• 열처리공학회지
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• 제12권1호
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• pp.21-30
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• 1999

The present study were investigated changes of precipitation behaviour of laves phase in ferrite single phase and ferrite-martensite dual phase and precipitation of laves phase under stress. Hardness changes in ferrite phase appeared two hardness peaks by precipitation of initial fine precipitator and laves phase in 3Mo-0.3Si and 3Mo-0.3Si-C specimens, respectively. Hardness changes in martensite phase of 3Mo-0.3Si-C specimen was lower in the initial stage of aging by carbide precipitation and after this, increased by re-hardening due to precipitation of laves phase. In the ferrite phase, laves phase was mainly precipitated, whereas in the martensite phase, carbide was preferentially formed during the initial stage of aging and with increasing aging time, laves phase and carbide were simultaneously precipitated by precipitation of laves phase at around carbide. In the ferrite-martensite interface, laves phase was mainly precipitated and carbide was mainly formed at boundary of lath martensite than grain boundary. Adding the stress in aging, fine precipitator of inital precipitation of laves phase precipitated in (100) of perpendicular to tensile direction and has grown to only followed<010>direction and also, volume fraction of laves phase increased. Consequently, the stress added was accelerated initial precipitation of laves phase.

• 전기의세계
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• 제13권2호
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• pp.1-4
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• 1964

Phase transformation is used to change some phase from phase in A.C. system. We have been used Scott or Fork connection in phase transformation the otherwise phase transformation was constructed from M-G set. From this M-G set, we could make phase shift facilities by mannual. Now, I can derive more easy phase transformation from taking another method. I believe this new phase transformation method in the first thing in the world. And so, I am going to explain about phase transformer construction process. The first, we could devide into equal part of core around the iron core as to be same size. The second, you will make primary and secondary winding on the core. The third, when you will supplied three phase A.C. at the terminal of primary winding you can get e.m.f. inducing of some phase at secondary. And so, we could make phase change from some phase A.C. We can apply this principle in many fields, i.e., freequency changer, phase leader of no use condenser, voltage regulator in keeping balance, and D.C. generator. And more, I will introduce in details concerning main pinciple and theory through following chapter.

• 전기학회논문지
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• 제56권11호
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• pp.1930-1936
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• 2007

According to previously published paper the phase advance angle is adopted to the BLDC motor drive with high speed. The report proposed describes the optimum algorism that phase current is in phase with the initial flat region of back EMF. This report studies the need of more leading phase advance angle compared with in phase concept between phase current and back EMF. In case of high reactance this report proposes the more phase advance angle than in phase. The test results more rms value of phase current and output power due to more phase advance angle than in phase. It will be helped the high power operation of BLDC motor at high speed.

• 전기학회논문지
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• 제66권3호
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• pp.587-592
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• 2017

In the three-phase four-wire low-voltage power distribution equipment, single-phase and three-phase load have been used mainly mixed. Also linear and nonlinear loads have been used together in the same conditions. In a three-phase four-wire distribution line, the current distribution of three-phase linear load is almost constant in each phase during driving or stopping, but the single-phase load is different from each other for each phase in accordance with the operation and stop. So that the voltage unbalance is caused by the current difference of each phase. In the three-phase four-wire distribution system, non-linear load is used with linear load. The presence of single-phase nonlinear loads can produce an increase in harmonic currents in three-phase and neutral line. It can also cause voltage unbalance. In the present study, we analyzed for the voltage unbalance fluctuations by the operation pattern of the single and three-phase linear and non-linear load in three-phase four-wire low voltage distribution system.

• Journal of Power Electronics
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• 제16권1호
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• pp.18-26
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• 2016

This paper proposes a compensation algorithm for reducing a specific ripple component on synchronous reference frame phase locked loop (SRF-PLL) in grid-tied single-phase inverters. In general, SRF-PLL, which is based on all-pass filter to generate virtual voltage, is widely used to estimate the grid phase angle in a single-phase system. In reality, the estimated grid phase angle might be distorted because the phase difference between actual and virtual voltages is not 90 degrees. That is, the phase error is caused by the difference between cut-off frequency of all-pass filter and grid frequency under grid frequency variation. Therefore, the effects on phase angle and output current attributed to the phase error are mathematically analyzed in this paper. In addition, the proportional resonant (PR) controller is adapted to reduce the effects of phase error. The validity of the proposed algorithm is verified through several simulations and experiments.

• 대한의생명과학회지
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• 제5권1호
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• pp.67-74
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• 1999

