• Corrosion Science and Technology
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• v.14 no.2
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• pp.93-98
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• 2015

Recently, Stainless steels have been increasingly selected as the fitting or the valve materials of water pipes as the human health issue is getting higher and higher. Therefore, the connectors attached at pipes to deliver water are exposed to more severe environments than the pipes because crevice or galvanic corrosion is apt to occur at the fittings or the valves. Effects of the solid solution annealing, cooling rate after this heat treatment, and passivation on the corrosion properties of the shell mold casted SSC13 (STS304 alloy equivalent) were studied. The heating and quenching treatment more or less reduced hardness but effectively improved corrosion resistance. It was explained by the reduction of delta ferrite contents. Independent of heat treatment, the chemical passivation treatment also lowered corrosion rate but the improvement of corrosion resistance depended on temperature and time for passivation treatment indicating that the optimum conditions for passivation treatment were the bath temperature of $34^{\circ}C$ and operating time of 10 minutes. Therefore it is suggested that the corrosion resistance of SSC13 can be effectively improved with the heat treatment, where SSC13 is heated for 10 minutes at $1120^{\circ}C$ and quenched and passivation treatment, where SSC13 is passivated for at least 10 seconds at $34^{\circ}C$ nitric acid solution.

• Journal of the Korean Society of Food Culture
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• v.12 no.2
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• pp.195-200
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• 1997

The purposes of this study were to investigate the Maillard reactions of some oligosaccharides with lysine and the antioxidative effects of the ethanol extracts from their reaction mixtures on the soybean oil. The Maillard reactions were carried out of 2% oligosaccharides such as palatinose (PN), fructooligosaccharide (FO), isomaltooligosaccharide (IMO) with 2% lysine (L) for 24 hours heating at 60, 80, $100^{\circ}C$. The color intensity of Maillard reaction mixtures were determined by UV-VIS spectrophotometer upon reaction time and temperature. And the antioxidative effects on the soybean oil of each ethanol extract from Maillard reaction mixture of each oligosaccharide were measured by peroxide value (POV). POV's of soybean oil including reaction extracts were determined regularly every 2 days during 20 days storaged at $60{\pm}1^{\circ}C$. The results were obtained as follows: 1. The color intensity of the Maillard reaction mixtures were raised highly as the browning temperature and time increased. The color intensity of PN L browning mixture was the highest. The order of high color intensity at $100^{\circ}C$ was PN L>FO L>Glu L>IMO L. 2. Comparing the antioxidative effect of Maillard reaction product (at $100^{\circ}C$, for 12 hours) of each oligosaccharide to that of BHT and TBHQ, the order of high antioxidative effect was TBHQ>IMO L>BHT>Glu L>PN L>FO L. 3. From these results, it was known that PN L shown as high brown color intensity was appeared low antioxidative effect, while IMO L shown as low brown color intensity was appeared high antioxidative effect. So, it was recognized that there was no relation between brown color intensity and antioxidative effect.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.148-154
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• 2022

As the 4th industrial age approaches, the demand for semiconductors is increasing enough to be used in all electronic devices. At the same time, semiconductor technology is also developing day by day, leading to ultraprecision and low power consumption. Semiconductors that keep getting smaller generate heat because the energy density increases, and the generated heat changes the shape of the semiconductor package, so it is important to manage. The temperature change is not only self-heating of the semiconductor package, but also heat generated by external damage. If the package is deformed, it is necessary to manage it because functional problems and performance degradation such as damage occur. The package burn in test in the post-process of semiconductor production is a process that tests the durability and function of the package in a high-temperature environment, and heat dissipation performance can be evaluated. In this paper, we intend to review a new material formulation that can improve the performance of the adapter, which is one of the parts of the test socket used in the burn-in test. It was confirmed what characteristics the basic base showed when polyamide, a high-molecular material, and alumina, which had high thermal conductivity, were mixed for each magnification. In this study, functional evaluation was also carried out by injecting an adapter, a part of the test socket, at the same time as the specimen was manufactured. Verification of stiffness such as tensile strength and flexural strength by mixing ratio, performance evaluation such as thermal conductivity, and manufacturing of a dummy device also confirmed warpage. As a result, it was confirmed that the thermal stability was excellent. Through this study, it is thought that it can be used as basic data for the development of materials for burn-in sockets in the future.

