• 한국환경보건학회지
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• 제33권2호
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• pp.166-173
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• 2007

이 연구에서 환원성 황 화합물의 시간적, 공간적 분포 패턴들이 매립과정에 크게 영향 받는 지역에서 조사되었다. 이러한 측정 연구에 기초하여 환원성 황 화합물이 이산화황으로 변환되는 광화학적 작용 규모를 광화학적 상자모델을 이용하여 평가하였다 이 연구는 2004년 3월에서 12월까지 대기 중 환원성 황 화합물 농도를 군산시의 매립장 내부와 인근에서 평가했다. 환원성 황 화합물의 분포가 일반적으로 $H_2S$, DMS, 또는 DMDS들이 대부분인 반해, 그 패턴들은 시료채취 지역과 기간에 따라 다양했다. 군산 매립장에서 $H_2S$, DMS는 연구기간 동안 가장 높은 농도를 나타냈다. 이 지점에서 DMS의 농도는 매립 과정 뿐만 아니라 해양 오염원에 영향을 받는다고 사료되었다. 모든 환원성 황 화합물이 아황산가스의 광화학적 부산물에 대한 상대적 기여도를 비교할 때, 세가지 환원성 황 화합물(DMDS, $H_2S$, 그리고 DMS)이 가장 중요한 물질로 조사되었다.

• 분석과학
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• 제23권1호
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• pp.24-35
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• 2010

본 연구에서는 GC-PFPD와 열탈착 분석기법을 이용한 환원 황화합물(reduced sulfur compounds: RSC)에 대한 열탈착 검량방식의 시간적 재현성을 기존의 외부 검량기법에 덧붙여, 내부표준시료 기법을 연계하여 평가하고자 하였다. 이를 위하여, 4종류의 악취성 황화합물질($H_2S$, $CH_3SH$, DMS, DMDS)과 이들에 대한 내부 표준시료로 CS2를 준비하였다. 이들 표준시료는 저농도(10, 20, 50, 100 ppb)와 고농도 그룹(100, 200, 500, 1000 ppb)을 대표할 수 있게 넓은 범위로 준비하였다. 그리고 외부검량(external calibration)방식의 분석 결과를 부피고정방식(fixed standard volume: FSV)과 농도고정방식(fixed standard concentration: FSC)로 비교하였다. 또한, 2차적으로 FSV 방식의 결과에 외부 및 내부 검량기법을 동시에 적용하여 검량방식의 경시변화(안정도)를 평가하였다. 본 실험의 결과, 감도에 대한 경시변화는 FSC 방식에 비해 FSV 방식에서 작게 나타났다. 따라서 RSC 분석에서 FSV방식이 경시변화를 줄여주는데 상대적으로 효과적이라는 것을 알 수 있었다. 2차적으로 FSV 방식의 결과에 대해 외부 및 내부방식의 감도(기울기 값)를 비교하였다. 이러한 비교를 상대표준편차(RSD)값으로 평가하면, GC-PFPD-TD 시스템의 감도가 비교적 강한 경시변화를 보인다는 것을 알 수 있다. 따라서 이러한 분석기법의 시간적 재현성을 확보하기 위해서는 여러 가지 검정노력이 필요한 것으로 사료된다.

• 한국대기환경학회지
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• 제20권5호
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• pp.647-654
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• 2004

This study examines the local oxidation chemistry of reduced sulfur compounds (RSC) in the urban air. The chemical conversion of RSC (such as DMS, $CS_2,\;H_2S,\;DMDS,\;and\;CH_3SH)\;to\;SO_2$ was modeled using a photochemical box model. For our model prediction of the RSC oxidation, measurements were carried out from an urban monitoring station in Seoul (37.6$^{\circ}$N, 127.0$^{\circ}$E), Korea for three separate time periods (Sep. 17~18; Oct 23; and Oct. 27~28, 2003). The results of our measurements indicated that DMS and $H_2S$ were the dominant RSC with their concentrations of 370${\pm}$140 and 110${\pm}$60 pptv, respectively. The conversion of DMDS to $SO_2$ can occur efficiently in comparison to other RSC, but it is not abundant enough to affect their cycles. The overall results of our study indicate that the photochemical conversion of the RSC can contribute ≶ 20% of the observed $SO_2$.

