Rheo-compocasting 법으로 제조된 알루미나 입자강화 Al 합금 복합재료의 계면반응

현석종,예병준 ( Suhk Jong Hyun,Byung Joon Ye ) 한국주조공학회 1993 한국주조공학회지 Vol.13 No.3

N/A Aluminum alloy 2024 matrix composites reinforced with Al₂O₃particles, were prepared by rheo-compocasting, a process which consists of the incoporation distribution of reinforcement by stirring within a semi-solid alloy. The microstructures and characteristics of the interfaces have been studied using optical microscope and scanning electon microscope in 2024 aluminum alloy composites reinforced with Al₂O₃particles. The main results are as follows: (1) Al₂O₃particles were well distributed in composites by using rheo-compocasting. (2) As the addition of Al₂O₃particle increases, the average dendrite numbers and the hardness were increased. (3) Interaction between Al₂O₃particles and alloy 2024 resulted in the formation of Mg and Cu element rich region around the Al₂O₃particles.

우리나라에서 분리되는 Haemophilus influenzae의 9종 항균제에 대한 시험관내 감수성

장우현,최명식,석종성,정윤섭,서진태 대한화학요법학회 1989 대한화학요법학회지 Vol.7 No.2

To assess the occurrence of antimicrobial resistance among clinical isolates of H. influenzae in Korea, a total of 238 isolates were tested for their in vitro susceptibitlity to ampicillin and cefaclor by disc diffusion and 105 isolates were tested against nine antimicrobial agents-by the agar dilution method recommended by NCCLS. The antimicrobial agents sued for testing were ampicillin (Sigma A-9518, U.S.S.), cefaclor (Daewoong Lilly, Korea), cephalexin (Sigma C-4895, U.S.A.), cephradine (Sigma C-8395, U.S.A.), cephalothin (Sigma C-4520, U.S.A.), cefadroxil (Sigma C-7020, U.S.A.), erythromycin (Sigma E-6376, U.S.A.), teracycline (Sigma T-3383, U.S.A.) and cefatrizine (Dong-A Pharmaceutical Co., Korea). The isolation rate of H. influenzae from various clinical samples was 18.9%. Using the disc diffusion test, the resisant rates to ampicillin and cefaclor were shown to be 21.9% and 3.4%, respectively. Among the 52 ampicillin-resistant strains, 42 were susceptible to cefaclor (80.8%), and only two strains wre resistant. The MIS_(s) of ampicillin ranged from <0.125 ㎍/㎖ to >128 ㎍/㎖, and its MIC_(90) was 1 ㎍/㎖. Ampicillin showed the lowst MIC_(90) among the tested antivicrobial agents. The MIC_(90) of the tested cephalosporins ranged from 9.2㎍/㎖ to > 128. Among them, cefaclor showed the lowest MIC_(90) and its MIC_(90) was 9.2 ㎍/㎖. The MIC_(90) of tetracycline and erythromycin were 2.5 ㎍/㎖ and 14.4 ㎍/㎖, respectively. By the MIC, the resistant for ampicillin, cefalor, cephalexin, cephracine, cephalothin, cefadroxil, erythromycin, tetracycline and cefatrizine were 9.5%, 1.9%, 61.9%, 76.2%, 3.8%, 68.6%, 65.7%, 13.3% and 5.7%, respectively. There was no evidence that the MIC_(s) of cefaclor for the ampicillin-resistant strains differed significantly from those of cefaclor obtained with the ampicillin-susceptible strains. Except two islates, all of the multiple-esistant strains of H. influenzae were suceptible to cefaclor.

Comparative In Vitro Activities of Ciprofloxacin and Other Nine Antibiotics to Clinical Isolates in Korea

Chang, Woo Hyun,Choi, Myung Sik,Suk, Jong Sung 대한화학요법학회 1987 대한화학요법학회지 Vol.5 No.2