• Journal of Ginseng Research
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• v.45 no.1
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• pp.163-175
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• 2021

Background: Ginsenosides, which have strong biological activities, can be divided into polar or less-polar ginsenosides. Methods: This study evaluated the phytochemical diversity of the saponins in Panax ginseng (PG) root, American ginseng (AG) root, and Panax notoginseng (NG) root; the stem-leaves from Panax ginseng (SPG) root, American ginseng (SAG) root, and Panax notoginseng (SNG) root as well as the saponins obtained following heating and acidification [transformed Panax ginseng (TPG), transformed American ginseng (TAG), transformed Panax notoginseng (TNG), transformed stem-leaves from Panax ginseng (TSPG), transformed stem-leaves from American ginseng (TSAG), and transformed stem-leaves from Panax notoginseng (TSNG)]. The diversity was determined through the simultaneous quantification of the 16 major ginsenosides. Results: The content of ginsenosides in NG was found to be higher than those in AG and PG, and the content in SPG was greater than those in SNG and SAG. After transformation, the contents of polar ginsenosides in the raw saponins decreased, and contents of less-polar compounds increased. TNG had the highest levels of ginsenosides, which is consistent with the transformation of ginseng root. The contents of saponins in the stem-leaves were higher than those in the roots. The transformation rate of SNG was higher than those of the other samples, and the loss ratios of total ginsenosides from NG (6%) and SNG (4%) were the lowest among the tested materials. In addition to the conversion temperature, time, and pH, the crude protein content also affects the conversion to rare saponins. The proteins in Panax notoginseng allowed the highest conversion rate. Conclusion: Thus, the industrial preparation of less-polar ginsenosides from SNG is more efficient and cheaper.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.655-660
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• 2015

This study investigated the effects of freezing storage temperature and thawing time on the separation of leg meat of the red snow crab Chionoecetes japonicus. Crabs were stored at -20, -30, -40, or -50°C for 2 days and thawed for either 5, 10, 20, 30, or 40 seconds. While thawing, there were no significant differences in pH or acidity among the experimental groups, while the volatile basic nitrogen content increased continuously. The redness of samples stored at -20°C was higher than that of the other groups. The overall acceptance of samples stored at -20°C was also the best. These results demonstrate that no-heating methods may be useful for separating red snow crab leg meat.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.3
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• pp.285-289
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• 2013

The coastal area of Republic of Korea is very clean compared to other countries. In this reason, west coastal area of our country is a good place for breeding up a fish such as shrimp. In winter season, the heating system is required for preventing shrimp death caused by freezing in the farm. The heater in the heating system for fishery's farm is operated very severe combating corrosion due to high accumulation by feeding material and high temperature in heated sea water. Almost all manufactured heaters of STS 316L and Ti material are scrapped every year due to heavy corrosion such a general and crevice corrosion. For comparing the general and galvanic corrosion in new heater material, the test material of Zirconium (Zr), Titanium (Ti) and STS 316L are tested by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), current density-time methods and microscopic examination in a 3.5% NaCl solution. The corrosion potential (Ecor) measured by potentiodynamic polarization for Zr, Ti and STS 316L reveals -198, -250 and -450mV, corrosion current density 0.5, 2.5 and $6.5{\mu}A/cm^2$ respectively. The film resistance measured by EIS are Zr 63,000, Ti 39,700 and 316L $3,150{\Omega}$, and the current of Zr-Ti couple is $0.03{\mu}A$, whereas Zr-316L SS is $0.1{\mu}A$. According to the result of this experiment in 3.5% NaCl solution, Zr is excellent corrosion resistance material than Ti and STS 316L.