주ㆍ야 (day, night phase) 시차에 따른 toluene 대사를 검토할 목적으로 흰쥐에 50% toluene (olive oil과 toluene의 동량혼합액)을 체중 100 g 당 0.2 ml씩 밤 12시, 낮 12시에 각각 투여한 다음 각각 8시간 후에 처치하여, 다음과 같은 결과를 얻었다. 간 microsomal aniline hydroxylase 활성은 night phase군이 day phase군 보다 대조군 및 toluene 투여군 모두 높게 나타났으며, cytosol의 benzylalcohol dehydrogenase (BADH) 활성은 night phase군과 day phase군간에 별다른 차이를 볼 수 없었으나, toluene 투여시에는 night phase군이 day phase군 보다 효소의 활성도가 오히려 억제되었다. 또한 간 조직의 benzaldehyde dehydrogenase (BALDH) 활성은 night phase군이 day phase군 보다 다소 높게 나타나는 경향을 보였으며, toluene 투여시에는 night phase군에서는 대조군 보다 오히려 감소되었으나 day phase 군에서는 높게 나타나는 경향을 보였다. 그리고 in vitro 시험에서 benzylalcohol 및 benzaldehyde가 BADH 및 BALDH 활성을 억제시킴이 관찰되었다. 요 중 hippuric acid 함량은 대조군 및 toluene 투여군 모두 night phase군과 day phase군간에는 별다른 차이를 볼 수가 없었다. 한편 toluene 투여로 인한 체중 당간 무게 및 혈청 xanthine oxidase활성 증가율은 night phase군이 day phase군 보다 높게 나타났다. 이상 실험결과를 종합해 볼 때 요 중 hippuric acid함량이 주ㆍ야 시차에 따라 별다른 차이가 없는데도 불구하고 toluene으로부터 benzylalcohol 및 benzaldehyde 생성률이 day phase군 보다 night phase군이 높게 나타남으로서 toluene 대사산물에 의한 간 손상 정도가 day phase군 보다 night phase군이 높게 나타난 것으로 사료되어 진다.

• 미생물과산업
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• 제20권1호
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• pp.50-52
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• 1994

Coccidioides immitis의 mycelial phase와 tissue phase에 있어서 미세구조를 다음과 같은 결론을 얻었다. 1. mycelial phase의 세포구조에서는 정상적인 균이 보유하고 있는 내용물질을 관찰할 수 있었으며 이는 다른 eucaryotic cell의 구조와 같았다. 2. tissue phase에서는 mycelial phase의 세포의 크기보다 비교적 크기가 컸으며 mycelial phase에서 보다 많은 종의 vacuole이 관찰되었다. 3. Tissue phase에서는 fibril form의 내연층을 볼 수 있었다.

• 한국환경보건학회지
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• 제27권2호
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• pp.10-16
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• 2001

To evaluate an effect of circadian variation on the xylene metabolizing enzyme activities, 50% m-xylene in olive oil(0.25 $m\ell$/100g body weight) was intraperitoneally administered to the rats every other day for 6 days both in the night; 24:00 and the day; 12:00. Then animals were sacrigiced at 8hr after last injection of m-xylene. Hepatic microsomal cytochrome p450 contents were more increased both in control and xylene treated rats of night phase than those of day phase. But the activity of hepatic alcohol dehydrogenase(ADH) in control of night phase showed the similar value with that in those of day phase and xylene treated rats of day phase showed an increasing tendency of hepatic ADH activity as those of night phase showing similar activity. Furthermore, control rats of night phase than those of day phase. And by xylene treatment, enzyme activities of rats of day phase were higher tendency in rats of control but those of night phase were somewhat inhibited. Besides, xylene-treated animals of night phase showed increasing tendency of urinary methylhippuric acid concentration compared with those of day phase. On the other hand, liver weight per body weight(%), hepatic lipid peroxide content and serum xanthine oxidase activity were higher in night phase. And the activities of hepatic oxygen free radical metabolizing enzymes such as xanthine oxidase, gluthathione S-transferase, and xylene-treated rats of night phase than those of day phase. In conclusion, it can be hypothesized on the basis of the results that the accumulation rate of m-xylene intermediate metabolite, i.e. m-methylbenzaldehyde in liver tissus may be higher in night phase than in day phase and it may be responsible for higher liver toxicity in bight phase than in day phase.

• Advances in environmental research
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• 제6권3호
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• pp.189-202
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• 2017

This study examines the concentrations of particulate-phase polycyclic aromatic hydrocarbons (PAHs) and gas-phase PAHs in sidestream cigarette smoke. Sixteen PAHs were determined for four brands of cigarettes. The volume of the experimental room is approximately $66m^3$. The air samples in the room were collected before and after smoking. The median total of particulate-phase and gas-phase PAH concentrations before smoking $3.13ng/m^3$and $48.0ng/m^3$, respectively. The median concentrations of them after smoking were $10.0ng/m^3$ and $79.6ng/m^3$. The median increases in the total of 16 PAH concentrations per cigarette during smoking were 271 ng for the particulate-phase PAHs and 1960 ng for the gas-phase PAHs. According to the relationship between particulate-phase and gas-phase PAHs after smoking, the two- to four-ring gas-phase PAHs and the higher molecular weight particulate-phase PAHs were probably formed from similar precursors. The relationship between the total suspended particulate (TSP) concentration and the increase in the total particulate-phase concentration of the 16 PAHs per cigarette during smoking were significantly positive. The increase in the total gas-phase concentration of the 16 PAHs tended to increase as the TSP concentration increased. This may indicates that decreasing the amount of TSP produced inhibit the production of PAHs during smoking.

• 전기학회논문지
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• 제63권9호
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• pp.1317-1320
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• 2014

In case of using three-phase induction motor in three-phase power system, if he deficiency happens in phase among three-phase, the motor will drive in an open phase state. As to the motor, the continuing operation is possible then, but the phenomenon that the power supply stops happening by the result of the overload electricity order on the healthy phase of two phases with a damage and activating the circuit breaker. Consequently, in order to overcome this problem in treatise accordingly. I propose an uninterruptible power supply which is able to prevent that the over current on the health phase through the restoration that in case happening open phase on the power line when driving the motor. Also, it is possible to supply power consecutively without interruption of electric power and we proved the performance and reliability through an experiment.