4 research outputs found

    Comparison results of dynamic shift functions.

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    Comparison results of dynamic shift functions.</p

    Comparison of PSOLFWM with other meta-heuristic algorithms using t-Test.

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    Comparison of PSOLFWM with other meta-heuristic algorithms using t-Test.</p

    Optically Active Chiral CuO “Nanoflowers”

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    Helical symmetry can be found in most flowers with a rotation of contort petal aestivation. For micro- and nanoscale analogies, flower mimicking structures have been reproduced; however, the conceptual chirality of “nanoflowers” has not yet been defined. Here, the chirality of the “flower” was defined by its nanosized chiral structure and consequent optical activity (OA), opening new horizons for the physical theory and chiral materials. We report the surfactant-mediated hydrothermal synthesis of chiral CuO nanoflowers using sodium dodecyl sulfate (SDS) as a structure-directing agent, an amino alcohol as a symmetry-breaking agent, and cupric salt as the inorganic source. Two levels of hierarchical chirality exist for a CuO nanoflower including primary helically arranged “nanoflakes” and secondary helical “subnanopetals” that form “nanopetals”. The nanoflowers exhibited a prominent optical response to circularly polarized light (CPL) at the absorption bands characteristic of CuO

    Synthesis and Characterization of Macroporous Photonic Structure that Consists of Azimuthally Shifted Double-Diamond Silica Frameworks

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    A macroporous silica with azimuthally shifted double-diamond frameworks has been synthesized by the self-assembly of an amphiphilic ABC triblock terpolymer poly­(<i>tert</i>-butyl acrylate)-<i>b</i>-polystyrene-<i>b</i>-poly­(ethylene oxide) and silica source in a mixture of tetrahydrofuran and water. The structure of the macroporous silica consists of a porous system separated by two sets of hollow double-diamond frameworks shifted 0.25<i>c</i> along ⟹001⟩ and adhered to each other crystallographically due to the loss of the mutual support in the unique synthesis, forming a tetragonal structure (space group <i>I</i>4<sub>1</sub>/<i>amd</i>). The unit cell parameter was changed from <i>a</i> = 168 to ∌240 nm with <i>c</i> = √2<i>a</i> by tuning the synthesis condition and the wide edge of the macropore size was ∌100 to ∌140 nm. Electron crystallography was applied to solve the structure. Our studies demonstrate electron crystallography is the only way to solve the complex structure in such length scale. Besides, this structure exhibits structural color that ranged from violet to blue from different directions with the bandgap in the visible wavelength range, which is attributed to the structural feature of the adhered frameworks that have lower symmetry. Calculations demonstrate that this is a new type of photonic structure. A complete gap can be obtained with a minimum dielectric contrast of 4.6, which is inferior to the single diamond but superior to the single gyroid structure. A multilayer core–shell bicontinuous microphase templating route was speculated for the formation of the unique macroporous structure, in which common solvent tetrahydrofuran in hydrophobic shell and selective solvent water in hydrophilic core to enlarge each microphase sizes
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