• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1948-1950
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• 1997

In this paper, we compose of the single current source inverter for utility interactive photovoltaic system. According to insert parallel resonant circuit, the do reactor decreases the distortion of dc current and output current. Therefore, we decrease the do reactance and control modulation factor to operation at the maximum power point around of solar cell.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.473-475
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• 1996

In this paper, bilateral variable-ratio dc chopper system for electric vehicle is proposed. We present the method which is able to simplify the main synthetic chopper circuit by selecting among the forward powering, forward regenerative braking, backward powering, and backward regenerative braking only by control signal. By conducting the experiment with separately excited dc motor, it is confirmed that two quadrant chopper can drive four quadrant operation.

• Management & Information Systems Review
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• v.9
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• pp.41-63
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• 2002

Recently junior colleges in Korea have been working to meet changes in industrial and educational surroundings by establishing new departments, integrating and abolishing existing ones, or adjusting departmental quotas. These endeavors need to be based on analysis of industrial policies, both national and international, and of the industrial trend of the region in which the particular college is located. They also need to take into consideration change in educational policies and the direction of the college's specialization. This study aims to provide some foundation materials for these endeavors. As a result, it has considered changes in industrial and educational surroundings and analyzed the whole spectrum of departments existing at Korean junior colleges, with a focus on business-related ones. To summarize, each college offers departments, having taken into consideration its regional, industrial, and educational environments. The result of this study may be utilized by colleges when they establish new departments, integrate and abolish existing ones, and adjust departmental quotas.

• Journal of the Korean Applied Science and Technology
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• v.3 no.2
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• pp.17-22
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• 1986

Compositional and quantitative changes of 4-desmethylsterols in soybean (Glycine max. cv. Gangrim) seed and pod at six stages of development from flowering were investigated. The content of 4-desmethyl-, 4-monomethyl- and 4,4-dimethylsterols in developing soybean seed and pod was found to vary between 0.16-0.35, 0.04-0.12 and 0.04-0.06%, respectively. The predominating 4-desmethylsterols were sitosterol, campesterol and stigmasterol. The proportion of sitosterol in seed decreased to 57.0% with maturation, while in pod increased up to 88.7%. ${\triangle}^{7,22,25}$ Stigmastatrienol estimated 7.5% was detected in the fully mature seed.

• Journal of Environmental Health Sciences
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• v.4 no.1
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• pp.37-40
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• 1977

녹용이 동물체에 미치는 영향을 조사하기 위한 일환으로 녹용 침출액을 집토끼에 주사한 후 여기에서 여섯개의 조직(골격근, 간, 신장, 부신, 비장, 심장근)을 선택 적출하여 disc-gel electrophoresis로 수용성 단백 분획상을 비교 하여 보았다. 대조군과 5일간 주사한 군에서 간, 신장, 부신, 비장에서는 서로 동일한 영동분획상이 나타났으나 골격근과 심장근에서는 대조군보다 실험군(5일간과 15일간 녹용침출액을 주사한 군)의 영동대에서 하나의 영동대가 더 나타났다. 한편 15일간 주사한 실험군과 5일간 주사한 실험군 사이에서는 단백분 획상의 차이점이 없음을 알았다. 이와 같은 변화는 녹용의 어떤 특수성분이 주로 근육형 조직에서만 백질을 합성하는 기작에 영향을 끼친 것이 아닌가 사려된다.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.438-440
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• 1994

The output power of photovoltaic(PV) system is variation due to the change in the insolation, temperature and etc. This problem can be overcome if the system is connected to storage batteries and the power system. According to, this paper propose photovoltaic Voltage Source Inverter, which would be connected utility interactive system. It has been experimentally verified that maximum power can be obtained by varing modulation index(MI).

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.103-108
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• 1996

In this experiments, we introduce the simple method measuring the refractive index and it measured for severial materials compare with real values. Refractive index of distillation water, ethyl alcohol and acryl were $1.32{\pm}0.006$, $0.36{\pm}0.01$ and $0.48{\pm}0.005$, respectively.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.41-51
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• 1996

According to Korean pharmaceutic law, spectacles is a kind of medical device or instrument that is composed of a front and two temples with a pair of lenses. If the spectacle is not worn, it is a kind of optical device, but if it were worn, it will makes a new optical system to correct ametropia. Therefore, spectacles must be carried on by dispensing opticians.

• Journal of radiological science and technology
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• v.15 no.1
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• pp.107-113
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• 1992

Inverter type X-ray apparatus has been introduced and used several hospitals. Principle of inverter type X-ray generators are such as to convert the frequency of commercial power supply to high frequency and to control the high voltages for X-ray tube. Inverter generators are now on the way for futher development to elliminate single phase generators and three phase generators. We compared inverter type X-ray apparatus with conventional single phase 2 peak and three phase 12 peak, apparatus in the following aspects X-ray out put to tube voltage, linearity of X-ray out put to mA, HVL according to mA contrast to kV.

• Journal of radiological science and technology
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• v.2 no.1
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• pp.37-43
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• 1979

High kilovoltage technique as compared with low kilovoltage in taking chest radiogram has much advantages. Authors performed an experiment by using acryl phantom to make the technical chart at 120KV and obtained the results as follows; 1. Increase and decrease of tube voltage in thickness change was 3.2KV per cm at variable technic chart. 2. At fixed kilovoltage technic chart, increase and decrease was $0.12{\sim}0.2$ mAs per cm in chest thickness. 3. Increase and decrease of distance was 1.3inches per cm in thicknese change