PMMA와 SAN混合物의 劣化速度에 관한 硏究

薛秀德,韓丞完,金東建,文德柱 동아대학교 공과대학 부설 한국자원개발연구소 1988 硏究報告 Vol.12 No.2

The thermal degradation behavior of the homopolymer poly(methyl methacrylate) (PMMA) and styrene-co-acrylonitril (SAN) as well as their mixture were carried out using the thermogravimetric and infrared spectroscopy method in the stream of various gases. The activation energies evaluated by the reported various kinetics equations except PMMA80%-SAN20% Mixture agreed with each other very well. The thermal degradation of PMMA and SAN mixture were considered to be carried out by the main chain scission.

半夏의 修治方法에 따른 細胞毒性硏究

李秀培,金德宗,金康柱,田炳勳,禹元洪 圓光大學校 韓醫學硏究所 1993 원광한의학 Vol.3 No.1

The purpose of this study is to know the effects of Pinelliae Tuber on the cytotoxicity of human gingival fibroblasts according to brewing methods. Pinelliae Tuber was extracted by water in the state of being raw materials, prebrewing with Zingiberis Tuber and alumen. The extracted Pinelliae Tuber was applied to the cultured human gingival fibroblasts. The cytotoxic effct of Pinelliae Tuber was meaeured by MTTassay and microscopic findings. The results were as follows : 1. The cell viability of the fibroblasts by Pinelliae Tuber water extracts significantly decreased compared to control group. 2. The cell viability by the Pinelliae Tuber extracts prebrewed with Zingiberis Tuber was similiar to those of control group. 3. The cell viability by the Pinelliae Tuber extracts prebrewed with alumen slightly decreased, but was higher than those of PT group. 4. According to the microscopec findings, the number of cell count were smaller than normal in all experimental group, specially in the PT group, and showed the shrinkage of cytoplasmic process in the PT group and PA group.

도금사업장의 작업환경의 유해인자 노출수준에 관한 연구

문덕환,도수영,이채관,황용식,선병관,손병철,김대환,이창희,김휘동,이채언 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.5

Objective : For the purpose of preparing the fundamental data and assessing the status of exposure level of chemical substances and physical agents. Methods and Material : Such as noise, two types of dust, four types of metals, seventeen types of organic solvents, and four types of other materials classified by specific chemical substances in 21 metal product plating factories classified by 28 processes. The author determined exposure level on those hazardous materials from Jan. to Dec. 2001. Results : The results were as follows: 1. The exposure level for noise was exceeded to Threshold Limit Value(TLV) in the process of 6 cases of Machining, 5 and 4 cases of pre and post-buffing, and 6 cases of waterdrop-removing, the mean noise level of all of processes was not exceeded to compliance level. 2. The exposure level for dust was not exceeded to TLV at all. 3. The exposure level for Chromium(Cr) was exceeded to TLV in Chromium plating process, metal exposure level including Zinc(Zn), Manganese(Mn), and Lead(Pb) was not exceeded to TLV. 4. The exposure level of toluene in case of organic solvents was exceeded to TLV in 1 case of finishing/cleaning, coating/developing process, respectively. 5. The exposure level of four types of other materials classified by specific chemical substances were not exceeded to TLV. 6. The exposure level for dust and metal including Zn, Mn, and Pb was decreased in comparison with two results of air monitoring performed. There was no difference of the exposure level for Cr, noise, and four types of other materials classified by specific chemical substances, and the exposure level for organic solvents was slightly increased. 7. The exposure level for noise in factories employing more than 21 workers was higher than that for noise in foadtories employing less than 20 workers. The more workers, the lower exposure level in metal including Zn, Mn. The exposure level for Cr was increasing in factories employing more than 51 workers, and the more workers the lower exposure level in organic solvents. Conclusion : According to above results, this study suggests positive work environment managements in processes exceeding exposure limit value as well as continuously consecutive work environment management in processes not exceeding exposure limit value and revealing no chronological difference of exposure level should be needed.

