• 한국축산식품학회지
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• 제39권3호
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• pp.355-370
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• 2019

The present study aimed at evaluating effects of traditional sauce type and storage time on shelf-life and flavor compounds of marinated pork cooked by Sous-Vide method. Five different traditional sauces (Meju soy sauce, Brewed soy sauce, Fish-soy sauce, Ishiru fish sauce and Anchovy fish sauce) purchased from Asian countries were used. After marination with the sauces, polyvinylchloride film bags containing the marinated pork samples were cooked using Sous-Vide method for $55^{\circ}C$ for 5 h and $60^{\circ}C$ for 30 min, and were then stored for 8 wk at $10^{\circ}C$. Results showed that the pork samples marinated with the sauces retarded the growth of total plate counts (TPC) during storage. At $8^{th}$ wk storage, TPC counts were significantly lower in all samples marinated with the sauces compared to control (p<0.05). Lipid oxidation level was significantly lower in the T2 (Meju soy sauce) and T6 (Anchovy fish sauce) compared to those of T3 (Brewed soy sauce) and T5 (Ishiru fish sauce) or control after 8 wk storage (p>0.05). Forty volatile flavor compounds were detected from the control and marinated samples at $4^{th}$ wk of storage. The pork marinated with Anchovy fish sauce presented significantly higher amounts of importantly pleasant flavor compounds such as; pyrazines and sulfurcontaining compounds than those marinated with other remaining sauces and control. It is concluded that the marination with Anchovy fish sauce partly improved the shelf-life and increased amounts of pleasant flavor compounds of Sous-Vide cooked pork products during storage in comparison to the other remaining sauces.

• 한국물환경학회지
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• 제38권2호
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• pp.72-81
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• 2022

Numerous studies have investigated the occurrence and fate of microplastics in the environment; however, only limited effort has been devoted to exploring the characteristics of dissolved organic matter (DOM) leached from microplastics. In microplastic (MP)-contaminated environment, MPs are typically mixed with naturally-occurring particles, which interferes with their detection in the environment. Thus, it is necessary to distinguish between the DOM leached from MPs and those leached from natural particles and also to characterize their properties. This study investigated DOM leaching behavior from MPs (polystyrene: PS, polyvinylchloride: PVC) and natural particulates (forest soil: FS, litter leaves: LL) under light, which is considered one of the main weathering processes that affect MPs in the environment. The leached DOM concentrations and fluorescence characteristics were compared under dark versus light conditions. Regardless of the origins, UV light promoted DOM release from all the particulates. More DOM was released from natural particles than from MPs under both conditions. However, the effect of promoting DOM release by UV was more pronounced for MPs than for natural particles. It was observed from fluorescence spectra that the intensity of the humic-like region was substantially reduced when MP-derived DOM was exposed to UV light, whereas the change of intensity was very little for natural particles. Under light conditions, the ratio of protein-like to humic-like fluorescence of MP-derived DOM was higher than that of DOM from natural particles. This study implies that a substantial amount of DOM could be leached from MPs even in MP-polluted environment under UV irradiation. Protein/humic fluorescence ratio could be utilized as a fast probing indicator to separate the two sources of particles under light.

• 한국식품영양과학회지
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• 제25권6호
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• pp.944-950
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• 1996

본 연구는 외국산 냉장쇠고기의 국내 수입에 따른 한우쇠고기의 경쟁력 제고와 저장성 증진을 위하여 한우 암소 1등급의 등심을 재료로 포장방법에 따른 냉장저장 중 이화학적 성질 변화를 조사하였다. 시료는 진공포장(포장재: polyamide/polyethylene, $50ml/\m^2.24h.$ atm)과 일반포장(포장재: polyvinylchloride, $80~320ml/\m^2.24h.atm)을$ 하였으며, 포장된 각군은 다시 형광등 조사군과 암실 보존군으로 나누었다. pH 변화는 저장 21일 동안 진공포장군의 경우 형광등 조사 여부에 관계없이 점차 감소하는 경향이었으나, 일반포장군은 점차 상승하는 경향을 보였다. VBN값은 진공포장군과 일반포장군 모두 저장기간에 따라 증가하는 경향을 나타내었으며, 진공포장군이 일반포장군에 비하여 저장 15일째 이후부터 유의하게 낮았다. TBA 값은 저장 초기에 비하여 저장 전기간 동안 진공포장군이 일반포장군에 비하여 낮게 유지되었다. 적색도에서는 진공포장군과 일반포장군 모두 저장기간에 따라 점차 감소하는 경향이었으며, 진공포장군은 일반포장군에 비하여 전저장기간 동안 높은 값을 나타내었다. 지방산 조성변화를 보면, 저장기간에 따라 포화지방산의 함량은 점차 증가하는 반면, 불포화지방산의 함량은 감소하였는데, 그 변화정도는 진공포장군이 일반포장군에 비하여 크게 낮았다. 본 연구에서 형광등 조사군과 암실 보존군간에는 이화학적 성질의 차이가 뚜렷하지 않았다.

