• 천문학회보
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• 제36권2호
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• pp.140.2-140.2
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• 2011

We present high-resolution radial velocity (RV) measurements of K2 giant HD 66141 from December 2003 to January 2011 using the fiber-fed Bohyunsan Observatory Echelle Spectrograph (BOES) at Bohyunsan Optical Astronomy Observatory (BOAO). We find that the RV measurements for HD 66141 exhibit a periodic variation of 480 days with a semi-amplitude of 146 m/s. We do not find the correlation between RV variations and a chromospheric activity indicator (H line). The Hipparcos photometry as well as bisector velocity span (BVS) also do not show any obvious correlations with RV variations. Thus, Keplerian motion is the most likely explanation, which suggests that the RV variations arise from an orbital motion. Assuming a possible stellar mass of 1.5 $M{\odot}$, for HD 66141, we obtain a minimum mass for the planetary companion of 7.4 MJup with an orbital semi-major axis of 1.4 AU, and an eccentricity of 0.07. We support that planet occurrence rate around evolved stars is more than 10 % (Dollinger et al. 2009) as well as more massive stars do form significantly more massive planetary companions (Johnson et al. 2007; Lovis & Mayor 2007; Dollinger et al. 2009).

• 천문학회지
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• 제46권5호
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• pp.191-200
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• 2013

Full-disk solar images are provided by many solar telescopes around the world. However, the observed images show Non-Radial Variation (NRV) over the disk. In this paper, we propose algorithms for detecting distortions and restoring these images. For detecting NRV, the cross-correlation coefficients matrix of radial profiles is calculated and the minimum value in the matrix is defined as the Index of Non-radial Variation (INV). This index has been utilized to evaluate the H images of GONG, and systemic variations of different instruments are obtained. For obtaining the NRV's image, a Multi-level Morphological Filter (MMF) is designed to eliminate structures produced by solar activities over the solar surface. Comparing with the median filter, the proposed filter is a better choice. The experimental results show that the effect of our automatic detection and restoration methods is significant for getting a flat and high contrast full-disk image. For investigating the effect of our method on solar features, structural similarity (SSIM) index is utilized. The high SSIM indices (close to 1) of solar features show that the details of the structures remain after NRV restoring.

• Journal of Astronomy and Space Sciences
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• 제34권4호
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• pp.303-314
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• 2017

With increased human activity in space, the risk of re-entry and collision between space objects is constantly increasing. Hence, the need for space situational awareness (SSA) programs has been acknowledged by many experienced space agencies. Optical and radar sensors, which enable the surveillance and tracking of space objects, are the most important technical components of SSA systems. In particular, combinations of radar systems and optical sensor networks play an outstanding role in SSA programs. At present, Korea operates the optical wide field patrol network (OWL-Net), the only optical system for tracking space objects. However, due to their dependence on weather conditions and observation time, it is not reasonable to use optical systems alone for SSA initiatives, as they have limited operational availability. Therefore, the strategies for developing radar systems should be considered for an efficient SSA system using currently available technology. The purpose of this paper is to analyze the performance of a radar system in detecting and tracking space objects. With the radar system investigated, the minimum sensitivity is defined as detection of a $1-m^2$ radar cross section (RCS) at an altitude of 2,000 km, with operating frequencies in the L, S, C, X or Ku-band. The results of power budget analysis showed that the maximum detection range of 2,000 km, which includes the low earth orbit (LEO) environment, can be achieved with a transmission power of 900 kW, transmit and receive antenna gains of 40 dB and 43 dB, respectively, a pulse width of 2 ms, and a signal processing gain of 13.3 dB, at a frequency of 1.3 GHz. We defined the key parameters of the radar following a performance analysis of the system. This research can thus provide guidelines for the conceptual design of radar systems for national SSA initiatives.

