• Journal of the Korean Society of Costume
• /
• v.57 no.9
• /
• pp.67-75
• /
• 2007

The purpose of this research is to conserve of golden decoration(Jikgeumdan) of Chima(skirt) and Jeogori(Korean jacket) of the costumes excavated from Hangju Gi' tomb(17th Century) of Joseon dynasty$(1392{\sim}1910)$ and to focus on the development of conservation skill to prevent flakings of gold leaves in gilt paper strips. Up to the present, in case of golden decorations of costumes excavated from tombs of Joseon dynasty, some of gold leaves in gilt paper strips of costumes were flaked away by deterioration of adhesives in tombs. However, most of gold leaves were flaked away and totally lost by wet cleaning for eliminating contaminants after excavation. In order to prevent flaking, preliminary experiments for re-adhesion of gold leaves have been carried out. Firstly, simulation was performed using gold leaf which was available in the market. Adhesives used in this research were water-soluble adhesives(hide glue(cow, rabbit), glue made from air bladders of sciaenoid fish and Primal AC-3444 of acrylic emulsion) and solvent-soluble adhesives(acrylic adhesive Paraloid B-67 and B-72). Because of difficulty in wetting and spreading of adhesive solutions into the interface between gold leaf and Korean paper, water-soluble adhesives were not proper for adhesion of gold leaf and Korean paper. Solvent-soluble adhesives were easily infiltrated into interface between gold leaf and Korean paper and the adhesive force was also satisfied. From this result, the researchers chose more flexible Paraloid B-72$(Tg\;40^{\circ}C)$ 1% solution than Paraloid B-67$(Tg\;50^{\circ}C)$ for adhesion of gold leaf and Korean paper. Secondly, using Paraloid B-72 1% solution, the estimations of re-adhesions of gold leaves in gilt paper strips of Jeogori were carried out. When Paraloid B-72 1% solution was injected three times into the interface between gold leaf and Korean paper, the re-adhesion was most effective. On the basis of the results in these preliminary experiments, re-adhesions of gold leaves in gilt paper strips of Chima and Jeogori were carried out on condition of three times injections of Paraloid B-72 1% solution before wet cleaning. After wet cleaning, the most of the gold leaves were survived, which was confirmed by both the examination with the naked eye and the microscopic examination.

• Asian-Australasian Journal of Animal Sciences
• /
• v.30 no.11
• /
• pp.1563-1567
• /
• 2017

Objective: The influence of substituting steam-flaked corn (SFC) for dry rolled corn (DRC) on feedlot cattle growth performance and dietary net energy when cattle are allowed either ad libitum or 2-h restricted access to the finishing diet was evaluated. Methods: Treatment effects were tested using 96 crossbred steers ($251{\pm}2kg$) during the initial 56 d of the finishing phase. Cattle were blocked by weight and randomly assigned within blocks to 16 pens (4 pens/treatment). Bunk space was sufficient (41 cm/head) to allow all steers access to the feed bunk at the same time. Treatments consisted of two finishing diets containing (dry matter basis) 77.1% corn grain processed by dry rolling (density = 0.50 kg/L) or steam flaking (density = 0.36 kg/L). Cattle were fed twice daily at 06:00 and 14:00 h, allowing for approximately 5% residual. In the case of restricted feeding, steers were allowed access to feeders for 1 h following each feeding, after which residual feed was withdrawn. Results: There were no treatment interactions on dry matter intake (DMI), average daily gain (ADG), gain efficiency (G:F), or dietary net energy (NE). Restricting feed access time reduced (p<0.01) feed intake, and hence, ADG. Substitution of SFC for DRC increased (p<0.01) ADG, feed efficiency (G:F), and estimated dietary NE, without affecting DMI. Based on tabular net energy of maintenance ($NE_m$) value (2.18 Mcal/kg) for DRC, the estimated $NE_m$ value for SFC using the replacement technique, averaged 2.44 Mcal/kg; an improvement of 10.7%. The ratio of observed-to-expected dietary NE was not affected by feed access time. Conclusion: Substitution of SFC for DRC in finishing diets for feedlot cattle enhanced ADG, gain efficiency, and the NE value of the diet. Although restriction of feed access time depressed DMI and ADG, it did not affect the comparative benefit of steam flaking toward enhancement of ADG, G:F, and dietary NE.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.4
• /
• pp.30-37
• /
• 1997

