• Applied Chemistry for Engineering
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• v.7 no.5
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• pp.925-937
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• 1996

Three types of mordenites treated by steaming($SM_{6.5}$), HF solution for $SM_{6.5}(FM_a)$ and HF solutlon+steaming for $SM_{6.5}(FM_b)$ were prepared and used as cracking catalysts of vacuum gas oil. These samples were analysed by XRF and XPS for average and surface Si/Al atomic ratio, XRD for unit cell constants, nitrogen adsorption/desorption for porosity, pyridine-IR for acidic properties. In comparison with three type samples, $SM_{6.5}$ had a lot of acid amount and showed micropore volume mostly(>85% to total volume). Dealuminated $FM_a$, compared with $SM_{6.5}$, was decreased a little in acid amount and improved for porosity. Also, $FM_b$ was decreased further in acid amount and developed in mesopore dramatically. The catalytic activity and the yield of gasoline, kerosine+diesel and branched aromatic over the modified mordenites which have developed mesopore were improved. This is due to limited access of diffusion of large molecules within pore of the modified mordenites.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.51-58
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• 2008

A series of oleic acid esters containing mercaptobenzothiazole and dialkylenedithiocarbamate, which are potential environmentally friendly lubricating grease additives, were synthesized as 90% yield through several method such as nucleophilic substitution of dialkyl amine and carbon disulfide, reduction reaction, and condensation reaction. The structures of the additives were confirmed by $^1H$-NMR, FT-IR and EA analysis. The additives (1 wt%) were soluble in 100 N BO except C4-DTC-OE and soluble in soybean oil. The tribological properties as lubricating additives in 100 N BO were evaluated using 4-ball tester and the results showed as follows: Bz-thia-OE < C4-DTC-OE < Pyrro-DTC-OE < C8-DTC-OE. Whereas, the 4-ball anti-wear properties were not shown in soybean oil.

• Applied Chemistry for Engineering
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• v.26 no.2
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• pp.224-228
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• 2015

The carbon precursor pitch from pyrolyzed fuel oil (PFO), by-product of Naphta cracking process (NCC), was prepared through heat and UV irradiation treatments with various concentrations of $AlCl_3$, which is a new pitch preparation method. The reformed pitches were characterized by measuring their elemental composition, chemical structure of components, molecular weight distribution, and softening point. The oxygen contents of reformed pitch increased as increasing $AlCl_3$ amounts on the other hand, the carbon and hydrogen contents were not nearly changed. UV irradiated reformed pitches were composed of more aromatic carbon compounds than that of using only heat-treatment without any UV irradiation. The addition of $AlCl_3$ catalyst was ineffective on the aromaticity of reformed pitches. The softening point of prepared pitches was in the range of $103.3{\sim}168.9^{\circ}C$. Also the yield of prepared pitch increased from 48% to 80% when 5 wt% of $AlCl_3$ was added during the heat and UV irradiation reforming. It is expected that the UV irradiation reforming method can be practical and helpful to produce high yields of pitches with diverse properties.

• Korean journal of food and cookery science
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• v.32 no.1
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• pp.50-57
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• 2016

In this study, kim (dried laver) bugak ("KB"), Aster yomena bugak ("SB"), and namul (vegetables)-kim bugak (combination of Aster yomena and kim) ("NB") were prepared and their quality characteristics were investigated. NB was made by slicing Aster yomena, seasoning it with perilla seeds, attaching it to kim and applying glutinous rice paste, followed by freeze-drying. SB had a higher oil absorption rate than KB, reflecting the high oil absorption rate of namul (here, Aster yomena). DPPH radical scavenging activity was highest for SB; whereas, NB had higher DPPH radical scavenging activity than KB, indicative of the higher antioxidant capacity of namul, as compared to kim. With longer storage period, moisture content tended to be increased, while maximum load, yield stress and hardness tended to be decreased. Overall preference was in the order of NB>KB>SB, without statistical significance. Acid value and peroxide value of NB, stored at $25^{\circ}C$ for 40 days, tended to be increased gradually but did not meet the criteria for rancidity. Therefore, NB could be stored at $<25^{\circ}C$ for > 40 days. Furthermore, it would be possible to make functional bugak using a variety of namul, as well as Aster yomena.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.6
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• pp.693-700
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• 1992

As an approach to study a new natural antioxidant for edible fats and oils, antioxidative fractions from acorn powder were characterized. The oxidative stabilities of soybean, palm, beef tallow, and lard oil containing the acorn active fraction extracted with various organic solvents were studied by determining the peroxide value during the storage at $60^{\circ}C.$ And this effective antioxidative components were isolated and identified by thin layer chromatography and high performance liquid chromatography. The proximate compositions of acorn powder were water 11.9~12.0%, protein 7.1~7.4%, starch 65.5~69.4%, fat 2.1~2.6%, fiber 2.1~3.6%, ash 2.4~2.6%, and total tannin 4.6~6.8%, respectively. The final yield of fraction extracted by sequential order of acetone : $H_2O$(1 : 1) and ethylacetate was 2.8~3.1%. Gallic acid, digallic acid and gallotannin were contained this final fraction. The main antioxidative activity was speculated due to the presence of gallic acid in acorn powder extract. The antioxidative activity was more effective in fat water emulsion than just fat system. Antioxidative activities measured by peroxide value were quite high in beef tallow and soybean emulsion, but low in lard and palm oil emulsion in the concentration of 200ppm acorn extract. Therefore, the addition of 200ppm acorn extract was suggested to expect effective antioxidation concentration in the reaction system.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.557-561
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• 1998