• Industrial Engineering and Management Systems
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• 제14권1호
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• pp.44-57
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• 2015

In recent years, for the purpose of solving the problem regarding environment protection and resource saving, certain measures and policies have been promoted to establish a reverse supply chains (RSCs) with material flows from collection of used products to reuse the recycled parts in production of products. It is necessary to analyze behaviors of RSC members to determine the optimal operation. This paper discusses a RSC with a retailer and a manufacturer and verifies the behavior strategies of RSC members which may change over time in response to changes parameters related to the recycling promotion activity in RSC. A retailer takes two behaviors: cooperation/non-cooperation in recycling promotion activity. A manufacturer takes two behaviors: monitoring/non-monitoring of behaviors of the retailer. Evolutionary game theory combining the evolutionary theory of Darwin with game theory is adopted to clarify analytically evolutionary outcomes driven by a change in each behavior of RSC members over time. The evolutionary stable strategies (ESSs) for RSC members' behaviors are derived by using the replicator dynamics. The analysis numerically demonstrates how parameters of the recycling promotion activity: (i) sale promotion cost, (ii) monitoring cost, (iii) compensation and (iv) penalty cost affect the judgment of ESSs of behaviors of RSC members.

• 한국대기환경학회지
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• 제29권5호
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• pp.615-624
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• 2013

In this study, the emission patterns of reduced sulfur compounds (RSC) were investigated using four different types of food samples (boiled egg, milk, canned meat and strawberry) between fresh and decaying stages. To this end, the concentrations of RSCs were measured at storage days of 0, 1, 3, 6, and 9 under room temperature. Four sulfur compounds ($H_2S$, $CH_3SH$, DMS and DMDS) were selected as target compounds along with two reference compounds ($CS_2$ and $SO_2$). Their concentrations were quantified using GC-PFPD equipped with thermal desorption (TD) system. The boiled egg showed the highest concentration of $H_2S$ (3,655 ppb) at D-1, while $CH_3SH$ reached its maximum value of 64.4~78.5 ppb after 3 days. In milk samples, concentration of $CH_3SH$, DMS, and DMDS went up to 487, 16.3, and 578 ppb, respectively with the progress of decay (D-9). In case of canned meat, concentration of $H_2S$ and $CH_3SH$ peaked in the beginning (D-0) such as 345 and 66.6 ppb. In case of strawberry, $CH_3SH$ and DMDS showed the maximum concentrations 135 and 50.5 ppb at D-1, respectively. The olfactometry dilution-to-threshold (D/T) ratio by air dilution sensory (ADS) test showed similar patterns when sum of odor intensity (SOI) was derived via conversion of odorant concentration data. The results of this study confirm that the time of strong RSC emissions is distinguished for each food type between fresh (e.g., strawberries) and decaying conditions (e.g., milk).

• 한국대기환경학회지
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• 제28권3호
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• pp.306-315
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• 2012

In this study, storage stability of reduced sulfur compounds ($H_2S$, $CH_3SH$, DMS, $CS_2$, and DMDS) and $SO_2$ in sampling bags was investigated in terms of two contrasting storage approaches between forward (F) and reverse (R) direction. The samples for the F method were prepared at the same time and analyzed sequentially through time. In contrast, those of reverse (R) method were prepared sequentially in advance and analyzed all at once upon the preparation of the last sample. In addition, relative performance between two different bag materials (PVF and PEA) was also assessed by using 100 ppb standard. The response factors (RF) of gaseous RSC samples were determined by gas chromatography/pulsed flame photometric detector (GC/PFPD) combined with air server (AS)/thermal desorber (TD) system at storage intervals of 0, 1, and 3 days. There is no statistical difference in all RSCs between two storage methods. However, the results of relative recovery indicated 2.58~12.8% differences in compound type between the two storage methods. Moreover, loss rates and storage stability of $H_2S$ and $SO_2$ were considerably affected by bag materials than any other variables. Therefore, some considerations about storage methods (or bag material types) for sulfur compounds are needed if stored by sampling bag method.

