아르곤 플라즈마를 이용하여 유리기판에 증착된 PTFE 박막의 초친수 특성 연구

이병로,배강,김화민,Rhee, Byung Roh,Bae, Kang,Kim, Hwa-Min 한국전기전자재료학회 2014 전기전자재료학회논문지 Vol.27 No.8

An excellent hydrophobic surface has a high contact angle over 147 degree and the contact angle hysteresis below $5^0$ was produced by using roughness combined with hydrophobic PTFE coatings, which were also confirmed to exhibit an extreme adhesion to glass substrate. To form the rough surface, the glass was etched by Ar-plasma. A very thin PTFE film was coated on the plasma etched glass surface. Roughness factors before or after PTFE coating on the plasma etched glass surface, based on Wensel's model were calculated, which agrees well with the dependence of the contact angle on the roughness factor is predicted by Wensel's model. The PTFE films deposited on glass by using a conventional rf-magnetron sputtering. The glass substrates were etched Ar-plasma prior to the deposition of PTFE. Their hydrophobicities are investigated for application as a anti-fouling coating layer on the screen of displays. It is found that the hydrophobicity of PTFE films mainly depends on the sputtering conditions, such as rf-power, Ar gas content introduced during deposition. These conditions are closely related to the deposition rate or thickness of PTFE film. Thus, it is also found that the deposition rate or the film thickness affects sensitively the geometrical morphology formed on surface of the rf-sputtered PTFE films. In particular, 1,950-nm-thick PTFE films deposited for 30 minute by rf-power 50 watt under Ar gas content of 20 sccm shows a very excellent optical transmittance and a good anti-fouling property and a good durability.

협대역 이동통신시스템에서 TTIB를 이용한 페이딩 보상 시스템의 설계 및 구현

이병로,임영회,임동민,Lee, Byeong-Ro,Lim, Young-Hoe,Lim, Dong-MIn 대한전자공학회 1998 電子工學會論文誌, S Vol.s35 No.10

본 논문에서는 TTIB SSB 방식을 이용한 협대역 이동통신시스템에서 페이딩 보상 시스템의 설계 및 구현에 관한 연구를 수행하였다. 다중경로 페이딩 갖는 이동통신채널은 무선통신시스템의 성능을 필연적으로 제한하게 한다. 이러한 다중경로 페이딩은 TTIB SSB 방식에서 파일럿 톤을 이용하여 보상할 수 있다. DSP(digital signal processor)를 이용하여 TTIB SSB 송 ${\cdot}$ 수신기를 구현하였으며 또한 페이딩 보상은 DSP 알고리즘 형태로 수신기에 구현하였다. TTIB SSB 송 ${\cdot}$ 수신기에서 페이딩 보상 성능을 평가하기 위하여 먼저 시뮬레이션을 이용하였다. 시뮬레이션의 결과로 TTIB SSB 송 ${\cdot}$ 수신기에서 페이딩을 보상할 수 있음을 알 수 있었다. 두 번째로 DSP 보드를 이용하여 TTIB SSB 송 ${\cdot}$ 수신기 구현에 대한 실험을 하였고 다음으로 중심 주파수가 145MHz인 RF 회로를 포함하여 실험하였다. 이 실험을 통하여 TTIB SSB 송 ${\cdot}$ 수신기에서 페이딩 보상 성능은 시뮬레이션을 통하여 얻은 결과와 같은 결과를 얻을 수 있었다. In this paper, we studied the design and implementation of fading compensation systems at aspects of narrowband mobile communication using TTIB SSB. The mobile radio channel with multipath fading places fundamental limitations on the performance of wireless communication systems. The multipath fading is compensated using pilot tone in TTIB SSB. The TTIB transceiver was implemented using the prevailing digital signal processing (DSP) techniques and compensation for the multipath fading was incorporated in the receiver in the form of DSP algorithm. In order to evaluate fading compensation performance in TTIB transceiver, we first used computer simulation. In the simulation results, we found that the TTIB transceiver could compensate for the multipath fading as expected. Second, we carried out some experiments on TTIB transceiver implementation with DSP boards and later with hardwares including RF circuits with center frequency of 145MHz. Through these experiments, we found that fading compensation performance in TTIB transceiver was almost as good as that obtained from simulation.

마그네트론 스퍼터링 증착법을 사용하여 순수한 질소 플라즈마에 의해 성막된 고경도 TiN_X 박막의 역학적 특성

이창현,이병로,배강,박창환,김화민,Lee, Chang-Hyun,Rhee, Byung-Roh,Bae, Kang,Park, Chang-Hwan,Kim, Hwa-Min 한국전기전자재료학회 2017 전기전자재료학회논문지 Vol.30 No.8

TiN (titanium nitride) films were prepared using the RF magnetron sputtering technique. The films were deposited by pure $N_2$ plasma sputtering. Their mechanical properties, such as nano-indentation hardness, friction coefficient, and surface wettability, have been investigated. X-ray diffraction (XRD) studies revealed that the orientation of $TiN_X$ films changed towards the (111) orientation with decreasing working pressure due to a strong compressive stress during deposition. The strongest TiN (111) orientation was found when the film was deposited at a working pressure of 1 Pa. This film showed the largest hardness (16 GPa) and smallest friction coefficient (0.17) among the studied samples. Moreover, this film was found to be accompanied by a water-repellent surface with water contact angle more than $100^{\circ}$.

