• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.149.1-149.1
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• 2014

전자총의 방출전류량과 소스크기, 그리고 방출 각전류밀도(angular current density)를 측정함으로서 얻어지는 전자총의 휘도(brightness)는 대물렌즈의 수차와 더불어 전자현미경의 성능을 좌우한다. 국내업체의 전자현미경은 대부분 상대적으로 휘도가 낮지만 작동압력이 10-5 Torr의 이하여서 제작과 사용이 용이한 텅스텐 필라멘트 열전자총을 채용하고 있다. 주사전자현미경의 성능을 좌우하는 프로브 크기와 전류량은 광학계의 배율과 전자총의 휘도에 의해서 결정되며, 설계시 전자현미경의 사양을 결정하기 위해서는 전자총의 휘도 측정이 필수이다. 한국표준과학연구원에서는 국내에서 생산되는 전자현미경용 열전자총의 휘도를 측정하기 위해, 전자총의 방출 각전류밀도와 소스 크기를 측정할 수 있는 전자총 휘도 측정 시스템을 개발하고 있다. 본 발표에서는 개발중인 시스템의 측정 원리를 기술한다. 또한 외부 자기장에 의한 교란을 방지하기 위해 연자성 재료인 연강으로 제작한 진공챔버의 진공특성을 보고한다.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.68-75
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• 2008

Space radiation environments depend on satellite mission orbit, period, and date, and it can be predicted by simulation. Total Ionizing Dose(TID) can be predicted by Dose-depth Curve which only inform the dose level depending on the shielding thickness. So detail effective shielding analysis considering real structure is necessary to predict part level TID. For this purpose, program is developed to calculate shielding thickness distribution by structure modeling and ray trace from certain point in the structure. Finally TID at certain point in the 3-dimensional structure can be calculated by integration of shielding distribution result and dose-depth curve data. Using this program, TID is analyzed at part level certain point by modeling of equipment box structure in the satellite.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.39.2-39.2
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• 2009

지자기 폭풍이 발생할 동안 중위도 전리권 전자밀도 변화의 가장 큰 특징은 양전리권 폭풍 또는 음전리권 폭풍이다. 양전리층 폭풍은 정상적인 경우보다 전자밀도가 증가하는 것으로 정의되는데 적도방향 중성바람에 의한 극지방 전자밀도의 중위도로의 이동으로 설명된다. 음전리권 폭풍은 F2 층 고도의 O/N2 증가에 의한 전자소멸로 전자밀도가 낮아지는 것으로 알려져 있다. 우리는 지상 GPS 총전자량 자료와 이를 이용한 전리권 토모그래피 모델 결과, 그리고 이온존데 관측에 나타난 한반도 상공의 전리층 폭풍 양상을 제시하고 토의할 것이다.

• Clinical and Experimental Pediatrics
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• v.46 no.9
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• pp.876-882
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• 2003

Purpose : To find out the myocardial protective effect of cardioxane for the myocardial damage by doxorubicin. Methods : Using Eighteen rabbits(2.0-3.2 kg), doxorubicin($30mg/m^2$) was injected intravenously once a week in group I(12 rabbits) and cardioxane($600mg/m^2$) was injected at 20-30 minutes before doxorubicin administration in group II(6 rabbits). After this, we operated on the rabbits when the total cumulative dose of doxorubicin was reached at 210, 240, 270 and $300mg/m^2$ and observed the degree of myocardial damage with light and electronic microscope. Results : In group I, rabbits with less than $210mg/m^2$ of total cumulative dose of doxorubicin, there was no definite myocardial damage but with $240mg/m^2$, focal degenerative change was observed and with $300mg/m^2$, severe degenerative change was detected with light microscopic examination. With electronic microscope, rabbits with less than $180mg/m^2$ of total cumulative dose of doxorubicin in group I, there was no evidence of myocardial damage. In $210mg/m^2$, focal degenerative change was detected. With $240mg/m^2$, degenerative change was much more advanced and with $300mg/m^2$, severe degenerative change was detected. In group II, no definite myocardial damage was observed even though the total cumulative dose of doxorubicin reached $300mg/m^2$, but with $360mg/m^2$, there was a focal area where myocardial fibers were somewhat decreased, but it's difficult to say whether these decrement were due to adriamycin in the electronic microscopic examination. Conclusion : Cardioxane have a good protective effect for the doxorubicin induced cardiomyopathy and it will be used safely in pediatric cancer patients.

• Korean Journal of Poultry Science
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• v.38 no.2
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• pp.105-112
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• 2011

This study were investigated the effects of dietary supplementation of ground Kalopanax pictus leaves powder on pH, total phenol contents, DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, TBARS, WHC, shear force, meat color, sensory evaluation, and fatty acid composition of chicken meat. Broiler chicks were fed diets for five weeks containing 0% Kalopanax pictus leaves powder (Control), 0.5% Kalopanax pictus leaves powder (T1), 1.0% Kalopanax pictus leaves powder (T2), and 2.0% Kalopanax pictus leaves powder (T3). The pH and TBARS were significantly decreased by the supplementation of Kalopanax pictus leaves powder compared to the control (P<0.05). The total phenol contents and DPPH radical scavenging activity were significantly increased by the supplementation of Kalopanax pictus leaves powder compared to those of the control group (P<0.05), and especially, T3 was significantly (P<0.05) more effective in improving freshness compared to other treatment groups. The WHC and shear force were not significantly different. CIE $L^*$ and $a^*$ value of treatment groups (especially T3) showed significantly higher value compare to the control, however, no difference in the CIE $b^*$ values was observed among treatment groups. In fatty acid composition, linolenic acid of chicken meat was increased by the supplementation of Kalopanax pictus leaves powder than compared to those of the non-supplementation group. In conclusion, a supplementation of Kalopanax pictus leaves powder was effective in decreasing pH and TBARS, and increasing total phenol contents and DPPH radical scavenging activity.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.86-90
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• 2002

