• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.41-41
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• 2012

고급 스포츠웨어와 이너웨어 등에 많이 사용되고 있는 나일론/폴리우레탄 혼방제품은 염색에 있어서 Grin-through 현상, 인공피혁의 염료 이염 현상 등 많은 문제들이 존재한다. 본 연구의 나일론과 폴리우레탄 복합소재에서 나타나는 염색거동을 고찰하고 분석하여, 폴리우레탄 복합소재의 염색성을 개선하기 위하여 실시하였다. 폴리우레탄 복합소재는 해성분이 용출되지 않은 나일론 초극세사 소재에 폴리우레탄 수지를 함침하여 인공피혁과 같은 느낌을 주도록 직접 제조하였다. 제조된 폴리우레탄 함침 나일론 초극세사 소재의 해성분을 용출하였고, Red 색상의 밀링형 산성 염료, 함금속 염료와 반응성 염료에 따라 달라지는 염색특성 및 세탁 견뢰도 등을 고찰하였다. 본 연구를 통하여 다음과 같은 실험결과를 얻을 수 있었다. 나일론 초극세사와 폴리우레탄 수지를 준비하여 습식공정을 통해 인공피혁을 제조한 함침 소재를 알칼리 감량하였고, 감량률은 15~17% 정도로서 대부분의 해성분이 용출됨을 확인하였다. PPG와 PTMG로 구성된 폴리올을 기반으로 한 폴리우레탄 함침 피혁과 PTMG를 단독으로 사용한 함침 피혁의 염색성을 비교한 결과, PPG+PTMG 타입이 더 우수한 염색성을 나타내었다. 특히 밀링 타입과 함금속 타입 염료의 경우는 거의 2배 이상의 흡진율과 겉보기 색농도를 나타내었다. 한편, 반응성 염료의 경우는 두 종류의 폴리우레탄 필름에 거의 염착되지 않았기 때문에 앞으로의 염색실험에서 제외하였다. 견뢰도 측면에서는 각각의 피염물의 등급은 거의 유사하게 나타남을 확인하였다. 이상과 같은 결과로부터, 인공피혁 제조시 PPG+PTMG 타입의 폴리우레탄 수지를 사용하여 함침시 더 높은 색강도와 염착률을 얻을 수 있음을 알았다. 사용하는 염료의 종류를 좀 더 다양하게 하여 실험을 실시하고 폴리우레탄의 물성 및 분석 등의 추가적인 연구가 진행된다면, 인공피혁의 염색시에 발생하는 여러 가지 문제점들을 해결할 수 있을 것이다.

• Membrane Journal
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• v.28 no.3
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• pp.205-213
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• 2018

In this study, cross-linked membrane were successfully prepared by using brominated PPO (Br-PPO) as the main polymer chain. Chitosan and quaternary ammonium modified chitosan (QA-chitosan) was used as the cross linking agents. The cross linked membranes were post-functionalized by using trimethylamine solution. The degree of cross linking was also controlled by varying the ratio of cross linking agent. The applicability of the cross-linked membrane (A-PPO + chitosan, A-PPO + QA-chitosan) as ion exchange membranes was verified through various characterization techniques. The cross-linked membrane using QA-chitosan as cross linking agent was found to be better in performance than the membrane using pristine chitosan cross linking agent. As the percentage of QA-chitosan increased, the ion exchange capacity from 1.18 meq/g to 1.53 meq/g and water uptake from 21.6% to 42.2% was improved.

• Journal of the Mineralogical Society of Korea
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• v.14 no.1
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• pp.39-51
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• 2001