Imide 단위를 포함하는 Polyamide의 합성과 열적 성질

길덕수,배장순,공명선 단국대학교 신소재기술연구소 1997 신소재 Vol.7 No.-

Imide 단위를 포함하는 diamine과 dicarboxylic acid 단량체들, N-(4-aminophenyl)-4-aminophthalimide(1), N-(4-carboxyphenyl)-4-carboxyphthalimide(2), N,N'-oxydiphenylenebis(4-aminophthalimide)(3) 및 N,N'-oxydiphenylenebis(4-carboxyphthalimide)(4)를 합성하였다. 위의 단량체들은 서로 축합하여 imide 단위가 교대된 poly(imide-amide)s를 합성하였으며 imide 단위를 포함하는 diamine 단량체들은 terephthaloyl chloride, isphthaloyl chloride와 축합하여 또다른 poly(imideamide)s를 합성하였다. 이렇게 합성된 중합체들은 NMP/LiCl 용액에 매우 잘 용해하였으나 그밖에 극성 반양자성 용매인 DMF, DMSO 및 DMAc 등에는 낮은 용해도를 보여주었다. 고유 점성도는 0.15-0.51 dL/g 이었으며 NMP/LiCl 용액으로부터 단단하지만 취성이 있는 고체막이 형성되었다. 중합체들의 유리전이온도 및 융점은 관찰되지 않았으나 400℃ 부근에서 서서히 분해가 시작되었으며, 중합체들은 500℃에서 82-93%의 잔사량을 나타내어 우수한 열적성질을 보여주었다. Diamine and dicarboxylic monomers with imide linkage, N-(4-aminophenyl)-4-aminophthalimide(1), N-(4-carboxyphenyl)-4-carboxyphthalimide (2), N,N'-oxydiphenylenebis (4-aminophthalimide)(3) and N,N'-oxydiphenylenebis (4-carboxyphthalimide) (4) were prepared, and poly(amide-imide)s with ease processing characteristics were prepared from the monomers, 1-4 and terephthaloyl chloride or isophthaloyl chloride. Intrinsic viscosity of polymers was 0.15-0.51 dL/g and brittle hare films were obtained by casting the NMP/LiCl polymer solution on to glass plate. The poly (amide-imide)s are easily solubiel in NMP/LiCl and also in polar aprotic solvents such as DMF, DMSO, NMP and DMAc at 80℃. These polymers showed no glass transition temperature and melting temperature in their DSC thermograms. All the polymers decomposed at around 400℃ and 500℃ in nitrogen and had 88∼93% residual weight at 500℃.

콘크리트-폴리머 복합재료 개발(Ⅱ) : Physical Properties of Polymer(Resin) Concrete 폴리머(레진) 콘크리트의 물성

황의환,길덕수,황택성 공주대학교 자원재활용 신소재 연구센터 1999 1차년도 센터 성과집 Vol.1999 No.-

고기능성 건설재료로 활용하기 위하여 불포화폴리에스테르수지를 사용한 폴리머 콘크리트의 물성에 대하여 조사하였다. 탄산칼슘(충전제)의 첨가량(5~20 wt %)과 세골재의 첨가량(10~50 wt %)에 따라 다양한 공시체를 제작하여 압축 및 휨강도, 흡수시험, 내열수성시험, 내산성시험, 세공분포측정 및 SEM에 의한 미세조직 관찰등을 실시하였다. 그 결과 폴리머 콘크리트의 압축강도와 휨강도는 시멘트 콘크리트보다 4배 정도 향상되었고 흡수율은 1/100로 가소되었으며, 내산성시험에 의한 중량감소율은 1/27로 현저히 감소되었다. 내열수성시험후에 측정한 폴리머 콘크리트의 압축 및 휨강도는 모두 내열수성시험전에 측정한 강도에 비하여 67%, 47%로 각각 감소되었으며 폴리머결합체의 분해에 의하여 세공율은 크게 증가되었다. The phsical properties of polymer concrete were investigated for development of high performance construction materials. Various specimens of polymer concrete were prepared using unsaturated polyester resin as the ploymer binder with the various dosge of clcium carbonate as microfiller (5~20 wt %) and fine aggregate(10-50%). For the evaluation of the physical properties of polymer concretes, tests such as compressive strength, flexural stength, water absorption test, hot water immersion test, acid resistance test and pore size distribution analysis were conducted. As a result, it is concouded that compressive and flexural strengths of ployemr concretes increased up to 4times than those of conventional cement concrete. Whereas the compressive and flexural strengths of polymer concretes tested after hot water immersion, compared volume and porosity(%) of polymer concretes were remarkably increased due to decomposition of polymer binder. And also, it is showed that water absorption(%) and weight loss(%) of polymer concrete specimens by acid immersion, compared with those of ordinary portland cement cocrete decreased about 1/100, 1/27, respectively.

고분자에 고정된 유기주석 촉매의 합성

徐延穆,吉德洙,孟學永 公州大學校 基礎科學硏究所 1994 自然科學硏究 Vol.3 No.-

공중합체 내의 염소 성분의 함량 변화는 methylal을 용매로 사용하였을때 3% 가교도의 공중합체가 최대이었으며 그 이상의 가교도를 지닌 공중합체에서는 거의 동일하였다. 팽윤율은 Methylal 용매중에서 3% 가교화 ST-DVB 공중합체가 최대로 팽윤되었으며 그 이상의 가교도를 지닌 공중합체에서는 자동가교의 영향으로 인하여 거의 일정하였다. ST-DVB 공중합체의 다공도 변화는 가교도가 5%일때 최대였으며 그 이상에서 거의 일정하였다. Crosslinked ST-DVB Copolymer was Chloromethylated, vinylated, and orgnometalated. When degree of crosslinkage was 3%, the chlorine content and the degree of swel ling of the polymer was highest in methylal solvent. The pore volme is highest in 5%-crosselinked polymer.

