• 한국산업보건학회지
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• 제9권1호
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• pp.56-72
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• 1999

Airborne concentrations of welding fumes in which 13 different metals such as Al, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Si, Sn, Ti, and Zn were analyzed were measured at 18 factories including automobile assembly and manufactures, steel heavy industries and shipyards. Air samples were collected by personal sampler at each worker's worksite(n=339). Blood levels of Cd, Cu, Fe, Mn, Pb and Zn were also measured from samples taken from 447 welders by atomic absorption spectrometry and compared with control values obtained from 127 non-exposed workers. The results were as follows ; 1. Among various welding types, $CO_2$ welding 70.2 % were widely used, shielded metal arc welding(SMAW) 22.1 % came next, and rest of them were metal inert gas(MIG) welding, submerged arc welding(SAW), spot welding(SPOT) and tungsten inert gas(TIG) welding. 2. Welding fume concentration was $0.92mg/m^3$($0.02{\sim}15.33mg/m^3$) at automobile assembly and manufactures, $4.10mg/m^3$($0.02{\sim}70.75mg/m^3$) at steel heavy industries and $5.59mg/m^3$($0.30{\sim}91.16mg/m^3$) at shipyards, respectively, showing significant difference among industry types. Workers exposed to high concentration of welding fumes above Korean Permissible Exposure Limit(KPEL) amounted to 7.9 % and 12.5 %, in $CO_2$ welding and in SMAW at automobile assembly and manufactures and 62.7 % in $CO_2$ welding, and 12.5 % in SMAW at shipyards, and 66.2 % in $CO_2$ welding and 70.6 % in SMAW at steel heavy industries. 3. Geometric mean of airborne concentration of each metal released from welding fumes was below one 10th of KPEL in all welding types. Percentage of workers, however, exposed to airborne concentration of metals above KPEL amounted to 16.8 % in Mn and 7.6 % in Fe in $CO_2$ welding; 37.5 % in Cu in SAW, 30 % in Cu in TIG; and 25 % in Pb in SPOT welding. As a whole, 76 Workers(22.4%) were exposed to high concentration of any of the metals above KPEL. 4. There were differences in airborne concentration of metals such as Al, Cd, Cr, Cu. Fe. Mn, Mo, Ni, Pb, Si, Sn, Ti and Zn by industry types. These concentrations were higher in shipyards and steel heavy industries than in automobile assembly and manufactures. Workers exposed to higher concentration of Pb above KPEI amounted to 7.4 % of workers(7/94) in automobile assembly and manufactures. In shipyards, 19.2 % of workers(19/99) were over-exposed to Mn and 7.1 % (7/99) to Fe above KPEL. In steel heavy industries, 14.4 %(21/146), 7.5 %(11/146) and 13 %(19/146) were over-exposed to Mn, Fe and Cu, respectively. As a whole, 76 out of 339 workers(22.4%) were exposed to any of the metals above KPEL. 5. Blood levels of Cd, Cu, Fe, Mn, Pb, and Zn in welders were $0.11{\mu}g/100m{\ell}$, $0.84{\mu}g/m{\ell}$, $424.4{\mu}g/m{\ell}$, $1.26{\mu}g/100m{\ell}$, $5.01{\mu}g/100m{\ell}$ and $5.68{\mu}g/m{\ell}$, respectively, in contrast to $0.09{\mu}g/100m{\ell}$, $0.70{\mu}g/m{\ell}$, $477.2{\mu}g/m{\ell}$, $0.73{\mu}g/100m{\ell}$, $3.14{\mu}g/100m{\ell}$ and $6.15{\mu}g/m{\ell}$ in non-exposed control groups, showing significantly higher values in welders but Fe and Zn.

