• KSBB Journal
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• v.11 no.5
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• pp.518-523
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• 1996

The sensor to determine ATPase activities was consisted of an immobilized enzyme membrane(purine nucloside phosphoryrase and xanthine oxidase) and an oxygen electrode. The proposed sensor was used for the determination of $K^+-, Ca^{2}+- and Mg^{2+}-$ATPase activities in several fish muscle proteins such as Thunnus albacares(Yellowfin tuna), Tetrapturus audax(Striped marlin), Prognichthys agoo(Japanese flyingfish), and Cypvinus carpio(Carp). $K^+-, Ca^{2}-$ATPase activities measured by the proposed sensor system were in good agreement with the results obtained by a conventional colorimetric assay. One cycle of assay could be completed within 3mlnutes.

• KSBB Journal
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• v.8 no.2
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• pp.97-103
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• 1993

This study was investigated as a step for the purpose of successful introduction of cytoplasmic inherited characters between the different plants. Cytoplasts were separated from the protoplasts of CMS(cytoplasmic male sterility) line such as MS Burley 21 which carried from Nicotiana megalosiphon. The cytoplasts were fused to protoplasts derived from Nicotiana tabacum Br 64 with PEG(polyethylene g1yco1). The cytoplasts were separated by density gradient centrifugation. Efficient separation of cytoplasts depended on the difference of specific density of gradient solution. However, the iso-osmolality of gradient solution was not important to separate the cytoplasts. The cells for a cybrid were fused with 50% concentration of PEG.

• Archives of design research
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• v.15 no.1
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• pp.5-14
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• 2002

Fractal which was named by Mandelbrot in 1975 and its theory have been taken notice of many fields of scholarship, namely mathematics, physics, geography, architecture, art, philosophy and so on. If we approach Fractal on the basis of the designing cogitation, it can be used not only as one of materials to take a crease thinking in design, also as a due of the methods to assess the design problem with a new point of view. Based on above background, in this study, it was studied on the graphic artist, Morits Collelius Escher who has been well known as the great artist of illusion," and on the attributes of Fractal which were contained in his various work\ulcorner As a reset, the four attributes, namey ′fractal dimension′, ′self-similarity, ′recursiveness′and ′infinity were founded in his works. Also, it was founded that Escher had employed the attributes of Fractal in his almost works for "the representation of the condition of unified-duality," that is to say, for the union of two different dimensions. After this, it is expected that this study shoed be extended to the development of the principle of Fractal-Design on the basis of ′Fractal which can be defined as the phenomenon of repetitious pattern between chaos and order and′the formative beauty of Fractal′.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.5
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• pp.66-73
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• 2000

A new modified command voltage of the third harmonics injected PWM inverter is proposed to control the inverter in overmodulation mode. The third harmonics injected PWM has a extended linear region compared with the sine PWM. But it still has a maximum voltage about 90% compared with the six step inverter. By analyzing the relationship between the modulation index and the peak of the fundamental component of the modified reference voltage, we can settle the problem in over modulation mode without iteration. Then we can increase the maximum fundamental component of the third harmonics injected PWM inverter comparative to six-step inverter continuously in over modulation mode. The simulation results of the inverter-induction motor system shows the validity of this method.

• KSBB Journal
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• v.10 no.4
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• pp.370-373
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• 1995

The major by-products in ethanol fermentation by Saccharomyces cerevisiae were glycerol, acetaldehyde, acetic acid, lactic acid, and formic acid. The effects of these by-products on the cell growth and ethanol production were studied. By adding acetaldehyde or acetic acid in the fermentation broth, the cell growth decreased while the ethanol production increased. But glycerol and lactic acid had nearly no effects on the cell growth and the ethanol production. Acetic acid and acetaldehyde inhibited the cell growth by diminishing the growth rate as well as by prolonging the lag phase. The ethanol yield increased with the elevation of concentrations of acetic acid and acetaldehyde in the fermentation broth. The maximum ethanol yield was obtained for $3g/\ell$ acetic acid and $2g/\ell$ acetaldehyde, respectively.

• KSBB Journal
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• v.11 no.6
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• pp.630-635
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• 1996

Blood plasma proteins dissolved in isotonic phosphate-buffered saline were found to be adsorbed to red blood cell ghosts suspended in the solution. This was evidenced by concentration reduction of the plasma proteins in the bulk solution. For initial concentration of 0.1mg/mL immuno globulin, concentration reduction increased from 14% to 45% as the volume fraction of red blood cell ghosts in the solution increased from 5% to 45%. For initial concentration of 0.075mg/mL albumin, the concentration reduction increased from 12% to 47% as the volume fraction of red blood cell ghosts in the solution increased from 5% to 70%. The concentration reduction of plasma proteins in hardened red blood cell ghosts was higher than that in red blood cell ghosts. The number of adsorbed protein molecules per a red blood cell ghost were reduced as volume fraction of the ghosts in the solution increased.

