• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2002.10b
• /
• pp.315-316
• /
• 2002

Electrochemical discharge machining is a very recent technique for non-conducting materials such as ceramics and glasses. ECDM is conducted in the NaOH solution and the cathode electrode is separated from the solution by $H_2$ gas bubble. Then the discharge is appeared and the non-conductive material is removed by spark and some chemical reactions. In the ECDM technology, the $H_2$ bubble control is the most important factor to stabilize the discharging condition. In this paper, we proposed the discharge peak monitoring/ discharging duty feedback algorithms for the discharge stabilization and the feasibility of this algorithm is verified by various pattern machining in the constant preload conditions for the cathode electrode.

• KSTLE International Journal
• /
• v.3 no.2
• /
• pp.95-100
• /
• 2002

Electrochemical discharge machining is a very recent technique for non-conducting materials such as ceramics and glasses. ECDM is conducted in the NaOH solution and the cathode electrode is separated from the solution by H$_2$ gas bubble. Then the discharge is appeared and the non-conductive material is removed by spark and some chemical reactions. In the ECDM technology, the H$_2$ bubble control is the most important factor to stabilize the discharging condition. In this paper we proposed the discharge peak monitoring/discharging duty feedback algorithms fur the discharge stabilization and the feasibility of this algorithm is verified by various pattern machining in the constant preload conditions for the cathode electrode.

• Proceedings of the KIEE Conference
• /
• 1991.07a
• /
• pp.3-12
• /
• 1991

Fuel cells are electrochemical devices that convert the chemical reaction energy directly into the electrical energy. In a typical fuel cell, gaseous fuel is fed continuously to the anode(negative electrode) compartment and the oxidant(i.e, oxygen from air) is fed continuously to the cathode(positive electrode) compartment; the electrochemical reactions take place at the electrodes to produce an electric current. Many of the operational characteristics of fuel cell systems are superior to those of conventional power generation system because of good efficiency, environmental protection, safty, modularity etc. From those reasons, the fuel cells are considered to be the solution to the future problem of energy conversion. The objective of this paper is to introduce the technical status of fuel cell technologies and our national project for the development of the phosporic acid fuel cell.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.12C no.4
• /
• pp.214-219
• /
• 2002

The influence of ultraviolet (UV) irradiation and corona on the surface degradation of high temperature vulcanized (HTV) silicone rubber used for outdoor insulation through measuring surface voltage decay after corona charging, surface resistivity, contact angle and X-ray photoelectron spectroscopy (XPS) analysis was studied. The surface resistivity calculated by the surface voltage decay was compared with a value directly obtained from the three electrode method having the guard ring electrode. A good agreement between the two methods for surface resistivity was obtained. UV treated specimens showed the slower decrease of surface voltage decay, while the corona exposed specimens showed a dramatically faster decrease. Although both artificial treatments cause the same oxidative products, which was confirmed with XPS, we could distinguish the difference between the reactions of the two treatments by monitoring the surface voltage decay on corona-charged specimen. In addition, we could derive the specific surface states of the silicone rubber treated by accelerated artificial aging factors and the degradation process.

• Journal of Veterinary Clinics
• /
• v.16 no.2
• /
• pp.413-416
• /
• 1999

To establish feline electroacupuncture anesthesia, 5 cats (mixed, 1 month old, 0.4~0.5 kg, female) were examined in the present study. The acupoints used for feline electroacupuncture anesthesia were Tian-ping and Bai-hui. After perpendicular insertion of needle to Tian-ping and Bai-hui, respectively, positive electrode was connected at Tian-ping and negative electrode was connected at Bai-hui, respectively, Electric condition was 3 V and 30 Hz. To examine the effect of electroacupuncture anesthesia, laparotomy (5 heads)was applied. The pain of the body surface and the extremities excluding the tail was not found, and the induction time of electroacupuncture anesthesia was approximately 1 minute. As for the reactions with electroacupuncture anesthesia, the head part was directed to backward, blepharoreaction was mild and the consciousness was vivid. The class of anesthesia effect was excellent in 4 heads and was poor in 1 head. The pain was not observed and bleeding was comparatively small volume during surgery in excellent group.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.12
• /
• pp.83-89
• /
• 1996

