• Electrical & Electronic Materials
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• v.4 no.1
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• pp.45-52
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• 1991

본 논문은 기중 코로나 방전에 의하여 생성된 캐리어를 Teflon-FEP 표면에 균일하게 공급하였을 때 Teflon-FEP를 통하여 흐르는 코로나 대전전류 특성에 대하여 연구하였다. 불소를 함유한 Teflon-FEP는 코로나 대전전류에 극성효과가 현저히 나타난다. 즉 정극성 캐리어는 벌크내를 쉽게 이동하나 부극성 캐리어는 안정하게 trap되어 벌크내를 이동하기 어렵기 때문에 부극성 코로나 대전전류 보다 정극성 코로나 대전전류가 크게 흐름을 알았다. 이와같이 극성효과가 나타나는 것은 Teflon-FEP가 전자 친화력이 있는 불소를 함유하고 있기 때문임을 제시하였다. 이러한 사실은 Polysulfone(PSF), High density Polyethylene(HDPE) 및 Polythylene Terephtarate(PET)의 코로나 대전전류 특성으로부터 확인할 수 있었다.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.1
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• pp.138-143
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• 2017

A performance analysis for a pulsed plasma thruster(PPT) has been conducted to predict the thrust and current change. Two models were implemented - a one-dimensional lumped circuit analysis model and the Teflon ablation model provided by Michael Keidar. The circuit model incorporating resistance and inductance models was adapted to predict the magnitude of the discharge current. Numerical simulations like current discharge rates with different voltages were reasonably well compared with experimental data. The effects of Teflon ablation on thruster characteristics were investigated.

• Journal of the Optical Society of Korea
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• v.19 no.6
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• pp.560-565
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• 2015

We report efficient direct coupling of THz dipole antenna pulses onto air spaced two-wire transmission lines and Teflon covered two-wire lines. The air spaced two-wire lines show TEM mode propagation with very small group velocity dispersion (GVD) and relatively low attenuation. The Teflon covered two-wire lines showed comparatively much higher attenuation and GVD. However, the Teflon covered two-wire lines show a very good guiding property when the lines are curved. Although the lines are circled only 5.0 cm in diameter, there is no additional attenuation compared to straight the lines.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.E1
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• pp.35-41
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• 2004

Aerosol wall loss is an important factor affecting smog chamber experiments, especially with chambers made of Teflon film. In this work, the aerosol wall loss was investigated in 2.5 and $5.8-m^3$ cubic-shaped Teflon film chambers filled with ambient air. The natural change in the particle size distribution was measured using a scanning mobility particle sizer in a dark environment. The rate of aerosol wall loss was obtained from the deposition theory suggested by Crump and Seinfeld (1981). The measured rates of aero-sol wall loss were In a good agreement with the theoretical and experimental values given by McMurry and Rader (1985), implying that the electrostatic effect enhances particle deposition on the chamber wall. The significance of aerosol wall loss correction was demonstrated with the photochemical reaction experiments using the ambient air.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.8
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• pp.693-699
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• 2003

To improve thermal stability of Teflon FEP which is the most widely used materials for electret application, Teflon AF film of 1 $\mu\textrm{m}$ thick was spin coated on FEP film and the charge storage properties were investigated. The surface potential depend on aging temperature. Thermal Stimulated Current(TSC), Atomic Force Microscopy(AFM), and Fourier Transform-Infrared Spectroscope(FT-lR) measurements were carried out. It is shown that the AF/FEP dual film have more higher electrical property and thermal stability than that FEP film have caused by charge stored at interface of AF and FEP.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1413-1414
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• 2003

일렉트렛을 이용한 전자제품의 시공정에 주로 이용되고 있는 Teflon FEP 일렉트렛의 전하 저장 특성을 개선하기 위하여 FEP 필름 위에 Teflon AF 1${\mu}m$를 적충한 후 그 전기적 특성을 분석하였다. AF/FEP 이중 필름을 음극 코로나 방전에 의해 하전시켰으며, 반복 하전 및 열처리에 따른 표면전위 변화를 관찰하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.164-165
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• 2015

