• 대한방사선치료학회지
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• 제17권2호
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• pp.87-94
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• 2005

목 적 : 공작실에서 block을 제작할 때 중금속이 사용된다. 이때 발생하는 중금속 분진 및 발연(發煙)은 인체에 위해를 준다. 이러한 중금속의 측정과 분석을 통해 심각성을 인식한다. 또한 그에 따른 해결방안을 강구하는 것이 논문의 목적이다. 대상 및 방법 : 논문에 사용되는 기구는 유도 결합 플라즈마 방출분광기이며, 대전 시내 4개 대학병원 방사선 종양학과 공작실(비스무스, 납, 주석, 카드뮴)을 대상으로 하였다. 실험방법은 ppb 단위로 포집하여 비교 분석하고, 체내 및 혈중 중금속 기준치를 통한 공기 중 중금속의 기준치를 계산하며 중금속 임시 기준치를 설정하였다. 결 과 : 지하생활공간 공기 질 관리법에서 정해진 납과 카드뮴의 기준치(24시간 기준)는 $3{\mu}g/m^3$과 $2{\mu}g/m^3$이다. 그리고 비스무스와 주석은 체내 및 혈중 기준치와 다른 중금속 기준치를 통해 $7{\mu}g/m^3$과 $6{\mu}g/m^3$로 정하였다. 대전지역 4개 대학병원 공작실 내부 중금속 측정치를 작업 유무에 따라 비교한다. 비작업 시에는 측정치 대부분이 기준치 이하로 나왔다. 하지만 작업을 하고 있을 경우에는 높은 수치를 나타났다. 또한 차폐체의 구성 비율에 따른 검출 비율의 연관성도 보였다. 결 론 : 작업종사자의 중금속 오염 심각성에 대한 해결방법은 근본적인 부분에서 찾아야 한다. 병원에서는 국소 배기장치의 설치 및 주기적 성능 점검, 보호구 제공 등이 시행되어져야 한다. 또한 작업자는 지속적인 관심과 위생관리, 중금속 오염에 대한 부분을 인식해야 한다. 마지막으로 학회 차원에서 기준치 설정 및 주기적인 측정을 통해 지속적으로 관리를 해야 한다. 그리고 정기적인 특수건강진단의 실시와 같은 근본적인 해결방안을 찾아야겠다.

• Journal of Mechanical Science and Technology
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• 제14권6호
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• pp.645-654
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• 2000

In this paper, low level control algorithms of a metal belt CVT are suggested. A feedforward PID control algorithm is adopted for line pressure based on a steady state relationship between the input duty and the line pressure. Experimental results show that feedforward PID control of the line pressure guarantees a fast response while reducing the pressure undershoot which may result in belt slip. For ratio control, a fuzzy logic is suggested by considering the CVT shift dynamics and on-off characteristics of the ratio control valve. It is found from experimental results that a desired speed ratio can be achieved at steady state in spite of the fluctuating primary pressure. It is expected that the low level control algorithms for the line pressure and speed ratio suggested in this study can be implemented in a prototype CVT.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1539-1541
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• 2002

When did Metal (Au, Al) electrode differently, it is spread already that it is by energy level of electrode difference of electrical conductivity. This paper, experiment manufactures device of Metal/Organic Films/Metal structure using PBDG and I-V properties by electrode analyzed comparison. Also, measure energy level by electrode by propertiesy electrochemistry and studied about electron transfer of organic thin film in LUMO level relation with HOMO level.

• 한국환경과학회지
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• 제17권9호
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• pp.943-947
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• 2008

For the purpose of safety identification, the concentrations of heavy metals in seaweeds collected from Busan Gijang coastal area were investigated. The average concentration of metals had a level of as high as the order of manganese (2.76 ppm)>zinc(2.11 ppm)>copper(0.59 ppm)>arsenic (0.092 ppm)>lead(0.06 ppm)> mercury(0.03 ppm)>cadmium(0.026 ppm). The contents of manganese and zinc were highly detected from P. elliptica, copper and mercury from agar, cadmium from sea mustard and arsenic from wild sea mustard, respectively. The metal contents of seaweeds varied with kinds of samples, but high level for the safety can be found in these samples. Because P. elliptica had shown a clear selectivity for both manganese and zinc, this seaweed could be useful as a bioindicator for these two metal pollution.

