산소 분압에 따라 전자빔 증착법으로 제작된 TiO₂ 박막의 구조적.광학적 특성

최원석,김장섭,정종민,한성홍,김의정,이충우,주종현,Choi, Won-Seok,Kim, Jang-Seob,Jung, Jong-Min,Hahn, Sung-Hong,Kim, Eui-Jung,Lee, Chung-Woo,Joo, Jong-Hyun 한국광학회 2007 한국광학회지 Vol.18 No.2

전자빔 증착법을 이용하여 산소 분압에 따라 $TiO_2$ 박막을 제작하고, 열처리 온도에 따른 박막의 구조적 특성과 광학적 특성을 분석 하였다. $TiO_2$ 박막들의 물리적 특성은 주입된 산소량에 의존하였다. 주입된 산소량이 증가 할수록 상전이 온도가 높아지고, 가시광선 영역에서 $TiO_2$ 박막의 투과율이 증가하였다. 그리고 주입된 산소량이 작은 경우, $700^{\circ}C$에서 $1100^{\circ}C$로 열처리 후 $TiO_2$ 박막의 흡수단 이 좀더 장파장으로 이동하였다. We prepared $TiO_2$ thin films by electron-beam evaporation at various oxygen pressures, and investigated their optical and structural properties as a function of the annealing temperature. The physical properties of the $TiO_2$ thin films depend upon the injection oxygen content. With the increased injection of oxygen, the phase transformation temperature and the transmittance of $TiO_2$ thin films in the range of visible wavelength were increased. For low injection of oxygen, the absorption edges of $TiO_2$ thin films were more red-shifted when annealed at temperatures from $700^{\circ}C$ to $1100^{\circ}C$.

훈연공정을 첨가하여 제조한 발아콩 청국장의 품질특성

최원석,박화영,최웅규,Choi, Won-Seok,Park, Hwa-Young,Choi, Ung-Kyu 한국식품영양학회 2015 韓國食品營養學會誌 Vol.28 No.3

The aim of this study is to investigate the changes in the quality characteristics of cheonggukjang made with germinated soybeans, which is produced by the addition of a smoking process. The L value of smoked cheonggukjang made with germinated soybeans (SCGS) was higher than that of non-smoked cheonggukjang made with non-germinated soybeans (NCNS) and non-smoked cheonggukjang made with germinated soybeans (NCGS). The a value of NCNS was the highest, followed by NCGS and SCGS. The b and ${\Delta}T$ values had a similar tendency compared with the L value. The amino acids in NCGS were significantly decreased compared with NCNS, whereas no remarkable difference in amino acid content was observed between NCGS and SCGS. The moisture content of NCGS ($61.9{\pm}0.9%$) was increased by more than 8% compared with that of NCNS ($53.3{\pm}0.7%$). The moisture content of SCGS was significantly decreased compared with NCGS, whereas the moisture content of SCGS was higher than that of NCNS. The pH of SCGS was significantly the highest, followed by NCGS and NCNS. The viscous substance content of NCGS was significantly increased compared with that of NCNS. No remarkable difference in viscous substance content was observed between NCGS and SCGS. The number of aerobic bacteria in SCGS was significantly decreased compared with NCGS. The levels of total isoflavone in NCNS, NCGS, and SCGS were $1,573.9{\pm}62.5$, $1,759.1{\pm}65.8$, $1,738.0{\pm}68.1mg%$, respectively.

쌀밥의 조직감에 대한 기기적 측정값과 관능적 측정값의 상관관계 연구

최원석,Choi, Won-Seok 한국식품영양학회 2016 韓國食品營養學會誌 Vol.29 No.5

This study aimed to find the optimum instrumental test conditions for the Texture Profile Analysis (TPA) of cooked rice in order to predict the sensory texture attributes (hardness, adhesiveness, chewiness). Sensory evaluation was performed for three kinds of instant cooked rice with university students in their twenties and the results of the sensory evaluation were compared to instrumental TPA patterns. Using partial least squares regression, the instrumental TPA results at a cross-head speed of 1.0 mm/sec and a compression ratio of 70% proved to be an excellent predictor of the sensory attributes of hardness ($R^2=0.99$) and chewiness ($R^2=0.99$). The results at a cross-head speed of 0.5 mm/sec and compression ratio of 30% provided an excellent model for the prediction of sensory adhesiveness ($R^2=0.83$). In this experimental range, sensory hardness and chewiness showed a high correlation with instrumental TPA parameters (hardness, cohesiveness, adhesiveness, springiness, chewiness) with a high cross-head speed and compression ratio, while sensory adhesiveness showed a high correlation with the TPA parameters with a low cross-head speed and compression ratio.

