핵의학의 세계, 생명을 살리는 소중한 방사선

최원석,Choi, Won-Seok 한국정보통신기술협회 2011 TTA저널 Vol.133 No.-

영화 속에 등장하는 방사선은 평범한 파충류를 거대한 괴물 고질라로 만들거나 사람을 녹색 괴물 헐크로 만들어 버린다. 또한 언론에 비친 방사선은 마치 '살인 광선'처럼 우리 주변에서 가장 멀리해야할 것으로 비춰지고 있다. 최근의 한 드라마에서는 국익을 위해 신형 원자로 전문가를 서로 납치하기 위해 정보기관들 끼리 치열한 첩보전을 벌이는 내용이 나오기는 했지만 여전히 방사선에 대한 이미지는 부정적이다. 하지만 알려진 것과 달리 방사선은 수많은 사람의 목숨을 살리는 '생명의 빛'이기도 하다. 그렇다면 방사선이 어떻게 생명을 살리는데 도움을 줄 수 있는 것일까?

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

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.

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.

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.

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.

PECVD로 합성한 다이아몬드상 카본박막의 전기적 특성

최원석,박문기,홍병유,Choi, Won-Seok,Park, Mun-Gi,Hong, Byung-You 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.11

In addition to its similarity to genuine diamond film, diamond-like carbon (DLC) film has many advantages, including its wide band gap and variable refractive index. In this study, DLC films were prepared by the RF PECVD (Plasma Enhanced Chemical Vapor Deposition) method on silicon substrates using methane ($CH_4$) and hydrogen ($H_2$) gas. We examined the effects of the RF power on the electrical properties of the DLC films. The films were deposited at several RF powers ranging from 50 to 175 W in steps of 25 W. The leakage current of DLC films increased at higher deposition RF power. And the resistivities of DLC films grown at 50 W and 175 W were $5\times10^{11}$ ${\Omega}cm$ and $2.68\times10^{10}$ ${\Omega}cm$, respectively.

Orthodontic Distal Movement of the Abutment Premolar to the Posterior Edentulous Area

최원석,Choi, Won-Seok Korean Academy of Esthetic Dentistry 2000 Journal of the Korean Academy of Esthetic Dentistr Vol.9 No.1

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.