• Journal of Environmental Health Sciences
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• v.44 no.1
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• pp.55-62
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• 2018

Objectives: This study set out to measure the heavy metal concentrations in waste water produced in the casting pickling process at dental technical laboratories and examine the actual state of its treatment. Methods:The investigator measured the concentrations of each heavy metal at 55 dental technical laboratories using an inductively coupled plasma optical emission system. Results: The annual usage of electrolytes was under 10 L in 50 (90.9%), and was 10L or more in five (9.1%) laboratories. Among the laboratories, 15 (27.3%) commissioned the treatment of waste,12 (21.8%) treated the waste with general sewage,and 28 (50.9%) treated the waste in aseptic tank. The arithmetic $mean{\pm}standard$ deviation and the geometric mean of chrome(Cr) were $75.3{\pm}50.9$ and 58.3 mg/L; those of cobalt (Co) were $112.3{\pm}106.7$ and 66.1 mg/L; those of nickel (Ni) were $62.9{\pm}83.5$ and 8.9 mg/L; those of molybdenum (Mo) were $17.1{\pm}13.4$ and 12.0 mg/L; those of iron (Fe) were $31.5{\pm}44.1$ and 6.2 mg/L; those of lead (Pb) were $0.3{\pm}0.3$ and 0.3 mg/L; those of beryllium (Be) were $3.6{\pm}3.6$ and 2.0 mg/L. The hydrogen ion concentration was under pH 2 across all the samples. Conclusions: The findings show that the dental technical laboratories were not doing well with the separation, storage, collection, and treatment of the electrolytes they discarded, and that most of the electrolytes were introduced through the general sewage or aseptic tank. The causes of this include alack of perception among the practitioners at dental technical laboratories and contracted companies avoiding collection for economic reasons. There is a need for education to improve the perceptions of waste water treatment among the practitioners at dental technical laboratories. Environment-related departments should be stricter with legal applications in the central and local governments. It is also required to provide proper management of commissioned treatment.

• Analytical Science and Technology
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• v.15 no.6
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• pp.514-520
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• 2002

The electrothermal vaporization (ETV) hollow cathode glow discharge atomic emission spectrometer for analysis of liquid sample has been developed and characterized. This system has improved the sample introduction method of electrothermal vaporization and the hollow cathode glow discharge. The sample introduction method was possible to provide high analyte transport efficiency to the plasma by helix coil made of tungsten material. In addition, small volume samples (<$30{\mu}{\ell}$) could be used. The system has glow discharge cell with special design for improvement of precision. The effect of discharge parameters such as discharge power, gas flow rate has been studied to find optimum condition. The emitted light was effectively carried into detector by fiber optic cable in UV region. The calibration curve of Pb, Cd were obtained with 3 samples.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.10
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• pp.839-843
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• 2011

ZnO nanostructures were developed on a Si (100) substrate from powder mixture of ZnO and 5 mol% Pd (ZP-5) as reactants by ${\times}$ sccm oxygen pressures(x= 0, 10, 20, 40). DTA (differential thermal analysis) result shows the Pd(5 mol%)+ZnO mixtured powder(PZ-5) is easily evaporated than pure ZnO powder. The PZ-5 mixtured powder was characterized by DTA to determine the thermal decomposition which was found to be at $800^{\circ}C$, $1,100^{\circ}C$. Weight loss(%) and ICP (inductively coupled plasma) analysis reveal that Zn vaporization is decreased by increased oxygen pressures from the PZ-5 at $1,100^{\circ}C$ for 30 mins. Needle-like ZnO nanostructures array developed from 10 sccm oxygen pressure, was well aligned vertically on the Si substrate at $1,100^{\circ}C$ for 30 mins. The lengths of the Needle-like ZnO nanostructures is about 2 ${\mu}m$ with diameters of about 65 nm. The developed ZnO nanostructures exhibited growth direction along [001] with defect-free high crystallinity. It is considered that Zn vaporization is responsible for the growth of Needle-like ZnO nanostructures by controlling the oxygen pressures. The photoluminescence spectra of ZnO nanostructures exhibited stronger 376.7 nm NBE (near band-edge emission) peak and 529.3 nm DLE (deep level energy) peak.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.3
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• pp.344-351
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• 2021

The purpose of this study was to compare surface hardness between titanium-nitride coated crowns (TiNCs) and stainless steel crowns (SSCs), and to evaluate the corrosion resistance and color sustainability of TiNCs. Ten TiNCs and 10 SSCs were used for the hardness test. Measurement was performed 30 times for each type of crowns, and the mean values were compared. Metallic raw material plates (before being processed into crowns) of TiNCs and SSCs were prepared for the corrosion resistance test. The total amounts of metal ion releases in the test solution were detected by inductively coupled plasma-optical emission spectrometry. Five TiNCs were subjected to the color sustainability test by applying repetitive brushing forces. The mean hardness values of TiNC group and SSC group were 395.53 ± 105.90 Hv and 278.70 ± 31.45 Hv respectively. Hardness of TiNCs were significantly higher than that of SSCs. The total amounts of metal ion releases from the materials of TiNCs and SSCs satisfied the criterion in International Organization for Standardization 22674. The results mean that TiNCs and SSCs were not harmful in an acidic environment. The golden coating was stable against the repetitive physical stimulations for a given period time.

