Effects of Acetic Acid on the Crystallization Temperature of Sol–Gel-Derived MgO Nano-Powders and Thin Films

The influences of acetic acid addition to Mg-methoxide on the stability of the precursor and the crystallization behavior of sol–gel-derived MgO nano-powders and thin films were investigated using X-ray powder diffraction, transmission electron microscopy, Fourier-transformed infrared spectroscopy, and thermogravimetry. The addition of acetic acid enhanced the stability of the alkoxide against precipitation. Moreover, during postheat treatment of the gel powders treated with acetic acid, a significantly lowered crystallization temperature (250°C) was observed as compared to the untreated counterpart (350°C). The low-temperature crystallization of MgO, induced by the modification of Mg-methoxide with acetic acid, was related to the decomposition of organics at a lower temperature. These results could be explained in terms of the decrease of the O–R bond strength depending on the increase in the alkyl group size. MgO thin films having a high degree of crystallinity were successfully obtained from the Mg-methoxide treated with acetic acid at 300°C. The low-temperature crystallization of sol–gel-derived MgO thin films showed the feasibility for their application as a protective layer in alternative current plasma display panel cells.     

Wetting properties of polystyrene ionomers treated with plasma source ion implantation

The wetting properties of polystyrene‐based ionomers treated with plasma source ion implantation (PSII) were investigated by the measurement of water contact angles. When sulfonated ionomers were aged for a few days, the hydrophobic recovery for the ionomers became much slower than that for the nonionic polymers. However, when the samples were aged over 20 days, the water contact angle of the ionomers converged with that of the nonionic polymer. Thus, it was concluded that the ionic interaction between the ionic groups and the presence of ionic groups together resulted in the slow hydrophobic recovery and that the aging effect was significant for the ionomers. For the methacrylate ionomer of low ion content, on the other hand, it was found that the PSII treatment produced only a small change in hydrophobic recovery behavior. Thus, it was suggested that the low ionic content coupled with the small size of the ionic unit might cause changes only of a very insignificant degree in hydrophobic recovery behavior. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2500–2504, 2002     

Highly Efficient Overall Water Splitting Through Optimization of Preparation and Operation Conditions of Layered Perovskite Photocatalysts

The layered perovskite materials were found to give the high photocatalytic activity in water splitting reaction under UV irradiation, where the electronic structure of perovskite slab constructing the layered structure (the total cation valency) was the most crucial factor to the high photocatalytic activity. Both the excessive cation valency and the layered structure were required for active photocatalysts, while the slab thickness of layered perovskites had an insignificant effect on water-splitting activity. In order to identify key variables that affected photocatalytic activity and to optimize the performance of (110) layered perovskite, La₂Ti₂O₇ was modified by various methods. The optimum amount of loaded nickel had a great effect and the amount depended on the surface area of the perovskite phase. When an alkaline-earth element such as Ba, Sr, and Ca was doped on La₂Ti₂O₇, the photocatalytic activity was enhanced markedly. Introduction of an alkaline hydroxide into the reaction system as an external additive enhanced the activity further showing extremely high quantum yields close to 50%.     

Electrical properties of (Bi3.5La0.5)Ti3O12 thin-films prepared by liquid source misted chemical deposition

The ((Bi_3.5La_0.5)Ti₃O₁₂(BLT) thin-films used in this study were fabricated on a Pt(111)/SiO₂/Si(100) substrate by a Liquid Source Misted Chemical Deposition (LSMCD) technique. X-ray diffraction patterns showed that the BLT films were crystallized and no other phases were observed when annealed above 650 ‡C. Grain size and remnant polarizations increased with increase in the annealing temperature, while leakage current densities decreased. The remnant polarizations (Pr) increased from 2.0 to 4.8 and 19.0 μC/cm2 with increase in the annealing temperature from 650 to 700 and 750 ‡C, respectively. The BLT films annealed at 700 ‡C in O₂ showed a good fatigue resistance of reduced polarization by 10% after 10⁹ switching cycles when 9 V of bipolar voltage was applied at a frequency of 40 kHz.     