전자-선 증착 기술에 의해 성막된 다양한 무기 박막들의 투습 방지 특성

류성원,이병로,김화민,Ryu, Sung-Won,Rhee, Byung-Roh,Kim, Hwa-Min 한국진공학회 2008 Applied Science and Convergence Technology Vol.17 No.1

다양한 이원자 무기 박막과 이들의 무기 혼합 박막들이 Ca cell 의 봉지 층으로서 전자-선 증착법에 의해 증착되었다. 이러한 Ca cell들은 대기 중에 노출되었을 때 봉지 층을 통과한 수분들이 Ca cell에 흡수되면서 시간이 지남에 따라 Ca cell들은 점진적으로 투명해진다. 이는 가시광 영역에서 Ca cell의 광투과 스펙트럼의 변화를 대기 중 노출시간의 함수로 나타낼 수 있다. Ca cell에서의 수분 흡수가 포화되는 시간 즉, 광투과 스펙트럼이 더 이상 변하지 않는 포화시간을 비교함으로써 봉지층으로 도입된 다양한 무기 박막들의 투습 방지 특성을 조사하였다. $SiO_2$에 $SnO_2$ 또는 ZnO가 첨가된 무기 복합 박막 STO($SiO_2-SnO_2$)와 SZO($SiO_2$-ZnO) 박막은 이원자 무기 박막들과 비교하여 매우 탁월한 투습 방지 효과를 보여주며, 또한 무기 박막의 수분 투과 특성에 영향을 미치는 주요 인자는 박막의 극성(polarizability)과 치밀도(packing density)임이 확인 되었다. Various diatomic inorganic films and their composite films are packed as passivation films covering Ca cells on glass substrates by using an electron-beam evaporation technique. When these Ca cells are exposed to an ambient atmosphere, the water vapor penetrating through the passivation layers is absorbed in the Ca cells, resulting in a gradual progress of transparency in the Ca cells, which can be represented by changes of the optical transmittance in the visible range. Compared with the saturation times for the Ca cells to become completely transparent in the atmosphere, the protection effects of water vapor are estimated for various passivation films. The composite films consisting silicon oxide($SiO_2$) and tin oxide($SnO_2$) or zinc oxide(ZnO) are found to show a superior protection effect of water vapor as compared with diatomic inorganic films. Also, the main factors affecting the permeation of water vapor through the oxide films are found to be the polarizability and the packing density.

기초과학연구논집 - 1991 년 연구실적편 - / 물리학 : CSVT 법에 의해 증착시킨 CdS 박막의 전기적 특성

김화민(Hwa Min Kim),최제헌(Jae Hun Choi),이병로(Byung Roh Rhee),김태만(Tae Man Kim) 대구가톨릭대학교 자연과학연구소 1991 기초과학연구논문집 -연구실적편- Vol.1991 No.-

유리체강내 특정 트리암시놀론주입 후 발생한 투명기름방울모양 잔존물

강성민,박영숙,이병로,Sung Min Kang,Young Sook Park,Byung Ro Lee 대한안과학회 2007 대한안과학회지 Vol.48 No.5

Purpose: To invest characteristics of the clear oil-drop residue observed in the vitreous cavity after intravitreal triamcinolone acetonide injection (IVTA). Methods: Fifty three eyes which received a IVTA for the treatment of macular edema due to a variety of causes were enrolled in the study. Slit-lamp examination, and dilated fundoscopic examination had been performed in all patients from injection to at least two months. We compared Group 1 (nonpurified triamcinolone injection) to Group 2 (purified triamcinolone injection). Results: The clear oil-drop residues were mainly observed in the superior portion of the vitreous cavity. They attached to cortical fibers of the vitreous or floated in the vitreous cavity, and had a mobility. They had a various size, shape, and existed anywhere. They were present at 3 days initially and decreased in size and number as time goes by. Group 1 had the clear oil-drop residues in 11 eyes of 29 eyes, but Group 2 in 5 eyes of 24 eyes. Eyes in Group 2 had less residues in number. Conclusions: The clear oil-drop residues can be observed after IVTA and decanting decreased them after IVTA significantly.