폐FRP 미분말을 재활용한 PAE 폴리머 모르타르의 물리적 특성

황의환,길덕수,노재성,이병기 공주대학교 자원재활용 신소재 연구센터 2002 센터사업 성과집 Vol.- No.1

In order to recycle the FRP wastes from SMC bathtubes, polymer-modified mortars containing a fine powder of fiber-rainforced plastics(FRP) as a part of the sand were prepared with various FRP replacements for sand and polymer cement rations. The polymer modifier used was polyacrylic ester(PAE) emulsion. The FRP waste fine powder was obtained by pulverizing FRP wastes. The water-cement ratio, compressive and flexural strength, water absorption and hot water immersion of the mortar were tested and the results compared to those of ordinary cement mortal and polymer-cement mortal. As the results, compressive and flexural strengths of ordinary portland cement mortars containing FRP wastes fine powder were remarkably decreased with an increase of a content of FRP wastes fine powder. But those strengths of ordinary portland cement mortars were greatly improved by adding PAE emulsion. When the replacement ratios of FRP wastes fine powder and adding rations of PAE emulsion were 5, 10, 20wt% and fine powder were showed as much those strengths of ordinary portland cement mortar. Otherwise heat curing of PAE-modified mortar containing FRP wastes fine powder accelerated the improvement of early compressive and flexural strengths. But the compressive and flexural strengths of PAE-modified mortar containing FRP wastes fine powder were remarkably decreased after hot water immersion test.

生分解性 共重合體의 重合 및 物性에 관한 硏究(I)

崔乘載,吉德洙,趙壬元 단국대학교 1995 論文集 Vol.29 No.-

The graft ploymerization of methyl methacrylate onto starch initiated by ceric ammonium nitrate. The grafted polymer was identified by using IR spectroscopy. Four copolymer samples with grafting percents of 34.29%, 48.71%, 57.89% and 67.89% were tested for their microbial susceptibility in a synthetic medium employing a inoculum of aspergillus niger, trichoderma viride. Starch-g-poly(methyl methacrylate)copolymer films show excellent susceptibility to fungal growth, some samples losing more than 14% of their weight after 15days of incubation with aspergillus niger. There was initial rapid weight loss accompanied by the exponential increase in bacterial population and pH of the culture medium during the second week. The extent of degradation seems to decress with increasing grafting percent.

혈관중심성 T세포/자연살상세포 림프종의 임상적 고찰

이정찬,박수진,박상은,곽승근,신현영,김성은,이정호,윤환중,조덕연,김삼용 충남대학교 의과대학 지역사회의학연구소 2001 충남의대잡지 Vol.28 No.1

Although the Working Formulation is commonly used to classify NHL in Korea, it has been recognized as imperfect for primary extranodal lymphoma, expecially for patients with nasal, paranasal disease because of their histological characteristics. Angiocentric T/NK cell lymphoma remains rare clinical presentation in North America and Europe but is more common in Asia and Latin America. The optimal mode of treatment has also not been decided on, probably because of their rarity and limited understanding of its natural course. The aim of this study was to analyze our experience with 14 patients with angiocentric lymphoma seen at the Chungnam Natioanl University Hospital over the last 5 years. We reviewed the records of 14 patients who were treated at the Chungnam National University Hospital between January, 1996 and December, 2000. The angiocentric T/NK cell lymphoma accounted for about 8.2% of NHL. The median age was 52.5 (range 36-71) years. Sex ratio was equal. According to the Ann Arbor staging system, disease was classified as stage Ⅰin 3 patients, stage Ⅱ in 8 patients and stage Ⅳ in 3 patients. Systemic B symptoms were present in only four patients in only four patients. All patients has extranodal involvement. The most frequently involved extranodal sites were nasal cavity followed by paranasal sinuses and orpharynx. The most common presenting symptoms were nasal obstruction with purupent rhinorrhea followed by dysphagia. According to the International prognostic index (IPI), most patients was in low-risk group (11 patients). Nine patients responded completely. Seven patients were received combination chemotherapy and 2 patients had radiation therapy as a initial treatment. Five patients were relapsed. After a median follow-up of 660.5 days, the overall survival and disease-free survival rates at 3 years was 56.8% and 42.9% respectively. The median survival time was not yet reached. The median overall survival time was 1338.5 (range 1212-1564) days for non-relapsed and 733.4 (range 302-1008) days for relapsed patients. The median time from CR to relapse was 100.5 (range, 39-159) days. There were limitations to know enough about the characteristics of angiocentric T/NK cell lymphoma because of a small number of patients. In the future, multicenter trials will be neccesary to identify clinical characteristics, optimal treatment mordalities and their responses, and prognostic factors.

Methylphenidate 투약에 따른 주의력결핍 과잉운동장애 아동의 정량화 뇌파의 변화

이병대,정성훈,이만기,장수민,백지령,임효덕 대한생물치료정신의학회 2002 생물치료정신의학 Vol.8 No.1