• 한국한의학연구원논문집
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• 제6권1호
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• pp.117-122
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• 2000

The purpose of this study is to compare the contents of heavy metals of boiled ssangwhatang with those of herbal ingredients which are composed of ssangwhatang. Ssangwhatang is used for antifatigue, tonic and so on. With industrial development, our environment has been very polluted. Herbal medicines also are seriously contaminated by heavy metals and pesticides. The herbal medicines of ssangwhatang were bought at 10 defferent markets. The contents of 14 heavy metals(Ag, As, Ba, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Sn, Zn) were analysed using ICP. It was found out that 7 heavy metals(Pb, As, Ba, Cd, Hg, Sb, Sn) were not detected at all in boiled ssangwhatangs. But they were detectable in all ssangwhatangingredients before boiling. For example, the content of Pb in one pack of ssangwhatang before boiling was $0.039^{\circ}{\pm}0.005mg$ and Pb in boiled one was not detected. Herbal medicine itself is seriously contaminated by heavy metals. These results suggest that boiled ssangwhatang which we take is safe from the contamination of heavy metals.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.491-498
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• 2005

Acid Rock Drainage(ARD) is the product formed by the atmospheric(i.e. by water, oxygen and carbon dioxide) oxidation of the relatively common iron-sulphur minerals pyrite($FeS_2$). ARD causes the acidification and heavy metal contamination of water and soil and the reduction of slope stability. In this study the generation characteristics and the prediction of ARD of various road cut slopes were studied. An attempt to classify the rocks into several groups according to their acid generation potentials was made. Acid Base Accounting(ABA) tests, commonly used as a screening tool in ARD predictions, were performed. Sixteen rock samples were classified into PAF(potentially acid forming) group and four rock samples into NAF(non-acid forming) group. The chemical analysis of water samples strongly suggested that ARD with high content of heavy metals and low pH could pollute the ground water and/or stream water.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.368-371
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• 2003

Accidental release of petroleum products from underground storage tank(USTs) is one of the most common causes of groundwater contamination. BTEX is the major components of fuel oils, which are hazardous substances regulated by many nations. In addition to BTEX, other gasoline consituents such as MTBE(methyl-t-buthyl ether), anphthalene are also toxic to humans. Natual attenuation processes include physic, chemical, and biological trasformation. Aerobic and anaerobic biodegradation are believed to be the major processes that account for both containment of the petroleum-hydrocarbon plum and reduction of the contaminant concentrations. Aerobic bioremediation has been highly effective in the remediation of many fuel releases. However, Bioremediation of aromatic hydrocarbons in groundwater and sediments is ofen limited by the inability to provide sufficient oxygen to the contaminated zones due to the low water solubility of oxygen. Anaerobic processes refer to a variety of biodegradation mechanisms that use nitrate, ferric iron, sulfate, and carbon dioxide as terminal electron accepters. The objectives of this study was to conduct laboratory-scale microcosm studies in assessing enhanced bioremediation potential of BTEX and MTBE under various electron accepters(aerobic, nitrate, ferric iron, sulfate) in contaminated Soil. these results suggest that, presents evidence and a variety pattern of the biological removal of aromatic compounds under enhanced nitrate-, Fe(III)-, sulfate-reducing conditions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.802-807
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• 2002

The updating of FE model to match it with the experimental results needs the modal information. There are two cases where this methodology is ill-equip to deal with； under-determined and ill-conditioning problem. The feedback exciter that uses the summation of the white noise and the signals from the measurement sensors multiplied with feedback gains can deal with these problems as the new modal data from the closed loop system generate more constraints the updating parameters should obey. The new modal data from the closed loop system should be different to enhance the condition of the modal sensitivity matrix. In this research, a guide for the selection of the sensor locations and the decision of the corresponding output feedback gains is proposed. This method is based on the sensitivity of the modal data with respect to the feedback gains. Through the proper selection of the exciter and sensor locations and the feedback gain, the eigenvalue sensitivity of the updating parameters which cause the ill-conditioning of the modal sensitivity matrix can be modified and consequently the error contamination in updating parameters are reduced.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.225-228
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• 2003

