• Bulletin of the Korean Chemical Society
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• 제33권8호
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• pp.2475-2476
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• 2012

• 자원환경지질
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• 제42권3호
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• pp.195-206
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• 2009

함양-산청지역 하상퇴적물의 자연배경치와 부화특성을 알아보고, 지구화학적 재해에 대해 예견하였다. 오염의 우려가 없고, 집수분지를 대표할 수 있는 하상퇴적물 시료를 채취하였다. XRF, ICP-AES와 NAA 분석을 이용하여 주성분원소와 유해원소 함량을 얻었다. 산분해법은 1차로 $HClO_4$와 HF를 혼합하여 $200^{\circ}C$에서 분해시킨 후, 2차로 $HClO_4$, HF 및 HCl를 혼합한 후 $200^{\circ}C$에서 분해시켜 이를 1% $HNO_3$용액으로 만들었다. 상관분석에서 하상퇴적물의 $SiO_2$ 함량이 증가할수록 Cu와 Co의 함량이 감소하는 특징을 보임을 알 수 있었다. 함양-산청내 환경유해원소 대부분 부화지수 2 이하로 부화되어 있었으며, 함양지역 하상퇴적물은 Pb>Th>Cr>V>Co>Cu순으로, 산청지역 하상퇴적물은 Pb>Th>Cr>Co>V>Cu순으로 부화되어 있었다. Pb, Cr, Co 및 V의 부화지수는 함양지역과 산청지역에서 거의 비슷한 부화특성을 보였으나, Th의 부화지수는 함양지역 지역에서, Cu의 부화지수는 산청지역에서 높은 부화특성을 보였다. Pb의 부화지수는 각각 2.24(함양), 2.57(산청) 이상으로 부화되어 있었지만, 토양 및 환경오염 허용 한계치(tolerable level)를 이용하여 살펴본 결과에서는 오염에 특별히 노출되지 않은 것으로 판단된다.

• 한국가스학회지
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• 제11권4호
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• pp.17-22
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• 2007

비예혼합 대향류화염에서 산소부화에 따른 NOx 생성특성에 관한 수치해석이 수행되었다. 순산소의 연소과정에서 공기침투에 의한 부득이한 질소 유입의 상황을 체계적으로 고려하기 위하여, 산화제의 $O_2$는 체적비 21%에서 100%까지 변화되었다. 결과적으로 NO 배출지수$(EI_{NO})$는 산소부화율 75%까지 증가하다가 급격히 감소하는 경향을 보여준다. 이러한 경향은 화염온도, 화염두께 및 체류시간 보다는 NOx 생성과 관련된 $N_2$ 소모율 변화에 의해 설명될 수 있음을 확인하였으며, 특히 N+NO=$N_2+O$ 반응이 가장 크게 기여함을 알 수 있었다.

• 자원환경지질
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• 제31권2호
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• pp.111-125
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• 1998

Dispersion, migration and enrichment of environmental toxic elements from the Samkwang Au-Ag mine area were investigated based upon major, minor and rare earth element geochemistry. The Samkwang mine area composed mainly of Precambrian granitic gneiss. The mine had been mined for gold and silver, but closed in 1996. According to the X-ray powder diffraction, mineral composition of stream sediments and soils were partly variable mineralogy, which are composed of quartz, orthoclase, plagioclase, amphibole, muscovite, biotite and chlorite, respectively. Major element variations of the host granitic gneiss, stream sediments and soils of mining and non-mining drainage, indicate that those compositions are decrese $Al_2O_3$, $Fe_2O_3$, MgO, $TiO_2$, $P_2O_5$ and LOI with increasing $SiO_2$ respectively. Average compositional ranges (ppm) of minor and/or environmental toxic elements within those samples are revealed as As=<2-4500, Cd=<1-24, Cu=6-117, Sb=1-29, Pb=17-1377 and Zn=32-938, which are extremely high concentrations of sediments from the mining drainage (As=2006, Cd=l1, Cu=71, Pb=587 and Zn=481 ppm, respectively) than concentrations of the other samples and host granitic gneiss. Major elements (average enrichment index=6.53) in all samples are mostly enriched, excepting $SiO_2$, $Na_2O$ and $K_2O$, normalized by composition of host granitic gneiss. Rare earth element (average enrichment index=2.34) are enriched with the sediments from the mining drainage. Minor and/or environmental toxic elements within all samples on the basis of host rock were strongly enriched of all elements (especially As, Br, Cu, Pb and Zn), excepting Ba, Cr, Rb and Sr. Average enrichment index of trace elements in all samples is 15.55 (sediments of mining drainage=37.33). Potentially toxic elements (As, Cd, Cr, Cu, Ni, Pb, and Zn) of the samples revealed that average enrichment index is 46.10 (sediments of mining drainage=80.20, sediments of nonmining drainage=5.35, sediments of confluent drainage=20.22, subsurface soils of mining drainage=7.97 and subsurface soils of non-mining drainage=4.15). Sediments and soils of highly concentrated toxic elements are contained some pyrite, arsenopyrite, sphalerite, galena and goethite.

