• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.10
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• pp.1117-1127
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• 2012

In this paper, the monopole antenna for satisfying GSM900/DCS1800/PCS1900/UMTS2100 services is designed. We can get the characteristic of the low frequency bands by connecting the front patch to the back patch of the antenna and get the low frequency resonance band using a front patch slit. The proposed antenna total volume is $40{\times}98{\times}1.6\;mm^3$, and it is designed on the FR-4 substrate having a relative dielectric constant of 4.4. As measurement result after fabrication, showed that the resonant frequency bandwidths are 156 MHz(828~984 MHz), 708 MHz(1.476~2.184 GHz) based on the return loss of 10 dB, and the radiation patterns show as the omnidirectional shapes for the E-field and H-field. For analyzing the human effects, the proposed antenna is mounted on the mobile-phone case. The averaged peak SAR over 1 g and 10 g is simulated and measured when the input power is 0.25 W. We have checked the variation of the SAR values when the antenna is mounted 4 different directions, then checked the direction having a relatively higher SAR. The results also satisfied the limiting SAR values which are 1.6 W/kg and 2.0 W/kg averaged over 1 g and 10 g tissues respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.921-932
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• 2010

This paper presents a dual-band array antenna based on a modified Sierpinski fractal structure. Array structure is mirror symmetric, and forms broadside radiation pattern for dual frequency band if the ports are fed with $180^{\circ}C$ phase difference between upper and lower $2{\times}1$ array. To use in-phase corporate feeding circuit, the phase inversion structure is designed by changing the position of patch and ground for upper and lower array. The dimensions of the array antenna is $28{\times}30{\times}5\;cm^3$ and the bandwidth of 855~1,380 MHz(47 %), 1,770~2,330 MHz(27 %) were achieved for -10 dB return loss. The measured gain is 9.06~12.44 dBi for the first band and 11.76~14.84 dBi for the second band. The half power beam width is $57^{\circ}$ for x-z plane and $46^{\circ}$ for y-z plane at 1,100 MHz and $43^{\circ}$ and $28^{\circ}$ at 2,050 MHz, respectively.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.108-115
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• 2013

This study was conducted to suggest a model to calculate the overall heat transfer coefficient of single layer covering for various greenhouse conditions. There was a strong correlation between cover surface temperature and inside air temperature of greenhouse. The equations to calculate the convective and radiative heat transfer coefficients proposed by Kittas were best fitted for calculation of the overall heat transfer coefficient. Because the coefficient of linear regression between the calculated and measured cover surface temperature was founded to 0.98, the slope of the straight line is 1.009 and the intercept is 0.001, the calculation model of overall heat transfer coefficient proposed by this study is acceptable. The convective heat transfer between the inner cover surface and the inside air was greater than the radiative heat transfer, and the difference increased as the wind speed rose. The convective heat transfer between the outer cover surface and the outside air was less than the radiative heat transfer for the low wind speed, but greater than for the high wind speed. The outer cover convective heat flux increased proportion to the inner cover convective heat flux linearly. The overall heat transfer coefficient increased but the cover surface temperature decreased as the wind speed increased, and the regression function was founded to be logarithmic and power function, respectively.

• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.193-206
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• 2004

예로부터 빛고을로 인식되었던 광주가 근세에 이르러 의병활동, 광주학생운동, 5\ulcorner18민주화운동, 아직도 끝나지 않은 이념전쟁으로만 비추어질 수도 있는 지역의 이미지를 재정립하고, 도시 경쟁력의 증대를 위한 방안으로 CI사업 추진계획을 수립하고 3개년에 걸쳐(1999～2001) CI전략 개발, CI디자인 개발, 문화상품 개발, 도시환경디자인 개발 등을 추진하였다. 최근 커뮤니케이션에 있어서 캐릭터는 정보의 시각화라는 측면에서 다른 그래픽 심볼에 비해 설득적이라 할 수 있고, 기존의 심볼의 이미지 보완적 보조심볼로서의 개념이 아닌 독자적인 영역이 구축되어야 하므로 광주광역시 캐릭터 개발은 Character Identity 차원에서 메인캐릭터와 이를 각각의 용도에 맞춰 응용전개시키는 이벤트 캐릭터, 브랜드캐릭터로 구분하여 유형에 따라 다르게 적용되어야 할 적용성 및 활용성에 중점을 두고 개발되었다. 광주광역시의 메인캐릭터 개발컨셉은 "빛"과 "생명"으로 결정된 TCI이념을 활용하는 것과 광주의 상징 요소로서 "무등산"을 활용하는 두 가지 방향에서 개발이 진행되었으며, 1999년 10월의 TCI 추진회의 1차선정을 시작으로 광주시민을 포함한 전국민 설문조사와 2000년 4월의 의회설명회에 이르기까지 다양한 방법을 통해 캐릭터 개발안에 대한 평가와 검토/수정과정을 거쳐 기본캐릭터를 완성하게 되었다. 이를 통해 본 광주광역시의 캐릭터는 중장기적으로 치밀하게 계획되고 실천되어야 하며 변화하는 환경에 효율적으로 대응하는 구체적이고 실천적인 연구평가와 접근방법에 대한 연구 등으로 그 지역의 특징적인 문화를 상품화시키려는 노력이 캐릭터개발을 토대로 뒤따라야 한다. 촉진, 중요 연구 주제의 도출 및 연구 진행 계획을 수립하고, 국제적 산학 협력 강화를 통해 공동 연구를 도출하는 자리를 마련함. $\textbullet$본 학술회의에서 발표된 논문들을 취합하여, 논문집 및 CD-ROM을 제작하여 세계적 수준의 연구 결과를 알리고 이 분야에 관련된 학문, 기술 발전에 큰 도움이 됨.emove effectively radioactivity with in Adsorbent. As cleaning heavy water adsorbent and drying on each condition (temperature for drying and hours for cleaning). Because there is something to return heavy water adsorbent by removing impurities within adsorbent when it is dried o high temperature. After operating, we have been applying this research to the way to dispose heavy water adsorbent. Through this we could reduce solid waste products and the expense of permanent disposal of radioactive waste products and also we could contribute nuclear power plant run safely. According to the result we could keep the best condition of radiation s