• 대한화학회지
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• 제41권7호
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• pp.337-342
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• 1997

본 연구에서는 benzo-15-crown-5(B15C5)와 poly(acryloylmethylbenzo-15-crown-5)[poly(AMB15C5)] 화합물을 이온선택성 물질로 이용해서 $Pb^{2+}$를 전위차법으로 정량할 수 있는 탐침형 이온선택성 전극(coated wire-ion-selec-tive electrode[CWISE])을 개발하였다. 각각 감지막의 최적 조성은 B15C5의 경우에는 리간드 20 mg, 가소제인 tris(2-ethylhexyl) ester 165 mg, 지지체인 polyvinylchloride 75 mg 및 용매인 THF 0.7 mL이었으며 poly(AMB15C5) 경우에는 리간드 35 mg, 가소제인 tris(2-ethylhexyl) ester 160 mg, 지지체인 PVC [Polyvinyl Chloride] 70 mg 및 용매인 THF 2 mL이었다. 이 때 코팅용액의 리간드에 대한 무게함량은 각각 7.7%와 13.1%이었다. 각각의 전극은 $10^{-5} M{\sim}10^{-1}$ M 농도 범위에서 기울기가 28{\pm}1$ mV/decade인 직선성이 잘 성립하는 감응을 나타내었다. 또한 전극의 감응시간은 poly(AMB15C5) 경우에는 5분 이내였으며 B15C5의 경우에는 3분이내로 비교적 빠른 편이었다. 전극의 안정성은 크라운 에테르의 물에 대한 용해도 때문에 좋은 편은 아니었다. 최적 pH 조건은 pH 3~6이었으며 $Mg^{2+},\; Ca^{2+},\; Co^{2+},\; Ni^{2+},\; Cu^{2+},\; Zn^{2+}$ 및 $Cd^{2+}$는 방해가 거의 없었으나 $Na^+$와 $K^+$는 방해효과가 컸다. 그리고 본 연구에서 제조한 탐침형 이온선택성 전극을 이용하여 $Pb^{2+}$ 이온을 전위차 적정법으로 정량분석해 보았을 때 이론적인 당량점과 종말점이 잘 일키하는 결과를 얻었다.

• 한국산업보건학회지
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• 제8권1호
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• pp.50-66
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• 1998

This study was conducted to estimate crystalline silica contents in airborne respirable dust from various manufacturing industries and to compare analytical performance of two methods of quantifying crystalline silica, X-ray diffraction(XRD) and Fourie transform infrared spectroscopy (FTIR). For this study, various manufacturing industries with a history of having pneumoconiosis cases and also known to generate dusts containing crystalline silica were investigated. These industries include: foundry, brick, potteries, concrete, and abrasive material, etc. Both personal and area respirable dust samples were collected using 10 mm, Dorr-Oliver nylon cyclone equipped with 37mm, $5{\mu}m$ pore size, polyvinylchloride (PVC) filters as collection media. In addition, total dust samples were collected side-by-side to the respirable samples. All samples were weighed before and after sampling and were pretreated according to the NIOSH sampling and analytical methods 0500, 7500, and 7602 for dust collection and quartz analysis. In addition, bulk samples were collected and analyzed by X-ray fluorescence (XRF) for minerals. In this article, only the results obtained from foundry are reported. The results from various other industries will be published in future articles. The respirable dust concentrations from personal samples by cyclone were $0.46-1.06mg/m^3$ and those from area samples were $0.34-0.73mg/m^3$. Dust concentrations of personal samples were significantly higher than those of area samples. The highest dust concentration was obtained from the personal samples of the finishing operation. Total dust concentration ranged $1.24-3.40mg/m^3$. The mean quartz contents estimated by FTIR and XRD in the personal respirable dust samples were 5.12% and 4.41%, respectively, without significant difference between them. For quartz analyses, the two techniques were highly correlated with $r^2$ ranged 0.803-0.920. But the results by FTIR were mostly higher than those by XRD. In addition, cristobalite was not detected by FTIR. Significant correlations between contents of crystalline silica and such minerals as $Al_2O_3$, CaO, $TiO_2$, and $K_2O$ suggest possible interferences from these minerals.

