• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.632-638
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• 1997

To develop the Instant Nuroong-gi in a short reconstitution time, we made puffed Instant Nuroong-gi samples and investigated their physicochemical characteristics. The Nuroong-gi was prepared using a Japonica variety with three different cooking conditions: steam cooker(process A), pressure cooker (process B) and cabinet cooker(process C). The Instant Nuroong-gi is produced by adding water to the Nuroong-gi which is broken into the size of 0.5~1.0cm. The amount of the added water is 40% of the weight of the broken Nuroong-gi. And it was puffed at 160~17$0^{\circ}C$ for 30 secands. The water binding capacity of Instant Nuroong-gi samples was 7.2 at process A, 6.5 at process B and 6.6 at process C. The total sugar content of Instant Nuroong-gi samples in hot water reached at the highest level at 3-minute cooking time. Through the sensory evaluation by a panelists, we discovered that Instant Nuroong-gi prepared by a steam cooker showed the highest roasted nutty taste, hardness, stickiness and overall acceptability. And Instant Nuroong-gi prepared by a pressure cooker showed the highest color, clearness, and roasted nutty flavor. Correlation coefficients between overall acceptability and other sensory attributes of Instant Nuroong-gi indicated that hardness had the most significant correlation to sensory evaluations. When we compared the results of color test with those of sensory evaluation of Instant Nuroong-gi prepared by three different cookers, we discovered that panelists preferred yellow Instant Nuroong-gi prepared by a pressure cooker. We found some morphological properties of Instant Nuroong-gi as a result of the comparison of the crystalization by a X-ray diffraction analysis and the observation of the shapes by a the scanning electron micrographs.

• Food Engineering Progress
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• v.21 no.4
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• pp.367-374
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• 2017

The aim of this study was to evaluate the quality characteristics, antioxidant activities, and sensory properties of macaron with cabbage powder (CP). Physicochemical and sensory properties of macaron with different amounts (0%, 1%, 3%, 5%, and 7%) of CP were examined. The quality of macarons was evaluated based on spread factor, baking loss rate, color, texture, antioxidant activities, and sensory evaluation. As amount of CP addition increased, spread factor, baking loss rate, and L and a values decreased, whereas b value increased (p<0.05). For texture properties, hardness, cohesiveness, and springiness were increased by addition of CP (p<0.05). The gumminess and brittleness did not show significant changes up to 3% CP addition although significant changes in 5-7% CP addition (p<0.05) were evident. The total polyphenolic contents, DPPH radical scavenging activities, and reducing power were significantly increased by addition of CP at high concentrations (p<0.05). In the consumer acceptance of macarons, 3% CP showed the highest in color, flavor, texture, and overall acceptance and 5% CP showed the highest in taste. Meanwhile, macaron containing 7% CP showed the lowest scores in texture and overall acceptance (p<0.05). These data suggested that adding 3% of CP was the optimal concentration for making macaron.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.553-560
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• 2021

Theanine, the major amino acid and a sweet umami component of green tea, has anti-stress effects in humans. From green tea, theanine was extracted at 80℃ for 2 h using a low temperature, high pressure extractor, and caffeine was removed using an HP-20 column with 80% ethanol. Theanine extracts were applied to produce functional jelly using three kinds of gelling agents (I, II, and III) or various concentrations of theanine extracts (10-50%). Theanine jelly was characterized with respect to its physical properties, product stability, and physiological function. Gelling agent III (tamarind gum, xanthan gum, and locust bean gum=2:3:5, w/w/w) and S3 (35% theanine extracts) jelly exhibited the optimum textural properties with lower hardness and high springiness. Among theanine jellies, S3 exhibited optimum product stability, high 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, and acetylcholinesterase inhibitory activity. These results indicate that the anine extracts could be used as a neuroprotective source in the food industry.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.434-443
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• 2023

We have investigated the performance improvement of grease by synthesizing calcium sulfonate grease as an alternative to lithium grease, which is widely used globally. Since the composition ratio of the grease, when manufactured, is usually 50% base oil and 50% thickener, using grease as a lubricant in a cryogenic environment is not encouraged due to its inferior low-temperature performance. In this study, we have synthesized three types of calcium sulfonate grease with paraffin oil and PAO-based base oil and thickener. Furthermore, lithium grease was synthesized via saponification with PAO-based base oil, lithium hydroxide, 12-hydroxystearic acid, and sebacic acid. We have measured low-temperature characteristics using a rheometer and low-temperature torque meter, and tribology characteristics were obtained using a four-ball lubricant tester and schwingung reibung verschleiß (SRV). As a result, the flow point of the calcium sulfonate grease synthesized with a PAO-based base oil and thickener was found to be -40℃, overcoming the existing calcium sulfonate grease's low-temperature limitation. Moreover, the synthesized calcium sulfonate grease showed low-temperature performance similar to that of lithium grease synthesized with PAO base oil, but superior anti-wear, extreme pressure, coefficient of friction, heat resistance, adhesion, and corrosion resistance. It is thus expected to commercially replace the existing lithium grease.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.8-16
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• 2022

