판상형 충전제의 함량과 배향에 따른 PP복합체의 열팽창계수 영향 연구

이기윤(Kee Yoon Lee),이용현(Yong Hyun Lee),정선경(Sun Kyoung Jeoung),황효연(Hyo Yeon Hwang),이승구(Seung Goo Lee) 한국고분자학회 2012 폴리머 Vol.36 No.3

두 가지의 종횡비(ρα=a1/a3 and ρβ=a1/a2)에 의해 특징지어진 3차원 타원체(a1 > a2 > a3)를 사용하여 polypropylene 복합체의 판상형 충전제 함량과 방향이 열팽창률에 미치는 영향에 대해 실험적인 연구를 수행하였다. 측정된 실험적인 값은 Lee와 그의 연구자들이 제안한 이론적인 모델에 의한 계산 값과 비교분석되었다. 판상형충전제로는 운모와 탈크가 사용되었다. 실험 결과로 운모의 경우 종횡비는 ρα= 13.5, ρβ= 1.8이 사용되 어, 20 wt% 함량일때 α11/αm는 약 0.56으로 감소하였으나, α33/αm는 오히려 1.018로 증가함을 보였다. 탈크의 경우의 종횡비는 ρα=3.7, ρβ= 1.4이었고 α11/αm는 0.63으로 감소하였다. 결국 운모와 탈크 모두 그 함량증가에 따라 종단방향과 횡단방향에서 열팽창률은 감소하였으나 수직방향에서는 초기 낮은 충전제 함량에서는 오히려 증가하는 경향을 보였다. Experimental study was performed regarding the effects of disc-like filler orientation and contents on the coefficient of thermal expansion (CTE) of polypropylene composites using the three dimensional ellipsoids (a1 > a2 > a3) analyzed by two aspect ratios(ρα=a1/a3 and ρβ=a1/a2). Measured data were compared with the theoretical approaches proposed by Lee et al. Mica and talc were useed as disk-like fillers in the composites. As experimental results, α11/αm decreased down to ca. 0.56 with mica content of 20 wt% and the aspect ratios, ρα=13.5, ρβ=1.8. However, α33/αm increased to more than 1. In the case of talc, α11/αm decreased to ca. 0.63 with 20 wt% and ρα=3.7, ρβ=1.4. Finally, the longitudinal CTEs (α11) of polypropylene composites decreased as filler contents increased, but normal CTE (α33) increased in the low filler contents like the theory.

Comparison of Melanoma Subtypes among Korean Patients by Morphologic Features and Ultraviolet Exposure

( Hong Sun Jang ),( Jee Hung Kim ),( Kyu Hyun Park ),( Jae Seok Lee ),( Jung Min Bae ),( Byung Ho Oh ),( Sun Young Rha ),( Mi Ryung Roh ),( Kee Yang Chung ) 대한피부과학회 2014 Annals of Dermatology Vol.26 No.4

Background: Genetic alterations have been identified in melanomas according to different levels of sun exposure. Whereas the conventional morphology-based classification provides a clue for tumor growth and prognosis, the new classification by genetic alterations offers a basis for targeted therapy. Objective: The purpose of this study is to demonstrate the biological behavior of melanoma subtypes and compare the two classifications in the Korean population. Methods: A retrospective chart review was performed on patients found to have malignant melanoma in Severance Hospital from 2005 to 2012. Age, sex, location of the tumor, histologic subtype, tumor depth, ulceration, lymph node invasion, visceral organ metastasis, and overall survival were evaluated. Results: Of the 206 cases, the most common type was acral melanoma (n=94, 45.6%), followed by nonchronic sun damage-induced melanoma (n=43, 20.9%), and mucosal melanoma (n=40, 19.4%). Twenty-one patients (10.2%) had the chronic sun-damaged type, whereas eight patients (3.9%) had tumors of unknown primary origin. Lentigo maligna melanoma was newly classified as the chronic sun-damaged type, and acral lentiginous melanoma as the acral type. More than half of the superficial spreading melanomas were newly grouped as nonchronic sun-damaged melanomas, whereas nodular melanoma was rather evenly distributed. Conclusion: The distribution of melanomas was largely similar in both the morphology-based and sun exposure-based classifications, and in both classifications, mucosal melanoma had the worst 5-year survival owing to its tumor thickness and advanced stage at the time of diagnosis. (Ann Dermatol 26(4) 485~490, 2014)