• Resources Recycling
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• v.30 no.5
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• pp.38-48
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• 2021

In this study, we determine the optimal process conditions for selectively recovering Si from a solar cell surface by removal of impurities (Al, Zn, Ag, etc.). To selectively recover Si from solar cells, leaching is performed using HCl solution and an ultrasonic cleaner. After leaching, the solar cells are washed using distilled water and dried in an oven. Decompression filtration is performed on the HCl solution, and ICP-OES (Inductively Coupled Plasma Optical Emission spectroscopy) full scan analysis is performed on the filtered solution. Furthermore, XRD (X-ray powder diffraction), XRF (X-ray fluorescence), and ICP-OES are performed on the dried solar cells after crushing, and the purity and recovery rate of Si are obtained. In this experiment, the concentration of acid solution, reaction temperature, reaction time, and ultrasonic intensity are considered as variables. The results show that the optimal process conditions for the selective recovery of Si from the solar cells are as follows: the concentration of acid solution = 3 M HCl, reaction temperature = 60℃, reaction time = 120 min, and ultrasonic intensity = 150 W. Further, the Si purity and recovery rate are 99.85 and 99.24%, respectively.

• Journal of Nutrition and Health
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• v.53 no.6
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• pp.663-675
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• 2020

Purpose: The aim of this study was to measure the sodium content of the solid and liquid components of soup-based dishes (SBD) including Korean soup, stew, noodle/dumplings, and watery kimchi and to compare the sodium content in the dishes from home, schools, and restaurants in Seoul. Methods: The dishes were divided into 3 groups, namely home, restaurant and school food. We separated the dishes into solid and liquid to measure the weight, salinity, and sodium content. The sodium content of the dishes was analyzed using inductively coupled plasma atomic emission spectrometry. Results: The proportion of sodium content in the liquid component of SBD were 65.2%-66.7% in soup, 49.8%-61.2% in stew, 48.7%-56.7% in noodle/dumpling, and 43.7%-73.2% in watery kimchi. The sodium content per 100 g of the whole dishes of the same kind from the schools was significantly lower than that from the restaurants and home. However, there was no significant difference in sodium content per 100 g of whole dishes between the restaurants and home. The sodium content per 100 g of liquid in the same kind of dishes from the schools was significantly lower than those from the restaurants and home, and that from home was significantly lower than from the restaurants. Conclusion: The sodium content of the liquid in SBD accounted for at least about half of the total sodium content of the whole dishes. It is important to establish a separate database with the sodium content in the solid and liquid portions of SBD and to evaluate how much liquid and/or solid would be consumed to estimate individual sodium intake more accurately. Also, it should be noted that the sodium content varies with the origin of the dishes, whether dishes were from home, restaurants, or schools.

• Journal of the Korean GEO-environmental Society
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• v.12 no.7
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• pp.23-29
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• 2011

The oxidation slag has been widely used in civil engineering project, whereas the reduced slag from electric furnace has yet to be applied. Consequently in order to find out the recycling method in civil engineering field, the mineral compositions of the reduced slag were analyzed and some tests on water quality were performed to estimate the potential release of toxic compounds. Slag-soil mixtures of 0, 10, 20 and 30%(dry weight) soil were prepared in lysimeter columns and the effluents were collected with the period of one, two and four week options in closed system, respectively. The result from qualitative and quantitative analysis using X-ray Diffraction(XRD) and X-ray Fluorescence(XRF) indicates that the main mineral of the reduced slag is $Ca_2(SiO_4)$, a kind of calcium silicate. Also, the leaching medium analyzed by Inductively Coupled Plasma Optical Emission Spectroscopy(ICP-OES) showed that main heavy metals such as Al, Fe and Mn are included in the reduced slag due to the effect of steel production process. It can be seen that the leachate does not violate the regulation guide line of waste material of heavy metal. Also the pH levels were increased from pH 6.9 for 0% soil to pH 10 for 30% soil. However the influence on leachate circulation period of one through four weeks was negligible.