• 한국방사선학회논문지
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• 제6권1호
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• pp.79-82
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• 2012

요오드는 원자력 시설에서 사고가 발생할 경우 방사선 피폭을 검토할 때 고려해야 할 중요한 핵종 중 하나이다. 그러므로 체르노빌 사고 시 대기 중에는 유기물 형태의 요오드가 비유기물 형태의 요오드보다 많이 관찰되었다. 본 연구에서는 시료의 양 및 측정시간에 변화를 주었으며, 또한 $^{131}I$ 액체선원을 사용하여 증류수에 희석한 시료 및 다시마를 함께 섞은 시료를 이용하여 검출하한치를 측정 분석하였다. 방사능농도 하한치에 들어 인체에는 무해함을 확인 할 수 있었다. $^{131}I$선원의 시간이 흐를수록 카운트가 줄어듦을 알 수 있었다. 반감기를 계산해본 결과 7~9사이의 결과를 얻었고, $^{131}I$를 혼합한 시료의 경우 최고 7일이 지난 후에는 초기 조건에서 반으로 감소한다는 것을 알 수 있었다.

• 한국물환경학회지
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• 제23권2호
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• pp.201-205
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• 2007

This paper reports the amount of $^{222}Rn$ and $^{238}U$ in 18 sites of ground water and 30 sites of surface water. The instrument used to count $^{222}Rn$ activity was the liquid scintillation counter (LSC) which could resolute ${\alpha}$ and ${\beta}$ radiations. And $^{238}U$ was analyzed by the inductively coupled plasma (ICP). Radon and Uranium were not detected in raw and treated water which were sampled in a water treatment plant. However, radon ($^{222}Rn$) was high concentration in ground water from Jeon-la, Gang-won. So was uranium ($^{238}U$) in case of ground water from Gang-won, Choong-chung. Radon ($^{222}Rn$) activities were detected less than 15 pCi/L at 5 sampling points, 15~300 pCi/L at 7 sampling points, 300~4000 pCi/L at 6 sampling points. However, Radon ($^{222}Rn$) activities of all ground water samples were less than 4,000 pCi/L, which was bellow American Alternative Maximum Contamination Level (AMCL). Uranium ($^{238}U$) concentrations were less than $0.1{\mu}g/L$ at 5 sampling points, from $0.1{\mu}g/L$ to $20{\mu}g/L$ at 13 sampling points. Uranium was not detected in about 30% of the whole samples, but the concentration ranged from relatively low to high concentrations depending on the sampling point. The minimum detectable activity (MDA) of radon was 15 pCi/L. and the detection limit of uranium was $0.1{\mu}g/L$.

• 대한원격탐사학회지
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• 제30권4호
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• pp.465-480
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• 2014

본 연구에서는 최근 발생한 집중호우 사례들 중 예보가 어려워 피해가 컸던 두 사례(2010년 9월 21일, 2011년 8월 9일)에 대해 적외영상과 수증기영상의 시 공간적인 변화 특성을 분석하였다. 두 사례에서 한반도지역에 집중호우를 유발한 대류 세포들은 적외영상에서 하층운이 광범위하게 분포하고 수증기 영상에서는 명역과 암역의 경계(boundary)에서 생성되는 특징을 보였다. 또한 대류 세포들의 이동속도 차에 의한 총 5번의 병합과정 중 4번의 병합과정에서 대류 세포들의 병합 후 대류 세포는 더욱 발달되었으며 강수 강도도 급격하게 강화되었다. 대류시스템에서의 강우강도 변화는 휘도온도의 평균보다 최소 휘도온도의 시간적 변화와 밀접하게 관련된 것으로 판단되며 대류 세포들의 병합도 집중호우의 강도 변화에 영향을 주는 주요 인자로 생각된다. 대류 세포들의 병합은 영상동화를 통해 어느 정도 예측이 가능하지만 대류 세포의 탐지는 적외 및 수증기 영상 모두에서 일정 강도 이상 발달한 상태에서만 탐지가 가능하였다.