보일러 및 압력 용기용 강판으로 사용되는 SB410은 고 항복 강도 및 좋은 용접성의 특성을 가진 재질로서 주로 고압력, 내열성 및 내식성이 필요한 석유플랜트, 액화물 저장 탱크, 화력 발전 보일러 등의 제조에 주로 사용되어지는 탄소 강재이다. 그러나, 최근에는 조선소, 해양 플랜트, 석유화학 플랜트 등 사용환경에 따른 관련 분야에서의 내식성 요구치가 높아지고 있다. 이와 관련하여 현재 보편적으로 사용되어지는 Marin paint coating을 적용한 SB410 강재의 경우에도 사용환경의 가혹화가 증가됨에 따라 요구되는 내식성에 비하여 불량 현상이 증가하는 추세이며 해당 분야에서 본 재질의 표면처리 개선에 대한 연구 개발이 진행되고 있다. 본 연구에서는 Teflon(PTFE) synthetic coating solution을 이용한 SB410 소재 상의 표면처리 공정 최적화를 수행하였으며, 상기 표면처리에 대한 내식성을 검토하기 위하여 Marin paint coating sample, Teflon(PTFE) synthetic coating sample들에 대한 갈바닉 부식 분석 비교를 통하여 내식성에 대한 비교 검증을 수행하였다.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.738-748
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• 2017

Objective : We present our experience of microvascular decompression (MVD) for glossopharyngeal neuralgia (GPN) and evaluate the postoperative outcomes in accordance with four different operative techniques during MVD. Methods : In total, 30 patients with intractable primary typical GPN who underwent MVD without rhizotomy and were followed for more than 2 years were included in the analysis. Each MVD was performed using one of four different surgical techniques : interposition of Teflon pieces, transposition of offending vessels using Teflon pieces, transposition of offending vessels using a fibrin-glue-coated Teflon sling, and removal of offending veins. Results : The posterior inferior cerebellar artery was responsible for neurovascular compression in 27 of 30 (90%) patients, either by itself or in combination with other vessels. The location of compression on the glossopharyngeal nerve varied; the root entry zone (REZ) only (63.3%) was most common, followed by both the REZ and distal portion (26.7%) and the distal portion alone (10.0%). In terms of detailed surgical techniques during MVD, the offending vessels were transposed in 24 (80%) patients, either using additional insulation, offered by Teflon pieces (15 patients), or using a fibrin glue-coated Teflon sling (9 patients). Simple insertion of Teflon pieces and removal of a small vein were also performed in five and one patient, respectively. During the 2 years following MVD, 29 of 30 (96.7%) patients were asymptomatic or experienced only occasional pain that did not require medication. Temporary hemodynamic instability occurred in two patients during MVD, and seven patients experienced transient postoperative complications. Neither persistent morbidity nor mortality was reported. Conclusion : This study demonstrates that MVD without rhizotomy is a safe and effective treatment option for GPN.

• Journal of the Korea Safety Management & Science
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• v.19 no.4
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• pp.35-42
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• 2017

A number of plating companies have been exposed to the risk of fire due to unexpected temperature increasing of water or other reasons in a plating bath. Since the companies are not able to forecast the unexpected temperature increasing of plating bath and most of raw materials in the bath have low ignition temperature, it is easy to be exposed to the risk of fire. Thus, in previous study, we tried to monitor and notice the dangerous change of temperature of water immediately to prevent the risk of fire from plating process. However, unfortunately previous studies were not able to shut out the fundamental cause of fire since bath temperature sensor can detect air temperature when the level sensor was malfunctioned. In this paper we developed the Teflon heater which contains a built in temperature sensor and improved plating equipment system. Teflon heater is improved using Pt $100{\Omega}$ sensor which can detect until $600^{\circ}C$. When the bath temperature sensor detects over $60^{\circ}C$ or the Teflon heater sensor detects over $240^{\circ}C$ they temporarily shut down the heater to control temperature. Also relay completely shuts down main power when detects instant temperature is detected over 5% of $240^{\circ}C$ by the heater sensor to prevent teflon melting down and fire spreads. Developed plating equipment system can monitor a real time temperature in the teflon tube and bath water. Therefore we think the proposed plating equipment can eliminate the possibility of fire in plating processes fundamentally.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.3
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• pp.25-32
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• 2021

In this paper, the Magneto-Electric(ME) dipole array antenna with dual-polarization in the X-Band is proposed and it is implemented and measured. The proposed array antenna is composed of 32 single ME dipole antenna and a Teflon PCB. 1 × 1 ME dipole antenna is implemented dual-polarization by radiating vertical polarization and horizontal polarization from two pairs of radiators. 2-port feeding structures are realized by lamination process using LTCC. And, each port independently feeds the radiator through a Γ-shaped feeding strip with isolation between ports. The Teflon PCB used in the antenna array has a 4-layer structure, and 2-port is fed through the top and bottom layers. The λ_g/4 transformer is applied to the transmission line of the Teflon PCB for impedance matching of the arrayed antenna and the Teflon PCB, and the optimal parameters are obtained through simulation. The measured maximum antenna gains of port 1 was 18.2 dBi, Cross-pol was 1.0 dBi. And the measured maximum antenna gains of port 1 was 18.1 dBi, Cross-pol was 3.2 dBi.