• Journal of Sensor Science and Technology
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• v.19 no.2
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• pp.149-154
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• 2010

Top of the alumina body which is made according to plan has been printed using a screen printer equipment in order to print an electrode pattern. The electrode is connected with the quartz crystal oscillator of the piezoelectricity method which has a piezoelectric characteristic. The pressure contact department has been experimented using three type of the teflon. The teflon is good for pressure delivery vector but it is bad restitution. So we devised the structure which inserts the metal in the teflon. Bottom of the module is connected with the signal processing department which is planned in advance and then has investigated to characteristic. Therefore we have got the best output-voltage and frequency characteristic follows in the pressure.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.1
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• pp.35-40
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• 2000

Teflon-like fluorocarbon thin film was deposited on various substrates by vapor deposition using PFDA (perfluorodecanoic acid). The fluorocarbon films were characterized by static/dynamic contact angle analysis, VASE (Variable-angle Spectroscopic Ellipsometry) and AFM/LFM (Atomic/Lateral Force Microscopy). Based on Lewis Acid/Base theory, the surface energy ($S_{E}$) of the films was calculated by the static contact angle measurement. The work of adhesion (WA) between de-ionized water and substrates was calculated by using the static contact data. The fluorocarbon films showed very similar values of the surface energy and work of adhesion to Teflon. All films showed larger hysteresis than that of Teflon. The roughness and relative friction force of films were measured by AFM and LFM. Even though the small reduction of surface roughness was found on film on $SiO_2$surface, the large reduction of relative friction farce was observed on all films. Especially the relative friction force on TEOS was decreased a quarter after film deposition. LFM images showed the formation of "strand-like"spheres on films that might be the reason far the large contact angle hysteresis.

• Journal of ILASS-Korea
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• v.10 no.2
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• pp.18-31
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• 2005

This study was performed to explore the liquid breakup and atomization characteristics for the classification of drop formation mode and background of uniform droplets generation in electrohydrodynmaic atomization according to the change of experimental parameters such as nozzle material (stainless steel. teflon). fluid flow rate, applied electrical field and intensity, and frequency. In results, from the classification map of drop formation modes according to the variation of applied AC voltage and frequency at a stainless nozzle, the droplet size was smaller than the outer diameter of the nozzle tip relatively in the spindle mode. The transition points became clearly to be moved toward the high applied voltage by rising the applied AC frequency beyond 450Hz. Also the droplet radius can be observed quite small in the frequency bandwidth of $350{\sim}450Hz$. The droplet radiuses decrease as the applied voltage increases for a fixed applied AC frequency within the range from 50Hz to 400Hz Over 400Hz, the relation between the power intensity and the droplet size was not consistent with a continuous mechanism of liquid breakup. Thus, it is showed that the droplet size distribution using the teflon nozzle was analogous to the results of stainless steel, but the droplet size was bigger than that of stainless steel relatively in case of a teflon nozzle.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.69-74
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• 2018

With the increasing development of industrial society and the availability of high quality electrical energy, the simplification of operation and maintenance procedures is required, in order to ensure the reliability and safety of electrical systems. In this paper, the dielectric breakdown characteristics of $N_2-O_2$ mixed gas solid insulation, which is used as an alternative to SF6 in various electric power facilities, are verified. When the gas mixture has a composition ratio similar to that of the atmosphere, the dielectric breakdown characteristics are relatively stabilized. It was confirmed that the breakdown voltage of the gas in the electrode near an equal electric field increased with increasing pressure according to Paschen's rule. The breakdown voltage of the surface increased linearly with increasing pressure, and the difference was caused by the mixing ratio of $O_2$ gas. This change in the surface insulation breakdown voltage was caused by the influence of the electrically negative $O_2$ gas and the intermolecular collision distance. In this study, the influence of the intermolecular impact distance was larger (than that in the absence of the electrically negative $O_2$ gas). The breakdown voltage relation applicable to Teflon according to the surface insulation characteristics was calculated. The characteristics of the surface insulation properties of Teflon, which is used as a solid insulation material, were derived as a function of pressure. It is thought that these results can be used as the basic data for the insulation design of electric power facilities.

• Journal of the Korean Geotechnical Society
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• v.34 no.1
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• pp.5-16
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• 2018

In this study, seismic performance of geotechnical seismic isolation system capable of primary seismic isolation in the ground was evaluated. 1-G shaking table test was used to assess the performance of Teflon or steel slag as geotechnical seismic isolation systems installed beneath superstructure foundation. Response acceleration and response spectra were analyzed considering different input motions. The results were compared with those of fixed foundation structure without seismic isolation system. The steel slag-type seismic isolation system showed significant reduction in acceleration. The teflon-type seismic isolation system did not show significant effects on acceleration reduction in low-to-moderate seismicity condition, but it did show better effects in case of strong seismic condition. As input motion was transferred to the upper mass, the response spectrum of the fixed foundation structure was amplified in the short period range. In contrast, the response spectrum of the structure with seismic isolation using teflon or steel slag amplified in the long period range. It is found that the change of periodicity and the friction characteristics between isolation materials and foundations affected acceleration reduction.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.233.1-233.1
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.540-568
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• 2006

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.6
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• pp.945-952
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• 1987

In this paper, Crack molding method called "Teflon crack Molding Method" is developed. With help of this method, we can mold a crack which is very similar to the natural crack, which has the tip radius of about 20.mu. the vertical and horizontal quality of crack excellent. In addition to these, by using this method in photoelastic experiment we can obtain the clear crack tip location and Isochromatic fringe pattern boundary, therefore the precise in the experimental data can be improved. improved.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.1
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• pp.74-83
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• 2007

Artifacts due to inter-particle and gas-particle interactions during PM2.5 sampling were quantified by comparing the measurement results between the annular denuder-filterpack system and the filterpack system without denuder. Measurements were carried in Seoul for 10 days in each season; Nov. 2004, Jan. 2005, Mar. 2005, and Jul. 2005, respectively. In each day, two 12-h samples were obtained. The concentrations of nitrate and chloride showed seasonal variations mainly due to the availability of ammonium to neutralize nitrate or chloride. Nitrates and chloride losses were prominent in summer. Since most of ammonia was used to neutralize sulfuric acid and formed ammonium sulfate in summer, nitrate and chloride could not exist in particles and ammonium loss was smaller than other seasons.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2173-2174
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• 2011

At the moment, the section insulators for different phases used for over head contact wire system has been all imported since its first application. However, because the section insulators need frequent maintenance and replacement due to the wear by the friction with pantograph and the contamination, which causes its life shorter than as expected, it is required to develop the insulation material with better wear-resistance characteristics and contamination-resistance characteristics. In this thesis, the author developed the section insulator which adopts Teflon tube insulation material which is composed of the Teflon material with the excellent electrical characteristics and wear-resistance characteristics for a longer expected life than that made of conventional FRP.