• Asian Pacific Journal of Cancer Prevention
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• 제17권10호
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• pp.4761-4767
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• 2016

Objective: The use of Shamma (smokeless tobacco) by certain groups is giving rise to health problems, including cancer, in parts of Saudi Arabia. Our objective was to determine metals levels in Shamma using inductively coupled plasma mass spectrometry (ICP-MS). Methods: Thirty-three samples of Shamma (smokeless tobacco) were collected, comprising four types: brown Shamma (n = 14.0), red Shamma (n = 9.0), white Shamma (n = 4.0), and yellow Shamma (n = 6.0). All samples were collected randomly from Shamma users in the city of Najran. Levels of 11 elements (Al, As, Cd, Co, Cr, Cu, Li, Mn, Ni, Pb, and Zn) were determined by ICP-MS. Results: A mixed standard (20 ppb) of all elements was used for quality control, and average recoveries ranged from 74.7% to 112.2%. The highest average concentrations were found in the following order: Al ($598.8-812.2{\mu}g/g$), Mn ($51.0-80.6{\mu}g/g$), and Ni ($23.2-53.3{\mu}g/g$) in all four Shamma types. The lowest concentrations were for As ($0.7-1.0{\mu}g/g$) and Cd ($0.0-0.06{\mu}g/g$). Conclusions: The colour of each Shamma type reflects additives mixed into the tobacco. Cr and Cu were showed significant differences (P < 0.05) among Shamma types. Moreover, Pb levels are higher in red and yellow Shamma, which could be due to use (PbCrO4) as yellow colouring agent and lead tetroxide, Pb3O4 as a red colouring agent. The findings from this study can be used to raise public awareness about the safety and health effects of Shamma, which is clearly a source of oral exposure to metals.

• 한국세라믹학회지
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• 제26권2호
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• pp.201-209
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• 1989

Fine Si-Al-OH coprecipitate powders were prepared from Si- and Al-alkoxides by the hydrolysis method. $\beta$-Sialon powder was obtained from prepared Si-Al-OH coprecipitate by the simultaneous reduction and nitridation method. The syntehsized Sialon powder was pressureless sintered at 175$0^{\circ}C$ for 90 min in N2 atmosphere. The characterization of the Sialon powder was performed with XRD, BET, SEM, TEM and particle size analysis. The sinterability and mechanical properties of sintered bodies were investigated in terms of relative density, M.O.R., fracture toughness, hardness and the morphology of microstructure. The highest values of their mechanical properties were obtained for the $\beta$-Sialon ceramics at Z=1 and those values are as follows : M.O.R., KIC and HV of $\beta$-Sialon ceramics(Z=1) are 499.1 MPa, 5.9MN/m3/2 and 18.7GPa, respectively.

• KSBB Journal
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• 제10권4호
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• pp.441-448
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• 1995

토양으로부터 분리 동정된 균주인 Bacillus polymyxa KS-1을 이용하여 이들이 생산하는 미생물 생 다당듀 KS-1의 생산을 위한 배지 및 배양조건을 조사하였다. 다당류 KS-1의 생산을 위한 애지의 조성은 증류수 1 liter당 glucose 30g, yeast extract $2.5g, KH_2PO_4 2.5g, NaCl 0.5g, MgSO_4.7H_20 0.3g, CaC0_3 0.05g, FeSO_4.7H_2O 0.05g, 그리고 MnS0_4 . 4H_20 0.05g$ 이 첨가된 배지에서 높은 정성 벚 다탕류 생산 을 얻을 수 있었으며, 이때 배양조건은 초기 pH와 배양온도는 각각 7.0과 $30^{\circ}C$, C에서 다당류 생산이 가 장 좋은 갯으로 조사되였다. 또한 이상의 최적조건 에서 발효조를 이용한 경우 통기량 빛 교반속도를 각각 2vvm과 400rpm으로 조절하여 배양한 경우 생산량은 liter당 약 10.3g의 다당류 KS-1이 얻어졌다.

• 대한환경공학회지
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• 제28권7호
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• pp.704-712
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• 2006