For the purpose of finding out the distributions of groundwater uses, the effect of facilities on the parameter and the correlations among measurements, various statistical analysis were carried out with the data of groundwater quality measurements from January to December in 2002. 1. The rates of groundwater for drinking water were 10.5% in Yangcheon-Gu, 10.2% in Kangdong-Gu, and 9.9% in Eunpyung-Gu. The rates of other uses of groundwater were shown to be 58.1%(786 wells) for civil defense emergency, 22.1%(299 wells) for contamination-concerning, 9.8%(133 wells) for water quality monitoring, consisting of 90% of all groundwater. 2. The 52.6% of groundwater for drinking were demonstrated to be appropriate while 91.9% for tither uses-domestic, industrial, agricultural uses- were shown to be proper. 3. For drinking water, the average values of colar, turbidity, NH3-N, F, and Fe were 11.216 degree, 2.138 NTU, 2.458mg/l, 0.212mg/1 and 0.507mg/1 respectively. 4. In cases of drinking water wells for emergency, the results of statistical analysis showed that building year of the wells, depth and pumping rate didn't affect on whether it was proper for that use or not. It were shown that there were linear correlations between depth and NO$_3$-N(-0.171) and F￣(0.332) while the correlation coefficients were 0.381 and -0.169 between the building year of well and depth and pumping rate respectively.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권6호
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• pp.1-9
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• 2011

A bibliographical review of Gy sampling theory for particulate materials was conducted to provide readers with useful means to reduce errors in soil contamination investigation. According to the Gy theory, the errors caused by the heterogeneous nature of soil include; the fundamental error (FE) caused by physical and chemical constitutional heterogeneity, the grouping and segregation error (GE) aroused from gravitational force, long-range heterogeneous fluctuation error ($CE_2$), the periodic heterogeneity fluctuation error ($CE_3$), and the materialization error (ME) generated during physical process of sample treatment. However, the accurate estimation of $CE_2$ and $CE_3$ cannot be estimated easily and only increasing sampling locations can reduce the magnitude of the errors. In addition, incremental sampling is the only method to reduce GE while grab sampling should be avoided as it introduces uncertainty and errors to the sampling process. Correct preparation and operation of sampling tools are important factors in reducing the incremental delimitation error (DE) and extraction error (EE) which are resulted from physical processes in the sampling. Therefore, Gy sampling theory can be used efficiently in planning a strategy for soil investigations of non-volatile and non-reactive samples.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.581-581
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• 2012

나노스케일에서의 자구체(magnetic domain), 자화벽(magnetic domain wall)에 대한 연구가 활발하게 진행되고 있으며 특히 자화벽의 위치를 임의로 제어할 수 있는 기술을 응용한 메모리 소자에 대한 연구가 활발하다. 반면에 이러한 연구에 필수적인 자구체, 자화벽 이미징 장비는 매우 미비한 상황이다. 이와 같은 자성이미징(magnetic domain image), 자화벽(magnetic domain wall)을 연구하는데 있어 가장 핵심적인 장비가 SEMPA(Scanning Electron Microscopy with Polarization Analysis)이다. 일반적으로 SEM의 경우 고 에너지 빔의 전자 빔을 주사 시키고 이때 발생되는 이차 전자의 수를 2차원상의 영역에 따라 달라지는 비로 형상을 측정하게 된다. 이때 전자의 수 뿐만 아니라 이들의 spin polarization을 측정할 수 있다면 형상뿐 만 아니라 표면에서의 스핀 상태를 동시에 측정할 수 있게 된다. 기 개발된 W-filament source를 이용한 SEMPA는 field emission source에 비하여 전자빔의 세기가 약하며 이차 전자의 수도 적어 spin polarization 감도가 현저히 떨어진다. 또한 초고진공($1{\times}10^{-10}torr$)에서 사용할 수 없어 측정시료의 contamination을 방지할 수 없다. 이러한 문제점들을 보안하기 위하여 field emission source를 이용한 FE-SEMPA를 개발 중이며 2차전자의 spin polarization감도를 증가시키기 위하여 monte carlo simulation과 전산시늉등울 통해 스핀 검출기를 개발 및 연구결과를 발표하고자 한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.346-346
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• 2011

