• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06d
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• pp.1-4
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• 1998

본 논문에서는순수 압전세라믹에 비해 동등이상의 압적특성을 가지면서도 음향임피던스가 월등히 낮은 1-3형 압적복합체를 이용한 탐촉자의 개발에 관해 연구하였다. 압전 복합재료 탐촉자는 그 자체만으로 측정대상체와의 음향임피던스 차를 최소화하여 별도의 정합층을 필요로 하지 않는 특징을 가진다. 이를 위하여 본 연구에서는 복합재료에 사용되는 고분자재료의 물성값 설계와, 압전세라믹과의 적절한 배합구조와 형상의 결정에 주안점을 두었다. 그 결과를 바탕으로 압전 복합체 초음파 트랜스듀서 시작품을 제작하고 그성능을 분석하였으며, 이론적인 시뮬레이션 결과과의 비교를 통해 설계이론의 타당성을 검증하였다.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.41-49
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• 2009

Cement concrete pavement has become more common in Korean highway systems. However, as its service period increases, there are some technical problems occurs and no clear solution is available primarily due to the lack of active researches. This research, hence, aims to develop a new mix proportion that may provide better strength and durability with extended service life. Based on a variety of literature reviews, the experimental variables were determined as unit cement content, S/a ratio and W/C ratio. From the experimental works, it is recommended to increase the unit cement content up to 375kg/$m^3$, 400kg/$m^3$ and 425kg/$m^3$. The target slump and air content were set 40mm and 5%, respectively. The maximum size of coarse aggregate was decided to be 25mm because of the easiness of supply in the field. The reduction of W/C ratio was necessarily required and decreased to 0.4 which was proven not to cause any mixing problem with the increased unit cement contents along with polycarbon-based high range water reducing agent. In addition, it was known that the S/a ratio could be reduced to 0.34. The lowered S/a might be possible because of the increased cement paste and hence increased cohesiveness and workability.

• Journal of the Korean Geosynthetics Society
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• v.15 no.1
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• pp.21-35
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• 2016

It is a current trend that the concrete track is applied for high speed railway. In the case of the railway embankment constructed on soft ground, the damage to concrete track which is sensitive to settlement such as distortion and deflection could be caused by very small amount of long term settlement. Pile Supported Embankment method can be considered as the effective method to control the residual settlement of the railway embankment on soft ground. The Geosynthetics is used inside of the embankment to maximize the arching effect transmitting the load of the embankment to the top of the piles. But, PHC piles that are generally used for bridge structures are also applied as the pile supporting the load of embankment concentrated by the effect of the Geosynthetics. That is very low efficiency in respect of pile material. So, in this study, the cast in place concrete pile was selected as the most suitable pile type for supporting the embankment by a case study and the optimum mixing condition of concrete using a by-product of industry was induced by performing the mixing designs and the compressive strength designs. And it is shown that the cast in place pile with the optimum mixing condition using the by-product of industry is 2.8 times more efficient than the PHC pile for the purpose of Pile Supported Embankment by the finite element analysis method.

• Journal of the Korea Concrete Institute
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• v.26 no.6
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• pp.679-686
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• 2014

In this research, the mix proportion of the antiwashout underwater concrete with the mineral admixture was evaluated. It can reduce the amount used of the antiwashout admixture (hereinafter referred to as "AWA") and satisfy the properties of concrete. In addition, the review for the difference of the test and practical affairs were conducted. Optimized unit quantity of water of antiwashout underwater concrete and the amount used of AWA was revealed by $190kg/m^3$, 0.9%/W, respectively. In particularly, the mix design is reduced by 5% than the W/B of target strength even though the W and AWA reduced. Therefore, it will have the economical feasibility and qualities including the material separation, resistance characteristic and compressive strength, and etc. The stable value was shown in 1 point of minute passed in the measurement of the turbidity amounts using the turbidimeter after the checker insertion. However, it needs to be reviewed for the interrelationship between turbidity measuring machine and KCI-AD102 standard method. There were no significant differences of compressive strength of specimens in the water depending on the production methods.