Nalidixic acid 유도체중 최근 개발된 fluorinated quinolone compound의 하나인 ciprofloxacin은 그람양성 및 그람음성균에 대해 모두 효과적인 광범위 항생제로 알려져 있으며 특히 녹농균에 대해 탁월한 항균능을 지닌다고 보고되고 있다. 저자들은 1986년도에 서울대학교병원에서 분리한 총 532균주의 그람양성 및 그람양성균을 대상으로 ciprofloxacin의 항균효과를 검증하고 또한 norfloxacin, amino-glycoside계 항생제, 반합성 penicillin 제재 항생제 및 cephalosporin과의 상대적 항균효과를 비교하여 다음과 같은 결과를 얻었다. 항균효과는 2배 계단희석하여 항생제 농도 범위가 0.0009 ㎍/㎖에서 128 ㎍/㎖되게 하여 최소발육억제농도를 측정 검증하였다. 1. Enterotoxigenic E. coli, uropathogenic E. coli, Serratia spp., S. typhi, P. aeruginosa, C. freundii, E. cloacae, K. oxytoca, K. pernumoniae, P. vulgaris, M.morganii, S. aureus 및 S. epidermidis에 대한 ciprofloxacin의 MIC90은 0.1 ㎍/㎖ 이하였으며 Alcaligenes spp.에 대한 MIC90은 0.14 ㎍/㎖이였고, P. mirabilis에 대해서는 3.10 ㎍/㎖이었다. 2. Ciprofloxacin은 norfloxacin, aminoglycoside계 항생제, 반합성 penicillin 제재 및 cephalosporin계 항생제재에 비해 그람음성장내세균, N. gonorrheae 및 그람양성구균에 대해 높은 항균능을 나타내고 있었다. This study was designed to assess the in vitro activity of ciprofloxacin in comparison with those of norfloxacin, gentamicin, tobramycin, amikacin, ticarcillin, piperacillin, carbenicillin, cefotaxime and cefoperazone to clinical isolates in Korea including gram-negative enteric bacteria, N. gonorrheae and gram-positive cocci. Minimal inhibitory concentrations were determined by two fold agar dilution method, and all of antibiotics were tested concentration from 0.0009 to 128 ㎍/ml. Ninety percent of enterotoxigenic E. coli, uropathogenic E. coli, Serratia spp., S. typhi, P. aeruginosa, C. freundii, E. cloacae, K. oxytoca, K. pneumoniae, P. vulgaris, M. morganii, S. aureus, S. epidermidis were inhibited at concentrations lower than 0.1㎍/ml. Ninety percent of Alcaligenes spp. were inhibited 0.14㎍/ml, methicillin-resistant S. aureus, at 0.23 ㎍/ml, Campylobacter spp. at 0.46 ㎍/ml, N. gonorrheae at 1.95 ㎍/ml and P. mirabilis at 3.10 ㎍/ml. Compared to norfloxacin, aminoglycosides, semisynthetic pecicillins and cephalosporins, ciprofloxacin showed higher activity against a wide range of gram-negative enteric bacteria, N. gonorrheae and staphylococci including methicillin-resistant S. aureus.

새로운 抗生劑 Colistin에 對한 各種 細菌의 感受性에 關한 實驗

玄瑗,石鍾聲 中央醫學社 1961 中央醫學 Vol.1 No.4

A Method to Fabricate Low-Cost and Large Area Vitreous Carbon Mold for Glass Molded Microstructures

주종현,Sera Lim,석종원,김석민 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.2

A method to fabricate a vitreous carbon (VC) mold for glass molded microstructures was investigated by replicating a microstructuredfuran precursor and carbonization process. The composition of a furan-based thermal curable polymer was optimized along with theprocessing parameters of thermal curing and carbonization processes to improve the surface quality of microcavities on the VC mold. The engineering feasibility of the proposed method was ensured by successfully molding glass micro-grating structures with a pitchof ~46.3 μm and a height of ~3.8 μm using the fabricated VC molds.

