• Proceedings of the Membrane Society of Korea Conference
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• 1998.04a
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• pp.65-67
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• 1998

1. 서론 : 내용매성, 내약품성 및 내열성 등이 탁월한 결정성 고분자를 소재로 하여 우수한 성능의 분리막을 제조하기 위하여 열유도 상분리법이 제안되었다. 열유도 상분리법은 먼저 고분자를 희석제와 함께 melt-blending하여 단일상의 균일한 용액을 만들고 이를 냉각시킴으로써 상분리가 일어나도록 유도하는 공정이다. (생략)

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.64-65
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• 1994

근래 환경 문제의 중요성이 크게 대두되면서 여러 제조 공정에서 방출되는 폐수등을 처리하는데 필요한 내구성이나, 내미생물성, 내약품성이 우수한 분리막 재료에 대한 연구가 진행되고 있다. 내구성이 우수한 역삼투막 재료를 얻기 위한 방법의 하나로 엔지니어링 플라스틱을 친수화시키는 방법이 개발되어 왔다. 특히 PPO (poly(2-6-dimethyl-1,4-phenylene oxide))로 만들어진 분리막은 내산화성이 우수하고 내구성이 뛰어나다고 알려져왔고 본 연구에서는 PPO에 carboxyl기를 도입하여 친수성을 부여하고, 상전이법을 이용하여 얇은 표피층이 선택성을 높이고 다공성 구조가 표피층을 지지하도록 만든 비대칭성 구조의 분리막을 제조하고 그 투과특성을 살펴보았다.

• Proceedings of the Membrane Society of Korea Conference
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• 1991.04a
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• pp.40-42
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• 1991

최근에 분리 농축 그리고 정제 등의 분야에서 세라믹 분리막은 내열성, 내약품성 및 우수한 기계적 강도와 같은 특성으로 인해 기존의 유기고분자막으로는 사용할수 없던 영역까지 그 응용 범위를 확대시키고 있다. 이러한 세라믹 분리막 중 기공크기가 0.1-0.001 $\mu$m 정도로 미세한 한외여과막의 경우, 최근에는 주로 졸-겔법을 이용하여 제조되는 것으로 보고되고 있는데, 이는 졸-겔법이 기존 분리 공정과 비교하여 볼대 다음과 같은 장점이 있기 때문이다.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.183-188
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• 1996

The durability of concrete structures decrease due to deterioration of concrete when they are constructed in marine or pollutional environments. In this study, the mortar specimens made from the five different types of cement were immersed in artificial seawater and four kinds chemical solution, and were measured the change of compressive strength and weight. The results show that the longer the immersed days are, the more the compressive strength reduction is. It has been remarked that the resistance of slag cement and ground granulated blast-furnace slag is excellent in chemical attack.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.207-210
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• 2001

폴리비닐알코올(poly(vinyl alcohol) ： PVA)은 우수한 기계적 성능과 계면특성 및 내약품성 등을 가진 고분자로서 호제, 의류나 산업용 섬유, 편광 및 포장용 필름, 분리용 필터 및 의학용 고분자에 이르기까지 광범위한 활용 범위를 갖는다 비닐알코올(vinyl alcohol)의 호변이성질화[1] 때문에 단량체의 직접중합에 의해서는 얻을 수 없는 PVA는 분자량, 비누화도 및 입체규칙성 정도에 따라 물성이 크게 변화하므로, 이에 따른 표면특성의 변화 정도를 종합적으로 검토할 필요성이 제기되고 있다. (중략)

• Journal of Digital Convergence
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• v.14 no.10
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• pp.507-514
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• 2016

This study was to find out relations among sports values of participants in sport for all, satisfaction of participation and intention to adhere to exercise. Objects of study were participants in sport for all and data had been collected by convenience sampling method. Among 250 copies of data, 233 copies had been used for final analysis. Collected data had been analyzed with frequency analysis, correlation analysis, multiple regression analysis by using of SPSS 21.0. The results from those processes are as below. First, value of personality, physical value, psychological value, and social value have positive effects on satisfaction of participation. Second, value of personality, psychological value, value of entertainment and physical value have positive effects on intention to adhere to exercise.