Rice (brown rice: milled rice=50:50) was cooked using different concentrations of hyaluronic acid (HA) solution (0.1, 0.3, 0.5, and 0.7%, respectively) as the cooking water, and the properties of the cooked rice were compared. As the HA content increased, the moisture content of the cooked rice significantly increased, and the textural properties, including hardness, cohesiveness, and adhesiveness, except springiness, significantly decreased. For color, as the HA amount increased, the L^* value decreased, whereas the b^* values increased. The free radical scavenging effect and total polyphenol content also increased significantly as the amount of HA increased. In the sensory test, the hardness of the samples containing HA was higher than that of the control; however, there was no significant difference in the overall acceptability. Based on the above results, much softer cooked brown rice could be produced using HA solution (up to 0.7%) as the cooking water, and additional beneficial characteristics, such as antioxidant effect, can be obtained.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.228.1-228.1
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• 2014

투명전도성 산화물(TCO,Transparent Conductive Oxide) 물질로 널리 사용되는 ITO 박막은 산화물 반도체를 평판 디스플레이용 투명전극 재료로 개발하기 위한 많은 연구가 진행되고 있다. ITO (Indium tin oxide)는 약 3.5 eV 정도의 넓은 밴드갭을 가진 축퇴반도체로서 전기적 및 광학적 특성이 우수하기 때문에 대표적 투명전도성 박막으로 가장 많이 사용되고 있다.현재 양산화된 ITO의 조성비는 90:10WT%인 타겟을 사용하는대 투명전극은 비저항이 $1{\times}10-3{\Omega}/sq$이하로 면저항이 $103{\Omega}/sq$전기전도성이 우수하고 380에서 780 nm의 가시광선 영역에서의 투과율이 80% 이상이라는 두 가지 성질을 만족시키는 박막이다. 본 실험에서는 SnO2 1~5wt% 인 ITO타겟을 제작하고 RF-Magnetron Sputtering을 사용하여 영구자석을 이용한 고밀도 플라즈마로 높은 점착성과, 균일한 박막 및 대면적 공정이 가능한 RF-magnetron sputtering방법으로 기판인 Slide glass위에 ITO를 증착하여 광학적 특성 및 전기적 특성에 대하여 측정하였다. 전기적, 광학적 특성 등 XRD을 통해 분석하였다. 그리고 증착된 모든 ITO 박막에서 가시광 투과율을 측정하기 위해 UV-Vis spectrophptometer을 이용하여 분석한 결과 90%이상의 높은 투과율이 측정되었다. ITO박막은 Anti-Fogging, Self-Cleaning, Solar cell 및 디스플레이소자 등 다양한 산업에 이용 가능할 것으로 생각된다.

• Tunnel and Underground Space
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• v.19 no.2
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• pp.86-94
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• 2009

A three dimensional rock joint element was developed considering fracture mechanics and subcritical crack growth to simulate non-linear behavior and the progressive failure of rock joints. Using this 3-D joint element, joint shear tests of rock discontinuities were simulated by a numerical method. The asperities on the joint surface began to fail at stress levels lower than the rock fracture toughness and continued progressively due to subcritical crack growth. As a result of progressive failing in each and every asperity, the joint showed non-linear stress-time behavior including stress hardening/softening and the reaching of a residual stress.

• Tunnel and Underground Space
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• v.12 no.2
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• pp.83-91
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• 2002

Stability analysis of rocky embankment slopes is done by both the limit equilibrium method and the finite difference method. The height or the rocky embankment is approximately 40 m and the side slope is 1 vertical to 1.5 horizontal. The cohesion and internal friction angle of rock debris are assumed zero and 43$^{\circ}$, respectively. For finite difference analysis, strength reduction method is used to calculate the saft factor of the slope. As a result, the safety factor of the slope is discovered to be 1.4 by using either methods. Considering that the design criteria of the safety factor is 1.3, it can be judged that the rock fragments embankment slope is in a stable state.

• Journal of Korean Tunnelling and Underground Space Association
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• v.12 no.5
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• pp.379-387
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• 2010

In this study, a case study was introduced for the design of a twin tunnel along high speed national highway Route 12 from Damyang to Sungsan. It was related to determine the optimal tunnel support pattern and excavation method based on a risk analysis in order to incorporate the uncertainty of ground properties. To this end, three alternatives with different amounts of support and excavation method were selected and risk analysis was performed by applying Monte Carlo simulation technique, respectively. Stability of the tunnel was quantified by the factor of safety. To improve the result, the 729 cases of the combination of ground properties (deformation modulus, cohesion, and internal friction angle) satisfying a Gaussian distribution were generated and applied. Also, stability of the tunnel was confirmed by analyzing the distribution of both displacement and shotcrete bending stress.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.11a
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• pp.226-229
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• 2001

현재 초소형 정밀기계(MEMS;Microelectromechanical System) 소자의 가장 큰 문제점으로 대두되고 있는 점착현상을 방지하기 위하여 불화유기박막을 증착하였다. Octafluorocyclobutane(C$_4$F$_{8}$)을 소스가스를 PECVD (Plasma Enhanced CVD)와 ICP (Inductively Coupled Plasma)를 이용하여 증착하였다. 여기에 Ar을 첨가하여 플라즈마의 반응성을 높여주었다. 형성된 불화유기박막의 나노트라이볼러지 특성을 살펴보기 위하여 AFM을 통하여 증착시킨 시편의 topography를 살펴보았다. 그리고 박막의 antiadhesion의 정도를 살펴보기 위하여 cantilever와 박막의 표면 사이에 존재하는 interaction force를 측정 하였고 AFM의 force curve mode를 이용하였다 PECVB를 이용하여 증착된 박막은 ICP를 이용한 박막보다 균일하지 못한 박막을 보였으며 attractive force가 강한 것으로 사료된다.