철도차량의 충돌 원인 탈선거동 예측을 위한 윤축모델 연구

최세영(Se-Young Choi),구정서(Jeong-Seo Koo),유원희(Won-Hee You) 한국철도학회 2010 한국철도학회 학술발표대회논문집 Vol.2010 No.10

철도차량 충돌에 의한 타고오름 탈선거동 예측을 위한 단일윤축 이론모델 개발

최세영(Se Young Choi),구정서(Jeong Seo Koo),유원희(Won Hee You) 한국철도학회 2011 한국철도학회논문집 Vol.14 No.3

여고생의 사상체질 간 운동·식생활 습관

박서희(Seo Hee Park),최세영(Se Young Choi),고유선(You Sun Ko) 대한스포츠한의학회 2013 대한스포츠한의학회지 Vol.13 No.1

Objective This study is to examine exercise and eating habits according to female high school students sasang constitution. Method The Subjects are 339 students of girls high schools located in Seoul and Gunsan. For the classification of Sasang constitution, QSCCII was used. After the questionnaire survey was conducted targeting 261 students, apart from 78 students who were not classified among the subjects and crosstabulation analysis was performed to test the differences of exercise and eating habits by sasang constitution with SPSS 18.0 program. Result & Conclusion The results are as follows. First, the students of soeumin type is thought that their physical strength level was weak, compared with other two types and they were fat and usually felt tired. Second, the students of taeeumin type is thought that they were fat, compared with other two types and did not take nutritional supplements well. On the other hand, the students of soyangin type is thought that they had normal body shapes. Third, there were no significant differences in food intake patterns according to sasang constitution, but female high school students generally preferred eating vegetables. In eating meat, overall, they much preferred eating pork and chicken, but the preference for fish was relatively low. The above results show that there are differences in exercise and eating habits and can be provided as basic research materials for the development of proper living habits education program.

폴리에스터계 열가소성 탄성체의 합성 및 물성연구

최교창(Kyo Chang Choi),이은경(Eun Kyoung Lee),최세영(Seo Young Choi),박수진(Soo Jin Park) 한국공업화학회 2002 공업화학 Vol.13 No.1

본 연구에서는 dimethyl terephthalate (DMT), 1,4-butanediol (1,4-BD) 그리고 분자량이 2000인 polytetramethylene glycol (PTMG)로부터 용융중 합법을 이용하여 폴리에스터계 열가소성 탄성체를 제조하였다. 결정성 영역인 DMT 및 1,4-BD의 경질성 분절과 PTMG의 연질성 분절을 변량 배합하여 합성한 폴리에스터계 열가소성 탄성체는 다양한 물성을 나타내었으며 고온에서의 열적 안정성 및 기계적 물성을 증대시키기 위하여 열처리를 하였다. Differential scanning calorimeter (DSC) 분석 결과, 열처리된 시료의 경우, 융점이 보다 고온으로 이동된 것으로 보아 고온에서의 안정성을 확인할 수 있었다. 또한, 굴곡강도 및 탄성을 시험으로부터 연질성 분절의 함량이 35 wt%인 경우가 최적의 물리적 가교점을 형성함으로써 가장 우수한 기계적 물성을 나타내었고, scanning electron microscopy (SEM) 분석으로부터 연질성 분절의 함량이 증가할수록 결정성 부분의 감소로 인한 열적특성과 기계적물성을 예측할 수 있었다. In this work, the poly(ether-b-ester) thermoplastic elastomers (TPEEs) were synthesized by a melt polymerization, using dimethyl terephthalate (DMT), 1,4-butanediol (1,4-BD), and polytetramethylene glycol (PTMG) having the molecular weight of 2000 (g/㏖). The TPEEs prepared with hard segment, combination of DMT and 1,4-BD, and soft segment, PTMG, indicated a variety of properties. To improve thermal stability and mechanical properties at elevated temperatures, the final copolymers were produced by thermal treatment. Differential scanning calorimeter (DSC) showed that the melting points of the annealed TPEEs shifted to higher temperature zones than those of the unannealed ones, leading to a better understanding of thermal stability at elevated temperatures. Moreover, it was shown that the copolymer of 35 wt% content soft segment had the most significant mechanical properties for flexural strength and elastic modulus in flexure. The decrease of the crystallizable region with increasing the soft segment content, which was confirmed by scanning electron microscopy analysis (SEM) enabled us to estimate the thermal and mechanical properties.

