굴 패각 분말을 함유한 항균성 복합 필름의 제조 및 특성 연구

박기태,서종철,Park, Kitae,Kambiz, Sadeghi,Seo, Jongchul 한국포장학회 2021 한국포장학회지 Vol.27 No.1

In this study, ethylene vinyl acetate (EVA) and low density polyethylene (LDPE) composite films (EVA/LDPE-OSP) containing calcined oyster shell powder (OSP) were prepared using twin-screw extruder as an antimicrobial packaging material. The OSP composite was initially prepared and then incorporated into an EVA/LDPE blend at different ratios (0, 1, 3 and 5%) to develop the EVA/LDPE-OSP composite films. The as-prepared EVA/LDPE-OSP composites films were evaluated using FT-IR, DSC, TGA, OTR, WVTR, SEM and UTM as well as antimicrobial activity was examined using JIS Z 2801:2000 standard. OPS endowed the antimicrobial potency to the composite films against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. In addition, the incorporation of OSP remarkably enhanced the thermal stability. OSP as a natural biocidal agent can be used as a multifunctional additive in packaging industry such as improving the thermomechanical properties and preventing the microbial contamination of packaged products.

조미김 포장을 위한 PET/PVA-BA/OPP 다층필름 제조 및 특성분석

임미진,김도완,서종철,Lim, Mijin,Kim, Dowan,Seo, Jongchul 한국포장학회 2017 한국포장학회지 Vol.23 No.1

To identify applicability for packaging material of polyvinyl alcohol (PVA)/boric acid (BA) coating solution with highly-enhanced water vapor and oxygen barrier properties, the PET/PVA-BA/OPP multi-layer films were prepared through comma coating and lamination process. The oxygen and water vapor permeabilities, and tensile strength of as-prepared multi-layer films were investigated before and after pressure cooker test (PCT). Although oxygen and water vapor permeabilites, and mechanical properties of PET/PVA-BA/OPP multi-layer films was decreased after PCT, their properties were highly enhanced as increase of BA contents in PVA matrix. This is strongly related with enhanced cross-linking density in PVA-BA layer. In storage test of seasoned-laver, the PET/PVA-BA/OPP multi-layer films were comparatively effective to suppress the increase in peroxide value originating from oxidation of seasoned-laver. Comparing the commercially available PP/Al-metallized PP for seasoned-laver packaging, however, PET/PVA-BA/OPP multi-layer films did not show any advantage in water activity. This is due to higher water vapor permeation properties of as-prepared multi-layer films. Therefore, further studies are required to enhance the water vapor permeation in PET/PVA-BA/OPP multi-layer films.

다공성 기재를 이용한 닭가슴살 신선도 인디케이터 제조 및 특성

이가은,백승혜,김도완,서종철,Lee, Kaeun,Baek, Seunghye,Kim, Dowan,Seo, Jongchul 한국포장학회 2017 한국포장학회지 Vol.23 No.1

To visually identify the spoilage of chicken breasts, a three layered freshness indicator consisting of PET/bromocresol green (BCG)-ethylene vinyl acetate (EVA)-acetic acid (AA) composite layer/porous substrates was successfully prepared and their performance were simulated at 20% of $CO_2$ and 4 different trimethylamine (TMA) concentrations to evaluate color change at minimal spoilage level. The visibility and range of color changes of the as-prepared indicators responding to TMA concentration as a simulant were strongly dependent on the concentrations of BCG and AA. As the BCG content increased, the visibility of color change in the freshness indicators was apparently improved and the range of color change could be controlled by contents of AA. Among the as-prepared freshness indicators, 'G0.12_A0.5' which consisting 0.12g of BCG and 0.5g of AA was selected as an optimum composition due to the highest visibility at TMA 20 mg% corresponding to the minimal spoilage level. The color of the indicator changed from yellow to green for spoilage indication of chicken breast, which could be easily seen with the naked eyes and well consistent with the simulation results. It is expected that our developed freshness indicator can be useful in monitoring various food freshness and quality.

