Scratch-resistant hydrophobic and oleophobic coatings prepared by simple PECVD method

A simple and conventional PECVD method was adopted to synthesize scratch-resistant hydrophobic and oleophobic films, by varying the process condition. The film was designed to be 3 layered. The first SiOx layer was coated on the substrate using OMCTS and O₂, followed by O₂ plasma treatment; hydrocarbon-based hydrophobic film was synthesized using HMDS as a second layer; and finally, CFx-based film was coated using C₂F₆. The first and second layers were synthesized using RF power of 13.56 MHz, while MF power of 40 kHz was used for the CFx layer for ion-assisted deposition. The water contact angle was measured to be 110°–115°, and the oil contact angle was 84° for the best obtained sample. The pencil hardness was measured to be 7H for anti-scratch property. XPS was adopted to analyze the chemical structure and showed that highly cross-linked dense structured film was synthesized.     

A Simulation Study on the Collection of Submicron Particles in a Unipolar Charged Fiber

In this study, we developed a simulation method to predict the initial collection efficiency of a unipolar charged fiber and the particle deposition morphology in the electret filter composed of unipolar charged fibers. The particle sizes considered in this study were in the submicron range, and in the simulation method, Brownian motion of particles was also taken into consideration along with electrostatic forces acting on the particles. The simulation results were compared with other investigator's initial collection efficiency data, and it was found that simulation results are in good agreement with the experimental data. Based on this, we analyzed the effect of operating variables on the particle deposition morphology, which in turn affects the collection efficiency and pressure drop of the filter. In view of the simulation results on particle deposition morphology, it is clear that in the case of electret filters, particle deposition tends to take place onto the entire perimeter of fibers relatively uniformly, which may reduce the increase of pressure drop with time or extent of particle deposition compared to the conventional fibrous filter.     

Effects of copper addition on the formation of inclusions and the resistance to pitting corrosion of high performance duplex stainless steels

To elucidate the effects of copper addition on the formation of inclusions and the resistance to pitting corrosion of alloys, potentiodynamic and potentiostatic polarization tests, a SEM-EDS analysis of inclusions, and thermodynamic calculations of the formation of inclusions were conducted. The addition of copper to the base alloy increased the number and area of numerous (Mn, Cr, (Al), (Fe)) oxides and oxy-sulfides due to an increase in the activity of chromium and resulted in decreased pitting resistance. The thermodynamic prediction of the formation of inclusions was in good agreement with the experimental results.     

Mössbauer spectroscopic and chromaticity analysis on colorative mechanism of celadon glaze

The dependence of the color of a celadon glaze on the chemical composition and the electronic state of Fe was investigated by Mössbauer spectroscopic and chromaticity analysis. The amount of Fe₂O₃ was found to be the main factor influencing L* and b* values, whereas the amount of TiO₂ was found to affect all the parameters (L*, a*, b*). The effect of MnO on the color was significant only by interaction terms. The amount of P₂O₅ was found to be the main factor of the b* value. According to the Mössbauer analysis results, as the amount of divalent iron ions increases, the a* and b* values decreased; on the other hand, the L* value increased. As the amount of titanium increased, Fe²⁺ was found to be destabilized relative to Fe³⁺ due to the structural instability of Fe-O-Ti network.     

Improvement in CO2 absorption and reduction of absorbent loss in aqueous NH3/triethanolamine/2-amino-2-methyl-1-propanol blends

Changes in the CO₂ absorption rates and capacities of the absorbent 2-amino-2-methyl-1-propanol (AMP), blended with NH₃ and other additives, were investigated toward performance improvement. The NH₃-blended absorbent removed CO₂ more efficiently than the AMP absorbent alone. However, absorbent loss through NH₃ evaporation was observed under these conditions. A second absorbent, the tertiary amine triethanolamine (TEA), which has a low vapor pressure, was selected and blended with the NH₃/AMP system to reduce NH₃ evaporation. Its effects on NH₃ loss and the absorption rate and capacity of the NH₃/AMP system were investigated, and the optimum blending ratios were determined. In addition, the absorbent blend at the optimum blending ratio was compared to AMP alone and the commercially available absorbent monoethanolamine at the same weight ratio. The thermal stabilities of the absorbents, under conditions used in the CO₂ absorption process, were compared by thermogravimetric analysis.     