실란 커플링제로 처리된 실리카가 탄성에폭시의 경화온도 및 기계적 물성에 미치는 영향

최선미 ( Sun Mi Choi ),이은경 ( Eun Kyoung Lee ),최세영 ( Seo Young Choi ) 한국고무학회 2008 엘라스토머 및 콤포지트 Vol.43 No.3

본 연구에서는 실란 커플링제을 변량 배합하여 습식법과 건식법으로 실리카를 전처리하여 epoxy/carboxyl-terminated butadiene acrylonitirile (EP/CTBN) 복합체를 제조하였다. EP/CTBN 복합체의 경화특성 및 표면자유에너지, 인장강도 및 충격강도의 기계적 특성과 계면 특성을 건식법과 습식법에 따라 고찰하였다. Differential scanning calorimetry(DSC)의 결과 실란커플링제의 양이 증가함에 따라 실리카의 기공을 막아 경화제의 양을 증가시켜 경화온도가 감소되었으며, 건식법보다는 습식법이 EP/CTBN 복합체의 경화온도를 감소시킴을 알 수 있었다. 또한 실란커플링제의 양이 증가함 따라 표면자유에너지와 충경강도가 증가되었으나, 인장강도는 실란커플링제의 양이 4 wt%일 때 감소되었으며, 습식법보다는 건식법이 더 물성을 향상시킴을 알 수 있었다. In this work, epoxy/carboxyl-terminated butadiene acrylonitirile (EP/CTBN) composites were prepared by employing a reinforcing filler, silica treated with silane coupling agent in different ratio by dry and wet method. Their curing characteristics, surface free energy, interface morphologies and mechanical properties such as tensile strength and impact resistance were carefully investigated. Differential scanning calorimetry(DSC) results showed that curing temperature was lowered with the increase of silane coupling agent because of the increase of relative curing agent cotent by filling the pores of silica. Wet method was proved to be more effective for lowering curing temperature of EP/CTBN composite. In general, surface free energy and impact resistance were increased with the increase of silane coupling agent in this work. Tensile strength, however, was observed to be decreased at 4 wt% of silane coupling agent. It was found that the dry method was proved to be preferable for pretreatment of silica with coupling agent.

Fe3O4와 Chloroprene Rubber (CR)를 기초로한 탄성 전도체의 제조 및 특성연구

최교창 ( Kyo Chang Choi ),이은경 ( Eun Kyoung Lee ),최세영 ( Seo Young Choi ) 한국고무학회 2003 엘라스토머 및 콤포지트 Vol.38 No.1

본 연구에서는 FeCl_2 · 4H_2O, (CH_2)_6N_4 (hexamethylent tetramine) 그리고 NaNO_2로부터 Fe_3O_4 (magnetite)를 제조하고 결정성 CR고무에 배합하여 전도성 충전제의 함량이 물성에 미치는 효과와 전기전도도 (σ)의 온도 의존성을 조사하였다. 최소 최적 혼합비(percolation threshold, P_c) 개념이 본 연구에서 제조한 전도성 입자가 충전된 복합체에 적용되며, 혼합물내 Fe_3O_4의 분율이 27%를 초과할 때 전기전도도가 급격히 증가함을 확인하였다. 전기전도도의 온도 의존성은 P_c 또는 그 이하에서 열적으로 활성화되며 magnetite가 CR 고무의 강화 및 전도성 충전제로서의 역할을 할 수 있음을 조사하였다. 또한, 50 phr의 magnetite가 충전된 복합체가 최적의 물리적 가교점으로 인하여 가장 우수한 인장강도와 파단시 신장율을 보였으며 모듈러스가 magnetite의 강화효과 및 블랜드물의 가황 토오크 곡선으로부터 얻은 점도와 관련이 있음을 확인하였다. In this work, Fe_3O_4 (magnetite), conductive filler was prepared from FeCl_2 · 4H_2O, (CH_2)_6N_4 (hexamethylent tetramine), and NaNO_2, followed by mixing with crystallizable chloroprene rubber(CR). The influence of conductive filler content on the properties of the conductive composite was studied and temperature dependence of the electrical conductivity (σ) was also investigated. It is found that the percolation threshold concept holds true for the conductive particle-filled composite where σ indicates a nearly sharp increase when the fraction of magnetite in the mixture exceeds 27%. The temperature dependence of σ is thermally activated blelow or at the P_c. Magnetite acts as reinforcement and conductive filler for CR rubber. Moreover, it is shown that the composite with magnetite of 50 phr gives the most significant mechanical properties for tensile strength and elongation at break, which is due to the formation of optimum physical interlock and crosslinking. The results of 100%, 200%, and 300% moduli suggest that the moduli are related with reinforcement effect of magnetite and viscosity of the blend.

혼합 계면활성제를 이용한 Chlorosulfonated Polyethylene ( CSM ) Rubber 의 유화안정성 연구

이은경(Eun Kyoung Lee),최세영(Seo Young Choi),박수진(Soo Jin Park) 한국고무학회 2001 엘라스토머 및 콤포지트 Vol.36 No.4

N/A In this work, the stabilization of chlorosulfonated polyethylene (CSM) rubber emulsion with surfactants, i.e., nonionic (Span 60) or anionic (Sodium laurylsulfate, SLS) surfactants, was investigated. The phase inversion emulsification by interfacial chemical characteristics was used to emulsify the CSM rubber. As a result, the emulsion phase separation was observed in the case of any single surfactant. However, there was no phase separation in the mixture of Span 60 and SLS in the context of emulsion droplet size tests and rheological behaviors. The droplet size decreases by increasing the surfactant mixture, resulting in increasing the viscosity. The viscosity and shear stress determined from shear rate show a shear thinning and yield behaviors. It was then found that the emulsion stabilization can be improved using the phase inversion emulsification method and surfactant mixture.