• 한국대기환경학회지
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• 제27권3호
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• pp.281-290
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• 2011

In this study, a series of experiments were carried out to measure temporal stability of reduced sulfur compounds (RSCs) in Tedlar bag samples as a function of elapsed storage time. To this end, temporal variability of 4 RSC standard gases ($H_2S$, $CH_3SH$, DMS, DMDS) was measured up to 29 days. For the purpose of comparison, RSC samples were stored in both individual and mixed state. In the case of mixed standard, samples were also examined to allow comparison between light and dark condition. Then results of $CH_3SH$ data were the most stable with the least change in its concentrations through the end of exps (29 days). When compared with previous studies, the extent of stability appeared to be influenced by the initial concentration levels of samples. When the patterns were compared between individual and mixture samples, differences were not significant in the case of $H_2S$ and DMS. The effects of light conditions on temporal stability were seen to be fairly sensitive on most RSC other than $H_2S$. The results of our study confirm that the stability of RSC storage is affected by their involvement in photochemical reactions.

• 분석과학
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• 제23권4호
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• pp.347-356
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• 2010

도심 지역의 하수관거에서 발생하는 주요 악취성분들의 발생특성 및 배출경향을 평가하였다. 하수관거에서 발생하는 총 6 가지의 지정 악취물질들($H_2S$, $CH_3SH$, DMS, DMDS, $CH_3CHO$, $NH_3$)을 주 대상으로 선정하여 조사를 실시하였다. 건조한 조건과 습한 조건을 유지하는 2개의 비교대상 하수관거에서 악취시료를 채취하였다. 측정한 악취물질들을 농도기준의 절대값과 이를 경험식에 주입하여 산출한악취지수(OI, SOI)를 동시에 활용하는 방식으로 비교분석을 하였다. 실험 결과, 전체 분석 성분 중 $CH_3SH$, $H_2S$, DMS 등의 환원황화합물(reduced sulfur compounds: RSC) 성분들이 악취세기에 큰 영향을 미치는 것으로 나타났다. 또 연구결과들을 전체적으로 종합해 보면, 주요 악취성분들의 일간 발생경향은 식생활 및 배수 등의 인간활동과 어느 정도 연관성을 띄고 있음을 알 수 있었다.

• 한국대기환경학회지
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• 제27권4호
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• pp.454-459
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• 2011

In this study, the recovery rate of Tedlar bag (T) sampler was investigated in comparison to polyester aluminum bag (P) sampler. To derive the comparative data sets for the relative performance between different samplers, a series of calibration experiments were performed by using 1 ppb standard of four offensive reduced sulfur compounds (RSC) odorants ($H_2S$, $CH_3SH$, DMS, and DMDS) along with $SO_2$ and $CS_2$. All the analysis was made by gas chromatography/pulsed flame photometric detector (GC/PFPD) combined with air server/thermal desorber (AS/TD). The measurement data were obtained by loading gaseous standards (1 ppb) at 3 injection volumes (250, 500 and 1,000 mL) at three intervals (0, 24 and 72 hrs). The recovery rates (RR) of P sampler were computed against the slope values of T sampler. According to our analysis, P sampler exhibits slightly enhanced loss relative to T, especially with light RSCs ($H_2S$ and $CH_3SH$). At day 0, RR for the two were 88 and 85%, respectively. Such reduction proceeded rather rapidly in the case of $H_2S$ through time. However, P sampler was more stable to store $SO_2$ unlike others. Despite slightly reduced recovery, P sampler appears as a good replacement of T sampler.

• 한국문헌정보학회지
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• 제49권3호
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• pp.311-332
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• 2015

이 연구는 자기결정성 동기이론을 적용하여 독서동기를 측정할 수 있는 도구를 제안하는데 목적이 있다. 자기결정성 이론은 단순히 내적 동기와 외적 동기로 양분하지 않고, 개개인의 자율성 혹은 결정성에 따라서 무동기, 외적 조절, 주입된 조절, 동일시 조절, 통합된 조절, 내재적 동기 등 6가지로 구분하였다. 자기결정성 동기이론은 동기 유형을 세분화하여 다양한 외재적 동기를 어떻게 내면화할 것인가에 중점을 둔다. 이에 본 연구에서는 MRQ, MRP, ERAS, RSCS와 같은 기존의 독서동기 관련 측정도구를 분석하고, 이를 자기결정성원리에 의한 6개 범주로 재분류한 후, 이를 바탕으로 자기결정성이론에 의한 독서동기 측정도구를 개발하였다. 본 연구에서 제안하고자 하는 독서동기 측정도구는 자기결정성의 원리에 의거 6개 영역 30문항으로 구성되어 있다.