• 대한수의학회지
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• 제24권2호
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• pp.149-162
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• 1984

The research was conducted(1) to confirm the agent(s) responsible for the antimicrobial activity contained in the fermented tomato juice with L. acidophilus(2) to extract and purify the antimicrobial agent(s)(3) to find the biological, physical and chemical properties of the agent(s). The following results were obtained and summarized as followings; 1. The agent responsible for the inhibitory activity was confirmed by both well assay method using fermented tomato juice with L. acidophilus and turbidimetric technique using the cell-free filtrate or neutralized filtrate of tomato acidohilus culture and found exerted antimicrobial agent other than lactic acid. 2. The procedures of purification : The isolation and purification of antimicrobial agent from the lyophilized acidophilus tomato culture were carried out by (1) methanol extraction (2) acetone extraction, (3) Sephadex G-50 gel filtration (4) paper chromatography and (5) thin layer chromatography. 3. The biological, physical and chemical properties of antimicrobial agent: The biological, physical, chemical properties of the purified antimicrobial agent were: (1) The antimicrobial activity was strong against test organisms; Bacillus subtilis(ATCC 6633), Escheichia coli(ATCC 25922), Staphylococcus aureus(ATCC 167), Pseudomonas fluorescens(KFCC 32394), Proteus vulgaris and Shigella dysenteriae. (2) The pH value of the agent was 2.0 and the inhibitory activity was lost when it was neutralized at 7.0 of pH and the agent was heat stable at $121^{\circ}C$ for 60 minutes. (3) The ultraviolet light absorption spectra of methanol-acetone extract and TLC fraction exhibited a maximum absorption at 260nm and 224nm respectively. (4) The most purified agent from TLC plate increased about 130-fold in activity. (5) The agent isolated from TLC plate was free from $H_2O_2$ or lactic acid. 4. Bioautographic assy: By means of bioautography of the agent on silica gel of TLC plate a strong inhibitory activity against B. subtilis was demonstrated. 5. Mass spectrometry: The agent obtained from TLC plate was analyzed by mass spectrometry which show the parent peak at m/e 264 suggesting the molecular weight of the compound and molecular group such as [$C_2H{^+}_4$], [CO], [CH=NH], [$C_3{H^}4_7$], [$\begin{array}{rcl}O\\{\parallel}\\CH_3-C\\\end{array}$], [$C_6-H{^+}_{11}$], [$C_5H{^+}_{11}$], [$\begin{array}{rcl}O\\{\parallel}\\C_5H_7-C^+\\\end{array}$] were suggested.

• 한국화재소방학회논문지
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• 제34권2호
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• pp.147-155
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• 2020

본 논문은 ESS 화재전용 소화약제 및 소화시스템 개발에 관한 연구이다. ESS 화재를 진압하기 위해 제작된 소화약제는 침윤제 타입으로 주된 소화효과인 냉각작용과 더불어 질식작용과 함께 표면장력 및 점도를 낮춘 침투성이 높은 소화약제로 ESS 모듈 내부의 배터리 셀까지 소화약제가 침투 가능한 특징이 있다. 소화시스템의 경우 랙 단위로 화재를 진압하는 국소방출방식으로 설계하였고, 소화효과를 극대화하기 위해 랙에 장착되는 일반형 노즐과 ESS 모듈 후면 홀에 삽입하는 360° 회전형 노즐을 제작하고, 가스방출압력에 의해 소화약제가 강하게 방사되도록 하였다. ESS 모듈 1단위 및 모듈 3단위 화재진압성능 실험결과 소화약제 방사 후 각각 8 s 및 9 s 만에 눈에 보이는 화염이 모두 소멸되었다. 또한, 소화약제 방사종료 후 600 s 동안 재발화 여부를 확인한 결과 모든 화재진압성능 실험에서 재발화가 일어나지 않고 ESS 화재가 완벽히 진압되는 것을 확인할 수 있었다.

