• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2003.05a
• /
• pp.39-43
• /
• 2003

Chloride ions are considered to be the major cause of steel corrosion in concrete structures exposed to seashore environments and also permeation of chloride is controlled by chloride diffusion. Therefore, the study on chloride diffusion of concrete have been done so far by many researchers. It is reported that coating material as surface covering material is effect about deterioration of salt damage and carbonation, therefore these materials are important in durability of concrete structure. In this study, corrosion characteristics of reinforcement concrete according to types of surface covering material were evaluated by water-cement ratio, chloride penetration by age on the corrosion area rate and mass decrement of reinforcement. And it is considered that the result of this study on application of the corrosion characteristics of reinforcements under salt damage environmental will be suggested as fundamental data of control performance of salt damage. It is performed that comparison and examination of control performance of salt damage by the corrosion characteristics under salt damage environmental.

• Proceedings of the KIEE Conference
• /
• 1997.07d
• /
• pp.1308-1310
• /
• 1997

Several methods for electrode fabrication of phosphoric acid fuel cell(PAFC) have been studied. The conventional methods that include a coating method and a rolling method, have disadvantages of a very complicated drying process and a hot pressing process for making a large electrode. In this study, to solve these problems, the mixing method of coating and rolling processes has been developed. In the mixing method, the electrode was coated on the electrode support and, after drying the coated layer, was rolled at room temperature and then sintered at $350^{\circ}C$. The single cell performances of the electrodes fabricated by several methods were examined and the mixing method appeared a good cell performance of 0.65 V, $260\;mA/cm^2$. Also the single cell with an area of $2000\;cm^2$ was manufactured and its performance attained 0.593 V, 300 A.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.6
• /
• pp.618-625
• /
• 2005

This paper has achieved that an optimal design and experiments of heater and cathode of electron gun that serve to embody high current density in CRT display. For the high brightness, high resolution and larger size in CRT display, high current density of electron gun is indispensible. An Impregnation style cathode is used, and must heighten operating temperature of heater to get high current density for this, it is proportional hereupon and power dissipation increases. In this paper, to get low power cathode with high current density, There are produced and tested sample that differ lead type of heater, coating method, the pitch and number of winding of the first and second coiling in the heat emission area for the low power design of high current density cathode heater in this paper.

• Journal of the Korean Society for Heat Treatment
• /
• v.34 no.4
• /
• pp.159-164
• /
• 2021

The Improvement of thermal performance using heat treatment of carbon nanotubes coated on the copper heat sink to take the radiation energy from solar ray for the energy harvesting in earth orbit. Using the additive coating of purified CNT for the increase of specific area and development of thermal conductive capacity, the performance of heat transfer is improved about 0.181 K/W while applying the power of 22 W under temperature of 3.98℃. Coating of purified CNT shows increase of area and volume of thermal layer however it led the partial thermal resistance.

• Corrosion Science and Technology
• /
• v.3 no.1
• /
• pp.20-25
• /
• 2004

In order to clarify the durability of protective coatings for maritime steel structures, various anti-corrosive organic coated steel samples were exposed for twelve years in semitropical marine environment at Miyakojima Island, Okinawa, JAPAN. Samples were various organic coated steel pipes, 4.0 m in length and 150 mm in diameter. While the bare steel pipe entirely corroded in 4.5 mm thickness in four and half years, these organic coated steel pipes exhibited protective appearances after twelve-year-exposure except for the defect in the coatings. Polyethylene (PE) lining pipe exhibited a good protective performance. Urethane painted pipe was also good but some barnacles stuck to its surface. A combination of petrolatum tape and FRP cover showed sufficient corrosion resistance for steel surface. The correlation in results between exposure and laboratory acceleration test was examined. It was found that salt spray test (SST) results corresponded to rusted area of scratched portion and that adhesion change of coating layer corresponded to the rotating immersion test result. Among the on-site measured data, volume resistivity is utilized for the index of corrosion protection performance of organic coating.