백내장 수술 후 절개 방법에 따른 안압 변화 비교

최원석,신영주,김하경,이가영,Won Seok Choi,MD,Young Joo Shin,MD,PhD,Ha Kyoung Kim,MD,PhD,Kayoung Yi,MD,PhD 대한안과학회 2013 대한안과학회지 Vol.54 No.12

Purpose: In the present study we compared the intraocular pressure (IOP) after cataract surgery according to incisional techniques. <br /> Methods: Patients who underwent phacoemulsification with intraocular lens implantation were divided into 2 groups: clear corneal incision group (CC group), and scleral tunnel incision group (ST group). All complicated cases were excluded. IOP was measured preoperatively and at 1 week, 1, 3, 6, 12, 18 and 24 months after surgery.<br /> Results: Seventy-seven patients (100 eyes) were enrolled in the present study; CC group (28 patients, 33 eyes), ST group (49 patients 67 eyes). Preoperative IOPs in both groups were not significantly different (p = 0.908, student’s t-test). IOP in the CC group at 1 week after surgery significantly decreased 2.22 ± 2.57 mm Hg compared to preoperative IOP (p < 0.001, repeated-measures ANOVA with post hoc analysis), and the IOP of the ST group decreased 2.11 ± 2.50 mm Hg (p < 0.001, repeated-measures ANOVA with post hoc analysis). The lowered IOP was maintained for 24 months postoperatively. There was no significant difference in IOP change after surgery depending on incisional techniques (p = 0.848, repeated measures ANOVA).<br /> Conclusions: There may be no difference in IOP lowering effect after surgery depending on incisional techniques. <br /> J Korean Ophthalmol Soc 2013;54(12):1856-1861

화재에 대한 상식과 비상식

최원석,Choi, Won-Seok 한국정보통신기술협회 2010 TTA저널 Vol.132 No.-

2003년 2월 18일 대구 지하철에서 방화로 인해 사망 192명, 부상 148명이라는 대형 참사가 발생했다. 그로부터 5년 후인 2008년 2월 11일에는 국민들이 안타까운 눈길로 지켜보는 가운데 우리나라 국보 1호인 숭례문이 방화로 인해 역사 속으로 사라져버렸다. 이렇게 화재에 대한 악몽은 잊혀질 만하면 다시 찾아오지만 아직까지 이에 대한 경각심 제고나 예방을 위한 투자에는 큰 변화가 없는 것이 현실이다. 이는 대부분이 강 건너 불구경 하듯 화재가 남의 일이라고 느끼기 때문일 것이다. 하지만 불은 항상 주변에 있기에, 언제든 우리 또한 화재의 피해자가 될 수 있다. 따라서 누구나 화재에 대해 기본적인 상식을 갖출 필요가 있다.

생강의 첨가가 분쇄막창의 저장특성에 미치는 영향

최원석,최웅규,Choi, Won-Seok,Choi, Ung-Kyu 한국식품영양학회 2014 韓國食品營養學會誌 Vol.27 No.5

This study was conducted to investigate the effects of ginger addition (1%, 5% and 10%) on the quality of ground pork rectum. No significant difference in the pH was found between raw and cooked pork rectum during storage; however, the pH of cooked rectum was slightly lower than raw rectum. The TBA value of the cooked pork rectum (0.25 mg/kg) was higher than raw pork rectum (0.1 mg/kg). In addition, the TBA values of both raw and cooked pork rectum increased as storage progressed. The TBA value was found to decrease in proportion to the amount of ginger added. The volatile basic nitrogen (VBN) values also decreased with the addition of ginger. Consequently, considering that the initial stage of decomposition was 30~40%, it was determined that it would be desirable to consume the raw and cooked pork rectum within 4 and 6 days of storage at $5^{\circ}C$, respectively. Further, it was found that the addition of 10% ginger could extend the storage period beyond the 4 days at $5^{\circ}C$. 신선한 암퇘지의 막창부위에 지방을 제거하고 파쇄기로 잘게 부수어 가열하지 않은 것과 $100^{\circ}C$의 autoclave에서 10분간 가열한 것에 분쇄한 생강을 1, 5 및 10%가 되게 첨가하여 polyethylene film으로 1차 포장한 후 알루미늄 호일로 2차 포장한 다음 $5^{\circ}C$에서 보관하면서 품질의 변화를 관찰하였다. 저장 중 pH는 첨가구 사이의 유의적인 차이를 나타내지 않았으나, 가열한 막창이 다소 낮은 값을 나타내었다. TBA가는 각각 0.1 mg/kg과 0.25 mg/kg으로 가열 막창이 생막창보다 높은 값을 나타내었으며, 두 처리구에서 모두 생강의 첨가가 TBA-value의 상승을 억제시켜 저장성을 연장시키는 것을 확인할 수 있었다. 휘발성 염기질소의 함량은 생강의 첨가로 감소하였으며, 30~40 mg%의 초기부패 판정기준을 고려할 때 생막창은 $5^{\circ}C$에서 4일, 가열막창은 6일 이내에 소비하는 것이 바람직할 것으로 판단되었다. VBN 함량을 기준으로 10% 생강의 첨가는 가열막창의 저장기간을 4일 가량 연장시킬 수 있는 것으로 확인되었다.

