• 한국패류학회지
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• 제27권4호
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• pp.317-322
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• 2011

본 연구는 북방전복 (H. discus hannai) 의 겨울철 저수온으로 발생하는 폐사원인 규명을 위한 생리학적인 반응을 조사하기 위하여 수온 $12^{\circ}C$를 대조구로 $7^{\circ}C$ 및 $4^{\circ}C$의 실험구를 설정하고 10일간에 걸쳐 생존율, 항산화효소의 활성 및 총 단백질 농도를 측정하였다. 그 결과 $7^{\circ}C$ 저수온 실험구에서는 SOD 활성 및 총 단백질 농도가 대조구와 차이를 나타내지 않았으며 생존율은 90.8%를 나타내었다. 반면에 $4^{\circ}C$ 저수온 실험구에서는 SOD 활성은 노출직후에 급격히 상승하여 12시간째까지 대조구보다 유의적으로 높게 나타났다. 또한 총 단백질 농도에 있어서는 24시간째부터 실험종료 시까지 대조구보다 유의적으로 높게 나타났으며, 생존율은 3일째 10마리의 폐사를 시작으로 10일째 전 개체가 페사하였다. 이상의 결과로 북방전복 (H. discus hannai) 은 $7^{\circ}C$의 저수온 실험구에서는 다양한 생리적 기작을 이용하여 생존이 가능한 반면에 $4^{\circ}C$의 저수온 실험구에서는 생리적 순응반응을 나타내고 있으나 방어기작의 한계를 벗어나 생존이 불가능하다고 추정된다.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.660-671
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• 2003

A chemical investigation of Peucedanum praeruptorum has resulted in the isolation of 3 khellactone derivatives, which have inhibitory effects on melanogenesis in B16 mouse melanoma cell lines. The khellactone derivatives were isolated from the crude extract of the roots of Pecedanum praeruptorum by a combination of adsorption chromatography and HPLC. The structures of isolated compounds were identified as 3', 4'-diangeloyl-cis-khellactone, 3'-angeloyl-4'-senecioyl-cis-khellactone and, 3', 4'-disenecioyl-cis-khellactone by $^1$H NMR, $^{13}$ C NMR and mass spectral studies and by comparisons of spectral data with reported literatures. These khellactone derivatives can be a good candidate for new skin whitening agent due to its strong inhibitory activity and safety.

• 한국세라믹학회지
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• 제50권6호
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• pp.402-409
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• 2013

The objective of this study was to develop a synthesis process for ${\beta}$-SiC powders to reduce the synthesis temperature and to control the particle size and to prevent particle agglomeration of the synthesized ${\beta}$-SiC powders. A phenol resin and TEOS were used as the starting materials for the carbon and Si sources, respectively. $SiO_2$-C hybrid precursors with various C/Si mole ratios were fabricated using a conventional sol-gel process. ${\beta}$-SiC powders were synthesized by a carbothermal reduction process using $SiO_2$-C hybrid precursors with various C/Si mole ratios (1.6 ~ 2.5) fabricated using a sol-gel process. In this study, the effects of excess carbon and the addition of Si powders to the $SiO_2$-C hybrid precursor on the synthesis temperature and particle size of ${\beta}$-SiC were examined. It was found that the addition of metallic Si powders to the $SiO_2$/C hybrid precursor with excess carbon reduced the synthesis temperature of the ${\beta}$-SiC powders to as low as $1300^{\circ}C$. The synthesis temperature for ${\beta}$-SiC appeared to be reduced with an increase of the C/Si mole ratio in the $SiO_2$-C hybrid precursor by a direct carburization reaction between Si and excess carbon.

• 대한디지털의료영상학회논문지
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• 제11권1호
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• pp.21-26
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• 2009

In operation room, the use of the C-arm unit is increasing. So, the radiation dose of the person who work in operation room was even more increased than before. Thus, this study is shown the measurement of expose dose and the way for decrease of the radiation dose by using the C-arm unit. The experiment was performed with the C-arm unit and used a phantom which is similar to tissue of the human body and fluoro-glass dosimeter for dose measurement. The expose dose were measured by the tube position(over tube, under tube) of the C-arm unit, distance(50, 100$\sim$200cm), direction(I, II, III, IV), runtime(1min, 3min), wearing of the apron. The radiation dose was decreased twice and three times at under tube rather than over tube. The I direction was measured 20$\sim$30% more than the others. The biggest expose dose is 50cm from center on distance. The expose dose is decreased to far from center. In case of Wearing of the apron, the radiation dose was decreased 60$\sim$90% by the distance. But there weren't change of the radiation dose by C-arm tube position. In present, by increasing the usage of the C-arm unit, the radiation dose is inevitable. So, this study recommends us to use the under tube of the C-arm unit. Also, Wearing of the apron is required for minimum of the radiation exposure.