An analysis of muscles from ultrasound image using morphological information of fascia and thoracic vertebra

In this paper, we propose a new fully computerized image analysis method for measuring the thickness of muscles from ultrasound image obtained by muscle endurance test using morphological information of fascia and thoracic vertebra. Firstly, we divide the image into lumbar region and thoracolumbar region by the difference of density in image for measuring the thickness of muscles. In lumbar region, we notice that the intensity of fascia is relatively higher than other parts. Thus, we measure the thickness of muscles surrounding the fascia area. In the process, we apply median filter to candidate fascia areas for extracting candidate muscle layers between fascias. Then, the thickness of muscles we measure is that of the third layer. In thoracolumbar region, we apply region expansion method for classifying the region into subcutaneous fat part and part including thoracic vertebra. Then, we apply counting method and evolutionary computation search model to find the measuring location that is in between subcutaneous fat area and thoracic vertebra. In experiment, the proposed method is effective in measuring the thickness of muscles and avoids failures of previous studies. The performance of this approach is sufficiently comparable to that of medical experts.     

Case-based context ontology construction using fuzzy set theory for personalized service in a smart home environment

To provide context-based personalized services utilizing smart appliances in a smart home environment, we propose a framework for PersonAlized Service disCovery Using FuZZY-based CBR and Context Ontology (PASCUZZY). Basically, the PASCUZZY framework is implemented on case-based context ontology. To generate and manage the case instances on the case-based context ontology, we adopt the fuzzy set theory to transpose numerical-type context data sensed from the surrounding environment. The context is transposed to linguistic-type context instances on the context ontology. In addition, to formalize and manage the context and services as multi-attributed data, the context ontology was developed reflecting the structure of cases borrowed from case-based reasoning. Furthermore, we propose adaptation methods to adjust the generic fuzzy membership functions depending on the inhabitants’ context. It is performed by modifying the values of the membership number and/or modifying the numbers of the linguistic terms that are based on the inhabitants’ context to affect the membership numbers. The adapted membership functions return the personalized degree of memberships depending on the specialized context of a specific fuzzy variable. Inevitably, the number of cases on the case-based context ontology will be increased from time to time. We apply Ward’s method not only to reduce the search effort via a hierarchical clustering on the case-based context ontology but also to find the most similar service as a solution to the new context. To verify the superiority of the PASCUZZY framework, we perform two kinds of evaluations. First, we evaluate the effectiveness of the adaptation of the fuzzy membership functions. Second, we verify the effectiveness of the application of a clustering method to the case instances of the case-based context ontology to identify the most similar service. Results of the experiment verified the effectiveness and superiority of the PASCUZZY framework.     

Changes in pore properties of phenol formaldehyde-based carbon with carbonization and oxidation conditions

Porous carbon beads were prepared by carbonizing at 700 and 1000 °C under N₂ (NN-series) or CO₂ atmospheres (CO-series) and a subsequent oxidization with boiling nitric acid solution (13%, v/v) for 3 h (ANN- and ACO-series). BET surface area of both CO- and NN-series samples tends to increase with increasing carbonization temperature, but CO-series samples show higher BET surface areas (700 °C: 610 m²/g, 1000 °C: 780 m²/g) compared with those of NN-series samples (700 °C: 380 m²/g, 1000 °C: 580 m²/g). After acid oxidation, BET surface areas of NN-series samples increased from 580 to 650 m²/g, whereas those of CO-series samples decreased from 780 to 600 m²/g. On subsequent acid oxidation, acidic surface functional groups increased in both CO- and NN-series samples, but the CO-series samples tend to have much more acidic surface functional groups. Adsorption of halogenated methanes, such as tetra-, tri- and dichloromethanes, onto the samples of CO-, NN-, ACO- and ANN-series was thought to be driven initially by the basicity, but the acidic functional groups that could attract adsorbates via dipole-dipole interaction might hinder the adsorption of subsequently incoming adsorbates.     

