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The thermal performance of flat plate pulsating heat pipes (PHPs) in compact electronic devices can be improved by adopting asymmetric channels with increased pressure differences and an unbalanced driving force. The objective of this study is to investigate the heat transfer characteristics of flat plate PHPs with various asymmetric ratios and aspect ratios in the channels. The thermal performance and flow pattern of the flat plate PHPs were measured by varying the asymmetric ratio from 1.0 to 4.0, aspect ratio from 2.5 to 5.0, and heat input from 2 to 28 W. The effects of the asymmetric ratio and aspect ratio on the thermal resistance were analyzed with the measured evaporator temperature and flow patterns at various heat inputs. With heat inputs of 6 W and 12 W, the optimum asymmetric ratio and aspect ratio for the flat plate PHPs were determined to be 4.0 and 2.5, respectively. With the heat input of 18 W, the optimum asymmetric ratio and aspect ratio were determined to be 1.5 and 2.5, respectively.

Recently, environmental pollution from microplastics (MPs) has become a significant reason for increasing the number of studies to develop analysis methods. The Nile red staining method (NR-S), which is staining polymer particles with Nile red (NR) dye, has been widely used for the analysis of MPs in environmental samples. However, this method has several limitations, as it is difficult to stain MPs covered with organic matter residues. In this study, we modified the NR-S method into an NR plate method (NR-P), where the plate is coated with NR instead of staining MPs directly. The optimum concentration of NR solution was obtained (1000 mg/L), and the effectiveness of the NR-P method for the analysis of MPs was assessed using different types (polypropylene, polyethylene, polyethylene terephthalate, and polystyrene), sizes (100&ndash, 1000 &micro, m), and shapes (sphere, fiber, film, and flake) of plastic materials. The NR-P method demonstrated improved resolution in the overall types, shapes, and sizes of MPs and was better than the control (without NR plate method) and NR-S method. In particular, the NR-P method can effectively observe MPs covered with organic matter, which was a major limitation of the NR-S method. Finally, MPs in sewage field samples were analyzed by the NR-P method with an accuracy of 78% confirmed by FT-IR. We demonstrated that this method is a convenient and efficient alternative for identifying MPs, even for field samples.

In electric vehicles, air-conditioning (AC) units and electric heaters have been used for dehumidifying and heating the cabin. However, the air heating process in the electric heater causes higher power consumption due to a lower air temperature entering the electric heater from the sensible cooling in the humidifying process. In this study, a heat pump (HP) and a dual-evaporator heat pump (DHP) combined with a heater are proposed as effective dehumidifying and heating units using waste heat recovery from the dehumidifying process. The performances of the AC, HP, and DHP systems were measured and compared by varying the indoor air wet bulb temperature and compressor speed ratio. Generally, the HP and DHP systems showed superior performance to the conventional AC system in the dehumidifying and heating operation. At the indoor air wet bulb temperature of 13 °C, the DHP system showed 53% and 62% higher specific moisture extraction rate and COP, respectively, than the HP system.

A HGSHP (hybrid ground-source heat pump) is proposed to solve the performance degradation of the GSHP (ground-source heat pump) under imbalanced load conditions. The HGSHP is composed of three flow loops: a refrigerant flow loop, a GFL (ground flow loop), and a SFL (supplemental flow loop). In this study, the transient performance characteristics of the HGSHP were measured and analyzed in the cooling mode at various flow loop configurations, including the HGSHP S (HGSHP with the serial configuration) and HGSHP P (HGSHP with the parallel configuration), and GSHP. During the hybrid operation, the HGSHP S showed relatively higher COP (coefficient of performance) than the HGSHP P due to the lower heat accumulation in the ground under the degraded ground thermal condition. In addition, under the steady state condition, the COPs in the HGSHP S and HGSHP P were 15% and 7% higher, respectively, than that in the GSHP.

