Mesoporous nanocrystalline zirconia with lamellar and MSU structure

Without introduction of any stabilizer, the mesoporous nanocrystalline zirconia with lamellar and MSU structure was obtained via solid state reaction coupled with surfactant templating method. The phase, surface area and pore structure of zirconia prepared with this novel method could be designed, tailored and controlled by varying synthesis parameters. The phase transformation was controlled by particle size. The mesostructure possesses nanocrystalline pore wall, which renders it more thermally stable than amorphous framework. The results suggest strongly that in solid state synthesis system mesostructure formation still follow the supramolecular self-assembly mechanism. The lamellar and reverse hexagonal structure could be transformed at different OH-/Zr molar ratios in order to sustain the low surface energy of the mesophases. The lamellar structure was preferred at higher OH-/Zr molar ratios but reverse hexagonal was at low ratios.

Synthesis and stabilization of nanocrystalline zirconia with MSU mesostructure

In the presence of nonionic block-copolymer surfactant, nanocrystalline zirconia particles with MSU mesostrucmre were synthesized by a novel solid-state reaction route. The zirconia particles possess a nanocrystalline pore wall, which renders higher thermal stability compared to an amorphous framework. To further enhance its stability, laponite, a synthetic clay, was introduced. Laponite acts as an inhibitor to crystal a growth and also as a hard template for the mesostructure. High surface area and ordered pore structure were observed in the stabilized zirconia. The results show that the formation of the MSU structure is attributed to reverse hexagonal micelles, which are the products of the cooperative self-assembly of organic and inorganic species in the solid-state synthesis system with crystalline water and hygroscopic water present.

The organ : writings and other utterances on its structure, history, procural, capabilities, etc. ; with criticisms, and depositories; preceded by an analytical consideration of general bibliographical and catalogual construction /

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New dimeric supramolecular structure of mixed (phthalocyaninato)(porphyrinato)-europium(III) sandwiches : preparation and spectroscopic characteristics

The mixed double-decker Eu\[Pc(15C5)4](TPP) (1) was obtained by base-catalysed tetramerisation of 4,5-dicyanobenzo-15-crown-5 using the half-sandwich complex Eu(TPP)(acac) (acac = acetylacetonate), generated in situ, as the template. For comparative studies, the mixed triple-decker complexes Eu2\[Pc(15C5)4](TPP)2 (2) and Eu2\[Pc(15C5)4]2(TPP) (3) were also synthesised by the raise-by-one-story method. These mixed ring sandwich complexes were characterised by various spectroscopic methods. Up to four one-electron oxidations and two one-electron reductions were revealed by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). As shown by electronic absorption and infrared spectroscopy, supramolecular dimers (SM1 and SM3) were formed from the corresponding double-decker 1 and triple-decker 3 in the presence of potassium ions in MeOH/CHCl3.

Influence of host plant structure and microclimate on the abundance and behaviour of Tephritid fly

Microclimate and host plant architecture significantly influence the abundance and behavior of insects. However, most research in this field has focused at the invertebrate assemblage level, with few studies at the single-species level. Using wild Solanum mauritianum plants, we evaluated the influence of plant structure (number of leaves and branches and height of plant) and microclimate (temperature, relative humidity, and light intensity) on the abundance and behavior of a single insect species, the monophagous tephritid fly Bactrocera cacuminata (Hering). Abundance and oviposition behavior were signficantly influenced by the host structure (density of foliage) and associated microclimate. Resting behavior of both sexes was influenced positively by foliage density, while temperature positively influenced the numbers of resting females. The number of ovipositing females was positively influenced by temperature and negatively by relative humidity. Feeding behavior was rare on the host plant, as was mating. The relatively low explanatory power of the measured variables suggests that, in addition to host plant architecture and associated microclimate, other cues (e.g., olfactory or visual) could affect visitation and use of the larval host plant by adult fruit flies. For 12 plants observed at dusk (the time of fly mating), mating pairs were observed on only one tree. Principal component analyses of the plant and microclimate factors associated with these plants revealed that the plant on which mating was observed had specific characteristics (intermediate light intensity, greater height, and greater quantity of fruit) that may have influenced its selection as a mating site.