• 접착 및 계면
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• 제24권4호
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• pp.124-130
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• 2023

외부 온도 변화에 따른 특성변화가 적어야 하는 자동차 부품용 코팅제는 외부 환경 변화에 의한 노이즈 특성 변화가 매우 중요하다. 이에 내한성, 내후성, 내마모성이 우수한 연질의 폴리우레탄과 하이드록시 말단 혹은 곁사슬이 아민으로 변성된 폴리실록산 등이 널리 사용되고 있다. 본 연구에서는 각각의 폴리머 성분들이 노이즈에 미치는 영향을 확인하기 위하여 수분산 폴리우레탄을 합성하였고, 폴리실록산, ultra high molecular polypropylene (UHMWPP) 분말, 카본블랙, 소광제를 첨가하여 코팅제를 제조하였다. 수분산 폴리우레탄의 hard/soft 세그먼트의 함량을 27.1%/72.9%, 아민으로 변성된 폴리실록산과 하이드록시 말단 폴리실록산이 2:7의 비율에서 노이즈의 발생이 가장 적었으며, 마찰자가 고속에서 움직일 때 마찰계수의 차이가 컸다. 또한 SiO₂를 UHMWPP 분말로 대체함으로써, 노이즈가 감소하였으며 광택도 또한 감소하였다.

• 동력기계공학회지
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• 제8권3호
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• pp.36-43
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• 2004

The effect of bath composition, plating condition and plating rate on the magnetic property of electroless Co-Cu-P deposits were investigated. With increasing $CuCl_2$ concentration in the bath, plating rate increased, while the Br value of deposit decreased sharply. Deposited surface were inferiority by the increase pH above 10.5, bath temperature higher than $80^{\circ}C$. Plating reaction had been ceased by the increase of pH above 11, bath temperature higher than $90^{\circ}C$ and under $40^{\circ}C$. The Br value of deposit was uniform with various concentration of complexing agent(sodium citrate) in the bath. The Br value of deposit was almost equal to that found by the addition of stabilizer (thiourea) and accelerator(NaF). The Br value of deposit was uniform in plating time(20min) and heat treatment temperature(below $200^{\circ}C$), and were confirmed to have adequate bath stability for practical use.

• Archives of Pharmacal Research
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• 제19권5호
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• pp.348-352
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• 1996

The antioxidant efficacy of aspalatone, a new antithrombotic agent, has been recognized in the neurotoxic model and in the cardiotoxic model in proliminary studies. We examined the specific activity of antiosidnat enzyme in the rat blood following administrations of aspirin, maltol, aspirin together with maltol, salicylmaltol (major metabolite of aspalatone) and aspalatone, respectively. Our assessment showed that salicylmaltol, maltol, aspalatone enhanced antiperoxidative activity. In addition, neither aspirin nor combination of aspirin and maltol, showed any significant effect on the activity of antioxidant enzyme. Because $H_{2}$$O_{2}$ accumulation may stimulate the thrombogenesis in blood, the result suggests that the induction of blood antiperoxidative activity produced by aspalatone may have beneficial effects on the thrombogenesis.

• 한국환경보건학회지
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• 제26권2호
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• pp.30-33
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• 2000

The objective of this study is to examine the subsitiution effect of the waste oyster shell powder as the conditioning agent in municipal wasterwater sludge dewatering process. Beacuse the oyster shells have a large amount(about 38% by weight) of alkaline minerals, such as calcium and magnesium, they are thought to have the potential as a good conditioning agent. In this study, the physico-chemical properties of powdered oyster shells (75${\mu}{\textrm}{m}$ or 200 mesh) and the dewatering characteristics of municipal waste water sludge using powdered oyster shells and CaCO3 are investigated. The conclusions are as follows, 1. Oyster shell could produce calcium ions up to 14ppm at pH-7.0, and this represents that oyster shell is a potential properties as a good conditioner. 2. 100ml of wastewater sludges, conditioned with pretreated oyster shell, are dewatered to the level of 25% solid concentration. 3. Wasterwater sludges, conditioned with oyster shell and CaCO3 are dewatered to the level of 32% solid concentration. And this shows that two-stage combined conditioning process is desirable than the one-stage conditioning process.