• Composites Research
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• 제31권4호
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• pp.122-127
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• 2018

섬유강화고분자복합재료(CFRP, Carbon Fiber Reinforced Plastics)의 경량화는 자동차 및 항공 분야에서 끊임없이 요구되고 있으며, 구조용 폼과 CFRP를 혼합하여 샌드위치 복합재료로 사용되고 있다. 본 연구에서는 열경화성 소재인 에폭시 폼과 폴리우레탄 폼 및 열가소성 소재인 PET 폼과 PVC 폼의 조성 차이에 따른 폼의 형상 및 열 노화를 통해 변화되는 기계적 특성 변화를 관찰하였다. 성형한 에폭시 폼, 폴리우레탄 폼 및 상용화된 PET 폼과 PVC폼을 180도에서 열 노화시켰으며, 30, 60, 120, 180분의 노화시간에 따라 구조용 폼의 변화를 광학 현미경 및 만능시험기로 폼 셀의 형상 및 압축강도를 평가하였다. 궁극적으로 에폭시 폼이 가장 높은 2.6 MPa의 압축강도를 가졌으며, 열 노화 조건에서도 물성저하나 형상의 변화가 거의 발생되지 않았다. 이는 에폭시 폼이 타 구조용 폼에 비해 열 노화 조건에서 후경화되어 강직한 조성을 이루며, 타 구조용 폼과는 다르게 내열 특성이 우수하기 때문에 고온용 구조용 폼으로 적용하기 적합한 소재임을 확인하였다.

• 한국산업보건학회지
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• 제9권1호
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• pp.99-111
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• 1999

The purpose of this study was to evaluate crystalline silica contents in airborne respirable dusts from various manufacturing industries and to compare analytical ability of two different methods of quantifying crystalline silica, X-ray diffraction(XRD) and Fourie transform infrared spectroscopy(FTIR). Various manufacturing industries with a history of having pneumoconiosis cases and also known to generate dusts containing crystalline silica were investigated. These industries include: ceramics, brick, concrete, and abrasive material etc. The personal respirable dust samples were collected using l0mm, Dorr-Oliver nylon cyclone equipped with 37mm, $5{\mu}m$ pore size. polyvinylchloride (PVC) filters as collection media. All samples were weighed before and after sampling and were pretreated according to the NIOSH sampling and analytical methods 7500, and 7602 for dust collection and quartz analysis. A total of 48 samples were collected from these industries. Initial analyses of these samples showed log-normal distributions for dust and quartz concentrations. Some results from ceramics and stone exceeded current Korean Occupational Exposure Limits. The average concentrations of personal respirable dust by cyclone were 0.43, 0.24, 0.26, 0.42, 0.53 and $0.29mg/m^3$ in ceramics, stone, concrete, glass, briquets, and others, respectively. A comparison of performance of two analytical methods for quantifying crystalline silica was performed using data from ceramics. The results showed that no significant difference was found between two methods for ceramics. The mean crystalline silica contents determined by XRD were 3.41 % of samples from briquets and 7.18 % from ceramics and were 2.58 % from concrete and 10.33 % from ceramics by FTIR. For crystalline silica analysis, two analytical techniques were highly correlated with $r^2=0.81$ from ceramics. Both cristobalite and tridymite were not detected by XRD and FTIR.

• 한국환경생물학회:학술대회논문집
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• 한국환경생물학회 2002년도 학술대회
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• pp.141-144
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• 2002