• Korean journal of food and cookery science
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• v.19 no.6
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• pp.685-693
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• 2003

The aim of this study was to develop a standardized recipe for black sesame gruel that has been preferred for generations as a nutritional food. The method focused on optimizing the mixing ratio of the components to improve the quality of the black sesame gruels that modem consumers would like. The results are summarized as follows: The more black sesame added to the gruel, the lower its brightness was, but the redness and yellowness was higher. The amount of black sesame made a significant difference in the viscosity, color, nutty taste, bitterness, appearance and overall preference. It was highest in the overall preference when the amount of black sesame was added 33g(40％ of rice weight basis). Different types of rice were added to the black sesame gruel, and it was observed that the color value of the gruel was high in its brightness, redness and yellowness when 50g(60％) of glutinous rice was added to it. The black sesame gruel was most preferred when 50g of non-glutinous rice was added. The redness value was high when 15g(18％) of non-glutinous rice flour was added. The yellowness value was high when 25g(30％) of non-glutinous rice flour was added. This observation showed significant differences in the viscosity, color, nutty taste, bitterness, appearance and overall preference. In particular, the black sesame gruel was most preferred when 50g of non-glutinous rice flour was added. The addition of 7g(9％) of salt to the black sesame gruel showed the highest brightness. The redness and yellowness was the highest when 5g(6％) of salt was added. This observation showed a significant difference in the viscosity, color, nutty taste, bitterness, appearance and overall preference. The highest preference was observed when 2.5g(3％) of salt was added. Adding more materials increased the viscosity of the black sesame gruel. With increasing temperature, the viscosity became lower, and vice versa. The intensity of sweetness and spreadability was found to be proportional to the amount of additive material. In conclusion, the optimum recipe for black sesame gruels was obtained 33g(40％) of black sesame, 50g(60％) of glutinous rice (flour), 2.5g of salt, and 500$m\ell$ of water.

• Polymer Science and Technology
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• v.20 no.5
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• pp.472-480
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• 2009

반도체 미세화가 진행되면서, 이를 성공하기 위해 많은 재료물질이 요구되어진다. 이 중 미세 패턴의 붕괴를 막고 깊은 패턴을 새기기 위해서 필요한 hardmask 재료가 있다. Hardmask는 유기실리콘 재료와 탄소 함량이 높은 재료로 주로 구성되고, 이들은 193 nm 빛과 관련된 광학적 특성을 가지면서 특정 플라즈마에 대한 에치 저항성을 가지는 물성을 가지도록 디자인/합성/배합되어져 있다. 또한, 접합되는 다른 박막과의 compatibility및 용매에 대한 solubility 등이 적절해야만 나노미터 수준의 defect 없는 패턴을 구현할 수 있다.

• 베이커리
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• no.12 s.389
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• pp.134-136
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• 2000

제품을 만드는 데 있어 크림의 역할은 대단히 중요하다. 풍미를 올려주고 식감을 좋게 하는데 없어서는 안 될 요소로 인식되고 있다. 이번 호에서는 생크림을 비롯한 각종 크림에 대해서 알아본다. 생크림에 첨가하는 재료와 그 사용법을 다양하게 살펴본다. 커스타드 크림의 어원과 배합을 알아보고 가나슈 크림의 성질과 용도를 함께 알아본다.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2009.10a
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• pp.235-240
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• 2009

• 한국도로학회:학술대회논문집
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• 2003.10a
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• pp.225-228
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• 2003

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.1
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• pp.81-87
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• 2020

Crack control is essential to increase the durability of concrete significantly. Healing of crack can be controlled by rehydration of unreacted clinkers at the crack surface. In this paper, by comparing the results of isothermal calorimetry test and regression analysis, the Parrot & Killoh's cement hydration model was verified and clink er hydration model was proposed. The composition and quantification of hydration products were simulated by combining kinematic hydration model and thermodynamic model. Hydration simulation was conducted using the verified and proposed hydration model, and the simulation was performed by the substitution rate of clink er. The type and quantity of the final hydration product and healing product were predicted and, in addition, the optimal cementitious material of self-healing concrete was selected using the proposed hydration model.