• 한국정보전자통신기술학회논문지
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• 제8권1호
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• pp.70-74
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• 2015

본 논문에서는 광대역 사각형 평면 모노폴 안테나의 복사 모드를 해석함으로써 사각형 평면 모노폴이 광대역 특성을 갖는 원리를 규명하고 대역폭 예측 공식을 제시한다. 사각형 평면 모노폴 안테나는, 설계와 제작이 용이한 장점으로 인하여, 기존의 원통 실린더형 모노폴을 대체하여 UWB(Ultra Wide Band) 및 다중 밴드용 안테나로서 많은 연구가 이루어지고 있다. 그러나 설계에 있어서 실린더형 모노폴의 설계 원리를 준용하고 있으며, 광대역이 실현되는 원리의 규명과 상측 대역의 주파수 범위를 예측할 수 있는 공식이 아직 발표되어 있지 않다. 본 연구에서 사각형 평면 모노폴은 주파수에 따라 상이한 이중 복사 모드를 가짐으로써 광대역 특성이 구현됨을 보였으며, 각 모드의 형성 원리에 근거하여 대역폭을 예측할 수 있는 공식을 제시하였다. 주파수 범위 예측 공식을 기존에 발표된 제작 결과에 적용하여 10 % 이내의 정확도가 얻어짐을 확인하였다.

• 한국의학물리학회지:의학물리
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• 제27권4호
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• pp.224-231
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• 2016

The usefulness of Gel Bolus phantom was investigated by comparing the temperature distribution characteristic of the agar phantom produced to investigate the dose distribution characteristic of radiofrequency hyperthermia device with that of the Gel Bolus phantom under conditions similar to those of an agar phantom that can continuously carry out temperature measurement. The temperatures of the agar phantom and the Gel Bolus phantom were raised to $36.5{\pm}3^{\circ}C$ and a temperature sensing was inserted at depths of 5, 10, and 15 cm from the phantom central axis. The temperature increase rate and the coefficient of determination were analyzed while applying output powers of 100 W and 150 W, respectively, at intervals of 1 min for 60 min under conditions where the indoor temperature was in the range $24.5{\sim}27.5^{\circ}C$, humidity was 35~40%, internal cooling temperature of the electrode was $20^{\circ}C$, size of the upper electrode was 250 mm, and the size of the lower electrode was 250 mm. The coefficients of determination of 150 W output power at the depth point of 5 cm from the central axis of the phantom were analyzed to be 0.9946 and 0.9926 in the agar and Gel Bolus phantoms, respectively; moreover, the temperature change equation of the agar and Gel Bolus phantoms with time can be expressed as follows in the state the phantom temperature is raised to $36^{\circ}C:Y(G)$ is equation of Gel Bolus phantoms (in 5 cm depth) applying output power of 150 W. Y(G)=0.157X+36. It can be seen that if the temperature is measured in this case, the Gel Bolus phantom value can be converted to the measured value of the agar phantom. As a result of comparing the temperature distribution characteristics of the agar phantom of a human-body-equivalent material with those of the Gel Bolus phantom that can be continuously used, the usefulness of Gel Bolus phantom was exhibited.

• 한국정보통신학회논문지
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• 제20권10호
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• pp.1927-1934
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• 2016

본 논문에서는 일반적인 실리콘 기반 n-MOSFET(n-type Metal Oxide Semiconductor Field Effect Transistor)의 절연 산화막 계면에서 방사선으로부터 유발되는 누설전류 경로를 차단하기 위하여 I형 게이트 n-MOSEFT 구조를 제안하였다. I형 게이트 n-MOSFET 구조는 상용 0.18um CMOS(Complementary Metal Oxide Semiconductor) 공정에서 레이아웃 변형 기법을 이용하여 설계되었으며, ELT(Enclosed Layout Transistor)와 DGA(Dummy Gate-Assisted) n-MOSFET와 같은 레이아웃 변형 기법을 사용한 기존 내방사선 전자소자의 구조적 단점을 개선하였다. 따라서, 기존 구조와 비교하여 반도체 칩 제작에서 회로 설계의 확장성을 확보할 수 있다. 또한, 내방사선 특성 검증을 위하여 TCAD 3D(Technology Computer Aided Design 3-dimension) tool을 사용하여 모델링과 모의실험을 수행하였고, 그 결과 I형 게이트 n-MOSFET 구조의 내방사선 특성을 확인하였다.

