• 대한화장품학회지
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• 제50권1호
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• pp.77-84
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• 2024

사용 연령이 만 4 세 이상부터 표시된 어린이 화장품세트 4 건을 온라인으로 구매하였으며 각 구성품 81 건을 대상으로 납, 카드뮴, 비소, 안티몬, 니켈, 코발트, 구리, 크롬 및 수은의 함량을 inductive coupled plasma-mass spectrometry (ICP - MS)로 분석하였다. 어린이 화장품의 중금속 평균값은 납 0.82 ㎍/g, 카드뮴 0.03 ㎍/g, 비소 0.97 ㎍/g, 안티몬 0.52 ㎍/g, 니켈 2.32 ㎍/g, 수은 0.01 ㎍/g으로 모든 제품에서 허용 기준보다 낮았다. 국산과 수입산의 비교 결과, 국산보다는 수입산에서 납, 안티몬, 코발트, 구리의 평균값이 높게 검출되었다(p < 0.05). 화장품 유형에 따른 중금속 평균값은 통계적으로 유의한 차이를 보였는데(p < 0.05) 아이새도에서 비소 2.47 ㎍/g, 니켈 6.36 ㎍/g, 크롬 11.06 ㎍/g으로 평균값이 가장 높게 나왔으며, 볼연지에서 납 1.20 ㎍/g, 안티몬 1.17 ㎍/g, 구리 23.60 ㎍/g으로 가장 높게 나왔다. 분석된 81 건의 어린이 화장품에 대한 코발트의 검출 수준은 불검출 ~ 5.23 ㎍/g, 구리는 불검출 ~ 379.61 ㎍/g, 크롬은 불검출 ~ 36.95 ㎍/g이었다. 브라운 색상의 화장품은 니켈과 코발트에서 평균값이 높게 검출되었으며, 퍼플 색상은 납과 크롬에서 높게 검출되었다.

• 농업생명과학연구
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• 제53권1호
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• pp.117-126
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• 2019

본 연구는 수평 원통형 퇴비화 장치를 이용하여 퇴비를 생산할 때, 폐사축을 동시에 처리할 수 있는 가능성 여부를 판단하기 위하여 실험을 진행하였다. 그 결과 중금속의 경우, 아연의 함유량이 일반 운전의 일부 측정구와 폐사축 운전의 전체 측정구에서 허용함유량 보다 초과하는 것으로 나타났다. 특히 폐사축 운전의 경우, 구리 함량도 일반 운전에 비해 높게 나타났다. 우드칩 운전의 경우, 모든 중금속이 허용치보다 낮게 나타났으며, 구리, 카드뮴 및 비소의 경우는 폐사축 운전과 유사하거나 동일 수준으로 나타났다. 단지 니켈의 함유량이 29.5~63.8% 정도로써 일반 및 폐사축 운전에서 각각 9.3~18.0% 및 15.8~18.0% 정도 함유한 것에 비해 상대적으로 높게 나타났다. 그리고 크롬의 경우도 14.2~31.9% 정도로서 일반 및 폐사축 운전에 비해 상대적으로 높게 나타났다. 통합 운전의 경우도 모든 중금속이 허용치보다 낮게 나타났으며, 구리와 아연의 함유량은 각각 34.9~54.5% 및 53.1~75.9% 정도로서 우드침 운전의 경우인 48.9~52.6% 및 64.6~85.9% 정도와 유사하였다. 그리고 우드칩 운전에서 다소 높게 나타났던 크롬과 니켈의 함량도 안정화 된 것으로 나타났다. 함수율은 폐사축 운전의 경우, 평균 및 최종치가 60.7% 및 49.6% 정도로서 평균치가 권장치인 55.0% 보다 다소 높게 나타났지만, 최종 함수율은 권장치인 55.0% 보다 낮게 나타났다. 통합 운전의 경우, 평균 및 최종 함수율이 각각 29.2% 및 18.6% 정도로서 4개의 운전 중에 상대적으로 가장 낮게 나타났다. 그리고 운전별로 다소차이는 있지만, 전체적으로 권장치인 55.0% 보다 낮게 나타났다. C/N비의 경우, 폐사축 운전에서 상대적으로 가장 낮게 나타났고, 일반 운전에서 가장 높게 나타났다. 운전별로 보면, C/N비의 평균치가 13.7~20.3 정도의 범위이고, 전체평균이 18.3 정도로서 전체적으로 적정치인 30.0 이하를 유지하였다.