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.261-268
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• 2013

This study presents a descriptive research on the degree of self-care related to the prevention of radiation exposure after radioactive iodine therapy and on the relations between self-efficacy and social support to propose nursing interventions required for patients after radioactive iodine therapy. The research period lasted from March to May, 2013. The subjects included 108 patients that were receiving radioactive iodine therapy after thyroidectomy at a cancer hospital in Gyeonggi Province. The subjects scored mean 52.10 on self-care out of full 56 and as for the general characteristics of the subjects, there were significant differences in their self-care according to whether they had a child or not(t=-2.312, p=.023) and interest in health(t=5.689, p<.001). There were significant positive correlations between their self-care and their self-efficacy(r=.610, p<.001), family support(r=.646, p<.001), and medical staff support(r=.276, p=.004). Interest in health(t=5.301, p<.001) was predictor on level 1 of hierarchical regression and interest in health(t=2.140, p=.035) and family support(t=3.353, p=.001) turned out to influence the self-care of the subjects, recording total 46.3% explanatory power. The most important predictor was interest in health(${\beta}$=1.309, p=.035) of self-care.

• Journal of radiological science and technology
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• v.18 no.2
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• pp.87-102
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• 1995

The education of radiologic technology began in the regular institute of higher education in Korea in 1963. Up to now from then, our education to bring up the radiologic technologists has developed greatly in quality and quantity, and now departments of radio-technology are founded in the 16 junior colleges in March, 1995. This study was done to verify the necessity and propriety to reform the education system of radiologic technology which was run as two or three year system of college curriculum for 32 years since 1963, and to search for the method to reform in the future. We got the following results from this research. 1. In the survey, on the desirable education year for radiologic technologists, 63.9 % of professors of department of radio-technology and 63.0 % of radiologic technologists chose the 4 year system, 27.9 % of professors and 34.6 % of radiologic technologists chose the 4 year system added to graduate school. 2. In the survey, on the future development of radiologic equipments and technique, 67.2 % of professors of department of radiologic technology and 86.4 % of radiologic technologists have a view of "revolutional development". Also, on the future tasks or roles of radiologic technologists 95.1% of professors and 94.9% of radiologic technologists have a view that "They will increase". 3. On the necessity of extension of education year to 4 years from 3 years, the factor is that development of medical technique and machinery and tools, advance of qualification of radiologic technologists, enlargement and specialization of the business of the radiologic technologists, ballance of education year with other medical sciences, international competitive power and cooperation of radiologic technology, and education continuation of the graduates of department of radiologic technology. 4. They suggested that in the 4 year curriculum of department of radiologic technology, clinical medicine, quality control of radiation and radiologic equipment, related subjects to the radiologic application and computer application should be enforced and clinical practice should be extended more. 5. On the device to found the 4 year college curriculum of radiologic technology, they suggested that first, 4 year curriculum should be founded through the variety of educational year, secondly, department of radiologic technology should be founded in the 4 year health sciences college, thirdly, educational continuation of the radiologic technologists should be systematized on the basis of life-long education.