판상형 충전제의 함량과 배향에 따른 PP복합체의 영률 변화 연구

서상범(Sang Bum Seo),이용현(Yong Hyun Lee),정선경(Sun Kyoung Jeong),이승구(Seung Goo Lee),이기윤(Kee Yoon Lee) 한국고분자학회 2012 폴리머 Vol.36 No.2

이 논문은 판상형 충전제의 함량과 배향에 따라 폴리프로필렌 복합체의 영률 변화에 미치는 영향을 연구 하였다. 이론적인 예측은 Lee와 그의 연구자들에 의해 제안된 두 개의 종횡비, ρα=a1/a3과 ρβ=a1/a2 를 이용하여 3차원 타원체의 형상을 계산하였고 실험값과 비교 분석하였다. 판상형 충전제로 운모와 탈크를 사용하였다. 충전제의 형태는 SEM을 이용해 관찰하였고, 종횡비는 고분자의 흐름을 기준으로 좌표축을 설정하여 통계적 방법으로 계 산하였다. 충전제가 운모인 경우에 ρα=13.5와 ρβ=1.8이었고, 탈크의 경우는 ρα=3.8과 ρβ=1.4이었다. 또한 충전제 의 2개의 종횡비와 함량이 기계적 물성에 미치는 영향을 실험적으로 연구하였다. 운모의 경우 30 wt% 함량일 때 E11이 약 2.7배 향상되었다. 탈크의 경우는 E11이 약 2.3배 향상하였다. This paper studied the effects of the content and the orientation of the disk shape fillers on the modulus of PP composites. The experimental results were compared with the theoretical calculations which included the three dimensional ellipsoids and analyzed by two aspect ratios, ρα=a1/a3 and ρβ=a1/a2 proposed by Lee and his researchers. Mica and talc were used as disk shape fillers in the composites. The shapes of mica and talc were observed by SEM and aspect ratios were statistically calculated. For the case of mica, the average aspect ratios were ρα=13.5 and ρβ=1.8, and for the case of talc, they were ρα=3.8 and ρβ=1.4. Also, the effects of two aspect ratios and the content of filler on the mechanical properties were studied: For 30 wt% of mica, E11 increased up to about 2.7 times, and for the other case of talc, E11 increased up to about 2.3 times, respectively.

여성 외음부에 발생한 선상 편평상피세포암종

김창옥,양기화,강석진,이안희,김병기,김선무 대한병리학회 1991 Journal of Pathology and Translational Medicine Vol.25 No.1

교통사고로 인한 외상 후 스트레스 장애에서 증상 정도에 따른 인지기능의 차이

이재영,기백석,조순동,서동수 한국정신신체의학회 2003 정신신체의학 Vol.11 No.1

8.3% Carbamide Peroxide 함유 펜 형 자가미백제인 BIancTis Forte의 색조개선 및 안전성에 관한 임상연구

이진경,민선홍,홍성태,오소람,정신혜,황영혜,유성엽,배광식,백승호,이우철,손원준,금기연 대한치과보존학회 2009 Restorative Dentistry & Endodontics Vol.34 No.2

