• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2006년도 춘계학술대회
• /
• pp.154-157
• /
• 2006

The counter electrode widely used in DSCs (Dye-sensitized Solar Cells) is constructed of conducting glass substrates coated with Pt films, where the platium acts as a catalyst. Pt counter electrodes in DSCs are one important component. It is expected that characteristics of Pt electrodes strongly depend on fabrication process and its surface condition. In this study, Pt counter electrode surface of DSC is deposited by reactive RF magnetron sputtering under the conditions of Ar 5mtorr, RF power of 120w and substrate temperature of $100^{\circ}C$. Surface morphology of Pt electrodes was investigated by FE-SEM and AFM. And this paper shows our recent results and technology to fabricate the new designed cell with Pt electrodes deposited by sputtering method. We have achieved fill factor 65% and photoelectric conversion efficiency around 2.6% as the best results of new designed DSCs structure.

• 공학기술논문지
• /
• 제11권4호
• /
• pp.267-271
• /
• 2018

A high-frequency therapy device with improved output by modifying a high-frequency stimulator was fabricated. The details of the design include generating part design, high-frequency transformer design, large output FET installation, DC voltage input part design and gate input driver design. Based on the real test using the pork meat, the temperature distributions according to the current electric transfer method, penetration depth, electrode diameter size were measured. In the CET method, the penetration depth was 0.5 cm and in the RET method, the penetration depth was 20 cm or more. In addition, it was confirmed that the temperature rise according to the penetration depth in the RET system was substantially constant, and the temperature rise was remarkable as the electrode diameter was small. As a result, it has been confirmed that the high frequency therapy device is highly affected by various conditions of the electrode.

• 전기학회논문지
• /
• 제67권12호
• /
• pp.1626-1632
• /
• 2018

In this paper, we describe the fabrication and characterization of a hydrogen peroxide ($H_2O_2$) sensor based on palladium and copper (PdCu) electroplated laser induced graphene (LIG) electrodes. $CO_2$ laser was used to form LIG electrodes on a PI film. This fabrication method allows simple control of the LIG electrode size and shape. The PdCu was electrochemically deposited on the LIG electrodes to improve the electrocatalytic reaction with $H_2O_2$. The electrochemical performance of this sensor was evaluated in terms of selectivity, sensitivity, and linearity. The physical characterization of this sensor was conducted using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), which confirmed that PdCu was formed on the laser induced graphene electrode. In order to increase the sensor sensitivity, the Pd:Cu ratio of the electroplated PdCu was varied to five different values and the condition of highest amperometric current at an identical of $H_2O_2$ concentration was chosen among them. The resulting amperometric current was highest when the ratio of Pd:Cu was 7:3 and this Pd;Cu ratio was employed in the sensor fabrication. The fabricated PdCu/LIG electrode based $H_2O_2$ sensor exhibited a sensitivity of $139.4{\mu}A/mM{\cdot}cm^2$, a broad linear range between 0 mM and 16 mM of $H_2O_2$ concentrations at applied potential of -0.15 V, and high reproducibility (RSD = 2.6%). The selectivity of the fabricated sensors was also evaluated by applying ascorbic acid, glucose, and lactose separately onto the sensor in order to see if the sensor ourput is affected by one of them and the sensor output was not affected. In conclusion, the proposed PdCu/LIG electrode based $H_2O_2$ sensor seems to be suitable $H_2O_2$ sensor in various applications.

• 대한전기학회논문지
• /
• 제40권1호
• /
• pp.73-81
• /
• 1991

In order to simulate the ceramic filter in the state of the one-strip electrode, the theory has been analyzed and a computer program has been developed using the energy trapping effect. The ceramic filters were fabricated using the PZT-4 specimen. The necessary condition that the ceramic filter has the energy trapping effect is that the electroded portion frequency should be smaller than the unelectroded portion frequency when the wave number is zero. Each of the average differences of the resonant point and bandwidth between by the theoretical calculations and by experiment results was 5.6[%] and 3.72[%]. It is considered that the one-strip ceramic filter having a desired characteristics and the lowest difference can be fabricated easily by means of the simulation developed in this paper and the fabrication methods.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.501-504
• /
• 2004

