• Analytical Science and Technology
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• v.22 no.5
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• pp.422-431
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• 2009

The analytical results of wear metals such as Na, Mg, Al, Si, P, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Cd, Sn, Ba, Pb in oil samples are compared by portable and bench-top XRF methods as a basic study for the development of portable X-ray fluorescence spectrometer. The instrumental parameters such as measurement time of portable and bench-top XRF were optimized using certified reference materials of hydrocarbon oil with 20 wear metals in concentration range from 10 to 900 mg/kg. The analytical results of 20 wear metals in certified reference materials and new/used engine oil samples were compared by empirical and fundamental parameter methods.

• Journal of Powder Materials
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• v.20 no.4
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• pp.275-279
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• 2013

Fe-based oxide dispersion strengthened (ODS) powders were produced by high energy ball milling, followed by spark plasma sintering (SPS) for consolidation. The mixed powders of 84Fe-14Cr-$2Y_2O_3$ (wt%) were mechanically milled for 10 and 90 mins, and then consolidated at different temperatures ($900{\sim}1100^{\circ}C$). Mechanically-Alloyed (MAed) particles were examined by means of cross-sectional images using scanning electron microscopy (SEM). Both mechanical alloying and sintering behavior was investigated by X-ray diffraction (XRD) and high resolution transmission electron microscopy (HR-TEM). To confirm the thermal behavior of $Y_2O_3$, a replica method was applied after the SPS process. From the SEM observation, MAed powders milled for 10 min showed a lamella structure consisting of rich regions of Fe and Cr, while both regions were fully alloyed after 90 min. The results of sintering behavior clearly indicate that as the SPS temperature increased, micro-sized defects decreased and the density of consolidated ODS alloys increased. TEM images revealed that precipitates smaller than 50 nm consisted of $YCrO_3$.

• Journal of The Korean Society of Grassland and Forage Science
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• v.27 no.1
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• pp.29-36
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• 2007

A study was conducted to determine the trace minerals (Cu, Fe, Cd, Zn, Mo, Se, Mn, Cr, Co, Ni) levels in pasture soils and forages collected in Jeju area. Chemical characteristics and total or soluble trace minerals levels in 187 pasture soil samples (76 very dark brown and 111 black soils) were measured. Total trace minerals contents in hay samples of 60 Italian ryegrass, alfalfa and mixture grasses each were assessed. The pasture soils of Jeju were characterized to have low pH (5.1) and to contain low levels of available $P_2O_5$ (20.5 mg/kg) and exchangeable Ca, Mg, K, Na (2.6, 0.9, 0.5, 0.2 cmol+/kg, respectively) when comparing to upland soils of Jeju or Korean mainland. All trace elements in total or soluble analysis of pasture soils were detected, and there was a big difference between total and soluble levels. The pasture soils tended to have the higher total Fe, Mn, Ni and Zn contents. Cr in all forages was not detected, but other trace minerals levels showed normal range. The hay samples of Italian ryegrass and mixture grasses produced in Jeju tended to contain higher Mn (105 vs 23 mg/kg) and lower Mo (2.7 vs 4.9 mg/kg) than those of alfalfa hay imported from USA. Results show that trace minerals of pasture soils and forages in Jeju seem to be not deficient, indicating that supplementation of some trace minerals are not always necessary in diets for grazing animals and should be done after careful evaluation of diets with regard to concentrations and biological availability of essential elements.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.309-310
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• 2005

Some minor elements(Al, B, Ba, Ca, Cd, Co, Cr, Cu, Gd, Mg, Mn, Mo, Nd, Ni, P, Pb, Si, Sn, Sr, Ti, V, Yb, Zn and Zr) in iron compounds such as the S/G sludge of a power plant were separated from iron by anionic and cationic exchange methods. If a ICP-AES or AAS determination follows this method, minor elements of more than 2 or 20 ppm of Fe can be determined with an error less than 20% except Sn and Mo. Alkaline elements were excluded from this study since they can be easily recovered from an anionic exchange. Application to real sludge samples is ongoing.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.259-264
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• 1996

상용 Zircaloy-4보다 성능이 우수한 고연소도용 Zr 신합금을 개발하는 것을 목표로 외국에서 개발중인 12종의 신합금 피복관에 대한 특성평가, 부식기구 규명 연구, 국내에서 제조된 Zr 신합금의 특성평가를 실시하였다. 외국 피복관의 부식특성 평가로 부터 Sn을 0.6-1.0 wt.% 첨가하고 Nb을 0.4 wt.% 첨가하는 것이 내식성 관점에서 바람직함을 알 수 있었다. 여러 가지 LiOH용액에서의 부식기구 연구를 통해 수소화물이 부식가속의 원인임을 알 수 있었으며 수소화물 형성을 억제하는데는 Nb첨가가 효과적인 것으로 나타났다. 이와 같은 연구결과를 토대로 신합금의 개발방안을 수립하였으며 예비적으로 합금을 설계. 제조하여 특성시험을 실시한 결과, Zr-Sn-Nb-FeCr 합금이 우수한 내식성을 보이며 Fe, Mo는 강도 증가 효과가 큰 것으로 나타났다. 이러한 연구결과를 종합적으로 평가하여 신합금을 설계하고 노외성능 평가를 통해서 신합금을 선정한후, 단계적으로 하나로를 이용한 노내성능 평가를 실시할 예정이다.

• Nuclear Engineering and Technology
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• v.32 no.4
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• pp.372-378
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• 2000

The effect of alloying elements on the creep resistance of Zr alloys was investigated using thermal creep tests that were performed as a part of advanced fuel cladding development. The creep tests were conducted at 40$0^{\circ}C$ and 150 MPa for 240 hr. A statistical model was derived from the relationship between the steady-state creep rate and the content of individual alloying elements. The creep strengthening effect decreased in the following sequence : Nb, Sn, Mn, Cr, Mo, Fe and Cu. The high creep resistance of Sn and the opposite effect of Fe on zirconium alloys seem to be associated with their lowering and enhancing, respectively, the self-diffusivity of the zirconium matrix.