Chemical-looping combustion of syngas by means of spray-dried NiO oxygen carrier

Chemical-looping combustion (CLC) of syngas has a potential to generate power economically with achieving the inherent carbon dioxide capture. An oxygen carrier with high reactivity and excellent physical properties would make CLC technology more competitive. In this work, oxygen carrier with 70 wt% NiO was prepared by spray drying technique. The prepared oxygen carrier had excellent physical properties for fluidized-bed application of CLC process. The reactivity of the oxygen carrier in repeated reduction-oxidation was measured by thermogravimetric analyzer with simulated syngas. Oxygen carrier calcined at 1,100 °C showed high oxygen transfer capacity of 14.7 wt%, utilizing 98% of the transferable oxygen. Oxygen transfer capacity and oxygen transfer rate was increased with the increase of reaction temperature, and the highest oxygen transfer rate was observed when about half of the transferable oxygen reacted with syngas. The reduction rate of the syngas (mixture of H₂ and CO) appeared to be approximately the sum of the reaction rate of each fuel gas. The experimental results indicated that the spray-dried NiO oxygen carrier prepared in this work could be a good quality oxygen carrier for the CLC of syngas.     

Enhanced adhesion of osteoblastic cells on polystyrene films by independent control of surface topography and wettability

We independently controlled surface topography and wettability of polystyrene (PS) films by CF₄ and oxygen plasma treatments, respectively, to evaluate the adhesion and proliferation of human fetal osteoblastic (hFOB) cells on the films. Among the CF₄ plasma-treated PS films with the average surface roughness ranging from 0.9 to 70 nm, the highest adhesion of hFOB cells was observed on a PS film with roughness of ~ 11 nm. When this film was additionally treated by oxygen plasma to provide a hydrophilic surface with a contact angle less than 10°, the proliferation of bone-forming cell was further enhanced. Thus, the plasma-based independent modification of PS film into an optimum nanotexture for human osteoblast cells could be appplied to materials used in bone tissue engineering.     

Column redundancy scheme for multiple I/O DRAM using mapping table

A new column redundancy scheme is presented that can minimise the die area overhead by repair circuits and also achieve fast access speed in high density dynamic random access memories (DRAMs) with wide data widths. The proposed scheme has a large redundancy-area-unit (RAU) which operates a flexible column redundancy scheme that consecutively shifts RDQ (redundant I/O) to neighbouring MDQ (main I/O) without any speed penalty. By using the proposed mapping fuse algorithm. The number of fuses required to store the fail bit address can be reduced, and the chip area reduced.     

White organic light-emitting diodes using a quantum dot as a color changing material

White organic light-emitting diodes (WOLEDs) were fabricated by using a blue emitting layer combined with quantum dot (QD) based color converting materials. Orange emitting QD was used as a color converting material and effective color conversion was realized. A white color coordinate of (0.32, 0.41) was obtained with a current efficiency of 8.3 cd/A at 1000 cd/m².     

A data transmission scheme for CDMA wireless networks based onIS-95

Data integration into the existing cellular voice systems is an attractive approach since it can reduce an initial implementation cost of the data network and can provide voice/data integrated services. In this paper, we propose a data transmission scheme for code-division multiple-access (CDMA) cellular voice systems. The CDMA systems under consideration include IS-95 digital cellular systems using the 800-900-MHz band and J-STD-008 personal communications systems using the 1.8-2.0-GHz band. The proposed protocol and control schemes are designed for real systems based on IS-95 rather than conceptual systems and require no modifications to the existing voice mobile stations (MSs). Using computer simulation, the performance of voice and data users is evaluated. As a result, we show that the proposed scheme well meets our design goals, which are that the data transmission scheme should not only provide a good data performance, but also have little effect on the voice performance