Characteristics of fluoride adsorption onto aluminium(III) and iron(III) hydroxide flocs

The fluoride adsorption onto the hydroxide flocs of Al(III), Fe(III), or a mixture of the two was studied. The optimum pH was influenced by the flocs’ solubility and surface charge. Although the Al(III) hydroxide flocs had a maximum adsorption capacity at the equilibrium concentration of 8 mg-F/L, the two-stage adsorption process revealed that the mixture of the Al(III) and Fe(III) hydroxide flocs required the smallest adsorbent dose as the concentration changed from 40 to 8 mg-F/L. Thus, the simultaneous dosing of Al(III) and Fe(III) combined with a two-stage adsorption process appears to be an effective option for fluoride removal.     

Colorless polyimides derived from 1S,2S,4R,5R-cyclohexanetetracarboxylic dianhydride,self-orientation behavior during solution casting,and their optoelectronic applications

A novel cycloaliphatic monomer for polyimides (PI), 1S,2S,4R,5R-cyclohexanetetracarboxylic dianhydride (H′-PMDA) is proposed in this work. H′-PMDA shows high polymerizability with various diamines in contrast to its isomer, i.e., conventional hydrogenated pyromellitic dianhydride (H-PMDA) and leads to highly flexible and colorless PI films with very high T_g's. In particular, the combinations with rigid structures of diamines give rise to PIs with significantly decreased coefficients of thermal expansion (CTE) owing to high extents of in-plane chain orientation induced by thermal imidization, whereas the H-PMDA-based counterparts do not. The decreased CTE reflects structural rigidity/linearity of the H′-PMDA-based diimide units as supported by liquid crystallinity observed in the corresponding model compound. Solution casting of a chemically imidized PI derived from H′-PMDA and 2,2′-bis(trifluoromethyl)benzidine (TFMB) results in a lower CTE than that of the thermally imidized counterpart, suggesting the presence of a self-orientation phenomenon during solvent evaporation. The mechanism is proposed in this work. H′-PMDA/TFMB and its copolymer systems can be useful as plastic substrates in image display devices and/or novel coating-type optical compensation films.     

LiF enhanced nucleation of the low temperature microcrystalline silicon prepared by plasma enhanced chemical vapour deposition

A 15-nm lithium fluoride (LiF) thin film evaporated on glass substrate is shown to enhance the nucleation of microcrystalline Si grown by plasma enhanced chemical vapour deposition at the amorphous/microcrystalline boundary conditions. The effect is more pronounced at low substrate temperatures, nucleation density being 10 times higher at ∼ 80 °C. The effect is ascribed to the ionic chemical nature of LiF, the low work function material used in organic electronic devices, and we propose its use for micro patterning crystalline Si regions in otherwise amorphous Si film.     

Colloidal platinum in hydrogen-rich water exhibits radical-scavenging activity and improves blood fluidity

The 'colloidal platinum' stabilized with polyvinylpyrrolidone (Pt/PVP-colloid) was dispersed in hydrogen-rich water (HW; hydrogen concentration, 0.82 ppm; oxidation-reduction potential, -583 mV) or regular water (RW; <0.01 ppm, +218 mV). And we evaluated the antioxidant activity of Pt/PVP-colloid in HW or RW on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and improvement of blood fluidity under 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative stress. When applied with the 0.25-0.5 ppm Pt/PVP-colloid in RW or HW, the level of DPPH radicals decreased to 77.5-59.6% or 16.1-5.6%, in contrast to the level as high as 81.3% for HW alone, respectively, as measured by an electron spin resonance method. The horse blood, which was subjected to AAPH-induced oxidative stress, was incubated for 24 hr with RW or HW, and thereafter required 13.7 sec (100%) or 5.7 sec (42.3%) for passing through the micro-channels in a rheology equipment. When treated with 0.5-1.0 ppm Pt/PVP-colloid in RW or HW, the blood passage time in the micro-channels decreased dose-dependently to 9.7-7.3 sec (71.6-53.8%) or 4.3-1.3 sec (32.8-10.3%), and the rate of micro-channels clogged with erythrocyte aggregates decreased to 23.8-21.0% or 15.8-9.8%, respectively, from 42.8% for no addition of Pt/PVP. By scanning electron microscopy, AAPH-treated erythrocytes lost intact surface morphology on the membrane together with protrusions and without hollows, being indicative of impaired transforming ability, and the rate of erythrocyte agglutination was increased to 46.2%. When treated the horse blood with HW alone significantly decreased the rate of erythrocyte agglutination to 29.6%, whereas 1.0 ppm Pt/PVP-colloid in RW or HW decreased it to 24.1% or 21.1%, respectively. Thus, DPPH-radical-scavenging and erythrocyte-protecting effects of Pt/PVP-colloid in HW were superior to those of Pt/PVP-colloid in RW or Pt/PVP-free HW. The results could be mainly attributed to the enhanced antioxidant activity of Pt/PVP in HW, which may be due to captured-hydrogen on platinum.     