A multi-heat pump has been widely used to provide cooling and heating in a building. In addition, the demands for a cascade heat pump water heater have been increased due to its higher energy efficiency with high water temperature. In this study, a cascade multi-functional heat pump, which combines a multi-heat pump using R410A for air heating and cooling with a cascade heat pump using R134a for water heating, is considered to provide simultaneous air heating, air cooling, and water heating in a building. The performance of the cascade multi-functional heat pump was measured and analyzed in four operation modes: full-heating hot water, heating-main hot water, full-cooling hot water, and cooling-main hot water. The performance of the cascade multi-functional heat pump in each of the four operation modes was optimized by adjusting control parameters such as the compressor rotation speed and EEV opening and by modifying the refrigerant flow path.

Fluid generated within the sonic or ultrasonic waves are reflected by the wall, while the opposite direction forming a predetermined sound wave to the acoustic standing wave is referred to. In this study, the frequency of 1.0 MHz and 2.0 MHz acoustic standing wave generation module is installed in a continuous particle separation device, the laminar flow of influent, taking into account the hydraulic retention time (HRT) in accordance with changes in particle separation characteristics investigated. Operation of a standing wave in the particle separation device about temperature is increased, but did not significantly affect the formation of standing waves. During operation, the HRT 1 hr frequency 1.0 MHz 2 hr, 4 hr longer as the particle separation efficiency (turbidity) were 64.1%, 70.0%, 74.3% and, 2.0 MHz has 58.0%, respectively, depending on HRT, 61.8%, 70.7% in the respectively. That is, the same frequency, the HRT treatment efficiency is 10% or more, depending on differences in generation and, 1.0 MHz frequency, 2 hr, 2.0 MHz 4 hr at about 70% or more of the processing efficiency can be maintained. Frequency of 1.0 MHz and 2.0 MHz operation at the same time, as a result, HRT 1 hr, 2 hr, 4 hr particle separation efficiency of 63.8%, respectively, 70.6%, 77.6%, rather than the generation of standing waves appear continuous HRT is affecting a lot of particles to separate could know.

We measured chrominance of chrysotile powder using a colorimeter and a luminance meter under different light sources with seven color filters to test feasibility for the real time asbestos detector development. Chrysotile powder was prepared by heating asbestos fabric at 150 °C for 1hr and hydrochloric acid treatment was followed to remove other elements. Refractive index liquid was used as a color changing analyte to observe the change in chrominance of chrysotile. From the measurements, it revealed that a colorimeter was more suitable for the chrysotile detection by the maximum change in chrominance, especially in the short wave length range of blue regions. A luminance meter was not able to separate the difference in chrominance depending on different color and light sources regardless dyeing. It might be due to that reflected light from chrysotile particle was relatively weaker than that from illuminated area. It is our suggestion that the real time monitoring of asbestos in indoor air can be possible using a color sensor, specified to the unique wavelength of dyed chrysotile based on our chrominance data.

A small air-conditioner or chiller for a constant temperature bath normally uses a constant speed compressor. The constant speed compressor is relatively inexpensive, but it uses on/off control for capacity modulation. The on/off control has several disadvantages, specifically energy loss and large temperature fluctuation. Continuous operation with a bypass system can be an alternative to on/off control, for capacity modulation. In this study, a heat pump system having a hot-gas bypass and a liquid bypass was adopted. The performance of the bypass-type heat pump was measured, by varying the bypass valve opening. The differences of the COP between the hot-gas bypass and the liquid bypass, in the cooling and heating operations, were within 2% and 1%, respectively. The liquid bypass showed a wider range of capacity control in the cooling operation but the hot-gas bypass showed a wider range of capacity control in the heating operation.

