• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.378-380
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• 2009

$MgF_2$ is a current material for the optical applications in the UV and deep UV range. Process variables for manufacturing the $MgF_2$ thin film were established in order to clarify optimum conditions for growth of the thin film depending upon process conditions, and then by changing a number of vapor deposition conditions and substrate temperature, Annealing conditions variously, structural and Optical characteristics were measured. Thereby, optimum process variables were derived. Nevertheless, modern applications still require improvement of the optical and structural quality of the deposited layers. In the present work, the composition and microstructure of $MgF_2$ single layers grown on slide glass substrate by Electro beam Evaporator(KV-660) processes, were analyzed and compared. The surface Substrate temperature having an effect on the quality of the thin film was changed from $200[^{\circ}C]$ to $350[^{\circ}C]$ at intervals of $50[^{\circ}C]$. and annealing temperature an effect on the thin film was changed from $200[^{\circ}C]$ to $400[^{\circ}C]$ at intervals of $50[^{\circ}C]$. Physical properties of the thin film were investigated at various fabrication conditions substrate temperature, annealing and temperature, annealing time by XRD, FE-SEM.

• Korean Journal of Food Science and Technology
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• v.17 no.4
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• pp.311-318
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• 1985

This review was intended to develop the sterilization method of spices by gamma irradiation and the results are summarized as follows. Microbial load of spices was different according to the kind of spices and the number was ranged from $10^{2}$-$10^{5}/g$ to $10^{7}$-$10^{8}/g$, gamma irradiation up to 4-10 kGy could decreased or sterilized to the microorganism of spices. In physicochemical properties of spices such as chemical components,essential oil and flavor, irradiated group with optimum dose was almost similar to the nonirradiated one, while fumigant treated group was remarkably deteriorated in the properties of spices compared with control, and free radicals produced by irradiation was disappeared during a few days storage. Irradiated spices should be an aptitude for good quality the storeability of processing food. Optimum dose irradiation below less than that proposed by FAO/IAEA/WHO Joint Committee and FDA was remarkably effect on the sterilization of spices and superior in wholesomeness and economic feasibiity compared with traditional methods. Irradiation might be an alternative to traditional sterilization methods of spices by fumigants such as ethylene oxide and ethylene dibromide because their treatments have been banned in U.S.A and other countries since 1982.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.373-376
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• 2005

In recent years, there has been a growing need fur productivity improvement of ACS wire (Aluminum clad Steel wire) In optical communication market. So, it is necessary to improve the production speed and following quality of ACS wire to reduce the unit cost of the products. In this study, the pre-heating temperature and cladding speed is chosen as the factors can influence the mechanical and metallurgical properties during cladding, and the changing behavior of mechanical property and microstructure by controlling above two factors are investigated. And the bearing length and approach angle in cladding die are selected as the important elements for designing optimum die enabling high speed cladding. So we carried out FE(Finite Element) analysis using the above two elements as variables. This paper aims to understand the change of mechanical properties and microstructure according to the change of each factor during cladding and suggest the optimized cladding condition to get the best quality of OPGW. And also we would like to introduce the optimum die structure that enables high-speed cladding.

• Journal of Welding and Joining
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• v.19 no.1
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• pp.65-74
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• 2001

A study on the corrosion behavior in case of As-welded and PWHT temperature 55$0^{\circ}C$ of welding part of RE36 steel for marine structure was investigated with parameters such as micro-Vickers hardness, corrosion potential measurement of weld metal(WM), base metal(BM) and heat affected zone(HAZ), both Al anode generating current and Al anode weight loss quantity under sacrificial anode cathodic protection conditions. And also we carried out slow strain rate test(SSRT) in order to research both limiting cathodic polarization potential for hydrogen embrittlement and optimum cathodic protection potential as well as mechanical properties by post-weld heat treatment(PWHT) effect. Hardness of HAZ was the highest among three parts(WM, BM and HAZ) and the highest galvanic corrosion susceptibility was HAZ. And the optimum cathodic polarization potential showing the best mechanical properties by SSRT method was from -770mV to -875mV(SCE). In analysis of SEM fractography, applied cathodic potential from -770mV to -875mV(SCE) it appeared dimple pattern with ductile fracture while it showed transgranular pattern (Q. C : quasicleavage) under -900mV(SCE). However it is suggested that limiting cathodic polarization potential indicating hydrogen embrittlement was under -900mV(SCE).

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.6
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• pp.16-25
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• 2014

This study was investigated in optimum condition of pulping of ramie and the mechanical properties of non-woven fabric for the performance of ramie/cotton panty liner. The result of pulping condition on ramie was most suitable for type I (mixed NaOH with $Na_2CO_3$ in 30%:70%). The sample (I) was showed yield value of 68.2% and the best fibrillation and lignin removal rate. The non-woven fabrics of ramie/cotton were made in range of ramie content of 0, 15 and 30%. As ramie content increased, so were increased in air permeability, compressive strength and compression recovery rate. But surface roughness and compressional energy were decreased. Therefore, the non-woven fabrics of ramie/cotton are very suitable in hygienic goods for female panty liner. The ramie panty liner showed a little decrease in absorption and strength, as increasing the amount of ramie. But the performance of ramie panty liner was appeared beyond standard values used by usual panty liner.

