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이석,양대식,박영제,신동호,허현도,이상훈,조삼주,임상욱,장지선,조광환,신헌주,김철용,Lee, Suk,Yang, Dae-Sik,Park, Young-Je,Shin, Dong-Ho,Huh, Hyun-Do,Lee, Sang-Hoon,Cho, Sam-Ju,Lim, Sang-Wook,Jang, Ji-Sun,Cho, Kwang-Hwan,Shin, Hun-Joo,Kim Korean Society of Medical Physics 2007 의학물리 Vol.18 No.1
호흡운동 조절 방사선치료 시 환자체표면 움직임을 추적하여 실시간 보정하고자 한다. 본 연구에서 사용한 시스템은 치료테이블에 기반을 둔 동 팬텀(CBMP, couch based computer-controlled motion phantom), 초음파 센서 및 제어, 구동, 분석 프로그램 등으로 구성하였다 동물실험 결과 호흡주기는 2.9초이었고, 호흡진폭은 6mm이었다. 실시간 체표면 추적시스템의 유용성 평가에 중요한 항목인 호흡운동 획득-보정간의 지연시간은 $2.34{\times}10^{-4}sec$ 초이어서 호흡운동 조절 방사선치료 시 사용할 수 있는 새로운 실시간 체표면 추적 기술의 임상적용에의 가능성을 확인할 수 있었다. Respiration sating radiotherapy technique developed In consideration of the movement of body surface and Internal organs during respiration, is categorized into the method of analyzing the respiratory volume for data processing and that of keeping track of fiducial landmark or dermatologic markers based on radiography. However, since these methods require high-priced equipments for treatment and are used for the specific radiotherapy. Therefore, we should develop new essential method whilst ruling out the possible problems. This study alms to obtain body surface motion by using the couch based computer-controlled motion phantom (CBMP) and US sensor, and to develop respiration gating techniques that can adjust patients' beds by using opposite values of the data obtained. The CBMP made to measure body surface motion is composed of a BS II microprocessor, sensor, host computer and stopping motor etc. And the program to control and operate It was developed. After the CBMP was adjusted by entering random movement data, and the phantom movements were acquired using the sensors, the two data were compared and analyzed. And then, after the movements by respiration were acquired by using a rabbit, the real-time respiration gating techniques were drawn by operating the phantom with the opposite values of the data. The result of analysing the acquisition-correction delay time for the data value shows that the data value coincided within 1% and that the acquistition-correction delay time was obtained real-time $(2.34{\times}10^{-4}sec)$. And the movement was the maximum movement was 6 mm In Z direction, In which the respiratory cycle was 2.9 seconds. This study successfully confirms the clinical application possibility of respiration gating techniques by using a CBWP and sensor.
가황시스템 변화가 배합고무의 가황반응속도 및 물리적 특성에 미치는 영향
이석,박남국,Lee, Seag,Park, Nam Cook 한국공업화학회 1999 공업화학 Vol.10 No.3
가황고무의 가황반응에 대하여 가황시스템 및 온도, 보강성충전제 첨가량 변화에 의한 반응속도상수 및 활성화에너지, 가교밀도 및 탄성상수, 가황특성 ($t_5,\;t_{90}$), 고무보강성 및 내마모성을 고찰하였다. 반응속도상수는 보강성충전제 첨가량, 가황시스템 및 가황반응온도에 대한 의존성이 크게 나타났으며, 반응온도에 따라 지수적으로 증가하였다. 활성화에너지는 가황시스템중 촉진제에 대한 황 비율이 높은 가황시스템에서 가장 작게 나타났으며, 보강성충전제 첨가량이 적을수록 작게 나타났다. 카본블랙 첨가량 변화는 고무보강성 및 내마모성에 직접적으로 영향을 미치고 있으나, 가황시스템 변화는 각기 다른 영향이 나타났다. 카본블랙 첨가량이 증가하면 모듈러스가 증가하고, 내마모성이 향상되며, 스코치시간이 짧아졌으나, 가교밀도 및 탄생상수는 감소하였다. 높은 가교밀도 및 탄성상수는 카본블랙 첨가량에 관계없이 촉진제에 대한 황 비율 0.73 (${\fallingdotseq}1$)에서 나타났으며, 스코치시간 ($t_5$)은 촉진제에 대한 황 비율 변화에 거의 영향을 받지 않는 것으로 나타났다. 빠른 최적가황시간 ($t_{90}$) 역시 촉진재에 대한 황 비율이 1에 가까운 조건 (=0.73)에서 나타났다. 가황조건별 배합고무의 등가 가황곡선계수는 카본블랙 첨가량에 관계없이 CC 시스템에 대해서는 0.96, SEC 및 EC 시스템에 대해서는 0.74로 나타났다. 