• 한국산업보건학회지
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• 제24권3호
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• pp.353-358
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• 2014

Purpose: This study was conducted to evaluate desorption efficiency and storage stability on activated carbon acquired form domestic market. Materials: Mixture of acetone, benzene, normal hexane and toluene was injected on four types of charcoal 100 mg. After overnight, charcoal was desorbed by carbon disulfide $1m{\ell}$ and analyzed by gas chromatography with flame ionization detector. Results: Desorption efficiency of benzene, normal hexane and toluene in charcoal tubes were 95% ~ 105%. But desorption efficiency of acetone in charcoal tubes was below 75% and different from types of charcoal. The more injected amount of acetone on charcoal showed higher desorption efficiency. Acetone injected on charcoal tubes migrated from front section into back section after 10 days storage at room temperature. Conclusions: Desorption efficiency and storage stability of activated carbon acquired from domestic market was good for benzene, normal hexane and toluene. The activated carbon acquired from domestic market has ability to be used as sampling media.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2006년도 가을 학술발표논문집 Vol.33 No.2 (D)
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• pp.85-89
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• 2006

센서네트워크에는 한 가지 종류의 센서만을 사용하는 것이 아니라 여러 가지 종류의 센서를 하나의 네트워크에 연결하여 한 번에 여러 종류의 센서의 질의를 수행할 수 있어야 한다. 이 경우에 다양한 센서가 부착된 네트워크에서 한 가지 종류의 센서에 대한 질의를 수행할 경우 해당되는 센서를 포함하지 않는 센서에 대해서도 질의를 수행해야 한다. 본 논문에서는 여러 종류의 센서가 부착된 센서네트워크에서 라우팅 테이블을 이용하여 질의를 최적화하는 방법을 제안한다. 센서노드의 라우팅 테이블에는 그 센서가 질의명령어를 보내고 받아야 하는 센서노드에 대한정보를 포함한다. 자식노드에 명령어를 보낼 경우 하위노드에서 질의하는 센서의 종류가 없을 경우에도 명령어를 보내야 한다. 이 경우 하위 자식노드에 원하는 센서의 종류에 관한 정보를 포함하면 센서의 종류에 따라서 불필요한 명령어의 수행을 줄일 수 있도록 하였다. 이 방법은 ATmega128 CPU를 장착한 Nano-Q+ 시스템에서 구현되었다.

• 마이크로전자및패키징학회지
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• 제13권4호
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• pp.57-63
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• 2006

칩 스택 패키지의 삼차원 interconnection에 적용을 위해 폭 $75{\sim}10\;{\mu}m$, 길이 3mm의 트랜치 비아에 대해 전기도금전류밀도 및 전류모드에 따른 Cu filling 특성을 분석하였다. 직류모드로 $1.25mA/cm^{2}$에서 Cu filling한 경우, 트랜치 비아의 폭이 $75{\sim}35{\mu}m$ 범위에서는 95% 이상의 높은 Cu filling ratio를 나타내었다. 직류 전류밀도 $2.5mA/cm^{2}$에서 Cu filling한 경우에는 $1.25mA/cm^{2}$ 조건에 비해 열등한 Cu filling ratio를 나타내었으며, 직류모드에 비해 펄스모드가 우수한 Cu filling 특성을 나타내었다.

• 한국전자파학회논문지
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• 제25권2호
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• pp.251-254
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• 2014

본 논문에서는 주파수 도약 신호를 고속 병렬처리 구조로 설계하여 추출하는 기법에 대해 연구하였다. 주파수 도약 시스템은 반송파 주파수를 무작위한 것으로 보이는 패턴으로 변형시키기 때문에 고정 신호와는 달리 신호를 탐지하기 어렵고, 분석에 많은 시간이 소요되는 특성을 가진다. 이를 해결하기 위해 주파수 도약 신호를 분석하는 방법을 고속병렬처리 기법을 적용하여 설계하였다. 병렬처리를 위해 GPU를 사용하는 CUDA를 사용하였고, 단일처리 사용 결과와의 성능 평가 결과를 비교하였다. 그 결과, 단일처리 대비 연산 수행 속도 면에서 약 8.53배 성능이 향상됨을 확인하였다.

• 한국환경보건학회지
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• 제28권1호
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• pp.41-49
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• 2002

Recently, pilot studies showed an evidence of reduction of airborne hexavalent chromium, Cr(VI), on PVC filter during air sampling and storage. However, the information on this in the field was limited. Thus, we studied the reduction behaviors of airborne Cr(VI) on PVC filters during sampling and storage at three field electroplating operations. Regression between sampling time and the reduction (ratio of Cr(VI) to total Cr concentrations) was not statistically significant (p>0.05). However, the reductions in samples collected for 240 ～ 340 minutes were significantly higher than those for 30 - 60 minutes. On the other hand, another experiment showed a good correlation (r=0.96) between sampling time and the reduction without an exceptional value. Storage temperature was not a factor affecting the reduction of Cr(VI) collected on PVC filter. The loss of Cr(VI) samples stored in alkali solution (2% NaOH/3% Na$_2$CO$_3$) was significantly lower than that stored in vial according to NIOSH method (p<0.05). Thus, dipping Cr(VI) samples into alkali solution was a storage method to minimize tile reduction.

