence, and the magnitude of the growth rate constant are consistent with other reports in the literature. The agglomeration rate is best described by a size-independent agglomeration kernel. At all except the lowest stirrer speed, the agglomeration rate is found to be proportional to the growth rate. The agglomeration rate is found to decrease as the stirrer speed increases. Correlation of the agglomeration rate with the stirrer speed shows that the agglomeration rate is proportional to the stirrer speed raised to the (-1.5) power. A comparison with estimates for the average shear rate within a stirred vessel suggest that the agglomeration rate is inversely proportional to the average shear rate within the crystalliser. Microscopic examination of many calcite samples was undertaken with SEM systems. Several hundred images of calcium carbonate particles were obtained. High resolution images were used to identify the phases present in preliminary trials, and to confirm that the calcite was the main product of the batch growth experiments. Images of samples taken from the batch growth experiments were used to confirm the decrease in the agglomeration rate at higher stirrer speeds, and the constancy of the growth rate. No evidence was found for any preferential alignment of the crystallites within the agglomerates produced by this method.
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Hinchcliffe, Trevor Thomas. "Chiral side chain liquid crystalline polymers." Thesis, Heriot-Watt University, 1993. http://hdl.handle.net/10399/1404.
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King, Amy Sarah Helen. "Synthetic studies toward novel crystalline dendrimers." Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327493.
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Bateman, Orval. "The characterisation of eye lens crystallins." Thesis, Birkbeck (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301285.
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