• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.7
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• pp.46-52
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• 2006

The effects of surface treatment on the hydrogen storage properties of a $Mg_2Ni$ alloy particle were investigated by the microvoltammetric technique, in which a carbon-filament microelectrode was manipulated to make electrical contact with the particle in a KOH aqueous solution. It was found that the hydrogen storage properties of $Mg_2Ni$ at room temperature were improved by the surface treatment with a nickel plating solution. The sodium salts(sodium phosphate and sodium dihydrogen citrate) contained in the nickel plating solution made the alloy form an amorphous-like state, resulting in an improved hydrogen charge/discharge capacity at room temperature as high as about 150[mAh/g] from the original value of 17[mAh/g]. Potential-step experiment was carried out to determine the apparent chemical diffusion coefficient of hydrogen atom($D_{app}$) in the alloy. Since the alloy particle we used here was a dense, conductive sphere, the spherical diffusion model was employed for data analysis. $D_{app}$ was found to vary the order between $10^{-8}{\sim}10^{-9}[cm^2/s]$ over the course of hydrogenation and dehydrogenation process.

• Journal of Conservation Science
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• v.35 no.3
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• pp.253-258
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• 2019

The gilt bronze statue, Seated Avalokiteshvara with a Thousand Hands, of the Goryeo dynasty, is the only one in Korea of its kind that has undergone a conservation process for the special exhibition entitled GORYEO: The Glory of Korea. For the conservation treatment, first, a component analysis (XRF) was conducted, and a manufacturing technique (CT) was analyzed. The results of the investigation revealed that the statue was alloyed with Cu, Sn, and Pb ternary bronze. Its surface, except for the detached plating layers, was originally plated using the mercury amalgam method. This statue was assembled after separately casting each part of the body, such as the left and right arms and the wrists, including the hands, with objects. In particular, each wrist was cast and fitted with a metal nail to express each object in the hands more precisely. Inside the statue, there were five iron cores: two for the head, one for the left elbow, one for the right flank, and one for the right waist. For the preservative treatment, natural adhesive agents, including vegetable gelatin and glue (20%), were mixed with alcohol to protect the base metal and adhere to the plating layers. Using synthetic resin (CDK 520+SN-sheet) for the damaged parts, the restored parts could be attached and detached to/from the statue. Eventually, the compositional analysis and conservation treatment left the statue in a stable condition and ready for exhibitions and future studies.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.641-647
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• 2005

The partial oxidation of methane is one of important processes for hydrogen production. As a membrane reactor, palladium-silver (Pd-Ag) alloy membrane prepared by electroless plating technique was employed for partial oxidation of methane. The experimental variables were reaction temperature, $O_2/CH_4$ mole ratio, $CH_4$ feed rate, and $N_2$ sweep gas flow rate. The methane conversions increased with the reaction temperatures in the range of 350 to $730^{\circ}C$. The highest methane conversion and CO selectivity were obtained at the condition of $O_2/CH_4$ mole ratio of 0.5 and $730^{\circ}C$ using commercially available nickel/alumina catalyst. The Pd-Ag membrane reactor showed higher methane conversions, 10~40% higher, compared to those in a traditional reactor.

• Journal of the Society of Disaster Information
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• v.13 no.1
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• pp.81-88
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• 2017

In this paper, the behaviour of composite steel-CFRP members is studied experimentally and using FE-analysis. The use of advance composite materials in construction for repair and rehabilitation has become a frequent used method in the last decade. FRP composites have many advantages over the traditional technique of steel bonding for a number of reasons: 1. Composites add little or no additional weight to a building, eliminating the need for costly foundation strengthening. 2. FRP composites are very thin (1.2mm to 1.4mm). So there is no loss of floor space and negligible effect over the architectural aspect. 3. FRP composites do not corrode, this makes it long lasting. However, the method is yet to become a mainstream application due to a number of economical and design related issues. Brittle debonding failure, aging effect on bonding, broad based awareness and proper design guidelines are the main concern for future research works. This paper is focused on the ultimate load carrying capacity of the CFRP-strengthened beams and their effect on the deflection and failures modes by varying the amount of CFRP content.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.2
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• pp.143-149
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• 2000

