• Transactions of Materials Processing
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• v.32 no.3
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• pp.160-165
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• 2023

As the supply of eco-friendly vehicles increases, the application rate of hot stamping components is rising to reduce vehicle weight and improve safety. Although Al-Si coated steel sheets are commonly used in hot stamping processes, their manufacturing costs are elevated due to process patents and royalties. Various hot stamping studies have been conducted to reduce these production costs. In this study, we derived a process control method for suppressing the oxide layer of hot stamping parts using uncoated boron steel sheets. Firstly, hat-shaped parts were hot stamped under atmospheric conditions to analyze the tendency of oxide layer formation by location. Then, the Gleeble system was used to observe oxide layer formation based on oxygen content under various atmospheric conditions. Finally, the oxide layer thickness was quantitatively measured using SEM images.

• Journal of Korean Society for Atmospheric Environment
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• v.31 no.3
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• pp.223-238
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• 2015

The $PM_{2.1}$ was collected by LVCI (low volume cascade impactor) during Group-A Period (September 1990 to December 2012) and the $PM_{2.5}$ was collected by HVAS (high volume air sampler) during Group-B Period (September 2009 to April 2012) at Kyung Hee University, Global Campus located on the boarder of Yongin and Suwon. The 8 water-soluble ions ($Na^+$, $NH_4{^+}$, $K^+$, $Mg^{2+}$, $Ca^{2+}$, $Cl^-$, $ NO_3{^-}$, and $SO_4{^{2-}}$) were analyzed by IC, and the 14 inorganic elements (Al, Mn, Si, Fe, Cu, Pb, Cr, Ni, V, Cd, Ba, Zn, Ti, Ag) were analyzed by XRF and ICP-AES after performing proper pre-treatments of each sample filter. The average total mass fractions of $SO_4{^{2-}}$, $NO_3{^-}$, and $NH_4{^+}$+ to $PM_{2.5}$ samples during Group-B Period were 0.39 in normal days, 0.44 in haze days, and 0.27 in Asian dust days, respectively; however, the average total mass fractions of Al, Fe, and Si to $PM_{2.5}$ mass were 0.043 in normal days, 0.021 in haze days, and 0.036 in Asian dust days, respectively. Especially the concentration of Pb was significantly decreased during Group-B Period rather than during Group-A Period, while Cr and Ni was increased during Group-B Period. In this study, we intensively compared the annual and seasonal patterns of major chemical species among normal days, haze days, and Asian dust days. Further we developed mass fraction profiles by collecting episode cases of haze days and Asian dust days, which were consisting of 22 chemical species. Those profiles are considered to be useful when applying various receptor models and establishing air quality management plans near future.

• Economic and Environmental Geology
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• v.45 no.6
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• pp.643-659
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• 2012

The Chungju Fe-REE deposit is located in the Kyemyeongsan Formation of the Ogcheon Group. The Kyemyeongsan Formation includes meta-volcanic rocks and pegmatite hosted REE deposit which show different kind of REE-containing minerals. The meta-volcanic rocks hosted REE deposits' main REE minerals are allanite, zircon, apatite, and sphene, whereas the pegmatite hosted REE deposits is mainly composed of fergusonite, and karnasurtite, zircon, thorite. The meta-volcanic rock hosted major REE mineral is allanite as the form of aggregation and contains 23.89-29.19 wt% TREO (Total Rare Earth Oxide), 4.71-9.92 wt% $La_2O_3$, 11.30-14.33 wt% $Ce_2O_3$, 0.11-0.29 wt% $Y_2O_3$, 0.15-0.94 wt% $ThO_2$, as a formula of (Ca, Y, REE, Th)$_{2.095}$(Mg, Al, Ti, Mn, $Fe^{3+})_{2.770}(SiO_4)_{2.975}(OH)$. Accompanying REE in a coupled substitution for $Ca^{2+}$ (M1 site) and $Al^{3+}-Fe^{2+}$ (M2 site) leads to a large chemical variety. Due to the allanite's high contents of Fe, it belongs to Ferrialanite. The pegmatite hosted deposit's domi-nant REE mineral is fergusonite as prismatic or subhedral grains associated with zircon, fluorite and karnasurtite. Geochemical composition of the fergusonite($YNbO_4$) suggests substitution of Y-REE and Y-Th in A-site, and Nb-Ta-Ti in B-site, furthermore the proportion of $Y_2O_3$ and $Nb_2O_5$ is oddly 1:1.5 comparing to the ideal ratio 1:1 and Nb is higher than Y, also A-site Y actively substitutes with REE. Karnasurtite in pegmatite variously ranges 9.16-22.88 wt% $Ce_2O_3$, 2.15-9.16 wt% and $La_2O_3$, 0.44-10.8 wt% $ThO_2$, as a calculated formula (Y, REE, Th, K, Na, Ca)$_{1.478}(Ti, Nb)_{1.304}$(Mg, Al, Mn, $Fe^{3+})_{0.988}$(Si, P)$_{1.431}O_7(OH)_4{\cdot}3H_2O$. Firstly the 870-860 Ma is the initial age of the supercontinent Rhodinia dispersal and subsequent A-1 type volcanism, which contains Fe, REE, and HFS(High Field Strength elements; Nb, Zr, Y etc.) elements in Fe-rich meta-volcanic rocks dominant Kyemyeongsan Formation, might mineralized allanite. Another synthesis is that regional metamorphism at late Paleozoic 300-280 Ma(Cho et al., 2002) might cause allanite mineralization. Also pegmatite REE mineralization highly related to the granite intrusion over the Chungju area in Jurassic(190 Ma; Koh et al., 2012). Otherwise above all, A-1 type volcanism at the same time of the Kyemyeongsan Formation development, regional metamorphism and pegmatite, might have caused REE mineralization. Although REE ore bodies display a close spatial association, each ore bodies display temporal distinction, different mineral assemblage and environment of ore formation.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.819-825
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• 1995

