• Journal of Preventive Medicine and Public Health
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• v.27 no.1 s.45
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• pp.25-43
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• 1994

To estimate the factors to the inclination of the criminal violence, the content of trace minerals and toxic metals in the scalp hair were measured during the period from May 1992 to October 1992. One hundred eleven violent and 89 nonviolent criminal inmates of Taegu Correctional Institute were selected. The inmates of violent criminals were imprisoned by murder, robber, rape, injury and violent acts. Those of nonviolent criminals were swindle, larceny, and adultery and had no history of institutional violence. The contents of two toxic metals (cadmium, lead) and five trace minerals (Cu, Fe, Zn, Mg, Na) were determined by an atomic absorption spectrophotometer (IL. 551). The contents of cadmium and lead in hair of violent criminals were significantly higher as $0.56{\pm}0.14ppm,\;11.53{\pm}3.32ppm$, respectively, than $0.42{\pm}0.20ppm,\;9.63{\pm}4.31ppm$ of nonviolent group (p<0.01). But the level of copper was significantly lower than nonviolent group (p<0.05). The factors that had a significant correlation with the inclination of violence in multiple logistic regression analysis were cadmium (odds ratio=98.09), unmarried (odds ratio=0.39), many times of criminal history(odds ratio=1.57) and residence of rural area (odds ratio=0.44). The results suggest that the sub-toxic contents of cadmium and lead in the hair may be of potential effect on behavior, and the mineral analysis may be an important adjunctive diagnostic procedure. Further studies into this problem are necessary.

• Korean Journal of Environmental Agriculture
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• v.19 no.5
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• pp.401-418
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• 2000

1. Production of the artificial zeolite from coal ash Coal fly ash is mainly composed of several oxides including $SiO_2$ and $Al_2O_3$ derived from inorganic compounds remained after burning. As minor components, $Fe_2O_3$ and oxides of Mg, Ca, P, Ti (trace) are also contained in the ash. These components are presented as glass form resulting from fusion in the process of the combustion of coal. In other word, coal ash may refer to a kind of aluminosilicate glass that is known to easily change to zeolite-like materials by hydrothermal reaction. Lots of hot seawater is disposing near thermal power plants after cooling turbine generator periodically. Using seawater in the hydrothermal reaction caused to produce low price artificial zeolite by reduction of sodium hydroxide consumption, heating energy and water cost. As coal ash were reacted hydrothermally, peaks of quartz and mullite in the ash were weakened and disappeared, and new Na-Pl peaks were appeared strengthily. Si-O-Si bonding of the bituminous coal ash was changed to Si-O-Al (and $Fe^{3+}$) bonding by the reaction. Therefore the produced Na-Pl type zeolite had high CEC of 276.7 $cmol^+{\cdot}kg^{-1}$ and well developed molecular sieve structure with low concentration of heavy metals. 2. Utilization of the artificial zeolite in agro-environment The artificial zeolite(1g) could remove 123.5 mg of zinc, 164.7 mg copper, 184.4 mg cadmium and 350.6 mg lead in the synthetic wastewater. The removability is higher 2.8 times in zinc, 3.3 times in copper, 4.7 times in cadmium and 4.8 times in lead than natural zeolite and charcoal powder. When the heavy metals were treated at the ratio of 150 $kg{\cdot}ha^{-1}$ to the rice plant, various growth inhibition were observed; brownish discoloration and death of leaf sheath, growth inhibition in culm length, number of panicles and grains, grain ripening and rice yield. But these growth inhibition was greatly alleviated by the application of artificial zeolite, therefore, rice yield increased $1.1{\sim}3.2$ times according to the metal kind. In addition, the concentration of heavy metals in the brown rice also lowered by $27{\sim}75%$. Artificial Granular Zeolites (AGZ) was developed for the purification of wastewater. Canon exchange capacity was 126.8 $cmol^+{\cdot}kg^{-1}$. AGZ had Na-Pl peaks mainly with some minor $C_3S$ peaks in X-ray diffractogram. In addition, AGZs had various pore structure that may be adhere the suspended solid and offer microbiological niche to decompose organic pollutants. AGZ could remove ammonium, orthophosphate and heavy metals simultaneously. Mixing ratio of artificial zeolite in AGZs was related positively with removal efficiency of $NH_4\;^+$ and negatively with that of $PO_4\;^{3-}$. Root growth of rice seedling was inhibited severely in the mine wastewater because of strong acidity and high concentration of heavy metals. As AGZ(1 kg) stayed in the wastewater(100L) for 4days, water quality turned into safely for agricultural usage and rice seedlings grew normally.

