• Nuclear Engineering and Technology
• /
• v.55 no.8
• /
• pp.2889-2896
• /
• 2023

The waste acceptance criteria for heavy metals in mixed waste should be developed by reflecting the leaching behaviors that could highly depend on the repository design and environment surrounding the waste. The current standards widely used to evaluate the leaching characteristics of heavy metals would not be appropriate for the silo-type repository since they are developed for landfills, which are more common than a silo-type repository. This research aimed to explore the leaching behaviors of cementitious waste with Pb, Cd, and Sb metallic and oxide powders in an environment simulating a silo-type radioactive waste repository. The Toxicity Characteristic Leaching Procedure (TCLP) and the ANS 16.1 standard were employed with standard and two modified solutions: concrete-saturated deionized and underground water. The compositions and elemental distribution of leachates and specimens were analyzed using an inductively coupled plasma optical emission spectrometer (ICP-OES) and energy-dispersive X-ray spectroscopy combined with scanning electron microscopy (SEM-EDS). Lead and antimony demonstrated high leaching levels in the modified leaching solutions, while cadmium exhibited minimal leaching behavior and remained mainly within the cement matrix. The results emphasize the significance of understanding heavy metals' leaching behavior in the repository's geochemical environment, which could accelerate or mitigate the reaction.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.33 no.1
• /
• pp.6-11
• /
• 2023

Objective: This study was conducted to identify the cause of suffocation accident. Methods: We analyzed the components of zinc concentrates by ICP-OES (inductively coupled plasma optical emission spectroscopy) and tested the oxygen consumption by zinc concentrates in a 13.2-liter closed chamber. Results: Zinc, sulfur and iron were the main components of the four types of zinc concentrates, and accounted for 76~89% by weight. Zinc concentrates (0.5 or 0.927 kg) depleted the oxygen concentration from 20.9% to 7.4~18.9% during seven days. The rate of oxygen consumption was in the range of 3.0~11.0 mM/day·kg-sample at 21~24℃ and around 95% of free air space within the closed chamber. Conclusion: Since zinc concentrate consumes oxygen in a confined space, measures should be taken to prevent suffocation accident (such as ventilation and monitoring of oxygen concentration).

• Journal of the Korean Applied Science and Technology
• /
• v.35 no.3
• /
• pp.816-825
• /
• 2018

Recently, it was emerged to need the necessity of LPG residues management due to the finding some substances such as rust. This study is performed to investigate the characteristics of LPG residues in the production and distribution stage of LPG. For the qualitative analysis of LPG residues, it was operated to be set up the analysis conditions(the flow rate, etc) of GC-MS and was performed to analyze the component of LPG residues. From the analysis result using GC-MS, it was shown that the component of LPG residues was turned out the plasticizer to be used in the rubber manufacturing process. The inorganic components of LPG residues were analyzed using ICP-OES. At the results of inorganic analysis, it was shown that the Si element was detected, which was presumably derived from defoamers used mainly in the LPG production. Also, the P and Zn element, which are estimated to be components of grease additives used for filling facilities, were also partially detected. No trace of rusting was detected in the LPG residues in the production and distribution stages analyzed in this study. But, as plasticizers and grease additives can affect to the LPG fuel system in vehicles, it will be necessary to use the proper quality of rubber and to expand the use of low boiling grease additives.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.12
• /
• pp.1873-1879
• /
• 2010

This study was conducted to estimate the heavy metal contents of vegetables available on the markets in Seoul area. Concentrations of mercury (Hg), lead (Pb), cadmium (Cd), arsenic (As), chrome (Cr), nickel (Ni), copper (Cu), and zinc (Zn) were measured in 300 samples using a mercury analyzer and inductively coupled plasma optical emission spectrometer (ICP-OES) after wet digestion. The average values of heavy metals in vegetables were as follows [mean (minimum~maximum), mg/kg]; Hg: 0.0005 (N.D~0.007), Pb: 0.011 (N.D~0.259), Cd: 0.012 (N.D~0.188), As: 0.002 (N.D~0.142), Cr: 0.100 (0.019~0.954), Ni: 0.093 (0.003~1.231), Cu: 1.098 (0.072~36.29), and Zn: 3.48 (0.485~21.31). The heavy metal contents of vegetables available on the markets in Seoul were almost the same as or lower than those reported in other studies. The weekly average intakes of mercury, lead and cadmium from vegetables take 0.44~7.71% of PTWI (Provisional Tolerable Weekly Intakes) that the FAO/WHO Joint Food Additive and Contaminants Committee sets for evaluation of food safety.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.8
• /
• pp.1134-1143
• /
• 2012