최근 들어 나노스케일에서의 자구체(magnetic domain)에 대한 연구가 매우 활발하게 진행되고 있다. 현재 국내에서 자성 나노구조에 대한 연구가 매우 활발하게 진행 되고 있는 반면에 나노자성이미지를 연구 할 수 있는 장비는 매우 미비한 상황이다. 이러한 자성 이미징을 연구하는데 있어 가장 핵심 적인 장비가 SEMPA(Scanning Electron Microscopy with Polarization Analysis)이다. 국내에서 자성나노구조의 자화와 형상을 동시에 측정 할 수 있는 장비는 한국표준과학연구원에서 개발된 W-filament source를 사용한 SEMPA가 유일하다. 일반적으로 SEM의 경우 고에너지 빔의 전자 빔을 주사 시키고 이때 발생되는 이차 전자의 수를 2차원상의 영역에 따라 달라지는 비로 형상을 측정 하게 된다. 이때 전자의 수 뿐만 아니라 이들의 spin polarization을 측정 할 수 있다면 형상뿐 만 아니라 표면에서의 스핀 상태를 동시에 측정할 수 있게 된다. 기개발된 W-filament source를 이용한 SEMPA는 field emission source에 비하여 전자빔의 세기가 약하며 이차 전자의 수도 적어 spin polarization 감도가 현저히 떨어진다. 또한 초고진공(1x10-10torr)에서 사용할 수 없어 측정시료의 contamination을 방지 할 수 없다. 이러한 문제점들을 보안하기 위하여 field emission source를 이용한 FE-SEMPA를 개발 중이다. 본 연구에서는 설계 및 전산시늉등의 연구결과와 진행사항을 발표하고자 한다. 아울러 W-filament를 사용한 SEMPA의 연구결과에 대한 논의를 할 예정이다.

• 한국분말재료학회지
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• 제14권2호
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• pp.101-107
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• 2007

Ultrasonic-milling of metal oxide nanopowders for the preparation of tungsten heavy alloys was investigated. Milling time was selected as a major process variable. XRD results of metal oxide nanopowders ultrasonic-milled for 50 h and 100 h showed that agglomerate size reduced with increasing milling time and there was no evidence of contamination or change of composition by impurities. It was found that nanocomposite powders reduced at $800^{\circ}C$ in a hydrogen atmosphere showed a chemical composition of 93.1W-4.9Ni-2.0Fe from EDS analysis. Hardness of sintered part using 50 h and 100 h powder samples was 399 Hv and 463 Hv, respectively, which is higher than the that of commercial products (330-340 Hv).

• 약학회지
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• 제47권3호
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• pp.135-141
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• 2003

The majority of table salts are bay salts and chemical salts. However, chemical salts are known to have a different composition in biological electrolytes and quality of bay salts are getting worse due to the increasing seawater contamination. These facts may have led to the increasing usage of various health-promoting salts. Bamboo salt was introduced in 1986 as a solution to replace table salts to eliminate those detrimental effects, to promote general health and to treat diseases. Although all bamboo salts from different manufacturers have been used for the same health and medical purposes, each manufacturer utilizes different manufacturing process. The ICP analysis was used to study the changes of elemental contents in a bamboo salt during the manufacturing steps as well as these contents in various bamboo salts and other salts. After the first step, contents of Li and Sr in the bamboo salt were increased in comparison with those in the raw material, bay salt. As the next steps continued, contents of K, Ca and Ba were continuously increased. At the completion of the final step, contents of Mg and P were decreased and those of Cu, Mn and Mo were gradually increased. Bamboo salts contained lower contents of Mg, Al, B, and P, but higher contents of K, Ca, Fe, Cu, Mn, Zn, Li, Ba, Sr and Mo than bay salt.