• 농업과학연구
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• 제41권2호
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• pp.149-155
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• 2014

The surface solar radiation is an important indicators for climate and agricultural research over the Earth system. For the climate and agricultural research, long-term meteorological data and accurate measured data are needed. The daily solar radiation from Jan. 2001 to Dec. 2010 have been employed in this study analyze atmospheric transmissivity for Chupungryeong. The corresponding daily value of atmospheric transmissivity is calculated for Chupungryeong meteorological data. In this paper, relationship analysis of daily solar radiation and atmospheric transmissivity is presented. It shows that atmospheric transmissivity over late December peaked in the 2000s, substantially decreased from the early-January, and changed little after that in summer. Reduction of solar radiation caused a reduction of more than 0.3 in atmospheric transmissivity during July to August. It was concluded that the atmospheric transmissivity could be very useful for evaluating solar radiation. Atmospheric transmissivity approach is suitable for daily-term simulation studies and useful for computing solar radiation.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.200.1-200.1
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• 2010

Solar energy is one of the most promising energy resources in the future. For the application and dissemination of solar energy technologies in various fields, reliable data sets of solar irradiation are needed for engineers, researchers, businessmen, and policy makers. Global horizontal solar radiation is needed for the use of flat plate collector, solar domestic hot water system, photovoltaic devices and passive systems like green house. In many countries, solar radiation data accumulated for more then 40 or 50 years and typical weather data are published with average of more then 30 years. In Korea, those global total radiations are measured for about 30 years. With the connections of computer network, measured data could be transmitted to the central control system at key station through Ethernet lines. The data acquisition systems are connected to be automatically controlled by the monitoring network. Global horizontal solar radiation data 16 locations were measured and averaged from 1982 to 2008.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1998년도 추계종합학술대회 논문집
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• pp.597-600
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• 1998

When a semiconductor(pMOSFET) sensor is exposed to ionizing radiation, electrons/holes are generated in its oxide layer. By the phenomenon of hole traps in oxide layer during their move, the characteristics of semiconductor is changed. This paper describes the output characteristic changes of two kind of pMOSFET(domestic, japan) after C0-60 ${\gamma}$-irradiation on them for their application as radiation accumulated dose monitoring sensors. We found the threshold voltage shifts (VT) of pMOSFETs in proportion to irradiated radiation dose and their linear properties. These results make us confirm that we will be able to develop good accumulated radiation dose monitoring sensors.

• Journal of Radiation Protection and Research
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• 제42권3호
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• pp.146-153
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• 2017

Background: Acute radiation syndrome (ARS) primarily refers to damage to the hematopoietic system, myeloid system, and gastrointestinal (GI) system caused by radiation exposure. Such damage progresses to become life-threatening. In particular, as the syndrome develops very rapidly-within several hours from radiation exposure-prompt and accurate diagnosis and treatment are needed, as is further research into appropriate diagnostic and treatment modalities. Materials and Methods: Minipigs, which display human-like properties, underwent whole-body irradiation at 2 or 4 Gy (doses causing hematopoietic ARS) or at higher doses of 7 or 12 Gy. Changes in the blood cells and clinical symptoms were analyzed and we performed a necropsy when the animals succumbed to ARS. Results and Discussion: The minipig irradiated with 2 Gy showed a decrease in white blood cells, including neutrophils, lymphocytes, and platelets in the early stages. However, the blood cell counts gradually increased and returned to normal values. The minipig irradiated with 4 Gy succumbed due to hematopoietic ARS. In contrast, the minipigs irradiated with 7 or 12 Gy exhibited clinical symptoms of combined GI damage and hematopoietic syndrome. Moreover, a characteristic pattern of platelet changes was observed in the 7 and 12 Gy irradiated minipigs. Conclusion: The changes in the platelet count caused by radiation exposure observed in minipigs, which are hematologically and pathohistologically similar to humans, suggest that they can be used as a novel diagnostic criterion.