The aims of this study were to investigate some macrominerals (Na, Ca, P, K, Mg) in 207 beverages, 19 liquid teas, and 24 liquid coffees. The samples were digested by microwave and determinations of macrominerals were carried out by an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). The elements, listed in order of mean value of macromineral content, were potassium $208.4{\pm}298.2mg/L$ ($72.2{\pm}169.8mg/container$)> calcium $89.0{\pm}161.0mg/L$ ($26.0{\pm}57.7mg/container$)> sodium $71.2{\pm}75.0mg/L$ ($20.9{\pm}27.9mg/container$)> phosphorus $55.6{\pm}91.9mg/L$ ($17.9{\pm}33.8mg/container$)> magnesium $6.1{\pm}18.4mg/L$ ($2.4{\pm}10.1mg/container$). All 250 samples contained sodium and potassium, and the detection rate of calcium, phosphorus and magnesium was 88.4%, 93.2%, and 20.4%. The mean ratio of phosphorus to calcium in beverages, liquid teas, and liquid coffees was $4.2{\pm}16.0$ (ND~164.4), and sports drinks showed the highest mean ratio ($48.5{\pm}75.6$) significantly (p<0.05). In case of sodium, detected content exceeding labeling regulations (less then 120%) was observed in 12 samples (5.5%).

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.37 no.11
• /
• pp.18-24
• /
• 2000

(Ba,Sr)$TiO_3$ thin films have attracted great interest as new dielectric materials of capacitors for ultra-large-scale integrated dynamic random access memories (ULSI-DRAMs) such as 1 Gbit or 4 Gbit. In this study, inductively coupled $BCl_3/Cl_2/Ar$ plasmas was used to etch (Ba,Sr)$TiO_3$ thin films. RF power/dc bias voltage=600 W/-250 V and chamber pressure was 10 mTorr. The $Cl_2/(Cl_2+Ar)$ was fixed at 0.2 the (Ba,Sr)$TiO_3$ thin films were etched adding $BCl_3$. The highest (Ba,Sr)$TiO_3$ etch rate is $480{\AA}/min$ at 10 % $BCl_3$ to $Cl_2/Ar$. The change of Cl, B radical density measured by optical emission spectroscopy(OES) as a function of $BCl_3$ percentage in $Cl_2/Ar$. The highest Cl radical density was shown at the addition of 10% $BCl_3$ to $Cl_2/Ar$. To study on the surface reaction of (Ba, Sr)$TiO_3$ thin films was investigated by XPS analysis. Ion bombardment etching is necessary to break Ba-O bond and to remove $BaCl_2$. There is a little chemical reaction between Sr and Cl, but Sr is removed by physical sputtering. There is a chemical reaction between Ti and Cl, and $TiCl_4$ is removed with ease. The cross-sectional of (Ba,Sr)$TiO_3$ thin film was investigated by scanning electron microscopy (SEM), the etch slope is about 65~70$^{\circ}$.

• Journal of Food Hygiene and Safety
• /
• v.23 no.3
• /
• pp.239-247
• /
• 2008

Objective of this study was to investigate residual the levels of heavy metals in rice grain and soils of "Top-Rice" and common rice cultivation areas from 2005 to 2007. Soil and rice grain samples were taken from 33 "Top-rice" areas and neighboring paddies, and analyzed for the elements using ICP-OES and ICP-TOF-MS after acid digestion. A concentration of arsenic in paddy soil was 1.33 mg/kg which was below 1/5-1/11 fold of the threshold levels(concern: 4 mg/kg, action: 10 mg/kg), and paddy soil was 0.06 mg/kg of Cd(cadmium) being below 1/25-1/67 fold of the limits(concern: 1.5 mg/kg, action: 4 mg/kg). A level of Cu(copper) in paddy soil was 4.57 mg/kg which was below 1/11-1/27 fold of the threshold levels(concern: 50 mg/kg, action: 125 mg/kg), and Pb(lead) concentration in paddy soil was found to be a 4.68 mg/kg. In addition, Hg(mercury) concentration in paddy soil was to be a 0.03 mg/kg, which was below 1/131-1/328 fold of the threshold levels(concern: 4 mg/kg, action: 10 mg/kg). The average concentrations of As, Cd, Cu, Pb and Hg in the polished rice samples were 0.037, 0.043, 0.280, 0.048 and 0.002 mg/kg, respectively. These levels are lower than those of other countries in rice grains. Assuming the rice consumption of 205.7 g/day by total dietary supplements in Korea, the amount of total weekly metal intake of As, Cd, Cu, Pb and Hg by polished rice were estimated to be 0.0892, 1.035, 6.712, 1.161 and 0.054 ${\mu}g/kg$ body weigh/week, respectively. The PTWI(%) of As, Cd, Cu, Pb and Hg were 5.95(inorganic arsenic), 0.26(total arsenic), 14.79, 0.19, 4.65 and 1.07% estimated to be 0.0892, 1.035, 6.712, 1.161 and 0.054 ${\mu}g/kg$ body weigh/week, respectively. In conclusion, it was appeared that the heavy metals contamination in the brown and polished rice should not be worried in Korea.

