• Journal of the Korean Ceramic Society
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• v.36 no.1
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• pp.97-105
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• 1999

In the binary system of SiC and carbon, porosity and pore size distribution of green body was controlled by varying pH, by the addition of polyelectrolyte dispersants, and by using different particle size of starting powders. The preforms having different green microstructure were fabricated by slip casting from suspensions having different dispersion condition. The reaction bonding process was carried out for these preforms. The condition of reaction bonding was 1600$^{\circ}C$ and 20 min. under vacuum atmosphere. The analyses of optical and SEM were studied to investigate the effect of green microstructure on that of reaction bonded silicon carbide and subsequently the mechanical properties of sintered body was investigated. Different green microstructures were obtained from suspensions having different dispersion condition. It was found that the pore size could be remarkably reduced for a fine SiC(0.5$\mu\textrm{m}$). The bimodal microstructure was not found in the present study, which is frequently observed in the typical reaction bonded silicon carbide. It is considered that the ratio between SiC and C was responsible for the formation of bimodal microstructure. For the preform fabricated from the well dispersed suspension, the 3-point bending strength of reaction-bonded silicon carbide was 310${\pm}$40 MPa compared to the specimen fabricated from relatively agglomerated particles having lower value 260${\pm}$MPa.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.758-763
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• 2011

In this work, polymer composite electrolytes were prepared by a blend of poly(methyl methacrylate) (PMMA) and poly(ethylene oxide) (PEO) as a polymer matrix, propylene carbonate as a plasticizer, $LiClO_4$ as a salt, and by containing a different content of $TiO_2$, by using the solution casting method. The crystallinity and ionic conductivity of the polymer electrolytes was evaluated using X-ray diffraction(XRD) and AC impedance method, respectively. The morphology of composite electrolyte film was analyzed by SEM method. From the experimental results, by increasing the $TiO_2$ content, crystallinity of PEO was reduced, and ionic conductivity was increased. In particular, the ionic conductivity was dependent on the content of $TiO_2$ and showed the highest value 15 wt%. However, when $TiO_2$ content exceeds 15 wt%, the ionic conductivity was decreased. According to the surface morphology, the ionic conductivity was decreased because the polymer composite electrolytes showed a heterogenous morphology of fillers due to immiscibility or aggregation of the filler within the polymer matrix.

• Journal of Mushroom
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• v.11 no.3
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• pp.149-153
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• 2013

The oyster mushroom is a wide cultivar among cultivated edible mushrooms in Korea. But, due to the excess of domestic production, the price has been falling. This study has been conducted to develope new variety oyster mushroom(Pleurotus ostreatus) which have a long term storage to export in foreign market as well as domestic. 'Gonji-7ho', a new variety of oyster mushroom, for the bottle culture, was bred by mating with monokaryons isolated from 'Nongmin-59ho' and 'MT07156'. In the characteristics of fruit body, pilei were round type and gray and stipes were white color and soft. The fruit body growth was vital and uniform. When fruit-body was stored at 4 degrees after packing with plastic vinyl, storage period was extended 7 days longer than 28 day of chunchu-2ho. The yield was 166 g per a bottle(￠65, 900 ml).

• Journal of the East Asian Society of Dietary Life
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• v.18 no.3
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• pp.353-360
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• 2008

This study evaluated the quality characteristics of dried noodles made of wheat flour supplemented with different concentrations of skate powder. Cooking quality, mechanical texture properties, gelatinization temperature and viscosity were measured, after which sensory evaluation was performed with prepared noodles. Water binding capacity, solubility and swelling power of the composite skate powder and wheat flours were higher than those of pure wheat flour. Gelatinization temperature of the composite skate powder and wheat flours increased, while initial, interim, and maximum-viscosity at $95^{\circ}C$, decreased, with increasing skate powder content. In relation to color values, increasing skate flour content led to decrease in L and b values and increase in a value. For the textural characteristics, the addition of skate powder increased hardness, springiness, chewiness and adhesiveness. Overall, noodles made with 3% skate powder were preferred compared to other samples.

