• Analytical Science and Technology
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• v.32 no.6
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• pp.233-242
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• 2019

Substance identification is the first step of the REACH registration. It is essential in terms of Classification, Labelling and Packaging (CLP) regulation and because even trace amounts of impurities or additives can affect the classification. In this study, a scheme for the screening, quantification, and interpretation of trace amounts of hazardous inorganic substances is proposed to detect the presence of more than 0.1% hazardous inorganic substances that have been affecting the hazard classification. An exemplary list of hazardous inorganic substances was created from the substances of very high concern (SVHCs) in REACH. Among 201 SVHCs, there were 67 inorganic SVHCs containing at least one or ~2-3 heavy metals, such as As, Cd, Co, Cr, Pb, Sb, and Sn, in their molecular formula. The inorganic SVHCs are listed in excel format with a search function for these heavy metals so that the hazardous inorganic substances, including each heavy metal and the calculated ratio of its atomic weight to molecular weight of the hazardous inorganic substance containing it, can be searched. The case study was conducted to confirm the validity of the established scheme with zinc oxide (ZnO). In a substance that is made of ZnO, Pb was screened by XRF analysis and measured to be 0.04% (w/w) by ICP-OES analysis. After referring to the list, the presence of Pb was interpreted just as an impurity, but not as an impurity relevant for the classification. Future studies are needed to expand on this exemplary list of hazardous inorganic substances using proper regulatory data sources.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.158-158
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• 2003

수평 전기로에서 CuGaTe2 다결정을 합성하여 HWE 방법으로 CuGaTe2 단결정 박막을 반절연성 GaAs(100) 위에 성장하였다. CuGaTe2 단결정 박막은 증발원과 기판의 온도를 각각 67$0^{\circ}C$, 41$0^{\circ}C$로 성장하였다. 이때 단결정 박막의 결정성이 10K에서 측정한 광발광 스펙트럼은 954.5nm (1.2989eV) 근처에서 exciton emission 스펙트럼이 가장 강하게 나타났으며, 또한 이중결정 X-선 요동곡선(DCRC)의 반폭치(FWHM)도 139arcsec로 가장 작게 측정되어 최적 성장 조건임을 알 수 있었다. Hall 효과는 van der Paw방법에 의해 측정되었으며, 온도에 의존하는 운반자 농도와 이동도는 293K에서 각각 8.72$\times$$10^{23}$개/㎥, 3.42$\times$$10^{-2}$$m^2$/V.s였다. 상온에서 CuGaTe2 단결정 박막의 광흡수 특성으로부터 에너지 띠간격이 1.22 eV였다 Band edge에 해당하는 광전도도peak의 온도 의존성은 Varshni 관계식으로 설명되었으며, Varshni 관계식의 상수값은 Eg(0) = 1.3982 eV, $\alpha$= 4.27$\times$$10^{-4}$ eV/K, $\beta$= 265.5 K로 주어졌다. CuGaTe2 단결정 박막의 광전류 단파장대 봉우리들로부터 10K에서 측정된 $\Delta$cr (crystal Field splitting)은 0.0791eV, $\Delta$s.o (spin orbit coupling)는 0.2463eV였다. 10K에서 광발광 봉우리의 919.8nm (1.3479eV)는 free exciton(Ex), 954.5nm (1.2989eV)는 donor-bound exciton 인 I2(DO,X)와 959.5nm (1.2921eV)는 acceptor-bound exciton 인 I1(AO,X) 이고, 964.6nm(1.2853eV)는 donor-acceptor pair(DAP) 발광, 1341.9nm (0.9239eV)는 self activated(SA)에 기인하는 광발광 봉우리로 고찰되었다.

• Economic and Environmental Geology
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• v.25 no.1
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• pp.51-60
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• 1992

The pluton rocks in Kwangyang-Seungju area consist of two mica granite, hornblende diorite, Rimunri quartz diorite, grnodiorite porphyry and granophyre. The analysis of the geochronological data by the methods of K-Ar for the hornblende from Rimunri quartz diorite and hornblende diorite show that the ages are found to be $86{\pm}3.3$ Ma and $108{\pm}4$ Ma, respectively, and K-Ar age for chlorite from the altered two mica granite which intruded by the hornblende diorite of the Bonjeong mine shows $108{\pm}4$ Ma; K-Ar age for sericite from the greisenized hornblende diorite, which is closely associated with the Bonjeong ore deposits, is dated as $94.2{\pm}2.4$ Ma. They correspond to the igneous activity of the Bulgugsa Disturbance periods in the area. In chemical feature for oxides versus silica and AFM triagular diagrams of the pluton rocks in the study area, there is a suggestion of the possibility that these rock facies area a Calc-alkali series of differentiated products by low-pressure crystal fractionation processes in $SiO_2$-undersaturated suites. Compared with hornblende diorite, andesite and granodiorite porphyry, two mica granite, Rimunri quartz diorite and granophyre exhibit a wider range of normalized REE abundance and negative Eu anomalies. Such anomalies imply more extensive feldspar fractionation during crystallization. The Rimunri quartz diorite and hornblende diorite occurring in the margin of four mines(Bonjeong, Okdong, Soungchei and Saungyeul) of this area have high contents of As, Sb, Cu and Zn which have been shown as the best indicators in hypogene gold deposits and low contents of Ba, Cr served as more sensitive indicators. And the granitoids are regarded as the rocks associated with gold and sulfide mineralization of the area.

