• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.440-440
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• 2012

Nanomaterials have emerged as new building blocks to construct light energy harvesting assemblies. Size dependent properties provide the basis for developing new and effective systems with semiconductor nanoparticles, quantized charging effects in metal nanoparticle or their combinations in 2 and 3 dimensions for expanding the possibility of developing new strategies for photovoltaic system. As top-down approach, we developed a simple and effective method for the large scale formation of self-assembled Cu(In,Ga)$Se_2$ (CIGS) nanostructures by ion beam irradiation. The compositional changes and morphological evolution were observed as a function of the irradiation time. As the ion irradiation time increased, the nano-dots were transformed into a nano-ridge structure due to the difference in the sputtering yields and diffusion rates of each element and the competition between sputtering and diffusion processes during irradiation. As bottom-up approach, we developed the growth of CIGS nanowires using thermal-chemical vapor deposition (CVD) method. Vapor-phase synthesis is probably the most extensively explored approach to the formation of 1D nanostructures such as whiskers, nanorods, and nanowires. However, unlike binary or ternary chalcogenides, the synthesis of quaternary CIGS nanostructures is challenging because of the difficulty in controlling the stoichiometry and phase structure. We introduced a method for synthesis of the single crystalline CIGS nanowires in the form of chalcopyrite using thermal-CVD without catalyst. It was confirmed that the CIGS nanowires are epitaxially grown on a sapphire substrate, having a length ranged from 3 to 100 micrometers and a diameter from 30 to 500 nm.

• 한국정보통신학회논문지
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• 제20권12호
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• pp.2310-2316
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• 2016

본 논문에서는 격자 공정 중에 KrF 엑시머 UV 레이저 노출시간에 따른 광섬유 브래그 격자의 $Co^{60}$ 감마방사선 영향을 연구하였다. 광섬유 브래그 격자는 게르마늄이 첨가된 일반 광섬유를 이용하였으며, UV KrF 엑시머 레이저 노출시간(30, 60, 90, 120초)을 달리하여 제작하였다. 제작된 광섬유 브래그 격자에 106 Gy/min 선량률로 총 선량 34.3 kGy 감마선을 조사한 후 방사선에 의한 온도감도 계수와 브래그 파장 변화를 분석하였다. 실험결과를 통하여, 격자 공정을 위한 UV 레이저 노출시간이 광섬유 브래그 격자의 방사선 민감도에 큰 영향을 줄 수 있다는 것을 확인하였다. 레이저 노출조건 변화에 따른 방사선에 의한 광섬유 브래그 파장의 변화는 최대 50 % 이상의 차이를 보였다.

• 디지털융복합연구
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• 제12권6호
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• pp.433-438
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• 2014

본 연구는 흰쥐의 정소에 방사선을 조사하였을 때 시간이 경과함에 따라 나타나는 정소세포 및 정자의 변화를 현미경학적으로 얻은 영상을 기초로 영상처리에 의한 정량분석을 통하여 정자의 변화에 대한 결과를 정량화함으로써 더 정확하고 객관적인 결과를 얻고자 하는데 그 목적을 두고 있다. 연구에는 8주 수령의 흰쥐를 대상으로 하였으며, 6 MV의 X선을 1회 2 Gy를 전신 조사하였다. 총 30 마리의 흰쥐를 대상으로 방사선을 조사하지 않은 정상대조군과 실험군을 조사 즉시, 조사 2시간, 4시간, 8시간, 24시간 후에 각 실험군 마다 5마리의 정소를 각각 적출하였다. 적출 후 Periodic acid Schiff 염색을 시행하여 정상대조군과 실험군에서의 정소세포와 정자의 상태를 관찰하였다. 방사선조사 후 24시간까지, 정소세포수와 정자수가 점차 감소하는 것을 정성적 및 정량적으로 유의함을 확인하였다.