공주군 유구면 일대의 화강암질 편마암의 풍화작용에 따른 원소의 거동과 pH와 이차광물과의 관계를 XRF, ICP-AES, ICP-MS를 이용한 원소분석결과를 통하여 검토하였다. 이 지역의 암석은 pH6 내외의 산성환경, 침철석, 아나타제와 같은 다양한 이차광물을 생성하면서 심각한 화학조성의 변화를 초래했다. 주원소의 화학조성을 이용한 풍화지수는 토양층에서 79~88로 모암 중의 사장석이 용해되고 흑운모가 변질되어 캐올리광물의 생성이 활발한 방향으로 풍화작용이 진행되었다. 지표층으로 가면서 Al에 대한 주 원소의 거동은 Si, Ca, Na, K, P가 감소하고 Fe, Ti, Mn이 증가하는 경향을 보이며 pH가 낮은 풍화단면에서 주 원소의 변화량이 더 크다. 이 풍화대에서 Mg은 거의 일정하다. Li, As 모든 전이원소는 pH가 감소함에 따라 증가하며 특히 이들 원소는 Fe의 함량과 비례해서 증가해 침철석과 공침하였거나 표면에 흡착되어 있는 것으로 보인다. Ga은 Fe와 비례하기는 하지만 변화량은 전 풍화단면에서 일정하다. Zr, Mo, Sn, Cd은 pH에 변화에 상관없이 일정한 반면에 Rb, Sr, Ba, Y, Pb, Th, U 등은 감소하는 경향을 보인다. 특히 Rb 과 Sr은 Ca에 비례해서 감소한다. 희토류원소는 전 풍화단면에서 감소하는 경향을 보이는데 $Al_2$$O_3$에 대한 상대적인 변화량을 보면 경희토류원소는 사프롤라이트(saprolite)하부와 상부에서 부화되어 있고 중부 사프롤라이트와 토양층에서 감소하는 반면에 중희토류원소는 사프롤라이트 하부와 상부에서 감소하고 중부사프롤라이트 및 토양층에서 부화되는 경향을 보인다. 전반적으로 희토류원소의 원자번호가 클수록 손실율이 커진다. 이 풍화단면에서 원소의 거동은 각 풍화층의 pH와 생성된 이차광물의 조성에 지배를 받았다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.6
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• pp.113-120
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• 2007

For the cases of constructing reinforced earth and gabion walls on the soft ground, an appropriate replacement area of soft ground required to maintain the stability of walls was investigated by FEM analyses. Incremental analyses were performed in FEM, in which construction sequences including consolidation of soft soil layer were simulated. As a first step to suggest the appropriate replacement area, a series of analyses for cases varying the replacement depth were conducted to examine the behaviors of wall and adjacent ground according to the construction sequence. The analysis results were, then, evaluated with the proper limiting values of displacements of wall, settlements and shear strains of ground to guarantee the stability of walls, which were specified based on the literature review. Consequently, the typical construction drawings could be suggested, in which appropriate replacement areas for varying wall heights for the ground condition investigated in this study were represented in terms of the ratio of replacement depth to the height of wall.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.693-703
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• 2017

Rover wheel's mobility depends on soil's condition and wheel's design. The purpose of this study is to evaluate the effect of soil conditions, which are Jumunjin sand and Korean lunar soil simulant (KLS-1), on wheel's motion performance. The experiments were performed by using a single wheel testbed with a wheel which grouser height is 15mm on Jumunjin sand and KLS-1, respectively. Also the influence of grouser length to wheel's mobility performance was studied. The experimental results of torque, drawbar pull and sinkage relating to slip ratio were discussed and analyzed to evaluate wheel's motion performance. Results showed wheel moving on KLS-1 has high performance than Jumunjin sand. Wheel's mobility performance was influenced by soil's properties of cohesion and frictional angle. In addition, wheel's performance of drawbar pull and Torque increased with the increasing of grouser length.

• Journal of the Korean GEO-environmental Society
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• v.13 no.4
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• pp.93-104
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• 2012

Efforts to understand and develop reasonable analysis methods for the uncertainty of ground have been made since the 20th century, and the concept of safety factor has been used. However, this concept has limitation in measuring the relative reliability of ground structures because the representative values of the actually used factors have uncertainty. Nevertheless, there is no method to completely remove uncertainty. In most cases, the ground investigation results in Korea are not enough for applying such statistical methods. Furthermore, performing a design without accurate investigation of consolidation state even though consolidation characteristics such as settlement and consolidation velocity vary greatly by the consolidation history can lead to many problems. Therefore, in this paper, as part of the effort to reduce the uncertainty of design around over consolidation ratio among the consolidation factors, the consolidation state was assessed on the basis of the results of high-quality laboratory tests that were performed in Gwangyang and Busan in the southern coast of Korea. Furthermore, consolidation characteristics such as over consolidation ratio by depth were proposed for different regions through statistical processes such as the test of normality and the removal of abnormal values to reduce the uncertainty of design parameters.