• The Journal of the Korea Contents Association
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• v.16 no.9
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• pp.78-84
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• 2016

Weapon, command, and communication system have been continually developed in the Korean military since last several decades. However, it is always asked to make a more effort on improving the ability of combat capability through people in order to achieve and maximize military power. In terms of improving the battlefield leadership, this research focused on ROTC(Reserve Officers'Training Corps), because the training junior officers lays a great foundation on basic strength of the military. This study theoretically and empirically examined the ROTC's quality and effectiveness of leadership. The proposed research model and hypotheses are mainly composed of four factors: personality, esprit de corps, and professionalism as independent variables; leadership effectiveness as a dependent variable. The empirical result revealed that esprit de corps, professionalism, and personality have a meaningful influence on leadership effectiveness. It is suggested that an ongoing training and education program of leadership for ROTC should be applied for achieving a better leadership effectiveness on the battlefield.

• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.451-458
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• 2014

Waterborne polyurethane dispersion (WPUD) was prepared from polycarbonate diol (PCD), isophorone diisocyanate (IPDI) and dimethylol propionic acid (DMPA) as starting materials. Then, waterborne acrylic polyurethane dispersion (AUD) was synthesized by reacting the WPUD with different types of acrylate monomers, such as methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA) and butyl acrylate (BA). Subsequently, the AUD was mixed with multi-walled carbon nanotube (MWCNT) to yield a conductive coating solution, and the mixture was coated on the polycarbonate substrate. The pencil hardness, abrasion resistance and chemical resistance of the coating films from AUD were improved than those from WPUD, while the electrical conductivity of the coating films from AUD was decreased than that of WPUD. Also, the effect of acrylate types on the properties of coating films was investigated. The AUD obtained from HEMA showed the strongest pencil hardness, while the AUD obtained from MMA exhibited the strongest abrasion resistance, chemical resistance and electrical conductivity among several types of acrylate monomers.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.73-79
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• 2013

Waterborne polyurethane dispersion (WPUD) was synthesized from polycarbonate diol (PCD), isophorone diisocyanate (IPDI) and dimethylol propionic acid (DMPA) as starting materials. Then, waterborne acrylic polyurethane dispersion (AUD) was synthesized by reacting the WPUD with an acrylate monomer, methyl methacrylate (MMA). Subsequently, the AUD was mixed with multi-walled carbon nanotube (MWCNT) to yield a conductive coating solution, and the mixture was coated on the polycarbonate substrate. With increasing the amount of MMA in the AUD, the pencil hardness, abrasion resistance and chemical resistance of the coating films were improved, but the electrical conductivity of the coating films was decreased. On the other hand, the pencil hardness, abrasion resistance and chemical resistance of coating films were decreased, but the electrical conductivity was enhanced with increasing the amount of MWCNT in the conductive coating solutions.

• KSBB Journal
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• v.11 no.4
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• pp.481-488
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• 1996

In spite of diverse applications of chitin derivatives, commercial use of chitin has been limited due to highly resistance to chemicals and the absense of proper solvents. One of methods to reduce such high resistance to chemicals is to make microcrystalline chitin(MCC) by hydrolysis of chitin. Presently, MCC is produced mainly by using high concentration of acid, but this treatment requires an extensive posttreatment to remove or recover acid. An alternative process for MCC production was developed by using dilute hydrochloric acid with ultrasound and hydrogen peroxide. The major parameters for this process were found to be acid concentration, swelling time and temperature, and irradiation time and frequency of ultrasound. The effects of these parameters on MCC molecular weight were investigated. The molecular weight of MCC produced at a typical condition was around 30,000 which was approximately 1/8 of that of chitin and approached to a constant value. This phenomenon was explained by introducing the model of molecular arrangement of cellulose. SEM analysis showed that both chitin and MCC had a fibrous shaped morphology and the fibril size of MCC was much smaller than that of chitin.