• 한국공작기계학회논문집
• /
• 제13권3호
• /
• pp.119-125
• /
• 2004

Generally, it is used the compensation spring to compensate the inaccuracy of screen image induced by thermal deformation in CRT monitor. Its mechanism is bi-metallic system made of heterogeneous metals and these is bonded by laser welding. But laser welding induces the non-uniform temperature distribution and locally residual stress is yielded by these temperature deviation. This paper studies residual stress of laser weldment using FEA and hole drilling method. The results are followed. In the case of heterogeneous materials weldment, higher residual stress induced in the weldment region of SUS 304 which have larger CTE than Ni 36 and residual stress on the middle of specimen is higher by 10.9% than that of its surface Measured residual stress of SUS 304 yield 481MPa and that of Ni 36 is 140.5MPa in the vicinity of the welding region. And the residual distribution is very similar in comparison with FEA result.

• 한국잠사곤충학회지
• /
• 제50권2호
• /
• pp.48-52
• /
• 2012

비섬유용 소재로 활용될 누에고치의 중금속 함량 및 농약잔류량을 조사하였다. 농가에서 생산하는 누에고치에서 상견비율은 89.1%, 전견중은 2.11 g, 견층중은 0.4670 g으로 나타나 견층비율 22.13%인 것으로 나타났다. 누에고치의 일반 성분을 분석한 결과 조단백질은 93 ~ 94%, 수분은 5 ~ 6%, 조회분은 0.3 ~ 0.4%, 그리고 조지방은 0.4 ~ 0.5%로 나왔다. 누에고치의 중금속 분석 결과 비소, 납, 카드뮴 등은 검출되지 않았으나, 아연이 3.99 mg/kg, 수은은 0.317 mg/kg 포함되어 있었다. 농가에서 사용하는 농약 성분인 디클로르보스와 파라콰트가 검출되지 않아 식품, 화장품, 의료용 소재 등 비섬유용 소재로 활용이 가능할 것으로 사료된다.

• 동의생리병리학회지
• /
• 제25권3호
• /
• pp.489-495
• /
• 2011

The purpose of this study was to analyze harmful heavy metals, sulfur dioxide and residual pesticides in 30 kinds of oriental medical materials. This study was carried out on 30 samples of oriental medical materials. The examination's methods fallow the guideline of Food and Drug Administration. Inductively Coupled Plasma Mass Spectrometer (ICP-OES) was used to analyze lead, arsenic, cadmium. Mercury was analyzed by amalgamation method. A modified Monier-Williams method was used to analyze sulfur dioxide. The Gas Chromatography / Electron Capture Detector (GC/ECD) was used to analyze residual pesticides. Most of the results were within normal limits at baseline. but Cadmium was detected 0.523 mg/kg more than 0.3 mg/kg in Cinnamomi ramulus and Endosulfan was detected 11.595 mg/kg more than 0.2 mg/kg in Alismatis rhizoma. We needs to keep the quality of herbal medicines assessing and controling for safety of herbal medicines.

• 한국버섯학회지
• /
• 제15권4호
• /
• pp.202-205
• /
• 2017

국내 안전 버섯생산을 위해서 수입된 표고균이 접종된 표고배지에서 중금속과 잔류농약의 존재 위험성을 두고 우려가 있어 왔다. 버섯의 안전 생산을 위해서는 우려되는 위험성에 대해 건전한 논의를 위한 기초 자료가 필요하다. 이에따라 본 연구에서는 2013년과 2015년 사이 중국 6개 지역에서 수입된 표고균이 접종된 톱밥배지에서 중금속과 잔류농약 존재여부를 알고자 분석을 수행하였다. 납, 비소, 크롬, 수은, 카드뮴 중에서 비소, 크롬, 수은은 검출되지 않았다. 납은 길림, 산동, 텐진, 요녕 지역에서 수입된 표고톱밥배지에서 검출되었으며 검출수준은 1.7 에서 3.2 mg/kg 이었다. 카드뮴은 산동과 요녕 지역에서 검출되었고 검출수준은 0.028 to 0.037 mg/kg 이었다. 잔류농약은 모든 시료에서 불검출되었다.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
• /
• pp.11-14
• /
• 2001

In this study, the relationship between metals (Cu, Cr, Cd, Zn. Pb, and Fe) 5 fractions and toxicity of soil samples from various contaminated sites in Korea were investigated. Metal toxicity of soils was tested using MetPLATE$^{TM}$ test kit, which is known as metal sensitive and organic insensitive. Significant amount of Fe was found in soils, and metal contents were in the order of Fe>Zn>Pb>Cu>Cr>Cd. Metal levels in organic fraction were rather high for all metals except Fe, and quite high percentages (35~79%) for residual fraction were observed for all metals. There were no significant relationships between the content of each metal fraction and toxicity which showed regression $R^2$in the range of 0.0003~0.414. However, correlation between toxicity and total metal contents showed regression coefficient $R^2$= 0.72. These results showed that the risk evaluation of metals in contaminated sites should be difficult to assess only by the contents of metal distribution because of the complexity of mixture of various metals.s.

