• International Journal of Advanced Culture Technology
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• 제3권2호
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• pp.100-109
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• 2015

Environmental problems from petroleum-based plastic wastes have been rapidly increasing in recent years. The alternative solution is focus on the development of environmental friendly plastic derived from renewable resource. Poly(lactic acid) (PLA) is a biodegradable polymer synthesized from biomass having potential to replace the petroleum-based non-degradable polymers utilizations. PLA can be synthesized by two methods: (1) ring-opening of lactide intermediate and (2) direct polycondensation of lactic acid processes. The latter process has advantages on high yields and high purity of polymer products, materials handling and ease of process treatments. The polymerization process of PLA synthesis has been widely studied in a laboratory scale. However, the mass scale production using direct polycondensation of lactic acid has not been reported. We have investigated the kinetics and scale-up process of direct polycondensation method to produce PLA in a pilot scale. The order of reaction is 2 and activation energy of lactic acid to lactic acid oligomers is 61.58 kJ/mol. The pre-polymer was further polymerized in a solid state polymerization (SSP) process. The synthesized PLA from both the laboratory and pilot scales show the comparable properties such as melting temperature and molecular weight. The appearance of synthesized PLA is yellow-white solid powder.

• 디지털융복합연구
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• 제18권8호
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• pp.479-484
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• 2020

외모의 중요성이 날로 증가하는 사회적 분위기 속에서 현대인의 아름다움에 대한 노력과 욕구는 더욱 활성화하고 다양해지고 있으며 이러한 영향으로 인해 뷰티미용 산업은 점점 세분화, 전문화되는 추세이다. 현대인의 과도한 퍼머넌트 웨이브나 헤어 컬러링으로 말미암아 모발 손상은 불가피한 현실인데 모발이 손상될수록 모표피가 벗겨져서 탈락하면서 인장력도 감소하여 헤어스타일링이나 펌 이후 만족도도 상대적으로 감소한다. 따라서 손상 모발에 대한 관리는 필요하지만 시중에 유통 중인 헤어 트리트먼트제는 인공합성 제품이 대부분을 차지하고 있어 인체에 유용한 항산화 물질을 함유한 헤어 트리트먼트 제품 개발이 필요하다. 본 연구에서는 단풍잎 추출물을 컬러링 한 모발의 역학적 변화에 미치는 영향을 분석하여 단풍잎의 손상 모발 회복과 모발 건강 개선을 위한 헤어 트리트먼트제 원료로서의 가능성을 연구하였다. 본 연구는 향후 천연물을 활용한 모발 미용제품 개발을 위한 기초 자료로 활용되리라 사료한다.

• 동아시아식생활학회지
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• 제14권5호
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• pp.449-456
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• 2004

Different types of coagulant and characteristics of its concentration added in the process of making milk curd were compared in this study. The pH of whey decreased when the amount of coagulant increased. The turbidity of whey was decreased when 5% of acetic acid and lemon juice were put into as coagulants. The texture of milk curd made with cow's milk and skim milk was measured the highest when acetic acid and lemon juice were added at 3, 5% of their concentration. The fracturability of milk curd made only with cow's milk decreased as the concentration of each coagulant increased. The cohesiveness was decreased as concentration of coagulant increased. The springiness was slightly changed depending on its coagulant but didn't show much of difference. The gummminess of milk curd made with cow's milk was increased when 3, 5% of coagulant was added. The result of sensory evaluation of milk curd showed that preference of milk curd wasn't depending on types of milk nor its coagulant. Also, flavor preference showed better when lemon juice was added. Preference in texture of milk curd was the highest made with cow's milk and skim milk. Preference in taste was high when 10% of lemon juice was added to skim milk and preference in its appearance showed higher when the alum was added as a coagulant to both cow's milk and skim milk than other coagulants.

• 동아시아식생활학회지
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• 제22권6호
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• pp.836-850
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• 2012

This study was conducted to identify the sensory characteristics of the Korean traditional confectionery, dasik, prepared under different conditions and to compare their consumer acceptance in Korea. To accomplish this, descriptive analysis of eight samples prepared using two types of rice cake powder, dasik (Rflour, Rflour_Omija), brown rice powder red ginseng dasik (Brice_Ginseng_P), pinepollen dasik (PineP), black sesame dasik (BSesame), bean dasik (Rbean), and two types of mungbean starch dasik (Starch_Omija, Starch_Greentea), was conducted by ten trained panelists. In addition, 81 consumers evaluated the overall acceptance (OL), acceptance of appearance (APPL), odor (ODL), flavor (FLL), and texture (TXTL) of the samples using a 9-point hedonic scale, as well as the perceived intensities of sesame flavor, sweetness, and hardness using a 9-point just-about-right (JAR) scale. Partial least square- regression (PLSR) indicated that the BSesame and Rbean samples, which had significantly (p<0.05) high roasted sesame, burnt, greasy, glossy, and cooked chestnut flavor scores, had the highest acceptability and consumer desire scores. Additionally, the PineP and Rflour_Omija samples, which had relatively high particle size, transparency, roughness, spoiled tofu, fermentation and raw rice flavor scores, were the least preferred samples. Therefore, roasted sesame, burnt, greasy, glossy, and cooked chestnut flavor attributes were considered drivers of "liking" whereas particle size, transparent, roughness, spoiled tofu, fermentation, and raw rice flavor attributes acted as drivers of "disliking" among consumers.