• Korean Journal of Plant Resources
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• v.4 no.2
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• pp.39-45
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• 1991

Proximate compositions of the roots of cultured and wild Codonopsis lanceolata were examined as tile basic reasearch for the study of their source of processed foods.No significant difference in the contents was found between the wild root and thecultivated at 3$0^{\circ}C$ in biotronroom. In view of the results to have measured mineralswhich is included in 14 sorts of Codonopsis lanceolata and surveyed their distribution.12 kinds of minerals including T1, Co, Ge, Sm, Mo, Sc, Be, Cd, As, Ga, Bi, ph are ne-vel or little included in almost source. Other twenty-one sorts of minerals (Ni, Se,Ba, Sb, Si, Ti, B, Li, Ifs, Ca, Sr, Mn, Fe, Cu, Zn, p, Al, Na, V, Cr, K) are more or less in-cluded in all source and Ca, Mg, p, K, and Fe are metals that are included in large qu-entities in comparison with others. No minerals difference in the contents was foundbetween the cultivated temperature. The content of elements of inorganic metal differsaccording to the part of C. lanceolata.

• YAKHAK HOEJI
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• v.43 no.5
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• pp.577-583
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• 1999

Concentrations of heavy metals, including As, Cd, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Se, Si, Sn, V and Zn in the internal organs (liver, kidney, heart, lung, spleen, cerebrum and bone) of Korean obtained from 91 forensic medical autopsy cadavers, with an age range of 12-87 years, were determined by inductively coupled plasma atomic emission spectrometry. From the results, positive correlation with age was observed in the following cases : Cd in liver, kidney and cerebrum; Fe in cerebrum and bone; Pb in bone; v in lung. Copper in heart, Hg in bone and Mn in kidney correlated negatively with age. A significantly positive correlation between Se and Hg was only observed in heart. Significant correlation coefficients between Se and As were observed in liver, kidney, heart spleen and bone. The correlation between Cd and Zn was significant in liver and kidney, indicating that the distribution of Cd is similar to that of Zn in the liver and kidney.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.77-78
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• 2011

저비용, 고효율, 안정적 수급이 가능한 전력 에너지원이 요구되면서 석탄이 새로운 에너지원으로 급부상하게 됨에 따라 차세대 친환경 석탄화력 발전기술인 IGCC (Integrated Gasification Combined Cycle) 발전 시스템 의 개발이 필요하게 되었다. 석탄가스화 공정(IGCC: integrated coal gasification combined cycle)은 석탄을 가스화한 후 이를 이용하여 복합발전소를 운전하는 발전기술로서 석탄을 고온, 고압아래에서 수소와 일산화탄소를 주성분으로 한 합성가스로 전환한 뒤 합성가스 중에 포함 된 분진과 황 화합물 등 유해물질을 제거하고 천연가스와 유사한 수준으로 정제하여 전기를 생산하는 친환경 발전 기술이다.

• Economic and Environmental Geology
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• v.30 no.3
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• pp.209-222
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• 1997

The Hoenam area, up the Taecheong lake, composed mainly of low grade coal-bearing metapelites within the Ogcheon Supergroup. These coal formations are developed discontinuously several hundred meters and swelling from 10 to 300 cm along the host metapelites. Although the formations have been mined for coal, but already mined out, and the formations were higher content (mean value of 42 samples) of environmental toxic elements as As (13 ppm). Ba (1.81 wt. %), Cd (2 ppm), Cr (188 ppm), Cu (87 ppm), Mo (214 ppm), Pb (25 ppm), Sb (3 ppm), Se (12 ppm), U (55 ppm), V (2124 ppm) and Zn (234 ppm) than the host metapelites and the NASC. The Al, Ti, Mg, K and Na contents in stream sediments derived from the Hando and Bugook mine area were highly concentrations than the samples from the Samseongjeil mine area. The mean value (wt. %) of Fe (10.07), Mn (0.15), Ca (0.84), P (0.18) and Ba (0.77) influenced by the Samseongjeil mine were higher than the other mine drainage sediments. The mean content (ppm) of environmental toxic elements in drainage sediments from the Samseongjeil mine were taken As (2083), Cu (447), Mo (202), Ni (720), Pb (42), U (250), V (1070) and Zn (2632), which are extremely high concentrations against NASC and EPA. Characteristics of elemental behavior and dispersion of the all toxic elements are the same as increased with increasing U, V, and Cu. Rare earth elements in the sediments are enriched with LREE (La, Ce and Nd) from the drainage on strong concentration of toxic elements. The pH of stream water is neutral, but pH of the sediments ranged from 4.92 to 6.93 (mean 6.22), those are slightly acid in the Hando mine area. Major elements in the host rocks at the Hoenam area are mostly depleted especially Ca, excepting Ti and Ba, normalized with NASC. The sediments were highly enriched of Ti, Fe, Mg, Mn and Ba, but depleted of Al, K, Ca, Na and P on the basis of host rocks and NASC. Minor and environmental toxic elements in the host rocks were strongly enriched all elements (As, Cd, Mo, Se, D, V and Zn), excepting Co, Ni and Sr. Enrichment index (mean value) about toxic elements (As, Cr, Cu, Fe, Ni, Pb and Zn) of the sediments in this area have taken 41.35 (Hando mine drainage; 2.73, Samseongjeil mine drainage; 113.14 and Bugook mine drainage; 8.19), those are seriously contaminated by environmental toxic elements.