극초단 펄스 레이저를 사용한 유리 내부의 필라멘테이션에 대한 실험적 연구

최원석,윤지욱,김주한,최지연,장원석,김재구,최두선,황경현,조성학,Choi, Won-Suk,Yoon, Ji-Wook,Kim, Joohan,Choi, Jiyeon,Chang, Won-Seok,Kim, Jae-Goo,Choi, Doo-Sun,Whang, Kyoung Hyun,Cho, Sung-Hak 한국레이저가공학회 2013 한국레이저가공학회지 Vol.16 No.1

We have successfully formed filament inside of a transparent soda-lime glass using a Ti:sapphire based femtosecond laser. To make filament form, keeping the laser intensity higher than critical intensity is essential. Also each of the machining parameters plays an important role for the formation of filament. In this paper, we study what parameter can possibly influence for formation of filament, and we introduce an application using filamentation by femtosecond laser for transparent material.

Fetal Bovine Serum을 포함한 세포 배양액에 담근 Indium Tin Oxide 전극 계면의 전기화학적 특성

최원석,조성보,Choi, Won Seok,Cho, Sungbo 대한의용생체공학회 2013 의공학회지 Vol.34 No.1

For the biocompatibility test of implantable devices or for the sensitivity evaluation of biomedical sensors, it is required to understand the mechanism of the protein adsorption and the interaction between the adsorbed proteins and cells. In this study, the adsorption of proteins in a cell culture medium with fetal bovine serum onto an indium tin-oxide electrode was characterized by using linear sweep voltammetry and impedance spectroscopy. We immersed the fabricated ITO electrodes in the culture medium for 30, 60, or 90 min, and then measured the electrochemical properties of electrodes with 10 mM $Fe(CN){_6}^{3-/4-}$ and 0.1 M KCl electrolyte. With an increase of contacting time, the anodic peak current was decreased and the charge transfer resistance was increased. However, both parameters were recovered to the values before contact with the medium after the treatment of Trypsin/Ethylenediaminetetraacetic acid hydrolyzing proteins.

LC 공진형 압력 센서를 이용한 돼지 경골 동맥의 실시간 혈압 측정

최원석,김진태,정연호,Choi, Won-Seok,Kim, Jin-Tae,Joung, Yeun-Ho 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.6

We have developed an implantable wireless sensor for real time pressure monitoring of blood circulation system. MEMS (micro-electro-mechanical system) technology was adopted as a sensor development method. The sensor is composed of photolithographically patterned inductors and a distributed capacitor in gap between the inductors. A resulting LC resonant system produces its resonant frequency in range of 269 to 284 MHz at 740 mmHg. To read the resonant frequency changed by blood pressure variation, we developed a custom readout system based on a network analyzer functionality. The bench-top testing of the pressure sensors showed good mechanical and electrical functionality. A sensor was implanted into tibial artery of farm pig, and interrogated wirelessly with accurate readings of blood pressure. After 45 days, the sensor's electrical response and histopathology were studied with good frequency reading and biocompatibility.

AMOLED 제조공정에 사용되는 Fine Metal Mask 용 얇은 Invar 합금의 진동자를 이용한 펨토초 레이저 응용 홀 드릴링

최원석,김훈영,신영관,최준하,장원석,김재구,조성학,최두선,Choi, Won-Suk,Kim, Hoon-Young,Shin, Young-Gwan,Choi, Jun-ha,Chang, Won-Seok,Kim, Jae-Gu,Cho, Sung-Hak,Choi, Doo-Sun 한국금형공학회 2020 한국금형공학회지 Vol.14 No.3

One of display trends today is development of high pixel density. To get high PPI, a small size of pixel must be developed. RGB pixel is arranged by evaporation process which determines pixel size. Normally, a fine metal mask (FMM; Invar alloy) has been used for evaporation process and it has advantages such as good strength, and low thermal expansion coefficient at low temperature. A FMM has been manufactured by chemical etching which has limitation to controlling the pattern shape and size. One of alternative method for patterning FMM is laser micromachining. Femtosecond laser is normally considered to improve those disadvantages for laser micromachining process due to such short pulse duration. In this paper, a femtosecond laser drilling for thickness of 16 ㎛ FMM is examined. Additionally, we introduce experimental results for controlling taper angle of hole by vibration module adapted in laser system. We used Ti:Sapphire based femtosecond laser with attenuating optics, co-axial illumination, vision system, 3-axis linear stage and vibration module. By controlling vibration amplitude, entrance and exit diameters are controllable. Using vibrating objective lens, we can control taper angle when femtosecond laser hole drilling by moving focusing point. The larger amplitude of vibration we control, the smaller taper angle will be carried out.