• Clinical and Experimental Pediatrics
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• 제63권4호
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• pp.119-124
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• 2020

A cluster of severe pneumonia of unknown etiology in Wuhan City, Hubei province in China emerged in December 2019. A novel coronavirus named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was isolated from lower respiratory tract sample as the causative agent. The current outbreak of infections with SARS-CoV-2 is termed Coronavirus Disease 2019 (COVID-19) by the World Health Organization (WHO). COVID-19 rapidly spread into at least 114 countries and killed more than 4,000 people by March 11 2020. WHO officially declared COVID-19 a pandemic on March 11, 2020. There have been 2 novel coronavirus outbreaks in the past 2 decades. The outbreak of severe acute respiratory syndrome (SARS) in 2002-2003 caused by SARS-CoV had a case fatality rate of around 10% (8,098 confirmed cases and 774 deaths), while Middle East respiratory syndrome (MERS) caused by MERS-CoV killed 861 people out of a total 2,502 confirmed cases between 2012 and 2019. The purpose of this review is to summarize known-to-date information about SARS-CoV-2, transmission of SARS-CoV-2, and clinical features.

• Archives of Pharmacal Research
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• 제17권3호
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• pp.161-165
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• 1994

New hypolipaemic agents, in which benzotriazole moiety is connected to tetrahydro-4-hydroxy-2H-pyran-2-one by a two-carbon bridge, were designed and synthesized to show sinificant cholesterol-lowering effect comparable to mevinolin.

• 대한미생물학회지
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• 제15권1호
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• pp.33-38
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• 1980

Shigella remains to be an important enteric pathogen in this country for the moment. Moreover, since 1978, most of the isolates have become resistant to ampicillin and co-trimoxazole, which used to be the drugs of choice for shigellosis. Since a disc diffusion technique alone has been used in our routine susceptibility test, the minimum inhibitory concentrations(MIC) of both ampicillin and co-trimoxazole to Shigella have never been known. In order to determine these, 195 isolates were tested by an agar dilution method, all of which were isolated at Yonsei Medical Center during the period of June 1978 to July 1980. The following results were obtained. 1. Sixty cultures(29.7%) were susceptible to ampicillin, being the MIC of 8 ${\mu}g/ml$ or less and 53(27.2%) were susceptible to co-trimoxazole, being the MIC of TMP/SMZ 4/76 ${\mu}g/ml$ or less. S. flexneri type 2 was often resistant to both antimicrobic agents. 2. An increasing rate of resistant isolates was noted, particularly in the year of 1979. 3. Many isolates were resistant to both agents. Somewhat more cultures. were ampicillin susceptible and co-trimoxazole resistant than the other way around. It seems that the determination of species or even serotypes might be of help sometimes to select proper antimicrobic agent to control the infection. A routine antimicrobic susceptibility test of Shigella to both ampicillin and co-trimoxazole would be advisable for a better selection of chemotherapeutic agent.

• E2M - 전기 전자와 첨단 소재
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• 제9권2호
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• pp.152-158
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• 1996

Optical absorption and photoconductivity spectra of undoped and Co-doped Cd$_{4}$GeSe$_{6}$ single crystals, grown by the chemical transport reaction using iodine as a transporting agent, were investigated. At 20K, the optical energy gaps of the single crystals are 1.934eV for Cd$_{4}$GeSe$_{6}$ and 1.815eV for Cd$_{4}$GeSe$_{6}$ :Co$^{2+}$. The photoconductivity spectra of these single crystals were closely investigated over the temperature range 20-290K. At 20K, the photoconductivity peaks were located at 1.797eV, 1.347eV for Cd$_{4}$GeSe$_{6}$ and 1.815eV, I,.57eV, 1.46eV and 1.38eV for Cd$_{4}$GeSe$_{6}$ :Co$^{2+}$, respectively.ely.