Due to its irregular structure, the efficiency of the pelletized fibrous filter can be improved if the target substance is line-shaped. Thus, this study was conducted to examine the applications of the pelletized fibrous filter for biological sewage water with line-shaped particles. Towards this end, the pelletized fibrous filter was applied to advanced treatments in which the particles in the sewage water in the supernatant using solid-liquid separation from the final-settling reservoir was filtered with pelletized fibrous filters. To determine the process efficiency of the filter device, a multiparameter water quality analyzer and a data transmission system were established, which showed the efficient process even at a large distance, as well as the good operational status of the filter device. The pilot plant operation results showed that the concentration of TSS in the influent at 20-75 mg/L was reduced to 0.4-10 mg/L in the processed water. The average processing efficiency was 94.9% between 71.4 and 97.9%, and particularly, that of the suspended solids was very high. The results also showed that 27.2% CODMn, 22.5% T-N, and 30.0% T-P were removed.

A simultaneous cooling and heating multi-heat pump can improve thermal comfort and energy efficiency through heat recovery at partial load conditions. The performance of a simultaneous heating and cooling multi-heat pump with four indoor units was measured by varying the compressor speed, EEV opening, and fan speed at full and partial load conditions in five operating modes. In the cooling-only and heating-only modes, the heating and cooling capacities were properly controlled by varying the compressor speed. However, in the cooling-main and heating-main modes under partial load conditions, a large imbalance between the cooling and heating capacities was observed even though the compressor speed was optimized. This capacity imbalance under partial load conditions was optimized by adjusting the EEV openings in the mode change unit and the outdoor unit. In addition, in the entire-heat recovery mode, rating compressor speed ratios were proposed under the full and partial load conditions.

In this research, micro-sized copper bump for multi-layered printed circuit board (PCB) was successfully developed using pulse-reverse electroplating method. The electroplating parameters of current density, pulse-reverse ratio and brightener content were optimized for fabrication of suitable micro-bumps. The pulse-reverse electroplated micro-bumps were characterized using various analytical tools and techniques such as optical microscopy, scanning electron microscopy, atomic force microscopy and hydraulic bulge testing. Optical microscope and scanning electron microscope analysis results indicated good electroplating uniformity in the current density range of 1.4–3.0 A/dm 2 , pulse-reverse ratio of 1:1, and brightener concentration of 600 ppm.

EPP(Expanded Polypropylene) media with a large surface area was developed to treat the first flush of storm water from motorway. A series of studies have been carried out concerning the main mechanism of physical characteristics with the filtration and adsorption of EPP media in EcoTank system in order to evaluate the performance risk for treating trace metals (Cd, Cr, Cu, Pb and Zn) under uncertainty. In view of quantitative and qualitative risk analysis, this study assesses the uncertainty analysis involved in predicting of treating heavy metals from road runoff using an EcoTank system. Results of treatment performance estimation after the treatment of trace metals using an uncertainty analysis were 50.0.% probability (class 3; moderate) for Cd, 52.0% probability (class 4; high) of Cr, 47.1% probability (class 3; moderate) for Cu, 44.4% probability (class 3; moderate) for Pb and 51.2% probability (class 4; high) for Zn, respectively. The performance risk values of all the heavy metals satisfied the acceptable criteria.

With the acceleration of urbanization, impervious surface spreads due to increase of rainfall effluent; consequently, plenty of pollutants occur instantaneously, and severity of a problem caused by being worse of the river and water system is coming to the forefront. Nation Water Quality Inventory reported that 30% of the cause of water quality getting worse is caused by non-point pollutants, and 64% of the cause of polluted water quality of the lake around North Carolina is resulted from non-point pollutants of urban area. This study developed a system that treats and removes pollutants occurring in an impervious area of the urban district by using polymer media. Polymer media, made from polypropylene materials, has float ability and an irregular form. Also this study showed that polymer media has an excellent filtering function of pollutants due to porosity on the surface, and the increase of specific surface area, so that it has an excellent function to remove suspended solids (SS), organic materials and nutritive salts in effluent water on the road side. Treatment efficiency of pollutants in an impervious area of the urban district through application of polymer media to the site is 92.1% and average EMC of suspended solids (SS) is 19.74 mg/L. In addition, treatment efficiency of CODcr is 82.3%, and the efficiency of TN and TP is 50.4% and 73.9%, respectively.