This thesis is concerned with the study on the characteristics of the tool failure occuring at the beginning of cutting in finish machining of hardened steels such as carbon tool steel and alloy tool steel by a ceramic tool (Al$_{2}$O$_{3}$+TiC) with nose radius. In the machining of hardened carbon steel STC3, the wear mechanism on the flank face of the ceramic tool is abrasion wear. The mode of tool failure is developed into catastropic fracture with flaking. It is thought that the fracture caused by FeO and TiO$_{2}$ results from the oxidation of Fe in the workpice and TiC in the ceramic tool and the deposit of Fe formed on the surface of the ceramic tool. In the machining of hardened alloy steel STD11, the wear mechanism on the flank face of the ceramic tool is that abrasion and adhesion wear exist simultaneously. The mode of tool failure at the beginning of cutting features is DOC notch wear. It is thought that the DOC notch wear caused by FeO and TiO$_{2}$results from the oxidation of Fe and TiC in the workpiece and ceramic tool, respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1575-1578
• /
• 2005

As GA(Galvannealed sheet steel, GA) has good corrosion resistance, weldability and paintability as well as excellent stamping formability it's demand is rapidly increasing for automotive panel. But the layer of the Galvannealed sheet steel is easy to have a coating layer such as powdering and flaking in the press process because it is composed of Fe-Zn alloy. Therefore, the process condition is properly required to form the surface treated sheet steel. The frictional characteristics with dies are changed according to the annealing temperature, $505^{\circ}C,\;515^{\circ}C\;and\;540^{\circ}C$ during the process. To obtain the frictional characteristics of GA sheet steel in this study, on flat friction test is conducted. The friction coefficient is compared with the variation of pressure and velocity, viscosity of lubricant at the various galvannealed temperatures.

• Korean Journal of Organic Agriculture
• /
• v.10 no.1
• /
• pp.35-47
• /
• 2002

In swine production, efficiency of utilization of nutrients is imperative. By embracing advances in processing techniques(i.e., fine grinding, pelleting, steam flaking, roasting, extrusion and expanding) nutrient utilization of feeds turfs have greatly improved. Grinding is by far the most commonly used process with reduction of particle size, Expander, like extruders, are high-temperature and pressure-short-term processor. The purpose of using an expander is to improve pellet quality. Also, expanding of dietary ingredients indicates improvements in growth performance and nutrient digestibility. Because feed cost are easily the greatest economic input into swine production, maximizing nutrient utilization is an area that will continue to receive much attention. Therefore, much attention will continue to be placed on feed processing techniques that will give consistent improvements in animal performance and nutrient digestibility.

• Journal of the Korean Society of Safety
• /
• v.2 no.1
• /
• pp.31-41
• /
• 1987

The surface rolling method which is one of the plastic deformation processes increases the surface roughness with reduction of diameter and hardness. In this study, three NACHI 6000 ZZ bearing were used for surface rolling tool on a mild steel. The following results have been obtained with the mild steel. 1) The load is major factor in getting fine surface roughness of roller fininshing after grinding. The optimal surface roughness of SS40 steel can be obtained at the contact pressure of $210kgf/cm^2$. But, Better surface roughness can not be expected, Due to flaking phenomena at more than 300 kgf/cm of contact pressure. 2) At the contact pressure range of $200kgf/cm^2{\sim}210kgf/cm^2$ for optimal surface roughness, The surface hardness increased to Hv 200~Hv 240 from Hv 125 before surface rolling. 3) Within the diameter variation of $13{\mu}m$ the surface roughness and the surface hardness were increased, but out of variation of $14{\mu}m$. The surface roughness become worse and the surface hardness was increased.