An efficient manufacturing method for I-shaped cross-sectional CFRP beam with arbitrary arrangement of carbon fiber using electro-activated resin molding

Abstract

The I-shaped cross-sectional beam of CFRP (CFRP I-beam) is usually manufactured by the continuous protrusion method. Carbon fibers can only be arranged in the longitudinal direction. The CFRP I-beam with arbitrary arrangement of carbon fiber was manufactured with applying the electro-activated deposition molding method. The carbon fiber fabric was immersed in the deposition solution and energized, epoxy resin precipitated around carbon fiber and impregnated. The resin-impregnated fabric was installed to the mold, and the CFRP I-beam was fabricated. The CFRP I-beam was subjected to three-point bending tests, and the relationship between load-deflection was simulated by finite-element analysis.     

Thermal deformation measurement of the solder joints in electronic packages using electron moiré method

In this paper, electron moiré method is used to measure the thermal deformation of electronic packages. In order to observe the electron moiré fringe, a holographic grid was replicated on the cross section of the BGA type package at 150°C. This grid was fabricated on a glass plate using a moving point holographic system, and was replicated to measured area at high temperature. Under SEM, the holographic grid(specimen grid) and a programmed electron beam scan(master grid) interfere and form electron moiré patterns. The shear strain measurement technique using electron moiré method is described. Using the electron moiré method, the shear strains in the different solder joints were measured and analysed. Some useful results were obtained.     

Particle arrangement and its application

The method by which micrometer-sized particles are arranged, is described. An electrified pattern is drawn on a polished insulating substrate using a SEM with a CAD facility. The substrate is dipped in a suspension of particles. The particles adhere to the substrate and form the pattern corresponding to the electrified pattern by the electrostatic force. The arranged particles are fixed by coating with a fluoride polymer of thin film. The method is applicable to the production of an inflammable gas sensor.     

Electrical conductivity of metastable κ-CeZrO4 phase possessing ordered arrangement of Ce and Zr ions

Electrical conductivity σ_t of metastable κ-CeZrO₄ possessing ordered arrangement of Ce and Zr ions in a manner similar to a pyrochlore-type was measured as a function of temperature and time, and compared with tetragonal metastable t′-(Ce_0.5Zr_0.5)O₂ and t′_meta-(Ce_0.5Zr_0.5)O₂ phases possessing random arrangement of the cations. The κ disk was prepared by reoxidizing a pyrochlore-type precursor in O₂ gas at 873 K. The σ_t as measured for the κ-CeZrO₄ was reproducible as a function of temperatures between 957 and 1190 K. At increasing temperatures above 1233 K, the σ_t decreased gradually with time due to the phase transition: κ→t′, and became consistent with the t′. Although the κ-CeZrO₄ phase is thermodynamically less stable than the t′-(Ce_0.5Zr_0.5)O₂, it was virtually stable up to around 1233 K. It was found from the change in the σ_t due to the phase transition that the σ_t for the metastable κ-CeZrO₄ was an order of magnitude higher than that for the t′ and was similar to that for the t′_meta. It was previously reported that a phase transition, t′_meta→t′, occurred above 1143 K. The phase transition, κ→t′, accompanied by redistribution of the cations appeared to occur at higher temperatures than that for t′_meta→t′ leaving random cation arrangement.