• 대한예방한의학회지
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• 제5권1호
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• pp.31-40
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• 2001

Legal permissible limit of herbal drugs metal level in Korea is define 'less 30.0ppm in total(except mineral drugs)' including Pb Hg Cd As Cr Ni etc. This limit has a lot of problems in several factors, that is, not divide hazard and essential elements, not consider high and low toxic effect in each metal, not calculate dose-response relationship and average health behavior in Korean etc. As a that result, It has strong limits and weakness in the basic toxicology and Oriental medicine. To improve and correct these factors, We need to several new approach as like below. It must be radical study following problems in short and middle-long period in the future, toxic metal and essential element must be divide to basic toxicology and also be diverse toxic effect. But mineral drugs that included a amount of severe toxic metals is being used as active prescription drug until now. If toxic, safety and side-effect of metals will be considered, mineral drugs must prohibit instantly or use at least after examined toxic effect. But one of the most important things about herbal drugs contamination, all people and department (government, farmer and trader, oriental medicine doctors and association) will be participate cooperative and collection for preventive or the least contamination in herbal drugs.

• The Plant Pathology Journal
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• 제32권4호
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• pp.329-339
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• 2016

The short-term effects of low-level contamination by heavy metals (As, Cd, Cu, and Pb) on the soil health were examined by analyzing soil nematode community in soils planted with tomatoes. For this, the soils were irrigated with five metal concentrations ([1, 1/4, $1/4^2$, $1/4^3$, and 0] ${\times}$ maximum concentrations [MC] detected in irrigation waters near abandoned mine sites) for 18 weeks. Heavy metal concentrations were significantly increased in soils irrigated with MC of heavy metals, among which As and Cu exceeded the maximum heavy metal residue contents of soil approved in Korea. In no heavy metal treatment controls, nematode abundances for all trophic groups (except omnivorous-predatory nematodes [OP]) and colonizer-persister (cp) values (except cp-4-5) were significantly increased, and all maturity indices (except maturity index [MI] of plant-parasitic nematodes) and structure index (SI) were significantly decreased, suggesting the soil environments might have been disturbed during 18 weeks of tomato growth. There were no concentration-dependent significant decreases in richness, abundance, or MI for most heavy metals; however, their significant decreases occurred in abundance and richness of OP and cp-4, MI2-5 (excluding cp-1) and SI, indicating disturbed soil ecosystems, at the higher concentrations (MC and MC/4) of Pb that had the most significant negative correlation coefficients for heavy metal concentrations and nematode community among the heavy metals. Therefore, the short-term effects of low-level heavy metal contamination on soil health can be analyzed by nematode community structures before the appearance of plant damages caused by the abiotic agents, heavy metals.

• Transactions on Electrical and Electronic Materials
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• 제2권3호
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• pp.12-17
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• 2001

It is shown in the present study that during the HTS (hot temperature storage) test, the metal contamination by impure elements can be highly susceptible to the void formation, leading to the open failure of the power line in the memory device. Such a functional failure associated with the metal contamination was investigated to be dominant in the early stages of the HTS test while the formation of a stress-driven void is mainly observed in the later stages. In particular, it was found that the void formed in the contaminated metal takes on a slit-like shape which has been known to be characteristic of the stress-related voiding. The impure elements leading to the metal degradation were identified to be carbon and oxygen introduced during the metal sputtering process. The experimental works show that the device reliability was significantly improved by reducing the level of such impure elements within metal. It is shown in the present study that during the HTS (hot temperature storage) test, the metal contamination by impure elements can be highly susceptible to the void formation, leading to the open failure of the power line in the memory device. Such a functional failure associated with the metal contamination was investigated to be dominant in the early stages of the HTS test while the formation of a stress-driven void is mainly observed in the later stages. In particular, it was found that the void formed in the contaminated metal takes on a slit-like shape which has been known to be characteristic of the stress-related voiding. The impure elements leading to the metal degradation were identified to be carbon and oxygen introduced during the metal sputtering process. The experimental works show that the device reliability was significantly improved by reducing the level of such impure elements within metal.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 B
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• pp.714-716
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• 1997