IT분야에 대한 정부의 각종 R&D사업 수행 시 과제 선정 및 연구결과에 대한 평가의 투명성, 객관성 및 효율성을 확보하여 사업의 신뢰성을 확보하고 성과를 제고하여야 한다. 1999년 대학기초연구지원 사업에 시범적으로 적용한 전자평가시스템 개발 내용과 그 결과를 위원회 평가와 비교 분석하였다. 1999년에 처음 시도한 전자평가시스템은 과제 제안자 관점에서는 과제접수가 용이하고, 과제 공고부터 결과 정리 시 소요되는 총 소요기간 단축으로 과제 선정을 조속히 확정 가능하여 대민 서비스 제고 차원에서 유용한 평가시스템으로 판단되며, 과제 관리 차원에서도 총 평가비용의 30% 정도의 예산절감 및 10배정도 업무량의 감소 효과를 주는 것으로 분석되었다. 이와 같은 결과를 바탕으로 전자평가시스템이 적용 가능한 사업을 발굴하여 점진적으로 확대 적용하는 것이 타당하며 향후 추진 과제로 산업체가 제안하는 과제내용이 제안자 동의 없이 외부로 유출 방지 등 검토가 필요하다.

• Journal of the Korean Applied Science and Technology
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• v.33 no.4
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• pp.693-697
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• 2016

In this study, the electron donating ability(EDA) and total polyphenol content of herbal wine were examined. The herbal wine was obtained from extract concentration to evaluate its functional properties. The herbal wine were screened for their potential antioxidant activities using test such as electron donating ability(EDA) and total polyphenol content. The electron donating ability(EDA) were $21.81{\pm}0.56$ in herbal wine 15% and $40.45{\pm}1.60$ in herbal wine 35%. As the extract concentration was increased the electron donating ability(EDA) were significantly increased(p<0.05). The total polyphenol contents were measures $113.89{\pm}1.79{\mu}g\;GAE/m{\ell}$ in herbal wine 15%, $274.24{\pm}0.71{\mu}g\;GAE/m{\ell}$ in herbal wine 35%. As the extract concentration was increased the total polyphenol contents were significantly increased(p<0.05). Also, the total polyphenol contents were measures $61.75{\mu}g\;GAE/m{\ell}$ in herbal wine, the higher.

• The Journal of Society for e-Business Studies
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• v.25 no.4
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• pp.125-141
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• 2020

Recent Studies emphasize the effect of investors attention, recognition and sentiment on the trading behavior of retail investors and stock price variation. In this study, we use Naver Trend to measure investors'attention and investigate the relation between investor attention and price synchronicity, total risk and systematic risk of stocks. Using various research methodologies such as portfolio analysis, fixed effect regression and dynamic panel analysis, we find consistent results. First, stock price synchronicity is increased with lager average search volume, but with less search variability. Second, both average search volume and its variability are positively related to total risk and beta of stocks. These results can be interpreted that search volume sharply increases only when stock-related event occurs.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.137.2-137.2
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• 2012

위성이 우주에서 노출되는 우주방사선 환경은 위성의 임무궤도 및 임무 기간에 따라 크게 달라진다. 지구 주위의 자기장에 의해 갇혀있는 양성자 및 전자의 환경은 고도에 따라 밀도 및 분포의 차이를 보인다. 특히 밴 앨런 밸트 내의 경계부분을 넘어서는 높은 고도에서의 방사선 입자별 노출 환경은 저궤도의 환경과는 구성 및 영향성이 크게 다르다. 본 논문에서는 전자 밸트 고도에서 운영되는 정지궤도 위성의 우주방사선 입자 환경을 분석하였다. 지구 자기장에 갇힌 입자, 태양입자 및 외부은하 입자 환경을 모델별로 분석하였으며 각 입자별 Flux 및 Fluence 스펙트럼을 이용하여 총 이온화 조사량과 중이온 스펙트럼을 도출하였다.

• Journal of Astronomy and Space Sciences
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• v.22 no.4
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• pp.537-558
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• 2005

This paper addresses the results of HAUSAT-2 radiation environment and effect analyses, including TID and SEE analyses. Trapped proton and electron, solar proton, galactic cosmic ray models were considered for HAUSAT-2 TID radiation environment analysis. TID was analyzed through total dose-depth curve and the radiation tolerance of TID for HAUSAT-2 components was verified by using DMBP method and sectoring analysis. HAUSAT-2 LET spectrum for heavy ion and proton were also analyzed for SEE investigation. SEE(SEU, SEL) analyses were accomplished for MPC860T2B microprocessor and K6X8008T2B memory. It was estimated that several SEUs may occur without SEL during the HAUSAT-2 mission life(2 years). Software Hamming Code EDAC has been implemented to detect and correct the SEU. In this study, all radiation analyses were conducted by using SPENVIS software.