This study was conducted to investigate the functionality of soybean protein isolates extracted in acidic range (pH 2.0 and 3.0), neutral range (pH 7.0) and alkaline range (pH 10.0 and 12.0). The protein content of soybean protein isolates extracted at pH 3.0 was maximum (93.31%), but that of pH 7.0 was minimum (73.93%). The extraction yield of soybean protein isolates extracted at pH 3.0 was minimum (0.36%), but that of pH 12.0 was maximum (47.54%). The functionality (solubility, water absorption, oil absorption, foam capacity, foam stability, emulsion capacity and gelation) of soybean protein isolates was significantly influenced by pH of extraction medium. The soybean protein isolates extracted at pH 2.0 and 3.0 were more soluble at acidic ranges and those of pH 3.0 and 7.0 were more soluble at neutral ranges, but those of pH 2.0, 3.0, 7.0, 10.0 and 12.0 were more soluble at alkaline ranges than other ranges. The soybean protein isolates extracted at pH 2.0 and pH 12.0 gave greater water absorption, oil absorption and foam capacity than those extracted at pH 3.0, pH 7.0 and pH 10.0. And the emulsion capacity of soybean protein isolates was increased by the increase of extraction pH.

• Tunnel and Underground Space
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• v.16 no.3 s.62
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• pp.259-276
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• 2006

In rock mass subject to high in-situ stresses, the failure process of rock is dominated by the stress-induced fractures growing parallel to the excavation boundary. When the ratio of in situ stresses compared to rock strength is greater than a certain value, progressive brittle failure which is characterized by popping and spatting of rock debris occurs due to stress concentration. Traditional constitutive model like Mohr-Coulomb usually assume that the normal stress dependent frictional strength component and the cohesion strength component are constant, therefore modelling progressive brittle failure will be very difficult. In this study, a series of numerical analyses were conducted for surrounding rock mass near crude oil storage cavern using CW-FS model which was known to be efficient for modelling brittle failure and the results were compared with those of linear Mohr-Coulomb model. Further analyses were performed by varying plastic shear strain limits on cohesion and internal friction angle to find the proper values which yield the matching result with the observed failure in the oil storage caverns. The obtained results showed that CW-FS model could be a proper method to characterize essential behavior of progressive brittle failure in competent rock mass.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.82-89
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• 1998

Partial hydrolyzing condition for low-molecularized alginate and rheological properties such as viscosity, solubility, emulsitying ability, oil absorption capacity, bile acids binding and metal ion binding of the low-molecularized alginates from the sea mustard ( Undaria pinnatifida) and giant kelp (Macrocystis pyrifera) were investigated. Alginate from sea mustard was regularly hydrolyzed with the increase of HCl concentration in the range of 0.2 N to 0.5 N and with the prolonged reaction time at $100^{\circ}C$. The molecular weight of alginate was decreased to a part of 100 after hydrolysis for 50 min with 0.3 N HCl. The ratio of mannuronate to guluronate was increased with the acid hydrolysis and total yield was estimated to be $75\%\~80\%$. Low-molecularization of alginate was featured in the apparent decrease of viscosity, whereas solubility, emulsifying ability, and bile acids binding ability were increased with the low-molecularization. Oil absorption capacity of the acid$\cdot$alkali soluble alginate was slightly higher than that of the water soluble alginate. Metal ion binding capacity was the highest in acid$\cdot$alkali soluble alginate, and decreased with the low-molecularization.

• Korean Journal of Plant Resources
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• v.36 no.5
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• pp.446-454
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• 2023

This study aimed to assess the potential use of Paeonia lactiflora Pall. seed cake (PSC). The extraction yield of the PSC extract ranged from 22% to 45%, depending on the extraction solvent used. The PSC extract showed significantly higher levels of total polyphenols and flavonoids contents, and radical scavenging compared to the P. lactiflora seed oil (PSO) extract. The antibacterial activity of the PSC extract was superior to that of the positive control and remained effective for up to 48 hours. Furthermore, when the PSC extract was applied, it significantly reduced the inflammatory response induced by LPS, demonstrating the anti-inflammatory activity of PSC. This study confirmed the effective bioactivity not only in PSO, but also in the PSC extract, highlighting the potential of PSC as a bio-health ingredient.

• Korea Trade Review
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• v.48 no.4
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• pp.189-208
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• 2023

This paper analyzed the dynamic conditional correlation between the Korean ETS market, energy market and stock market. This paper conducted an empirical analysis using daily data of Korea's carbon credit trading price, WTI crude oil futures price, and KOSPI index from February 2, 2015 to December 30, 2021. First, the volatility of the three markets was analyzed using the GARCH model, and then the dynamic conditional correlations between the three markets were studied using the bivariate DCC-GARCH model. The research results are as follows. First, it was found that the Korean ETS market has a higher rate of return and higher investment risk than the stock market. Second, the yield volatility of the Korean ETS market was found to be most affected by external shocks and least affected by the volatility information of the market itself. Third, the correlation between the Korean ETS market and the stock market was stronger than that of the WTI crude oil futures market. This paper analyzed the correlation between the Korean ETS market, energy market, and stock market and confirmed that the level of financialization in the Korean ETS market is quite low.