• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.362-366
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• 1999

Membranes for biosensor were prepared from poly(vinyl chloride) (PVC)l derivatives using the solution casting method, and their gas permeabilities were studied. The polymer membranes dried slowly in air showed higher permeability coefficients than those dried in vacuum. The permeabilily coefficients of carboxylated poly(vinyl chloride) (CPVC) membranes for $O_2$ and $CO_2$ decreased as the pressure of the feed gas increased. The addition of dioctylphthalate (DOP) enhanced the permeation rates for $O_2$ and $CO_2$. For example, the permeability coefficients of CPVC membranes containing 30 wt. % DOP for $O_2$ and $CO_2$ at 100 psig were 2.03 and 0.96 Barrer, respectively, which were about 4~5 times higher than those of the membranes without DOP. Poly(vinyl chloride-co-vinyl acetate-co-vinyl alcohol) (Syn-PVCAcAl) obtained by hydrolysis of poly(vinyl chloride-co-vinyl acetate (PVCA) showed a higher permeability coefficient for $CO_2$ in the presence of DOP than that for commercial PVCAcAl, but did not show any significant difference in permeability for $O_2$.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1162-1168
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• 2003

Development of chocolate products to improve the quality and functional properties with Bifidobacterium-fermented isoflavone powder (BFIP) was attempted. Effects of BFIP on sensory value, isoflavone contents, and microbiological characteristics of chocolate products during storage at room temperature $(24{\pm}0.5^{\circ})$ for 90 day were studied. Five different BFIP concentrations of 0, 1, 2, 3, and 4% (w/w) were added and blended into the chocolate products. Results of sensory evaluation showed that the scores for softness and bitter taste decreased as the BFIP contents increased. In sweet and sour taste, the highest score was shown at 1% BFIP treatment. In overall acceptability, 1% treatment was the most favored, followed by 2% treatment. Contents of isoflavone in chocolate products were stably maintained during 90 storage days. The viable cell numbers of Bifidobacterium remained relatively stable until 70 day, followed by a slow decrease thereafter in all treatments.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.145-153
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• 2009

The acute oral and genetic toxicity of ASCO EAQ80 was established in this study. ASCO EAQ80, a novel cationic surfactant produced by Aekyung Speciality Chemicals Co. LTD. is currently commercialized as a clear fabric softener. In acute oral toxicity study, the 50% lethal dose $(LD_{50})$ of ASCO EAQ80 was determined to be higher than 5000 mg/kg and this product could be classified as Category 5 or Unclassified by Globally Harmonized Classification System. Also, to establish the gene-toxicity of ASCO EAQ80, we performed bacterial reversion assay against Salmonella typhimurium TA98, TA100, TA1535, TA1537, Escherichia coli WP2uvrA, and in vitro chromosomal aberration assay against Chinese hamster lung cells in the presence and absence of S-9 metabolic activation system. From these experiments, ASCO EAQ80 revealed nonmutagenic potential in S. typhimurium TA98, TA100, TA1535, TA1537, and Escherichia coli WP2uvrA both in the absence and presence of metabolic activation system. No clastogenicity of ASCO EAQ80 was observed in chromosomal aberration assay in vitro.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.28-28
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• 2011