• Korean Journal of Organic Agriculture
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• v.7 no.1
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• pp.147-159
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• 1998

In order to study the effects of chemical fertilizer and organic fertilizer on the toxic mineral content in the absence or presence of the wood extraction, the lettuce an experiment of fatal 20 treatments was conducted far a peried of 10 weeks. The results obtained from the experiment are summarized as follows; 1. The mineral contents of the lettuce in the wood extraction-treated group and the wood extraction non-treated group showed no conspicious differenves. 2. These are no prominent differences in the mineal contents(Chromium, Nickel, Lead, and Aluminium) in the lettuce between the organic fertifized group and the lettuce raised in the chemical fertilized group. 3. Mercury was not detected in all samples of lettuces raised in all treatments.4. Cadmium contents in the lettuce samples were increased as the amount of organic fertilizer was increased from 25% to 100%.

• Journal of Korean Society on Water Environment
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• v.37 no.4
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• pp.306-314
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• 2021

The application of organic fertilizer could be accompanied by potential hazards to soil and humans due to trace metals. Livestock manure compost·liquefied fertilizer is a well-established approach for the stabilization of nutrients and the reduction of pathogens and odors in manures, which can be evaluated as compost·liquefied. In this study, the livestock manure compost·liquefied fertilizers produced at 333 liquid manure public resource centers and liquid fertilizer distribution centers were collected from May to December 2019. The nutrient content (nitrogen, phosphorus, and potassium), physicochemical properties, and heavy metal content were investigated. The livestock manure compost·liquefied fertilizer was measured using a mechanical maturity measurement device. The organic matter, arsenic, cadmium, mercury, lead, chromium, copper, nickel, zinc, E. coli (O157:H7), Salmonella, etc. of the livestock manure compost·liquefied fertilizers were analyzed. The average heavy metal content in the livestock manure compost·liquefied fertilizer was as follows: Cr 2.9 mg/kg (0.2~8.7 mg/kg), Cu 20.4 mg/kg (1.6~74.1 mg/kg), Ni 1.3 mg/kg (0.4~4.2 mg/kg), and Zn 79.8 mg/kg (3.0~340.7 mg/kg). Although large-scale organic fertilizer plants and resources recycling centers produce good organic (liquid) fertilizers with proper components, it is necessary to standardize livestock manure compost·liquefied fertilizer in order to facilitate efforts to turn livestock manure into useful resources.

• The Journal of the Petrological Society of Korea
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• v.1 no.1
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• pp.71-84
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• 1992

This paper reports the results about the petrography and mineral chemistry of 13 representative dredged basaltic rocks from the western Caroline Ridge (WCR) and Yap Trench-Arc system, and provides the chemical and tectonic informations based on the compositions of clinopyroxene phenocrysts. Compositions of olivine phenocrysts in some analyzed samples are Fo$_{86-80}$. Plagioclase phenocrysts have variable compositions ranging from An$_{90}$ to An$_{55}$. The compositions of clinopyroxene phenocrysts vary according to geological environments; titansalite in atoll and guyot of WCR, diopside-augite in trough and bank of WCR, and endiopside in Yap Trench-Arc system. Application of the discrimination schemes proposed by Leterrier et al. (1982) suggests: (1) the samples from atoll-guyot belong to within plate alkali basalt, implying that western CR could be the continuation of eastern CR formed by hot spot magmatism, (2) the samples from the Yap Trench-Arc system with no present-day magmatism clearly indicate the occurrence of orogenic tholeiites presumably related to early island arc magmatisms in this area, however, (3) the samples from the bank and trough do not provide definitive informations, which might indicate the complexity of their origins.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.2
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• pp.146-158
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• 2010

