• Journal of the Korean Ceramic Society
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• v.40 no.8
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• pp.735-738
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• 2003

The PTFE composites for the microwave printed circuit board were prepared using woven glass fiber. The dielectric constant of the PTFE composites with oven glass fiber tended to decrease with an increase of immersion time, and was saturated at 3 times immersion. It resulted from the fact that fine powders of PTFE filled up at the pore and bend of woven glass fiber sufficiently. As the immersion time increased, the propagation velocity increased due to the reduction of dielectric constant.

• Journal of Chest Surgery
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• v.34 no.4
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• pp.322-328
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• 2001

배경: 우심실 유출로 재건술후에는 폐동맥판막부전이 우심실기능에 나쁜 영향을 미친다. 이를 막기 위해 여러 재료로 판막을 제조하여 사용하는데 가피 형성이 적은 막형 ePTEE(expanded polytetrafluoroethylene, Goretex) 단엽판막의 효과를 알아보고자 연구를 시행하였다. 대상 및 방법; 1996년 3월부터 1997년 2월까지 우심실유출로 재건술을 시행받고 수술 1일까지 우심실 압력을 측정할 수 있었던 47명중 막형 Goretex단엽판막을 사용한 환자(비교군) 19명, 사용하지 않은 환자(대조군) 28명에서 단엽판막의 유용성을 조사하였다. 두 군간에는 나이, 체중 그리고 McGoon ratio 등에는 통계학적 차이가 없었다.(p>0.05) 이전의 수술은 대조군에서 19번, 비교군에서 22번을 시행하였다. 우심실 유출로에 대한 수술은 대조군에서 REV수술 2예, 우심실폐동맥 연결수술 8예, 우심실 유출로 재개건술 2예, 우심실 유출로에 대한 수술은 대조군에서 16예였으며, 비교군에서는 REV 수술 5예, Rastelli 씨 수술 6예, 재우심실 유출로 재건술 5예, 그리고 우심실 재건술 3예였다. 결과: 대동맥 차단 시간이나 총심폐순환시간에는 두군간의 차이는 없었다. 또한 수술직후와 수술후 1일째 측정한 우심실 압력 및 좌심방압력의 차이도 두군간에는 차이가 없었으며 수술후 7일째 시행한 심에코도 결과 ejection fraction., 우심실/ 좌심실 압력비 , 그리고 우심실 유출로의 압력차, 강심제 투여일수, 호흡기 사용 기간 등에서도 두군간의 차이는 없었으나 흉관 삽입기간이 비교군에서 의미있게 짧았다. 추적 조사 기간 중 비교군 1예에서 사망을 하였으나. Goretex 단엽판막에 의한 것은 아니였으며 심초음파검사상 우심실 유출로 압력차이나 재수술은 두군간에 차이는 없었으나 폐동맥 폐쇄부전은 비교군에서 의미 있게 낮은 것을 보이고 있다. 결론; 막형 Goretex 단엽판막의 조기성적은 우수하였으며 폐동맥 폐쇄분전의 정도를 적게 하는 효과를 보이나 앞으로 이들이 성장함에 따라 우심실 유출로에 폐쇄를 일으키는지는 계속적인 추적관찰이 요구된다.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.134-136
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• 2003

In this work, we have seen the effect of hole-transporting layer in organic light-emitting diodes using N,N'-biphenyl-N,N'-bis-(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine(TPD) and N,N'-biphenyl-N,N'-bis-(1-naphenyl)-[l,l'-biphenyl]-4,4'-diamine(NPB). NPB is regarded as a better hole trans porting material than TPD, since it has a higher glass transition temperature($T_g$). And current-voltage, luminance-voltage and external quantum efficiency of device were measured with the thickness variation of buffer layer using copper phathalocyanine(CuPc) am polytetrafluoroethylene (PTEE) at room temperature. We have obtained an improvement of External quantum efficiency when the CuPc 30[nm] and PTFE 1.0[nm] is used.

• Bulletin of the Korean Chemical Society
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• v.12 no.3
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• pp.290-295
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• 1991

A semi-automatic method for the determination of dissolved bismuth at parts per trillion levels is described. The method involves bismuthine generation, in situ collection of bismuthine in a graphite furnace, and atomic absorption detection. In order to facilitate semi-automation of bismuthine generation and separation from aqueous solution, Gore-tex microporous PTEE membrane is used. The absolute detection limit, taken as three times the standard deviation of the instrument noise is 2 pg. The precisions are 3.1% for 100 pg and 1.9% for 1 ng of bismuth, respectively. As many as 90 measurements can be made in an hour.

• Journal of Chest Surgery
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• v.16 no.1
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• pp.91-96
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• 1983

A study was carried out to observe the clinical progress and results after modified Blalock-Taussing shunts on II patients with cyanotic complex heart diseases unsuitable for corrective surgery. The operation was performed by interposing a vascular prosthesis [PTEE] between the left subclavian artery and the left pulmonary artery. Vascular prostheses larger than the diameter of left subclavian artery were selected. The results were as follows: 1. The postoperative courses in 10 patients were uneventful without any complications. One patient died of low cardiac output syndrome immediate postoperatively. 2. The average value of RBC count before operations was 751.2291.68 [xl00]/cubic mm. It was decreased to 588.11 90.45 [xl 0,000]/cubic mm. After the operation. 3. The average value of Hemoglobin before operations was 20.07 3.01 mg/dl. The value was decreased to 15.361.68mg/dl after the operation. 4. The value of Hematocrit before operations was 62.878.89%. The value was decreased to 49.6 5.84% 5. Patency after the shunt operations using PTFE was good for maximal 16 months follow-up period. 6. The physiological impairment like anoxic spells, degree of cyanosis and other clinical symptoms were markedly improved after the shunt operations. Although a longer follow-up seems to be necessary to assess the validity of these shunts, the early results were encouraging.