• 동아시아식생활학회지
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• 제24권5호
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• pp.529-543
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• 2014

The objectives of this study were to perform a descriptive analysis to characterize and compare the sensory properties of commercial Makgeolli products as well as a cross-cultural comparison of the sensory descriptions of these products between two sensory panels (Korean and Japanese). The samples used in this study were seven different types of Makgeolli, which were commercial products. A total of 10 Korean and 7 Japanese panelists were selected in Korea. Each group was trained, and they identified product attributes and performed descriptive analyses independently. The Korean and Japanese panelists generated 34 and 28 sensory attributes, respectively, to describe appearance, odor/aroma, taste/flavor, texture, and after flavor of the products. There were significant differences among the samples for 24 attributes by Korean and 23 attributes by Japanese panelists. Although there was not a large difference in the number of descriptors between Korean and Japanese panels, the Korean panelists generated more various attributes associated with flavor than the Japanese panelists, and the attributes of Japanese panelists included references to non-food products such as rotten grass. Multiple factor analysis (MFA) was applied to the descriptive analysis data from the Korean and Japanese panels to delineate the associations between Makgeolli samples and their sensory characteristics. Both the Korean and Japanese panels clustered the JRM, JSM, KRM and KSM samples into one group and the CRM and BSM samples into another group. The ESM sample was distinguished from the other six samples. These results of the cross-cultural comparison suggest that comparative analyses of sensory profiles between cultures should be conducted regularly in future studies, and further research such as consumer acceptance tests should be conducted to determine the sensory characteristics that drive consumer acceptance of Makgeolli products in the context of increasing food product exports to other countries.

• 대한화학회지
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• 제37권1호
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• pp.83-91
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• 1993

염기성 용액에서 가벼운 란탄족 원소 착물의 전기화학적 거동을 직류(DC), 펄스차이 폴라로그래피(DPP), 순환전압전류법(CV) 및 정전위 전기분해법으로 조사하였다. 란탄이온들은 NaCl 지지전해질에서 o-cresolphthalexon(OCP)과 1:1로 배위하였으며, 전극반응은 2단계 1전자 환원반응이었다. 착물의 반파전위는 pH에 따라 변화하였으며 환원전류는 흡착성을 나타냈다. DC 및 CV에서 첫번째 1전자 환원반응은 유사가역적 거동을 나타냈으며, 환원 뒤에 형성된 음이온 라디칼은 이합체와 반응을 하였다. 두번째 환원파는 전자전이 반응에 이어 생성된 카르보 음이온의 빠른 양성자 첨가반응으로 비가역적 거동을 나타냈다. -1.80V에서 정전위 전해시간이 증가함에 따라 착물의 질은 청색은 점점 옅어져서 무색이 되었으며, 최종생성물은 전기적으로 비활성이었다. 따라서 Ln-OCP 착물의 단계적인 전극반응은 ECEC 메카니즘으로 제안되었다.

• 한국식품조리과학회지
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• 제27권5호
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• pp.507-522
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• 2011

In this study, samples of wheat flour and dough were prepared by adding of 1, 3, or 5% branched dextrin, which is produced from the amylopectin of waxy corn starch using a cyclization reaction with a branching enzyme. The samples were then evaluated qualitatively in terms of farinogram, viscogram, and extensogram characteristics. The fermentation power of dough expansion, extensogram characteristics, specific volume, baking loss, external/internal surface appearance, and sensory qualities were also examined after 4 weeks of storage at -20$^{\circ}C$ to determine the effect on freeze-thaw stability and quality improvement of branched dextrins in the soft roll bread formulation. Furthermore, the samples along with a control were compared regarding their quality characteristics, including changes in moisture content, water activity, color, and textural characteristics during a storage period of 4 days at 20$^{\circ}C$ to determine the effect on preventing retrogradation of the branched dextrin. As the branched dextrin content increased, area and extensibility increased, whereas water absorption, fermentation power of dough expansion, resistance/extensibility ratio, baking loss, and brownness of the crust decreased. However, the control group presented significantly higher peak viscosity, resistance, specific volume, taste, overall acceptability, moisture content, water activity, springiness, cohesiveness, and resilience values than those of the branched dextrin samples, whereas lightness, hardness, and chewiness showed the reverse effect. As the storage period increased, lightness, hardness, and chewiness increased, whereas cohesiveness decreased. In conclusion, the results indicate that adding 1~3% branched dextrin into a soft roll bread formulation from frozen dough had no positive effect on freeze-thaw stability or preventing retrogradation but may provide good nutritional properties.