• Korean Journal of Heritage: History & Science
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• v.43 no.3
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• pp.102-121
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• 2010

Three bronze bells excavated from the Hoeamsa temple site were investigated for their microstructures and chemical compositions in an effort to understand the technology applied in fabrication, which may represent the related industry established in the early Joseon period. The result shows that the bells were cast from alloys of approximately 85% copper-8% tin-7% lead. The chemical analysis for ten trace elements shows that they were all kept below 0.3 weight %, suggesting that the alloys were made of relatively well-refined copper, tin and lead. The presence of sulfur and iron indicates that chalcopyrite or chalcocite may have been used in the smelting of copper. Evidence has been found that the bells were cast by pouring the liquid metal from the top of the sand molds that were set up in an upright position. No additional treatments, thermal or mechanical, other than a little grinding were applied upon the completion of casting. After the shaping process, a balancing plate was attached to the top of the bell using a steel connection ring. The connection assembly was then fixed to the main body by using molten bronze as a solder. The surface inscription was found carved using different techniques. The differences in the order of strokes and the calligraphic style indicate that the carving was carried out by more than one master. In the absence of documentary evidence on past bronze technology, the present bronze bells with known chronology, provenance and the main agent of production, prove to be a rare and valuable archaeological material for the understanding of the related technology in use in the early Joseon period.

• Korean Journal of Heritage: History & Science
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• v.53 no.1
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• pp.150-167
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• 2020

The purpose of this paper is to share the status and introduce a scientific analysis of the GeumguJagi (gilt-silver overlay porcelain, 金釦瓷器) excavated from Seongneung (石陵). This analysis aimed to highlight the GeumguJagi excavated from the Royal Tombs of Goryeo with a clear lower year (1237) and to aid research into the GeumguJagi. In 2001, the National Institute of Cultural Heritage excavated and investigated Seongneung in Heejong (熙宗). Various artifacts such as celadon, gold, bronze, and iron products were collected from the chambers inside of the tomb. There were a total of 160 celadon items including bowls, dishes, glasses, and saucers. Of those, there were 58 celadon items (including fragments) with metal frames on the openings. These consisted of bowls, plates, lids, and saucers. Until recently, in various exhibitions and papers, only one GeumguJagi was known to have been excavated from Seongneung, which was a . However, the survey identified a number of further GeumguJagis. It had been understood from inherited and excavated products that the materials used for ornaments were restricted to high-quality celadon. However, this study confirmed that the excavation of Seongneung demonstrated the use of various other materials for different models and qualities of GeumguJagis. It can be said that it is characteristic that various models and quality are confirmed together through the excavation of Seongneung. A scientific analysis was carried out that selected 12 of 58 products excavated from Seongneung. Results showed that the main component used for Geumgu ornaments was tin (Sn), and trace amounts of copper (Cu) and lead (Pb) were also commonly identified. When analyzing the material used to affix the metal fittings, this was found to be glue (膠) made from animal skins, muscle, and bones. This pattern matches that of the GeumguJagi excavated from Paju Hyeeumwonji, and the reason for this could be assumed on the basis of the contents of the 『Cheongonggaemul (天工開物)』 written by Song Ongsung (宋應星) during the Ming Dynasty. At that time, metals such as tin and copper would have been difficult to obtain. 『Xuānhwafengshi Gaolitujing (宣和奉使高麗圖經)』 shows that the use of metal was limited to certain classes; thus, the use of the GeumguJagi seems to have been centered around the royal family.

• Journal of Mushroom
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• v.18 no.4
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• pp.387-392
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• 2020

Eight dried ear mushroom products (three domestic and five Chinese products) distributed in Korea were analyzed for 321 residual pesticides, 7 heavy metals, and 3 types of radioactivity. Residual pesticides in the domestic products were not detected. However, chlorpyrifos, isoprocarb, mepiquat chloride, and carbendazim were detected in four Chinese products, all of which were below the allowable residual limit. Among the detected pesticide ingredients, only the residue for mepiquat chloride has been established to be present in ear mushrooms. In the heavy metal test, trace amounts of heavy metals were detected in all samples. However, none of the samples exceeded the allowable residual limits, except for one domestic sample that exceeded the standard value of 0.3 mg/kg for lead. Radioactivity tests confirmed that levels were below the minimal detectable activity value in all samples.