• KSBB Journal
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• v.9 no.4
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• pp.400-405
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• 1994

The conditions for ${\beta}$-galactosidase production from alkalophilic, thermophilic Bacillus sp. TA-11 were investigated. The maximal enzyme production was obtained when the strain was cultured at $50^{\circ}C$ for 5 days with fed-batch culture in the optimal medium containing 1.5% lactose, 0.6% yeast extract 0.15% $K_2HP0_4$and initial pH 9.5, and then final enzyme activity under the above conditions was 5200 unit/ml of cell free extract.

• KSBB Journal
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• v.9 no.4
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• pp.406-411
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• 1994

An extractive fermentation process was developed to produce citric acid from g1ucose. Citric acid is a strong inhibitor to this fermentation. A mixture of tertiary amine and oleyl alcohol was used to selectively extract citric acid from the fermentation broth, hence enhancing the productivity by over 200%. Although the toxicity of the solvent was significant in the range of higher than 30% of amine, immobilization in polyurethane foam was useful to protect the cells from the toxicity of the solvent.

• KSBB Journal
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• v.9 no.4
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• pp.436-442
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• 1994

The production of itaconic acid by Aspergillus terreus NRRL 1960 was studied. The optimal culture conditional such as pH, inoculum size and medium composition were established. Maximum production of itaconic acid, $19.18g/\ell$, was obtained when the cultivation was carried out at $37^{\circ}C$ and pH 2.5 for 7days, with medium containing 5%(w/v) glucose, 0.5%(w/v) NH4Cl, 0.2%(w/v) yeast extract 0.1%(w/v) CaC12, 0.1%(w/v) MgSO4 and 0.2%(w/v) NaCl. A proper medium for inoculum culture was found to be 2%(w/v) malt extract. The batch production of itaconic acid with free cells in a stirredtank reactor was not efficient compared to the shake-flask culture.

• Proceedings of the KSPS conference
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• 1996.02a
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• pp.1-2
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• 1996

청각의 중요성은 새잠스럽게 말활 필요도 없고 농아가 말못하는 것은 누구나 다 알 수 있는 사실입니다. 그러나 음을 하나하나 습득하고 단어를 하나하나 반복하면서 언어습득을 시작하는 유년기에 있어서 청각은 더욱 독특한 역활을 합니다. 조국에 돌아와서 일하기 시작한지 일년이 조금 넘었으나 최초부터 우리 연구소에 찾아오는 어린이가 구주제국보다 훨씬 연소하고 또 수가 훨씬 많은 데 놀랐습니다. 그 중 대다수가 조음장애라든가 언어지연입니다. 더욱 놀라운 점은 이러한 장애가 정상지능의 어린이에게 많은 것입니다. 일반상식으로 어휘력과 발표력이 부족한 어린이들은 정신지체아와 혼동하게 됩니다. 연구소에 진단받으러 오는 어린이들을 체계적으로 청각 검사를 한 결과를 슬라이드를 통해서 말씀드리겠습나다. 검사받은 어린이 중 50-60%가 청각에 이상이 있는 것이 발견되었습니다. 동반한 어머니들은 너무나 놀라서 "우리 아이는 검사를 받았어요! 모두 정상이라고 그랬어요" 이 엄마 말씀도 정당하고 전검사도 정당활 것입니다. 그러나 이러한 어린이들의 문제는 특수합니다. 즉 경도난청에다 또 일시적 난청이기 때문에 명시에 생활하는 데는 큰 지장이 없고 때에 따라서는 청각이 거의 완전히 회복되고 또 몇 주후에 감기가 들거나 하면 다시 난청이 되는 것입니다. 이러한 난청문제가 일년에 3-4번씩 반복되어 어린이가 만 3-4세가 되면 약 1년간 청확한 음을 청취못한 셈이 됩니다. 조석에 기온차가 대단한 계절, 난방의 발달로 인하여 실내는 영상 24도이고 문 한겹만 열고 나가면 영하 10도 그 차이는 34도, 거리로 나가면 일산화탄소를 뿜고 쾌주 하는 차량, 버스나 트럭에셔 나오는 연기는 키가 작은 어린이 코속으로 직통하고 에어컨 시스댐으로 난방.냉방하는 지하상가, 백화점, 지하철 기타 대건물에는 바이러스 만연의 적절한 곳이 됩니다. 생리적 저항력이 없는 어린이들은 이러한 공해와 생활조건의 제일희생자가 되는 것입니다. 엄마들이 "얘는 감기, 비염, 편도선을 달고 삽니다...." "얘는 코감기, 목감기 번갈아 가면서 하도 앓고 있어서 양약율 중지하고 현재 한약을 먹고 있습니다." 이러한 역경은 극복할 수 있는가\ulcorner 질병의 메카니즘은 어떻게 작용되는가\ulcorner 등등을 육미회 센타에서 체험한 사례를 가지고 말씀드리고자 합니다.