This clinical study evaluated the whitening effect and safety of polymer based-pen type BlancTis Forte(NIBEC) containing 8.3% carbamide peroxide. Twenty volunteers used the BlancTis Forte whitening agent for 2 hours twice a day for 4 weeks As a control. Whitening Effect Pen (LG) containing 3% hydrogen peroxide was used by 20 volunteers using the same protocol. The change in shade (ΔE^(*) color difference) was measured using Shadepilot™ (DeguDent) before, during and after bleaching (2 weeks, 4 weeks and postbleaching 4 weeks). A clinical examination for any side effects (tooth hypersensitivity or soft tissue complications) was also performed at each check-up. The following results were obtained. 1 Both the experimental and control groups displayed a noticeable change in shade (ΔE) of over 2 No significant differences were found between the two group (p>0.05) implying that the two agents have a similar whitening effect. 2 The whitening effect was mainly due to changes in a and b values rather than in L value (brightness). The experimental group showed a significantly higher change in b value thus yellow shade than the control(p < 0.05) 3 None of the participants complained of tooth hypersensitivity or soft tissue complications confirming the safety of both whitening agents 8.3%의 carbamide peroxide를 함유한 펜형 코팅용 미백제인 BlancTis Forte (NIBEC, Seosul & JinCheon)를 실험군으로, 3% hydrogen peroxide를 함유한글 Whitening Effect Pen (LG. Seoul) 제재를 대조군으로 각각 피험자 20명에게 2시간씩 1일 2회 제조사의 지시대로 치아표면에 4주간 적용하도록 지시하고 색조개선 효능과 안전성을 평가하였다. 미백 효과는 미백 전 및 미백 2주, 4주 및 미백 종료 4주 후에 Shadopilot™을 이용하여 색 변화를 측정하였고, 매 내원시기마다 모든 환자는 치수생활력 검사와 치주 및 치태 검사를 통해 부작용 여부 (치아과민증 및 구감 내 연조직의 부작용)를 기록한 후 다음과 같은 결과를 얻었다. 1.실험군 및 대조군의 색 변화량 (ΔE)은 2이상으로 인지할 수 있는 색 변화를 보였으며, 두 제품 간에는 통계적으로 유의한 차이를 보이지 않아 (p > 0.05) 유사한 미백효능을 나타냄을 알 수 있었다. 2,미백효과는 명도의 개선보다는 주로 a. b값의 변화에 의한 것으로 특히 실험군에서 b값의 변화, 즉 황색조의 개선효과가 대조군에 비해 유의성 있게 높은 것으로 나타났다 (p <0.05). 3.치아나 치은의 과민증이나 이상증상을 호소하는 피험자는 없어 두 제품 모두 안전성을 확인할 수 있었다.

키르리안 카메라로 기(氣)사진을 찍을 수 있는가 ?

이기방,이선정 全北大學校 科學敎育硏究所 1999 과학과 과학교육 논문지 Vol.24 No.-

The Qi of universe and body has been examined in terms of modern physics and the Oriental philosophy. The meridian theory of the Oriental medicine was interpreted based on the bio-oscillation of body cells under an assumption that the Qi is a unique oscillatory phenomenon of universal quantum field with eigen-frequencies and can not be seen by naked eyes. It is shown that the 20 meridians in human body are the path ways of the metabolic effete matters and the informational net-work controlling the activities and the functions of all the organs. We suggest here to read Qi from the aura photos of a body taken by a Kirlian camera.

재무제표 구조 개선에 관한 연구 : 국제비교 중심으로

이대선,고완석,유청을,송기신,박성환 서강대학교 경영학연구원 2002 서강경영논총 Vol.13 No.1

조직시민행동에 관한 이론적 고찰 : 고용형태와 개인특성, 직무특성의 영향을 중심으로

이영면,한기선 동국대학교 경제경영연구원 2001 經濟經營硏究 Vol.25 No.1

The objective of this study is to investigate the difference of Organizational Citizenship Behavior between regular position and irregular position. Hence, our study is to analyze theoretically the relationship of activated increase of irregular position and organizational citizen behavior from a part of reducing the labor cost in the corporate's structural regulation. As a result, confronting IMF economic crisis, banks couldn't survive and vanished. So to maintain their existence, many banks is remodeling organization and correcting employment and introducing new management innovation techniques, which is very important and no wonder to do that. But we can find that individual bank is controling their employment intending to reduce labor cost. Of course in the environment of keen competition there is no other choice. However, we must examine throughly that reducing labor cast for a short term can follow for banks to strengthen the competitiveness in the long view.

질화 분위기에서 결정화 된 Fe_(73.5)Si_(13.5)B_(9)Cu₁Nb₃ 연자성 합금의 자기적 성질

이기선,박인수,이기안,김문철,장석훈 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.11

Amorphous Fe_(73.5)Si_(13.5)B_(9)Cu₁Nb₃ alloy was crystallized in nitriding atmosphere of mixture gas of NH₃ and hydrogen. The crystallization at 823K showed the high electrical resistivity ranging from 494 to 538 mW-cm, which was higher level compared with nano-crystalline Fe_(73.5)Si_(13.5)B_(9)Cu₁Nb₃ alloy with a resistivity of about 110 mW-cm. Through the nitridation treatments, the amorphous alloy was transformed into nano-sized crystalline Fe3Si including iron nitrides such as γ' -Fe₄N phases. EPMA-concentration depth profiles confirmed an existence of nitrogen-rich region on the surface of the alloy ribbon, leading to the preferential formation of g -Fe4N phase. The formation of γ' -Fe₄N phase leaded to an increase of the resistivity and provided stable permeability and a low core loss at high frequency.