본 연구에서는 여러 가지 점토광물의 흡착에 의한 $Al^{3+}$, $Cu^{2+}$, $Mn^{2+}$, $Pb^{2+}$ 및 $Zn^{2+}$와 같은 중금속 제거특성을 고찰하였다. 흡착제로는 원료 벤토나이트와 본 연구과정에서 제조한 칼슘 및 나트륨형 벤토나이트, 몬모릴로나이트계 광물인 KSF와 K10을 사용하였다. 이들 다섯 가지 점토광물의 조성은 XRF를 이용하여 분석하였으며 중금속의 농도는 ICP를 이용하여 측정하였다. 또한 각 점토광물의 양이온교환능력과 전하량을 측정하여 비교하였다. 실험결과, 흡착평형은 약 $1{\sim}2$시간 후에 도달하였다. $Na^+$ 치환형 벤토나이트는 $Mn^{2+}$을 제외한 모든 중금속에 대하여 최고 98% 이상의 높은 흡착효율을 나타내었으며 $Mn^{2+}$에 대해서는 최고 66%의 흡착효율을 보였다. KSF는 pH가 증가함에 따라 $Al^{3+}$이 용출되는 것으로 나타났지만 $Pb^{2+}$과 $Zn^{2+}$은 산성을 띠고 있는 KSF에 의하여 각각 최고 88%와 59%의 흡착효율을 나타냄으로써 수소이온농도에 크게 영향을 받지 않는 것으로 나타났다. 전반적으로 중금속의 초기 농도가 증가함에 따라 흡착효율은 감소하고 흡착능(흡착용량)은 증가하는 경향을 나타내었다. $Na^+$ 치환형 벤토나이트의 중금속 흡착능은 농도에 따라 $1.3{\sim}19$ mg/g 정도의 값을 나타내었다. 흡착제 1 g당 각 중금속들의 흡착량은 $Na^+$ 치환형 벤토나이트$\gg$원료 벤토나이트$\approx$K10>$Ca^{2+}$ 치환형 벤토나이트$\gg$KSF의 순서로 나타났다. 프런들리히 흡착등온선으로부터 K와 1/n값을 계산한 결과, $Na^+$ 치환형 벤토나이트의 K값이 모든 중금속에 대하여 가장 크게 나타났으며 1/n은 $0.2{\sim}0.39$ 범위로 나타나 중금속 흡착에 가장 적합한 점토광물임을 알 수 있었다. 또한 흡착능은 Al>Cu>Pb>Zn>Mn 순으로 나타났다.

• Journal of Periodontal and Implant Science
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• 제24권1호
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• pp.39-49
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• 1994

It has been believed that antioxidant enzymes such as CuZn- and Mn-superoxide dismutase and catalase protect the tissue from damage resulting from the oxygen derived free radicals($O_2\;^-$, $H_2O_2$ and OH ). The purpose of this study was to investigate the relationship between activity of antioxidant enzymes including CuZn- and Mn- superoxide dismutase and catalase and inflammatory periodontal disease and periodontal parameters. For this study, the patients were classified into normal, gingivitis, adult periodontitis and rapidly progressive periodontitis, and then their papillary bleeding index(PBI) and probing depth were checked. Gingival tissues were surgically obtained from the patients during periodontal surgery, extraction, and clinical crown lengthening procedure. The activity of CuZn- and Mn- superoxide dismutase and catalase in the gingival tissues was measured by using UV-spectrophotometer by the same methods as Crapo et al. And Aebi did, respectively. The results were as follows : 1. CuZn- and Mn- and total-superoxide dismutase activity were significantly low in rapidly progressive periodontitis group in comparison to normal group (P<0.05). 2. In comparison of the antioxidant enzyme activity according to papillary bleeding index group(PBI), Mn-superoxide dismutase activity only was significantly lower in PBI 2, 3, and 4 groups than PBI 0 group(P<0.05). 3. Superoxide dismutase activity failed to show any significant difference according to probing depth. But significant]y high catalase activity was shown in deep pocket group (${\ge}7mm$)(P<0.05). In conclusion, these results suggest that the activity of Mn-superoxide dismutase among the antioxidant enzymes may reflect the inflammatory status of gingival tissue and that the decreased activity of superoxide dismutase may be one of responsibe factors for progression of rapidly progressive periodontitis.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1996년도 경북지부 결성 및 추계학술발표회 논문집
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• pp.140-143
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• 1996