Two sweet potato CV.(Ipomoea batatas) were examined, i.e. purple flesh sweet potato(PSP) and light yellow flesh sweet potato(LYSP) which varied in degree of sweetness. On a fresh weight basis, nitrogen free extract in cultivars ranged from $25.73{\sim}26.24%$ and PSP contained more crude fat than LYSP. Total amino acids of PSP and LYSP were 5676.57mg% and 4550.86mg%, respectively. Aspartic acid, serine, alanine and valine were the major components in sweet potatoes. Sulfur-containing amino acids are the first limiting amino acid in PSP. The major fatty acids in PSP and LYSP analyzed by GC were palmitic acid, linoleic acid. The content of the saturated fatty acid was less than that of the unsaturated fatty acid. Carbohydrate contents were $75.43{\sim}79.10%$ and neutral sugars contents were $67.22{\sim}64.85%$(dry wt). Two sweet potato CV. contained the most glucose of all neutral sugars. PSP contained 11.88% for uronic acid, 59.42% for starch. Free sugars of PSP(0.82%) was much less than that of LYSP(2.53%). The contents of thiamin, riboflavin and niacin were similar, and the ascorbic acid contents in PSP and LYSP were 63.4mg% and 48.7mg%(dry wt), respectively. Comparing the mineral content in PSP, K was the greatest element in concentration followed by mg, Ca, Na. The total dietary fiber(TDF) value was 13.43% in PSP, 9.79% in LYSP respectively. The ratio of soluble dietary fiber(SDF) content and insoluble dietary fiber(IDF) content to TDF content for PSP were 57.6%, 42.4%, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.631-636
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• 2010

One experiment was carried out to investigate the soil chemical properties of bracken growth and the inorganic element contents of plant. To the results of soil analysis in native bracken (Pteridium aquilinum L.) growth, soil pH was 5.2, organic matter was 19 g $kg^{-1}$ and available phosphate was 20 mg $kg^{-1}$, and exchangeable potassium, calcium, magnesium were 0.32, 2.0 and 1.3 $cmol_c\;kg^{-1}$, respectively. In the bracken cultivation soil, pH was 5.7, organic matter was 13 g $kg^{-1}$ and available phosphate 367 mg $kg^{-1}$, and exchangeable potassium, calcium and magnesium were 0.81, 4.0 and 1.4 $cmol_c\;kg^{-1}$, respectively. The soil pH, available phosphate and exchangeable calcium were much lower in bracken native soil than those of cultivation soil, while organic matter was a little higher in native soil than that of cultivation soil. In native bracken plants, three major elements of nitrogen, phosphorus and potassium, were 4.40, 0.55 and 3.40%, calcium and magnesium were 0.22 and 0.32%, and microelements of iron (Fe), manganese (Mn), copper (Cu), zinc (Zn) and boron were 126, 210, 23, 75 and 11 mg $kg^{-1}$, respectively. In cultivation bracken, three major elements of nitrogen, phosphorus and potassium, were 5.50, 0.73 and 3.55%, calcium and magnesium were 0.17 and 0.28%, and microelement contents of iron (Fe), manganese (Mn), copper (Cu), zinc (Zn) and boron (B) were 120, 252, 19, 72 and 20 mg $kg^{-1}$, respectively.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.4
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• pp.318-325
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• 2002

