연구발표논문초록 ;명반석의 Ammonia 추출잔사로 부터 Alumina제조

조철형,김숭형 한국화학공학회 1974 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.12 No.6

活性炭에 의한 크롬(Cr^(+6)) ion의 吸着〔I〕

조철형,신성의,최형일 조선대학교 생산기술연구소 1983 生産技術硏究 Vol.1983 No.-

The use of domestic activated carbon for removal of the heavy metal was studied by the adsorption characteristics of chromium ion on domestic activated carbon, the adsorption of chromium ion on activated carbon from the effect of pH, velocity of adsorption, isothermal adsorption and removal of chromium ion has been studied. The adsorption characteristic of absorbent used was followed by Freundlich's adsorption isotherm theory, Freundlich constant k, 1/n was 4.5, 0.63 respectively, The adsorption velocity of chromium increased untill zero to 2hr., but after that it was almost come to the equilibrium in an hour. The result showed that removal efficiency of pollution matters was about 70 percent.

연구발표논문초록 : 명반석의 (明礬石) Ammonia 추출잔사로 부터 Alumina 제조

조철형,김숭평 한국화학공학회 1974 추계총회초록집 Vol.- No.-

Atactic Polypropylene의 염소화 반응

조철형,문원,이진대 조선대학교 생산기술연구소 1987 生産技術硏究 Vol.9 No.2

Atactic polypropylene was chlorinated directly In the presence of thionyl chloride all liquid phase to determine the reaction rate equation and its thermal characteristics. The results were as follows; 1) The reaction rate revealed the first order of initial concentration of atactic polypropylene. 2) The degree of chlorination was decreased with increasing the .reaction temperature in the range of 40~80℃. 3) It was elucidated that degree of chlorination was' proportional to the degree of crystallinity of chlorinated polypropylene by thermometry.

고분자 복합재료를 위한 액정중합체(I)

조철형,조성휴,조병욱,김정규,김숭평,권중근 조선대학교 생산기술연구소 1983 生産技術硏究 Vol.1983 No.-

Copolyesters containing oxybenzoate as a rigid rod molecule and methylene group and dimethyl tetramethyl disiloxane as flexible spacers were prepared by room temperature solution polymerization for the purpose of the developement of polymeric composite materials. The thermal properties and the characteristics of the polymers were investigated by DSC and a polarizing microscope. The polymers may be formed nematic liquid crystal phase, and the thermodynamic characteristics of their mesophase to isotropic phase transition could be explained on the basis of its structural features.

Decellularlized Matrix in Organ Transplantation

조철형 한양대학교 의과대학 2014 Hanyang Medical Reviews Vol.34 No.4

Liver transplantation is the only known treatment for patients with end-stage liver failure, but this therapy is limited by the shortage of donor organs. Hepatic tissue engineering combining biomaterial scaffolds and cells have been used as a promising strategy to create engineered liver graft for liver regeneration. Despite significant progress in this field, attempts to create clinically transplantable whole organs have not been as nearly successful. Recently, whole organ decellularization techniques have emerged as a new therapeutic strategy for organ replacement and provided feasibility for clinical translation. The perfusion decellularization method was applied to the whole organ for efficient removal of cellular components and generated organ scaffolds that can maintain the extracellular matrix (ECM) and vascular structure of the native organ. This review paper describes current progress in organ bioengineering for the development of transplantable liver grafts.

Vibrio vulnificus의 세균학적 성상에 관한 고찰

趙哲衡,曺基學 조선대학교 환경연구소 1988 環境公害硏究 Vol.5 No.-

V. Vulnificus has been recognized as a serious pathogen causing life threatening septicemia. Its infection developed after eating raw oyster or raw fish, especially in patients with preexisting liver disease, alcohlism and diabetes mellitus. From January 1988 to December 1987, auther isolate the 28 cases of the V. vulnificus from necrotic skin lesion, bulla fluid and blood of septic patients admitted to the CNUH. The results obtained are as follows. 1. Without certain inhibitory factors, V. vulnificus grew well on common blood agar and classified as Oliver's group Ⅲ by biochemical characteristics. 2. V. vulnificus grew vere poorly without the added NaCl, but grew well on media with 0.25∼6.0% NaCl, especially 1∼3% NaCl, which is same as that of seawater. 3. Range of pH for growht is relatively wide, pH 5.0∼9.0. This organism grew at 20∼42℃ but the optimal temperature for growth was 37℃. Because V. vulnificus did not proliferate but survive at 5℃ or -20℃, it was suggested that this organism could pass the winter. 4. In susceptibiliry test, this organism were susceptibility to most of tested antibiotics except to colistin. These results indicate that person with preexisting severe hepatic dysfunction, heavy alcohlism and certain immunosuppressive states should avoid having raw sea fish and oyster etc. and an early treatment is suitable for V. vulnificus infection.

