• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.04a
• /
• pp.16-21
• /
• 2002

Generally, Oxidization film are generated by friction and wear in lubricant oil. It is effect that the heat and pressure act on contact area. Because the electrons movement progress the oxidization, if the electrons movement be regulated, the thickness of oxidization film can be regulated and friction characteristics can be improved. But electronic current can deteriorate friction characteristics, so various characteristics must be investigated on transforming of electronic current. Therefor, using the Norton equation, short current were transformed between ball and disk. Also, an experiment was carried out using ball on disk type tester. So, we studied up on effect of current for friction characteristics.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.05a
• /
• pp.150-155
• /
• 2002

Generally, Oxidization film are generated by friction and wear in lubricant oil. It is effect that the heat and pressure act on contact area. Because the electrons movement progress the oxidization, if the electrons movement be regulated, the thickness of oxidization film can be regulated and friction characteristics can be improved. But electronic current can deteriorate friction characteristics, so various characteristics must be investigated on transforming of electronic current. Therefor, using the Norton equation, short current were transformed between ball and disk. Also, an experiment was carried out using ball on disk type tester. So, we studied up on effect of current for friction characteristics.

• Tribology and Lubricants
• /
• v.18 no.5
• /
• pp.339-344
• /
• 2002

Whenever moving surfaces of machine driving elements interact in air and lubricating oil, oxidization film on the surfaces are generated. It is effect to prevent friction and wear on contact area. Since the electronic current progress the oxidization of metal, if the electronic flow be regulated, the thickness of oxidization film can be regulated and friction characteristics can be improved. But the electronic current can deteriorate friction characteristics, so various characteristics must be investigated on transforming of electronic current. Therefor, using the Norton equation in this study, short current were transformed between frictional materials using ball on disk type tester. It was studied on effect of electronic current for friction characteristics.

• Journal of the Korean Ceramic Society
• /
• v.46 no.3
• /
• pp.330-335
• /
• 2009

We investigated the effects of the re-oxidation temperature and time on the positive temperature coefficient (PTC) of resistivity characteristics of Sm-doped $BaTiO_3$ sintered at $1200{\sim}1260^{\circ}C$ for 2 h in a reducing atmosphere (3% $H_2/N_2$), followed by re-oxidization processes in air, in which re-oxidization temperature and time were $600{\sim}1000^{\circ}C$ and $1{\sim}10$h, respectively. The result reveals that Smdoped (Ba,Ca)$TiO_3$ ceramics fired in a reducing atmosphere exhibit low PTC characteristics, whereas the sample re-oxidized at $800^{\circ}C$ for 1 h in air exhibit pronounced PTC characteristics. The room-temperature resistivity and jumping characteristics of resistivity (${\rho}_{max}/{\rho}25^{\circ}C$) decrease with Sm contents. The PTC characteristics with reoxidization time at $800^{\circ}C$ have improved about $2{\sim}3$ orders of magnitude whereas differed according to the sintering temperature. The 0.7 at% Sm-doped (Ba,Ca)$TiO_3$ samples reveal the best PTC characteristics in the present range of formula and processes.

• Journal of Technologic Dentistry
• /
• v.30 no.1
• /
• pp.65-71
• /
• 2008

The use of titanium in the field of dentistry has increased, due to their excellent biocompatibility, appropriate mechanical properties, corrosion-resistance and low price. However, many difficulties with the use of titanium for metal-ceramic crowns remain to be solved. The objective of this study was to evaluate the influence of surface modifications on the bonding characteristics of specific titanium porcelain bonded to cast titanium. The surfaces of Titanium were prepared with 4 test groups, i) sandblasted with particles of different size, ii) sandblasted after treated oxidization and oxidized after sandblast. We observed the bond strength and node aspect of titanium and ceramic, and respect to the methods of modifying surface of titanium by the test of mean roughness of surface, Scanning Electron Microscope, and 3-point flexural bend test. The results show that, 1. The specimens, which treated oxidization after process of sandblast with particles of 50um size, were the better for the bond strength in comparison with other specimen. 2. The specimen with process of sandblasting after oxidization treatment were the better for stability of the bond strength. 3. The wettability of titanium surface affect the bond strength.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.07a
• /
• pp.576-577
• /
• 2005

In this paper, the oxidization characteristics were analyzed according to the shapes of Residual Current Protective Device(RCD) contacts. RCD is an electrical safety device specially designed to immediately switch the electricity off when electric leakage is detected at a level harmful to a person using electrical equipment. The shapes of RCD contacts are a little bit different according to the models. When RCD is turned on, stationary and moving contact do not fit together. So, it can cause the increase of contact resistance. To discover the deterioration characteristics of RCD contacts by switching repetition, the contacts were analyzed by stereo microscope, Scanning Electron Microscope(SEM) and Energy Dispersive X-ray Spectrometer(EDS).

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.23 no.3
• /
• pp.330-341
• /
• 1999

An experimental study for the two types of burners used in the non-oxidizing direct fired furnaces of the heat treatment process for the cold rolled plate has been carried out to investigate the combustion characteristics and the oxidization of the surface of steel plate. A steep temperature gradient and entrainment of residual oxygen were found near the heating surface in the flame of the nozzle mixing burner which has strong swirl velocity component. It was concluded that the elimination of the residual oxygen and the increase of the temperature of combustion gas on the heating surface are needed to enhance the performance of the burners for application to the non-oxidizing direct fired furnaces.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.10a
• /
• pp.83-88
• /
• 2004

Micro wires manufactured by the straightening progress are widely used in bio-medical and semi-conductor fields. In this study, we have developed a novel straightener which uses the direct heating method for straightening. In order to avoid the surface oxidization, during the heating process, we supplied the inert gas(Ar) and examined the effect of the gas flow rate. The effect of the tension and the current applied to the tungsten micro wires were thoroughly studied. From various experiments, it was found that when the tension is $500{\sim}600gf$ and the current is about 1.5A, we obtained higher straightness(${\approx}1{\mu}m/1000{\mu}m$) and roundness ($<{\pm}2{\mu}m/100{\mu}m$).

• Proceedings of the SCSK Conference
• /
• 2003.09b
• /
• pp.139-144
• /
• 2003

Using GC/MS and GC/Olfactmetry analysis, we identified two vinyl ketones such as 1-Octen-3-one (OEO) and cis-1, 5-Octadien-3-one (ODO) as key materials in axillary odor. OEO and ODO showed a strong metallic odor and low odor threshold. These two materials were occurred from the reaction of unsaturated long fatty acids in lipids and the iron ion in our body's metabolism. Then, it was recognized that Morus alba (Japanese name, Kuwa) extract, one of the plant extract, showed a very good effect to control the generation of these vinyl ketones due to its remarkable anti-oxidization effects.

• Journal of Environmental Science International
• /
• v.24 no.8
• /
• pp.1015-1021
• /
• 2015

In order to establish the design parameters of adsorption for arsenic compounds with hydrotalcite including chlorine ion, the basic properties of adsorption and desorption as well as the oxidation of As (III) were examined in batch tests. The maximum adsorption capacities of arsenite and arsenate were 6.2 mg-As(III)/g and 103 mg-As (V)/g, respectively. Although 80.4% of maximum desorption was shown in 20% NaOH solution, 5~10% of NaOH was recommended considering operating benefits, where the proper condition of the desorption was in the range of 73% to 80%. The most suitable desorption condition was in the combination of NaCl (10~20%) and NaOH (5~10%). Within 2 minutes, As (III) was easily oxidized to As (V) with 0.0001 N KMnO4, where the maximum oxidization ratio was shown to 98.9%.