From the soils of soybean fields in Cotton Branch Station (CBS) and Pine Tree Station (PTS), Arkansas, USA, various single spore isloates of sudden death syndrome (SDS) pathogen were obtained on modified Nash ＆ Snyder's medium (MNSM) with dilution plating technique and transferred to potato dextrose agar (PDA) medium to identify the cultural colony shape. The colony shapes of these isolates resembled F. solani isolate 171 which was white and chalky shaped on MNSM and most of them had unique form of morphology which produced white margin and blue center colony on PDA. Although, some of these isolates had more dark blue or showed slightly different color, all isolates that were selected randomly for green-house inoculation assay produced typical foliar symptoms on leaves of soybean, Hartz 6686. To determine the genetic differences among the isolates, mitochondrial DNA restriction fragment length polymorphism (RFLP) was conducted with fourty isolates from both fields, using mtDNA probes, 2U18 and 4U40, derived from Colletotrichum orbiculare. We obtained distinctive RFLPs in each treatment of restriction enzyme, EcoRI and HaeⅢ. Isolates, 11-2-5 and 14-3-1-1, from CBS and isolates, 104-3-1-2 and 701-1-5-1, from PTS showed different band patterns from 171 in both or in either treatment of restriction enzymes. Even if some of these isolates showed heterogeneous, they were more closer to 171 than PN603. And, also, rest of the thirty-six isolates had exactly same polymorphisms as 171 in each treatment of restriction enzyme. Although, some of the isolates showed the different morphological shape on PDA and slightly different band patterns on RFLPs, all of the isolates selected on MNSM due to their distinctive colony shape from other fungi produced the typical foliar symptoms on soybean leaves in greenhouse inoculation assay. It might be suggested that these isolates were not genetically different from check isolate 171 and they were unique strain of F. solani.

• Korean Journal of Materials Research
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• v.21 no.5
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• pp.288-294
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• 2011

Simultaneous Ni and C codeposition by electrolysis was investigated with the aim of obtaining better corrosion resistivity and surface conductivity of a metallic bipolar plate for application in fuel cells and redox flow batteries. The carbon content in the Ni-C composite plate fell in a range of 9.2~26.2 at.% as the amount of carbon in the Ni Watt bath and the roughness of the composite were increased. The Ni-C composite with more than 21.6 at.% C content did not show uniformly dispersed carbon. It also displayed micro-sized defects such as cracks and crevices, which result in pitting or crevice corrosion. The corrosion resistance of the Ni-C composite in sulfuric acid is similar with that of pure Ni. Electrochemical test results such as passivation were not satisfactory; however, the Ni-C composite still displayed less than $10^{-4}$ $A/cm^2$ passivation current density. Passivation by an anodizing technique could yield better corrosion resistance in the Ni-C composite, approaching that of pure Ni plating. Surface resistivity of pure Ni after passivation was increased by about 8% compared to pure Ni. On the other hand, the surface resistivity of the Ni-C composite with 13 at.% C content was increased by only 1%. It can be confirmed that the metal plate electrodeposited Ni-C composite can be applied as a bipolar plate for fuel cells and redox flow batteries.

• Archives of Craniofacial Surgery
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• v.10 no.1
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• pp.33-36
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• 2009