태안해안국립공원 바람아래 특별보호구역의 지형 및 염생식물 분포특성 연구

박정원(Jeongwon Park),서종철(Jongchul Seo),김진석(Jinseok Kim),오선관(Sunkwan Oh),박정원(Jungwon Park) 국립공원연구원 2013 국립공원연구지 Vol.4 No.1

본 연구는 바람아래 할미섬 특별보호구역의 자연해안 복원 연구를 위하여 현재의 해빈의 높이, 면적, 해안의 길이, 사구정상의 높이 등 정확한 지형의 현황을 분석하고 지형특성에 따른 사구·염생식물 분포를 분석하고자 하였다. 할미섬 지형의 최고높이는 17m이며 제일 낮은 높이는 평균 3m에서 5m로 섬 남단 만입에서 남동쪽 니질조간대 지역이다. 연구지역내 총 소산식물은 17목 23과 40속 49종 3변종 8외래종이 생육하고 있으며 곰솔군락, 갈참나무군락, 보리장나무군락, 아까시나무군락, 순비기나무군락 등 5개 목본군락과 띠군락, 갯그령군락, 갯잔디군락, 나문재군락, 왕잔디군락, 갯메꽃군락, 해홍나물군락, 천일사초군락, 갯쇠보리군락, 통보리사초군락 등 10개 염생·사구식물군락이 분포하고 있으며 갯그령-띠군락, 띠-갯메꽃군락, 띠-갯그령군락, 띠-은백양나무군락 등 4개의 혼합군락이 분포하고 있다. 식물의 공간적 분포 특성은 곰솔(Pt1), 갯그령(Em2,3,4), 갯잔디(Zs5)를 제외한 식생군락의 대부분이 10m2에서 500m2의 작은 패치형태를 띄고 있으며 높이는 평균 4m에서 6m 사이, 해안선으로부터 거리는 100m에서 150m 사이에 분포하고 잇는 것으로 분석되었다. This study was carried out to investigate the exact current status of the topography such as the present beach elevation and area, coastline and the height of the dune crest, with the analysis of the distribution of the sand dune·halophytes on geomorphic characteristics for the restoration of natural coast in the protection zone of Baramarye Halmi-island. Halmi-island has the maximum height of 17m and the lowest height of average 3m to 5m, which is the muddy tidal flat area located southeast of the embayment on the southern tip of the island. The total distribution of plants in the research sites are 17 orders, 23 families, 40 genus, 49 species and 8 exotic species: 5 arbors communities including Pinus thunbergii, Quercus aliena, Elaeagnus glabra, Robinia pseudo-acacia, Vitex rotundifolia etc., 10 halophytes and sand dune plants communities including Calystegia soldanella, Suaeda maritima, Carex scabrifolia, Ischaemum anthephoroides, Carex kobomugi etc and 4 mixed communities including Elymus mollis-Imperata cylindrica var. koenigii, Imperata cylindrica var. koenigii-Calystegia soldanella, Imperata cylindrica var. koenigii-Elymus mollis, Imperata cylindrica var. koenigii-Populus alba etc. The spatial distribution characteristics of plants are identified that the most plant community are distributed in the distance of between 100m to 150m from the coastline, with the small-scale patch structure of 10m2 to 500m2 and the height of average 4cm to 6cm except Pinus thunbergii (Pt1), Elymus mollis (Em2,3,4) and Zoysia sinica (Zs5).

초음속 충동형 터빈 성능개선을 위한 동익 오버랩 최적설계

조종재(Jongjae Cho),서종철(Jongchul Seo),김귀순(Kuisoon Kim) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.11

동익 오버랩은 축류 터빈의 성능향상을 위해 적용되며, 동익의 익단과 익근에 추가적인 높이를 적용함으로써 충분한 유로를 확보할 수 있다. 특히, 초음속 터빈에서는 동익 유로에서의 질식 가능성을 줄이며, 설계 압력비를 구현할 수 있도록 한다. 하지만 동익 오버랩을 적용하면, 펌핑손실, 확산손실 등의 추가적인 손실이 동반된다. 따라서 터빈 성능향상을 최대화하기 위해 최적화 기법을 적용하였으며, 최적화 과정의 효율성을 위해 근사 최적화 기법을 사용하였다. 설계변수는 동익 오버랩의 형상변수이다. 연구결과를 통해, 최적화된 동익 오버랩에 의한 상당한 터빈 성능향상을 확인할 수 있었다. A rotor overlap technique was adapted to improve the performance of a axial turbine. The technique secured sufficient flow passage by additional height at the rotor tip and hub. especially in a supersonic turbine, the technique reduced the chance of chocking in the rotor passage, and made to be satisfied the design pressure ratio. However, the technique also made additional losses, like a pumping loss, expansion loss, etc. Therefore, a optimization technique was appled to maximize the improvement of the turbine performance. An approximate optimization method was used for the investigation to secure the computational efficiency. The design variables was shape factors of a rotor overlap. Results indicated that a significant improvement in turbine performance can be achieved through the optimization of the rotor overlap.