• 광물과 암석
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• 제36권4호
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• pp.323-336
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• 2023

핵심 광물인 니켈의 국내 확보를 위해 충남 유구지역 초염기성암에 대한 니켈 잠재성 및 성인 연구를 수행하였다. 경기육괴의 남서쪽에 위치한 유구 초염기성암은 첨정석 감람암으로, 경계부를 따라 사문석화가 강하게 진행되어 있다. 사문석화작용으로 감람석은 안티고라이트 및 크리소타일로, 니켈 황화광물인 펜틀란다이트는 밀러라이트 및 어웨루이트로 변질되었다. 사문석은 일부 강한 엽리를보이며, 초염기성암 경계 및 유구편마암 면구조와 주로 평행하게 발달한다. 이는 초염기성암의 융기 과정 동안 편마암의 변성작용으로부터 공급받은 열수가 단층 경계를 따라 침투하여 사문석화된 것으로 해석된다. 유구 초염기성암의 기원은 심해저 페리도타이트이며 약 5~18% 정도의 부분 용융을 겪은 잔여물로 해석된다. 부화된 경희토류원소 및 Eu는 맨틀이 2차적인 교대변성작용을 겪었음을 암시한다. 이러한 지화학 결과는유구 감람암의 형성이 중생대 초기 북중국판과 남중국판의 대륙 충돌과 관련 있음을 시사한다. 유구 초염기성암 내 니켈은 0.17~0.21%로, 상당량이 감람석 및 사문석에 포함된다. 따라서 마그마 기원인 유구 초염기성암의 니켈 회수율을 높이기 위해 황화광물의 선광연구와 더불어 산화광물을 대상으로 하는 침출 연구가 요구된다.

• 한국산업보건학회지
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• 제16권3호
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• pp.254-263
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• 2006

Manganese has a role as both toxic and essential in humans. Manganese is also an essential component in the welding because it increases the hardness and strength, prevents steel from cracking of welding part and acts as a deoxidizing agent to form a stable weld. In this study, manganese generation rate and its content was determined in flux cored arc welding on stainless steel. Domestic two products and foreign four products of flux cored wires were tested in the well designed fume generation chamber as a function of input power. Welding fume was measured by gravimetric method and metal manganese was determined by inductively coupled plasma-atomic emission spectrophotometer. The outer shell of the flux cored wire tube and inner flux were analyzed by scanning electron microscopy to determine their metal compositions. Manganese generation rate($FGR_{mn}$) was increased as the input power increased. It was 16.3 mg/min at the low input power, 38.1 mg/min at the optimal input power, and up to 55.4 mg/min at the high input power. This means that $FGR_{mn}$ is increased at the work place if welder raise the current and/or voltage for the high productivity. The slope coefficient of $FGR_{mn}$ was smaller than that of the generation rate of total fume(FGR). Also, the correlation coefficient of $FGR_{mn}$ was 0.65 whereas that of FGR is 0.91. $FGR_{mn}$ was equal or higher in the domestic products than that of the foreign products although FGR was similar. From the electron microscopic analytical data, we concluded that outer shell of the wire was composed mainly of iron, chromium, nickel and less than 1.2 % of manganese. There are many metal ingredients such as iron, silica, manganese, zirconium, titanium, nickel, potassium, and aluminum in the inner flux but they were not homogeneous. It was found that both $FGR_{mn}$ and content of manganese was higher and more varied in domestic flux cored wires than those of foreign products. To reduce worker exposure to fumes and hazardous component at the source, further research is needed to develop new welding filler materials that improve the quality of flux cored wire in respect to these points. Welder should keep in mind that the FGR, $FGR_{mn}$ and probably the generation rate of other hazardous metals were increased as the input power increase for the high productivity.

• 한국재료학회지
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• 제24권11호
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• pp.632-638
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• 2014

We investigated the effects of DMAB (Borane dimethylamine complex, C2H10BN) in electroless Ni-B film with addition of DMAB as reducing agent for electroless Ni plating. The electroless Ni-B films were formed by electroless plating of near neutral pH (pH 6.5 and pH 7) at $50^{\circ}C$. The electroless plated Ni-B films were coated on screen printed Ag pattern/PET (polyethylene terephthalate). According to the increase of DMAB (from 0 to 1 mole), the deposition rate and the grain size of electroless Ni-B film increased and the boron (B) content also increased. In crystallinity of electroless Ni-B films, an amorphization reaction was enhanced in the formation of Ni-B film with an increasing content of DMAB; the Ni-B film with < 1 B at.% had a weak fcc structure with a nano crystalline size, and the Ni-B films with > 5 B at.% had an amorphous structure. In addition, the Ni-B film was selectively grown on the printed Ag paste layer without damage to the PET surface. From this result, we concluded that formation of electroless Ni-B film is possible by a neutral process (~green process) at a low temperature of $50^{\circ}C$.