전 슬관절 치환 성형술에 사용되는 초고분자량 폴리에틸렌 삽입물의 접촉응력에 관한 유한요소해석

조철형,최재봉,최귀원,윤강섭,강승백,Jo, Cheol-Hyeong,Choe, Jae-Bong,Choe, Gwi-Won,Yun, Gang-Seop,Gang, Seung-Baek 대한의용생체공학회 1999 의공학회지 Vol.20 No.1

인공 슬관절에 사용되는 초고분자량 폴리에틸렌(Ultra-high molecular weight polyethylene : UHMWPE)의 마모는 삽입물의 수명을 결정하는 주요 요인으로 작용한다. UHMWPE의 마모로 입자가 발생하여 조직반응을 일으키고 이에 따른 일련의 반응으로 골용해가 일어나 인공관절의 실패의 원인으로 작용한다. 여러 보고들에 의하면 관절 운동시 발생하는 접촉응력은 UHMWPE의 마모에 영향을 미치는 주요한 인자 중 하나로 알려져 있다. 그러나 이러한 보고들은 관절 접촉면에서의 접촉 조건만을 고려했고 UHMWPE 삽입물을 지지하고 있는 금속 지지판과의 접촉면에서의 접촉 조건은 고려하지 않았다. 본 연구에서는 이러한 접촉 조건들을 고려하여 UHMWPE의 모양, 두께, 마찰, 굴곡 정도 그리고 구성 요소들에 대한 UHMWPE 표면과 내부에서의 응력해석을 통해 이들 변수가 UHMWPE의 마모현상에 미치는 영향을 알아보았다. UHMWPE의 모양에 따른 관절의 일치정도(conformity)에 대한 영향의 경우, 일치정도가 높은 모델이 응력을 줄여줄 수 있는 유형으로 나타났으며, 금속 지지판과의 접촉면에서 접촉조건을 준 경우가 완전히 결합된 것으로 가정한 경우보다 UHMWPE 내부에서의 최대 응력이 1-2mm 더 아래에서 나타났다. 또한 UHMWPE로만 된 유형이 금속 지지판이 있는 유형보다 낮은 응력분포를 보여줌으로써 높은 응력으로 인한 UHMWPE의 마모와 균열을 줄이기 위해서는 UHMWPE로만 된 유형의 삽입물의 사용이 좋을 것으로 사료되었다. Because of bone resorption, wear of ultra-high molecular weight polyethylene(UHMWPE) in total knee arthroplasty has been recognized as a major factor in long-term failure of knee implant. The surface damage and the following harmful wear debris of UHMWPE is largely related to contact stress. Most of the previous studies focused on the contact condition only at the articulating surface of UHMWPE. Recently, contact stress at the metal-backing interface has been implicated as one of major factors in UHMWPE wear. Therefore, the purpose of the is study is to investigate the effect of the contact stress for different thickness, conformity friction coefficient, and flexion degree of the UHMWPE component in total knee system, considering the contact conditions at both interfaces. In this study, a two-dimensional non-linear plane strain finite element model was developed. The results showed that the maximum value of von-Mises stress occurred below the articulating surface and the contact stress was lower for the more conforming models. All-polyethylene component showed lower stress distribution than the metal-backed component. With increased friction coefficient on the tibiofemoral contact surface, the maximum shear stress increased about twofold.

동하중상에서 인공무릎관절의 생체역학적인 비교 연구 ( A Biomechanical Study on the Tibial Components Under Dynamic Loding )

조철형,조용균,최재봉,최귀원,이태수 대한기계학회 1998 대한기계학회 춘추학술대회 Vol.- No.-

방향족 액정중합체의 합성 및 액정성

조철형,조병욱,박기주,김선일,최재곤,방문수,이봉우 조선대학교 생산기술연구소 1990 生産技術硏究 Vol.12 No.1

Copolysters were prepared from hydroquinone, 4,4'-biphenol isophthalic acid and bis (P-carboxyphenoxymethyl)disiloxane, and from hydroquinone, terephthalic acid and isophthalic acid. The structures of copolyesters are as follows: ◁화학식 삽입▷ (원문을 참조하세요) The copolyesters obtained were characterized IR and NMR spectroscopy, solution viscosity measurrnents, differential scanning calorimetry (DSC) and X-ray diffractometry. Formation of mesophase and thermal behavior also were studied on a hot stage attached to a polarizing microscope. In case of the copolyesters I, II, copolyesters containing less than 50 mole % IPA, with the exception of the copolyesters I(X=0.4), formed enantiotropic nematic phase. DSC and TGA studies revealed that the thermal stability of copolyesters I was poorer than that of copolyesters II.