In this study, to effectively control urban non point source pollution, natural and artificial materials which were processed in various ways were charged as a filter media in a real size urban non point source pollution plant(EcoTank) and compared and evaluated the efficiency of filtering solid and organic compounds. The efficiency of filter media was evaluated after collecting dust from urban surface and artificially producing runoffs to evaluate runoff control efficiency of pollutants that caused from pollution in urban streets. To evaluate the efficiency of pollutants runoff control depending on different filter types, EPP(Expanded polypropylene), GAC(Granular activated carbon), Zeolite, Mix-1(EPP in the upper part, GAC in the lower part), Mix-2(GAC in the upper part, EPP in the lower part) was charged to the EcoTank and conducted experiments in an identical condition[6]. As a result of the filter evaluation using real size reactor, EPP was identified as the best filter media for non point source pollution runoff control, and the efficiency was in the following order: EPP > Mix-1 > Mix-2 > GAC > Zeolite.

Joining of NiO–YSZ cermet with 316 stainless steel was carried out using B–Ni3 brazing alloy (4.5 wt% Si, 3.2 wt% B, 0.06 wt% C, 0.02 wt% P, Ni-balance, m.p. 982–1038 °C) to realize reliable sealing of the NiO–YSZ cermet anode/316 stainless steel interconnect structure in a SOFC. In the present research, interfacial (chemical) reactions during brazing at the NiO–YSZ/316 stainless steel interconnect were promoted by either of the two processing methods, (a) addition of an electroless nickel-plate to NiO–YSZ cermet as a coating or (b) deposition of titanium layer onto NiO–YSZ cermet by magnetron plasma sputtering method, with relevant process variables and procedures optimized during either of the pre-processing. Brazing was performed in a cold-wall vacuum furnace at 1080 °C under vacuum level of 10−3 Torr. Post-brazing examination of interfacial morphologies between NiO–YSZ cermet and 316 stainless steel was made using SEM and EDS. The results indicate that B–Ni3 brazing filler alloy was fused fully during brazing and continuous interfacial layer formation significantly depended on the method of pre-coating NiO–YSZ cermet. The inter-diffusion of elements was possibly promoted by titanium-deposition which reduced the diffusion reaction thickness of the interfacial area to less than 16 μm compared to 180 μm for electroless nickel-deposited NiO–YSZ cermet.

This research was conducted to investigate the application of the novel upflow-type filtration device using hydrophobia media made of expanded polypropylene (EPP) from driveways site. The higher level of motorway-derived heavy metal contamination exists in stormwater runoff from a road section and the heavy metal levels were higher than the regulated Korean environmental guideline in lake and river. For Cd, Cr, Cu, Pb and Zn, the influent event mean concentrations (EMCs) during 8 storm periods were 2.75, 37.3, 90.5, 118.5 and 546.5 µg/L, respectively. The novel upflow-type filtration device with main mechanism of filtration and adsorption showed removal (>91%, >93%, >85%, >91% and >80%) of the studied heavy metals (Cd, Cr, Cu, Pb and Zn) and differences of medians of removal efficiencies among heavy metals were not statistically signficant by Kruskal-Wallis test (p>0.05) during 8 storm events. It is found that EPP media is very effective at the removal of the heavy metals, and the magnitude of heavy metal removal in a decreasing order is Cr, Cd, Pb, Cu and Zn.

Since the non point source is unspecified and estimating the degree of occurrence or identifying causing factors are difficult, it is not easy to control. Road runoff is considered a major source of pollution in developed urban sites. Road surfaces accumulate significant quantities of pollutants including nutrients, heavy metals and polycyclic aromatic hydrocarbons(PAHs). Many studies have characterized the constituents of stormwater. These constituents include polycyclic aromatic hydrocarbons(PAHs). Urban non-point source pollutant reducing treatment System is a part of the road runoff treatment which expanded polypropylene(EPP) media with a large surface area to treating the first flush of stormwater from road in field. Urban non-point source pollutant reducing treatment System consist of a container, a total 8.89m2 volume(3.6m(L), 1.3m(W), 1.9m(H)) which is made up of two element; sedimentation chamber of storage tank and filter tank. Under the operating conditions with 0.55h hydraulic retention time(HRT) and a capable of treating a maximum road runoff of 9.5m3/hr, the mean residual total PAHs were 0.699~1.339 µg /L and the percentage mean removal values were 61.4~69.7%, respectively.

