• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.3
• /
• pp.174-180
• /
• 1998

In this work, the properties of FRP, which is applied recently in the composite insulating materials, by thermal treatment were investigated. The specimens were epoxy glass laminates fabricated by thermal press method and had the volume content of 46[%] cutted $45^{\circ}C$ in the fiber direction and 1.0[mm] thickness. The experimental results showed that the amount of weight loss, wettability, surface potential, and surface resistivity increased up to 200[$^{\circ}C$] as a function of temperature. Usually, most degradations caused the hydrophilic to decrease the contact angle. But, in this work on thermal-degradated FRP, we can confirm the introduction of hydrophobic properties by cross-linking and the ablation of polar small-molecules rather than chain scission and oxidation. Finally, weight loss and contact angle increased. These phenomena show the existence of hydrophobic surface. With the change to the hydrophobic surface and the electrical potential and resistivity on FRP surface increased. But, the dielectric properties and tensile stength are decreased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07a
• /
• pp.334-337
• /
• 2002

The Quantum Hall Resistance(QHR) device which consists of GaAs/AlGaAs heterojunction structure is used for the realization of QHR Standard based on QHE. In order to characterize electrical contact resistances and dissipations of the device, it is slowly cooled down for eliminating thermal shock and unwanted noise. Then, the two properties are measured under 1.5 K and 5.15 T. Contact resistances are all within 1.2 Ω and longitudinal resistivities are all within 1 mΩ up to DC 90${\mu}$A. The results mean the device is operated well to realize the QHR Standard. To confirm it, the QHR Standard having the device is compared using a direct current comparator bridge with a 1 Ω resistance standard which the calibrated value is known from QHR standards maintained by other countries. The difference between them is agreed well within measurement uncertainty. It is thus considered that the properties of the device is estimated well and has good performance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.22 no.9
• /
• pp.717-723
• /
• 2009

Ni/Al ('/' denotes deposition sequence) contacts were deposited on Al-implanted 4H-SiC for ohmic contact formation, and the conduction properties were characterized and compared with those of Ni-only contacts. The thicknesses of the Ni and Al thin film were 30 nm and 300 nm, respectively, and the films were sequentially deposited bye-beam evaporation without vacuum breaking. Rapid thermal anneal (RTA) temperature was varied as follows : $840^{\circ}C$, $890^{\circ}C$, and $940^{\circ}C$. The specific contact resistivity of the Ni contact was about $^{\sim}2\;{\pm}\;10^{-2}\;{\Omega}{\cdot}cm^2$, However, with the addition of Al overlayer, the specific contact resistivity decreased to about $^{\sim}2\;{\pm}\;10^{-4}\;{\Omega}{\cdot}cm^2$, almost irrespective of RTA temperature. X-ray diffraction (XRD) analysis of the Ni contact confirmed the existence of various Ni silicide phases, while the results of Ni/Al contact samples revealed that Al-contaning phases such as $Al_3Ni$, $Al_3Ni_2$, $Al_4Ni_3$, and $Ab_{3.21}Si_{0.47}$ were additionally formed as well as the Ni silicide phases. Energy dispersive spectroscopy (EDS) spectrum showed interfacial reaction zone mainly consisting of Al and Si at the contact interface, and it was also shown that considerable amounts of Si and C have diffused toward the surface. This indicates that contact resistance lowering of the Ni/Al contacts is related with the formation of the formation of interfacial reaction zone containing Al and Si. From these results, possible mechanisms of contact resistance lowering by the addition of Al were discussed.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.8
• /
• pp.2277-2280
• /
• 2014

The contact properties between gold and poly(3-hexylthiophene) (P3HT) films having either of two distinct molecular orientations and orderings were investigated. Thermal treatment increased the molecular ordering of P3HT and remarkably reduced the contact resistance at the electrode/semiconductor interface, which enhanced the electrical performance. This phenomenon was understood in terms of a small degree of metal penetration into the P3HT film as a result of the thermal treatment, which formed a sharp interface at the contact interface between the gold electrode and the organic semiconductor.

• Proceedings of the KSR Conference
• /
• 1999.05a
• /
• pp.176-184
• /
• 1999

Dynamic characteristics of pantograph-catenary system that supplies electrical power to high-speed trains are investigated. A simple catenary is composed of the contact and messenger wires connected by hamgers possessing bi-directional stiffness properties. The influences of parameters that determine the contact properties of pantograph-catenary system are investigated through numerical simulations. For the catenary, a finite difference model composed of 10 spans is constructed. The contact and messenger wires are modeled as strings with respective tension and damping ratio values. The pantograph is modeled as a linear 3-degree-of-freedom system. It is found that the tension, number of hangers and damping ratios as well as the speed of the train significantly influence the contact forces and contact separation rate

• Proceedings of the KIEE Conference
• /
• 2007.10c
• /
• pp.209-210
• /
• 2007

This paper describes the various wavelengths of electrical arc on overhead contact line for improvement of the current collection performance. The tests are performed with the arc measuring device and a welding machine to generate electrical are artificially. The experimental result shows the electrical are on overhead contact line and pantograph could be analyzed by artificial discharge.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1999.11a
• /
• pp.87-87
• /
• 1999

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.48 no.2
• /
• pp.86-91
• /
• 1999

In order to analyse the degradation process of epoxy/glass fiber for outdoor condition, FRP laminate was exposed to the wavelength of ultraviolet rays and evaluated by comparing contact angle, surface resistivity, surface potential decay, and ESCA spectrum respectively. As irradiation energy are increased, the surface properties were steeply decreased in the range of 300[nm]. But the measured values within the scope of400[nm]∼440[nm] showed a increase as compared with the untreated ones. Also, fromthe result of ESCA spectrum, it was confirmed plenty of oxygen groups on the spot showing the maximum decrease of surface properties and the existence of ether groups on the surface of coloring phase. We can conclude that the degradation phenomena on the surface of epoxy composites are dominated by the induction of ester and carboxyl groups.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.11a
• /
• pp.57-60
• /
• 2000

In this paper, study on the properties of the thermal degradated epoxy resin which is used in indoor insulation apparatus is performed to investigate the problems of the decreasing insulation characteristics and crack in the indoor insulation apparatus. As a parameter of variation, SEM, contact angle, surface resistivity, relative dielectric constant and weight loss are measured. As the results of the above measurements, the contact angle and surface resistivity of the epoxy resin has increased to 200$^{\circ}C$ in but at the above 200$^{\circ}C$ the values have decreased. The relative dielectric constants the thermal treated samples have increased on with the temperature increase. We find the volatile components of the epoxy resin compound has disappeared during thermal degradation by SEM. The insulation properties of the epoxy resin have increased by the 200$^{\circ}C$ but decreased in the above 200$^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.16 no.11
• /
• pp.1001-1007
• /
• 2003

The silicone fluids have been generally used as processing agent in silicone rubber(SIR) compounding. The addition of hydroxy silicone (HS) fluids to SIR for insulator housing material is required to meet the good electrical performance and the good processability. In this study, SIR with HS fluids was evaluated to investigate how the kinds of them affect insulation properties. The contact angle of the virgin sample of 40-HS SIR was low and its recovery rate was also slow. The recovery rate of 50-HS SIR was the highest being decreased with the viscosity increase of HS fluids. The tracking resistances and the corona aging resistance of 70-HS SIR and 1,040-HS SIR were excellent Tracking resistance depended largely on heat resistance of silicone fluids. But arc resistance didn't depend merely on the kind of silicone fluids.