• 패션비즈니스
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• 제19권4호
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• pp.120-134
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• 2015

This study aimed to determine the physical properties of silk and nylon fabrics that are treated with persimmon juice in accordance with irradiation time of ultraviolet spectrum. Persimmon juice dyeing has the advantage of using the tannin component of the persimmon. Tannin plays an important role in inhibiting photodegradation of fibers or polymers. Among fibrous materials, silk and nylon are prone to deterioration by light. Hence, this study aimed to reduce these weaknesses of silk and nylon by applying persimmon juice treatment. We accordingly carried out investigation and experiments on ultraviolet irradiation, and physical characteristics of treated fabrics. The persimmon juice treatment process led to increased weight and thickness. In addition, the air permeability of silk fabric was increased, as compared to the control specimen; whereas, that of nylon fabric was decreased. Both drape stiffness and flex stiffness of silk and nylon tended to be high in textiles processed with persimmon juice treatment, as compared to the control textile. Peak load and elongation at peak load of untreated samples clearly decreased in both silk and nylon fabrics with the increase of ultraviolet irradiation time, while those of persimmon juice treated samples increased. Furthermore, ultraviolet blocking ratio measurement indicated that the fabric specimens treated with persimmon juice blocked U.V. spectrum better than the control specimen.

• 한국식품과학회지
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• 제22권3호
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• pp.290-295
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• 1990

감마선 조사(0, 2, 4kGy)에 따른 튀긴 닭고기 patty의 미생물 및 TBA가의 변화를 조사하기 위하여 닭고기 patty를 각각 $3{\pm}1^{\circ}C$ 와 $-10{\pm}1^{\circ}C$에서 저장하였다. 방사선 조사에 의하여 $3{\pm}1^{\circ}C$에 저장된 닭고기 patty의 품길 수명은 증가하였다(p<0.05). 대조구 1g당 미생물 총균 log 수가 6.5에 다다르는데 걸리는 시간은 22일인 반면 방사선 조사구는 40일이 걸렸으며 4kGy로 조사된 patty에서는 초기에 미생물이 발견되지 않았다. 조사선량 증가에 따라 gram-positive cocci의 미생물은 감소한 반면 2kGy와 4kGy로 조사된 시료에서는 각각 yeasts와 gram-negative rod 미생물이 현저했다. TBA가는 조사량과 저장기간이 증가함에 따라 증가하였다.

• 한국식품영양과학회지
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• 제11권4호
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• pp.53-59
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• 1982

감자의 장기안전저장법(長期安全貯藏法) 개발(開發)을 위하여 적정조사선량(適正照射線量)및 적정조사시기(適正照射時期)를 구명(究明)한 결과(結果)는 아래와 같다. (1) 품종간(品種間)에 차이(差異)는 있으나 수확후 $15{\sim}30$일(日) 사이에 방사선(放射線)을 조사(照射)할때는 12.5krad의 선량(線量)이 적당하고, 수확후 45일(日) 이후에 조사(照射)할때는 15krad 정도의 조사(照射)가 필요(必要)하며, 가급적 수확후 휴면기간(休眠期間)중 빨리 조사(照射)하는 것이 유리하다고 본다. (2) 적정조사선량(適正照射線量)에서의 조사구(調査區)는 무처리구(無處理區)에 비(比)해 물리적성질(物理的性質)이 우수(優秀)하였으며, 방사선조사(放射線照射) 후(後) 자연저온저장고(自然低溫貯藏庫)에 저장(貯藏) 함으로서 무처리구(無處理區)보다 저장기간(貯藏期間)을 4개월이상(個月以上) 연장시킬수 있었다.

• Preventive Nutrition and Food Science
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• 제7권1호
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• pp.57-61
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• 2002

Electron spin resonance (ESR) spectroscopy was used to investigate the effect of irradiation dose and storage time on the free radical concentrations in gamma-irradiated dried seasoning powder. Seasoning powders of dried squid flavor, shrimp flavors, kimchi flavor, spicy beef soup flavor and soy sauce flavor were irradiated with doses of 0, 1, 3, 5, 7 and 9 kGy at room temperature using a Co-60 irradiator. Characteristic signals of free radicals were observed in all the irradiated samples of this experimental while these signals were not detected in non-irradiated samples. Since the free radical concentrations linearly increased with the applied doses (1~9 kGy), highly positive correlation coefficients ($R^2$ = 0.9285~0.9965) were obtained between irradiation doses and free radical concentrations during all the storage times. Free radical concentrations of the irradiated flavored seasoning powder did not change even at 16 weeks of storage at room temperature, while those of dried squid, shrimp and spicy beef soup flavors decreased until 2 weeks of storage after irradiation with 5 kGy or over, and these of soy cause flavors slowly decreased until 8 weeks of storage after irradiation with 3 kGy or over. Although the free radical concentrations decreased with storage times, the characteristic signals of the irradiated seasoning powders of dried squid, shrimp, spicy beef and soy sauce flavors were observed even after 16 weeks of storage at room temperature.