The electrochemical spike oscillations at the nickel (Ni) electrode/(0.05M KHC$_{8}$H$_{4}$O$_{4}$) buffer solution (pH 9) interface have been studied using voltammetric and chronoamperometric methods. The nature of the periodic cathodic current spikes is the activation controlled currents due to the hydrogen evolution reaction and depends onthe fractioanl surface coverage of the adsorbed hydrogen intermediate or the cathodic potential. There is two kinds of the waveforms corresponding to two kinds of the cathodic current spike oscillations. The widths, periods, and amplitudes of the cathodic current spikes are 4 ms or 5ms, 151 ms or 302 ms, and < 30 mA or < 275 mA, respectively. The fast discharge and recombination reaction steps are 1.5 times and twice and faster than the slow discharge and recombination reaction steps. The fast and slow discharge and recombination reaction steps are 1.5 times and twice faster than the slow discharge and recombination reaction steps. The fast and slow discharge and recombination reactions corresponding to the fast and slow adsorption sites at the Ni cathode.

• Journal of the Korean Ceramic Society
• /
• v.21 no.1
• /
• pp.60-66
• /
• 1984

During the metallization in the manufacturing of the ceramic capacitor at the boundary layer between Pd or Pt electrode and $BaTiO_3$-dielectric reactions were analysed. For the study of the reaction Electron Spin Resonance (ESR) Method was used. With the aid of ESR an increased of the concentration of the paramagnetic $Ti^{3+}$-Centers on the metallizing process could be seen. It meaned a reduction effect although the metallization was accomplished under oxidation atmosphere. Therefore it could be regarded as a reaction at the boundary layer. In order to investigate the reaction ad double octahedral model was compared and the increase of the $Ti^{3+}$-concentration was studied.

• Journal of the Korean Electrochemical Society
• /
• v.10 no.3
• /
• pp.203-206
• /
• 2007

Electrochemical reaction of glucose was regulated by the electrochemically active area of nanoporous platinum, which is controlled by ionic strength. The profile of the oxidation current of glucose vs. ionic strength was identical with that of the electrochemically active area. This result confirms that the nanopores are virtually opened for the electrochemical reaction of glucose when the ionic strength climbs over a specific concentration and implies that the electrochemical reactions on nanoporous electrode surfaces can be controlled by concentration of electrolyte.

• Journal of Electrochemical Science and Technology
• /
• v.4 no.3
• /
• pp.93-101
• /
• 2013

The electrodeposition of indium onto a copper electrode from an aqueous sulfate solution containing $In^{3+}$ was studied by means of cyclic voltammetry and chronoamperometry. Reduction and oxidation of indium on copper were investigated by using cyclic voltammograms at different negative limiting potentials and at different scan rates in cumulative cycles. Cyclic voltammograms indicated that reduction and oxidation processes of indium could involve various reactions. Chronoamperometry was carried out to analyze the nucleation mechanism of indium in the early stage of indium electrodeposition. The non-dimensional plot of the current transients at different potentials showed that the shape of the plot depended on the applied potential. The nucleation of indium at potential step of -0.6~-0.8 V was close to progressive nucleation limited by diffusion. However the non-dimensional plot of current transients for the indium nucleation showed different behaviors from theoretical curves at the potential step lower than -0.8 V.

• Journal of Electrochemical Science and Technology
• /
• v.3 no.1
• /
• pp.1-13
• /
• 2012

Many researchers focus on indium contained semiconductors and alloy compounds for their various applications. Electrochemists want to obtain indium contained compounds simply via one-step electrodeposition. First of all, electrochemistry of constituent elements must be understood in order to develop the best condition for the electrodeposition of indium contained compounds. We will review the electrochemistry of indium. Equilibria between indium metal and indium ions and the standard electrode potentials of the equilibria will be reviewed. The electrochemical reactions of indium species are affected by surrounding conditions. Thus dependences of electrochemical behaviors of indium metal and indium ions on various parameters will be reviewed.