산성강하물이 산림토양에 미치는 영향을 조사하기 위하여 오염이 우려되는 공단지역(울산, 여천)과 대도시지역(서울, 부산), 그리고 비오염지역인 대조지역(평창, 삼천포)을 대상으로 이들 지역의 산림토양의 특성을 조사하였다. 또한, 이들지역 각각을 대표할 수 있는 산림토양에 인공산성비를 유출시켜 토양의 화학적 성질의 변화를 조사한 결과는 다음과 같다. - 조사지역별 토성분포는 일정한 경향을 보이지 않았으며, 전체 조사지역 토성은 양토(29.0%), 식양토(22.9%), 사양토(18.3%) 3종류가 분포율이 높았고, 이들이 전체의 70.2%를 차지하였다. - 조사지역 전체 산림토양 표토의 pH($H_2O$)는 4.41~5.14 범위로 평균 4.49이고, 심토의 pH($H_2O$)는 4.54 ~ 5.22 범위로 평균 4.69이었다. 지역별로 보면 공단지역(4.44) < 대도시지역(4.57) < 대조지역(5.08) 순서로 토양 pH가 낮은 경향을 나타냈다. - 염기포화도는 3.07 ~ 21.83% 범위이고, 평균값은 7.71%이었다. 지역별 비교에서는 대조지역(19.14%) > 공단지역(6.54%) > 대도시지역(5.60%) 순서로 높은 경향을 보였다. - 치환성 Al 함량은 2.13 ~ 5.59cmol(+)/kg 범위이고 평균 4.62cmol(+)/kg이었다. 지역별 비교에서는 대조지역(2.34) < 대도시지역(3.23) < 공단지역(5.20) 순서로 낮은 경향을 나타냈다. - 4종의 인공산성우(pH 2.0, 3.0, 4.0 및 5.6)를 산림토양에 유출시킨 결과 인공산성우의 유출량이 증가함에 따라 토양유출액의 pH 감소, 토양염기의 유실이 지속적으로 나타났고, AL과 Mn의 용탈량이 증가하는 경향을 나타내었는데, 이러한 현상은 pH 3.0 인공산성우 유출시에 시작되어 pH 2.0에서 뚜렸하였다. - 인공산성우 토양유출 실험결과 울산, 남산 및 평창토양은 H 부하량의 증가에 따른 치환성염기 및 Al과 Mn의 용탈양상은 Sigmoid curve인 y = a/{1+exp(-c+bx)} 모델식에 따랐다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.77.1-77.1
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• 2007

• 환경영향평가
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• 제12권2호
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• pp.99-108
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• 2003

We collected and analyzed PM10 samples to account for the characteristics of heavy metallic elements for yellow sand and non-yellow sand during springtime of 2002 at Busan, The mean PM10 mass concentration for springtime of 2002 was $219.82{\mu}g/m^3$ with the maximum $787.50{\mu}g/m^3$ and the minimum $19.44{\mu}g/m^3$. The mean concentration of metallic elements contained in PM10 are shown as follows : Si>Ca>Fe>Al>Na, respectively. The ratio of mean PM10 mass concentration for yellow sand($362.7{\mu}g/m^3$) to that for non-yellow sand($48.3{\mu}g/m^3$) was 7.5, the significant positive correlation (P<0.05) was found between yellow sand and non-yellow sand. The metallic elements concentration ratios of yellow sand to the non-yellow sand were over 10 times for Al, Ca, Mg, 4~8 times for Fe, Si, Mn. But the concentration of Na, Cu, Zn for non-yellow sand was higher than those of yellow sand. The crustal enrichment factor of Cd, Cu, Pb, Zn, Cr, K, Mn, Na, Ni for yellow sand was higher that of non-yellow sand over 10 times, and concentration rate of soil particles of yellow sand was increased 2.3 times that of nonyellow sand.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1148-1151
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• 2002

Dielectric ceramics with nominal composition of $(Ba_{0.93}Sr_{0.07}O)-0.5Sm_2O_3-4.5TiO_2$ was prepared using the conventional mixed oxide process-derived powder. Effect of $SiO_2$, $MnO_2$ and $Al_2O_3$ impurity addition on the microwave properties was examined in some detail. Measured relative permittivity $(\varepsilon_r)$ values were in the range of 53 to 59 and showed little dependence on impurity addition. In contrast, quality factor $(Q{\cdot}f)$ and temperature coefficient of resonant frequency $(\tau_f)$ values were greatly influenced by the type and the amount of impurities. It was found that 0.1~0.2wt% addition of $Al_2O_3$ was most effective for improving the properties, where ${\varepsilon}_r$, $Q{\cdot}f$ and $\tau_f$ values were 57.7, 10000, and +7ppm/$^{\circ}C$, respectively.