2단형 초음속 터빈의 유동에 대한 전산해석

조종재(Jongjae Cho),서종철(Jongchul Seo),김상조(Sangjo Kim),김귀순(Kuisoon Kim),정은환(Eunhwan Jeong) 한국추진공학회 2010 한국추진공학회 학술대회논문집 Vol.2010 No.5

본 연구에서는 2단형 초음속 터빈의 유동에 대한 전산해석을 수행하고 그 결과를 비교 분석하였다. 2단 전체에 대한 계산을 상용 유동해석 프로그램인 FLUENT<SUP>TM</SUP>사용하였다. 2단 동익에 대한 계산을 통하여 2단 동익의 중첩높이의 변화에 따른 터빈의 성능변화를 고찰하였다. 또한 2단 동익에서 슈라우드의 유·무에 따른 터빈의 성능변화를 고찰하였다. Numerical Analysis of two-stage supersonic turbines were conducted, and the results were analyzed. FLUENT<SUP>TM</SUP> commercial flow analysis package was employed for the calculation of the turbine. Characteristics of the turbine performance were investigated according to the overlap height and existence of the shroud at the second rotor blade through the calculations.

90° 곡관에서의 비축대칭 끝벽과 끝벽 경계층 판을 이용한 유동특성 향상

조종재(Jongjae Cho),김상조(Sangjo Kim),서종철(Jongchul Seo),김귀순(Kuisoon Kim),정은환(Eunhwan Jeong) 한국추진공학회 2011 한국추진공학회 학술대회논문집 Vol.2011 No.5

본 논문에서는 가스터빈 유로의 공력열환경을 개선시키기 위해서 비축대칭 끝벽과 끝벽 경계층 판의 형상 최적화를 수행하였다. 터빈 유로 모사를 위해 90° 곡관을 이용하였다. 본 연구는 터빈 유로에서의 전압력 손실과 유로 끝벽에서의 열전달 계수를 최소화하기 위한 비축대칭 끝벽과 끝벽 경계층 판의 형상을 찾는 것이다. 최적화 과정의 효율성을 위해 근사 최적화 방식을 사용하였다. 최적화된 비축대칭 끝벽과 끝벽 경계층 판을 통해, 상당한 공력열환경 개선을 확인할 수 있었다. This paper presents the shape optimization of a nonaxisymmetric endwall and endwall boundary layer fence which improve the aerothermal environment of a gas turbine passage. The endwall and fence methods were used simultaneously. The turbine passage was simulated by a 90° turning duct (ReD=360,000). The main purpose of the present investigation was to focus on finding a nonaxisymmetric endwall and boundary layer fence with minimum total pressure loss in the passage and heat transfer coefficient on the endwall of the duct. An approximate optimization method was used for the investigation to secure the computational efficiency. Results indicated that a significant improvement in aerothermal environment can be achieved through the application of a nonaxisymmetric endwall and boundary layer fence.

붕산 가교 폴리비닐알코올 기반 통한 생분해성, 생체적합성, 고강도, 고차단성 종이 코팅

최신형 ( Shinhyeong Choe ),유슬기 ( Seulki You ),박기태 ( Kitae Park ),김영주 ( Youngju Kim ),박제희 ( Jehee Park ),조용준 ( Yongjun Cho ),서종철 ( Jongchul Seo ),양한슬 ( Hanseul Yang ),명재욱 ( Jaewook Myung ) 유기성자원학회 2023 학술대회 발표자료집 Vol.2023 No.2