• 한국환경농학회지
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• 제15권3호
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• pp.275-281
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• 1996

중금속으로 오염된 토양에 콩을 재배하였을 때 토양 중 중금속함량이 콩의 생육 및 중금속흡수에 미치는 영향을 요약하면 다음과 같다. 1. 중금속 오염지역의 콩 생육은 현저히 불량하였고, 토양 중 중금속함량도 월등히 많았다. 2. 중금속 오염지역내에 재배되고 있는 작물별 잎중의 Zn, Cu, Pb, Cd, As 등 중금속함량은 콩에서 가장 많았고 다음은 옥수수, 벼 순이었다. 3. 콩의 부위별 중금속함량은 Pb외에 줄기보다 잎에서 많았으며, 원소별로는 Zn > As > Cd > Cu > Pb순이었다. 4. 콩 생육과 토양 중 Zn, Cu, Pb, Cd, As함량과는 유의한 부의 상관이 인정되었다. 5. 토양 중 Zn, Cu, Pb, Cd, As함량과 콩잎의 Zn, Cd, As함량과 콩줄기의 Pb, Cd, As함량과는 고도의 유의성이 있는것으로 보아 중금속 오염지에서는 식물체에 흡수 축적되는 것으로 생각되었다.

• Journal of Nutrition and Health
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• 제41권3호
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• pp.242-253
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• 2008

It is a common clinical practice to recommend taking iron supplements for pregnant women during gestation. Although it is required to ensure adequate iron stores during pregnancy, there has been some debate over the interference effects of excessive iron load, because it is possible to compete in the transport in the intestine and placenta and in binding to serum proteins of other trace minerals. In this study, maternal and neonatal serum concentrations of Fe, Zn, Cu, Se, Cr, Mn, and Co were assessed along with maternal Fe intakes. A total of 124 pregnant women and their term neonates participated voluntarily in this research. The women were divided into one of the three groups {high Fe intake (HFI), median Fe intake (MFI), and low Fe intake (LFI)} by their total Fe intakes and one of the two groups (Anemic and Normal) by their Fe nutritional status. All the data were compared among the three groups and between the two groups also. Total Fe intakes of HFI, MFI, and LFI groups were 140.8 ${\pm}$ 76.1, 68.0 ${\pm}$ 11.2, and 30.2 ${\pm}$ 8.6 mg/day, respectively. Those of Anemic and Normal groups were 90.1 ${\pm}$ 74.8 and 86.6 ${\pm}$ 46.8 mg/day, respectively. Maternal Hb concentration and Hct were not significantly different among HFI, MFI, and LFI groups but those were significantly different between Anemic and Normal groups. However, neonatal Hb concentration was not significantly different among HFI, MFI, and LFI groups and between Anemic and Normal groups either. Maternal serum Fe concentrations of the three groups, HFI, MFI, and LFI, were similar but that of Anemic group was significantly lower compared to Normal group. However, there was no significant difference in neonatal serum Fe concentrations among the three groups and between the two groups either. Serum concentrations of the other trace minerals in both mothers and neonates were not significantly different among HFI, MFI, and LFI groups and between Anemic and Normal groups. In addition, in the maternal serum, Fe concentration was positively correlated to Zn and Se concentration, respectively. As for the neonatal serum, Fe concentration showed a positive correlation to Zn, Cu, Mn, Se, and Co concentration, respectively. No trace mineral concentration was found to correlate negatively to Fe concentration in both maternal and neonatal serum, The results in this study indicate that Fe intakes of pregnant women, even if it is considerably above the level of estimated average requirement (EAR), may not affect serum Fe concentration in both mothers and neonates. In addition it might not influence adversely on the availability of other trace minerals including Zn and Cu in both mothers and neonates.

• Journal of Nutrition and Health
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• 제50권4호
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• pp.376-382
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• 2017