• 약학회지
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• 제45권6호
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• pp.650-655
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• 2001

Carvedilol is a nonselective $\beta$-blocking agent with vasodilating properties that are attributed mainly to its blocking activity at $\alpha$$^{1}$-receptors. Carvedilol is used in the treatment of mild to moderate hypertention and angina pectoris and is often used in combination with other drugs. This study was carried out to evaluate the bioequivalence and pharmacokinetics of two carvedilol 25mg tablet formulations according to the guidelines of Korea Food and Drug Administration (KFDA). Twenty healthy volunteers are enrolled and received a single dose (25mg as carvedilol) of each drug in the fasting state, in a randomized 2-way crossover design. After oral administration, blond samples were collected for a period of 30 hours. Plasma concentrations of carvedilol were determined by a rapid and sensitive HPLC method with spectrofluorometric detection. The major pharmacokinetic parameters such as AU $C_{0-}$30hr/, AU $C_{inf}$ , $C_{max}$, $T_{max}$, $t_{1}$2 / Cl/F and V $_{\beta}$//F were calculated. ANOVA test and t-test were utilized for the statistical analysis of each parameter. The results showed that the differences in AU $C_{0-}$30hr/, $C_{max}$ and $T_{max}$ between two were ~5.66, 1.74 and 0.00%, respectively. Minimum detectable differences ($\Delta$) at $\alpha$=0.05 were less than$\pm$ 20% except $T_{max}$ (8.44, 18.36, and 33.86%, respectively). The 90% confidence intervals of all parameters were within $\pm$20% (-10.60~ -0.72, -9.00~12.49 and -19.81~19.81%, respectively). Therefore, it is concluded that the two formulations are bioequivalent for both the extent and the rate of absorption after single dose administration.ation.ion.ion.ation.ion.n.

• Journal of Radiation Protection and Research
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• 제45권3호
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• pp.142-146
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• 2020

Background: Tritium (³H) analysis in groundwater was difficult because of its low activity. Therefore, the electrolytic enrichment method was used. To improve the detection limit and for performing simple analysis, a high-volume counting vial with the available liquid scintillation counter (LSC) was investigated. Further, it was compared with a conventional 20-mL counting vial. Materials and Methods: The LSC with the electrolytic enrichment method was used ³H analysis in groundwater. A high-volume 145-mL counting vial was compared with a conventional 20-mL counting vial to determine the counting characteristics of different LSCs. Results and Discussion: When a Quantulus LSC was used, the counting window between channels 35 and 250 was used. The background count was approximately 1.86 cpm, and the counting efficiency increased from 8% to 40% depending on the mixing ratio of the volume of sample and cocktail solution. For LSC-LB7, the optimum counting window was between 1 and 4.9 keV, which was selected by the factory (Hitachi Aloka Medical Ltd., Japan) by considering quenching using a standard external gamma source. The background count of LSC-LB7 was approximately 3.60 ± 0.29 cpm when the 145-mL vial was used and 2.22 ± 0.17 cpm when the 20-mL vial was used. The minimum detectable activity (MDA) of the 20-mL vial was greater for LSC-LB7 than for Quantulus. The MDA with the 145-mL vial was improved to 0.3 Bq/L when compared with the value of 1.6 Bq/L for the 20-mL vial. Conclusion: The counting efficiency when using the 145-mL vial was 27%, whereas it was 18% when using the 20-mL vial. This difference can be attributed to the vial volume. The figure of merit (FOM) of the 145-mL vial was four times greater than that of the 20-mL vial because the volume of the former vial is approximately seven times greater than that of the latter. Further, the MDA for ³H decreased from 1.6 to 0.3 Bq/L. The counting efficiency and FOM of LSC-LB7 was slightly less than those of Quantulus when the 20-mL vial was used. The background counting rate of the Quantulus was lower than that of the LSC-LB7.