Purpose: Fractures of the mandibular condylar area are common injuries that account for 29% to 40% of fractures of the facial bones and represent 20% to 62% of all mandibular fractures. Currently 3 main methods are being used in the treatment of mandibular subcondylar fractures: closed reduction; open reduction and internal fixation; Endoscopic reduction and internal fixation. Each method has its proponents and opponent as well as advantages and disadvantages, and indications for each vary among surgeons. There are six approaches of open reduction: submandibular, retromandibular, preaurilcular, postauricular, intraoral, transparotid approach. Among them, transparotid approach has been described for subcondylar exposure with dissection in the direction of facial nerve fibers to expose the bone through the parotid gland. This approach carries the risk of a parotid glandular fistula as well as facial nerve injury but has the advantage of being directly over the fracture site. We report safety and efficacy of surgical treatment using a transparotid approach for direct plating. Methods: A 43-year-old man sustained multiple facial bone fractures by driver traffic accident. Mandibular subcondyle was fractured and dislocated internally. We performed open reduction and internal fixation by transparotid approach. Fractured site was fixed by titanium mini plate & screw. We applicated arch bar for approximately 3 weeks. Results: Follow-up length was about 5months. Scar of surgical incision was indistinct, there was no symptoms and signs of facial nerve and parotid gland injury, and maximal mouth opening was measured 49.5 mm. Conclusion: Transparotid approach has high risks of facial nerve and parotid gland injury, but paradoxically it is the most effective technique in saving facial nerve. Open reduction and internal fixation of mandibular subcondylar fracture by transparotid approach with precise and versed procedure, best outcome can be expected.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.1
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• pp.36-44
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• 2005

A push pull hood system is frequently applied to control contaminants evaporated from an open surface tank in recent years. Efficiency of push pull hood system is affected by various parameters, such as cross draft, vessel shapes, size of tanks surface, liquid temperature, and so on. Among these, velocity of cross draft might be one of the most influencing factor for determining the ventilation efficiency. To take account of the effect of cross draft velocities over 0.38m/s, a flow adjustment of ${\pm}$20% should be considered into the push and +20% into the pull flow system Although there are many studies about the efficiency evaluation of push pull hood system based on CFDs(Computational Fluid Dynamics) and experiments, there have been no reports regarding the influence of velocities and direction of cross-draft on push-pull hood efficiency. This study was conducted to investigate the influence of cross draft direction and velocities on the capture efficiency of the push-pull ventilation system. Smoke visualization method was used along with mock-up of push-pull hood systems to verify the ventilation efficiency by experiments. When the cross-draft blew from the same origins of the push flows, the efficiency of the system was in it's high value, but it was decreased significantly when the cross-draft came from the opposite side of push flows Moreover, the efficiency of the system dramatically decreased when the cross-draft of open surface tank was faster than 0.4m/s.

• Conservation Science in Museum
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• v.16
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• pp.14-31
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• 2015

Sword with round pommel discovered in tomb No.39 in the Jisandong tumuli group (M310) is a large sword with a looped pommel enclosing a sculpted dragon head. The sword was produced using different techniques; gold decoration, plating, openwork carving and hammering by using gold and silver. This sword treated conservation work because it has deformation and damages of handle decoration, missing part of sword, and corrosion. Conservation treatment was that foreign material and corroded metal were removed from the surface, and performed to stabilize and reinforce the weakened metal. During the conservation treatment, the object was examined to understand its materials and production method. The result of research, the dragon head inside the looped, amalgam-plated pommel has surface gold decorations. The pommel has a thin gold plate placed over a bottom plate made of copper, which was hammered to create an embossed design. The silver plate-covered hilt, cylindrical in shape, has an openwork lattice design. The steel blade is single-edged. Finally, the locket of the sheath has an embossed design also created through hammering on a thin gold plate placed over the copper bottom plate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1253-1258
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• 2014

The tribological properties of TiC, TiN and TiC/TiN coatings on steels prepared by the cathodic-arc (CA) ion plating technique were investigated. Experiments were carried out on a tribo-test machine using a Falex journal V block system. The friction and wear characteristics of the coatings were determined by varying the applied load and sliding speed. The TiC, TiN and TiC/TiN coatings markedly increased the tribological characteristics of the surface. As far as a single layer coating was concerned, TiN goes better results than TiC. However, the TiC/TiN multilayer coating performed better than either single layer coating. The major factor in the improved performance of the multilayer coating was the role of TiC in improving the adhesion between the external TiN layer and the substrate steel.