• 한국식품영양과학회지
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• 제43권8호
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• pp.1264-1269
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• 2014

쌀로부터 전분을 분리한 다음 초산화와 하이드록시프로필화한 변성 쌀 전분으로 제조하였으며 이들 쌀 전분을 밀가루에 부분적으로(10~30%) 대체하여 제조한 즉석 유탕면의 품질특성을 조사하였다. 밀가루(중력분)에 쌀 전분을 20% 대체한 복합분의 RVA 호화양상을 측정한 결과, 쌀 전분의 첨가에 의해 밀가루의 호화개시온도가 낮아져 호화속도를 빠르게 하는 효과가 있는 것으로 확인되었다. 유탕면의 조리 후 중량, 부피, 함수율은 대조구(100% 밀가루)에 비해 쌀 전분을 첨가한 면에서 높았으며 초산 쌀 전분과 하이드록시 프로필화 쌀 전분을 첨가한 면에서 보다 높게 나타났다. 천연 쌀 전분을 첨가한 유탕면은 대조구에 비해 경도, 검성, 씹힘성이 낮았으며 초산 또는 하이드록시프로필화 변성 쌀 전분의 첨가에 의해 유탕면은 검성, 응집성, 경도, 씹힘성이 더 낮게 나타났다. 쌀 전분을 첨가한 유탕면은 밀가루로만 만든 유탕면에 비해 관능점수가 다소 높게 평가되었으며, 특히 초산 쌀 전분을 첨가한 유탕면은 조리가 빠르고 외관, 색, 향, 맛, 조직감에서 관능적 기호성이 가장 향상됨을 보여 주었다.

• 지능정보연구
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• 제19권4호
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• pp.11-20
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• 2013

지능형 교통 시스템을 설계하는데 있어서, 통신, 외관, 환경, 부수 기능, 안전 등이 반드시 고려되어야 한다. 또한, 자동차를 선택하는데 있어서도, 소비자는 이러한 특성들을 고려한다. 본 논문에서는, 지능화된 교통 서비스를 운영하거나 자동차 구매 의사결정을 하는데 있어서, 자동차 색깔이 자동차 안전에 있어서 매우 중요한 의미를 갖는다는 것을 밝히고자 한다. 자동차 안전과 관련이 있는 자동차 색깔에 따른 자동차 사고 확률에 대해 연구하였다. 그리고, 전진색과 후퇴색의 개념에 대해서도 연구하였다. 전진색은 실제보다 가깝게 보이기 때문에 사고를 적게 유발하지만, 후퇴색은 실제보다 멀리 보이기 때문에 사고를 많이 유발한다. 우리는 자동차 사고 건수를 고려하여, 자동차 색깔을 8개로 분류하고 이들의 등급을 부여하였다. 또한, 우리의 연구를 실증하기 위해서, 군산에 있는 거주자를 대상으로 전화상담을 통해 조사를 하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제33권6호
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• pp.835-842
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• 2009

The present thesis carried out a research on a compression pressure's reduction phenomenon and its countermeasure according to the thermal efficiency improvement method by a Miller method in 4-cycle low speed diesel engine. In case of retardation of intake valve closing time in a engine, the theoretical heat efficiency shows a remarkably reducing trend when a compression ratio is not compensated. Accordingly, the thermal efficiency showed an increasing trend in case of compensating the compression ratio. Especially, it could be understood that the theoretical heat efficiency at near ABDC $100^{\circ}$ of intake valve closing time in case of compensation of the compression ratio was improved by around 25.1%, and the mean effective pressure was also increased by around 18.6%. Also, as the retardation of intake valve closing time increases, air quantity becomes insufficient due to a backflow phenomenon of intake air and thus thermal efficiency was decreased in a high load operation domain. The solving method of this problem is possible by supercharge. Therefore, in order to improve thermal efficiency by retardation of ntake valve closing time, the thermal efficiency improvement according to low compression is possible when there are a compensation device of a compression ratio and a supercharge device. This is a problem-solving method of low compression and high expansion cycle.