GFRP적층판의 설계허용치에 관한 연구

국중석 대불대학교 2003 論文集 Vol.9 No.1

Composite materials were used as structural components because they have better stiffness ratio and strength ratio than metallic materials have. However the heterogeneity and voids of composite materials bring the variation of strength design data. The purpose of this study is to obtain design allowable strengths of GFRP Laminates with 95% trustworthiness. A statistical B-basis method was used to have such data.

치면세균막에서 분리한 뮤탄스 연쇄상구균 및 Streptococcus anginosus의 수종 항생제에 대한 감수성 조사

국중기,임상수,유소영,황호길 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.5

The aim of this study was to investigate the susceptibility of mutans streptococci (S. mutans and S. sobrinus) and Streptococcus anginosus, for seven antibiotics, penicillin G, amoxicillin, ciprofloxacin, cefuroxime, erythromycin, bacitracin, and vancomycin. The minimum inhibitory concentration (MIC) of seven antibiotics against 3 species (type strains) of mutans streptococci and S. anginosus, 10 strains (wild type) of S. mutans, 7 strains (wild type) of S. sobrinus, and 11 strains (wild type) of S. anginosus, were measured by broth dilution method. All of the type strains of mutans streptococci and S. anginosus had the same susceptibility for penicillin G, amoxicillin, cefuroxime and bacitracin. Type strain of S. anginosus was sensitive in ciprofloxacin, but those of mutans streptococci were not. All of the clinical isolates of mutans streptococci and S. anginosus had the same susceptibility for the seven antibiotics. Our data reveal that mutans streptococci and S. anginosus have similar antibiotic-resistant character. In addition. these results may offer the basic data to verify the antibiotic-resistant mechanism of mutans streptococci and S. anginosus.

우리나라 油菜油의 脂肪酸組成에 關한 營養學的 考察

鞠重烈 군산대학교 1979 群山水産專門大學 硏究報告 Vol.13 No.3

Rape seed is getting more important as a raw material according to the increase of demand with oil processing of food in Korea. Racentely, about 30,000 tons of rape seed have produced. But it is considered that there are problems of usage for food, because rape seed oil contains a harmful fatty acid. Therefore, the improvement of fatty acid composition in the oil was necessary for food usage. Accordingly, the improvement of low or zero-erucic cultivars was developed by research workers. But, how is the quality of rape seed oil produced in our country in 1979? In this paper, the chemical and physical properties of rape seed oil were experimented and their fatty acid composition was analized to investigate the quality. With above experiment data nutritional potentiality was considerated also. Samples used for this experiment were collected from six cultivating districts in Korea. But their cultivars were not confirmed. The results were summerized as follows : 1) Specific gravity, refractive index, acid value, iodine value, saponification value and unsaponi-fiable matter were mostly similar to the notice No, 8 of Korean Ministry of Health and Society. 2) The fatty acids composed mainly of 43.95-52.52% of erucic acid, 16.85-19.76% of linolenic acid, 12. 20-17.41% of oleic acid and 13.89-16.79% of linoleic. In addition small quantity of stearic acid and trace amount of others. 3) The rape seed oil contained a great quantity of erucic acid which leads to physiological harm and linolenic acid which is easy to cause rencidity. Therefore it was considered that the rape seed oil was unsuitable for food usage. 4) Because the oil contains a small quantity of oleic acid which is good for cooking and linoleic acid which has an effect on diminution of cholesterol in blood, it was supposed that the rape seed oil is not of excellent quality for food. 5) It was considered that the dissemination of a good cultivar of zero-eruci acid has thoroughly to be promoted to farmers and before usage of food for the present the fatty acid composition must be analized.

복합재 레저 보트의 구조설계 및 해석

국중석 대불대학교 2002 大佛大學校大學院 硏究論文集 Vol.- No.1

Marine leisure industry will be developed remarkably with the improvement of our life level in the 21th century. Currently the design technology of a leisure boat is applied with the one of a fishing ship in our country. The objective of this study is to accomplish structural design and analyses with the method of a advanced foreign company leisure boat.