우리나라의 주력산업인 반도체 및 디스플레이의 경우 그 생산 설비의 1/3이상이 진공 장비이며 진공 공정을 통해 만들어진다. 이들 산업 분야에서는 우리나라가 세계 최고의 생산 기술을 가지고 있으므로 자체적인 기술 개발 확보가 중요하다. 최근에는 기존에 개발되어 있는 장비의 성능을 뛰어넘어야 하는 공정 기술력이 요구되면서, 진공 공정 기술 개발이 매우 중요한 이슈가 되었다. 반도체나 디스플레이 산업 등 기존 주력산업의 전후방 산업의 경쟁력 강화 측면에서뿐 아니라 태양전지, LED 등 진공기술을 이용한 신성장 동력 산업의 생산 시스템 경쟁력 확보 측면에서도 진공 공정 기술 개발 중요성은 매우 크다. 지금까지 양산에 적용되는 증착, 식각, 확산 등 진공 공정 운영은, 사전 시험을 통해 얻은 최적 공정의 입력 파라미터들을 정해 놓고 그대로 공정을 진행한 뒤, 생산되어 나오는 제품의 상태를 사후 측정하여 공정 이상 여부를 점검하고 미세 조정하는 형태로 진행되고 있다. 실질적으로 현재 진행 중인 진공 공정에 대한 직접적인 정보가 없으므로 공정 중 발생되는 문제들에 대한 대처는 그 공정이 끝난 후에 이루어지는 상황이다. 공정 미세화 및 대구경화에 따라 기존의 wafer to wafer 제어 개념 보다 발전된 개념으로 센서 기반 실시간 공정 진단 제어 기술의 필요성이 대두되었으며 이를 위한 오류 인식 및 예지기술 (Fault Detection & Classification, FDC) 그리고 이 정보를 이용한 첨단 제어 기술(Advanced Process Control, APC)을 개발하는 노력들이 시작되었다. 한국표준과학연구원에서는 수요기업인 대기업과 장비업체, 센서 개발 중소기업 및 학교 연구소와 공동으로 진공 공정 실시간 측정 진단 제어와 관련된 연구를 하고 있다. 진공 공정 환경측정 기술, 플라즈마 상태 측정 기술, 진공 공정 중 발생하는 오염입자 측정 원천 기술 개발과 이를 구현하기 위한 센서 개발, 화학 증착 소스 및 진공 공정 부품용 소재에 대한 평가 플랫폼 구축, 배기 시스템 진단기술 개발 등 현재 진행되고 있는 기술 개발 내용과 동향을 소개한다. 진공 공정 실시간 측정 기술이 확보되면 차세대 반도체 제작에 필요한 정밀 공정 제어가 가능해지고, 공정 이상에 바로 대응 혹은 예방 할 수 있으며, 여유분으로 필요 이상으로 투입되던 자원(대기시간, 투입 재료, 대체용 장비)을 절감하는 등 생산성을 향상을 기대할 수 있다. 또한 진공 환경에서 이루어지는 박막 증착, 식각 공정 과정에 대한 이해가 높아지고, 공정을 개발하고 최적화하는데 유용한 정보를 제공할 수 있으므로, 기존 장비와 차별화된 경쟁력을 가진 고품위 진공 장비 및 부품 개발에 기여할 수 있을 것으로 기대하고 있다.

• Applied Microscopy
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• v.29 no.4
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• pp.405-415
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• 1999

In general, transmission electron microscopy (TEM) is usually used in the investigation of polymer microstructure. Microtoming, solution casting, staining and carbon replica method are frequently introduced to the study of the polymer morphology with TEM, however the sample preparation procedure of those techniques is very difficult, and it takes a long time. The purpose of this study is to develop a new sample preparation technique which is suitable for the investigation of the various shapes and species of polyolefin microstructure by scanning electron microscopy (SEM). By modifying the conventional chemical etching method, we developed a new chemical etching technique and sample preparation procedure that are suitable for SEM study of polymer microstructure. In this study the permanganate etching method is introduced and the optimum etching condition are determined by simply adjusting the etchant formulation, concentration and etching time. This technique has shown good reproducibility and it's morphological results agree well with other works on various types of microstructures such as spherulite characterization of isotatic polypropylene $(\alpha/\beta)$, polyethylene and poly-propylene copolymer characterization, and the study of lamellar growth pattern of unsheared or oriented materials. This technique has also been applied to the industrial fields for characterization of the polyolefin film, automobile products and the others.

• Journal of Food Hygiene and Safety
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• v.24 no.2
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• pp.162-168
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• 2009

This study was conducted the analysis of food safety incidents between January 1998 and October 2008 using media reports. Total number of food safety incident was 569 through the study period. The average of food safety incident per year and month was 51.7and 4.9, respectively. The top 10 food types involved in the lists of food safety incidents were as follows; marine products, meat and meat products, confectionaries, beverages, special nutritional food, teas, noodles, soy and bean paste sauces, and milk and milk products etc. The top 10 single foods also were as follows; ready-to eats, meat, confectionary, health support foods, steeping tea, infant formula, meat products, ginseng products, foods for body weight control etc. Of the total 569 incidents, 247 (43.4%) were related with chemical hazards involving pesticide, food additives etc, biological hazards were 126 (22.1 %), and physical hazards were 97 (17.0%) incidents. In analysis stage in the food chain at which breakdown in food safety occurred, primary production were the most common stage with 364 (64%) incidents, and incidents at the manufacture handling and distribution stages were with 151 (26.5%), and 44 (7.7%), respectively. The results of this study can be used as a better data for risk analysis or food safety strategies.