• 디지털콘텐츠학회 논문지
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• 제13권3호
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• pp.421-429
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• 2012

최근 방사선 의료에서 중재적 시술의 확대로 인하여 시술 건수가 증가하고 있으며, 시술자에 따라 방사선 노출이 다르게 나타 날 수 있으며 시술자와 환자가 받는 방사선 피폭의 증가를 가져온다. 본 연구는 2011년 11월 01일부터 2012년 01월 31일 까지 경북지역 S대학 병원에 내원한 303명의 심장내과 환자를 대상으로 중재적 방사선시술을 시행한 시술자 5명에 따른 방사선 노출특성을 비교분석하였다. 투시시간의 경우 5명의 시술의의 평균 투시시간은 697.95초, cumulative DAP(exp)의 경우 평균 환자 면적선량은 $52,730mGycm^2$, total DAP의 경우 평균 환자면적선량은 $104,875.14mGycm^2$, acquired image의 경우 평균 영상은 855.52frame, exposure image의 평균 영상은 802.2frame로 나타나 통계적으로 유의한 차이를 보였다(p<0.05). 장비의 X선 노출 특성 즉, 투시시간, cumulative DAP(fluro), cumulative DAP(exp), total DAP, acquired image, exposure image는 서로 높은 상관관계를 보이나 cumulative DAP(exp)와 acquired runs는 상관관계를 보이지 않았다. 시술자와 가장 큰 비중을 차지하는 것은 투시시간으로 나타나 투시시간이 길어질수록 방사선 피폭이 증가함을 의미한다. 시술시 피폭선량은 시술자에 따라 시술능력과 경험, 시술의 난이도 및 정밀 시술여부와 관련 있으며, 혈관 조영의 횟수와 투시시간이 정해진 것이 아니어서 인위적인 조절이 어려운 부분이라 할 수 있다. 따라서, 중재방사선 절차를 수행하는 의료진의 실질 피폭을 합리적으로 평가하는 시스템이 필요하며, 불필요한 피폭을 줄이기 위해 시술자를 비롯한 방사선 작업종사자에 대한 자체교육과 훈련이 필요할 것으로 사료된다.

• 한국태양에너지학회 논문집
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• 제32권4호
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• pp.71-81
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• 2012

This study for the understanding of the radiation environment according to the altitude in urban area in the summer observes the long and short wave radiation environment at the 4 urban areas with different height and the 1 suburban area. The results of this study are as follows. (1) When the altitude was high, the more short wave radiation was observed. (2) As the altitude was high, the temperature of atmosphere got lower. And because of that the downward long wave radiation was also lower. This general trend was confirmed through the study. (3) Through the observation of long wave radiation, the upper atmosphere of suburban area had the atmosphere characteristic which the temperature was rising and decreasing faster. Therefore, the difference radiation characteristics between the urban and suburban area were confirmed. (4) The result of the ratio of short wave radiation to long wave radiation(short wave radiation/long wave radiation) according to the altitude and location, the value was increased when the distance was far from the artificiality structure or a heat source, and the urban effect became smaller. Thus, it is expected that the ratio will be an evaluation index for evaluating urbanization effect.

• 분석과학
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• 제5권1호
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• pp.57-61
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• 1992

중성자 스펙트럼을 측정하기 위해 $^6Li$ 중성자 분광계를 설치하고 $^{137}Cs$과 $^{207}Bi$ 점선원을 사용하여 $^6Li$ 검출관의 특성을 파악하고 $^{241}Am-Be$ 중성자 선원을 사용하여 중성자 포획피이크를 측정하였으며, $^6Li$ (n, ${\alpha}$) T 반응에 의한 에너지 파고스펙트럼을 측정하였다. 또한 중성자 선원의 조사 시간의 변화, 선원과 검출관 사이의 거리의 변화, 파고분석기의 문턱조절자를 미세하게 변환시키는 경우에 파고스펙트럼을 측정하였다.