Purpose: The consistent rise in the number of foreign students in Korea demands an accurate and detailed investigation into their dietary practices and nutritional status. For these international students, assimilation into new cultures can be stressful. The influence this process may have on dietary behaviors as well as overall health cannot be overlooked. Methods: The researchers in this study sought to investigate the nutritional status and dietary practices of Ghanaian students studying in Korea. A total of 81 Ghanaian male students with an average age of $29.4{\pm}4.0years$ were sampled between May and June 2016. Investigations were carried out on the general characteristics of the participants, their daily food and nutrient intakes using a 24-h dietary recall method, meal skipping practices, and the nutritional quality of their diets based on their meal skipping habits. Results: The study revealed that the daily nutrient intake of subjects did not fully meet the daily recommended nutrient intake (RNI) established by Ghanaian Ministry of Health and the World Health Organization (WHO) and Food and Agriculture Organization (FAO), particularly for energy, calcium, iron, zinc, and vitamin B2 requirements. The Nutrient Adequacy Ratio (NAR) for calcium was very low, posing a deficiency risk to the participants. Meal skipping practices among participants changed significantly after arriving in Korea. The study also compared the diet quality indicators (Nutrient Adequacy Ratio and Mean Adequacy Ratio) of those who skipped meals ${\geq}7times/week$ with those who skipped meals < 7 times/week. Participants who skipped meals ${\geq}7times/week$ were shown to have lower dietary intakes of vitamins B1 and B2 than those who skipped meals < 7 times/week. Conclusion: Ultimately, the study found that meal skipping among Ghanaian students was common, and their daily nutrient intakes did not meet the set dietary standards. Those who skipped meals ${\geq}7times/week$ had lower dietary intakes of vitamins B1 and B2 than those who skipped meals < 7 times/week. Based on our study findings, we recommend that nutrition education should be organized for the Ghanaian student community in Korea using our results as a template to draw up a nutrition program that is culturally appropriate.

• 환경영향평가
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• 제19권5호
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• pp.475-481
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• 2010

Lots of pollutants typically originating from urban transportation are accumulating on the paved surfaces during dry periods and are washed-off directly to the river during a storm. Also, paved surfaces are contributing to increase in peak flows and volume of stormwater flows. These are the main reasons why the water quality of rivers and lakes remain polluted and still below standards. Currently, several management practices are being applied in developed countries but the design standards are still lacking. This research was conducted to develop a treatment technology that can be useful to address the problems concerning runoff quality and quantity. A lab scale infiltration device consisting of a pretreatment tank and media zone was designed and tested for various flow regimes characterizing the low, average and high intensity rainfall. Based on the experiments, the high intensity flow resulted to increase in outflow event mean concentration (EMC) of pollutants, about twice as much as the average outflow EMC. However, 78 to 88% of the total suspended solids were captured and retained in the pretreatment tank because of sedimentation. The removal of heavy metals such as zinc and lead was greatly affected by the vertical placement of woodchip layer prior to the media zone. It was observed that the high carbon content (almost 50%) in the woodchip provided opportunity for enhancing its uptake of metal by adsorption. The findings implied that the reduction of pollutants can be greatly achieved by means of proper pretreatment to allow for settling of particles with a combination of using high carbon source media like woodchip and a geotextile mat to reduce the flow before filtering into the media zone and finally discharging to the drainage system.

• 센서학회지
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• 제9권6호
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• pp.404-415
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• 2000

본 논문에서는 산불에 의한 가공송전선의 열화에 대한 몇 가지 특성들과 비파괴 검사를 다룬다. 노화된 ACSR 도체에 대한 대기부식과 전해부식과 같은 부식기구를 설명한 후에 부식검출에 대해서 기술한다. 솔레노이드 코일의 임피던스 해석을 통하여 와류센서가 도체의 싱한 결함과 국부부식을 검사하는데 유용하게 사용될 수 있음을 확인하였다. 시험 도체를 코일 내부에 삽입한 경우에 센서코일의 임피던스가 변하므로, 산불에 의해 초래된 열화 정도를 측정하는 것이 가능하였다. 인공화염에 의해 열화 된 몇 개의 시료들을 사용하여 인장강도, 신장율과 센서 임피던스가 측정되었다. 화염 기간을 어느 정도 증가시키면, 알루미늄 소선의 인장은 현저하게 감소하기 시작하나 아연도금 강소선은 약간의 아연층이 부식되지만 인장은 초기와 유사하게 유지하였다. 일반적으로 도체의 인장하중이 감소하고 반대로 신장율이 증가하면 센서 임피던스는 감소하는 것을 알 수 있었다. 따라서, 센서의 출력은 도체의 기계적 특성 변화를 나타내므로 이 센서는 산등성이에 가설된 ACSR 도체에 대해 산불로 인한 열화상태를 검출하는데 이용할 수 있다. 결국, 산불에 의한 심한 열화상태에 대한 중요한 정보를 얻는데 솔레노이드 코일을 응용할 수 있다는 것을 확인하였다.

