• 한국터널지하공간학회 논문집
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• 제17권1호
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• pp.1-9
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• 2015

본 논문은 터널 조명 시스템을 적절하게 운영하기 위하여, 터널 내부/외부의 휘도를 측정하는 영상휘도계의 개발 내용을 소개한다. 터널을 측정하는 국제규격 CIE88의 L20법 및 광막법이 구현 가능하도록 개발하였으나 현재 주로 적용되는 L20법을 위주로 실험하였다. 독립적 운영을 위하여 컴퓨터가 내장되었으며 외부와는 이더넷 통신으로 연결된다. 내부에 자동 온도조절 기능과 앞면유리의 열선과 와이퍼 시스템이 구축되었다. 정확한 휘도 측정을 위하여 노출시간과 휘도량에 따른 비선형 특성을 보정하는 수식이 적용되었다. 개발된 휘도계의 공인기관 교정결과는 1%미만의 오차를 보여주었다. 개발된 휘도계를 이용하여 실제 터널에서 실험을 하였고, 실험결과 기준 휘도계측기들과 유사한 특성을 보였으며, 매우 안정적으로 작동함을 볼 수 있었다. 다만, 부분적 고휘도로 인한 센서 포화에 의한 측정오차를 해결하는 과제는 남아 있다.

• 대한환경공학회지
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• 제30권3호
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• pp.278-285
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• 2008

본 연구는 건조, 퇴비화, 고화로 전처리된 유기성오니와 생활폐기물을 각각 2 : 8과 4 : 6으로 혼합하여 매립할 경우 매립지 환경에 미치는 영향을 평가하고 유기성오니의 직매립금지 조치이후 적정 처리방안을 모색하기 위하여 실시하였다. 고화오니는 약 1,800$\sim$2,500 L의 가장 활발한 가스발생량을 나타내어 건조 및 퇴비오니의 1,150$\sim$1,650 L 보다 높았다. 악취 중 황화수소 최대농도는 Composted-20(약 80 ppmv) > Composted-40(약 55 ppmv) > Dried-20(약 30 ppmv) > Dried-40 $\fallingdotseq$ Solidified-20 $\fallingdotseq$ Solidified-40 (약 20 ppmv)순으로 나타났다. 침출수 발생초기 BOD$_5$는 Composted-40에서 약 38,000 mg/L으로 가장 높게 나타났으며, Dried-40이 약 28,000 mg/L, Dried-20이 약 26,000 mg/L, Composted-20과 Solidified-40이 21,000 mg/L를 나타내었으며, Solidified-20이 17,000 mg/L로 가장 낮았다. 570일차 고화오니의 BOD$_5$는 300$\sim$500 mg/L, 건조 및 퇴비오니는 2,000$\sim$3,500 mg/L의 농도를 나타내었다. 고화처리된 오니를 생활폐기물과 혼합할 경우 빠른 분해로 매립가스가 가장 많이 발생되었으며, 악취 및 침출수 농도도 가장 낮게 나타나 유기성 고화처리 후 매립쪽으로 유도되는 것이 가장 바람직하였다. 최근 매립가스 재이용(CDM) 사업을 수행하는 매립장에 대해서는 직매립을 허용하고 있으므로 유기성오니 매립시에는 반드시 생활폐기물과 혼합하는 것이 필요하며, 메탄가스를 보다 많이 생산하기 위해서는 고화오니를 혼합매립하는 것이 가장 유용할 것으로 판단된다.

• 분석과학
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• 제25권3호
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• pp.190-196
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• 2012

납에 의한 노출에 대한 평가에는 주로 전혈 중 납을 사용하고 있으나 전혈 중 납은 납의 단기 노출에 대한 정보만을 제공한다는 단점이 있다. 납 노출의 만성적 노출지표인 혈장 중 납을 분석하기 위해서는 수 ng/L의 극미량 분석이 요구되어 납의 만성지표로서의 효용성 검증에 어려움이 있다. 본 연구에서는 납 노출 근로자의 만성 노출 지표로서 혈장 중 납을 분석하기 위하여 유도결합플라즈마 질량분석법을 정립하였다. 외부환경으로부터의 오염을 최소화시키기 위해 class 1,000 수준의 청정실을 설치한 후 가동 전과 후의 부유 분진량을 확인한 후 극미량 시료 분석을 수행하였다. 표준 우태아 혈청을 이용하여 표준물 첨가법에 의한 표준편차를 이용하여 계산한 최소검출한계는 4.3 ng/L, 최소정량한계는 12.2 ng/L이었으며, 신호-대-잡음 비로 계산한 최소검출한계는 7.0 ng/L, 최소정량한계는 22.1 ng/L이었다. 20 ng/L부터 2,000 ng/L 농도 범위에서 정밀도는 4% 이내였으며, 우태아 혈청에 20-2,000 ng/L의 농도로 첨가하여 계산한 회수율은 92.3-101.3%로 양호한 결과를 얻었다. 본 연구에서 제시한 방법을 사용하여 납 노출근로자의 혈장 및 혈청 중 납 분석이 가능하였으며 이를 통해 납의 만성노출에 대한 조사가 가능할 것으로 판단된다.