• Journal of the Korean institute of surface engineering
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• v.30 no.4
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• pp.285-297
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• 1997

Finned segment, with which are lined inner wall of the turbine combustors, are subject to severe degradation when they are exposed to a hostile environmment at elevated temperature. To protect the finned segment from this environment and to maintain good mechanical properties of components at high temperature, they are preferred to be coated. The most governing factor for the durability of coatings used in the high temperature is the microstructure of coatings; these are splat from, distibution of microcacks, size and distribution of pores, thickness of coating layer, adhesion between coating layer, and oxidation of band coating. In this study, based on the evaluation of the imported finned segment, new finned segment segment was manufactured with optimum plasma spraying parameters, and their properties were examined. Using $ZrO_2(8wt$Y_2O_3)$,/TEX> powder for ceramic coating and 67Ni-22Cr-10Al-0.5Y mixing powder for bond coating, thickness of ceramic and bond coating layer were varied in order to find optimum condition, the results showed that B2T4(bond coating : 100~250$\mu\textrm{m}$, ceramic coating : 250~300$\mu\textrm{m}$) was the best among the specimens tested. Compared to the imported finned segment, B2T4 has better bond strength, hardness, and isothermal and cyclic oxidation resistance.

• 보존과학연구
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• s.15
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• pp.21-32
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• 1994

Optimum conditions for benzene synthesis and liquid scintillation counting have been studied for the determination of radiocarbon age. In benzene synthesis the carbon dioxide converted to benzene with high efficiency of 91%. Yields of each step with 10L of carbon dioxide were $CO_2$ $\rightarrow$$C_2H_2$(94%), $C_2H_2$$\rightarrow$$C_6H_6$(96%) and$CO_2$$\rightarrow$$C_6H_6$(91%), respectively. Benzene synthesized from oxalate was measured with purity of 95% by GC /MS. $\delta^13$(C$^13$C/$^12$C) of oxalate was measured to $-24.7\{textperthousand}$ by massspectrometer. For liquid scintillation counting of benzene sample low background and highest FOM were measured in 0.5 ml cocktail and 3 ml standard solution with the range of 15.4∼74.9 KeV window setting. Oxalate and background samples weremeasured to $28.7\pm0.12$cpm and $3.92\pm0.04$ cpm in 15.4∼74.9 KeV

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.824-829
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• 2002

Optimum conditions for gelatin extraction from chicken feet subjected to liming and neutralization processes were determined in terms of the effects of extraction temperature and time on the yield and physicochemical properties of gelatin using response surface methodology. The yield of gelatin increased with the increased extraction temperature and time, whereas viscosity and hardness only increased up to certain levels of temperature and time, and decreased thereafter. Based on the physicochemical properties, the optimum conditions for gelatin extraction were determined as $73^{\circ}C$ for 3 h 40 min.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.12
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• pp.1039-1043
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• 2007

In this paper, in order to develop low temperature sintering ceramics for multilayer piezoelectric actuator application, PMN-PZN-PZT ceramics were fabricated using $LiCO_3,\;Bi_2O_3$ and CuO as sintering aids. And also, their piezoelectric and dielectric properties were investigated according to the milling time. All the specimens sintered at $930\;^{\circ}C$ showed tetragonal phases without secondary phases. With increasing milling time, piezoelectric and dielectric characteristic of specimens increased up to 60 hours milling time and then decreased due to the agglomeration of fine particle. Accordingly, it seems that 60 hour is optimum milling condition. At the sintering temperature of $930\;^{\circ}C$ and milling time of 60 hour, density, dielectric constant(${\varepsilon}_r$), electromechanical coupling factor (kp), mechanical quality factor (Qm), piezoelectric d constant showed the optimum value of $7.95\;g/m^3$, 1382, 0.546, 1749, 330 pC/N, respectively for multilayer piezoelectric actuator application.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.5
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• pp.687-696
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• 2010

This study focused on microwave irradiation of dough, raising its temperature to monitor potential variations of dough properties and bread quality, and examined the optimum mixture ratio towards streamlining the bread-making process. According to comparison and analysis on dough properties and bread quality depending on mixture materials, it was found that Salt 2 had the highest dough temperature of all, and Salt 1 had the highest fermentation rate and specific volume but the lowest hardness (i.e. highest softness). Results of sensory evaluation, were that Salt 1.5 scored highest points in sweet taste, aftertaste, and overall acceptance, but there were significant differences among bread samples. Likewise, it was found that Fat 6 had the highest dough temperature, fermentation rate and specific volume of all. Texture analysis, showed that Fat 0 had the highest hardness of all. According to sensory characteristics, Fat 3 scored the highest points in overall acceptance. Based on these results, the optimum mixture ratio of salt and fat for microwave-irradiated bread was found to be 1.5% salt and 3% fat.