• Journal of Preventive Medicine and Public Health
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• 제26권1호
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• pp.65-73
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• 1993

This study was carried out to evaluate the relationship between the biological lead exposure indices and air lead concentrations measured by personal air samplers. The 72 occupationally lead exposed workers were observed and the bioiogical lead Exposure indices chosen for this study were blood lead(PbB), urine lead(PbU), zinc protoporphyrin in whole blood(ZPP), $\delta$-aminolevulinic acid in urine(ALAU), $\delta$-aminolevulinic acid dehydratase activity (ALAD), coproporphyrin in urine(CPU) and hemoglobin(Hb). The workers were divided into four groups by air lead concentrations: Group I; under $0.05mg/m^3$, Group II; $0.05-0.10mg/m^3$, Group III; $0.10-0.15mg/m^3$ and Group IV; and over $0.15mg/m^3$. For evaluation the relationship between the biological lead exposure indices and air lead concentrations was used as correlation coefficients. The results obtained were as follows: 1. In Group I, II, III and IV, the mean value of PbB were $25.45{\pm}1.84{\mu}g/dl,\;27.87{\pm}3.53{\mu}g/dl,\;31.21{\pm}1.76{\mu}g/dl\;and\;47.02{\pm}13.96{\mu}g/dl$. Between Group IV and other groups showed statistically significant difference(p<0.05). 2. There was an increasing tendency of PbB, PbU, ALAU and ZPP according to the increase the mean air lead concentration, while ALAD has decreasing tendency. CPU and Hb did not show any constant tendency. 3. Correlation coefficients between PbB, PbU, ZPP, ALAU, ALAD, CPU, Hb and air lead concentration were 0.95, 0.83, 0.89, 0.72, -0.83, 0.51 and -0.45 respectively, and regression coefficient between PbB(Y) and PbA(X) was Y=126.8746X+16.9996(p<0.01).

• 한국진공학회:학술대회논문집
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• 한국진공학회 1998년도 제14회 학술발표회 논문개요집
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• pp.120-120
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• 1998

Boron nitride (BN) films have attracted a growing interest for a variety of t technological applications due to their excellent characteristics, namely hardness, c chemical inertness, and dielectrical behavior, etc. There are two crystalline phases 1551; of BN that are analogous to phases of carbon. Hexagonal boron nitride (h-BN) has a a layered s$\sigma$ucture which is spz-bonded structure similar to that of graphite, and is t the stable ordered phase at ambient conditions. Cubic boron nitride (c-BN) has a z zinc blende structure with sp3-bonding like as diamond, 따ld is the metastable phase a at ambient conditions. Among of their prototypes, especially 삼Ie c-BN is an i interesting material because it has almost the same hardness and thermal c conductivity as di없nond. C Conventionally, significant progress has been made in the experimental t techniques for synthesizing BN films using various of the physical vapor deposition 밍ld chemical vapor deposition. But, the major disadvantage of c-BN films is that t they are much more difficult to synthesize than h-BN films due to its narrow s stability phase region, high compression stress, and problem of nitrogen source c control. Recent studies of the metalorganic chemical vapor deposition (MOCVD) of I III - V compound have established that a molecular level understanding of the d deposition process is mandatory in controlling the selectivity parameters. This led t to the concept of using a single source organometallic precursor, having the c constituent elements in stoichiometric ratio, for MOCVD growth of 삼Ie required b binary compound. I In this study, therefore, we have been carried out the growth of h-BN thin f films on silicon substrates using a single source precursors. Polycrystalline h-BN t thin films were deposited on silicon in the temperature range of $\alpha$)() - 900 $^{\circ}$C from t the organometallic precursors of Boron-Triethylamine complex, (CZHs)3N:BRJ, and T Tris(dimethylamino)Borane, [CH3}zNhB, by supersonic molecular jet and remote p plasma assisted MOCVD. Hydrogen was used as carrier gas, and additional nitrogen w was supplied by either aDlIDonia through a nozzle, or nitrogen via a remote plasma. T The as-grown films were characterized by Fourier transform infrared spectroscopy, x x-ray pthotoelectron spectroscopy, Auger electron spectroscopy, x-ray diffraction, t transmission electron diffraction, optical transmission, and atomic force microscopy.roscopy.

• 한국진공학회지
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• 제6권1호
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• pp.9-19
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• 1997