• ETRI Journal
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• 제31권1호
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• pp.68-70
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• 2009

In this letter, a parametric analysis of the Fresnel-field antenna measurement method is performed for a square aperture. As a result, the optimum number of Fresnel fields for one far-field point is guided as $M_{opt}=N_{opt}=D^2/{\lambda}R+5$, where D is the antenna diameter, ${\lambda}$ is the wavelength, and R is the distance between the source antenna and the antenna under test. For the aperture size 5 ${\leq}$ $L_x/{\lambda}$ ${\leq}$ 20, the tolerable distances for gain errors of 0.5 dB and 0.2 dB can be guided as $R_{0.5\;dB}$ ${\approx}$ $1.2Lx/{\lambda}$ and $R_{0.2\;dB}$ ${\approx}$ $2.0L_x/{\lambda}$, where $L_x$ is the lateral length of the square aperture. The tolerable distances for 20 ${\leq}$ $L_x/{\lambda}$ ${\leq}$ 200 are also proposed. This measurement guideline can be fully utilized when performing the Fresnel-field antenna measurement method.

• 한국공간구조학회지
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• 제7권4호
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• pp.14-20
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• 2007

• 조명전기설비학회논문지
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• 제26권1호
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• pp.1-7
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• 2012

As the standard lighting required in the threshold zone of a road tunnel is determined by the enough contrast. Lighting design, therefore, must be determined by the calculation method of threshold luminance based on the adaptation luminance of the driver approaching the tunnel. The veiling luminance and the luminance in the access zone were measured at different time and in different weather using the veiling luminance method, a kind of perceived contrast methods, and the L20 method when the range of vision was 20 degrees. On the basis of the measured data each threshold luminance was calculated and its results were analyzed.

• 전기전자학회논문지
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• 제20권3호
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• pp.226-234
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• 2016

전기 저항 단층촬영법(ERT)은 대상체 내부 단면의 저항률 분포를 추정하고 이를 영상화하는 기술이다. ERT의 영상복원은 매우 비정치성이 강한 역문제의 일종으로 의미있는 영상을 얻기 위해서는 조정기법이 사용된다. 대표적으로 l2-norm 조정기법, l1-norm 조정기법, Total Variation 조정기법이 사용되며, 조정기법에 따라 ERT의 영상복원 성능이 달라진다. 즉, 상황에 맞는 적절한 조정기법의 사용은 ERT 영상 복원을 개선할 수 있다. 따라서, 본 논문에서는 모의실험을 통하여 상황에 따른 세 가지 조정기법의 영상복원 성능을 비교하였다.

• Journal of the Korean Wood Science and Technology
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• 제36권2호
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• pp.46-55
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• 2008

This study assesses the formaldehyde and TVOC emissions from bio-composites with attached fancy veneer manufactured using wood flour and polypropylene (PP) measured using the Field and Laboratory Emission Cell (FLEC) method and 20 L small chamber method. To determine and compare the effects of the adhesive, samples were prepared with different manufacturing methods. In the FLEC result, the formaldehyde emission level of the bio-composites with attached veneer by hot-press was the lowest than pure bio-composite and bio-composite attached veneer using adhesive. The TVOC emission levels are similar to the formaldehyde emission. The TVOC emission level is very low in all of the samples except fancy veneer that is attached with bio-composites using adhesive. The TVOC emission varies depending on how attaching fancy veneer. The results of the 20 L small chamber method were very similar to those obtained with the FLEC, but the correlation was not perfect. However, the FLEC method requires a shorter time than the 20 L small chamber method to measure the formaldehyde and TVOC emissions. The internal bonding strength exceeded the minimum value of $0.4N/mm^2$ specified by the KS standard. All of the bio-composites with attached veneer satisfied the KS standard.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1547-1553
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• 2011