• Nuclear Engineering and Technology
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• 제48권2호
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• pp.351-359
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• 2016

The Korean Prototype Gen-IV sodium-cooled fast reactor (PGSFR) is supposed to be loaded with a relatively-costly low-enriched U fuel, while its envisaged transuranic fuels are not available for transmutation. In this work, the U-enrichment reduction by improving the neutron economy is pursued to save the fuel cost. To improve the neutron economy of the core, a new reflector material, PbO, has been introduced to replace the conventional HT9 reflector in the current PGSFR core. Two types of PbO reflectors are considered: one is the conventional pin-type and the other one is an inverted configuration. The inverted PbO reflector design is intended to maximize the PbO volume fraction in the reflector assembly. In addition, the core radial configuration is also modified to maximize the performance of the PbO reflector. For the baseline PGSFR core with several reflector options, the U enrichment requirement has been analyzed and the fuel depletion analysis is performed to derive the equilibrium cycle parameters. The linear reactivity model is used to determine the equilibrium cycle performances of the core. Impacts of the new PbO reflectors are characterized in terms of the cycle length, neutron leakage, radial power distribution, and operational fuel cost.

• 자원환경지질
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• 제30권6호
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• pp.553-566
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• 1997

Origin, behavior and enrichment of environmental toxic elements from the Deokpyeong area were investigated on the basis of major, trace and rare earth element geochemistry. Coaly metapelites of the Deokpyeong area are subdivided into grey phyllite, dark grey phyllite, coaly slate and black slate, which are interbedded along the Ogcheon Supergroup. The coaly slate had been mined for coal, but mining is closed. The coaly and black slates are lower contents of $SiO_2$ and $Al_2O_3$, and higher contents of LOI, CaO, $Na_2O$ and BaO as compared with the phyllitic rocks. Rare earth elements are highly enriched in the coaly and black slate. Average compositions (ppm) of minor and/or environmental toxic elements in the coaly and black slate are revealed as As=127, Ba=30,163, Cd=18, Cr=740, Cu=84, Mo=378, Pb=43, Sb=12, Se=44, U=144, V=8,147 and Zn=292, which are extremely high concentrations than those in the NASC compositions. Major elements (average enrichment index; 5.34) in the coaly metapelites are mostly depleted, excepting $P_2O_5$ and BaO, normalized by NASC. Rare earth elements (average enrichment index; 1.48) are enriched in the coaly slate. On the basis of NASC, minor and/or environmental toxic elements in the coaly metapelites were strongly enriched of all the elements with the exception of Co, Cs, Ni and Sr. Average enrichment index of trace elements in coaly metapelite is 31.51 (coaly slate; 51.94 and black slate; 15.46). Especially, enrichment index of potentially toxic elements (As, Ba, Cr, Cu, Mo, Ni, Sb, Se, U, V and Zn) of the rock is 46.10 (grey phyllite; 7.15, dark grey phyllite; 4.77, coaly slate; 88.96 and black slate; 22.11). These coal formations were deposited in basin of boundary between terrestrial and marine environments deduced to carbon, sulfur (C/S=2.2 to 275.7), trace and rare earth elements characteristics. Irregular behavior and dispersion between major, minor and rare earth elements of those metapelites indicates a variable source materials, incomplete mixing of differential source and/or reequilibrium of diagenesis and metamorphism.

• 자원환경지질
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• 제31권4호
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• pp.297-310
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• 1998