• Korean Journal of Metals and Materials
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• v.46 no.11
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• pp.762-769
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• 2008

Hydrogenated amorphous silicon(a-Si : H) layers, 120 nm and 50 nm in thickness, were deposited on 200 $nm-SiO_2$/single-Si substrates by inductively coupled plasma chemical vapor deposition(ICP-CVD). Subsequently, 30 nm-Ni layers were deposited by E-beam evaporation. Finally, 30 nm-Ni/120 nm a-Si : H/200 $nm-SiO_2$/single-Si and 30 nm-Ni/50 nm a-Si:H/200 $nm-SiO_2$/single-Si were prepared. The prepared samples were annealed by rapid thermal annealing(RTA) from $200^{\circ}C$ to $500^{\circ}C$ in $50^{\circ}C$ increments for 30 minute. A four-point tester, high resolution X-ray diffraction(HRXRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and scanning probe microscopy(SPM) were used to examine the sheet resistance, phase transformation, in-plane microstructure, cross-sectional microstructure, and surface roughness, respectively. The nickel silicide on the 120 nm a-Si:H substrate showed high sheet resistance($470{\Omega}/{\Box}$) at T(temperature) < $450^{\circ}C$ and low sheet resistance ($70{\Omega}/{\Box}$) at T > $450^{\circ}C$. The high and low resistive regions contained ${\zeta}-Ni_2Si$ and NiSi, respectively. In case of microstructure showed mixed phase of nickel silicide and a-Si:H on the residual a-Si:H layer at T < $450^{\circ}C$ but no mixed phase and a residual a-Si:H layer at T > $450^{\circ}C$. The surface roughness matched the phase transformation according to the silicidation temperature. The nickel silicide on the 50 nm a-Si:H substrate had high sheet resistance(${\sim}1k{\Omega}/{\Box}$) at T < $400^{\circ}C$ and low sheet resistance ($100{\Omega}/{\Box}$) at T > $400^{\circ}C$. This was attributed to the formation of ${\delta}-Ni_2Si$ at T > $400^{\circ}C$ regardless of the siliciation temperature. An examination of the microstructure showed a region of nickel silicide at T < $400^{\circ}C$ that consisted of a mixed phase of nickel silicide and a-Si:H without a residual a-Si:H layer. The region at T > $400^{\circ}C$ showed crystalline nickel silicide without a mixed phase. The surface roughness remained constant regardless of the silicidation temperature. Our results suggest that a 50 nm a-Si:H nickel silicide layer is advantageous of the active layer of a thin film transistor(TFT) when applying a nano-thick layer with a constant sheet resistance, surface roughness, and ${\delta}-Ni_2Si$ temperatures > $400^{\circ}C$.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.1
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• pp.15-21
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• 2022

The purpose of our study was to investigate the migration level of lead (Pb), cadmium (Cd), and barium (Ba) from glassware into a food simulant and to evaluate the exposure of each element. The test articles were glassware, including tableware, pots, and other containers. Pb, Cd, and Ba were analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The analytical performance of the method was validated in terms of its linearity, limit of detection (LOD), limit of quantification (LOQ), recovery, precision, and uncertainty. The monitoring was performed for 110 samples such as glass cups, containers, pots, and bottles. a food simulant. Migration test was conducted at 25? for 24 hours in a dark place using 4% acetic acid as a food simulant. Based on the data; exposure assessment was carried out to compare the estimated daily intake (EDI) to the human safety criteria. The risk levels of Pb and Ba determined in this study were approximately 1.9% and 0.3% of the provisional tolerable weekly intake (PTWI) and tolerable daily intake (TDI) value, respectively, thereby indicating a low exposure to the population.

• Journal of Ginseng Research
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• v.46 no.2
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• pp.235-247
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• 2022

Background: Ginsenoside Rg3 is one of the main active ingredients in ginseng. Here, we aimed to confirm its protective effect on the heart function in transverse aortic coarctation (TAC)-induced heart failure mice and explore the potential molecular mechanisms involved. Methods: The effects of ginsenoside Rg3 on heart and mitochondrial function were investigated by treating TAC-induced heart failure in mice. The mechanism of ginsenoside Rg3 for improving heart and mitochondrial function in mice with heart failure was predicted through integrative analysis of the proteome and plasma metabolome. Glucose uptake and myocardial insulin sensitivity were evaluated using micro-positron emission tomography. The effect of ginsenoside Rg3 on myocardial insulin sensitivity was clarified by combining in vivo animal experiments and in vitro cell experiments. Results: Treatment of TAC-induced mouse models with ginsenoside Rg3 significantly improved heart function and protected mitochondrial structure and function. Fusion of metabolomics, proteomics, and targeted metabolomics data showed that Rg3 regulated the glycolysis process, and Rg3 not only regulated glucose uptake but also improve myocardial insulin resistance. The molecular mechanism of ginsenoside Rg3 regulation of glucose metabolism was determined by exploring the interaction pathways of AMPK, insulin resistance, and glucose metabolism. The effect of ginsenoside Rg3 on the promotion of glucose uptake in IR-H9c2 cells by AMPK activation was dependent on the insulin signaling pathway. Conclusions: Ginsenoside Rg3 modulates glucose metabolism and significantly ameliorates insulin resistance through activation of the AMPK pathway.