• 환경위생공학
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• 제24권3호
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• pp.28-36
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• 2009

We have closely examined the concentration change characteristics, emission amounts, and the material balance of hazardous air pollutants at both early and later stages of the prevention facilities. These results will be uses as the basic data when preparing for the regulatory and management plans for hazardous air pollutants. The results of the study on heavy metals illustrated that the content of heavy metals in sludge across five facilities were as follows: copper> zinc> chrome> nickel> cadmium> mercury. In terms of heavy metal content in swage sludge, the sludge in incinerating facilities other than the sludge in the D incinerating facility containing industrial water waste, was examined in order to satisfy the ocean contamination standard and fertilizer specifications. Most of the items were shown to have satisfied the emission tolerance standards in the latter part of the prevention facilities(The average elimination rate was over 90%). Therefore, it is concluded that swage sludge containing high-concentrate heavy metals needs to be incinerated rather than recycled as fertilizer.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.172-181
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• 2001

Upflow anaerobic sludge blanket (UASB) system employs granular sludge to treat various wastewaters including landfill leachate. CH$_4$ production of the granules determines overall performance of a UASB reactor. Sludge granules are developed by self-granulation of microorganisms and dynamic balance between granule growth and decay results in coexistence of granules with different sizes in the reactor. In this study, granules taken from a laboratory-scale UASB reactor were classified into 4 groups based on their diameters and their Physicochemical characteristics we were investigated. Each group was analyzed for settling ability, specific methanogenic activity (SMA), and elemental content. Settling ability was proportional to granule diameter. suggesting effective detainment of larger granules in the reactor. When acetate or glucose was used as a substrate, all groups showed relatively slight difference in SMA. However SMA with a volatile fatty acid mixture showed significant increase with granule diameter, suggesting better establishment of syntrophic relationship in larger granules. Larger granules showed higher value of SMA upon environmental changes (i.e., PH, temperature, or toxicant concentration). Comparative analysis of elemental contents showed that content (dry weight %) of most tested elements (iron, calcium, phosphorus, zinc, nickel. and manganese) deceased with granule diameter, suggesting importance of these elements for initial granulation. Taken together, this study verified experimentally that Physicochemical Properties of granules are related to granule size distributions. Overall results of physicochemical characterization supports that larger.

• 한국표면공학회지
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• 제40권1호
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• pp.32-38
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• 2007

Ni coating layers were formed using a newly developed electroless Ni plating solution. The properties of Ni coating layer such as internal stress, hardness, surface roughness, crystallinity, solderability and surface morphology were investigated using various tools. Results revealed that internal stress decreased with plating time and reached $40N/mm^2$ at 20 minutes of the plating time. Hardness increased with increasing P content and thickness. Surface roughness of the pad decreased with Ni and Ni/Au plating. Crystallinity decreased with increasing P content. Solderability based on wettability decreased with Ni and Ni/Au plating. Based on surface morphology, it is expected that Ni coating layer formed using a newly developed electroless Ni plating solution is lower than that formed using a commercial electroless Ni plating solution in possibility of black pad occurrence.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.178-179
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• 2014

In this study, $Ni-W-Si_3N_4$ alloy composite coatings were prepared by pulse electrodeposition method using nickel sulfate bath with different contents of tungsten source, $Na_2WO_4.2H_2O$, and dispersed $Si_3N_4$ nano particles. The structure and microstructure ofcoatings was separately analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Results indicated that nano $Si_3N_4$ and W content in alloy had remarkable effect on microstructure, microhardness and scratch resistant properties. Tungsten content in Ni-W and $Ni-W-Si_3N_4$ alloy ranged from 7 to 14 at.%. Scratch test results suggest that as compared to Ni-W only, $Ni-W-Si_3N_4$ prepared from Ni/W molar ratio of 1:1.5 dispersed with 20 g/L $Si_3N_4$ has shown the best result among different samples.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.171-172
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• 2015

$Ni-W-Si_3N_4$ alloy composite coatings were prepared by pulse electro-deposition method using nickel sulfate bath with different contents of tungsten source, $Na_2WO_4.2H_2O$, and dispersed $Si_3N_4$ nano-particles. The structure and micro-structure of coatings was separately analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Results indicated that nano $Si_3N_4$ and W content in alloy had remarkable effect on micro-structure, micro-hardness and scratch resistant properties. Tungsten content in Ni-W and $Ni-W-Si_3N_4$ alloy ranged from 7 to 14 at.%. Scratch test results suggest that as compared to Ni-W only, $Ni-W-Si_3N_4$ prepared from Ni/W molar ratio of 1:1.5 dispersed with 20 g/L $Si_3N_4$ has shown the best result among different samples.