기초과학연구논문집 - 1993 년 연구실적편 - / 물리학 : 비정질 Ge30S70 박막에 대한 열자극 전류 피크들의 기원

김화민(Hwa Min Kim),이병로(Byung Roh Rhee),김태만(Tae Man Kim),장현범(Hyun Bum Jang),이광배(Kwang Bae Lee) 대구가톨릭대학교 자연과학연구소 1993 기초과학연구논문집 -연구실적편- Vol.1993 No.-

RF - Magnetron Sputtering에 의하여 ITO 유리 위에 성장된 SrTiO₃ 박막의 열처리 특성

김화민(Hwa-Min Kim),이병로(Byung-Rho Rhee) 한국진공학회(ASCT) 2001 Applied Science and Convergence Technology Vol.10 No.4

SrTiO₃ 박막의 미세구조와 광학적 및 유전적 특성에 대한 열처리 효과들이 조사되었다. SrTiO₃ 박막은 RF-마그네트론 스퍼터링 방법에 의하여 상온의 ITO 유리 위에 성장되었으며, 성장된 박막들은 산소 분위기의 여러 온도에서 열처리되었다. X-선 회절 패턴을 분석한 결과 상온에서 제작된 as-deposited 박막은 비정질 상태로 나타났으며, 450-600℃에서 열처리한 시료에서는 pyrochlore 구조의 결정 피크들이 우세하게 관측되었다. 그리고 650℃에서 열처리한 시료에서는 perovskite 구조가 우세하게 나타나는 것이 관측되었다. 특히 650℃에서 열처리한 시료의 경우는 박막의 미세 결정구조 변화와 더불어 광학적 띠간격이 크게 변하는 것이 광투과도 측정으로부터 관측되었다. 그리고 600℃에서 열처리된 시료의 경우는 272℃에서 상전이 피크가 관측되는 반면, 650℃에서 열처리된 시료에서는 310℃ 부근에서 유전 분산이 관측되었다. Microstructural, optical and dielectric properties of SrTiO₃ thin films were investigated. These films were deposited on the ITO glasses by rf-magnetron sputtering at room temperature and subequently heat treated in O₂ atmosphere at various temperatures. It has been found from X-ray diffraction patterns that as-deposited films prepared at room temperature are amorphous, while the films heat treated at temperature range of 400~600℃ reveal the structure of pyrochlore. On the other hand, the structure of perovskite is dominantly observed in the films heat treated at temperatures over 650℃ in which the drastic changes of optical band gap and dielectric constant are observed. In addition, the phase transition peak is observed at 272℃ in the films heat treated at 600℃, while the dielectric dispersion is observed at near 310℃ in the films heat treated at 650℃.

유리체강내 트리암시놀론 주입술 직후의 안압변화와 안구마사지 효과

성현경,이정민,박영숙,이병로,Hyun Kyung Seong,Jeong Min Lee,Young Sook Park,Byung Ro Lee 대한안과학회 2007 대한안과학회지 Vol.48 No.6

Purpose: We determined immediate natural course of intraocular pressure (IOP) at different time points after intravitreal injection of triamcinolone acetonide (IVTA), and evaluated the effect of preoperative ocular massage to lower the immediate IOP spike after IVTA. Methods: This prospective randomized comparative case-series study comprised sixty three eyes of 60 patients with macular edema. Thirty three eyes of 28 patients underwent IVTA (group A), and thirty eyes of 27 patients underwent IVTA with preoperative ocular massage (group B). Anterior chamber paracentesis was not performed in any of the eyes. The IOPs before and after massage, and the IOPs after IVTA (immediately, 10 minutes, 20 minutes, 30 minutes, and 1 hour, 2 hours after IVTA) were measured, respectively. Results: Mean IOP reached a significant peak immediately after IVTA, and rapidly declined at 10 minutes, and then normalized after 20 minutes. Although Mean IOP was significantly lowered preoperatively by ocular massage, the IOP increment at any time point after IVTA was not significantly different between two groups. Conclusions: The significant IOP spike immediately after IVTA was rapidly normalized over 20 minutes. Preoperative ocular massage was not significantly effective in diminishing the immediate IOP elevation and its persistence after IVTA.

정상안 및 황반 질환에서 스펙트럼 영역 빛간섭단층촬영(3D-OCT 1000)의 황반 두께 및 부피 반복성

문상원,이정민,송유미,조희윤,이병로,Sang Won Moon,Jung Min Lee,You Mi Song,Hee Yoon Cho,Byung Ro Lee 대한안과학회 2010 대한안과학회지 Vol.51 No.4

Purpose: To evaluate the repeatability of macular thickness and total macular volume measurements made using spectral domain optical coherence tomography (OCT) in normal subjects and subjects with macular disease. Methods: Among a total of 108 subjects, there were 50 normal subjucts, 20 patients with diabetic macular edema, 10 patients with retinal vein occlusion, 15 patients with age-related macular degeneration, and 13 subjects with other conditions. Two serial macular measurements were obtained from each subject by a single experienced examiner using spectral domain OCT. The repeatability of the measurements was evaluated by comparing two consecutive foveal and perifoveal thickness measurements and total macular volume measurements. The intraclass correlation coefficient was also calculated to evaluate the repeatability of measurements made in normal and macular disease subjects. Result: Spectral domain OCT measurements of macular thickness and macular volume were found to be consistent. Measurements of normal subjects were the most consistent, followed by measurements of patients with age-related macular degeneration, retinal vein occlusion, and diabetic macular edema. Conclusions: Although measurements made using spectral domain OCT were repeatable across all subjects, they were more consistent in normal subjects than in patients with macular disease. The differences in repeatability should be considered in the context of diseased pathologic anatomy. Physicians should remain cautious when using these measurements for clinical evaluation. J Korean Ophthalmol Soc 2010;51(4):524-531