Taguchi' design of experiment method and statistical F-test were used to optimize design of tuning forks for use in Qualcomm® mobile station modem (MSM)-3000TM series central processing unit chips of code division multiple access, personal communication system, and global system for mobile communication systems. Design parameters for motional capacitance C1 was further optimized after much trial and error so that as-fabricated resonance frequency values of a tuning fork blank remain almost the same prior to final frequency adjustment plating of the mounted crystals, regardless of packaging pressure change from ambient to designated 6 × 10– 5 Torr. Finite element method modeling was used in conjunction with Taguchi' design of experiment method and, after much trial and error, this enabled selection of essential design parameters to effectively manufacture tuning fork test samples using photolithography with subsequent photoresist spray coating. The tuning fork test samples thus fabricated were characterized and analyzed using Taguchi' method and statistical F-test to evaluate sensitivity of motional capacitance C1 and as-fabricated resonance frequency for various design parameters at ambient to designated packaging pressure of 6 × 10– 5 Torr. Motional capacitance C1 is most sensitive to tine width and tine surface electrode width. Unlike as-fabricated resonance frequency values, motional capacitance values do change with vacuum level of the package. However, tine width asymmetry, electrode thickness and tine tip electrode thickness could be freely adjusted for crystal impedance level without affecting resonance frequency and motional capacitance value. Other design parameters could be adjusted to best suit the manufacturing process.

Pollutants such as heavy metals and PAHs (Polynuclear Aromatic Hydrocarbons) in stormwater runoff are a major problem in urban areas because these pollutants are discharged directly, in most cases without any treatment, into the receiving environments like river and lake. Since many of the pollutants are associated with suspended particulate materials in stormwater, SS (suspended solids) is of acknowledged importance in stormwater runoff treatment by BMPs (best management practices). Filtration, which is commonly used for removing particulate matter in stormwater structural BMPs, depends on various factors (e.g., filter media size, flow rate, bed depth, filter surface properties, etc). Especially, the characteristics of filter media are important factor affecting removal efficiency of pollutants and replacement period of filter media in filtration performance. In this study, EPM (expanded polypropylene media) as a filter media was manufactured at different expansion ratios (i.e., 5, 10, 15 times) and tested in the up-flow filtration for removing pollutants in urban stormwater runoff. The specific surface area of EPM10, EPM15, EPM30, EPM54 was 0.760 m2/g, 0.799 m2/g, 0.812 m2/g, 0.845 m2/g, respectively. The SS removal efficiency (64.1%) by EPM media was higher than that (44.2%) by sand media. In case of EPM10 media, it took 175min of removal rate of filtration system to be approached under 50% and EPM15 media was spent 110min. However, the SS removal efficiency of EPM15 was over 10% higher than that of EPM10. The CODCr removal efficiency of EPM media was also increased with increasing expansion rate. The experimental results in this work show that pollutant removal efficiency by EPM media was increased with increasing expansion ratio but replacement period of media was decreased. EPM media are expected to adsorb non-biological organics like PAHs owing to its hydrophobicity.