Environmental estrogens are natural or synthetic substances present in the aquatic environment, especially in effluent from sewage treatment. However, the adverse effects of these estrogenic substances on fish reproduction are unknown. Di-2-ethylhexyl phthalate (DEHP) is the most common phthalate, which Ps used as a plasticizer in polyvinylchloride (PVC), and it is widespread in the environment and has been found in aquatic organisms and sediments. Therefore, juvenile common carps (Cyprinus carpio) were exposed to nominal concentrations of 17$\beta$-estradiol (E2) (0.5, 5, 50 $\mu\textrm{g}$/L) and DEHP (10, 100, 500 $\mu\textrm{g}$/L) for 21 days, to determine the adverse reproductive effects of these compounds on plasma vitellogenin (VTG) induction, sex steroid level, and gonad weight. Electrophoresis (SDS-PAGE) revealed that much of VTG was induced in fish exposed to 5 and 50 E$_2$ $\mu\textrm{g}$/L, but none of DEHP exposure showed induction. Enzyme-linked immunosorbent assay (ELISA) revealed that VTG was significantly induced in fish exposed to 5 and 50 E$_2$ $\mu\textrm{g}$/L, and combination of 50 E$_2$ $\mu\textrm{g}$/L with 10 and 500 DEHP $\mu\textrm{g}$/L, but none of DEHP exposure showed induction. Analysis of sex steroid levels in some fish revealed that testosterone (T) was detected in both male and female fish of the control and DEHP exposures, but none of fish exposed to 22 concentrations had detectable testosterone level. On the other hand, E$_2$ exposure induced 17$\beta$-estradiol in plasma of male fish, but there was no induction of 17$\beta$-estradiol in plasma of male fish exposed to DEHP. Comparison of gonadosomatic index (GSI) revealed that maximal E$_2$ exposure inhibited ovarian growth, but maximal DEHP exposure stimulated testicular growth. The results indicated that those comparisons can be a useful bio-indicator for determining adverse reproductive effect of endocrine disrupting chemicals (EDCs).

• 공업화학
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• 제28권1호
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• pp.42-49
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• 2017

프탈레이트계 PVC 가소제를 대체하기 위해 식물유 기반 아세틸화 모노글리세라이드(AMG)계 가소제를 합성하여 PVC에 대한 가소성능을 평가하였다. 코코넛 오일과 글리세롤로부터 전이 에스테르화 반응과 아세틸화 반응을 거쳐 AMG-CoCo를 합성하였고 글리세롤 모노올리에이트(GMO)로부터 아세틸화 반응을 통해 AMG-GMO를 그리고 추가적으로 에폭시화 반응을 거쳐 AMG-GMO-Epoxy 합성하고 그 구조들을 확인하였다. AMG계 가소제의 열안정성을 평가한 결과, AMG-CoCo < AMG-GMO < AMG-GMO-Epoxy 순으로 열분해 온도가 높았으며 모두 상용 가소제인 DOP의 열분해 온도보다 높았다. AMG계 가소제를 함유한 PVC의 경우, 인장 신율은 770~810%, 인장 강도는 약 19~22 MPa로 DOP로 가소화된 PVC보다 우수하였다. DMA 분석 결과, AMG-GMO-Epoxy와 PVC는 매우 우수한 섞임성을 보여주었고 AMG-GMO-Epoxy를 50 phr 함유한 PVC의 $T_g$는 $24^{\circ}C$까지 감소하였다. 물에 대한 가소제의 용출 실험 결과, AMG-GMO와 AMG-GMO-Epoxy를 50 phr 포함한 PVC 경우 무게 감소가 약 2%와 1%로 내용출성이 매우 우수함을 알 수 있었다. 따라서 AMG-GMO-Epoxy가 DOP를 대체할 PVC 가소제로 경쟁력이 있다고 할 수 있다.

• 공업화학
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• 제16권2호
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• pp.296-303
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• 2005

PVC와 ABC의 혼합물을 대상으로 혼합비에 따른 공열분해 특성과 CaO와 $Cu_2O$의 첨가효과를 TG와 GC-MS를 이용하여 연구하였다. $500^{\circ}C$의 등온실험에서 ABS의 혼합비율이 증가할수록 스티렌 단량체와 방향족 화합물의 수율은 증가하였으며, BTX 화합물의 최대 수율은 PVC와 ABS의 혼합비가 4:1일 때 16.14% 정도임을 확인하였다. 금속산화물을 첨가한 경우 액상 생성물의 수율은 혼합비 0.4의 CaO를 첨가했을 때 73%와 0.4의 $Cu_2O$를 첨가했을 때 70%인 최대값을 얻을 수 있었으며, 각각 혼합비 0.5인 CaO와 1.0인 $Cu_2O$를 첨가했을 때 기상 생성물에 포함된 염화수소를 완전히 제거할 수 있었다. 본 연구의 실험조건에서는 염화수소를 완전히 제거할 수 있고, 가장 높은 액상 수율을 얻을 수 있는 반응조건은 $500^{\circ}C$에서 혼합비 0.5인 CaO나 혼합비 1.0인 $Cu_2O$를 첨가하는 것으로 사료된다.