자기 공진 결합 방식을 이용한 무선 전력 전송기술 구현을 위한 자기 공진기 소형화 설계

조영식,박지혜,남윤서,최세영,Cho, Young Seek,Park, Ji Hye,Nam, Yun Seo,Choi, Seyeong 한국정보통신학회 2014 한국정보통신학회논문지 Vol.18 No.8

A novel inductive resonator for the implementation of wireless power transfer using resonant inductive coupling is presented. The proposed inductive resonator is much smaller than the helix shape resonator suggested by MIT research team but operates the same resonant frequency with comparable wireless power transfer efficiency. The proposed inductive resonator is a spiral shape ($1,696cm^3$), which is 97 % smaller than the helix shape ($59,376cm^3$). The wireless power transfer efficiency is less than 9 % when compared to the helix shape resonator. With the reduce size and comparable efficiency, this novel inductive resonator can be used in practical application of wireless power transfer. 자기 공진 결합 (resonant inductive coupling) 현상을 이용한 무선 전력 전송 기술을 구현하기 위하여 새로운 구조의 자기 공진기를 제시한다. MIT 연구팀이 제안한 헬릭스 (helix) 모양의 자기 공진기의 크기를 줄이고, 공진 주파수 10 MHz를 유지하며, 무선 전력 전송 효율이 크게 열화 되지 않도록 설계한다. 새로운 구조의 자기 공진기는 스파이럴 (spiral) 모양으로써 헬릭스 모양 대비 소형화를 달성하였다. 스파이럴 모양 ($1,696cm^3$)의 자기 공진기는 헬릭스 모양 ($59,376cm^3$) 대비 97% 소형화를 이룩하였고, 무선 전력 전송 효율은 기존 기술 (2 m 거리에서 40 % 전송 효율) 대비 9% 이하로 차이를 줄임으로써 무선 전력 전송 기술의 실용화에 기여할 수 있게 되었다.

경운에 따른 논, 밭 토양비옥도 평가

조희래(Hee-Rae Cho),한경화(Kyung-Hwa Han),장용선(Yong-Seon Zhang),정강호(Kang-Ho Jung),서미진(Mi-Jin Seo),이영한(Young-Han Lee),최세영(Se-yeong Choi) 한국토양비료학회 2016 한국토양비료학회 학술발표회 초록집 Vol.2016 No.10

유화 Chlorosulfonated Polyethylene Rubber (CSM)의 제조 및 특성 연구

이은경,최교창,최세영 한국고무학회 2005 엘라스토머 및 콤포지트 Vol.40 No.1

본 연구에서는 CSM 에멀젼의 물성을 향상시키고자 금속성 가교제인 magnesium carbonate 및 calcium hydroxide를 첨가하여 가교밀도, 열적특성, 표면자유에너지 그리고 인장강도, 파단신율 및 인열강도 특성을 고찰하였다, 금속성 가교제인 magnesium carbonate 및 calcium hydroxide 양이 증가함에 따라 CSM 에멀젼 필름은 가교밀도는 증가하였고, 이에 내수성과 T_(g) 값도 증가하였다. 금속성 가교제로 magnesium carbonate를 첨가하였을 때 calcium hydroxide에 비해서 다소 높은 가교밀도와 T_(g) 값을 보였다. 하지만 CSM 에멀젼 필름의 표면에너지 및 기계적 특성들은 다소 다른거동을 보였다 Magnesium carbonate 0.75% 그리고 calcium hydroxide 1.0% 첨가한 경우가 가장 높은 표면 자유에너지 값과 인장강도 및 인열강도를 보였으나, 그 이상의 양을 첨가하였을 경우에는 오히려 감소함을 확인하였다. 그러므로 본 연구에서 CSM 에멀젼의 물성을 향상시키는데 적용되는 금속성 가교제로서 calcium hydroxide 보다 magnesium carbonate가 더 적당하며, 0.75% 첨가하였을 때 보다 향상된 물성을 얻을 수 있었다. In this work. magnesium carbonate and calcium hydroxide as metallic crosslinking agent were added to chlorosulfonated polyethylene rubber (CSM) emulsion to enhance the mechanical properties of emulsion film such as tensile strength. elongation at break, and tear strength and crosslinking density. thermal features, and surface energy were also investigated. Crosslinking density of the CSM emulsion film with increasing the amount of magnesium carbonate and calcium hydroxide increased. leading to the enhancement of water resistance. It was shown that compared with calcium hydroxide, magnesium carbonate had a little higher crosslinking density and To value. The surface energy and mechanical characteristics of the CSM emulsion film, however, showed somewhat different behaviors. The highest surface energy. tensile strength. and tear strength were observed when 0.75° o for magnesium carbonate and 1.0° o for calcium hydroxide were added respectively. Therefore. it can be concluded that as metallic crosslinking agent to improve water resistance and mechanical properties of the CSM emulsion, magnesium carbonate is more preferable to calcium hydroxide