Cementation 법에 의한 흑연 분말상의 구리 코팅

양승봉,민봉기,정동호,최순돈 영남대학교 공업기술연구소 2000 工業技術硏究所論文集 Vol.28 No.2

We studied the copper cementation and homogeneous coating on the graphite powder by changing the activation temperature and the amount of wetting agent. When we peformed the activation process above 380℃, we were able to achieve the homogeneous copper coating layer on the graphite powder. However, it was impossible to get the homogeneous coating layer on the graphite powder without the activation process. In addition, wetting process on the graphite powder is essential for improving the efficiency of copper cementation. As a result, the optimum condition for copper coating on the graphite by cementation is to add 1㎖ glacial acetic acid and mix with 7g copper sulphate(CuSO4 · 5H2O) and 2g zinc.

N,??-술피닐 비스 1,2,4-트리아졸을 이용한 에스테르와 β-락탐의 합성

양성봉 울산대학교 1990 연구논문집 Vol.21 No.1

N,??-슬피닐 비스-1,2,4-트리아졸은 THF용매에서 SOCI₂,아민 및 1,2,4-트리아졸로부터 쉽게 만들어진다. 이 화합물은 카르복시산의 직접 에스테르와 축합제로, 또한 β-아미노산으로부터 β-락탐을 만드는 탈수제로 이용될 수 있었다. 이 방법을 몇가지 카르복시산과 β-아미노산에 적용시켜 보았다. 이 합성시약의 이점은 첫째 반응 후 형성되는 1,2,4-트리아졸이 중성이기 때문에 대부분의 반응이 거의 중성에서 이루어질 수 있다는 점과 둘째로 1,2,4-트리아졸이 물에 잘 녹기 때문에 일반적인 물에 의한 처리로 생성물을 정제할 수 있어서 유기합성에 흔히 사용되는 크로마토그라피에 의한 분리가 요구되지 않는다는 점이다. N,??-Sulfinyl bis-1,2,4-triazole was conveniently prepared by the reaction of thionlyl chloride with 1,2,4-triazole. The reagent was efficient for the direct esterification of carboxylic acids and could be used as dehydrating reagent for the preparation of β-lactams form several β-amino acids. Several noteworthy featrures of this reagent are apparent as compared with previously known reagents. First, since the 1,2,4-triazole formed as only byproduct is a neutral compound, the reactions occur normally under neutral conditions. Second, the present methods are much simpler and less laborious than the conventional methods because obtained byproduct, 1,2,4-triazole can be easily removed by the usual aqueous workup and does not required chromatographic separation in most cases.