This paper describes the fabrication method for atomic force microscopy(AFM) tip with multi-walled carbon nanotube(MWNT). For making a carbon nanotube (CNT) modified tips, AC electric field which cause the dielectrophoresis was used for alignment and deposition of CNTs in this research. By dropping the MWNT solution and applying an electric field between an AFM tip and an electrode, MWNTs which were dispersed into a diluted solution were directly assembled onto the apex of the AFM tips due to the attraction by the dielectrophoretic force. In this case, we investigate the effect of the angle between a tip axis and an electrode. Experimental setup were presented, and then CNT attached AFM tips are successfully shown in this paper.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제52권10호
• /
• pp.436-440
• /
• 2003

The (S $r_{0.85}$C $a_{0.15}$)Ti $O_3$(SCT) thin films were deposited on Pt-coated electrode(Pt/TiN/ $SiO_2$/Si) using RF sputtering method according to the deposition condition. The optimum conditions of RF power and Ar/ $O_2$ ratio were 140[W] and 80/20, respectively. Deposition rate of SCT thin films was about 18.75[$\AA$/min] at the optimum condition. The composition of SCT thin films deposited on Si substrate is close to stoichiometry (1.102 in A/B ratio). The capacitance characteristics had a stable value within $\pm$4[%]. The drastic decrease of dielectric constant and increase of dielectric loss in SCT thin films were observed above 200[kHz]. SCT thin films used in this study showed the phenomena of dielectric relaxation with the increase of frequency.ncy.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 D
• /
• pp.1500-1502
• /
• 1998

Electro Discharge Machining (EDM) is a so-call nonconventional machining technique. This paper presents the experimental results of an EDM technique for the fabircation of microholes on #7440 pyrex glass substrates. With various applied voltages and various concentration of NaOH or KOH solution, the glass substrates have been microdrilled using the copper electrodes of which diameters are 250 ${\mu}m$ to 450 ${\mu}m$. The machined throughholes have been observed the top diameter, the bottom diameter and machining time have been measured. EDM in NaOH solution causes the fabrication to have better the surface condition, higher selective of electrode, lower concentration of solution with respect to EDM in KOH solution machined fabrication.

• 한국표면공학회지
• /
• 제32권3호
• /
• pp.456-460
• /
• 1999

Transparent conducting tin (IV) oxide thin films have been studies and developed for the electrode materials of solar cell substrate. Fabrication of tin oxide thin films by sol-gel method is process development of lower cost photovoltaic solar cell system. The research is focused on the establishment of process condition and development of precursor. The precursor solution was made of tin isopropoxide dissolved in isopropyl alcohol. The hydrolysis rate was controlled by addition of triethanolamine. Dip and spin coating technique were applied to coat tin oxide on borosilicate glass. The resistivity of the thin film was lower than 0.1Ω-cm and the transmittance is higher than 90% in a visible range.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 하계학술대회 논문집
• /
• pp.391-394
• /
• 2002

Transparent conductive oxides (TCO) are necessary as front electrode for most thin film solar cell. In our paper, transparent conducting aluminum-doped Zinc oxide films (ZnO:Al) were prepared by rf magnetron sputtering on glass (Corning 1737) substrate as a variation of the deposition condition. After deposition, the smooth ZnO:Al films were etched in diluted HCl (0.5%) to examine the electrical and surface morphology Properties as a variation of the time. The most important deposition condition of surface-textured ZnO films by chemical etching is the processing pressure and the substrate temperature. In low pressures (0.9 mTorr) and high substrate temperatures ($\leq$30$0^{\circ}C$), the surface morphology of films exhibits a more dense and compact film structure with effective light-trapping to apply the silicon thin film solar cells.

• Tribology and Lubricants
• /
• 제37권6호
• /
• pp.203-207
• /
• 2021

This study presents the development of dielectric constant sensors to measure lubricant properties. The lubricant oil sensor is used to measure oil properties and machine conditions. Various condition monitoring methods are applied to diagnose machine conditions. Machine condition monitoring using oil sensors has advantage over other machine condition monitoring methods. The fault conditions can be noticed at the early stages by the detection of wear particles using oil sensors. Therefore, it provides an early warning in the failure procedure. A variety of oil sensors are applied to check the machine condition. Among all oil sensors, only one sensor can measure the tendency of several properties such as acidity and water content. A dielectric constant sensor is also used to measure various oil properties; therefore, it is very useful. The dielectric constant is the ratio of the capacitance of a capacitor using that material as a dielectric to that of a similar capacitor using vacuum as its dielectric. The dielectric constant has an effect on water content, contaminants, base oil, additive, and so forth. In this study, the dielectric constant sensor is fabricated using MEMS process. In the fabrication process, the shape, gap of the electrode array, and thickness of the insulation material are considered to improve the sensitivity of the sensor.