Cooking characteristics of coated rice with water homogenate of citrus fruit peels (1% for rice) were investigated. The color of the coated rice both before and after cooking was dark yellow. The total content of carotenoids, hesperidin and naringin were 10.74, 2173.12 and 1468.40 mg% for citrus fruit peels, 0.46, 108.65 and 73.35 % for its water homogenate, 0.12, 21.73 and 14.62 mg% for coated rin, and 0.05, 8.67 and 5.87 mg% fur cooked coated rice, respectively. Citrus fruits peel contained 94.22 mg% of asparagine, 24.88 mg% of methionine, 19.64 mg% of alanine, and 15.37 mg% of ${\gamma}$-aminoisobutyric acid as the majority free amino acids, accounting for 70% of the total free amino acids present. Total free amino acid content of the cooked coated rice increased by 15% compared to those of cooked uncoated rice. The majority of minerals in the citrus fruit peels were K and Ca, accounting for 56% of total minerals present. The mineral content of cooked coated rice was generally higher than that of the cooked uncoated rice. The cooked coated rice showed comparable hardness, gumminess and brittleness, but higher cohesiveness and springiness than the cooked uncoated rice. There were no differences in sweet and bitter taste between the cooked uncoated and coated rice. However, the cooked coated rice showed higher sensory scores fur color acceptability, savory taste and overall acceptability than the cooked uncoated rice.

• Korean Journal of Environmental Agriculture
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• v.31 no.4
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• pp.328-343
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• 2012

BACKGROUND: For effective subwatershed management, it is very important to select the tributaries for improving water quality and understand the characteristics of tributaries. Until now, however, the case study of main streams has been managed. 17 tributaries in Geum river subwatershed were monitored to regulate the source of water contaminations and identify their current situations in this study. METHODS AND RESULTS: As pollution indicators, such as biological oxygen demand($BOD_5$), chemical oxygen demand($COD_{Mn}$), suspended solid(SS), total nitrogen (T-N), total phosphate(T-P) and total organic carbon(TOC) in Geum river were examined from January to December in 2011. The results were as follows : The annual average concentration of nutrients in Yongdam reservoir upsteam was 0.7 mg/L for BOD, 3.0 mg/L for COD, 8.4 mg/L for SS, 2.905 mg/L for T-N, 0.035 mg/L for T-P and 1.6 mg/L for TOC. Water quality of Daechung reservoir upstream was mostly similar tendency in comparison to Yongdam reservoir upstream. Among the 22 tributaries, water quality in Daechung reservoir downstream was more polluted. T-N contents were significantly high in Miho B4 located Daechung reservoir downstream(annual average concentration: 13.53 mg/L). In cases of Miho A1, A2 and C1, pollution degree was worsened during rainy season expecially. CONCLUSION(S): For improving water quality of Geum river subwatershed, the tributaries in the Mihocheon area should be preferentially considered. Mihocheon tributary is the highest in pollution site, and thus a study on long-term effects should be research.

• Clinics in Shoulder and Elbow
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• v.21 no.4
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• pp.192-199
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• 2018

Background: The currently available reverse shoulder arthroplasty (RSA) designs can be classified into medial glenoid/medial humerus (MGMH), lateral glenoid/medial humerus (LGMH), and medial glenoid/lateral humerus (MGLH) prosthesis designs. The purpose of this study was to radiologically analyze the effect of different RSA designs on humeral position following RSA. Methods: A total of 50 patients who underwent primary RSA were retrospectively analyzed. Among 50 patients, 33 patients (group A: MGMH) underwent RSA with Aequalis system (Wright, Inc, Bloomington, MN, USA), 6 (group B: LGMH) with Aequalis system using bony increased offset, and 11 (group C: MGLH) with Aequalis Ascend Flex system. The acromiohumeral distance, acromioepiphyseal distance (AED), lateral humeral offset (LHO), LHO from the center of rotation ($LHO^{COR}$), and deltoid length were radiologically measured to quantify the distalization and lateralization of the humerus. Results: The increment in postoperative AED was $19.92{\pm}3.93mm$ in group A, $24.52{\pm}5.25mm$ in group B, and $25.97{\pm}5.29mm$ in group C, respectively (p=0.001). The increment in postoperative LHO was $0.13{\pm}6.30mm$, $8.00{\pm}12.14mm$, and $7.42{\pm}6.88mm$, respectively (p=0.005). The increment in postoperative $LHO^{COR}$ was $20.76{\pm}6.06mm$, $22.04{\pm}5.15mm$, and $28.11{\pm}4.14mm$, respectively (p=0.002). Conclusions: The radiologic analysis of the effect of different RSA designs on humeral position following RSA showed significant differences in the increment in postoperative AED, LHO, and $LHO^{COR}$ between the 3 groups. Therefore, MGLH design seems to be more effective for humeral distalization and lateralization compared to original Grammont design.