• Journal of Periodontal and Implant Science
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• v.35 no.3
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• pp.549-561
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• 2005

이 연구의 목적은 새로이 제작된 chitosan-poly(L-lactic acid)(PLLA) 다층 다공성 차폐막의 생체적합성 및 골세포활성도 및 골재생능을 평가하는 것이다. 제작된 차폐막을 24 well에 넣고 clonal osteoblast-like cell line(MC3T3-E1)을 접종한 군을 실험군으로, 차폐막을 사용하지 않은 대조군으로 하였다. 배양 1일, 7일 및 14일째에 각 well에서 세포수를 측정하였다. 주사전자현미경을 이용하여 차폐막에 부착된 세포의 형태관찰을 시행하였다. RNA 추출 및 RT-PCR을 실시한 후, agarose gel상에서 전기영동하여 조골세포 표식자인 collagen type I(COL), osteopontin(OP) 및 osteocalcin(OC) mRNA의 발현을 관찰하였다. 제작된 매트릭스의 생체적합성 및 골재생능을 관찰하기 위하여 백서의 두개골에 직경 8mm의 원형 결손부를 형성한 후 차폐막을 이식한 군을 실험군으로, 아무 것도 넣지 않은 군을 대조군으로 하여 4주 경과 후 실험동물을 희생시킨 후 조직학적관찰을 시행하였다. 시간경과에 따른 부착세포수 관찰결과, 배양 14일까지 조골세포의 수가 지속적으로 증가하였고, 주사전자현미경으로 세포의 형태 관찰결과, 배양된 세포들은 중층의 형태로 성장하면서 시간경과에 따라 세포가 응집되는 양상을 나타내었다. 관찰 기간동안 COL, OP, 및 OC mRNA의 발현이 관찰되어 배양 전 기간동안 조골세포의 형질이 잘 유지되고 있음을 알 수 있었다. 백서 두개골 결손부에 이식된 차폐막은 염증반응 없이 주위 조직과 우수한 생체적합성을 나타내었으며, 차폐막을 이식하지 하지 않은 대조군에 비해 높은 신생골 형성을 나타내었다. 이상의 관찰결과로 새로이 제작된 chitosan-PLLA 차폐막은 우수한 생체적합성 및 골재생능을 나타냄을 알 수 있었으며, 향후 이를 골조직 재생 및 치주조직유도재생 분야에 응용될 수 있을 것으로 생각된다.

• Culinary science and hospitality research
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• v.21 no.5
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• pp.88-97
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• 2015

This study was conducted to evaluate the effect of Citrus peel powder on the quality characteristics of sponge cake. Citrus peel powder sponge cake was prepared with different ration of Citrus peel powder(0, 10, 20, 30, 40%). The specific gravity, baking loss rate and cake weight increases as the ratio of Citrus peel powder. The sponge cake's a, b level increased with the increasing level of Citrus peel powder 40% appeared to be the highest. In terms of textural characteristics, the samples containing 10, 20, and 40% Citrus peel powder had significantly higher hardness than the control samples. The substance's level of springiness, and cohesiveness decreased as the Citrus peel powder additive increased. In sensory evaluation, overall acceptability and taste of the cake was better than others when 10% Citrus peel powder was added. The results indicated that substituting 10% Citrus peel powder to sponge cake is optimal for quality and provides a product with reasonable high overall acceptability.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.4
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• pp.293-300
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• 2016