• Korean Journal of Food Science and Technology
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• v.44 no.2
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• pp.155-161
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• 2012

The goal of this study was to investigate the chemical and microbiological characteristics of kimchi products distributed in Japan (5 brands, J-products) and Korea (2 brands, K-products). When their average analyses were compared, J-products showed higher values in pH, total sugar and acetic acid contents, while K-products showed higher values in number of lactic acid bacteria, sugar alcohol and lactic acid contents including textural hardness or chewiness. In addition, the analysis showed great variation in composition levels regarding pH, total sugar and acetic acid contents of J-products, and this fact revealed that different manufacturing processes are being attempted in Japan. Interestingly, some J-products had high concentrations of acetic acid with little mannitol, as this result implies that some manufacturers in Japan produce kimchi by adding acetic acid or lactic acid to control the rate of lactic acid fermentation. The result of this study elucidates the Japanese consumer's taste preference as well as the manufacturing processes in Japanese companies.

• Applied Chemistry for Engineering
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• v.17 no.1
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• pp.82-86
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• 2006

When a domestically manufactured floater is used in a general gasoline or LPG car, or a flowmeter is floated long time in the engine oil under above $150^{\circ}C$, the floater will be swelled or its organization will be slackened because weight and volume will be changed due to the osmosis of fuel. In this study, we conducted a research on a manufacturing technique of a foam-floater with the small changse in weight and volume, oil-resistance, and thermal resistance in the high temperature engine oil. When the prepared floater TROF II-3, where Nitrile Butadiene Rubber (NBR) as basic material of the floater was superseded by Hydrogenated Nitrile Butadiene Rubber (HNBR), was floated for 100 h at the engine oil of high temperature ($150^{\circ}C$), the change rates of the weight and the volume were 2.90%, and 2.56%, respectively. These were less than the NBR (TROF I-3) case, where the change rates of the weight and the volume were 10.81% and 3.08%, respectively, Therefore, TROF II-3 was determined to be suitable as an engine-oil floater in high temperature because the change of weight and volume were small, the appearance, and the specific gravity of floater were maintained uniformly in the high temperature.

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.501-505
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• 2017

Due to the rapid urbanization and increased population, there is an increase in airtight nature of buildings which causes serious indoor air pollution. Among several indoor air pollutants, volatile organic compounds (VOCs) emitted from paint are of major concern. Therefore, there is an urge for the development of environmental friendly paint products. In this wok, a natural wall paint (NWP) was prepared by utilizing a natural clay material "sericite" as a main component. A small chamber test was carried out to identify the toxic substances release from NWP and the results were compared with two eco-friendly commercial paints. The total VOCs were detected in trace level inside the test chamber and their concentrations were below the recommended indoor air quality standards. Toluene was not detected for NWP, whereas formaldehyde was observed in trace level. The toxicity index results were compared with two commercial paints and found that NWP exhibited less harmful gas emission. Based on certification rating of building materials, NWP can be classified as the first grade of building materials. Due to the above advantages, the use of sericite as a major component in NWP will be a useful technique to maintain the indoor air quality.

• Food Science and Preservation
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• v.12 no.1
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• pp.8-16
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• 2005

To develop natural antimicrobial agents for extending the self-life of Kimchi, the effect of botanical antimicrobial agent-citrus products(BAAC) on microorganisms related to Kimchi spoilage was investigated. The inhibitory effect of BAAC on microorganisms related to Kimchi spoilage was increased according to the concentration of BAAC. Antimicrobial activities of BAAC against microoiganisms related to Kimchi spoilage were remarkably high. The effect of BAAC on the cellular membrane function of microorganisms showed the perturbation of cells in the presence of BAAC. Direct isualization of microbial cells by using both transmission md scanning electron microscope showed microbial cell membrane was destroyed by treating with BAAC. It could be confirmed that BAAC completely inhibit the growth of the test strains. The pH of BAAC-added Kimchi was a little higher than that of the control through the fermentation period. Titratable acidify, vitamin C and viable cells in BAAC-added Kimchi were changed more slowly than those in the control. Sensory evaluation did not show any significant difference between $0.01\%$ BAAC-added Kimchi and the control that showed the best palatabilities during fermentation.