FRP 선박의 성형공정 개발

국중석 대불대학교 1999 論文集 Vol.5 No.1

At the present, a hand lay-up method in FRP(Fiber Reinforced Plastics) boat manufacture induces both strength reduction and weight gain. Those cause low efficiency of the boat. In this paper, a vacuum bag curing method is presented both to improve the strength and to reduce the weight. The specimen made by the vacuum bag method is weighed and tested with tension. The results of the specimen are compared with the ones of the specimen made by the hand lay-up method.

항공기용 복합재 조종면 개발

국중석 대불대학교 1997 論文集 Vol.3 No.1

Composite material has good specific strength and specific stiffness compared with metal material. So, especially in aerospace division, to acquire the technology about composite structure development is necessary. The objective of this study was to develop the composite control surface of an 8-passengers twin engine aircraft. Preliminary design, structure analysis, detail design, full-scale structural test were accomplished. In load analysis, balance, maneuver and gust load condition were considered. The control surface consisted of C-shape spar, upper and lower skin, full-depth honeycomb and closing rib. The structural test was performed as the stage of preload, limit load, ultimate load and failure load. The results of FEM analysis were almost good agreement with the ones of the structural test. Stability and validity of the structure was proved that the failure load was 925 lb as 1.7 times as the limit load.

소아의 치면세균막에 존재하는 mutans streptococci의 분포

국중기,박종휘,유소영,김화숙,이난영 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.3

한국인 소아의 치면세균막에 존재하는 mutans streptococci 종 및 생물형의 발현빈도와 치아우식경험지수와 상관관계를 알아보기 위하여. 조선대학교 치과병원에 내원한 12세 미만 113명의 소아 환자의 치아우식경험지수를 구하고, 이들의 상하악 유전치 및 유구치의 협면 및 설면의 치면세균막 샘플을 채취하여 mutans streptococci를 mitis-salivarius bacitracin 배지에서 선택적으로 분리하였다. 이들의 biotype을 알아보기 위해 생화학적 검사를 실하였고, 이들의 종 수준에서의 동정을 위해 dextranase 유전자를 표적으로 하는 중합효소연쇄반응을 시행하여 하였다. 113명의 환자 중에서 40명의 치면세균막에서 40 균주의 mutans streptococci이 검출되었다. 이들 중 생물형 제 Ⅰ형 (45%)이 가장 많이 검출되었으며, 그 다음으로 제Ⅳ형 (32.5%), 제 Ⅱ형 (15%). 제 Ⅴ형 (5%), 제 Ⅲ형 (2.5%) 순으로 검출되었다. 또한, 종 수준에서의 발현빈도를 알아본 결과 S. mutans가 69%, S. sobrinus는 31%였다. Mutans streptococci 종 또는 생물형에 따른 환자의 치아우식경험지수간의 차이는 없는 것으로 조사되었다(p>0.05). 이상의 결과를 종합할 때, 한국인의 소아의 구강 내에 존재하는 mutans streptococci중 생물형 제 Ⅰ형인 S. mutans가 가장 높은 빈도로 존재하며, 치아우식증이 세균학적 요소만이 아닌 기타 여러원인 요소에 의해 발병되는 다는 여러 연구 결과와 일치함을 알 수 있었다. The aim of this study is to survey the frequency of mutans streptococci species and biotypes isolated from dental plaque in Korean children and the relationship between species and biotypes of mutans streptococci and dft index. Dental plaques were collected from the anterior and molar teeth of upper and lower jaws in the subjects, aged below 12 years old. A dental examination was performed for dft (decayed, filed, total) with the WHO caries diagnostic criteria. The mutans streptococci from the sample were cultured selectively on mitis salivarius-bacitracine (MSB) agar plate. For biotyping of mutans streptococci, biochemical test was performed. From the culture, bacterial genomic DNA was prepared f3r using of PCR template for the identification of mutans streptococci at the species-level. Forty strains of mutans streptococci were isolated from dental plagues of 40 patients. The biotype Ⅰ (45%) and biotype Ⅳ (32.5%) were most frequently detected. The prevalence of s. mutans and S. sobrinus was 69% and 31%, respectively There was no positive relationship between species and biotypes of mutans streptococci and dft index. Our results revealed that biotype Ⅰ and S. mutans were frequently detected in Korean children and support that dental caries incidents by many causative factors not only bacterial factor.