In order to evaluate the characteristics of sediments and pollution by organic matter and metallic elements in intertidal sediments along the southwestern coast of Korea, we measured various geochemical parameters, including the mean grain size (Mz), water content (WC), ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and metallic elements (Al, Fe, Cu, Pb, Zn, Cd, Cr, Mn, Hg, As), in intertidal surface sediments. The Mz of the surface sediments ranged from 2.1 to 8.3$\phi$, indicating that the surface sediments consist of various sedimentary facies, such as sand, slightly gravelly mud, sandy mud, and silt. The IL and COD in surface sediment ranged from 0.8 to 5.5% (mean $2.9\pm1.2%$) and from 3.9 to $13.8\;mgO_2/g{\cdot}dry$ (mean $8.5\pm2.6\;mgO_2/g{\cdot}dry$), respectively, which were lower than the values for surface sediment in areas near fish and shellfish farms or industrial complexes. No AVS was detected at any sampling station, despite various sedimentary facies. Most of metallic elements in surface sediments showed relatively good positive correlations with Mz and IL, which imply that the concentrations of metallic elements are mainly controlled by grain size and the organic matter content. The concentrations of metallic elements, except As, at some stations were considerably lower than those in the Sediment Quality Guideline (Effect Range Low, ERL) proposed by the National Oceanic and Atmospheric Administration (NOAA) in the United States. Similarly, the geoaccumulation index (Igeo) class indicated that pollution by metallic elements in intertidal surface sediment, except As, was moderate or non-existent. Our results imply that the intertidal surface sediments along the southwestern coast of Korea are not polluted by organic matter and metallic elements and are healthy for benthic organisms.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.167-170
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• 2004

The stochiometric mix of evaporating materials for the $CuGaT_2$ single crystal thin films was prepared from horizontal furnance. Using extrapolation method of X-ray diffraction patterns for the $CuGaTe_2$ polycrystal, it was found tetragonal structure whose lattice constant $a_0$ and $c_0$ were 6.025 ${\AA}$ and 11.931 ${\AA}$, respectively. To obtain the single crystal thin films, $CuGaTe_2$ mixed crystal was deposited on throughly etched semi-insulator GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were $670^{\circ}C$ and $410^{\circ}C$ respectively, and the thickness of the single crystal thin films is $2.1{\mu}m$. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). From the photocurrent spectrum by illumination of perpendicular light on the c - axis of the $CuGaTe_2$ single crystal thin film, we have found that the values of spin orbit coupling ${\Delta}s.o$ and the crystal field splitting ${\Delta}cr$ were $0.079\underline{1}eV$ and $0.246\underline{3}eV$ at 10 K, respectively. From the PL spectra at 10K, the peaks corresponding to free bound excitons and D-A pair and a broad emission band due to SA is identified. The binding energy of the free excitons are determined to be $0.047\underline{0}eV$ and the dissipation energy of the donor-bound exciton and acceptor-bound exciton to be $0.049\underline{0}eV$, $0.055\underline{8}eV$, respectively.

• Journal of Korea Foundry Society
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• v.20 no.5
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• pp.323-329
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• 2000

The HSS consists of hard carbide and matrix of martensite, and so its characteristics of wear resistance, fracture resistance, and surface roughness are good. This study was undertaken to investigate the influence of Nb and V and manufacturing conditions on microstructural behaviors and characteristics in the HSS cylindrical specimens(90 $mm^{O.D.}$ ${\times}$ 60 $mm^{I.D.}$ ${\times}$ 50 $mm^H$) manufactured using VCC(Vertical Centrifugal Casting). In the specimen of Fe-2C-6Cr-1.5W-3Mo-4V alloy, the amount of MC carbide was increased and $M_7C_3$ carbide was decreased with the increase of V and Nb contents. The primary VC carbide was formed and followed by the rod-type eutectic MC carbide was formed in the cell boundary in 9%V added specimen. MC carbide was increased, and $M_7C_3$ carbide was decreased with the addition of Nb content. In the specimen containing more than 3%Nb, primary NbC carbide was formed within the cell of matrix. With increase in rpm, cell and carbides became fine, and amount of carbide $M_7C_3$ was decreased due to increase in cooling rate.

• Nuclear Engineering and Technology
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• v.53 no.8
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• pp.2582-2590
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• 2021

The high-energy milling is one of the most extended techniques to produce Oxide dispersion strengthened (ODS) powder steels for nuclear applications. The consequences of the high energy mill process on the final powders can be measured by means of deformation level, size, morphology and alloying degree. In this work, an ODS ferritic steel, Fe-14Cr-5Al-3W-0.4Ti-0.25Y₂O₃-0.6Zr, was fabricated using two different mechanical alloying (MA) conditions (M_std and M_act) and subsequently consolidated by Spark Plasma Sintering (SPS). Milling conditions were set to evidence the effectivity of milling by changing the revolutions per minute (rpm) and dwell milling time. Differences on the particle size distribution as well as on the stored plastic deformation were observed, determining the consolidation ability of the material and the achieved microstructure. Since recrystallization depends on the plastic deformation degree, the composition of each particle and the promoted oxide dispersion, a dual grain size distribution was attained after SPS consolidation. M_act showed the highest areas of ultrafine regions when the material is consolidated at 1100 ℃. Microhardness and small punch tests were used to evaluate the material under room temperature and up to 500 ℃. The produced materials have attained remarkable mechanical properties under high temperature conditions.