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Showing 1 to 20 of 26 for “"sol-gel processing"”.
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Investigations of the early stages of titania sol-gel processing
… (OPr$\sp{\rm i})\sb{18}$ as the sole product in solution. Reaction of Ti(OPr$\sp{\rm i})\sb4$ with one equivalent of water in isopropanol at 100$\sp\circ$C for 3 days yielded as the sole products a 1:1 mixture of two isomeric complexes, $\alpha\sb1$- (Ti$\sb{12}$O$\sb{16}$) …
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Sol-gel processing of RxY3-xAlyFe5-yO12 magneto-optical films
… Accomplishment of this task was achieved via sol-gel processing of rare-earth and aluminum substituted yttrium-iron garnet (RxY3-xAlyFe5-yO12, R,Al:YIG), where R= Bi, Gd, Er, Ho. Detailed are the processing conditions, parameters and results leading to R,Al:YIG films with MO response. Success …
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Fabrication of Random Hole Optical Fiber Preforms by Silica Sol-Gel Processing
Conventional fibers are comprised of a solid glass core and solid glass cladding often protected by a thin polymer sheath. The finely tuned difference in refractive indices, for step index-fibers, is achieved by doping the core with germanium or elements with similar effects. Holey fibers …
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The Development of Alkoxy-Based Sol -Gel Processing for Magnetoresistive Manganite Thin Films
The cubic lattice parameters of the films (i.e., a = ∼ 3.90 A) were in excellent agreement with values published in the literature for bulk, polycrystalline powders. Typical grain sizes started at 10--15 nm, increasing to 20--25 nm by 750°C. For films deposited on Si(100), magnetoresistance …
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The development of alkoxy-based sol-gel processing for magnetoresistive manganite thin films
… successful development of an all-alkoxy based, sol-gel process for integrating thin films of magnetoresistive doped-lanthanide manganites onto silicon-based substrates. Crystallization of the requisite perovskite phase at temperatures below 650°C resulted from the incorporation of all-alkoxide …
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Sol-gel processing, perovskite phase development and properties of relaxor-based thin layer ferroelectrics
… for capacitor and ferroelectric applications. Sol-gel methods were used to prepare thin layers by spin-casting partially hydrolysed alkoxide-based solutions on platinized Si substrates. As-deposited layers were amorphous, and formed a nonferroelectric pyrochlore phase or a ferroelectric …
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Phase development and texture for lead-based perovskite thin layers prepared by sol-gel processing
… the development of texture were investigated for sol-gel derived lead-based perovskite thin layers. Dielectric and ferroelectric properties were examined in terms of crystal structure, microstructure, and preferred orientation. Ferroelectric La-modified Pb(Zr,Ti)O$\sb3$ (PLZT) and …
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Fabrication and characterization of hollow silica aerogel spheres using sol-gel processing in the dual nozzle generation system
… for fabricating uniform, hollow silica aerogel spheres of controlled size, thickness, and porosity that may be required for manufacture of cryogenic ICF (Inertial Confinement Fusion) Targets. The method was a combination of a droplet generation method and sol-gel processing. The parameters …
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Evolution of molecular structure during the sol-gel processing of lithium niobate and the development of microstructure in alkoxide-derived thin layers
… niobate powders and thin-layers were prepared by sol-gel processing. Lithium niobium ethoxide and lithium niobium methoxyethoxide bimetallic alkoxides were used for both gel and thin-layer formation. Advantages of sol-gel processing were demonstrated by synthesis of …
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Preparation of silica aerogels with improved mechanical properties and extremely low thermal conductivities through modified sol-gel process
Reported silica aerogels have a thermal conductivity as low as 15 mW/mK. The fragility of silica aerogels, however, makes them impractical for structural applications. The purpose of the study is to improve the ductility of aerogels while retain the low thermal conductivity of silica aerogels. We …
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Evolution of local structure and stress development during thermal treatment of sol-gel-derived PZT-based thin layers
… the deposition of ferroelectric thin layers by sol-gel processing. However, to sustain further improvements in the technique necessary for widespread applications, a systematic approach to the study of physical, chemical and structural changes that occur during transformation from the …
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Chemical processing of lead metatitanate by co-precipitation and sol-gel methods: The role of powder and gel characteristics on crystallization behavior
… co-precipitation and (ii) organo-metallic sol-gel processing. The effects of chemical processing conditions on material properties were determined. Particular attention was paid to the evolution of structure on heat treatment, and crystallization. Materials prepared by the two methods were …
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Effects of solid solution on the high-low inversion of cristobalite and the stabilization of high cristobalite
… and BPO₄ into the cristobalite phase using solid state reactions. The combination of TiO₂ and AlPO₄ proved to be most effective in lowering the inversion temperature of cristobalite. Phase diagrams at the high silica corner were constructed for the respective systems. High cristobalite was …
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Microwave heating of a coating on a temperature-sensitive substrate
… could be performed with available equipment. Sol-gel processing of a 1Microwave heating has been considered for the heating of a coating in contact with a temperature-sensitive substrate. A methodology was developed to conduct a microwave heating feasibility study for a candidate system. The …
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Thermal expansion of chemically modified mullite
Solid-state reaction and sol-gel, processing techniques were used extensively to form chemically-modified mullite solid solutions in an effort to lower their thermal expansion coefficients. TiO₂, B₂O₃, CrPO₄, P2O₅, Ga₂O₃, Cr2O₃, and WO₃ and the half-breed SiO₂ compounds AlPas, BPO₄, GaPO₄, BAsO₄, …
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Thermal expansion and thermal conductivity of (Ca<sub>1-x</sub>,Mg<sub>x</sub>)Zr₄(PO₄)₆ where x = 0.0-0.4
Solid-state reaction and sol-gel processing methods were used to prepare samples of (Ca<sub>1 - X,</sub>Mg<sub>X</sub>)Zr₄(PO₄)₆(CZP-CMZP) where x = 0.0-0.4. CMZP is a member of the NaZr₂(PO₄)₃ (NZP) class of ceramics and is being investigated for heat engine applications. Linear thermal expansion …
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Eu3+ pakeistų Y3Ga5O12 granatų sintezė ir liuminescencinių savybių tyrimas /
… of powder samples were synthesized by citric sol—gel processing route. The concentration of dopant Eu3+ in every compound was 5 %, 10 %, 15 %, 20 %, 25 %, 30 %, 50 %, 75 %, 100 %. According to the XRD data all co-doped garnets are single phase. SEM photos by scanning electron microscope FE-SEM …
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Structure Evolution of Silica Aerogel under a Microwave Field
Structure evolution of silica aerogel was studied in microwave- and conventionally processed samples over the temperature range from 25 to 1200â °C. The samples were produced using sol-gel processing and dried under carbon dioxide supercritical conditions. After drying, the monolithic samples …
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Use of a quartz crystal microbalance to investigate the mechanical stability of silica xerogel membranes for volatile iodine capture
… the capture of radioiodine off-gassed during the processing of legacy waste or the reprocessing of nuclear waste. While studies investigate their iodine capture efficiency, only limited information about their mechanical applicability is found in the literature. This study investigates mechanical …
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Structure/property behavior of inorganic/organic sol-gel derived hybrid materials
… as CERAMERs have been successfully prepared by a sol-gel process using a polymeric acid catalyst, poly(styrene sulfonic acid), to form a network from tetraethylorthosilicate (TEOS) and triethoxysilane end capped oligomers of poly( tetramethylene oxide) (PTMO). The structure-property relationships …
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