An effective analytical method of gas chromatography/mass spectrometry (GC/MS) was developed for the rapid determination of essential oils in the crude extract of Acorus species (Acorus gramineus, Acorus tatarinowii, and Acorus calamus). Major phenypropanoids (${\beta}$,${\alpha}$-asarone isomers, euasarone, and methyleugenol) and ${\beta}$-caryophyllene in Acorus species were used as marker compounds and determined for the quality control of herbal medicines. To extract marker compounds, various extraction techniques such as solvent immersion, mechanical shaking, and sonication were compared, and the greatest efficiency was observed with sonication extraction using petroleum ether. The dynamic range of the GC/MS method depended on the specific analyte; acceptable quantification was obtained between 10 and 2000 ${\mu}g/mL$ for ${\beta}$-asarone, 10 and 500 ${\mu}g/mL$ for ${\alpha}$-asarone, 10 and 200 ${\mu}g/mL$ for methyleugenol, and between 5 and 100 ${\mu}g/mL$ for ${\beta}$-caryophyllene. The method was deemed satisfactory by inter- and intra-day validation and exhibited both high accuracy and precision, with a relative standard deviation < 10%. Overall limits of detection were approximately 0.34-0.83 ${\mu}g/mL$, with a standard deviation (${\sigma}$)-to-calibration slope (s) ratio (${\sigma}$/s) of 3. The limit of quantitation in our experiments was approximately 1.13-3.20 ${\mu}g/mL$ at a ${\sigma}$/s of 10. On the basement of method validation, 20 samples of Acorus species collected from markets in Korea were monitored for the quality control. In addition, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were performed on the analytical data of 20 different Acorus species samples in order to classify samples that were collected from different regions.

• The Korean Journal of Physiology
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• 제11권2호
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• pp.45-50
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• 1977

The maximum voluntary ventilation (MVV) is one of the most widely used pulmonary function test, but its measuring method was very difficult and unreliable. However, it is need to get more easy and simple measuring method of MVV. Therefore, this study was attempted to get more easy and simple measuring method of MVV by means of the forced expiratory volume $(FEV_{T})$. The young and healthy 1,000 Korean students(592 male and 408 female) were cheesed for this purpose and whose ages were from 8 to 20 years. A spirometer (9L, Collins Co.) was used for the MVV and FEV, and they were measured 3 times at standing position, and the highest value was used. In the measurements, the subjects for MVV were asked for the breath as fast and deeply as possible for 12 seconds, and for FEV were asked for the rapid and forceful exhalation after a maximal inhalation (forced expiratory curve). In the FEV measurements toward the end of the expiration, the subjects were exhaused to continue the effort until no further gas was expired. During these measurements, the investigator stood by the subject to give a constant encouragement. FEV were calculated in the volume exhaled during the one-half $(FEV_{0{\cdot}5,}\;ml)$, the first second $(FEV_{1{\cdot}0,}\;ml)$ and the percentage of the total vital capacity exhaled during the one-half second $(FEV_{0{\cdot}5,}\;%)$. The results are summarized as follows: 1) The values of MVV were increased linearly with ages until 20 in both sexes. The values of male at the age of 20 was $168.2{\pm}2.5L/min$, and female at the age of 17 was $112.3{\pm}3.0L/min$, respectively. 2) The values of FEV (ml) were increased linearly with ages until 20 in both sexes. The values of $FEV_{0{\cdot}5}$ were $2,797{\pm}65.7ml$ in the male of 20 years and were $2,088{\pm}54.6ml$ in the female of 17 years, and of $FEV_{1{\cdot}0$ were $4,119{\pm}68.2ml$ in the male of 20 years and were $2,897{\pm}65.9ml$ in the female of 17 years, respectively. 3) The correlation coefficients between MVV and $FEV_{0{\cdot}5}\;or\;FEV_{1{\cdot}0$ (ml) were 0.82 or 0.85 in the male, and 0.77 or 0.79 in the female, respectively. 4) The prediction formulae for MVV to be derived from above results were: For male: MVV (L/min) =7.19+$0.05{\times}FEV_{0\cdot5}(ml)$, MVV (L/min)=11.25+$0.04{\times}FEV_{1\cdot0}(ml)$ For female: MVV (L/min)=16.03+$0.05{\times}FEV_{0\cdot5}(ml)$, MVV (L/min)=9.47+$0.03{\times}FEV_{1\cdot0}(ml)$.