• Journal of the Korean Geotechnical Society
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• v.32 no.11
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• pp.97-108
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• 2016

Lunar rover plays an important role in lunar exploration. Especially, performance of rover wheel related to interaction with lunar soil is of great importance when it comes to optimization of rover's configuration. In this study, in order to investigate the motion performance of lunar rover's wheel on Korean Lunar Soil Simulant (KLS-1), a single wheel testbed was developed and used to carry out a series of experiments with two kinds of wheel with grousers and without grousers which were used to perform the experiments. Wheel traction performance was evaluated by using traction parameters such as drawbar pull, torque and sinkage correlated with slip ratio. The results showed that the single wheel testbed was suitable for evaluation of the performance of wheel and rover wheel with grousers which was likely to have higher traction performance than that without grousers in Korean Lunar soil simulant. The experimental results could be utilized in verification of the optimum wheel design and effectiveness of wheel traction for Korean lunar rover.

• Journal of the East Asian Society of Dietary Life
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• v.9 no.3
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• pp.370-375
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• 1999

This study was attempted to examine the sensory quality, the degree of gelatinization, color, texture and moisture content of Paeksulgies made with black color rice. The results were as follows: The moisture contents was about 32-36%. L-value on the control group was high, 94.74 and $A_1$, $A_2$, and $C_1$ group were 78.72, 78.58, and 78.43 respectively. As the amount of color rice was increased, L-value on the Paeksulgis was decreased. The gelatinization of Paeksulgis added with color block rice was most increased at C group and D group. In sensory quality. Paeksulgis added with 4-10% block color rice showed the most favorable sensory evaluation.

• Journal of the Korean Geotechnical Society
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• v.37 no.10
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• pp.27-40
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• 2021

The construction method to prevent the frost heave or thaw settlement is called the ground stabilization method, and the thermo-syphon is one of the typical ground stabilization methods. The thermo-syphon has recently been developed with a simple analysis model and thermal analysis has been carried out, but the frost heave of frost susceptible soil was not considered. This study was conducted using ABAQUS internal user subroutine to develop the numerical analysis model (Coupled thermo-mechanical) that can simultaneously perform thermal analysis for the temperature change of the soil according to the thermo-syphon and structural analysis to predict the frost heave of the soil accordingly. As a result of the numerical analysis, the frost heave of the soil decreased as the performance of the thermo-syphon increased. As for the main results, when the thermo-syphon which has contain 25%, 50%, and 100% of refrigerant filling ratio was applied, the reduction ratio of the frost heave was 5.5%, 14.4%, and 21% respectively.

• Tunnel and Underground Space
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• v.31 no.1
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• pp.25-40
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• 2021

As the era of Industry 4.0 arrives, the researches using artificial intelligence in the field of rock engineering as well have increased. For a better understanding and availability of AI, this paper analyzed the types of algorithms and how to apply them to the research papers where AI is applied among domestic and international studies related to tunnels, blasting and mines that are major objects in which rock engineering techniques are applied. The analysis results show that the main specific fields in which AI is applied are rock mass classification and prediction of TBM advance rate as well as geological condition ahead of TBM in a tunnel field, prediction of fragmentation and flyrock in a blasting field, and the evaluation of subsidence risk in abandoned mines. Of various AI algorithms, an artificial neural network is overwhelmingly applied among investigated fields. To enhance the credibility and accuracy of a study result, an accurate and thorough understanding on AI algorithms that a researcher wants to use is essential, and it is expected that to solve various problems in the rock engineering fields which have difficulty in approaching or analyzing at present, research ideas using not only machine learning but also deep learning such as CNN or RNN will increase.