본 연구에서는 실리콘 웨이퍼 표면에 존재하는 미량의 Zn, Fe, Ti 금속 오염물들이 UV-excited chlorine radical을 이용한 건식세정 방법으로 제거되는 반응과정을 찾아내고자 하였다. 실리콘 웨이퍼 상에 진공증착법으로 원형패턴이 있는 Zn, Fe, Ti 박막을 증착시켜 상온 및 $200^{\circ}C$에서 UV/$Cl_2$세정하였을 때, 염소 래디컬($Cl^*$)이 Fe, Zn, Ti와 반응하여 제거되 는 것을 반응 전후 광학현미경과 SEM을 통해 표면 형상 변화를 관찰하였고, in-line으로 연결된 XPS를 통해서 반응 후 웨이퍼 표면에 남아있는 화합물의 화학적 결합상태를 관찰 하였으며, UV/$Cl_2$ 세정 후 실리콘 기판이 손상받는 정도를 알기 위해 AFM으로 표면 거칠 기를 측정하였다. 광학현미경과 SEM의 분석 결과에 의하면 Zn와 Fe는 쉽게 제거되는 반면 염화물을 형성하기 보다는 휘발성이 적은 산화물을 형성하는 경향이 강한 Ti은 약간만 제 거되는 것을 확인하였다. XPS분석을을 통해서 이들 금속 오염물들이 chlorine radical과 반 응하여 웨이퍼 표면에 금속 염화물을 형성하고 있는 것을 확인하였고, UV/$Cl_2$세정처리를 하였을 때 실리콘 웨이퍼의 표면 거칠기가 약간 증가하는 것을 알 수 있었다. 지금까지의 결 과를 볼 때, 습식세정과 UV/$Cl_2$건식세정을 병행하면 플라즈마 및 레이저를 사용하는 다른 건식세정 방법에 비하여 보다 저온에서 실리콘 기판의 큰 손상 없이 비교적 용이하게 금속 오염물을 제거할 수 있음을 제안 하였다.

• 한국진공학회지
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• 제13권3호
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• pp.103-108
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• 2004

Atomic Layer Epitaxy (ALE)법으로 Zn 소스인 DEZn와 oxygen 소스인 $H_2O$를 사용하여 (001) sapphire 기판 위에 기판온도를 ALE 공정온도 범위 인 $170^{\circ}C$와 CVD 공정온도범위 인 $400^{\circ}C$에서 ZnO 박막을 증착하였다. 후열처리에 따른 발광 특성을 조사하기 위해서 산소분위기에서 600∼$1000^{\circ}C$의 온도로 1 시간 동안 후열처리한 후에 He-Cd laser를 사용하여 Photoluminescence (PL) 특성을 측정하였다. $170^{\circ}C$와 $400^{\circ}C$에서 증착된 시편의 경우 모두 as-grown 상태에서는 거의 발광이 일어나지 않았으나 후열처리를 거치면서 발광이 일어났으며 열처리온도가 높을수록 발광강도는 증가하였다. $400^{\circ}C$에서의 증착된 시편의 경우는 CVD 반응이 일어나 Zn-Zn 결합이 많이 생성되어 열처리 온도가 증가하여도 발광강도가 약하였고 가시광 영역의 발광이 크게 증가한 반면 $170^{\circ}C$에서 증착된 시편의 경우는 열처리 온도가 증가할수록 UV영역의 발광강도만이 크게 증가하였으며 가시광 영역에서의 발광은 거의 증가하지 않았다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2009년 추계학술발표대회
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• pp.29-29
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• 2009

On this research, laser welding technology for manufacturing automobile body is studied. Laser welding technology is one of the important technologies used in the manufacturing of lighter, safer automotive bodies at a high level of productivity; the leading automotive manufacturers have replaced spot welding with laser welding in the process of car body assembly. Korean auto manufacturers are developing and applying the laser welding technology using a high output power Nd:YAG laser and a 6-axes industrial robot. On the other hand, the robot-based remote laser welding system was equipped with a long focal laser scanner system in robotic end effect. Laser system, robot system, and scanner system are used for realizing the high speed laser welding system. The remote laser welding system and industrial robotic system are used to consist of robot-based remote laser welding system. The robot-based remote laser welding system is flexible and able to improve laser welding speed compared with traditional welding as spot welding and laser welding. The robot-based remote laser systems used in this study were Trumpf's 4kW Nd:YAG laser (HL4006D) and IPG's 1.6kW Fiber laser (YLR-1600), while the robot systems were of ABB's IRB6400R (payload:120kg) and Hyundai Heavy Industry's HX130-02 (payload:130kg). In addition, a study of quality evaluation and monitoring technology for the remote laser welding was conducted. The welding joints of steel plate and steel plate coated with zinc were butt and lapped joints. The quality testing of the laser welding was conducted by observing the shape of the beads on the plate and the cross-section of the welded parts, analyzing the results of mechanical tension test, and monitoring the plasma intensity and temperature by using UV and IR detectors. Over the past years, Trumf's 4kW Nd:YAG laser and ABB's IRB6400R robot system was used. Nowadays, the new laser source, robot and laser scanner system are used to increase the processing speed and to improve the efficiency of processes. This paper proposes the robot-based remote laser welding system as a means of resolving the limited welding speed and accuracy of conventional laser welding systems.