• 동의생리병리학회지
• /
• 제22권4호
• /
• pp.948-953
• /
• 2008

The purpose of this study was to analyze harmful heavy metals, sulfur dioxide and residual pesticides in 27 kinds of oriental medical materials. This study was carried out on 27 samples of oriental medical materials. The GC-ECD(Varian, CP-3800) was used to analyze residual pesticides. ICP-OES(Varian, Vista-MPX) was used to analyze lead, arsenic, cadmium. Mercury was analyzed by amalgamation method. A modified Monier-Williams method was used to analyze sulfur dioxide. Arsenic was detected less than 3(mg/kg) in 14 samples and was not detected 13 samples. Lead was detected less than 5(mg/kg) in 15 samples and was not detected 12 samples. Mercury was detected less than 0.2(mg/kg) in 15 samples and was not detected 12 samples. Cadmium was detected more than 0.3(mg/kg) in 3 samples was detected less than 0.3(mg/kg) in 16 samples and was not detected 11 samples. A few residual pesticides was detected, but all residual pesticides was safe. Sulfur dioxide was detected in all samples, but all residual sulfur dioxide was safe.

• 한국환경과학회지
• /
• 제12권2호
• /
• pp.227-236
• /
• 2003

Electrokinetic remediation technique offers the opportunity to extract heavy metals from soils with high plasticity. The experiment demonstrated the applicability of electrokinetic remediation on metal-mining deposit and the decision of the enhancement method for four kinds of bench-scale studies. According to the sequential extraction of heavy metals in the "I" mining deposit, Pb and Cu were mostly associated with residual fraction and Zn and Cd were associated with water soluble and residual fraction. Therefore, removable fractions by electrokinetic technology was determined by the sum of the fraction of water soluble and exchangeable, which is Cu : 19.53%, Pb : 1.42%, Cd : 52.82%, Zn : 57.28%, respectively. When considering electrical potential, volume of effluent, soil pH, and eliminated rate of contaminant, results determined by sum of each weight were Citric aic+SDS (13) > 0.1N $HNO_3$ (10) > HAc (8) > DDW (4). Therefore, citric acid and SDS mixed solution was determined the best enhancing agent for the remediation of metal mining deposit.g deposit.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
• /
• pp.249-251
• /
• 2001

A novel technology for recycling valuable metals contained in waste dry-battery by vacuum metallurgy was devised by theoretical analysis. On the condition of the total chamber pressure of 1.013$\upsilon$10$^1$Pa, Hg, Cd and Zn are distilled in the temperature range of 773~973K, Pb is volatilized in the range of 1173~1273K while Mn, Cu, Fe and C are remained in residual. MnO$_2$and ZnO are reduced by carbon in waste dry-battery in 773~1273K. Pure metals including Zn, Cd, Hg and Pb can be recovered respectively from their mixed vapor by fractional condensation. Metal Cu and MnO$_2$can be obtained from the residual by hydrometallguical method. The technology can eliminate the pollution of Cd, Hg and Pb to environment.

• 한국생산제조학회지
• /
• 제5권4호
• /
• pp.53-62
• /
• 1996

Recently, ceramic / metal bonded joints have led to inccreasing use of structural materials such as automobile, heat engine in various industries. In this paper, a method to analyze an interface crack under both residual stresses and applied loading was proposed. and some results of boundary element method(BEM) analysis Were presented, Fracture thoughness tests of ceramic/metals bonded joints with an interface crack Were carried out, and the stress intensity factors of these joints Ware analyzed by BEM. Also crack propagtion direction was simulated numerically by using BEM. Crack propagation angle was able to easily determine based on the maximum stress concept. The prediction of fracture strength by the fracture thoughness of the ceramics/metals bonded joints was proposed.

• 한국환경과학회지
• /
• 제15권2호
• /
• pp.163-167
• /
• 2006

To obtain the safety evaluation of the ginseng, residues of heavy metals in culture environment of ginseng on Punggi and Sangju, Kyeongbuk are surveyed. The concentration for component of ginseng on Punggi and Sangju were 14.12mg/kg and 15.74mg/kg, respectively. The concentration for general component such as crude fiber, ash, crude lipid, crude protein, carbohydrate, of ginseng were coincided between Punggi and Sangju. The concentration for As, Pb, Cd, and Hg in soil on Punggi were 14.24 ppb, 43.13 ppb, 8.73 ppb and 0.82 ppb, respectively. The concentration for As, Pb, Cd, and Hg in soil on Sangju were 19.20 ppb, 54.82 ppb, 15.90 ppb and 1.04, respectively. Residual heavy metals are not polluted in the soil with culture ginseng on Punggi and Sangju. The concentration for As, Pb, Cd, and Hg with ginseng on Punggi were 29.30ppb, 21.78 ppb, 1.32 ppb and 2.72 ppb, respectively. The concentration for As, Pb, Cd, and Hg with ginseng on Sangju were 3.22 ppb, 24.43 ppb, 1.44 ppb and 4.74 ppb, respectively. Also the detection concentration for As, Pb, Cd, and Hg in ginseng were also lower than the Korea Food & Drug Administration advisory level for heavy metal in herbal medicines. Residual heavy metals are not polluted in the ginseng on Punggi and Sangju at Kyeongbuk, Korea.