• Journal of the Korean Society of Safety
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• v.19 no.1
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• pp.60-65
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• 2004

The PVC insulated flexible cords are used mainly as power supply cords of electric appliance. This electric wire is a stranded wire consisted of dozens of strands. In case stranded wires are disconnected by mechanical stress, it weakens electrically. Finally, the over current flows through stranded wires, and electrical fire occurs. In this study, we analyzed the melting properties of strands by over current, such as melting process, melting current and melting time. And we analyzed that quantity of heat for melting, a cross sectional structure, and surface structure by optical microscope and SEM. As analysis results, melting time decreased as melting current increased. And quantity of heat for melting was low, too. From the cross sectional structure of melted wire, when a melting current low and melting time long, it was found that the dendrite structure grew. However, the dendrite structure is hard to grow because growing time is not enough when a melting current high and melting time short.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.6
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• pp.515-520
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• 2020

The Ti₃SiC₂ MAX phase was synthesized by arc-melting process under three different processing times. We confirmed that the reaction between the TiC_X phase and Ti-Si liquid phase is important for the synthesis of the Ti₃SiC₂ MAX phase. Results suggest that the Ti₃SiC₂ MAX phase decomposed when the arc-melting time was greater than 80s. Herein, we aim to determine the detailed parameters for the reported arc-melting process, which can provide useful insights on the synthesis of the Ti₃SiC₂ MAX phase by arc-melting process. Furthermore, we compared the electrical characteristics and densities of the three samples.

• Journal of the Korean Society of Safety
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• v.38 no.2
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• pp.15-22
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• 2023

In this study, the process and the environment of a melting furnace, located in Workplace A in Chungnam Province was inspected, and the insulation resistances of electrical circuits and motors were measured, and their changes over five years (2017-2021) were analyzed. It was found that the exhaust fan, oil pumps #A and #B, and heater were installed in 2010. Their insulation resistances decreased from 2017. Specifically, the insulation resistance of Oil Pump #A decreased from 100 (㏁) in 2018 to 20(㏁) in 2021, an 80% reduction. The fast decrease in insulation resistance was due to the high temperature of the melting furnace affecting surrounding the electrical facilities. A safety management scheme on the electrical facility of the melting furnace was proposed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.167-167
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• 2010

Ge-Sb-Se계 칼코게나이드 유리의 Melting 조건변화에 따른 특성변화를 연구하였다. Glass melting 조건(homogenization-temperature, homogenization-time, annealing) 에 따라 제작된 칼코게나이드 유리 bulk를 FT-IR, XRD, SEM 등의 분석장비를 이용하여 특성을 분석하였다. Homogenization temperature가 높을수록 석영관 급냉 시 발생되는 mechanical stress와 내부응력차로 인해 칼코게나이드 유리 깨짐현상이 증가하였으며 조성비와 melting 조건에 따라 XRD분석에서 확인되지 않는 미소결정이 SEM 분석결과 관찰되었다. 본 연구를 통해 칼코게나이드 유리의 melting 조건에 따른 경향성을 확인할 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.442-446
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• 1999

Melting behavior and bridge phenomenon of solder paste, which is essential for surface mount technology in packaging, were investigated. solder paste of Sn-37%Pb was printed on Sn-coated Cu-pattern of PCB, and heated over melting point. Melting behavior of the paste was observed using CCD-camera. In order to modelize the melting and agglomeration phenomena of the paste, two solder balls of 0.76mm diameter were used. As experimental results, the paste start to melt from the margin of the printed shape. The hight of the melted paste decreased from 270 $\mu$m to 200 $\mu$m firstly, and finally recovered to 250 $\mu$m. During the melting procedure, pores were evolved from the molten paste. Bridge Phenomenon of the molten Paste depends upon the pitch of the pattern.

• Transactions on Electrical and Electronic Materials
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• v.3 no.2
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• pp.24-27
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• 2002

The NdBaCuO superconductor samples were zone-melted in low oxygen partial pressure (1%O$_2$+99%Ar). The zone-melting temperature was decreased about 12$0^{\circ}C$ film 1,06$0^{\circ}C$, the zone-melting temperature in air. Thus the loss of liquid phase (BaCuO$_2$ and CuO) was reduced during: the zone-melting process. The content of non-superconducting phase Nd422 in zone-melted NdBaCuO samples was clearly decreased and, therefore, the substitution of Nd for Ba was occurred. The superconductivity of zone-melted Nd$_{1+x}$Ba$_{2-x}$Cu$_3$O$_{y}$ prepared under low oxygen partial pressure was distinctively improved.d.d.d.

• Transactions on Electrical and Electronic Materials
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• v.4 no.1
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• pp.1-6
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• 2003

We have studied the size confinement effect on the properties of melting-like transition of small icosahedral copper clusters using a classical molecular dynamics simulation based on a well fitted empirical potential. We investigated the caloric curves of icosahedron nanoclusters and the significant depression in the melting temperatures of the copper nanoclusters was compared with that of the bulk copper. A structural transitions from decahedral to icosahedral shapes were shown. As the cluster size increased, the melting temperature increased, and the latent heat increased but seem to be saturated. However, the specific heat was unrelated to the cluster size.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04a
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• pp.14-16
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• 2002

Melting and re-solidification nature of $SmBa_2Cu_3O_{7-y}$ (Sm123) grains in Ba-Cu-O (Ba:Cu=3:5) liquid containing 0.7 at.% yttrium were investigated at the temperature lower than its melt point. When Sm123 grains/liquid powder compacts were heated to a temperature between two melting points of Ba-Cu-O liquid ($1000^{\circ}C$) and a Sm123 phase ($1060^{\circ}C$) and held at this temperature for appropriate time, Sm123 grains melted partly in the liquid that was formed by melting of the liquid-forming powder. During subsequent slow cooling, (Sm,Y)$Ba_2Cu_3O_{7-y}$ solidified at the outer parts of the unmelted Sm12 grains, which is distinguished from the core regions by lower $Sm_2BaCuO_5$ (211) density.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.356-359
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• 1997

The Effects of different melting temperature and holding time in the melting temperature on J$\sub$c/ of YBa$_2$Cu$_3$O$\sub$x/ based superconducting bulk using MPMG process were investigated. the value of critical current density was the largest at l120$^{\circ}C$, the melting temperature which is appointed to the mid point of (Y$_2$BaCuO$\sub$5/ + Liquid)region. With the melting temperature in which the value of J$\sub$c/ is the largest, J$\sub$c/ was again measured to see whether the holding time at this proper melting temperature has the effect on the critical characteristics. From the result above it was concluded that the melting temperature and holding time were important to improve the J$\sub$c/ and the formation of the Y$_2$BaCuO$\sub$5/. In this paper, the melting temperature obtained was l120$^{\circ}C$ and propel holding time could be obtained as 20 minute and the more holding time was not effective in the J$\sub$c/ improvement as well as the formation of Y$_2$BaCuO$\sub$5/.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1775-1777
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• 2009

BiSrCaCuO films were prepared on MgO single substerate at $885^{\circ}C$ by melt process. The films showed superconductivity above liquid nitrogen temperature (Tc= 96K). To investigate the effect of a melting temperature on the forming of the surface texturing, the samples were prepared under various temperature. The used powder was of high Tc phase. It is implies that the origin of the properties due to the heat treatment.