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페니토인-${\beta}$-시클로덱스트린 포접 복합체의 좌제에 관한 연구
차재호,한건,Cha, Jae-Ho,Han, Kun 한국약제학회 1988 Journal of Pharmaceutical Investigation Vol.18 No.1
An inclusion complex of phenytoin (PT) with ${\beta}-cyclodextrin\;({\beta}-CyD)$ in molar ratio of 1 : 1 was prepared, and the interaction between host and guest molecules was confirmed by infrared spectrometry, differential scanning calorimetry and X-ray diffractometry. Suppositories were prepared by the fusion method. PT and $PT-{\beta}-CyD$ complex were added to PEG 1540 and Witepsol H-15 under the vigorous stirring at $40^{\circ}C$. Content uniformity was tested for different formulations of the PT suppositories. The release rates were dependent on the K.P. V dissolution apparatus and the dialyzing tubing method. Then, the release rates were increased in the following order: $PT-{\beta}-CyD$ complex in PEG 1540>PT in PEG 1540>$PT-{\beta}-CyD$ complex in Witepsol H-15>PT in Witepsol H-15. The area under the curve and maximum blood concentration after rectal administration were increased in the following order: $PT-{\beta}-CyD$ complex in PEG 1540>PT in PEG 1540>$PT-{\beta}-CyD$ complex in Witepsol H-15>PT in Witepsol-15.
미시역학적 파손 기준을 이용한 탄소섬유/에폭시 복합재 링크의 안전성 평가
차재호,윤성호,Jae Ho Cha,Sung Ho Yoon 한국복합재료학회 2023 Composites research Vol.36 No.3
본 연구에서는 경량화를 위해 금속 링크를 탄소섬유/에폭시 복합재 링크로 대체하고자 파손 기준을 이용하여 복합재 링크가 주어진 하중 조건을 견딜 수 있는지를 평가하였다. 복합재의 파손 양상을 예측하기 위해 MMF 기준을 이용하였고, 기계적 시험을 수행하여 MMF의 기준 강도 파라미터를 구하였다. 연구결과 링크의 구멍 주위에서 응력집중이 발생하였고, 특히 굽힘 하중을 받을 때 링크 끝단과 구멍 주위에서 취약함이 드러났다. 파손 지수로부터 파손 양상을 예측하였고 매트릭스 인장 파손이 링크 끝단에서, 그리고 구멍 주위에서는 섬유의 압축 파손이 예측되었다. 본 연구를 통해 확보된 방법과 결과는 경량화를 위해 금속 부품을 탄소섬유/에폭시 복합재로 대체할 때 특정 하중 조건 하에서 복합재의 안전성을 평가하는 유용한 지침으로 활용할 수 있을 것이다.
차재호(JAE-HO CHA),정일봉(IL-BONG CHUNG),이재훈(JAE-HUN LEE),선정훈(JEONG-HUN SUN) 한국철도학회 2014 한국철도학회 학술발표대회논문집 Vol.2014 No.10
현재 대부분의 역에서는 편리한 곳에서 승하차가 집중적으로 이루어지는 현상이 있다. 그로 인해 정차시간이 길어져 사회적 비용손실이 발생되고 있다. 본 논문에서는 승강장구조에 따라 승객이동과 집중이 다르게 나타나고 있다는 것을 보여준다. 또한 구조변경에 의해 승객분산과 표정속도 증가가 가능하다는 것을 설명한다. 본 논문으로 앞으로 건설될 도시철도 및 철도역사에 도움이 되고자 한다. Currently, in the most station of urban railway, the majority of passengers concentrated at more convenient spot for them to transfer causes train stopping-time delays and much social costs This study proves that passengers overcrowding and movements are depending on station`s. structures, and even a simple modification of platform structure would effect the dispersion of passengers and improve the train`s scheduled-speed. Therefore, a newly designed platform . (tentatively named Fan-shaped platform) can expedite passengers movements and also lessen overcrowding of passengers. We believe that this thesis will be helpful in urban railway industry and railway stations to be constructed.
동적기계분석장치를 이용한 탄소섬유/에폭시 복합재의 장기 성능 예측
차재호 ( Jae Ho Cha ),윤성호 ( Sung Ho Yoon ) 한국복합재료학회 2019 Composites research Vol.32 No.1
This study focused on the prediction of the long-term performance of carbon fiber/epoxy composites using Dynamic Mechanical Analysis (DMA) and Time-Temperature Superposition (TTS). Single-frequency test, multifrequency test, and creep TTS test were performed. A sinusoidal load of 20 μm amplitude was applied while increasing the temperature from -30oC to 240oC at 2oC/min for the single-frequency test and the multi-frequency test. The frequencies applied to the multi-frequency test were 0.316, 1, 3.16, 10 and 31.6 Hz. In the creep TTS test, a stress of 15 MPa was applied for 10 minutes at every 10oC from -30oC to 230oC. The glass transition temperature was determined by single-frequency test. The activation energy and the storage modulus curve for each temperature were obtained from glass transition temperature for each frequency by the multi-frequency test. The master curve for the reference temperature was obtained by applying the shift factor using the Arrhenius equation. Also, TTS test was used to obtain the creep compliance curves for each temperature and the master curve for the reference temperature by applying the shift factors using the manual shift technique. The master curve obtained through this process can be applied to predict the long-term performance of carbon fiber/epoxy composites for a given environmental condition.