• Korean Journal of Environment and Ecology
• /
• v.30 no.1
• /
• pp.98-103
• /
• 2016

Pyropia yezoensis were sampled from Jeonnam in Korea, Jiansu in China and Saga in Japan. Sampled P. yezoensis were analyzed proximate composition by Association official Analytical Chemists(AOAC) method, minerals by ICP-OES and amino acid by amino acid analyzer. Three areas resulted that contents of moisture and crude protein were $8.13{\pm}0.38%$ and $37.25{\pm}1.15%$, and crude lipid, ash and carbohydrate were $2.12{\pm}0.27%$, $7.41{\pm}0.36%$ and $45.06{\pm}1.30%$ respectively. In total minerals, Korea and China were $28300.19{\pm}76.39ppm$and $13945.63{\pm}7.73ppm$, and Japan was $12262.485{\pm}4.38ppm$. Amino acids, Korea and China were $265.28{\pm}0.38mg\;g^{-1}$ and $209.19{\pm}0.19mg\;g^{-1}$, and Japan was $157.61{\pm}0.43mg\;g^{-1}$. Therefore, those substance contents of P. yezoensis are significantly different between cultivation sites. The basic data may used to the environmental and nutritional study of P. yezoensis based on country sites.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.105-105
• /
• 2009

$ZrO_2$ is one of the most attractive high dielectric constant (high-k) materials. As integrated circuit device dimensions continue to be scaled down, high-k materials have been studied more to resolve the problems for replacing the EY31conventional $SiO_2$. $ZrO_2$ has many favorable properties as a high dielectric constant (k= 20~25), wide band gap (5~7 eV) as well as a close thermal expansion coefficient with Si that results in good thermal stability of the $ZrO_2/Si$ structure. In order to get fine-line patterns, plasma etching has been studied more in the fabrication of ultra large-scale integrated circuits. The relation between the etch characteristics of high-k dielectric materials and plasma properties is required to be studied more to match standard processing procedure with low damaged removal process. Due to the easy control of ion energy and flux, low ownership and simple structure of the inductively coupled plasma (ICP), we chose it for high-density plasma in our study. And the $BCl_3$ included in the gas due to the effective extraction of oxygen in the form of $BCl_xO_y$ compound In this study, the surface kinetic properties of $ZrO_2$ thin film was investigated in function of Ch addition to $BCl_3/Ar$ gas mixture ratio, RF power and DC-bias power based on substrate temperature. The figure 1 showed the etch rate of $ZrO_2$ thin film as function of gas mixing ratio of $Cl_2/BCl_3/Ar$ dependent on temperature. The chemical state of film was investigated using x-ray photoelectron spectroscopy (XPS). The characteristics of the plasma were estimated using optical emission spectroscopy (OES). Auger electron spectroscopy (AES) was used for elemental analysis of etched surface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.11a
• /
• pp.145-145
• /
• 2008

High-k materials have been paid much more attention for their characteristics with high permittivity to reduce the leakage current through the scaled gate oxide. Among the high-k materials, $ZrO_2$ is one of the most attractive ones combing such favorable properties as a high dielectric constant (k= 20 ~ 25), wide band gap (5 ~ 7 eV) as well as a close thermal expansion coefficient with Si that results in good thermal stability of the $ZrO_2$/Si structure. During the etching process, plasma etching has been widely used to define fine-line patterns, selectively remove materials over topography, planarize surfaces, and trip photoresist. About the high-k materials etching, the relation between the etch characteristics of high-k dielectric materials and plasma properties is required to be studied more to match standard processing procedure with low damaged removal process. Among several etching techniques, we chose the inductively coupled plasma (ICP) for high-density plasma, easy control of ion energy and flux, low ownership and simple structure. And the $BCl_3$ was included in the gas due to the effective extraction of oxygen in the form of $BCl_xO_y$ compounds. During the etching process, the wafer surface temperature is an important parameter, until now, there is less study on temperature parameter. In this study, the etch mechanism of $ZrO_2$ thin film was investigated in function of $Cl_2$ addition to $BCl_3$/Ar gas mixture ratio, RF power and DC-bias power based on substrate temperature increased from $10^{\circ}C$ to $80^{\circ}C$. The variations of relative volume densities for the particles were measured with optical emission spectroscopy (OES). The surface imagination was measured by scanning emission spectroscope (SEM). The chemical state of film was investigated using energy dispersive X-ray (EDX).