• Korean Journal of Materials Research
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• v.32 no.1
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• pp.9-13
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• 2022

Bullets flying with a light from the back are called "tracers". Tracers are ignited by the combustion gas of the propellant and emit bright light that allows the shooter to visually trace the flight path. Therefore, tracers mark the firing point for allies to assist shooters to hit target quickly and accurately. Conventional tracers are constructed with a mixture of an oxidizing agent, raw metal, and organic fuel. Upon ignition, the inside of the gun can be easily contaminated by the by-products, which can lead to firearm failure during long-term shooting. Moreover, there is a fire risk such as forest fires due to residual flames at impact site. Therefore, it is necessary to develop non-combustion type luminous material; however, this material must still use the heat generated from the propellant, so-called "thermoluminescence (TL)". This study aims to compare the TL emission of Dy³⁺, La³⁺ and Ho³⁺ doped MgB₄O₇ phosphors prepared by solid state reaction. The crystal structures of samples were determined by X-ray diffraction and matched with the standard pattern of MgB₄O₇. Luminescence of various doses (200 ~ 15,000 Gy) of gamma irradiated Dy³⁺, La³⁺ and Ho³⁺ (at different concentrations of 5, 10, 15 and 20 %) doped MgB₄O₇ were recorded using a luminance/color meter. The intensity of TL yellowish (CIE x = 0.401 ~ 0.486, y = 0.410 ~ 0.488) emission became stronger as the temperature increased and the total gamma-ray dose increased.

• Journal of Food Hygiene and Safety
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• v.25 no.4
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• pp.395-401
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• 2010

This research was carried out as a survey on the contents of Lead (Pb) and Cadmium (Cd) in 5 type agricultural products unestablished safety guideline in Korea. The average levels of Pb: onion 0.010 mg/kg, cucumber 0.018 mg/kg, garlic 0.012 mg/kg, green pepper 0.027 mg/kg, sesame 0.029 mg/kg. The average levels of Cd: onion 0.006 mg/kg, cucumber 0.002 mg/kg, garlic 0.008 mg/kg, green pepper 0.011 mg/kg, sesame 0.024 mg/kg. The present result of this study showed that Pb and Cd contents in the whole samples were less than the maximum residual levels of the codex standard. The levels of exposure assessment for Pb and Cd by intake from vegetables and sesame were merely at $1.3{\times}10^{-4}$(mean) ~ $5.1{\times}10^{-4}$($95^{th}$ percentiles) ${\mu}$g/kg bw/day for Pb, $7.5{\times}10^{-5}$(mean) ~ $3.6{\times}10^{-4}$($95^{th}$ percentiles) ${\mu$}g/kg bw/day for Cd. The data from this research will be valuable source for database construction for science-based safety control and management for the trace metal contamination in food including agricultural products.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.3
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• pp.175-182
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• 2022

Heavy metals can be intentionally or unintentionally introduced into plastic food utensils, containers, and packaging (PFUCP) as additives or contaminants, which can be ingested with food by humans. Here, seven-heavy metals (lead, cadmium, nickel, chromium, antimony, copper, and manganese) with toxicity concerns were selected, and risk assessment was done by establishing their migration from 137 PFUCP products made of 16 materials distributed in Korea. Migration of heavy metals was examined by applying 4% acetic acid as a food simulant (70℃, 30 minutes) to the PFUCP products. Inductively coupled plasma mass spectrometry (ICP-MS) was employed for the analysis of migrated heavy metals, and the reliability of quantitative results was confirmed by checking linearity, LOD, LOQ, recovery, precision, and expanded uncertainty. As a result of monitoring, heavy metals were detected at a level of non-detection to 8.76 ± 11.87 ㎍/L and most of the heavy metals investigated were only detected at trace amounts of less than 1 ㎍/L on average. However, antimony migrated from PET products was significantly higher than other groups. Risk assessment revealed that all the heavy metals investigated were safe with a margin of exposure above 311. Collectively, we demonstrated that heavy metals migrated from PFUCP products distributed in Korea appear to be within the safe range.