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N-isopropylacrylamide의 그라프트에 의한 아크릴 섬유의 표면개질
우종형,서영삼,윤기종,Woo, Jong-Hyung,Seo, Young-Sam,Yoon, Kee-Jong 한국섬유공학회 2006 한국섬유공학회지 Vol.43 No.3
Acrylic fibers were graft-copolymerized with N-isopropylacrylamide in aqueous media, using a radical initiator, benzoyl peroxide. The grafting reactions were carried out within the $75{\sim}85^{\circ}C$ temperature range, and the effects of initiator, monomer concentration, and the amount of fiber on the graft yield were also investigated. The maximum graft yield of 88.6% was reached when grafting was carried out at the benzoyl peroxide concentration of $2{\times}10^{-3}mol/l$, the N-isopropylacrylamide concentration of 0.5 mol/l, for 8 hours at $80^{\circ}C$. The grafted fibers were characterized by nuclear magnetic resonance spectroscopy, infrared spectroscopy, scanning electron microscopy, and thermogravimetry. Scanning electron micrographs showed that homogeneous fiber surface changed to shell-like heterogeneous appearance with increase in degree of grafting. Fiber diameter also increased with graft yield. Moreover, moisture regain and water absorptivity of the grafted fiber were highly enhanced by grafting. The results on the response of grafted acrylic fibers to pH and heat are presented.
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Establishment of a mouse model of 70% lethal dose by total-body irradiation
류승현,박종형,정의숙,최수영,함승훈,박진일,전희연,김준영,유란지,이용진,우상근,최양규 한국실험동물학회 2016 Laboratory Animal Research Vol.32 No.2
Whereas increasing concerns about radiation exposure to nuclear disasters or side effects of anticancer radiotherapy, relatively little research for radiation damages or remedy has been done. The purpose of this study was to establish level of LD70/30 (a lethal dose for 70% of mice within 30 days) by total-body γ irradiation (TBI) in a mouse model. For this purpose, at first, 8-week-old male ICR and C57BL/6N mice from A and B companies were received high dose (10, 11, 12 Gy) TBI. After irradiation, the body weight and survival rate were monitored for 30 days consecutively. In next experiment, 5-week-old male ICR and C57BL/6N mice from B company were received same dose irradiation. Results showed that survival rate and body weight change rate in inbred C57BL/6N mice were similar between A and B company. In ICR mice, however, survival rate and body weight change rate were completely different among the companies. Significant difference of survival rate both ICR and C57BL6N mice was not observed in between 5-weekold and 8-week-old groups receiving 10 or 12 Gy TBI. Our results indicate that the strain and age of mice, and even purchasing company (especially outbred), should be matched over experimental groups in TBI experiment. Based on our results, 8-week-old male ICR mice from B company subjected to 12 Gy of TBI showed LD70/30 and suitable as a mouse model for further development of new drug using the ideal total-body irradiation model.
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복합중공사막 브레이드 지지체의 열처리에 따른 형태 변화
박홍원,김종훈,우종형,이호영,박성빈 한국섬유공학회 2023 한국섬유공학회지 Vol.60 No.3
The composite hollow fiber membrane is a ultra filtration made by coating apolymer mixture on the surface of the braid, which is a substrate. Compared to a singlemembrane, it has excellent strength, durability and life time. In this study, we tried todevelop a heat treatment method to flatten the surface of the braid used as a fiber supportfor the composite hollow fiber membrane and improve the circularity of the cross section. A heat treatment device capable of controlling temperature and take-up speed wasdevised, and braids were heat treated with various conditions. As a result of comparing surfaceand cross-section images, it was observed that the surface of the specimen treated at220 oC or higher was flattened by heat treatment and the cross-section became closer to acircular shape. And it was found that the lower take-up speed, the larger the diameterchange due to heat shrinkage.