고양이 위 평활근 수축에 대한 Vanadate와 Pervanadate의 효과

심상수,최효봉,심혜선,이덕주,윤신희,한상준,김명석,조양혁 大韓消化器病學會 1999 大韓消化器病學會誌 Vol.33 No.1

포도상구균의 약제 내성 및 β-lactamase의 생산에 관하여

양재윤,박상욱,이용진,조규봉,이연태 단국대학교 신소재기술연구소 1994 신소재 Vol.4 No.-

항균제의 오남용으로 내성균의 출혈빈도가 매우 높아져 임상가에서는 환자치료에 어려움이 적지 않다. 특히 많은 균종중에서 병원감염의 문제가 되고 있고 포도상구균에 대한 내성빈도는 환자치료에 중요하다고 판단된다. 따라서, 1992년 12월부터 1993년 2월 사이에 서울대 병원에 내원(來院)한 환자로부터 총 108주의 포도상구균을 분양 받아 항균제 내성검사를 실시하였고 황색포도상구균의 경우는 β-lactamase 생산유무 확인 및 methicillin에 대한 MIC 농도를 비교하였으며, methicillin에 대하여 각기 다른 MIC농도를 갖는 균종에 대한 substrate 분해능 검사를 실시하여 다음과 같은 결론을 얻었다 (1). 항균제 내성검사를 실시한 108주의 포도상구균은 penicillin에 가장 높은 내성을 나타냈다. 황색포도상 구균의 경우는 97%, 표피포도상 구균의 경우 100%, coagulase 음성포도상구균의 경우 95.7%로 나타났다 (2). vancomycin의 경우는 전 균주가 감수성을 나타냈다 (3). methicillin에 대한 내성율은 41.4%로 나타났다. 이 내성균주들은 10가지 검사 항생제중 최고 9가지에 대한 항균제 내성을 나타내어 다약제 내성임을 알 수 있었다 (4). β-lactamase 생산 실험에서는 58균주의 황색포도상 구균중 53주가 양성을 나타내어 91.4%의 결과를 얻었다. β-lactamase 생산균주와 methicillin에 대한 내성균주가 반드시 일치하지는 않았다 (5). Spectrophotometric assay에서는 내성이 높은 균주와 낮은 균주간에 β-lactamase에 의한 substrate 분해능이 서로 유사하게 나와 황색포도상 구균의 methicililin에 대한 내성 획득은 β-lactamase 뿐만이 아닌 penicillin binding protein(PBP)의 구조적 변화로 인한 내성획득도 시사함을 알 수 있다. One hundred and eight Staphylococcus aureus strains were isolated from patients of Seoul National University Hospital from December 1992 to Feburary 1993. All strains were tested for their sensitivities against antibiotics. β-lactamse producing test was also performed in order to know the relationship between the methicillin resistance and β-lactamase production. Its activity was determined by direct spectrophotometric method. Initial velocities of hydrolysis of the antibiotics were monitored at wavelength 323 nm which corresponded to maximal change in absorbance between the unhydrolyzed substrate and the hydrolyzed product. The results are summarized as follows: 1. In antibiotics sensitivity test of 108 isolated strains of Staphylococcus, they showed hightest resistance to penicillin but all of tested strains were susceptible to vancomycin. 2. 41.4% of them showed resistance to methicillin. 3. All methicillin resistant strains were found to be multi-drug resistant, from 3 to 9 antibiotics. 4. 91.4%(53 out of 58) produced β-lactamase, β-lactamase producing strains did not always coincide with the methicillin resistant strains. 5. β-lactamase activities were similar among staphylococus strains, irrespective of their methicillin resistance.

영아 천식의 임상적 고찰 : Asthma prospective score에 의한 Based on Asthma Prospective Score

양은석,노영일,문경래,박영봉,박상기,변주남 조선대학교 부설 의학연구소 1999 The Medical Journal of Chosun University Vol.24 No.1

A Clinical study was made on 40 patients for infantile asthma less than 2 years old who had been admitted to the Department of Pediatrics of Chosun University Hospital from January 1997 to December 1998. We evaluated family history of allergic diseases, clinical features, serum IgE level, eosinophilia, chest radiologic findings and response to bronchodilator. The results obtained were as follows ; 1) The male to female ratio of patients studied was 4 : 1. 2) Eighteen of the 40 patients (45.0%) had a family history of allergic diseases, of which 10 patients had maternal allergic diseases. 3) Atopic dermatitis was the most common disease (37.5%) among the associated allergic diseases. 4) Thirty two of the 40 patients (80.0%) showed high serum total 19E levels. 5) Only 5 of the 20 patients who were examined by MAST showed positive reaction. 6) The frequency of chest radiologic findings observed in these patients was as follows ; hyperinflation (52.5%), increased bronchovascular marking(30.0%), no pathologic findings(25.0%), and pneumonic infiltration(25.0%). 7) In response to bronchodilator 28 cases(70.0%) were effective. 8) When we divided the 40 patients into two groups by the diagnostic criteria of Asthma prospective score (AP score), 30 patients(75.0%) were included in a compatible group. On the basis of AP score, family history of major or minor allergic dieases and the responsiveness to bronchodilator were important factors for the diagnosis of asthma.

사람 뇌척수액중 Transthyretin의 항산화작용

양성렬,최기오,박종근,류문희,홍석노,김수한,안봉환,이제혁,이민화 대한신경외과학회 1994 Journal of Korean neurosurgical society Vol.23 No.4