• Journal of the Korean Ceramic Society
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• v.40 no.8
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• pp.751-757
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• 2003

Rapid densification of a SiC-30 wt% TiC powder with additive 10 wt% A1$_2$O$_3$-Y$_2$O$_3$-CaO was conducted by Spark Plasma Sintering(SPS). The fully-densified materials can be obtain through the SPS process with very fast heating rate and short holding time. In the present work, the heating rate and applied pressure were kept to be $100^{\circ}C$/min and 40 MPa, while sintering temperature varied from $1600^{\circ}C$ to $1800^{\circ}C$ for 10 min. The full densification of SiC-30 wt% TiC composites with the addition of $Al_2$O$_3$, $Y_2$O$_3$ and CaO was achieved at the temperature above $1700^{\circ}C$ by spark plasma sintering. The XRD found that 3C-SiC and TiC were maintained the entire SPS process temperature, without phase transformation of SiC and formation of YAG phase to $1800^{\circ}C$. The microstructures of the rapidly densified SiC-30 wt% TiC composites consisted of smaller equiaxed SiC grains and larger TiC grains. The biaxial strength of 635.2 MPa and fracture toughness of 6.12 MPaㆍ$m^{1/2}$ were found for the specimen prepared at $1750^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.54-61
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• 1999

A study was conducted to find a rapid thawing method which prevents excessive drip loss and local overheating. Effects of thawing methods (conventional thawing vs. 2,450 and 915 MHz microwave thawing) on thawing time, temperature profile, drip loss, water holding capacity, total color difference and total aerobes were investigated. Samples were thawed at 4, 28 and $50^{\circ}C$ in a refrigerator or an oven for the conventional thawing methods the convertional thawing methods. Power levels of 5, 10 and 15 kW were used for 915MHz microwave thawing. Cotreatment of 915 MHz microwave and convectional heating $(120^{\circ}C)$ was tested. 915 MHz microwave accelerated the thawing rate, and showed significant effects on penetration depth, drip loss, water holding capacity and total aerobes. Cotreatment of 915 MHz microwave and convection heating was appeared to be a suitable thawing process for the food industry.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.4
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• pp.654-659
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• 1994

To elucidate the relationship between physical and chemical properties of frying vegetable oils, soybean oil and cottonseed oil were heated in air temperatures from $160^{\circ}C\;to\;220^{\circ}C$ for 60 hours. Acid value, carbonyl value, iodine value, viscosity and content of polymer were remarkably changed as higher heating temperature and/or longer heating time. Correlation coefficient of viscosity to acid value was 0.9843 for soybean oil and 0.9819 for cottonseed oil. In case of viscosity and carbonyl value, viscosity also showed good relationship to carbonyl value as 0.9779 for soybean oil and 0.9797 for cottonseed oil. And correlation coefficient of viscosity to iodine value of soybean oil was 0.9852 and cottonseed oil was 0.9948.

• Journal of Biosystems Engineering
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• v.23 no.3
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• pp.229-244
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• 1998

This study was performed to determine proper fan and heater management schemes for natural air drying of rough rice in round steel bin with stirring device under Korean weather conditions. A computer simulation model was developed to predict moisture content changes, energy requirements, and drymatter losses during drying of rough rice by natural air. Drying test was conducted to validate the simulation model using round steel bin of holding capacity of 300ton at Rice Processing Complex in Jincheon. The bin was filled with rough rice every day and mixing by stirring device. Moisture contents, ambient air temperatures, relative humidities, static pressures in plenum chamber in the bin, airflow rates, and electrical and fuel energy were measured. Relative errors of moisture content changes predicted by the simulation model were below 5ft, and relative errors of final moisture content, final grain weight, required energy ranged from 0.9% to 6%. These not levels indicated that the simulation model can satisfactorily predict the performance factors of natural air drying system such as drying rates and energr consumptions comparing error level of 10% to 15% in other drying simulation models generally used in dryer desists. Twelve different fan and heater management schemes were evaluated using the computer simulation model based on three hourly weather data from Suweon for the period of 1952-1994. The best management schemes were selected comparing the drymatter losses, required drying times, required energy consumptions. Operating fan without heating only when ambient relative humidity was below 85% or 90% appeared to be the most effective method of In operation in favorable drying weather. Under adverse drying climates or to reduce required drying time, operating fan continuously, and heating air with $1.5^{\circ}C$ temperature rise only when ambient relative humidity was over 85% appeared to be the most suitable method.