• Journal of the Korean earth science society
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• v.34 no.1
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• pp.28-40
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• 2013

This study examined the geochemical characteristics, equilibrium temperature and pressure conditions, and oxygen isotopic ratios of mantle xenoliths from the various geological sites of the Korean peninsula. The results are as follows: (1) The ultramafic xenoliths from the Korean peninsula mainly consist of typical high magnesium olivine (MgO : 49.12-50.95 wt.%, Mg value: 90.1-92.2), corresponding to worldwide Cenozoic ultramafic xenoliths in chemical compositions. (2) The pressure-temperature conditions of ultramafic xenoliths in the Korean peninsula are from 854 to $1016^{\circ}C$ and 4.6 to 24.4 kbar. (3) The oxygen isotopic ratios (${\delta}^{18}O$) for olivines in ultramafic xenoliths range from 5.06‰ to 5.51‰, which are relatively uniform oxygen isotopic values and overlapped by the values of N-MORB and upper mantle peridotite (${\delta}^{18}O$: $5.2{\pm}0.2$‰). However, olivines of the ultramafic xenoliths from the Baegdusan and Chejudo have a relatively wide ${\delta}^{18}O$ values ranging from 5.07 to 5.51‰ and 5.07 to 5.45‰, respectively. Based on the results, this study suggests that the high ${\delta}^{18}O$ signature of the Baegdusan xenoliths give a hint that ~5% of the oxygen in typical EM2 sources originally derived from recycled sediments.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.1
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• pp.65-72
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• 2011

Purpose: The purpose of this study was to evaluate the level of electro-chemical corrosion and surface roughness change for the cases of Ti abutment connected to restoration made of base metal alloys. Materials and methods: It was hypothesized that Ni-Cr alloys in different compositions possess different corrosion resistances, and thus the specimens ($13{\times}13{\times}1.5\;mm$) in this study were fabricated with 3 different types of metal alloys, commonly used for metal ceramic restorations. The electrochemical characteristics were evaluated with potentiostat (Parstat 2273A) and the level of surface roughness change was observed with surface roughness tester. Paired t-test was used to compare mean average surface roughness (Ra) changes of each specimen group. Results: All specimens made of nickel-chromium based alloys, average surface roughness was increased significantly (P < .05). Among them, the Ni-Cr-Be alloy ($0.016{\pm}.007\;{\mu}m$) had the largest change of roughness followed by Ni-Cr ($0.012{\pm}.003\;{\mu}m$) and Ni-Cr-Ti ($0.012{\pm}.002\;{\mu}m$) alloy. There was no significant changes in surface roughness between each metal alloys after corrosion. Conclusion: In the case of galvanic couples of Ti in contact with all specimens made of nickel-chromium based alloys, average surface roughness was increased.

• Journal of the Korean Electrochemical Society
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• v.5 no.3
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• pp.99-105
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• 2002

This study investigated characteristics of ICR18650 batteries with different electrolyte compositions in the range of $80^{\circ}C\~-30^{\circ}C$. ICR18650 cells using $1M\;LiPF_6,\;EC:\;DEC:\;DMC(3:5:5)\;and\; 1M\;LiPF_6,\;EC:\;DEC:\;DMC:\;EMC(3:5:4:1)$ electrolyte systems, which DMC and EMC solvent were added in $1M\;LiPF_6,\;EC:\;DEC$ electrolytes have high specific energy in the wide range of temperature. The specific energy of ICR18650 batteries using $1M\;LiPF_6,\;EC:\;DEC:\;DMC(3:5:5)\;and\; 1M\;LiPF_6,\;EC:\;DEC;\:\;DMC:\;EMC(3:5:4:1)$ electrolyte at $-30^{\circ}C\;was\;64\%\;and\;59\%$ of room temperature$(25^{\circ}C)$, respectively.