Geochemical characteristics of environmental toxic elements at the Narim mine area were investigated on the basis of major, minor, rare earth element geochemistry and mineralogy. Ratios of $Al_2O_3/Na_2O$ and $K_2O/Na_2O$ in soils and sediments range from 11.57 to 22.21 and from 1.86 to 3.93, and are partly negative and positive correlation against $SiO_2/Al_2O_3$ (3.41 to 4.78), respectively. These suggested that sediment source of host granitic gneiss could be due to rocks of high grade metamorphism originated by sedimentary rocks. Characteristics of some trace and rare earth elements of V/Ni (0.33 to 1.95), Ni/Co (2.00 to 6.50), Zr/Hf (11.27 to 53.10), La/Ce (0.44 to 0.55), Th/Yb (4.07 to 7.14), La/Th (2.35 to 3.93), $La_N/Yb_N$ (6.58 to 13.67), Co/Th (0.63 to 2.68), La/Sc (3.29 to 5.94) and Sc/Th (0.49 to 1.00) are revealed a narrow range and homogeneous compositions may be explained by simple source lithology. Major elements in all samples are enriched $Al_2O_3$, MgO, $TiO_2$ and LOI, especially $Fe_2O_3$ (mean=7.36 wt.%) in sediments than the composition of host granitic gneiss. The average enrichment indices of major and rare earth elements from the mining drainage are 2.05 and 2.91 of the sediments and are 2.02 and 2.60 of the soils, normalizing by composition of host granitic gneiss, respectively. Average composition (ppm) of minor and/or environmental toxic elements in sediments and soils are Ag=14 and 1, As=199 and 14, Cd=22 and 1, Cu=215 and 42, Pb=1770 and 65, Sb=18 and 3, Zn=3333 and 170, respectively, and extremely high concentrations are found in the subsurface sediments near the ore dump. Environmental toxic elements were strongly enriched in all samples, especially As, Cd, Cu, Pb, Sb and Zn. The level of enrichment was very severe in mining drainage sediments, while it was not so great in the soils. Based on the EPA value, enrichment index of toxic elements is 8.63 of mining drainage sediments and 0.54 of soils on the mining drainage. Mineral composition of soils and sediments near the mining area were partly variable being composed of quartz, mica, feldspar, amphibole, chlorite and clay minerals. From the gravity separated mineralogy, soils and sediments are composed of some pyrite, arsenopyrite, chalcopyrite, sphalerite, galena, goethite and various hydroxide minerals.

• Bulletin of the Korean Chemical Society
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• 제21권8호
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• pp.801-804
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• 2000

A crossed beam scattering of a $Pb(ZrxTi1-x)O_3plume$ and an oxygen jetwas studied by using a time-of-flight quadrupole mass spectroscopy. Both simple collisions and reactive scatterings had significant effects on the transportand energetics of ions in the plume. Relative enrichment of metal and metal oxide ions was also changed with the oxygen pulse because of the differences in the mass and chemical properties of the ions. In particular, an anomalous increase ofPb+ ions was observed as the oxygen jet crossed the plume at high laserfluences, while the signal magnitudes of alI other ions were reduced. This originates from the fact that PbO+ ions dissociate easily to liberate Pb+ ions inthe plume since the bond energy of PbO+ is as low as 2.2 eV.

• 대한기계학회논문집B
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• 제35권8호
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• pp.839-845
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• 2011

산소부화 조건의 $CH_4/O_2/N_2$ 화염에서 트리플루오르메탄의 영향을 조사하기 위해 1기압에서 자유롭게 전파하는 예혼합 화염에 대한 수치해석을 수행하였다. 트리플루오르메탄은 화염속도 감소에 기여하며, 감소의 크기는 화학적 효과보다 물리적 효과에 의해 더 크다. 트리플루오르메탄은 산소부화된 $CH_4/O_2/N_2$ 화염에서 더 많이 첨가되고 소비될 수 있다. 트리플루오르메탄은 주로 $CF_3{\rightarrow}CF_2{\rightarrow}CF{\rightarrow}CF:O{\rightarrow}CO$을 통해 분해되고, 산소부화 화염에서 $CHF_3+M{\rightarrow}CF_2+HF+M$이 중요한 역할을 한다. 억제제가 산소 부화 화염에 첨가함에 따라 활성기 최대 농도의 위치는 상대적으로 낮은 온도로 이동하고, OH의 순생성률은 H의 순생성률보다 높다.

• Mass Spectrometry Letters
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• 제6권2호
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• pp.31-37
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• 2015

Phosphorylation upon protein is well known to a key regulator that implicates in modulating many cellular processes like growth, migration, and differentiation. Up to date, grafting of multidimensional separation techniques onto advanced mass spectrometry (MS) has emerged as a promising tool for figuring out the biological functions of phosphorylation in a cell. However, advanced MS-based phosphoproteomics is still challenging, due to its intrinsic issues, i.e., low stoichiometry, less susceptibility in positive ion mode, and low abundance in biological sample. To overcome these bottlenecks, diverse techniques (e.g., SCX, HILIC, ERLIC, IMAC, TiO₂, etc.) are continuously developed for on-/off-line enrichment of phosphorylated protein (or peptide) from biological samples, thereby helping qualitative/quantitative determination of phosphorylated protein and its phosphorylated sites. In this review, we introduce to the overall views of enrichment tools that are universally used to selectively isolate targeted phosphorylated protein (or peptide) from ordinary ones before MS-based phospoproteomic analysis.