• E2M - 전기 전자와 첨단 소재
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• 제9권8호
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• pp.806-812
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• 1996

I-V characteristics of ground electrode fabricated using an aluminium scrap are presented. We fabricated several shapes of aluminium scraps and aluminium electrodes. The results show that the current of aluminium electrode increased linearly by the voltage increase. AC breakdown voltage of copper plate electrode was higher than that of aluminium electrode. AC breakdown current of aluminium electrode was higher than that of copper plate electrode. As applied voltage increased, grounding resistance of aluminum electrode decreased linearly.

• 대한전기학회논문지
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• 제34권8호
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• pp.323-330
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• 1985

Dielectric loss tangent and ac dielectric strength of GFRP (Glass Fiber Reinforced Plastics, G-10)was investigated as parameters of mechanical and thermal stresses, in order to study the basic dielectrical characteristics of composite insulating materials. The dielectric loss tangent was increased and the ac dielectric strength was decreased with increase in the mechanical stresses beyond the mechanical yield point on account of fiber-matrix debonding, but the dielectric constant was not varied sigificantly. the dielectric strength of G-10 was about 2 MV/cm and the dielectric constant was about 4.8.

• 한국방사선학회논문지
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• 제15권5호
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• pp.649-656
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• 2021

본 연구는 태아의 자궁 내 성장제한을 평가하는 변수로 소뇌횡직경과 복부둘레비(TCD/AC ratio)의 적절성을 평가하고자 하였다. 2019년 4월부터 2021년 3월까지 부산소재 I 병원에서 정기검진으로 초음파를 실시한 784명의 임산부를 대상으로 진행하였으며 소뇌횡직경과 복부둘레 측정값을 통해 후향적으로 분석하였다. 단순회귀분석에서 임신주수에 소뇌횡직경은 97.2%, 복부둘레는 97.5%의 영향력을 보였으며(p<0.001) 정상태아의 TCD/AC ratio는 임신주수에 상관없이 13.2로 결정되었다. 또한 빈도분석을 통해 임신주수 그룹별 TCD/AC ratio의 백분위수를 산출하였으며 자궁 내 성장제한 예측의 95 백분위수는 14.2로 나타났다. 결과적으로 TCD/AC ratio는 태아의 정상적인 성장을 평가하고 IUGR을 예측하는 유용한 변수로 활용될 수 있을 것으로 사료된다.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2385-2391
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• 2018

This paper is devoted to detecting decomposition characteristics of Iodotrifluoromethane ($CF_3I$) under alternating current (AC) discharges or load current interruptions. The decomposition products are measured utilizing chromatography-mass spectroscopy. It is found that less than 1% $CF_3I$ gas decomposed after several interruptions at load current of 200 A or hundred times of AC discharges. However, under interruptions at a current of 400 A, more than 95% $CF_3I$ gas decomposed into carbon tetrafluoride ($CF_4$) and hexafluoroethane ($C_2F_6$). The equilibrium compositions based on Gibbs free energy minimization of $CF_3I$ was calculated to explain the decomposition mechanism.

• 대한전자공학회논문지
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• 제16권2호
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• pp.7-14
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• 1979

Integrated Injecton Logic의 설계를 npn transistor 의 상향전류증폭율, βu 을 중심으로 하여 검토하였다. I2L 기본회로의 DC, AC특성과 npn transistor의 베이스 전류성분을 측정하기 위하여 test structure를 제작하였으며 또한 I2L T flip-flop도 설rP, 제작하였다. 제작된 test structure의 특성은 βe가 10, speed-power product가 2.6p.J/gate, 최소 전달지연 시간이 36 nsec 였으며 T flip-flop은 3.5 MHz 까지 동작하였다.

