• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.885-888
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• 1999

Radiation characteristics of axial elementary current source on the cylindrical bianisotropic substrateloaded with bianisotropic superstrate layer are presented. The effects of bianisotropic superstrate cover on the radiation problems of a microstrip antenna are studied. This investigation is performed by using the Green function formulation in the spectral domain. Numerical results for the radiation pattern of the bianisotropic superstrate-loaded microstrip antenna is analyzed.

• 한국축산식품학회지
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• 제29권5호
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• pp.573-578
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• 2009

This study examined the effect of gamma irradiation on shelf-life extension and sensory characteristics of dak-galbi. Commercial dak-galbi sauce was gamma-irradiated at 0, 5, 10, 15, 20, 25, and 30 kGy. The dak-galbi sauce (200 g) was then added to diced chicken (800 g) for cooking, and the cooked dak-galbi samples in vacuum bags were stored at $35^{\circ}C$ for 5 d. Dak-galbi samples were analyzed on d 0, 1, 2, 3, 4, and 5 for microbial analysis (plate count agar), thiobarbituric acid (TBARS) and volatile basic nitrogen (VBN) measurements, and on d 0 for sensory evaluation. On d 0, total bacterial populations were below detection limit after dak-galbi marinated with the gamma-irradiated (${\geq}15\;kGy$) sauces were cooked, and the samples marinated with higher dose irradiated dak-galbi sauce had lower (p<0.05) bacterial populations during storage. TBARS values of the dak-galbi samples marinated with non-irradiated sauce were not different ($p{\geq}0.05$) with those marinated with irradiated sauces on d 0, and the TBARS values increased (p<0.05) during storage at $35^{\circ}C$, regardless of irradiation dose. In the VBN analysis, there was no difference ($p{\geq}0.05$) in VBN values among irradiation doses on d 0, but VBN values decreased (p<0.05) as irradiation dose increased during storage. Moreover, there were no significant differences ($p{\geq}0.05$) in sensory characteristics among irradiation doses. These results indicate that use of gamma irradiation on dak-galbi sauce may be useful in shelf-life extension without compromising the sensory characteristics of dak-galbi.

• The Journal of the Acoustical Society of Korea
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• 제20권2E호
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• pp.46-50
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• 2001

The characteristics of radiation impedance are analyzed by algorithms which consists of Finite Element Method (FEM) and Hybrid type Infinite Element Method. The changes of radiation impedance for piston source according to the size and the material properties of baffles are studied. The results of the radiation impedance for rigid finite baffle coincide with other reports. The more the material properties of baffle that comes across the acoustic medium, the more the calculation results of radiation impedance approach the ones without baffle. Therefore, these results can be applied to the design and the radiation characteristics analysis of acoustic transducers.

• 소음진동
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• 제7권3호
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• pp.457-466
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• 1997

The experimental and analytical study was conducted to determine the noise transmission characteristics of acoustically loaded steel plate of rectangular enclosure and to investigate the sound radiation characteristics through out the enclosure. The vibrations of acoustically loaded plate give rise to sound radiations and generate the reverberant space that the sound field exists very close to a vibrating plate. Acoustic transmission loss is measured from the incident intensity into the plate and the transmitted intensity through out the plate. Sound radiation patterns are measured from both acoustic intensity technique and surface intensity technique. Those resultant patterns and vibrational modes are vital in understanding the relations between vibration and noise in the near field out of vibrating plate.

• 소음진동
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• 제8권4호
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• pp.603-608
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• 1998

In order to obtain basic data for the prediction of railway noise propagation, the noise radiation characteristics (source position, radiation directivity, etc) of trains were measured by using the sound intensity method. The measurements were performed at a side of railway by setting an intensity-probe array. As the measurement results, it was found that rolling noise due to interaction between wheel and rail and motor noise radiation from the lower part of train are dominant. The location of main sound sources can be described as being at the height of 0.1m in the center line of track, and the radiation directivity in the cross section of actually running trains are presented as a dipole source.

• 대한전자공학회논문지TC
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• 제44권11호
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• pp.33-41
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• 2007

기판의 크기가 마이크로스트립 패치 안테나의 방사특성에 미치는 영향에 대하여 알아보았다. 기판의 폭을 고정시키고 길이를 변화시킬 때 방사패턴 특성이 크게 변화하나 기판 길이를 고정시키고 폭을 변화시킬 때는 방사패턴 특성이 거의 변화하지 않음을 볼 수 있었다. 기판 크기에 따른 방사패턴 특성의 변화는 기판 두께가 두꺼울 때가 작을 때보다 더 큼을 볼 수 있었다.