• 한국환경보건학회지
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• 제30권3호
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• pp.259-263
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• 2004

This study was performed to investigate airborne formaldehyde concentration in preschool facilities. Arithmetic mean of indoor formaldehyde concentration in urban area was 34.9 ppb(Geometric mean 24.4 ppb) whereas outdoor concentration was 21.5 ppb(GM 11.9 ppb). In rural area, formaldehyde concentrations were 36.4 ppb(GM 28.7 ppb), 4.1 ppb(GM 4.1 ppb), respectively. There is no statistical significance between the formaldehyde concentrations of urban classrooms and those of rural area. We verified that the distribution of airborne formaldehyde concentration was log-normal characteristic using Shapiro and Wilk test. The 6.7% of urban indoor samples was exceeded the domestic standard limit of indoor air quality. From our study and other study, we concluded that the major emission sources of formaldehyde in preschool facilities was in indoor rather than outdoor.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 춘계학술대회
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• pp.189-192
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• 2016

1999년 2월에 "상품권법"이 폐지된 후 별도의 등록이나 허가 절차 없이 인지세만 납부하면 누구나 상품권 발행이 가능하게 되었다. 최근 모바일 기기 및 모바일 앱의 사용이 보편화되면서 모바일 상품권 시장도 폭발적으로 증가하게 되었다. 특히 손쉽게 전달 및 선물이 가능하다는 이점으로 인해 케이크나 커피 같은 먹거리뿐만 아니라 대리운전, 결혼 정보 서비스 등 다양한 분야에서도 모바일 상품권을 출시하고 있다. 앞으로의 상품권 시장은 지류상품권 중심에서 모바일 상품권 중심으로 개편될 것으로 사료된다.

• 한국산업보건학회지
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• 제21권2호
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• pp.99-102
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• 2011

Objectives: Acetone/triacetine method for clearing cellulose ester membrane (CEM) filter has been a popular method for air-borne asbestos analysis. However, as a weakness of this method, it is time consuming to analyses asbestos samples after sampling. Crystalclear method can be used to analyses asbestos samples promptly after sampling. Although a strength of crystal clear method exists, there was little valid studied for the method. This study was conducted to compare acetone/triacetine method with crystalclear one for analysing asbestos sample. Methods: Test samples made in three different concentration ranges(low, medium and high concentration) were analysed by phase contrast microscopy after acetone/triacetine and crystalclear method treatment respectively. Results: We did not find statistical difference in analysed results between two methods, which were conducted in three different concentrations ranges. Conclusions: We concluded that crystalclear method can be used as clearing method for air-borne asbestos analysis instead of acetone/triacetine method.

• 한국산업보건학회지
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• 제22권3호
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• pp.209-216
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• 2012

Objectives: Polyurethanes are usually formed by the reactions of liquid diisocyanate components with liquid polyol resin components. Although polyurethanes have advantageous properties, such as their versatility, the manufacturing process generates diisocyanates, which can cause asthma and respiratory irritation in exposed workers. This study compared the differences in diisocyante concentrations between two different (molded foam and slabstock foam) polyurethane foam manufacturing methods. Materials and Methods: Active samples and direct reading samples of diisocyanates (MDI, TDI) were collected in five polyurethane foam manufacturing companies. Results: Workers' exposure concentrations of diisocyanate (GM: 4.078 ppb, range: 1.190~23.770 ppb) in a slabstock foam manufacturing company were much higher than those (GM: 0.011 ppb, range: 0.001~0.055 ppb) in molded foam manufacturing companies. The results of the direct reading samples of diisocyanate indicated that the rapid reaction zone of the slabstock foam processes emitted large amounts of diisocyanates. Conclusions: The exposure levels of diisocyanates for all molded foam workers were much lower than the occupational exposure standard (5 ppb); however, exposure levels for many slabstock foam workers exceeded the standard.

• 한국산업보건학회지
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• 제19권2호
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• pp.81-87
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• 2009

Final purpose of this study was designed to develop the quality control(QC) sample for proficiency analytical testing of asbestos. This study consisted of two parts; first, development of manufacturing apparatus and sample preparing procedure for asbestos quality control(QC) sample: second, validation of the QC samples made by our developed method as asbestos proficiency analytical testing sample. The main results of the first part research are as followed We developed the apparatus for manufacturing the asbestos QC sample, consisted of filter hold, filter holder manifolder, vacuum system, and vacuum pump. The most proper filter of making the QC samples was a cellulose ester membrane filter with 25 mm diameter, pore size 0.8 um. And we presented the optimal procedure for preparing the asbestos QC sample by using the developed apparatus. We will verify the manufactured asbestos QC samples by this method, and present the validation results to confirm the reliability as a asbestos QC sample in next paper.