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1470-1474
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• 2009

Thermal and photochemistry of methyl iodide ($CH_3I)\;adsorbed\;on\;D_2O$ ice film on Cu(111) at 100 K were studied using temperature-programmed desorption (TPD) time-of-flight mass spectrometry (TOF-MS), X-ray and ultraviolet photoelectron spectroscopies. On the basis of TPD, multilayer and monolayer $CH_3I$ molecules desorb from $D_2O$ ice layer at 120 and 130 K, respectively. Photo-irradiation at 100 K exhibits dramatic changes in the TPD and I $3d_{5/2}\;XPS\;of\;CH_3I$ on ice film, due to a dramatic dissociation of $CH_3I$. The dissociation is likely activated by solvated electrons transferred from the metal substrate during photo-irradiation. No other photo-initiated reaction products were found within our instrumental detection limit. During photo-irradiation, the $CH_3I$, $CH_3$ and I could be trapped (or solvated) in ice film by rearrangement (and self-diffusion) of water molecules. A newly appeared parent molecular desorption peak at 145 K is attributed to trapped $CH_3I$. In addition, the $CH_3$ and I may diffuse through ice and chemisorb on Cu(111), indicated by TPD and I $d_{5/2}$ XPS taken with photo-irradiation time, respectively. No molecular ejection was found during photo-irradiation at 100 K. The work functions for $CH_3I/Cu(111),\;D_2O/Cu(111)\;and\;CH_3I/D_2$O/Cu(111) were all measured to be about 3.9 eV, 1.0 eV downward shift from that of clean Cu(111).

• 대한방사선치료학회지
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• 제12권1호
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• pp.166-173
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• 2000

Angiopoietin-1(Ang-1) is a vasculogenic factor that signals through the endothelial cell-specific Tie2 receptor tyrosine kinase. We examined the effect of angiopoietin-1(Ang-1) on radiation-induced apoptosis in human umbilical vein endothelial cells(HUVECS) and receptor/second messenger signal transduction pathway for Ang-1's effect on HUVECs. The percent of apoptotic cells under control condition(0Gy) was $8.2\%$. Irradiation induced apoptosis was increased in a dose(1, 5, 10, and 15Gy)- and time 12, 24, 48 and 72hr)-dependent manner. The percent of apoptotic cells was approximately $34.9\%$ after 15 Gy of irradiation. Under these conditions, pretreatment with Ang-1's (50, 100, 200, and 400 ng/ml) inhibited irradiation-induced apoptosis in human umbilical vein endothelial cells in a dose-dependent manner. Two hundred ng/ml of Ang-1 inhibited approximately $55-60\%$ of the apoptotic events that occurred in the 10 Gy-irradiated cells. Pre-treatment with soluble Tie2 receptor, but not Tie1 receptor, blocked the Ang-1's antiapoptotic effects. Phosphatidylinositol 3'-kinase (P13-kinase) specific inhibitor, wortmanin and LY294002, blocked the Ang-1-induced antiapoptotic effect. Ang-1 promotes the survival of endothelial cells in irradiation-induced apoptosis through Tie2 receptor binding and P13-kinase activation. Pretreatment of Ang-1 could be beneficial in maintaining normal endothelial cell integrity during irradiation therapy.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2313-2318
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• 2003

By means of flexible forming processes in sheet metal manufacturing it is possible to produce parts of complex geometry within short manufacturing time. These procedures are suitable especially for prototyping or adjustment of deformation. Here formative procedures like laser forming are increasingly important, because they make the large-scale-like production of the prototypes with the required materials possible. High accuracy and reproducibility of the products is the precondition of the production. Due to the lack of a forming tool, complex geometries can hardly be manufactured within tolerances. To overcome this problem an automatic closed loop control system for the adjustment of deformations has been developed. An important element of the closed loop control system is the definition of a suitable irradiation strategy for laser forming. For the determination of the irradiation strategy a lot of influences must be taken into consideration from the field of material, geometry and laser. In this paper the improved closed loop control system and the development of an irradiation strategy for 4 mm deep buckles in an ALMgSi1 sheet will be represented. This system can be used e.g. in the automated adjustment of hail damage in car bodies or deformation by heat treatment.