• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 춘계학술대회 논문집
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• pp.590-596
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• 2002

Contact wires are made by metallic materials and exposured at atmosphere. We have investigated mechanical properties and the present condition of air pollution as to the messenger wires and ACSR wires of these contact wires. Mechanical properties between new contact wires and used, the used one's tensile strength and elongations was decreased by effect from corrosion. We observed a fatigue properties which was investigated by fatigue test because contact wires were affected with amplitude vibration everytime the train passed through the railways. In the evaluation of fatigue test, it was also shown that fatigue life of the used wires was decreased 50 ∼ 60% compared with that of new ones in average by effect from corrosion.

• 한국초전도ㆍ저온공학회논문지
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• 제8권2호
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• pp.33-36
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• 2006

Multi-stacked HTS wires are needed to conduct large current in the power application. In this paper, magnetization losses of the multi-stacked YBCO wire and the BSCCO wire have been measured and compared. 4 types of YBCO wires and BSCCO wires, that is, single, 2-stacked, 3-stacked and 4-stacked, have been tested. HTS multi-stacked wires were fabricated using face-to-face type stacking method. Measurements of magnetization loss were performed under various angles of external magnetic field to consider the anisotropic characteristics of HTS wires. The ratios of the magnetization loss by multiple stacking of superconducting wires were presented. Measurements results show that loss reduction ratios have three distinct regions due to the magnitude of external magnetic field, the material of HTS wire and number of stacks.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.495-498
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• 2004

In this paper, the arc and flame characteristics of wires were studied during a short-circuit. The short-circuit angle between wires was fixed as $90^{\circ}$ and the experiments were conducted on bare copper wires by varying the diameter of wires. The arc and flame patterns were taken by a high speed imaging system. The direction of arc and flame was explained with Lorentz force. After the short-circuit experiment, the shapes of molten wires were analyzed by a stereo microscope. In the results of experiment, the arc and flame of wires showed particular patterns. The flame characteristics by the diameter of wires were analyzed using a HSIS. We could find out the arc characteristics of wires which were different by the diameter.

• 대한치과교정학회지
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• 제22권3호
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• pp.591-602
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• 1992

The purpose of this study was to evaluate the effect of heat treatment on physical properties of 0.016' and 0.016' x 0.022' stainless steel wires. Temperature of heat treatment had intervals of $50^{\circ}C$ from $400^{\circ}C$ to $700^{\circ}C$, and time of heat treatment were 3, 6 and 9 minutes. Tensile tests were measured by ultimate tensile strength and yield strength. Bending tests were assessed by maximum bending force, recovery force, and stiffness. Torsion test was evaluated by torsion cycle until wires were fractured. The results were as follows: 1. In round wires, the highest value of ultimate tensile strength and yield strength were recorded of heat treatment at $500^{\circ}C$. In rectangular wires, the highest value of ultimate tensile strength were after 9 minutes at $400^{\circ}C,\;450^{\circ}C$ and 3, 6 minutes of heat treatment at $50^{\circ}C$, yield strength were the highest value after 3, 6 minutes of heat treatment at $500^{\circ}C$. 2. In both round and rectangular wires, maximum bending force and recovery force were the highest values after 6 minutes of heat treatment at $500^{\circ}C$. In round wires, highest value of stiffness were formed after 9 minutes at heat treatment at $500^{\circ}C$. In rectangular wires, the highest value of stiffness were for 6 minutes in $500^{\circ}C$. 3. In rectangular wires, torsion cycle was minimum after 6 minutes of heat treatment at $500^{\circ}C$. 4. In all of tension, bending, and torsion tests, the heat treated wires were softened over at $700^{\circ}C$. 5. In all of tension, bending, and torsion tests, physical properties of the wires were more influenced by the temperatures than the duration of the heat treatment.

• 한국철도학회논문집
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• 제5권1호
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• pp.32-39
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• 2002

As most railways are gradually electrified with modernized electric cars, the demand for catenary wires and their facilities are also increased. Catenary Wires are exposed to the marine area with air-borne salt or severely polluted industrial area with much corrosive emission gases depending on the locations. Corrosion of catenaty wires can make their actual lifetime shorter than that originally designed. Thus, the messenger and ACSR wires, kinds of catenary wire system, were investigated with respect to corrosion, which include new and used ones collected at the field. Tensile strengths and elongations appeared to decrease when the wires were exposed to corrosive environments. The amount of decrease was more prominent as environmental conditions became more corrosive. They are also vibrated with some amplitude everytime pentographs touch contact line. The frequent cyclic load on the wire may result in a fatigue damage. Surface damage by corrosion can make fatigue crack initiate with ease. In the present study, the fatigue life of the used wire was measured 50 to 60% compared with that of new one in average.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.214-214
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• 2009