• Journal of Radiation Protection and Research
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• 제47권4호
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• pp.204-213
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• 2022

Background: The accident at the Fukushima Daiichi nuclear power plant increased the level of anxiety related to the radioactive contamination of various foods sourced in Japan. Particularly, after the accident, the detection of artificial radionuclides in locally produced foods raised food safety concerns. In this study, the radioactivity concentrations and annual ingestions of ⁴⁰K and ¹³⁷Cs in food products commonly and frequently consumed by the general public were investigated, and the annual effective dose of each was evaluated. Materials and Methods: The 2016-2018 data from the Radiation Safety Management Report released by the Korea Nuclear Safety Technology Center was referenced for the evaluation of the amounts of ⁴⁰K and ¹³⁷Cs contained in food. Using the food-ingestion survey mentioned above as a reference, we selected 62 foods to include in our radioactivity concentration and dose assessment. We also developed a questionnaire and evaluated the responses from the subjects who answered the questionnaire. Results and Discussion: The radioactivity concentration of ¹³⁷Cs was found to be close to or below the level of minimum detectable activity. Additionally, the annual ingestion of 62 foods was 294.77 kg/yr, the effective doses from ⁴⁰K and ¹³⁷Cs were 136.4 and 0.163 μSv/yr, respectively. Conclusion: Thus, the findings confirmed that the effective dose from ⁴⁰K and ¹³⁷Cs in food tends to be lower than the effective dose limit of 1 mSv/yr suggested by the International Commission on Radiological Protection (ICRP) Publication 60. The questionnaire developed in this study is expected to be useful for estimating the annual effective dose status of Korean adults who consume foods containing ⁴⁰K and ¹³⁷Cs.

• 지역사회간호학회지
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• 제11권1호
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• pp.21-36
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• 2000

The purpose of this study was to assess the needs of breast self examination education (BSEE) programs for developing nursing centers. A first, we reviewed the literature of activity and management-related factors of nursing centers: and, second. we used a questionnaire to discover the degree of knowledge, attitude, and practice on breast cancer, as well as an individual's intention to participate BSEE program. 1. Reviewing the literatures of nursing center activities. Nursing centers which were administered by a professional nurse are an ideal site for faculty and student practices. With the use of nursing models of health. professional nurses in nursing centers diagnose and treat human responses to potential and actual health problems and offer holistic, client-centered health service. In nursing centers professional nursing services include health education, health promotion, and health-related research. A nursing center is comprised of the advisory and exacutive commitee; the advisory commitee serves consultants and links community needs to the nursing center, while the director of the exacutive commitee identifies the potential resources to generate funds, support, and facilitate the activities of staffs in a nursing center. Nursing centers mobilize various financal resources for reimbursement of services from college and insurance companies, collect minimum service fees from the client, and further collect fees for providing programs to community groups, this also includes membership fees, and donations. The services provided by nursing centers focus on services related to primary prevention, health maintenance & health promotion, direct nursing care for acute & chronic diseases, and holistic care for actual and potential health problems. The client satisfaction for the services was high. Students also showed positive reponses for their clinical experiences and independent working conditions. 2. The degree of knowledge, attitudes, and practices for breast cancer. and an individual's intention to participate in the BSEE program. The subjects of this study were 308 females in K-city in the Republic of Korea. Data were collected using a self-administered questionnaire. The mean age of the respondents was 35.0 years old. Those who already participated in the BSEE were 64.9%, and those who had support and encouragement to practice BSE from significant others were 25.1 %. Clients intent to participate in the BSEE were 37.0%. The mean score of knowledge(2.4 out of 5 points) and practices(1.8 out of 5 points) for breast cancer were quite low, but the mean score of attitudes was relatively positive04.5 out of 20 point) for breast cancer. Those who already had BSEE showed significantly high scores in knowledge(t=6.48, p<0.01), attitudes (t=10.54, p<0.01). and practices(t=57.07, p<0.001) for breast cancer than those who had not participated in the BSEE. In all age groups no intention to participate in the BSEE was higher than who the intention to participate. These findings suggest some strategies should be developed to increase the awareness of breast cancer's early detection.