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Fabrication of high sphericity, monodispersed microspheres (100~600 nm) of various oxides (SiO2, TiO2, ZnO, In2O3, SnO2) via sol-gel process and polystyrene (PS) microspheres (200~400 nm) via emulsion polymerization is presented. A high colloidal stability suspension was obtained by adjusting the zeta potential of such spheres and pH of the colloid. The 3-D photonic crystal (PhC) templates of opaline structure on ITO-coated glasses and silicon wafers were easily formed under electrophoretic self-assembly (EPSA) of microspheres under the influence of exerting electrical forces. Different setups of counter-electrode were attempted to establish an electrical field. The lattice constant of an ordered opal structure by EPSA can also be tuned by the electrical field gradient. Interestingly various self-assembled 3-D structures of silica microspheres in either symmetrical curvilinear profile or triangular ridges can be produced through EPSA route using specific counter-electrode setups. The measured optic properties of such 3-D PhC templates manifest photonic bandgap (PBG) based on planar-wave expansion (PWE) simulation to verify the existence of real PBG in PhC samples with tunable nanostructures. The PS PhC templates are currently used to easily transform into inverse opal structure (IOS) by infiltrating sol of other oxides with high dielectric constant (e.g. ZnO or TiO2) and filled with metallic nanoparticles (Ni or Cu) by electrochemical deposition or chemical bath deposition (CBD).

This study sought to determine the association between twinkling artifacts on color Doppler ultrasound and different types of guidewires.Twenty-two commonly used guidewires were classified into three groups according to decreasing diameter (Group 1, 0.035"; Group 2, 0.018"; and Group 3, 0.014") and testedThe percentages (tips/shafts) of twinkling artifacts were 100%/100% for Group 1; 0%/33.3% for Group 2; and 18.8%/31% for Group 3. The mean scores (tips/shafts) were 2.3/2.7 for Group 1; 0/0.3 for Group 2; and 0.3/0.4 for Group 3. Among them, both two guidewires with strong twinkling artifacts (score = 3) exhibited extensive rough surfaces on microscopic pictures.The twinkling artifacts were more likely to present in guidewires with larger diameters (from 0.014" to 0.035") in our study settings. The surface roughness may be the contribution to the twinkling artifact. Internal heterogeneities, such as types of material, types of coating, tip loading, and spring coil length, do not show influence on the twinkling artifact.

Vitrification was used to convert hazardous metal-bearing fly ash from municipal solid waste (MSW) incineration into useful products in this work. In addition to volume/mass reduction, some parameters such as basicity, metal leachability, density, porosity, water absorption, and compressive strength of the slags and ingots vitrified from fly ash and fly ash/additive (bottom ash and cullet) mixtures (at 1450°C for 1.5 h) were investigated. The more the bottom ash or cullet added to the fly ash, the lower the specimen basicity, leading to a more amorphous glassy matrix. Amorphous glassy slags were obtained when the specimen basicity was around 0.24-1.24. All slags were in compliance with the limits of TCLP (Toxicity Characteristic Leaching Procedure) in Taiwan, United States, and Japan. The vitrification process reduced the leaching amount and ratio of Cr and Pb, significantly lowered the leaching ratio of Cd, but raised the leaching ratios of Zn and Cu. The slag metal leachability (particularly for Cu) was mainly influenced by the metal content in slags, not the slag (crystal or glassy) structure or basicity. After vitrification, an over 50% specimen volume reduction was achieved and most of the specimen mass moved to the slag phase. The ingots, mainly consisting of Fe, also met Taiwan and U.S. TCLP requirements and were suitable for a higher purity metal recovery. The slags and ingots were approximately 2- and 6-fold as dense as the specimens before vitrification, respectively. The slags were found to have very small porosities, low water absorptions, and high compressive strengths (>550 kg/cm 2 ), so they may be considered as candidate materials for waterproof and construction.

Purpose: This study sought to determine the association between twinkling artifacts on color Doppler ultrasound and different types of guidewires. Materials and Methods: Twenty-two commonly used guidewires were classified into three groups according to decreasing diameter (Group 1, 0.035”; Group 2, 0.018”; and Group 3, 0.014”) and tested in vitro. Severity of twinkling was visually graded into four categories (0–3, from weak to strong). Results: The percentages (tips/shafts) of twinkling artifacts were 100%/100% for Group 1; 0%/33.3% for Group 2; and 18.8%/31% for Group 3. The mean scores (tips/shafts) were 2.3/2.7 for Group 1; 0/0.3 for Group 2; and 0.3/0.4 for Group 3. Among them, both two guidewires with strong twinkling artifacts (score = 3) exhibited extensive rough surfaces on microscopic pictures. Conclusion: The twinkling artifacts were more likely to present in guidewires with larger diameters (from 0.014” to 0.035”) in our study settings. The surface roughness may be the contribution to the twinkling artifact. Internal heterogeneities, such as types of material, types of coating, tip loading, and spring coil length, do not show influence on the twinkling artifact.