Protective effects of human cerebrospinal fluid antioxidants against enzyme inactivation caused by metal-catalyzed oxidation systems were investigated. When purified glutamine synthetase(GS) was incubated with human cerebrospinal fluid(CSF), the enzyme was progressively inactivated. Catalase and EDTA could inhibit the enzyme inactivation by 50-80%. Small-molecular(Mr< -10,000) fraction of CSF inactivated the exogenous GS, but large-molecular(Mr> -10,000) fraction did not. The GS inactivation by the small-molecular fraction was also markedly inhibited by catalase and EDTA. These results suggested that metal-catalyzed oxidation is involved in the GS inactivation by the small-molecular fraction of CSF. Dithiothreitol(DTT) was shown to inhibit almost completely the oxidative inactivation of GS by CSF. However, DTT inhibited only partially the oxidative inactivation of GS caused by small-molecular fraction of CSF. When large-molecular fraction of CSF was separated by anion-exchange HPLC chromatogrpahy, there was a peak of antioxidant activity inhibiting the small-molecular fraction-induced GS inactivation in the presence of DTT. The antioxidant activity was neutralized by monoclonal antibodies to transthyretin. Purified transthyretin was found to efficiently inhibit ascorbate/Cu^(2+)-induced GS inactivation in the presence of DTT. Uric acid and glucose did not show any protective effect on the GS inactivation in the same condition. The above results suggest that metal-catalyzed oxidation occurs normally in human CSF, and that transthyretin may play an important role as a CSF antioxidant in protecting proteins from metal-catalyzed oxidation.

얇은 도핑조절 a-Si:H초격자에서 지속 광전기 전도도

康聖洙,梁承勳,李原鎭,金英鳳,孔維庠,朴相俊,崔時永 慶北大學校 1990 論文集 Vol.49 No.-

Very large PPC effect(σ_ppc/σ_A=10^5) in doping-modulated npnp a-Si: H superlattices could be obtained. B and P atoms, respectively, diffuse and so some parts compensated. Therefore, annealing activation energy of E_a=0.67eV is larger than one of reference n-type sample of E_a=0.26eV and annealing dark conductivity of σ_A=4×10^-[ohm cm]^-1 is lower than that of n-type reference sample of σ_A=2×10 exp (4)[ohm cm]^-1. From this results, very large PPC relatively have obtained. In this paper, we have observed that PPC effect depends on temperature and exposure time. On the basis of the experimental results, we discuss the existing models.

廢 乾電池로 부터 有價金屬의 循環利用

李成植,金種和,姜奉根,梁種奎 동아대학교 환경문제연구소 1991 硏究報告 Vol.14 No.1

The recovery and recycling of the rare metal from spent batteries have been investigated. It was proposed the synthetic processes of recovery of rare metal from various spent batteries, and spent batteries have to be considered as a resource and the collection system with separation should be established.

이방성 이종재료 내의 Ⅴ-노치 균열에 대한 응력특이성의 수치해석적 연구

조상봉,양장흥 경남대학교 신소재연구소 1997 論文集 Vol.9 No.-

이방성 이종재료 내의 V-노치 균열에 대한 응력특이성을 구하기 위하여 복소응력함수의 형태를 제안한 바 있다. 제안된 복소응력함수를 이용하여 특성방성식을 만들고 상용 수치해석 프로그램의 하나 인 MATHEMATICA를 이용하여 특성방정식을 풀어 고유치를 구하였다. The form of complex stress function had been proposed t o obtain stress sinlgularities and coefficient vectors for V-notched cracks in anisotropic dissimilar materials. The characteristic equation for V-notched cracks in anisotropic dissimilar materials was obtained using the complex stress function and was solved by a commercial numerical program, MATHEMATICA.

한약 탕제분획의 항 Herpes simplex virus 활성에 관한 연구

강봉주,고병섭,양기상,박갑주 한국한의학연구원 1996 한국한의학연구원논문집 Vol.2 No.1

Herpes simplex viruses(HSV) are one of the most common infectious virus of man. Though chemotherapies and antiviotics against HSV have been developed in many countries, but anti-HSV agents were not satisfactory to mankind by their toxic reaction and side effects. In order to search for anti-HSV agents from Korean traditional prescriptions, we extended the number of specimens. Both methanol extract and boiling water extract of the Korean traditional prescriptions were screened to detect anti-HSV activities by MTT assay. Korean traditional prescriptions showing anti-HSV activities as methanol extracts were Paekyo˘psan, Chesu˘pwilyu˘ngtang, Yongdamsangantang, and prescription 11. Four methanol extracts showing anti- HSV activities were fractionated by hexane and their efficacies were tested. Hexane fractionations of Paekyo˘psan, Chesu˘pwilyu˘ngtang, and prescription 11 showed in anti-HSV in tissue culture and their selectivity indexes (SI) were 19.50, 3.32 and 42.90, respectively. Methanol fractionation of Paekyo˘psan showed anti-HSV activities and its SI was 1.40. Especially Paekyo˘psan showed anti-HSV activities both haxane and methanol fractionation.