While critical properties of BSCCO wires rely considerably on grid direction upon BSCCO and have very complicated mechanism of generating a superconducting phase, making it difficult to improve properties of wires, YBCO thin-film wires which can be formed in a superconducting phase upon metal board through vapor deposition processing can get excellent direction and reduce manufacturing costs with more flexibility in improving critical properties; thus, they will be suitable for instrument application in the future. Contrary to BSCCO wires for which thick silver alloy covering materials should inevitably be used, moreover, YBCO thin-film wires have an advantage of making thickness and quality of covering materials different by usage. Such a property can be an important element to widen application of wires by presenting possibility of using thin-film wires as superconducting material for fault current limiter as well as for high power current application. In this study we intend to prepare YBCO thin-film wires with different stabilizer layers to analyze current application and current restriction properties by stabilizer layers on the basis of detailed researches on changes in current classification properties below critical value.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.175-175
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• 1999

Circumventing problems lying in the conventional lithographic techniques, we devised a new method for the fabrication of nanometer scale metal wires inspired by the unique characteristics of carbon nanotubes (CNTs). Since carbon nanotubes could act as masks when CNT-coated thin Au/Ti layer on a SiO2 surface was physically etched by low energy argon ion bombardment 9ion milling), Au/Ti nano-wires were successfully formed just below the CNTs exactly duplicating their lateral shapes. Cross-sectional analysis by transmission electron microscopy revealed that the edge of the metal wire was very sharply developed indicating the great difference in the milling rates between the CNTs and the metal layer as well as the good directionality of the ion milling. We could easily find a few nanometer-wide Au/Ti wires among the wires of various width. After the formation of nano-wires, the CNTs could be pushed away from the metal nano-wire by atomic force microscopy, The lateral force for the removal of the CNTs are dependent upon the width and shape of the wires. Resistance of the metal nano-wires without the CNTs was also measured through the micro-contacts definted by electron beam lithography. since this CNT-based lithographic technique is, in principle, applicable to any kinds of materials, it can be very useful in exploring the fields of nano-science and technology, especially when it is combines with the CNT manipulation techniques.

• Journal of the Korean Wood Science and Technology
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• 제18권4호
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• pp.9-17
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• 1990

When manufacturing beam by laminating particleboards, the mechanical properties of particleboad-laminated beam would be also improved if the properties, especially mechanical properties of particleboad be reinforced. In this study, steel wires were used to reinforce particleboard. This study was carried out to obtain the basic mechanical properties of the board composed of wood particle and steel wires, focusing on bending strength which is the important factors in laminated beam and it was tried to estimate the relationship between the properties of the particleboard-laminated beam. and the proportion of steel wires to wood particles in particleboards. The result obtained can be summarized as follows: 1. The more steel wires used in boards, the higher value of modulus of rupture in bending was obtained, For example. the density 5 board composed of 14 numbers of steel wires showing 55% improved value than control board. 2. The board with lower density was also made better in higher value of elasticity, the density 0.5 board with 14 numbers of steel wires improved by 170%, the density 0.6 board by 86%, the 0.7 board by 37% and the 0.8 board by 26%. 3. The work to maximum load was improved with more steel wires. for example, the density 0.8 board with 14 numbers of steel wires improved by 31%.

• 한국분무공학회지
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• 제26권3호
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• pp.149-156
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• 2021

In this study, the behavior of the droplet colliding with parallel wires was analyzed by time-delay photography. The impact behavior modes and the critical capture speed were analyzed by changing fluids, the droplet velocity, the wire diameter and the distance between wires. Seven typical modes of impacting droplet on parallel wires were observed. The tendency of mode change was generally similar when the wire diameter was changed, but the increase of the wire diameter caused the increase of the droplet velocity at which the mode changed. The modes at the highest droplet velocity were the splitting mode when the wires were closest, the passing and splitting mode in the middle, and the passing mode when the wires were farthest apart. The critical capture speed increased as the wire diameter increased and the distance between wires decreased. The ethanol droplet showed the lowest critical capture speed.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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• pp.27-34
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• 2000

HTS wires processed by PIT method are now available for magnet applications. But, those wires can not be used over 40 K due to weak link. This leads to necessity of development of coated conductor which can retain high $J_c$ at high field in liquid nitrogen. In this paper, various technical issues and the R&D status for both PIT wires and coated conductor were discussed. The difference of coated conductor's processes were also investigated and summarized. Various requirements for a design of HTS magnets were discussed. Anisostropic $J_c$ property with respect to magnetic field was considered to determine the coil's critical current. Low n value is a critical parameter to degrade a field stability with respect to time for a persistent mode HTS magnet. The relation between the margin of operation current and n value was investigated. Prototype HTS magnets with PIT wires are being developed for various applications such as crystal growth, MRI, magnetic separator and etc. HTS magnets will come into wide use in various fields of industries if the HTS wires with a low performance cost is developed.