With the development of economic status and living standard, eutrophication of lakes has become serious problem. Due to continuous inflow of external nutrients into lakes, phosphorus, a critical nutrient for lake production, has been accumulated in large amount in the sediment. Thus phosphorus rich sediment acts as an internal nutrient source and reduction of phosphorus release from the sediment is very important for restoring eutrophied lakes. Among the various strategies to restore lakes, in-situ capping is known as an attractive and cost-effective method for remediation of contaminated sediments. In this paper, lab-scale batch column test was conducted to evaluate the characteristics of capping materials on reduction of phosphorus release from the sediment. Three different types of capping materials including sand, zeolite, and natural gypsum (CaSO4·2H2O) were used. Each column was filled 7 cm with sediment and covered by 1 cm of sand, zeolite, and natural gypsum, respectively. The change of water quality in supernatant solution was monitored for 10 days in each column. From the results, addition of gypsum showed higher treatment efficiency than sand and zeolite. In case of the capping with gypsum, it was found that the phosphorous release from the sediment could be reduced by around 90% as compared with untreated column. On the contrary, phosphorus reduction efficiencies of sand and zeolite were 60% and 14%, respectively. Moreover, in case of the capping with sand and zeolite, sudden increase of phosphorus concentration was observed with the generation of CH4 gas from sediment. Methanobacterial ebullition is one of the important factors for transporting phosphorus from sediment into water column. It was reported that the addition of gypsum could reduce the progress of methanogensis by supplying sulfate into sediment, which enhances the activity of sulfate-reducing bacteria (SRB) and mineralization rate of organic matter.

Runoff from bridge impermeable surface is discharged directly into the receiving river or sewage pipe. However, generally, a bridge does not have sufficient space to place some treatment system. In this study, therefore, we investigated the down-flow filtration using expended polypropylene media (EPM) to treat runoff from bridge. Experiments were conducted employing down-flow filtration column (dh, 50600mm) to investigate the removal efficiency of pollutants. The EPM5, EPM10, EPM15 and f-EPM10 filters were developed from high molecular material, and were classified by different foaming rates and present of functional material. The experiment using f-EPM10 showed good hydraulic filtration performance without overflow for 1hr. But overflow, in the experiments using EPM5, EPM10 and EPM15, was observed within 1hr. Since f-EPM contains functional material, that can be improved water flow without clogging. The total SS removal efficiency of filtration equipment was rapidly decreased after overflow. In addition, a down-flow experiment, having slope of 15°, to avoid SS deposition at top of the column was carried out. Though SS deposition was found to be similar in two types flow, the flow of down-flow experiment, having slope of 15°, made progress without overflow for 3hr. This is because deposited SS didn’t intercept water inflow.

The individual and combined effects of various alloying elements in aluminum powder compacts were studied in regards to the sintered and heat treated properties. In binary aluminum mixtures, copper formed a persistent liquid phase with aluminum and effectively raised the sintered density and transverse rupture properties, whereas magnesium or zinc formed a transient liquid phase and lowered the density and the properties. In Al-6%Cu base ternary systems, zinc addition improved the sintered properties to some extent but the heat treated properties more significantly. Since the globules of the solidified liquid phase contain a large portion of CuAl 2 phase, which is much harder and more brittle than the matrix, they can act as reinforcing particles in the soft aluminum matrix. The large increase of strength along with the reduction of ductility and also the significant improvement of wear resistance obtained with 6% or more Cu addition are thus attributed to the reinforcing effect of the solidified liquid phase.

Sintered composites of Al-8wt%Cu-10vol%SiCp were deformed by repressing or equal channel angular pressing(ECAP) at room temperature, 500°C and 600°C. Their microstructures and transverse rupture properties were compared. Repressing produced more densification than ECAP but ECAP resulted in much higher strengths than repressing. In both cases, the transverse rupture strengths, after deformation at room temperature and 500°C, are much lower than those deformed at 600°C, despite of only slight differences in density. Fractured SiC particles were observed after the deformation, very frequently at room temperature, less frequently at 500°C and rarely at 600°C. Some interfacial de-bonding between the matrix and SiC particles were also observed particularly in the ECAPed specimens. The higher bend strengths and less SiC fracturing at 600°C are attributable to the presence of an Al-Cu liquid phase during deformation. ECAP at 500°C and 600°C caused recrystallization and produced very fine grain structures. Grain refinement, as well as enhanced bonding between particles due to high shear deformation associated with ECAP, is considered the major reason for the much higher strengths. The employment of copper coated SiC instead of bare SiC particles for preparing the composites was found not beneficial neither for minimizing the particle fracturing nor for improving the properties.