• Safety and Health at Work
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• 제12권4호
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• pp.445-451
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• 2021

Background: This study aimed to evaluate the reliability and validity of the self-administered questionnaire for Korean radiation workers. Methods: From May 24, 2016, to June 30, 2017, 20,608 participants completed the questionnaire, providing information on sociodemographics, lifestyle, work history and practices, medical radiation exposure, and medical history, which was linked to the National Dose Registry and the National Cancer Registry. The validity of the questionnaire was evaluated using the responses of 20,608 workers, and reliability was evaluated using the responses of 3043 workers who responded to the survey twice. Results: Responses concerning demographic characteristics and lifestyle showed reliability with a moderate-to-high agreement (kappa: 0.43-0.99), whereas responses concerning occupation and medical radiation exposure had a wide range of agreement (kappa: 0.05-0.95), possibly owing to temporal variability during employment. Regarding validity, responses to the question about the first year of employment had an excellent agreement with the national registry (intraclass correlation coefficient = 0.9); however, responses on cancer history had a wide range of agreement (kappa: 0.22-0.85). Conclusion: Although the reliability and validity of the questionnaire were not distinguished by demographic characteristics, they tended to be low among participants whose occupational radiation exposure was minimal. Overall, the information collected can be reliable for epidemiological studies; however, caution must be exercised when using information such as medical exposure and work practices, which are prone to temporal variability.

• 한국음향학회지
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• 제22권1호
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• pp.54-60
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• 2003

구형 배플상의 피스톤 음원에 대하여 방사임피던스 특성을 2차원 축대칭 유한요소법과 하이브리드형 무한요소법을 사용하여 수치 해석하였다. 강체 배플에 있어서 피스톤 음원의 방사면 크기에 따른 자기방사임피던스 변화와 피스톤 음원간의 상호방사임피던스 변화를 계산한 결과는 알려진 해석해와 잘 일치하였다. 또한 비강체 배플의 적용에 따른 자기방사임피던스 및 상호방사임피던스의 변화를 규명함으로서 음향변환기의 설계 및 방사특성 해석에 응용되어질 것으로 기대된다.

• 한국태양에너지학회 논문집
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• 제35권2호
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• pp.21-31
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• 2015

The purpose of this study is to understand the characteristics of urban climate in several cities, from observing radiation according to wavelength band(UV, short and long wave radiation). Observation start from 5 May to 31 August 2013. The followings are the main results from this study. 1) In every observation area, greater amounts of short-wave radiation have been recorded in May compared to June. Even though the highest solar elevation occurs in June, May sees clearer days, which has attributed to the outcome. 2) The analysis concerning the correlation between ultraviolet radiation and shortwave radiation have revealed that regions closer to the Daegu area have stronger correspondence. 3) The time series of daily long-wave radiation shares a similar tendency with the time series of air temperature, and the maximum value was recorded at 14:00 and 15:00.

• 한국치위생학회지
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• 제15권1호
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• pp.101-109
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• 2015

Objectives: The purpose of the study is to investigate the knowledge and attitude towards radiation protection after radiation safety management education in dental hygiene students. Methods: After receiving informed consents, a self-reported questionnaire was carried out for 135 dental hygiene students in Busan on June 17 for preliminary survey and September 3 for post-education survey, 2011. The questionnaire was modified from Han and consisted of 5 questions of general characteristics, 6 questions of radiation use, 7 questions of scholastic characteristics, 15 questions of knowledge towards radiation safety management, and 15 questions of attitude towards radiation safety management. Cronbach's alpha was 0.808 in the knowledge towards radiation safety management. Attitude towards radiation safety management included 15 questions of general attitude towards radiation safety management, individual and patient, and attitude toward radiation exposure reduction measured by Likert 5 scale. Cronbach's alpha was 0.970 in the attitude towards radiation safety management. Data were analyzed using SAS version 9.2 for educational analysis, technical analysis and multivariate analysis, paired t-test, and GLM. Results: Significant differences were shown in the knowledge and attitudes towards radiation safety management; the level of knowledge was respectively $9.8{\pm}3.0$ and $12.9{\pm}1.9$ points before and after education, and the level of attitude was $4.28{\pm}0.51$ and $4.53{\pm}0.47$ before and after the education. The levels of knowledge and attitude according to general characteristics showed a significant differences in grade and academic results. Post-education survey suggested that the education is very important and necessary and can change the knowledge and attitude towards radiation safety management in the dental hygiene students. Conclusions: Through the radiation safety management education, the levels of knowledge and attitude towards radiation safety management have changed significantly, which showed that the radiation safety management education proved to be very effective. Therefore, an effective radiation safety management education program is necessary to improve the levels of knowledge and attitude towards radiation safety management in the dental hygiene students.