• Journal of radiological science and technology
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• v.33 no.1
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• pp.51-59
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• 2010

We developed an analysis software that automatically detects incoming isotopes for multi-purpose gamma-ray detectors. The software is divided into three major parts; Network Interface Module (NIM), Spectrum Analysis Module (SAM), and Graphic User Interface Module (GUIM). The main part is SAM that extracts peak information of energy spectrum from the collected data through network and identifies the isotopes by comparing the peaks with pre-calibrated libraries. The proposed peak detection algorithm was utilized to construct libraries of standard isotopes with two peaks and to identify the unknown isotope with the constructed libraries. We tested the software by using GammaPro1410 detector developed by NuCare Medical Systems. The results showed that NIM performed 200K counts per seconds and the most isotopes tested were correctly recognized within 1% error range when only a single unknown isotope was used for detection test. The software is expected to be used for radiation monitoring in various applications such as hospitals, power plants, and research facilities etc.

• Analytical Science and Technology
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• v.29 no.6
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• pp.293-299
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• 2016

$^{137}Cs$ was investigated in river bottom sediments located in South-Han River basin and it was compared with international case studies to estimate the concentration level of $^{137}Cs$ in river sediment of Korea. The obtained values of $^{137}Cs$ which was analyzed by gamma-ray spectrometry were in the range of <$MDA{\sim}3.80{\pm}0.14Bq/kg{\cdot}dry$ and similar to the $^{137}Cs$ activities in soil of Korea. According to international case studies, $^{137}Cs$ activities were between 3.7 to $15,396Bq/kg{\cdot}dry$, when pollutants such as nuclear power plant accidents and radiation leaks were present near the rivers. The $^{137}Cs$ activities showed a variety of distribution depending on the country, when pollution occurs and survey time. Also, $^{137}Cs$ activities of river sediments without pollution sources were mostly less than $10Bq/kg{\cdot}dry$ in other countries. It was comparable with the obtained $^{137}Cs$ activities in this study. The obtained values provide useful information on the background concentration of $^{137}Cs$ in river sediment and will be able to use a basis for determining contamination of $^{137}Cs$ in the river.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1273-1279
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• 2016

Production of iodine-131 by neutron activation of tellurium in tellurium dioxide ($TeO_2$) material requires a target that meets the safety requirements. In a radiopharmaceutical production unit, a new lid for a can was designed, which permits tight sealing of the target by using tungsten inert gaswelding. The leakage rate of all prepared targets was assessed using a helium mass spectrometer. The accepted leakage rate is ${\leq}10^{-4}mbr.L/s$, according to the approved safety report related to iodine-131 production in the TRIGA Mark II research reactor (TRIGA: Training, Research, Isotopes, General Atomics). To confirm the resistance of the new design to the irradiation conditions in the TRIGA Mark II research reactor's central thimble, a study of heat effect on the sealed targets for 7 hours in an oven was conducted and the leakage rates were evaluated. The results show that the tightness of the targets is ensured up to $600^{\circ}C$ with the appearance of deformations on lids beyond $450^{\circ}C$. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modes-convection, conduction, and radiation. The quantities of heat generated by gamma and neutron heating were calculated by a validated computational model for the neutronic simulation of the TRIGA Mark II research reactor using the Monte Carlo N-Particle transport code. Using the heat transfer equations according to the three modes of heat transfer, the thermal study of I-131 production by irradiation of the target in the central thimble showed that the temperatures of materials do not exceed the corresponding melting points. To validate this new design, several targets have been irradiated in the central thimble according to a preplanned irradiation program, going from4 hours of irradiation at a power level of 0.5MWup to 35 hours (7 h/d for 5 days a week) at 1.5MW. The results showthat the irradiated targets are tight because no iodine-131 was released in the atmosphere of the reactor building and in the reactor cooling water of the primary circuit.

• Korean Journal of Optics and Photonics
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• v.16 no.3
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• pp.287-294
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• 2005

In this paper, an optical true time-delay (TTD) for two-dimensional (2-D) phased array antennas (PAAs), composed of a multi-wavelength optical source and a fiber optic delay line matrix consisting of $2\times2$ optical switches with optical fiber connected between cross ports, has been proposed. A 2-bit $\times4-bit$ optical TTD for 10-GHz 2-D PAAs has been implemented by cascading a wavelength dependent TTD (WD-TTD) and a wavelength independent TTD (WI-TTD). The unit time delay for WD-TTD and WI-TTD have been chosen as ${\Delta}T=12ps$ and $\Delta\tau=6ps$, respectively. Time delay have been measured at all radiation angles. The maximum delay error for WD-TTD was measured to be 3 ps due to jitter incurred from gain switching. For the case of WI-TTD, error was within ${\pm}\;1\;ps$. The proposed optical TTD for a 2-D PAA has the following advantages: 1) higher gain compared to one-dimensional linear PAAs, 2) stabilization of optical power and wavelength by using a multi-wavelength optical source, and 3) fast beam scan and simple operation due to electronic control of the $2\times2$ optical switches matrix on a column-by-column basis.