The ultrafine titanium carbonitride particles (TiC0.5N0.5) with 100 nm in mean size was successfully synthesized by nitridation treatment at ordinary temperatures, 1373∼1473 K of the nanostructured half-stoichiometric titanium carbide (TiC0.5) particles, which were produced by the magnesium reduction of gaseous TiCl4+1/4C2Cl4. In addition, the nitrogen stability for the produced titanium carbonitride particles at various temperatures and vacuum conditions was investigated experimentally and compared with values calculated by an ideal solution model.

Powder-metallurgy processed high-speed steels containing up to 5 wt.% of Nb were fabricated by nitrogen gas atomization of elemental powders followed by hot isostatic pressing and hot working. Microstructural changes, particularly the carbide formation during the heat treatment and the resulting mechanical properties were investigated. After the heat treatment, the primary carbides were identified as MC and M6C-types. With Nb addition, the total volume of primary carbides increased from 16 to 23 vol.% and the volume fraction of MC-type carbide in the primary carbides also increased. The chemistry of the MC-type carbide changed from a V-rich to a V–Nb-rich carbide with increasing Nb content. Hardness significantly increased to a maximum of Rockwell C66 with 1 wt.% Nb and then slightly decreased with further Nb additions. Bend strength, on the other hand, gradually decreased with increasing Nb content. Fracture toughness is almost inversely proportional to the hardness and wear and softening resist...

Nanostructured titanium carbonitride (TiC0.5N0.5) powders were synthesized by a Mg-thermal reduction process. The evaporated liquid solution made from TiCl4 + ¼C2Cl4 reacted with liquid magnesium protected with nitrogen gas. The extremely fine titanium carbonitride particles of about 50 nm were successfully produced by the reaction of Ti and C atoms released from chloride reduction with liquid magnesium and nitrogen gas. After the reduction process, the residual phases of MgCl2 and the excess Mg were removed by mechanical vacuum conditions. To obtain the maximized stoichiometry of product, the process optimization with thermodynamic study was performed with various experimental parameters such as reaction temperatures and solution feeding rates.

Carbon supported platinum nanoparticles were synthesized by reducing H 2 PtCl 6 precursor dissolved in water containing carbon powders by a plasma-chemical method. The fast reduction of the precursor was achieved with the help of active hydrogen species generated in the plasma zone contacting the surface of the aqueous solution. The size of the Pt particles supported on the carbon was in the range of 3 to 5 nm with the solution temperature set at 5°C. The performance of the proton exchange membrane fuel cell employing as-prepared Pt/C as the electrocatalyst was comparable to that using commercial Pt/C catalyst.

A hydrophilic nickel nozzle plate for a piezo inkjet printer head with a minimum 5° water contact angle was obtained by (1) primary cathodic electro-cleaning of the detached nickel nozzle plate by applying a cathodic current density of 109.64 A/m2 for 60 s in a thoroughly preelectrolyzed 20 wt% NaOH solution maintained at 97°C, and (2) secondary (post-treatment) cleaning by 1 or 2 min scrubbing of the primary cleaned nickel nozzle plate using a wiper soaked with a newly formulated post-treatment cleaner with inhibitor and surfactant to remove surface oxides and corrosion product films. The successful achievement of the hydrophilic nickel nozzle plate surface is attributed to (1) thorough and careful preelectrolysis of the primary 20 wt% NaOH electrolyte cleaner solution to remove dissolved oxygen and plateable cations, preventing potential aqueous caustic corrosion of the nickel nozzle plate under the more severe corrosive environment at 97°C compared with that of 25°C, and (2) proper formulation of the post-treatment cleaner solution, particularly the selection of the nonionic block copolymer type surfactant which not only assisted in widespread penetration of the cleaner into the NiO scale but also further improved the corrosion prevention performance of the inhibitor. The effect of post-treatment cleaning was experimentally substantiated by measurement of the water contact angle on the post-treatment cleaned nickel nozzle plate surface.