• The Korean Journal of Petroleum Geology
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• v.7 no.1_2 s.8
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• pp.35-40
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• 1999

Chemical and isotopic compositions of hydrocarbon gases were analyBed to characterize the properties of the shallow gases distributed in the southeastern part of the Ulleung Basin, offshore Korea. Sediments from the core were also analyzed to determine the characteristics and relationship to shallow gases. Hydrocarbon gases in the sediments consisted of methane (697.9-6054.4 ppm), ethane, propane, butane and hexane. The total carbon content of the sediments ranges from 1.84fe to $5.11{\%}$ and the total organic carbon content ranges from $0.29{\%} \;to\; 2.65{\%}$. High C/N ratio (>10) indicates that input of terrestrial organic matter was prevalent at the time of deposition. The methane content and stable isotopic data indicate that hydrocarbon gases from the sediments are identified to be thermogenic gas and mixture of both biogenic and thermal gases. Based on the Rock-Eval and carbon isotopic data, the level of thermal maturity of organic matter in the sediments $(Tmax<425^{\circ}C)$ is lower than that of gas. It suggests that thermal gases in the sediments migrated from the deeper sediments than the penetrated depth.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.585-592
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• 2011

The enhancement of the cold-start capability of polymer electrolyte fuel cells is of great importance in terms of the durability and reliability of fuel-cell vehicles. In this study, vanadium oxide films deposited onto the flat surface of metallic bipolar plates were synthesized to investigate the feasibility of their use as an efficient self-heating source to expedite the temperature rise during startup at subzero temperatures. Samples were prepared through the dip-coating technique using the hydrolytic sol-gel route, and the chemical compositions and microstructures of the films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and field-emission scanning electron microscopy. In addition, the electrical resistance hysteresis loop of the films was measured over a temperature range from -20 to $80^{\circ}C$ using a four-terminal technique. Experimentally, it was found that the thermal energy (Joule heating) resulting from self-heating of the films was sufficient to provide the substantial amount of energy required for thawing at subzero temperatures.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.513-517
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• 2013

We investigated the properties of impregnated activated carbons, a commercial adsorbent for the individual protection equipment, and examined CO adsorption and oxidation to $CO_2$. The surface area, pore volume and pore size were measured for four commercial samples using Brunauer-Emmett-Teller/Barrett-Joyner-Halenda (BET/BJH), and atomic compositions of the sample surface were analyzed based on SEM/EDS and XPS. Impregnated activated carbons containing Mn and Cu for fire showed the catalytic CO oxidation to $CO_2$ with a high catalytic activity (up to 99% $CO_2$ yield), followed by the CO adsorption at an initial reaction time. On the other hand, C: for chemical biologial and radiological (CBR) samples, not including Mn, showed a lower CO conversion to $CO_2$ (up to 60% yield) compared to that of fire samples. It was also found that a heat-treated activated carbon has a higher removal capacity both for CO and $CO_2$ at room temperature than that of untreated carbon, which was probably due to the impurity removal in pores resulted in a detection-delay about 30 min.

• Food Science of Animal Resources
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• v.28 no.3
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• pp.319-326
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• 2008

This study evaluated the effects of adding levels of rice bran fiber on the chemical compositions, cooking characteristics and sensory properties of ground pork meat products. Meat products were produced with products containing 0% (control), 1%, 2%, 3%, 4%, and 5% and rice bran fiber. The control had the highest protein and fat contents, cooking loss, reduction in diameter, CIE L value and CIE a value of uncooked product, and CIE L value of cooked product. The meat product containing rice bran fiber had the higher ash, pH, and CIE b value than the controls. The addition of 5% rice bran fiber resulted in the lowest cooking loss and L value of cooked meat products. Meat product with 2% rice bran had the highest water content, water holding capacity, hardness, color, tenderness, juiciness values. There was a significant difference among the ground meat products with respect to sensory properties, and meat products containing 1% and 2% rice bran had higher overall acceptability than the other meat products.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.6
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• pp.861-867
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• 2005

