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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 311 to 320 of 2206 (0.026 seconds)Spelling suggestions: "subject:"crystals"" "subject:"3crystals""
| 311 |
The synthesis and characterization of thermotropic compounds for rim-type polymers.Hoshino, Hiroshi 01 January 1982 (has links) (PDF)
Several hydroxy-terminated, low molecular weight polymers were reacted to form esters bearing mesogenic endgroups. The effect of the different repeating unit structures with a common mesogenic unit based on an oxybenzoylterephthalate dyad ester on the formation and properties of liquid crystals was studied by microscopic and thermal analysis techniques. The polymeric glycols used were polyethylene glycols (PEG), polytetramethyl ene glycols (PTMG), polybutadiene glycol (PB), and hydrogenated polybutadiene glycol (HPB) with molecular weight of 650 ^ 6000, in addition to 1 ,12-dodecanediol for the model compound. Conversion of the mesogenic dyad ester to a dyad containing a carboxylic acid group was shown to permit mesophase formation over a wide temperature range. The HPB product of this series was found to be a liquid crystalline elastomer with a low viscosity above the melting point, and with film forming ability. On examining the effect of endgroups on physical properties, it was found that both the length v of mesogen and hydrogen bonding interaction by carboxyl groups proved to be the most important factors to form liquid crystals with the PB and HPB polymers. Texture observation of macroglycol products on a polarizing microscope gave neither sharp T.. (clearing temperature) nor typical pattern of mesomorphic state. This result may be explained on the basis of the low stability of liquid crystal phase. These results were consistent with the differential scanning calorimetry (DSC) measurement that showed isotropic transition endotherms on heating but no peak on cooling. Low molecular weight precursors with liquid crystalline end groups associate to form high molecular weight polymers which resulted in films. Until now physical properties have been poor, but there is a possibility that further research in this area might provide a route to useful polymers which could be adaptable to the RIM process.
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| 312 |
Nonreciprocal optical scattering of liquid crystal domains /Sun, Yuh-Guin January 1987 (has links)
No description available.
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| 313 |
The energetics and symmetry of quasicrystals /Narasimhan, Subha January 1987 (has links)
No description available.
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| 314 |
Dislocation substructure formed during creep in molybdenum single crystals /Clauer, Allan H. January 1968 (has links)
No description available.
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| 315 |
A study of the crystal structure of Långbanite /Crane, Robert Lee January 1969 (has links)
No description available.
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| 316 |
The influence of surface charge and surface structure on the sublimation of ionic crystals.Short, David Winfield January 1972 (has links)
No description available.
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| 317 |
The effects of electric, magnetic and acoustic fields on the optical and NMR properties of the nematic liquid crystal P-methoxy benzylidene P-N-butylaniline /Mailer, Hugh January 1973 (has links)
No description available.
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| 318 |
Magnetic properties of crystalline Mg:Mn /Garvin, Richard Wesley January 1978 (has links)
No description available.
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| 319 |
An analysis of the high temperature plastic flow of polycrystalline copper /Cadien, Kenneth Charles. January 1976 (has links)
No description available.
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| 320 |
Observations and model calculations of ice crystal growthStrapp, J. Walter. January 1977 (has links)
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