A vertical electrophoretic deposition method was employed to fabricate polystyrene (PS) colloidal crystals with negligible defects and considerable surface uniformity. Subsequently, the interstitial voids within the colloidal crystals were electroplated with Ni, followed by selective removal of the PS microspheres. With careful adjustment in the processing parameters, we were able to obtain Ni inverse opals at predetermined thickness in relatively short time. The inverse opals revealed superb structural stability and surface uniformity. Because the electrophoresis and electrodeposition were both carried out in a solution state, this fabrication scheme enables facile construction of inverse opals on conductive substrates over conventional approaches.

We fabricate cylindrical colloidal crystals (CCCs) via electrophoretic depositions of polystyrene microspheres on a carbon fiber in a concentric arrangement. Images from optical and scanning electron microscope indicate that the CCCs of 460 nm microspheres reveal a semicrystalline structure in close-packed lattice, while the CCCs of 660 exhibit an amorphous arrangement. In optical reflectance spectra, both CCCs demonstrate a dispersive photonic bandgap as compared to that from planar counterparts. The curved contour for the CCCs renders incident light interacting with reflecting planes at slightly different angles, leading to a notable reduction in the reflectance intensity and minor relocation of photonic bandgap contingent on their crystallinity.

We demonstrate a facile fabrication scheme to construct large-area ZnO inverse opals on an indium-tin-oxide substrate with significantly reduced defects and improved stoichiometry. The fabrication steps involve the preparation of colloidal template via vertical electrophoresis of polystyrene (PS) microspheres in 720 nm radius, followed by galvanostatic electrodeposition of ZnO in the interstitial voids among the PS microspheres. Subsequently, the sample undergoes a heat-treatment in air at 500 C for different time to remove the colloidal template, leaving an integral ZnO skeleton with thickness adjusted by the electrodeposition time. Since the colloidal template is deliberately designed with desirable thickness and considerable uniformity, the electroplating of ZnO can be achieved in a reduced ethanol/water ratio that allows faster growth rate and improved ZnO structure. Scanning electron microscope images demonstrate negligible microstructural defects for the ZnO inverse opals. X-ray diffraction reveals a wurtzite hexagonal lattice with (002) preferred orientation. In addition, both X-ray photoelectron spectroscopy and photoluminescence spectra suggest improved crystallinity and stoichiometry with increasing heat-treatment time. VC 2011 The Electrochemical Society. [DOI: 10.1149/1.3552604] All rights reserved.

We employed an electrophoretic deposition technique to prepare cylindrical colloidal crystals (CCCs) from polystyrene (PS) microspheres of 460 and 660 nm diameters using a carbon fiber (CF) with 7 μm diameter as the substrate. Measurements on the CCC diameter demonstrated growth rates that slowed down as time progressed. Scanning electron microscope images confirmed that the CCCs of 460 nm microspheres formed a face-centered cubic close-packed lattice, whereas an amorphous structure appeared for the CCCs of 660 nm. Subsequently, both CCCs underwent a potentiostatic electroplating to deposit Ni into the interstitial voids among the PS microspheres. After chemical removal of the PS microspheres, we fabricated cylindrical inverse opals (CIOs) in various diameters. As expected, better crystallinity was found on the CIOs of 460 nm microspheres as opposed to the 660 nm ones. The electrical resistivity for both CIOs exhibited a substantial reduction over that of the CF. Our CCCs and CIOs revealed considerable structure stability with excellent surface uniformity. The fabrication scheme enables rapid preparations of CCCs and CIOs in desirable lengths and diameters.

A vertical electrophoretic deposition technique was employed to prepare polystyrene (PS) colloidal crystals with negligible crystallographic defects. The colloidal crystals were plated with Ni, followed by selective removal of PS microspheres to fabricate inverse opals. With adjustments in relevant processing parameters, we were able to obtain inverse opals in multiple layers with excellent surface uniformities. The inverse opals were used as the electrode material for water electrolysis. Results from current-potential polarizations in 1 M KOH aqueous solution indicated that the catalytic abilities for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) increased with the layers of inverse opals. Estimation of the effective current densities determined that the entire area of the inverse opals was available for electrochemical reactions. In galvanostatic measurements for both OER and HER, the inverse opals demonstrated stable voltage profiles without notable degradations for 120 h. Compared with a planar Ni plate, the inverse opals exhibited a significantly reduced overpotential for the water electrolysis.

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