• Journal of the Korean Society for Heat Treatment
• /
• v.25 no.6
• /
• pp.283-291
• /
• 2012

In order to increase the anti-oxidation property during the tailor welding blanked hot press forming process for a high strength boron steel sheet, we performed a different coating method on the boron-steel sheet such as 87% Al - 13% Si and Fe - 8.87 Zn dipping plating procedure. However, during laser welding process, the Al-Si coated steel sheet has showed a low tensile strength and about half value of elongation than the original boron-steel sheet. Aluminum and silicon, elements of coating layer were diffused into the boron-steel matrix and have shown a low strength result than non-coated specimen. On the other hand, Zinc-coated boron-steel has expectedly showed a excellent tensile strength and micro-harness value in the welded area like original boron-steel.

• Journal of Electrochemical Science and Technology
• /
• v.11 no.2
• /
• pp.155-164
• /
• 2020

Here we report our preliminary results about nickel phosphide (Ni-P) electroless coating on the surface of cellulose paper (CP) and its feasibility as the anode for lithium (Li) batteries. In particular, CP can act as a flexible skeleton to maintain the mechanical structure, and the Ni-P film can play the roles of both the anode substrate and the active material in Li batteries. Ni-P films with different P contents were plated uniformly and compactly on the microfiber strands of CP. When they were tested as the anode for Li battery, their theoretical capacity per physical area was comparable to or higher than hypothetical pure graphite and P film electrodes having the same thickness. After the large irreversible capacity loss in the first charge/discharge process, the samples showed relatively reversible charge/discharge characteristics. All samples showed no separation of the plating layer and no detectable micro-cracks after cycling. When the charge cut-off voltage was adjusted, their capacity retention could be improved significantly. The electrochemical result was just about the same before and after mechanical bending with respect to the overall shape of voltage curve and capacity.

• Journal of Advanced Marine Engineering and Technology
• /
• v.38 no.10
• /
• pp.1333-1339
• /
• 2014

As the demand for petroleum resources increases, and oilfields on lands and in shallow-sea become exhausted, the areas for oil production are expanding to the deep sea and therefore technologies for flow assurance are coming into the highlight. In low temperature environment such as the deep sea, wax is accumulated and prevents stable oil production. Therefore, the development of flow assurance technologies is required. Wax is precipitated in crystalline form when the oil temperature decreases below the wax appearance temperature; it then accumulates on the inner walls of pipelines causing blockages. In particular, in subsea pipelines, which have a large surface contact area with the surrounding seawater, wax deposition problems are frequent. The internal tubular coating can effectively reduce wax deposition without pausing oil production when the coating is appropriately designed. This study carried out wax deposition tests on a number of internal tubular coatings under single flow conditions. The results were analyzed for the effects that the physical properties of the coatings had on wax deposition.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.24 no.1
• /
• pp.49-55
• /
• 2015

This paper reports solution-processed, high-efficiency organic light-emitting diodes (OLEDs) fabricated by a knife coating method under ambient air conditions. In addition, indium tin oxide (ITO), traditionally used as the anode, was substituted by optimizing the conductivity enhancement treatment of poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films on a polyethylene terephthalate (PET) substrate. The transmittance and sheet resistance of the optimized PEDOT:PSS anode were 83.4% and $27.8{\Omega}/sq$., respectively. The root mean square surface roughness of the PEDOT:PSS anode, measured by atomic force microscopy, was only 2.95 nm. The optimized OLED device showed a maximum current efficiency and maximum luminous density of 5.44 cd/A and $8,356cd/m^2$, respectively. As a result, the OLEDs created using the PEDOT:PSS anode possessed highly comparable characteristics to those created using ITO anodes.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2014.02a
• /
• pp.167.1-167.1
• /
• 2014

We report a facile method to fabricate superhydrophobic, transparent and conductive film using multi-walled carbon nanotubes (MWCNTs) which are coated by polydimethylsiloxane (PDMS). In order to prepare a film, PDMS coated MWCNTs were dispersed in solvents and the solution was drop-casted on substrates. It was demonstrated that the PDMS coating enhanced the dispersion of MWCNTs in diverse solvents such as dimethyl formamide(DMF) and acetone without the use of acids or surfactants, which are the common methods. In the case of DMF solvent, dispersion of MWCNT was improved by 40 % upon PDMS-coating of MWCNT. Enhanced dispersion of MWCNTs made it possible to fabricate transparent and conductive film homogeneously on the substrate and PDMS-coating on MWCNTs also made the surface hydrophobic. We can fabricate a uniform and multifunctional MWCNT film (transparent, conductive, superhydrophobic and flexible) which is applicable on large area without any physical damage and expensive equipment.