Bifidobacterium angulatum으로부터 α-galactosidase의 정제 및 특성

강대중,민해기,강국희 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.1

α-galactosidase는 (α-D-galactoside galactohydrolase: EC 3.2.1.22)는 다당류나 올리고당인 melibiose, raffinose, stachyose와 guar gum 등의 α-galactosidic 결합을 하고 있는 당을 분해하는 효소이다. 장내세균중 우익균이며 우세균주인 Bifidobacteria로부터 α-galactosidase의 효소학적 특성을 알아보기 위하여 배양여액으로부터 ammonium sulfate분획, 핵산의 제거, Sephadex G-200 gel filtration 및 DEAE-Sephadex A-50 ion exchange chromatography 등의 4단계 정제과정을 거쳐 정제한 결과 약 8배로 정제되어 단일 단백질로 분리하였다. 또한, 효소분해산물을 알아보기 위하여 TLC에 의하여 당분해 및 올리고당의 생성을 알아보았다. 정제효소의 활성 최적온도는 37℃, 최적 pH는 7.0이었다. 효소활성이 K^+, Zn^2+과 같은 금속이온과 8-Hydroxyquinoline, Sodium Bisulfite 등에 의해선 그다지 저해되지 않았으나, Hg^+, Cu^2+과 p-Chloromercuribenzoic acid에 의해선 저해되었다. 효소의 분자량이 301, 995, 합성기질인 PNPG에 대한 K_m은 0.069mM, V_max는 347.22μmol/min.mg protein이었다. To elucidate enzymatic properties of α-galactosidase (EC 3.2.1.22) from Bif.angulatum. α-galactosidase was purified to homogeneity by ammonium sulfate fractionation, protamine sulfate precipitation, sephadex G-200 gel filtration, and DEAE-sephadex A-50 ion exchange chromatography. The purified α-galactosidase was found tobbe homogeneous by SDSpolyacrylamide gel electrophoresis. The molecular weight of this enzyme, estimated by sepadex G-200 gel filtration, was about 301,995. The optimum conditions for the enzyme reaction was pH 6.5 to 7.0 at 37℃. The purified enzyme was stable at 45℃ or below and in buffer at pH 6 to 7.0. The activity was inhibited by mercury, copper ion, and p-chloromercuribenzoic acid. The kinetics of this enzyme, with p-nitrophenyl-α-D-galactoside as substrate, was determined : K_m was about 0.069mM and V_mas was 347.22 μmoles/min mg protein.

Penicillium sp.에 依한 α-Galactosidase 生成에 關한 硏究

金鍾國,朴啓仁,愼重燁 경희대학교 부설 식량자원개발연구소 1984 硏究論文集 Vol.5 No.-

The strong α-Galactosidase producing micro-organism was isolated from soil of soybean field and identified as Penicillium janthinellum. The optimum cultural and enzyme condition of P. janthinellum were investigated. The cell growth and enzyme production of P. janthinellum were observed to reach maximum at pH 5.0 in xylose medium and α-Galactosidase of P. janthinellum was produced constitutively. The optimum pH of crude α-Galactosidase was pH 5.0. The optimum temperature of crude α-Galactosidase was 50℃ and the enzyme was inactivated completely at 70℃ in 10 min.

Penicillium sp.에 依한 α-Galactosidase 生成에 關한 硏究

金鍾國,朴啓仁,愼重燁 慶熙大學校 1984 論文集 Vol.13 No.-

The strong α-Galactosidase producing micro-organism was isolated from soil of soybean field and identified as Penicillium janthinellum. The optimum cultural and enzyme condition of P. janthinellum were investigated. The cell growth and enzyme production of P. janthinellum were observed to reach maximum at pH 5.0 in xylose medium and α-Galactosidase of P. janthinellum was produced constitutively. The optimum pH of crude α-Galactosidase was pH 5.0 The optimum temperature of crude α-Galactosidase was 50℃ and the enzyme was inactivated completely at 70℃ in 10 min.