Purpose: The purpose of this study is finding proper bonding agents to be used when adding bis-acryl composite provisional materials. Materials and Methods: Three bonding agents with different chemical compositions were included in this study. Forty disk shaped specimens of bis-acryl composite provisional material were prepared and divided into 4 groups according to the bonding agents. Control group didn't have bonding agent. Through the Teflon mould with 4.0 mm diameter hole with 4.0 mm thickness the same bis-acryl composite provisional material was added on the disks after the surface of each specimen was treated with designated bonding agent according to the manufacturer's instructions. Shear bond test was performed and the fractured surfaces were inspected with a microscope. One-way analysis of variance was conducted and the result was further analysed with Turkey post hoc test at the significance level of 0.05. Results: The highest strength was acquired from the specimens bonded with chemical cure system and it was statistically significant (P < 0.05). This group showed 100% cohesive failures. The lowest bonding strength was recorded from the specimens used conventional light cure bonding agent, and this group's result was similar with the control group. The group used a light cure bonding agent claiming improved compatibility revealed significantly higher bond strength to the traditional light cure bonding agent group in a statistically significant way (P = 0.043). Conclusion: According to the bonding agent used the shear bond strength was significantly affected. Therefore the choice of proper bonding agent is important when hiring a bonding agent to add bis-acryl composite provisional materials.

• Food Science and Preservation
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• v.13 no.1
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• pp.95-101
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• 2006

Quality characteristics of Cheongbukjangs with $1\~3\%$ desalted and dried sea tangle powder were investigated after fermentation for 48 hr at $40^{\circ}C$. Addition of sea tangle, irrespective of concentration, did not affect pH and slime content of Cheongbukjang. Color L* and a* values were generally decreased with increasing sea tangle concentration. There were no significant differences in total microbe, amino nitrogen content, and protease and amylase activity between control and Cheongbukjangs with up to $2\%$ sea tangle. However, addition of $3\%$ sea tangle resulted in decreased total microbe, amino nitrogen content, and enzyme activity compared with those of control. Fiber content increased with increasing sea tangle concentration and hardness increased by 1.5 times at $2\%$ sea tangle and by 2.6 times at $3\%$ sea tangle compared with that of control. Results for sensory evaluation revealed that addition of $2\%$ sea tangle was the optimum concentration in view of reducing bitter taste and odor, and improving overall acceptability.

• Food Science and Preservation
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• v.17 no.6
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• pp.814-819
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• 2010

We investigated quality changes in dumpling shells prepared using various concentrations of Enteromorpha intestinalis powder(EIP). Dumpling shells were prepared by addition of 0%, 3%, 5%, 7%, and 9%(all w/w) EIP to the flour used in the basic formulation. The gelatinization temperature of the EIP-wheat flour composite increased whereas initial viscosity at $95^{\circ}C$, viscosity at $95^{\circ}C$ after 15 min, and maximum viscosity, all fell with increasing EIP content, as measured by amylography. In addition, the Hunter's color L, a, and b values decreased significantly with increasing amounts of EIP. All of cooked weight, cooked volume, and water absorption of dumpling shells prepared with EIP were significantly greater than control values. In terms of textural characteristics, addition of EIP increased hardness, springiness, and chewiness, but decreased adhesiveness and cohesiveness. Sensory evaluation showed that dumpling shells prepared with 5% (w/w) EIP were preferred.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.6
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• pp.869-874
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• 2005

The purpose of this study was to determine the qualities of loaf breads added with green tea powder, minimum fermented tea powder (fermented for 10 hrs), medium fermented tea powder (fermented for 17 hrs), and black tea powder (fermented for 24 hrs). The moisture content of loaf bread added with green tea and three types of fermented tea was $36.02\~36.44\%$ and was similar to the control group of $36.98\%$. The content of crude protein and ash of loaf bread added with green tea powder and fermented tea was higher than that of control group. The water holding capacity of loaf bread added with green tea powder was the highest and was followed by the fermented tea added group and the control group. The volume and specific volume of loaf bread were high in tile order of the control group, the fermented tea added group, the green tea added group. The lightness of loaf bread got lower, while the redness and the yellowness of the bread 9ot higher as loaf bread was added with more fermented tea. The hardness of loaf bread get higher, but the cohesiveness got lower as loaf bread was added with the more fermented tea. The gumminess and chewiness of loaf bread added with black tea powder were the highest. The result of sensory evaluation of the loaf bread showed that the preference of the color was tBle highest in the control group, while the preference of the flavor and the taste was the highest in the green tea group and the minimum fermented tea group. The preference of overall acceptability of loaf bread was the highest in the minimum fermented tea group.