• Journal of Energy Engineering
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• v.1 no.1
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• pp.58-65
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• 1992

Pt loaded porous carbon Pt/C electrode was prepared by hot pressing process to enhance the electrode performance in PAFC (phosphoric acid fuel cell). By changing the hot pressing conditions and PTFE contents, Pt/C electrodes were prepared and the electrochemical characteristics of oxygen reduction and unit-cell performance were evaluated. The optimum condition of hot press to make electrode is 360$^{\circ}C$ and 10 kg/$\textrm{cm}^2$. Maximum performance was obtained at 30 wt% PTFE content in the catalyst layer with 80% utilization of platinum clusters. Unit-cell performance of hot pressed Pt/C electrode was 200 mA/$\textrm{cm}^2$ at 700 ㎷ and stable performance was maintained more than 200 hr.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.645-648
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• 2005

The grounds of multipurpose practical use degree are built much holding world cup 2002 but material that is used in this building most external membrane ceiling is accomplishing PTEE A master and servant. Therefore, this research analyzed assessment about sound absorption special quality that measure ventilation quantitys of 10 act material and analyze correlation with Air Permeability and the sound absorption rate, and follow in change of layer of air of inside facts material. Result is as following. When Air Permeability good dimension is 5$\sim$15 cc/cm$^2$/sec and acoustic absorptivity is the best as Air Permeability result that measure acoustic absorptivity of inside facts material particularly firstly, could know 8$\sim$9 cc/cm$^2$/sec love. When establish sound absorption inside facts in external membrane as result that measure acoustic absorptivity of inside (acts material secondly, could know that acoustic absorptivity is good though become about minimum back layer of air 900mm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.9A
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• pp.867-875
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• 2005

In this paper, we fabricated along distance wireless communication transmitter and receiver over the 100 which used NRD technology. To make the transmitter and receiver of 400Hz band using the non radiative dielectric wave guide, transmitter was composed of gm oscillator, m modulator and antenna, receiver was composed of local gum oscillator, balanced mixer, 3dB direction coupler and antenna. Also we executed a wireless communication image transmission examination to the transmitter and receiver. We receive the image information in real-time data transmission from receiver after we send the image signal in the wireless distance of the 10km. Therefore, the 400Hz band U transmitter and receiver to be developed will be used widely for the transmission system CATV or broadband transmission system. This will be utilized also to the link device of a long distance high speed wireless communication network.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.57-74
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• 2001

The purpose of this study was to evaluate the adjunctive combined effect of demineralized freeze-dried bone allograft(DFDB) in guided bone regeneration on supra-alveo-lar peri-implant defect. Supra-alveolar perio-implant defects, 3mm in height, each including 4 IMZ titanium plasma-sprayed implants were surgically created in two mongrel dogs. Subsequently, the defects were treated with 1 of the following 3 modalities: Control) no membrane or graft application, Group1) DFDB application, Group2) guided bone regeneration using an expanded polytetra-fluoroethylene membrane, Group3) guided bone regeneration using membrane and DFDB. After a healing period of 12-week, the animals were sacrificed, tissue blocks were harvested and prepared for histological analysis. Histologic examination were as follows; 1. New bon formation was minimal in control and Group 1, but considerable new bone formation was observed in Group 2 and Group 3. 2. There was no osteointegration at the implant-bone interface in the high-polished area of group2 and Group 3. 3. In fluorescent microscopic examination, remodeling of new bone was most active during week 4 and week 8. There was no significant difference in remodeling rate between group 2 and group 3. 4. DFDB particles were observed, invested in a connective tissue matrix. Osteoblast activity in the area was minimal. The results suggest that guided bone regeneration shows promising results in supra-alveolar peri-implant defects during the 12 week healing period although it has a limited potential in promoting alveolar bone regeneration in the high-polished area. There seems to be no significant adjunctive effect when DFDB is combined with GBR.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.1
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• pp.53-59
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• 2001

Surfaces of PTFE and PVDF were modified by ion-assisted reaction (IAR) in which 1 keV $Ar^{+}$ ions were irradiated on the surface of the polymer with varying ion dose in an oxygen gas environment, and Cu, Pt, Al and Ag thin films were deposited on the modified polymers. Wettability of the modified polymers was largely improved by the formation of hydrophilic groups due to chemical reaction between polymer surface and the oxygen gas during IAR. The change in wettability in the modified polymers was also related to the change in surface morphology and roughness. Adhesion between metal films and polymers modified by IAR was significantly improved, so that no detachment was possible in the $Scotch^{TM}$ tape test. The increase of adhesion strength between the metal film and the modified PVDF was mainly attributed to the formation of hydrophilic groups, which interacted with the metal film. In the case of the modified PTFE, the enhanced adhesion to metal film could be explained by the change in surface morphology together with the formation of hydrophilic groups. The electrical properties of the metal films on the modified polymers were also investigated.