腸內棲息菌에 對한 硏究 : 變形菌(Proteus)에 關한 硏究

石鐘聲,金漢壽,張友鉉,李承薰 現代醫學社 1969 現代醫學 Vol.10 No.2

The proteus group are known to be widely distributed in nature and also constitute one of the important micro-flora, of human intestines. The identification of the Proteus and further differentiation into 5 species are made chiefly by their biochemical activities, which are conventionally studied with the cultures grown at 37℃. Since it is known that the metabolic activities of bacteria are influenced by the physicochemical natures of environment, it is conceivable that results of bacterial identification and differentiation based on their biochemical reactions might be different when the culture conditions differ. Thus, 100 strains of the proteus isolated from various clinical specimens were grown aerobically at 37℃ and 22℃ and the patterns of their 1, biochemical activities under the different cultural conditions were studied. The results might be summarized as follows: 1) By the biochemical activities with the cultures grown at 37℃, 100 proteus strains were differentiated into 4 species; P. rettgeri 4, P. vulgaris 14, P. mirabilis 36, and P. morganii 46. 2) If the differentiation into the species was made by the biochemical activities with the cultures grown at 22℃, the 100 strains might be classified into, P. rettgeri 41, P. vulgaris 20, P. mirabilis 34, and P. morganii 5. 3) Regardless the difference of the culture temperatures, 47 strains among the 100 strains were identified into the same species of proteus; P. rettgeri 2, P. vulgaris 7, P. mirabilis 33, and P. morganii 5. 4) Biochemically the proteus strains appeared to be more active at 37℃ than at 22℃. 5) The distribution of the 100 strains among the clinical specimens were stool or recta swat 68, pus or discharge 14, urine 10 and miscelleneous specimen 8.

비결정 탄소 몰드를 이용한 유리 마이크로 구조물 제작

주종현(Jonghyeon Ju),임세라(Sela Lim),한윤아(Yunah Han),석종원(Jongwon Seok),김석민(Seok-min Kim) 한국생산제조학회 2011 한국생산제조시스템학회 학술발표대회 논문집 Vol.2011 No.10

다단계 생산 가공 시스템의 최적화

석종원,강구현,이상조 대한기계학회 1988 대한기계학회 춘추학술대회 Vol.- No.-

퓨란수지를 이용한 글라시 카본 마이크로 몰드 개발

주종현(Jonghyeon Ju),임세라(Sela Lim),김석민(Seok-min Kim),석종원(Jongwon Seok) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

A novel approach is proposed to fabricate a glassy carbon mold with micro cavities for precision glass molding of micro structures. A master pattern was fabricated by photo lithography technique and a mold for casting the furan resin was prepared by PDMS replication process. The furan resin was poured on the PDMS mold and carefully cured in vacuum condition for minimizing the micro pores. Finally, the fabricated polymer precursor was pyrolysized in the inert atmosphere at high temperature and turn to the glassy carbon mold with micro cavities. To minimize the mechanical deformation and degradation of surface properties due to the micro pores, the contents of monomer, initiator, and solvent for precursor, and the processing conditions in the curing and the carbonization stages were optimized. We also analyzed the effects of material contents and processing conditions on the weight loss and volumetric shrinkage during the curing and carbonization processes.

안드로이드 기반 소프트웨어를 위한 테스트 자동화 체계

신원(Won Shin),석종수(Jong-Soo Seok),김태완(Tae-Wan Kim),장천현(Chun-Hyon Chang) 한국정보과학회 2011 한국정보과학회 학술발표논문집 Vol.38 No.1A

최근 들어 스마트폰 시장이 활성화 되면서 휴대기기용 플랫폼인 안드로이드 역시 각강받고 있다. 오픈 플랫폼인 안드로이드에 수많은 제조사들과 개발자들이 가세하면서 다양한 플랫폼 버전이 탑재된 하드웨어가 출시되고 있다. 이처럼 혼재된 안드로이드 환경 때문에 상호호환성 문제와 함께 그에 따른 테스트의 필요성 또한 대두되고 있는 상황이다. 하지만 기존의 연구들은 테스트 케이스 자동 생성에 주로 초점이 맞추어져 있고, 컴파일 및 실행에 있어서 반복적인 작업이 필요한 안드로이드의 특성을 반영하지 못하고 있어 테스트 과정에 과도한 시간이 소모되고 인력 및 비용 또한 손실되고 있다. 이에 본 논문에서는 안드로이드 기반 소프트웨어 테스트 시 고려해야 할 문제점을 분석하여 비효율적인 면을 제거하고 테스트를 자동으로 진행할 수 있는 테스트 자동화 체계를 제안한다. 이를 통해 기존의 테스트 과정에서 과도하게 투입되는 시간, 인력 및 비용을 줄이고 개발 기간이 짧은 안드로이드 소프트웨어 마켓 시장에 효율적으로 대응할 수 있는 이점을 얻을 수 있다.