• 한국초전도ㆍ저온공학회논문지
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• 제15권4호
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• pp.39-43
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• 2013

To reduce the magnetization loss of a coated conductor, the striation and the transposition have to be accomplished for magnetic decoupling. The loss reduction effect in incomplete as well as complete striated YBCO CCs was reported in previous research. At the case of the incomplete striated sample, the end region of the sample is non-striated. So, it is not jointed with each other. In power applications, the joint is needed because current leads must be connected with HTS coils. In this research, the influence of end-joint methods with copper and superconducting joint on magnetization loss in striated YBCO CC and spiral winding samples are presented and compared with non-striated measured result.

• 한국염색가공학회지
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• 제18권6호
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• pp.25-30
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• 2006

Degumming is an essential process to improve the luster and smoothness of the silk filament. Silk varieties were degummed using different methods. A number of methods, from pad-steam to specific alkaline are being used for this propose. In this paper an attempt to compare the efficiencies of different degumming processes has been made. from the results, it may be observed that when silk fabrics were pad-steam, the degree of degumming, as assessed by weight loss. When the pad-steam degumming was carried out at different pHs, adjusted using alkalies, it was observed that at higher pH the weight loss is high. Pad-steam degumming as well as star degumming was found to be superior with minimum damage to the substrate. Among the alkalis used, the sodium carbonate gives the best results, since the weight loss is almost maximum with lower strength loss by over degumming. It is also efficient from the point of view of conservation of heat energy and time as against the comparable star degumming.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.49-51
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• 2004

The iron loss in electric machines takes large part of machine losses and the reduction of iron loss brings the increase of the efficiency. In the rotating machines, however it is very difficult to calculate the iron loss and to get the exact experiment result because the measuring precesses are very complex and laborious. As is well known, the relation between the flux density B and the magnetic field intensity H relation is not linear. For the iron loss, B and H must be measured and usually B becomes the reference wave(sine wave) and the following H is measured using H-coil. To make the B as sine wave, B is controlled by some devices. The error is controlled to become zero by the proposed algorithm which uses the bisection algorithm. The experiments are compared with the simulation results, and they show acceptable agreements.

• 산업경영시스템학회지
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• 제18권34호
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• pp.61-67
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• 1995

Through the model presented in this paper, we study on the depletion of stock taking place due to random loss of items as well as random demand, under the assumption that the distributions of demand are independent of those of loss, and both of them are identical, and that life time distribution of each item is negative exponential. The steady state probability distribution of the stock level assuming instantaneous delivery of order under (s, S) inventory policy. Also we have derived total expected cost expression with loss cost. The results of sensitive analysis show that the effect of loss rate is substantial on the total cost and optimal value of inventory level.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 추계학술대회 논문집
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• pp.260-262
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• 2003

AC loss is an important issue in the design of high-T$_{c}$, superconducting power cables which consist of a number of Bi-2223 tapes wound on a cylindrical former. In this paper, the ac loss characteristics in the 3-conductor have investigated experimentally. The loss test results indicate that the ac loss is not related to the arrangement of Bi-2223 tapes, contact position and applied frequency. The measured losses in face-to-face arrangement are larger than those in edge-to-edge arrangement. The measured losses in the 3-conductor also agree well with the sum of the transport losses measured in each Bi-2223 tape.e.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1969-1974
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• 2004

The performance of small cyclone is analysed by an experiment for the purpose of developing a bag-less vacuum cleaner. For the high collection efficiency and low pressure loss cyclone, the effect of cyclone inlet feature must be well understood. Four types of the helical inlet are considered to compare with the normal tangential inlet, and also various inlet velocities are used to each inlet type. Based on the reference dimension, each type of inlet shows the changes of the grade efficiency and pressure loss which determine the cyclone quality. The results show that the helical inlet has the smaller cut-size but bigger pressure loss than the tangential inlet. And the degree of opening area influences factors of cyclone performance. As the inlet velocity is increased, the cut-size becomes smaller and the pressure loss becomes bigger of each cyclone. Further studies are required to understand the optimized helical inlet of cyclone.

• Journal of Magnetics
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• 제20권2호
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• pp.138-147
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• 2015

The unique nano-scale inter-lamellar microstructure and unparalleled heat treatment process give our developed metal powder composite its outstanding magnetic property for power inductor & motor applications. Compared to the conventional polycrystalline Fe or amorphous Fe-Cr-Si-B alloys, our unique designed inter-lamellar microstructure strongly decreases the intra-particle eddy current loss at high frequencies by blocking the mutual eddy currents. The combination of optimum permeability, magnetic flux and extremely low core loss makes this powder composite suitable for high frequency applications well above 10 MHz. Moreover, it can be also possible to SMC core for high speed motor applications in order to increase the motor efficiency by decreasing the core loss.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권11호
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• pp.658-663
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• 2004

According to the improvement of the HTS wires performance, several tapes of HTS superconducting machines are being developed. Stacked HTS tapes are used as conductor that can flow high current for the HTS power machines. To develop the HTS power machines, the critical current characteristics of a stacked HTS tapes in external filed and AC losses should be examined. In this paper, we present characteristic of the stacked HTS tapes and AC losses of HTS pancake windings with stacked tapes. AC loss of the pancake winding were measured and compared with the calculated loss by using AC loss data of the stacked samples and the magnetic flux density in the HTS winding under operating conditions. We can see that measured results generally agree well with the calculated results by using AC loss data of 4-stacked sample.

• Journal of Electrical Engineering and Technology
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• 제2권2호
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• pp.194-200
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• 2007

The deregulation problem has recently attracted attentions in a competitive electric power market, where the cost must be earmarked fairly and precisely for the customers and the Independent Power Producers (IPPs) as well. Transmission loss is an one of several important factors that determines power transmission cost. Because the cost caused by transmission losses is about $3{\sim}5%$, it is important to allocate transmission losses into each bus in a power system. This paper presents the new algorithm to allocate transmission losses based on an integration method using the loss sensitivity. It provides the buswise incremental transmission losses through the calculation of load ratios considering the transaction strategy of an overall system. The performance of the proposed algorithm is evaluated by the case studies carried out on the WSCC 9-bus and IEEE 14-bus systems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1225-1227
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• 2005

A Bi-2223 tape has beer developed for power applications such as a fault current limiter, a power cable and a superconducting magnetic energy storage system. In such applications, the Bi-2223 tape carries time varying transport current and in addition experiences time varying external magnetic field. It is well known that the external magnetic field not only causes magnetization loss in the Bi-2223 tape, but also drastically increases transport loss due to a so-called "dynamic resistance". We developed an evaluation setup, which can measure transport loss in external at magnetic fields. Using this equipment, we measured the dynamic resistances for various amplitudes and frequencies of an external ac magnetic field perpendicular to the face in the tape. Simultaneously we investigated the effect of an external ac field on transport loss with different experimental conditions. This paper describes test results and discussions on correlation between the dynamic resistance and the transport loss for the Bi-2223 tape.