In order to prevent the belt from being damaged by metal pieces, we developed multicoil-type metal detection system. This detects the presence of belt clips and position of metal pieces in ores being transported on conveyor belt. In this research, our coil sensor of multicoil-type metal detection system is divided into two parts, exciting part (transmitter coil) and sensing part composed of two receiver coils. Each receiver coil has several coils in the direction of belt width. Multicoil-type metal detection system is operated by supplying a transmitter coil with electric power resources to generate magnetic field, and then the change of magnetic flux resulted from a metal piece on the conveyor be a is induced into sensing coils. We can prevent detector from failing to catch metal pieces due to high threshold level produced by steel belt clips and male the sensitivity of belt-width direction uniform by using multicoil-type metal detection system. Besides, this developed system can recognize precise position and size of metal piece. The experiments shows that our multicoil-type metal detection system has better performances than the conventional metal piece detector.

• 대한예방한의학회지
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• 제3권2호
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• pp.151-170
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• 1999

This study was to investigate the metal accumulation from SipJeonDaeBo-Decoction to rat blood of Sprague Dawley. 1. There were no significance in body weight, water dose feed ingestion quantity, liver, kidney, brain, bone weights between the control and the experimental groups. Under the experiment with drinking waters was no metal ${\sim}\;0.65mg/L$ detected. Metal level within feed found 0.0001-376.983mg/kg. 2. In the pack of SipJeonDaeBo-decoction, there detected no metal ${\sim}2.086mg/L$ 3. After P.O(per os) SipJeonDaeBo-decoction, As is detected $2.390{\pm}0.812mg/kg$ in blood; Cd $0.001{\pm}0.001mg/kg$, Co $0.003{\pm}0.001mg/kg$, Cr $0.432{\pm}0.234mg/kg$, Cu $1.013{\pm}0.373mg/kg$, Fe $426.293{\pm}114.842mg/kg$, no Hg, Mn $0.109{\pm}0.082mg/kg$, Ni $0.122{\pm}0.068mg/kg$, Zn $3.584{\pm}1.270mg/kg$. 4. The concentration of Hazardous heavy metal (As, Cd, Co, Cr, Hg, Ni, Pb) within blood control group is searched $0.488{\pm}0.138\;mg/l$; experiment I group $0.432{\pm}0.080mg/l$, experiment II group $0.588{\pm}0.213mg/l$. In the concentration of non hazardous heavy metal(Cu, Fe, Mn, Zn) control group $101.409{\pm}6.832mg/l$; experiment I group $96.062{\pm}5.732\;mg/l$, experiment II group $125.139{\pm}044.820mg/l$. 5. Correlation among every metal in blood Zn and Cr was 0.87956 ; Cd and As -0.02316, Pb and As -0.08738, Ni and As 0.07824, Mn and As 0.07824, Mn and Cd 0.04999. Briefly under the injection of SipJeonDaeBo-decoction, this study was defined within safety in blood level by P.O. during 10 days.

• 한국지하수토양환경학회지:지하수토양환경
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• 제16권4호
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• pp.23-30
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• 2011

Risk based pollution level of Pb and Cd in metal contaminated soils depending on physicochemical properties of soil in a target site was assessed using biotic ligand model. Heavy metal activity in soil solution defined as exposure activity (EA) was assumed to be toxic to Vibrio fischeri and soil organisms. Predicted effective activity (PEA) determined by biotic ligand model was compared to EA value to calculate risk quotient. Field contaminated soils (n = 10) were collected from a formes area and their risk based pollution levels were assessed in the present study using the calculated risk quotient. Concentrations of Pb determined by aqua regia were 295, 258, and 268 mg/kg in B, H and J points and concentrations of Cd were 4.73 and 6.36 mg/kg in G and I points, respectively. These points exceeded the current soil conservation standards. However, risk based pollution levels of the ten points were not able to be calculated because concentrations of Pb and Cd in soil solution were smaller than detection limits or one (i.e., non toxic). It was because heavy metal activity in soil solution was dominant toxicological form to organisms, not a total heavy metal concentration in soil. In addition, heavy metal toxicity was decreased by competition effect of major cations and formation of complex with dissolved organic carbon in soil solution. Therefore, it is essential to consider site-specific factors affecting bioavailability and toxicity for estimating reliable risk of Pb and Cd.