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Dyadic Sorting 방법을 이용한 DT-MRI Regularization에 관한 연구
김태환(Tae Hwan Kim),우종형(Jong Hyung Woo),이훈(Hoon Lee),김동윤(Dong Youn Kim) 대한전자공학회 2010 電子工學會論文誌-SC (System and control) Vol.47 No.4
자기공명확산텐서영상(diffusion tensor magnetic resonance image, DT-MRI)으로부터 얻어진 확산텐서는 잡음에 민감하므로 주 고유벡터(principle eigenvector, PEV)의 필드에도 잡음이 포함되기 쉽다. 신경다발영상은 잡음에 매우 민감한 PEV로부터 얻어지기 때문에 실제 신경다발의 방향과 다를 수 있다. 따라서 잡음을 제거하기 위한 정규화(regularization) 과정이 필요하다. 본 연구에서는 고유값과 고유벡터를 정규화 하기 위한 방법으로 Dyadic Sorting(DS) 방법을 사용하였고 이를 구현하기 위한 알고리듬을 제시하였다. DS 방법은 3×3 화소에서의 고유값-고유벡터 쌍의 오버랩 정도를 측정할 수 있는 Intervoxel overlap function을 이용하여 고유값, 고유벡터를 재배열하는 방법이다. 본 연구에서는 이 방법을 3차원으로 적용하여 주 고유 벡터가 45°인 합성영상과 임상데이터에 적용하였고, 그 결과 임상데이터의 피질척수로에 적용한 경우 제안한 DS 방법이 중간값 필터 방법에 비하여 AAE, AFA가 각각 79.97%~83.64%, 85.62%~87.76% 우수함을 보였다. Since Diffusion tensor from Diffusion Tensor Magnetic Resonance Imaging(DT-MRI) is so sensitive to noise, the principle eigenvector(PEV) calculated from Diffusion tensor could be erroneous. Tractography obtained from PEV could be deviated from the real fiber tract. Therefore regularization process is needed to eliminate noise. In this paper, to reduce noise in DT-MRI measurements, the Dyadic Sorting(DS) method as regularization of the eigenvalue and the eigenvector is applied in the tractography. To resort the eigenvalues and the eignevectors, the DS method uses the intervoxel overlap function which can measure the overlap between eigenvalue-eigenvector pairs in the 3×3 pixel. In this paper, we applied the DS method to the three-dimensional volume. We discuss the error analysis and numerical study to the synthetic and the experimental data. As a result, we have shown that the DS method is more efficient than the median filtering methods as much as 79.97%~83.64%, 85.62%~87.76% in AAE, AFA respectively for the corticospinal tract of the experimental data.
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Median Filter와 Dyadic sorting method를 이용한 DT-MRI Regularization
권순동(Kwon, Soon Dong),우종형,이훈,김태환,권기운,김동윤 한국산업응용수학회 2010 한국산업응용수학회 학술대회 논문집 Vol.5 No.2
자기공명확산텐서영상(Diffusion Tensor Magnetic Resonance Image, DT-MRI)으로부터 얻어진 확산텐서는 확산 타원체로 정의 될 수 있으며, 확산의 비등방성정도와 방향성을 보여주게 된다. 확산이 가장 빠르게 일어나는 방향은 해당 voxel내의 가장 큰 고유값(eigenvalue)에 연결된 고유벡터(eigenvector)의 방향이다. 이러한 PEV(Principle Eigen Vector)는 잡음에 민감하여 정확하지 않은 값을 가질 수 있다. 신경다발추적결과는 이처럼 잡음에 매우 민감한 PEV로부터 얻어지기 때문에 실제 신경다발의 방향에서 벗어날 수 있다. 따라서 잡음을 제거하기 위한 정규화(regularization) 과정이 필요하다. 본 연구에서는 고유값과 고유벡터를 정규화 하기 위한 방법으로 Median Filter과 Dyadic sorting 방법을 사용하였고 이를 구현하기 위한 알고리듬을 제시하였다.
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