Feeding values of soybean hulls (SH) were compared to those of wheat bran (WB) for swine diets by chemical compositions, a digestion trial, a preference test by self-selection, and two feeding trials. The SH and the WB appeared to have, on airdry basis, 11.1 vs. 15.4% CP, 32.5 vs. 8.7% crude fiber (CF), 36.8 vs. 10.7% ADF, 0.6 vs. 0.1% Ca, and 492 vs. 92 ppm Fe, respectively. Lysine and total sulfur-containing amino acids in the SH were 0.66 vs. 0.37%, respectively. Apparent digestibility values of the SH were 71% for dry matter, 50% for CP, and 74% for CF. Apparent digestible energy and MEn values of the SH were 2,420 and 2,370 kcal kg$^-1$, respectively, which were comparable to those of the WB, 2,420 and 2,275 kcal kg$^-1$ (NRC, 1998), respectively. The first feeding trial was conducted with 72 crossbred growing pigs with an average weight of 29.6 kg. The pigs when fed the diets containing 0, 6 and 10% SH by replacing the WB on a weight basis for 42 days did not show significant differences in body weight gain and feed/gain ratio among the treatments. The same trends were observed in the second trial with 60 crossbred finishing pigs with an average weight of 64.5 kg when fed the diets containing 12% SH or WB for 41 days. Back-fat thickness and adjusted loin eye muscle area of the finisher pigs were also not significantly different between the two groups. When allowed to self-select from two different feed troughs containing 10% SH or WB for two weeks, two groups of 80 pigs with 10 pigs per pen consumed the two diets exactly in equal proportion. In conclusion, the soybean hulls can be included up to 10 and 12% for growing or finishing pig diets, respectively, replacing the wheat bran on a weight basis without any adverse effects on palatability of diets and animal performances.

• Korean Journal of Agricultural Science
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• v.23 no.1
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• pp.90-98
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• 1996

In order to obtain the basic information for new food product development from pheasant, wild duck(chhungdung), and Ogol fowl, which are called as special poultry, general components,fatty acid amino acid and minerals composition were analyzed. 1). The general compositions were 71.2-74.1% of water, 23.3-26.4% of protein, 1.0-2.4% fat, and 1.1-1.4% of ash in the pheasant, 73.8-76.4% of water, 18.6-19.6% of protein, 2.7-6.8% of fat, and 0.8-1.6% of ash in the wild duck, and 71.4-72.3% of water, 20.8-22.7% of protein, 1.9-6.3% of fat, and 1.0-1.2% of ash in the Ogol fowl, repectively. 2).In the pheasant and wild duck meat, the composition of unsaturated and saturated fatty acid were 60-64%,36-40%, respectively, and olec, palmitic, linolec, and stearic acid were most abundant in this order. But, in Ogol fowl, 72-76% and 24-28% were belong to the unsaturated fatty acid, respectively. 3). Amino acid contents in its order of relative amount were glutamic acid, alanine, aspatic acid, and glycine for the pheasant, glutamic acid, glycine, alanine, and aspatic acid for the wild duck, and lysine, glutamic acid, and aspatic acid for the Ogol fowl, repectively. 4).The mineral composition in the pheasant and wild duck were potassium, phosphorus, sodium, magnesium, and calcium, but in the Ogol fowl, potassium, sodium, magnesium, phosphorus, calcium were the most abundant in this order, repectively.

• Korean Journal of Plant Resources
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• v.9 no.3
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• pp.211-217
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• 1996

As a part of studies on the development of a Gugisuen(Lycium chinense M.), which is one of the unutilization of waste resources, we investigated the composition of fatty acid and amino acid according as picking period and varieties of Gugisuen. The chemical components of Gugisuen were as follows : 1. Proximate composition of Gugisuen were Cheongyang native had the highest contents of crude lipid, crude protein, total sugar, and the contents of crude protein, total sugar, and reducing sugar was the highest picked on June 20. 2. The contents of $P_2O_5$, $K_2O$, CaO, MgO, Cu, and Mn were higher in Cheongyang native than that of other varieties. And mineral contents of Gugisuen picked on May 10 were the highest. 3. The major fatty acids were linoleic, linolenic acids, and these unsaturated fatty acids composed about 50% of total fatty acids. Fatty acid compositions between each varieties were not significant, and those components were the highest in Gugisuen picked on May 10. 4. Eighteen amino acids were identified from Gugisuen, glutamic acid, the highest content was $10.05\sim10.94%$ and these contents increased in the order to aspartic acid > glycine > alanine > leucine > lysine. The contents of serine, arginine, methionine, cystine-2 and isoleucine were higher in late harvest time and glutamic acid and tryptophane were higher in early harvest time.