• 한국식품영양학회지
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• 제31권4호
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• pp.457-463
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• 2018

In this study, we analyzed the protective effects of the vitamin C in the streptozotocin (STZ)-induced apoptosis using the SH-SY5Y, a neuroblastoma cell line. The cells were pretreated with the vitamin C ($100{\mu}g$) for 30 min, followed by the 24-hr treatment with the 2.5-mM STZ. The cell-viability assay using the Cell Counting Kit (CCK)-8 revealed the cell-survival rate increased by 15% following the vitamin-C pretreatment compared to the STZ-only treatment. Moreover, we conducted the western-blot analysis to determine the protective effect of the vitamin C regarding the apoptosis. Compared to those in the STZ-only-treatment group, the p-ERK and Bcl-2 expressions increased in the vitamin-C-pretreatment group, whereas the p-JNK and Bax expressions decreased. The vitamin-C pretreatment increased the expression of the SOD-1, an antioxidant enzyme, by more than 30%, indicating its protective role in the STZ-induced oxidative stress. Also, we found both the intrinsic- and extrinsic-pathway mechanisms of the STZ-induced apoptosis. The results of this study $s{\mu}ggest$ vitamin C may help prevent the neurodegenerative diseases.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2007년도 제33회 하계학술대회 초록집
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• pp.337-337
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• 2007

• JSTS:Journal of Semiconductor Technology and Science
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• 제4권2호
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• pp.88-93
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• 2004

We, for the first time, present novel test patterns and conclusive on-chip data indicating that the variation of coupling capacitance, ${\Delta}C_C$ by crosstalk can be larger than static coupling capacitance, $C_C$. The test chip is fabricated using a generic 150 nm CMOS technology with 7 level metallization. It is also shown that ${\Delta}C_C$ is strongly dependent on the phase of aggressive lines. For antiphase crosstalk ${\Delta}C_C$ is always larger than $C_C$ while for in-phase crosstalk $D_{\Delta}C_C$is smaller than $C_C$.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
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• pp.711-711
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• 2005

• 한국세라믹학회지
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• 제50권6호
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• pp.410-415
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• 2013

$ZrB_2$-SiC ceramics are fabricated via hot pressing with different ratios of submicron or nano-sized SiC in a $ZrB_2$-20 vol%SiC system, in order to examine the effect of the SiC size ratio on the microstructures and physical properties, such as thermal conductivity, hardness, and flexural strength, of $ZrB_2$-SiC ceramics. Five different $ZrB_2$-SiC ceramics ($ZrB_2$-20 vol%[(1-x)SiC + xnanoSiC] where x = 0.0, 0.2, 0.5, 0.8, 1.0) are prepared in this study. The mean SiC particle sizes in the sintered bodies are highly dependent on the ratio of nano-sized SiC. The thermal conductivities of the $ZrB_2$-SiC ceramics increase with the ratio of nano-sized SiC, which is consistent with the percolation behavior. In addition, the $ZrB_2$-SiC ceramics with smaller mean SiC particle sizes exhibit enhanced mechanical properties, such as hardness and flexural strength, which can be explained using the Hall-Petch relation.

• 대한방사선치료학회지
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• 제31권1호
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• pp.43-49
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• 2019

목 적: 움직이는 장기에 취약한 Pencil Beam Scanning(PBS)을 보완하기 위해 고안된 Layered Rescanning PBS 기법을 Moving Phantom에 적용하여 Single Scan PBS와 선량비교를 통해 Homogeneity를 비교해 본다. 대상 및 방법: Matrix X(IBA, Belgium)와 Moving Phantom(standard imaging, USA)을 이용하였다. 가상의 tumor $10{\times}10{\times}5cm$에 AP 방향에서 200 cGy의 선량을 조사하였다. 치료계획은 single scan PBS, rescan 4, 8, 12회 총 4가지로 하였고 각 치료계획별로 3번씩 반복 측정하였다. 측정 시 Moving Phantom의 호흡주기는 한 cycle당 4초로 설정 후 S-I 방향 움직임 2 cm으로 설정하였다. 추가로 beam on time을 측정하였다. 결 과: PTV 내에서 $D_{max}$의 평균값은 single scan, 4, 8, 12회 rescan 순서로 각각 $246.47{\pm}18.8cGy$, $223.43{\pm}8.92cGy$, $222.47{\pm}7.7cGy$, $213.9{\pm}6.11cGy$ $D_{min}$의 평균값은 각각 $165.53{\pm}4.32cGy$, $173.13{\pm}11.94cGy$, $184.13{\pm}8.04cGy$, $182.67{\pm}4.38cGy$으로 $D_{mean}$ $192.77{\pm}6.98cGy$, $196.7{\pm}4.01cGy$, $198.17{\pm}4.96cGy$, $195.77{\pm}3.15cGy$으로 측정되었다. 그리고 rescan 횟수가 늘어날수록 Homogeneity Index가 1에 가까워졌으며, beam on time은 평균 2분 15초, 3분 15초, 4분 30초, 5분 37초로 rescan 횟수가 증가할수록 치료시간이 증가되었다. 측정하는 과정에서 MU가 낮은 선량 layer에서는 설정한 rescan 횟수만큼 실제로 rescan하지 못하는 문제점이 발견되었다. 결 론: 장기 움직임이 있는 종양 치료 시 Layered Rescanning PBS을 적용했을 때 single scan PBS보다 균일한 선량분포를 확인할 수 있었다. 그리고 rescan 횟수가 증가할수록 균일한 선량분포를 보였다. single scan PBS와 12회 Layered rescanning 비교 시 HI 수치가 0.32 향상되었다. 추후 연구를 통하여 호흡동조 방사선치료가 불가능환자에게 적용이 가능할 것으로 사료된다.