한편 가황고무의 마모된 부피는 부과된 하중이 증가함에 따라 지수적으로 증가하였다. In this study, the reaction rate constant, activation energy, total crosslinking density, elastic constant, cure properties ($t_5,\;t_{90}$), modulus, and abrasion resistance of rubber compounds were investigated as a function of cure temperatures, cure systems and reinforcing filler loadings. Reaction rate constants showed strong dependence on thc carbon black loading, cure temperature and cure system, and increased sharply with increasing the reaction temperatures. The lowest activation energy was obtained in the efficient cure (EC) system which corresponds to the high level of sulfur to accelerator ratio, and the activation energy was decreased with decreasing the carbon black loadings. The change of carbon black loadings directly affects the modulus and abrasion resistance, but the change of cure system showed various effects on the rubber compounds. Increased carbon black loadings showed the high modulus, improved abrasion resistance and short scorch time but decrease in crosslinking density and elastic constant. Higher crosslinking density and elastic constant were shown in the EC cure system regardless of carbon black loadings, but scorch timc ($t_5$) was not affected by the change of the ratio of sulfur to accelerator. Rapid optimum cure time ($t_{90}$) were showen in the EC cure system. Also, the equivalent cure curve coefficient of rubber compound was 0.96 for conventional cure (CC) system, and 0.94 for semi-efficient cure (SEC) and EC system regardless carbon black loadings. As regarding the abrasion resistance, wear volume showed the logarithmic increase for the loaded weight.
이석,안중배,김진안,조홍근,김범수,허갑범,이현철,임승길,정윤석,조재용,라선영,정동운 대한내과학회 1994 대한내과학회지 Vol.47 No.3
Pheochromocytoma originates from chromaffin cells and occurs in the adrenal medulla in majority. About 10 percents of pheochromocytomas can occur in extra- adrenal sites, and anywhere along the fetal route of chromaffin tissues, Pheochromocytomas involving the urinary bladder are rare neoplasms which probably account for less than 0. 06% of all bladder tumors. A characteristic symptom complex due to increased catecholamine release in association with detrusor activity during micturition is often the essential element required for the diagnosis of this rare lesion. However, the diagnosis is often delayed for many years, because most physicians are unfamiliar with the symptoms, due to the rarity of this neoplasm. We report two cases of functioning pheochromocytoma of the urinary bladder with typical symptoms. The tumors of patients were explored transperitoneally and removed by partial cystectomy.
The Effect of Surface Activity of Carbon Black on Reinforcement and Kinetics of Vulcanization
이석,박남국,국승욱 전남도립대학교 1999 전남도립대학교 논문집 Vol.S No.-
NR/BR 및 NR/SBR 블랜드에 있어서 카본블랙의 표면활성이 고무의 보강성에 미치는 영향을 300% 모듈러서와 100% 모듈러스의 비율,가교밀도,반응속도 및 활성화 에너지를 통하여 조사하였다. 카본블랙 표면활성이 높은 경우가 교밀도와 결합고무량의 증가로 높은 보강효과를 나타내었다. 그러나 반응속도와 활성화 에너지에는 거의 영향이 없었다. NR/BR 블랜드가 NR/SBR 블랜드보다 BR의 높은 반응성에 기인되어 높은 속도상수를 나타내었다. 마지막으로 카본블랙의 표면활성은 고무의 보강과 물성에 어느 정도 영향을 미쳤는데 이는 카본블랙표면과 고무분자 사이의 상호작용이 변하기 때문에 기인된 현상이다.
이석,임용환,한윤봉 한국화학공학회 2007 화학공학의이론과응용 Vol.10 No.1
ZnO films were deposited on Si substrates by a two-step growth technique using atomic layer deposition (ALD). We investigated to improve the film quality depends on thickness of ZnO buffer layer. Surface morphology was investigated by atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The crystallinity and optical properties of the ZnO films were also investigated by X-ray diffraction (XRD) and photoluminescence (PL), respectively. ZnO films depending on the thickness of buffer layer showed the strongest ZnO (0002) diffraction peak and flat surface. The room temperature PL spectrum showed a strong NBE peak at 373nm. It was found that the thickness of ZnO buffer layer affects surface morphology, crystallinity and optical properties of ZnO films.