• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.961-965
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• 1998

The rapid development of small-scale (1-10 MJ) Superconducting Magnetic Energy Storage Systems (SMES) can be explained by real perspective of practical implementation of these devices in electro power nets. However the serious problem of all high mechanically stressed superconducting coils-problem of training and degradation (decreasing) of operating current still exists. Moreover for SMES systems this problems is more dangerous because of pulsed origin of mechanical stresses-one of the major sources of local heat disturbances in superconducting coils. We investigated acoustic emission (AE) phenomenon on model and 0.5 MJ SMES coils taking into account close correlation of AE and local heat disturbances. Two-coils 0.5 MJ SMES system was developed, manufactured and tested at Russian Research Center in the frames of cooperation with Korean Electrical Engineering Company (KEPCO) [1]. The two-coil SMES operates with the stored energy transmitted between coils in the course of a single cycle with 2 seconds energy transfer time. Maximum operating current 1.55 kA corresponds to 0.5 MF in each coil. The Nb-Ti-based conductor was designed and used for SMES manufacturing. It represents transposed cable made of Nb-Ti strands in copper matrix, several cooper strands and several stainless steel strands. The coils are wound onto fiberglass cylindrical bobbins. To make AE event information more useful a real time instrumentation system was used. Two main measured and computer processed AE parameters were considered: the energy of AE events (E) and the accumulated energy of AE events (E ). Influence of current value in 0.5 MJ coils on E and E was studied. The sensors were installed onto the bobbin and the external surface of magnets. Three levels of initial current were examined: 600A, 1000A, 2450 A. An extraordinary strong dependence of the current level on E and E was observed. The specific features of AE from model coils, operated in sinusoidal vibration current changing mode were investigated. Three current frequency modes were examined: 0.012 Hz, 0.03 Hz and 0.12 Hz. In all modes maximum amplitude 1200 A was realized.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.218-224
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• 2000

The antimicrobial activities of chitosan oligosaccharide(chitohexaose) and two types of chitosans M.W.(10,000 and M.W. 100,000) were examined against Escherichia coli O157 : H7(ATCC 43894), Staphylococcus aureus(ATCC 144458) and Candida albicans(KFRI 432). Chitosan with molecular weight of 10,000 showed the strongest antimicrobial activities to E. coil O157 : H7 and S. aureus, whereas chitohexaose acted most strongly against C. albicans. The most effective concentration of chitosan was measured to be 0.1 mg/mL for E. coil O157 : H7 and S. aureus, and that of chitohexaose to be 1 mg/mL for C. albicans. Antimicrobial activities of chitosans and chitohexaose were maintained for 60 min after their treatment. They were found to induce leakage of intracellular proteins and nucleic acids from treated microorganisms. The efflux determined by assaying the ${\beta}-galactosidase$ leaked from the lactose-induced E. coli O157 : H7 cells was observed to reach the highest level within 60 min after treatment with the antimicrobial agents and chitosan with 10,000 molecular weight gave the highest ${\beta}-galactosidase$ activity. Therefore, it is supposed that the antimicrobial activity of chitosan with its unique polycationic nature might be caused by its binding to anionic component(s) of the cell envelope and thereby inhibiting the membrane metabolism and/or leaking intracellular materials.

• Journal of the Korean Society of Radiology
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• v.12 no.4
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• pp.475-480
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• 2018

In lower abdominal MRI scan, patients have been tested by physically contacting with the body array coil. In this study, we have designed the acrylic assistant equipment (ACR) which allows the contactless scan of the patient to the coil and evaluated the feasibility by comparing the acquired images with ACR to those obtained without ACR. We tested 10 cases (F: 5, m: 5) by using the Ingenia $3.0T^{TM}$ MR system and dStreamTM torso coil (Philips Healthcare, Netherlands). We implemented T1 AX TSE and eTHRIVE (GRE) techniques. The scanned images were quantitatively and qualitatively assessed. In qualitatively, the TSE shows 4.44 and 4.56 mean values with and without the ACR and 4.34 and 4.28 at the GRE, respectively. In quantitatively, the TSE shows 12.15 CNR, 17.95 SNR and 12.71 CNR, 18.96 SNR with and without the ACR. And GRE shows 17.72 CNR, 22.59 SNR and 18.26 CNR, 24.47 SNR with and without the ACR, respectively. We have designed and implemented the acrylic assistant equipment to lower abdominal patients. Our data indicate that it is possible to obtain similar image qualities to current lower abdominal MRI scan without the physical contact to the patient.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.59-59
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• 1993

비방사능물질인 Biotin을 DNA probe에 표지하여 nonisotopic hybridization 방법을 사용하여 감도를 높임으로써, 손쉽게 생물공학 의약품의 품질관리에 사용되도록 하였다. Bethesda Research Laboratories(BRL) 회사 제품인 biotinylated probes-avidin alkaline phosphatase를 이용한 chemiluminescene detection방법으로 행하여 λ phage DNA, yeast DNA, E.coil DNA의 한계 검출 농도를 알아내고, 생물 공학 제품에 적용하였다. Dot blot hybridization 방법으로 행하여 λ phage DNA는 0.1pg, Yeast DHA는 4.5pg, E. coli DNA는 8.9pg까지 검출되었고, 기존 생물공학 제품에서는 숙주 유래 DNA가 전혀 검출되지 않았다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.81-81
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• 1993

Reverse transcriptase가 유도되는 것을 SDS-PAGE 및 효소활성 분석으로 확인할 수 있었으며 효소의 정제를 위한 예비실험으로 ammonium sulfate 및 DEAE cellulose ion exchange chromatorgraphy를 시행하였을 때 specific activity의 증가를 보여주므로서 reverse transcriptase의 분자클로닝 후 발현된 효소가 활성을 갖고 있음을 알 수 있었다. pMAL; cRI 재조합 유전자에 있는 protease의 유전자 발현을 유도했을 때 E. coli세포의 성장에 toxic하게 작용함을 관찰할 수 있었다. 이는 발현된 protease가 E. coil의 번식에 영향을 주는 것으로 믿어지며 Protease의 유전자 발현을 위한 host의 선택, inducer의 첨가시간 등 실험조건의 확립이 필요할 것으로 사료된다.

• Proceedings of the Korean Vacuum Society Conference
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• 2007.02a
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• pp.197-197
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.113-114
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• 2009

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.233.2-233
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• 1996

No Abstract, See Full Text

• Proceedings of the Korean Magnestics Society Conference
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• 2005.12a
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• pp.48-50
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• 2005

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.583-584
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• 2011