• Archives of Pharmacal Research
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• 제24권3호
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• pp.229-233
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• 2001

This Paper deals with the development of a technology for making a hydrophilic gel of Polyethylene oxide reception in which radiating ability is employed to cause cross-linking of Polymers in a water solution. The gel of polyethylene oxide was shown to be nontoxic contain 5-50% of polymer and be useful in composite medicinal forms along with biologically active substances including Bac. subtilis proteases. Proteases immobilized in the gel possess high thermal stability and proteolytic activity and are readily applied in medicine. The effect of immobilized proteolytic and glucolytic enzymes of Bac. subtillis (Immozimase) on the warm ischemia-reperfusion (I/R) which can cause hepatic and jejunum injury was also studied. These enzymes were immobilized on water-soluble polymer polyethylene glycol by means of an electron beam. The number of degraanulated mast cells as well as serum ALT after I/R in the group with Immozimase was decreased to almost half as compared with the control group. Pretreatment with Immozimase resulted in significant reduction of hepatic and gut neutrophil accumulation as compared with control animals. It was concluded that Immozimase has a protective effect for hepatic and gut ischemia/reperfusion, and this effect seems to be associated with prevention of leukocyte accumulation .

• 한국초전도ㆍ저온공학회논문지
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• 제10권1호
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• pp.52-56
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• 2008

According to the improvement of HTS conductor, HTS tapes which have the high current capacity have been recently researched in several nations. For large power application, AC loss is the most important issue in the development of AC superconducting power devices because it is closely related to the system operation efficiency. In 1st generation wire of HTS conductor, BSCCO, AC loss is too large to use for power application. Also, It is well known in recently years that YBCO CC, the 2nd generation wire, has also too much AC loss to apply to AC power devices. There are many trials to develop the new HTS wire having the low AC loss around the world. In this research, we present the measurment result of magnetization losses in SmBCO coated conductors. We measured the magnetization loss generated by perpendicularly exposed external magnetic field and compared with the analytic value of the strip model. Also, we presented the results compared with measured magnetization loss of an YBCO coated conductor.

• Journal of Biosystems Engineering
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• 제24권2호
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• pp.123-134
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• 1999

The electrical properties such as dielectric constant, dielectric loss factor and AC conductivity of grain were presented to measure the moisture content of grain using RF impedance. At frequency ranging from 1 to 10MHz and room temperature, $20^{\circ}C$, vector network analyzer(HP4195) and coaxial type sample holder were used to analyze the electrical properties of paddy(11∼24%w.b.), brown rice(11∼18%w.b.), barley(11∼21%w.b.) and wheat(11∼23%w.b.) depending on the moisture content, frequency and bulk density. The dielectric constant and AC conductivity of grain samples increased with moisture content and bulk density. The dielectric constants decreased with frequency and could be expressed as function of the moisture density(decimal moisture $content{\times}bulk$ density).

• 한국연초학회지
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• 제13권2호
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• pp.34-41
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• 1991

To explore the possibility of introducing Zea mays transposable element Ac(activator) which can be used as a mutagen and gene tag in tobacco plants other than maitre, we tried to introduce a cloned Ac element into tobacco cells by an Agrobacterium tumefaciens binary vector system. Transformation of N. babacum cv. Burley 21 tissues and regeneration to whole plant were carried out. The frequency of the transformed callus induced in shoot induction media was higher than that of transformed callus induced in callus induction media. However, the calli were not grown in the second selection media, and became yellow senescent calli. Regenerated tobacco plantlets with foreign gene were also obtained in shoot induction media containing 100 $\mu\textrm{g}$/ml kanamycin and 100$\mu\textrm{g}$/ml carbenicillin. The leaf tissues of transformant was also resistant to 1000 $\mu\textrm{g}$/ml kanamycin. The chromosomal DNAs of transformant and normal plant of N. tabacum were digested by EcoR I and Hind III but not by Pst I.

• 약학회지
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• 제35권2호
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• pp.123-130
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• 1991

Effects of Allolobophora caliginosatrapezoides (Ac) polysaccharide fractions on the inflammation and hypersensitivity were studied in vivo. It showed that Ac polysaccharide fractions have the significant inhibitory activities of inflammation and hypersensitivity; They inhibited significantly the carrageenin-induced paw edema and acetic acid-induced writhing syndrome. They also inhibited significantly the Arthus reaction and delayed hypersensitivity in the sheep red blood cell-sensitized mice in accordance with the inhibition of haemaglutinin titer, haemolysin titer, plaque-forming cells and rosette-forming cells. They also improved markedly the oxazolone-induced dermatitis in rats dose-dependently. As the above results, it exhibited that Ac polysaccharide fraction inhibited not only humoral immune response, but also cell-mediated immune response. It seemed that methanol and ether extracts have also another physiological active agents.