• Journal of Nutrition and Health
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• v.34 no.1
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• pp.48-53
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• 2001

As the severity of environmental pollution increases, the foodstuffs are contaminated more the ever. There are 40 kinds of heavy metals that we are able to consume through the heavy metal contaminated-foodstuffs. Arsenic, lead, cadmium, and chromium out or them have been know to be a potential cause for a alzheimers disease, kidney diseases, and cancer. However, research data on the daily intakes of such heavy metals are limited. This study was performed to evaluate the daily intakes of nutrients and the dietary heavy metals of the college women living in Choongchung-NamDo Area, where had been reported to have high contents of heavy metals for the seafoods. We also investigated the blood levels of the heavy metals. The mean age, height, weight, BMI and percent ideal body weight(PIBW) of the subjects were 20$\pm$1.0yr, 158.4$\pm$0.7cm, 55.1$\pm$1.4kg, 22.4$\pm$.04, and 103.3$\pm$2.5 %, resp-ectivly. The mean of daily energy intake was 1,717.03$\pm$55.99kacl/day(86% of RDA for women). The ratio to energy from carbohydrate, fat and protein was 60: 24: 16. Daily intakes of Vit A, Vit B$_2$, CA, and Fe were under the RDA for those nutrients. The mean adequate ratio of the subjects was 0.92 . The daily intakes of heavy metal, such as As, Pb, Co, Cr and Mn , were 1.80$\pm$0.27mg, 75.21$\pm$4.12$\mu\textrm{g}$, 21.12$\pm$12.34$\mu\textrm{g}$, 60.07$\pm$6.24$\mu\textrm{g}$ and 6.23 $\pm$0.12mg respectively. the blood levels of As, Pb, Co, Cr and Mn were 16.10$\pm$2.10$\mu\textrm{g}$/dl, 4.32$\pm$0.58$\mu\textrm{g}$/dl, 0.02$\pm$0.01$\mu\textrm{g}$/dl, 4.23$\pm$0.41$\mu\textrm{g}$/dl, and 4.40$\pm$0.21$\mu\textrm{g}$/dl, respectively. In conclusion, daily intake of heavy metals for the college women living in Choongchung-NamDo area was lower than that of WHOs re-commendation, however, the blood levels of each heavy metals were higher than those of Japanese, american, and italian, There were no correlations between the dietary intakes and blood levels of each heavy metals. (Korean J Nutrition 34(1):48-53, 2001)

• 한국해양학회지
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• v.22 no.1
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• pp.43-56
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• 1987

A study on sedimentation, geochemical behavior and seismic stratigrapht of the continental shelf sediments along the Korea Strait and a part of south and southeast offshore area of the Korea Peninsula was carried out. In the inner shelf floor with depth ranging up to 80m zonal distribution patterns of mud, sandy silt, and silty sand were observed. In the outer shelf, however, coarse sandy sediments are dominant, and shills and gravels were frequently observed. These observations seem to confirm the Holocene sedimentary processes on the continental shelves off the south, south to east coasts of Korea discussed by Park (1985 and 1986) and Park and Choi (1986). The suface sediments (upper most 5cm thick)from selected 9 stations were analyzed for Al,Mn, Fe,Cr,Ni,Cu,Zn and Pb in order to study geochemical behavior of the sediments in the study area. All data were normalized to Al to com,pensate the size effect of the sediments.In general,inner shelf sediments show slight enrichment compared to the outer shelf sediments.In particular,Pb and Zn show heavy enrichment in most of the sediments.to degrees comparable to those observed at the polluted Kwangyang and Masan Bay sediments.Thus,it is considered that rapid migration or movement of fine-grained sediments in the study area does exist. Three seismic stratigraphic units were analyzed based on the seismic records.The acoustic basement the lower sedimentary deposit(B)and the upper deposit(A)were observed.The strong reflectivity R,in particular, between unit A and B is considered to be an erosinal unconformity during the last Glacial time.