• Corrosion Science and Technology
• /
• v.10 no.1
• /
• pp.1-5
• /
• 2011

The major purpose of the present study is to evaluate the performance of various galvanized (GI) or galvannealed (GA) mild steels and AHSS in stamping applications. Finite Element Analysis (FEA) of selected stamping operations was conducted to estimate the critical pressure boundary conditions that exist in practice. Using this information, laboratory tribotests, e.g. Twist Compression (TCT), Deep Drawing (DDT) and Strip Drawing (SDT) Tests, were developed to evaluate the performance of selected lubricants and die materials/coatings in forming galvanized steels of interest. The sheet materials investigated included mild steels and AHSS (e.g. DP600 GI/GA, DP780 GI/GA, TRIP780 GA and DP980 GI/GA). Experimental results showed that galvanized material resulted in more galling, while galvannealed material showed more powdering and flaking. The surface roughness and chemical composition of galvanized sheet materials affected the severity of galling under the same testing conditions, i.e. lubricants and die materials/coatings. The results of this study helped to determine the critical interface pressure that initiates lubricant failure and galling in stamping selected galvanized sheet materials. Thus, to prevent or postpone the critical interface conditions, the results of this study can be used to select the optimum combination of galvanized sheet, die material, die coating and lubricant for forming structural automotive components.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.39 no.4
• /
• pp.38-44
• /
• 2007

In order to utilize unsorted ONP, which contains leaflets (printed coated papers), to produce pulp mold, optimum conditions for a repulping process were investigated with a laboratory high consistency pulper. It was concluded that medium or high consistency pulping is necessary to accelerate the rate of deflaking of unsorted ONP. Considering flake content, fines content and pulping energy, the optimum conditions for the laboratory Helico pulper were 11% of repulping concentration and 3 min of repulping time. The repulping temperature shall be at least $30^{\circ}C$. Aging of paper slows down the rate of de flaking but in an actual pulp molding process its effect could be negligible.

• JSTS:Journal of Semiconductor Technology and Science
• /
• v.6 no.2
• /
• pp.95-100
• /
• 2006

The GaAs-on-insulator (GOI) wafer fabrication technique has been developed by using ion-cut process, based on hydrogen ion implantation and wafer direct bonding techniques. The hydrogen ion implantation condition for the ion-cut process in GaAs and the associated implantation mechanism have been investigated in this paper. Depth distribution of hydrogen atoms and the corresponding lattice disorder in (100) GaAs wafers produced by 40 keV hydrogen ion implantation were studied by SIMS and RBS/channeling analysis, respectively. In addition, the formation of platelets in the as-implanted GaAs and their microscopic evolution with annealing in the damaged layer was also studied by cross-sectional TEM analysis. The influence of the ion fluence, the implantation temperature and subsequent annealing on blistering and/or flaking was studied, and the optimum conditions for achieving blistering/splitting only after post-implantation annealing were determined. It was found that the new optimum implant temperature window for the GaAs ion-cut lie in $120{\sim}160^{\circ}C$, which is markedly lower than the previously reported window probably due to the inaccuracy in temperature measurement in most of the other implanters.

• Journal of The Geomorphological Association of Korea
• /
• v.25 no.3
• /
• pp.19-42
• /
• 2018

In this study, we surveyed weathering progressing aspect by major elements variation and rock hardness by using XRF analysis, schmidt hammer, and thin section analysis. This observation suggested that the weathering process is likely to develop differently according to microstructural characteristics. R-value on the inside wall are lower than those on the outside. Also, the shadier the environment was, the closer it was to inshore areas, the R-value appeared to be lower. The movement of the elements such as Ca, Na and K shows that feldspar is hydrolyzed and can form salt crystallization like a gypsum or halite when they combine with the elements such as S or Cl. It proved a high CaO, $Na_2O$ and $K_2O$ content on flaking inside wall and rock meal. The exfoliation was mainly observed along the shady backwall and ceiling of tafoni. This helped in predicting the growth of tafoni as well as the direction of its progress.