Adhesion property of novel polyimides with 1‐[3′,5′‐bis(trifluoromethyl)phenyl] pyromellitic dianhydride

Novel polyimides were synthesized from 1‐[3′,5′‐bis(trifluoromethyl)phenyl] pyromellitic dianhydride (6FPPMDA) by a conventional two‐step process: the preparation of poly(amic acid) followed by solution imidization via refluxing in p‐chlorophenol. The diamines used for polyimide synthesis included bis(3‐aminophenyl)‐3,5‐bis(trifluoromethyl)phenyl phosphine oxide, bis(3‐aminophenyl)‐4‐trifluoromethylphenyl phosphine oxide, and bis(3‐aminophenyl)phenyl phosphine oxide. The synthesized polyimides were designed to have a molecular weight of 20,000 g/mol by off‐stoichiometry and were characterized by Fourier transform infrared, NMR, differential scanning calorimetry, and thermogravimetric analysis. In addition, their intrinsic viscosity, solubility, water absorption, and coefficient of thermal expansion (CTE) were also measured. The adhesion properties of the polyimides were evaluated via a T‐peel test with bare and silane/Cr‐coated Cu foils, and the failure surfaces were investigated with scanning electron microscopy. The 6FPPMDA‐based polyimides exhibited high glass‐transition temperatures (280–299°C), good thermal stability (>530°C in air), low water absorption (1.46–2.16 wt %), and fairly low CTEs (32–40 ppm/°C), in addition to good adhesion properties (83–88 g/mm) with silane/Cr‐coated Cu foils. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1801–1809, 2005     

Effectiveness test of alginate‐derived polymeric surfactants

A series of alginate‐derived polymeric surfactants (APSs) with a linear alkyl group (C8, C12, C16) was synthesized by oxidation followed by reductive amination of 2,3‐dialdehydic alginate. The products were characterized by measuring IR spectra, NMR spectra, surface tension and critical micelle concentration (cmc). They were also tested for the solubilization of azobenzene and adsorption of heavy metal. In the case of 40% CHO‐C8 APSs, the lowest interfacial tension value (31.5 m Nm^?1) was obtained at the cmc value of 1.35 g dm^?3. The dissolving capacity of 40% CHO‐C8 APS towards azobenzene was 27 times greater than that of alginate. The overall cobalt (Co²⁺) removal efficiency by adsorption using APSs was high compared with that of sodium alginate at pH 3, 5 and 7. Equilibrium aspects of cobalt adsorption onto 10% CHO‐APSs were studied, and the results show that APSs had high equilibrium capacities for cobalt uptake, 115.5 mgg^?1. © 2002 Society of Chemical Industry     

Selective CO oxidation in the presence of hydrogen over supported Pt catalysts promoted with transition metals

Selective CO oxidation in the presence of excess hydrogen was studied over supported Pt catalysts promoted with various transition metal compounds such as Cr, Mn, Fe, Co, Ni, Cu, Zn, and Zr. CO chemisorption, XRD, TPR, and TPO were conducted to characterize active catalysts. Among them, Pt-Ni/γ-Al₂O₃ showed high CO conversions over wide reaction temperatures. For supported Pt-Ni catalysts, Alumina was superior to TiO₂ and ZrO₂ as a support. The catalytic activity at low temperatures increased with increasing the molar ratio of Ni/Pt. This accompanied the TPR peak shift to lower temperatures. The optimum molar ratio between Ni and Pt was determined to be 5. This Pt-Ni/γ A1₂O₃ showed no decrease in CO conversion and CO₂ selectivity for the selective CO oxidation in the presence of 2 vol% H₂O and 20 vol% CO₂. The bimetallic phase of Pt-Ni seems to give rise to stable activity with high CO₂ selectivity in selective oxidation of CO in H₂-rich stream.